CN111233975A

CN111233975A - Polypeptide mn capable of targeting integrin and application thereof in preparation of tumor targeting drugs

Info

Publication number: CN111233975A
Application number: CN201811433490.9A
Authority: CN
Inventors: 陆伟跃; 李锦阳; 谢操
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2018-11-28
Filing date: 2018-11-28
Publication date: 2020-06-05

Abstract

The invention belongs to the field of pharmacy, and relates to a highly stable multifunctional short peptide mn which has high affinity with integrin and can target tumor new vessels, tumor mimicry vessels and tumor cells, a polypeptide modified compound, a drug delivery system and application thereof in preparing tumor diagnosis and treatment drugs. The experiment shows that: the mn-modified drugs are specifically taken up by the positive cells expressing the integrin and tumor tissues, and have good tumor targeting and imaging functions; the drug delivery system constructed by the mn-modified high-molecular carrier material effectively delivers the encapsulated drug to a target tissue, and the diagnosis and treatment effects of tumors are remarkably improved. Compared with the widely used integrin ligand c (RGDyK), the medicine prepared by the invention has better stability in mn serum and stronger binding capacity with the integrin, the immunogenicity of the modified carrier system is obviously lower than that of the carrier system modified by c (RGDyK) and the like, the mediated active targeting medicine delivery effect in vivo is better, and the medicine has good application prospect in tumor diagnosis and targeting treatment.

Description

Polypeptide mn capable of targeting integrin and application thereof in preparation of tumor targeting drugs

Technical Field

The invention belongs to the field of pharmacy, relates to polypeptide mn capable of targeting integrin, in particular to highly stable multifunctional polypeptide mn and derivatives thereof which have high affinity with integrin and target tumor neovascularization, tumor mimicry vessels and tumor cells, a medicament compound of mn polypeptide and a medicament delivery system modified by mn polypeptide, and particularly relates to mn (amino acid sequence mnRwr; capital letters represent L-configuration amino acids, and lowercase letters represent D-configuration amino acids) and derivatives thereof, a compound of diagnostic medicaments and therapeutic medicaments thereof, a modified high molecular carrier material thereof, a medicament delivery system such as liposome, micelle, disc, nanoparticle, biomembrane coated nanoparticle and the like constructed by the modified high molecular carrier material, and application of the modified high molecular carrier material in preparation of medicaments for tumor diagnosis and targeted therapy.

Background

The prior art discloses that tumors are diseases which are at present seriously threaten human life and health, have high mortality rate and are in the front of disease mortality rate, and are in an ascending trend. The traditional chemotherapy is used as a main means for tumor drug treatment, and has the defects of poor selectivity to tumor tissues, high toxicity, narrow treatment window, easy generation of multi-drug resistance and the like. In order to overcome the defects of the traditional intervention means, active targeting in recent years becomes an important strategy for improving the tumor targeted treatment effect. Research reports that an active targeting strategy mainly aims at a highly expressed receptor or transporter in a tumor tissue, and a corresponding ligand which has recognition and binding capacity with a specific receptor or transporter is utilized to deliver a drug or a nano drug delivery system into the tumor tissue or cells, wherein the commonly used corresponding ligand comprises a monoclonal antibody, a polypeptide, a nucleic acid aptamer, a small molecular compound and the like; the ligand modified drug or nano drug delivery system can deliver the drug to tumor tissues and cells through specific recognition, combination and internalization of cell surface receptors or transporters and ligands, thereby realizing the active targeting of the drug to tumors.

The prior art discloses that integrins are an important class of cell surface receptors whose ligands are mainly Extracellular Matrix (EMC) proteins, such as: collagen, fibronectin, laminin and the like, and integrin plays an important role in embryonic development, tumorigenesis, invasion and metastasis, inflammation, wound healing and other processes by recognizing the extracellular matrix proteins to mediate cell-extracellular matrix and cell-cell adhesion reactions, accept and conduct cascade signals and regulate cell survival, movement, proliferation and other biological processes. Since the introduction of integrin in Hynes in 1987, the cell adhesion and movement behaviors involved in integrin in tumorigenesis and metastasis, cell proliferation, and lymphocyteThe involvement of mechanisms such as homing, apoptosis, signaling and tumor angiogenesis is increasingly recognized, and more than 20 integrins are heterodimeric transmembrane glycoproteins, whose subunits alpha and β each have a large extracellular N-terminal domain, which bind to specific ligands via conformational changes of their folding helices, and whose intracellular domains can be linked to the relevant cytoskeletal proteins_vβ₃Is the most widely studied member of integrin family at present, has low expression even no expression in dormant endothelial cells and other normal tissues, but has sharply increased expression quantity in various tumor cells and tumor neovascular endothelial cells, thereby becoming an ideal target for inhibiting tumor and tumor angiogenesis, and the integrin α_vβ₃Rw (amino acid sequence RwrNM; wherein capital letters represent L-configuration amino acids, and lowercase letters represent D-configuration amino acids) is a pentapeptide screened by phage display technology, and the pair α is proved by research_vβ₃Has high affinity activity, mn (amino acid sequence mnRwr; wherein capital letters represent L-configuration amino acids, and lower case letters represent D-configuration amino acids) is an optical isomer of RW, and the pair α is proved by experiments_vβ₃Has high affinity activity, but has not been reported in the research of tumor targeted diagnosis and treatment.

Based on the basis and the current situation of the prior art, the inventor of the application intends to provide the polypeptide mn capable of targeting integrin and the application thereof in tumor targeted diagnosis and treatment, in particular to a pharmaceutical composition modified by mn polypeptide and derivatives thereof and a modified drug delivery system, so as to realize targeted diagnosis and treatment of tumors.

Disclosure of Invention

The invention aims to provide polypeptide mn capable of targeting integrin and application thereof in preparing tumor targeted diagnosis and treatment medicines based on the basis and the current situation of the prior art, in particular to a medicine compound modified by mn polypeptide and derivatives thereof and a modified drug delivery system, so as to realize targeted diagnosis and treatment of tumors.

The invention provides a novel polypeptide targeting integrin with high expression of various tumors, which is used for diagnosis and treatment of tumor targeted drug delivery, can overcome the problem of insufficient stability of the existing ligand polypeptide c (RGDyK), improve the binding activity with target protein integrin, improve the immunogenicity generated by the existing ligand polypeptides c (RGDyK), RW and the like used for modifying a carrier system, and achieve better in-vivo tumor targeting and diagnosis and treatment effects.

In the invention, mn polypeptide (amino acid sequence mnRwr, wherein capital letters represent L-configuration amino acids, and lowercase letters represent D-configuration amino acids) and mn and derivatives thereof are prepared to modify drug molecules and polymer carrier materials, and a drug compound and an active targeting drug delivery system are constructed.

Specifically, the invention designs and prepares mn polypeptide (amino acid sequence mnRwr; capital letter represents L configuration amino acid, and lower case letter represents D configuration amino acid) and its derivative by utilizing solid phase polypeptide synthesis technology, and the stability is stronger than that of c (RGDyK); has high affinity with integrin and dissociation constant K_DLower than c (RGDyK).

After the mn designed by the invention is connected with cysteine, thiol in the molecule and maleimide functionalized imaging substances such as fluorescent substances FITC, FAM, 5-TAMRA, 6-TET, HEX, 6-JOE and the like, near infrared dyes Cy3, Cy3.5, Cy5, Cy5.5, Cy7, IR783, IR820, DiR, DiD, BIDIPY630/650-X, BIDIPY650/665-X, BIDIPY665/676, TO-PRO-3, TO-PRO-5 and the like, chemiluminescent substances, isoluminol, AMPPD, CSPD, CDP-star, lucigenin and the like, magnetic resonance imaging agents Gd-DTPA, radiographic imaging agents^99mTc-DTPA、¹⁸F-FDG、¹⁸F-Al-NOTA、¹⁸F-Al -DOTA、⁶⁸Ga-NOTA、⁶⁸Ga-DOTA、¹¹¹In-DTPA and the like to form a composite.

The mn and derivative modified drug thereof designed by the invention comprises polypeptide-polypeptide drug complexes such as pH sensitive hydrazone bond formed by reaction of maleimide and hexylhydrazine derivative (related to ketone or aldehyde group-containing drugs such as adriamycin and epirubicin), or disulfide bond formed by reaction of 3- (2-pyridinedithiol) propionic acid derivative (related to drugs containing hydroxyl or amino groups such as paclitaxel, docetaxel, captaxel, camptothecin, hydroxycamptothecin, irinotecan, 9-nitrocamptothecin, vinblastine and vincristine), or pH sensitive borate formed by reaction of dopamine and boric acid group in drugs (related to drugs containing boric acid group such as bortezomib), or polypeptide-polypeptide drug complexes directly forming amide bond (related to polypeptide drugs such as p53 activated peptide, antibacterial peptide and polypeptide toxin) by solid phase synthesis, or a polypeptide-antibody drug complex by forming a disulfide bond (involving antibody drugs such as anti-PD-L1 antibody, rituximab, trastuzumab, cetuximab, bevacizumab, and the like), and the like.

After mn is connected with cysteine, the designed mn can be modified on high molecular carrier materials such as polyethylene glycol-distearoyl phosphatidyl ethanolamine (PEG-DSPE) containing maleimide functional groups, polyethylene glycol-polylactic acid (PEG-PLA), polyethylene glycol-lactic glycolic acid copolymer (PEG-PLGA) and polyethylene glycol-polycaprolactone (PEG-PCL), and can be used for constructing nano drug delivery systems such as mn-modified liposome, polymer micelle, polymer disc, nanoparticle, biomembrane coated nanoparticle and the like.

The mn-modified nano drug delivery system designed by the invention can entrap paclitaxel, docetaxel, captaxel, doxorubicin, epirubicin, camptothecin, hydroxycamptothecin, 9-nitrocamptothecin, vinblastine, vincristine, irinotecan, bortezomib, carfilzomib, parthenolide and derivatives thereof, imatinib, nilotinib, dasatinib, everolimus, erlotinib, sunitinib, sorafenib, ibrutinib, regorafenib, vemurafenib, olaparib, p53 activation peptide, melittin, scorpion venom peptide and other antitumor drugs; imaging substances such as coumarin 6, FITC, FAM, DiO, DiI, 5-TAMRA, 6-TET, HEX, 6-JOE, Rhodamine B, Rhodamine 6G, etc., near infrared dyes Cy3, Cy3.5, Cy5, Cy5.5, Cy7, IR783, IR820, DiR, DiD, Alexa Fluor 680, BIDIPY630/650-X, BIDIPY650/665-X, BIDIPY665/676, TO-PRO-3, TO-PRO-5, etc., chemiluminescent substances Luminol, isoluminol, AMPPD, CSPD, CDP-star, lucigenin, etc., magnetic resonance imaging agents Gd-DTPA, etc. may also be included.

The invention provides a material basis for mn preparation and property investigation and mn modified drug compound and nano drug delivery system for tumor diagnosis and treatment, and the test results show that mn can mediate in-vivo tumor active targeting, and compared with the existing ligand polypeptide c (RGDYK), the invention has better stability in serum and receptor protein α_vβ₃The combined activity is higher, and the immunogenicity of the nano-carrier system modified by the nano-carrier system is lower than that of the nano-carrier system modified by c (RGDyK) or RW, so that the mediated in vivo active targeting effect is better.

More specifically, the invention is realized by the following technical scheme:

1. synthesis of mn-Cys and fluorescent marker (mn-Fluorescein, RW-Fluorescein)

The mn-Cys is prepared by a solid-phase synthesis method, and the mn-Fluorescein is synthesized by Michael addition reaction of a maleimide group and a sulfhydryl group. HPLC and MS characterize the structure.

2. Polypeptide stability and receptor affinity evaluation

Serum stability from serum, with integrin α_vβ₃The combination ability and the cellular uptake ability of high expression of the protein are examined in three aspects, c (RGDyK) and RW. are compared, c (RGDyK), mn and RW are respectively incubated with mouse serum at 37 ℃, the concentration of the polypeptide is detected at different time points for comparison of stability, and c (RGDyK), mn and RW and integrin α are evaluated by surface plasmon resonance_vβ₃Comparing mn-Fluorescein, RW-Fluorescein and c (RGDyK) -Fluorescein pairs α_vβ₃The in vitro targeting of high-expression cells (such as umbilical vein endothelial cells HUVEC) and model tumor cells (such as brain glioma cells U87); comparing the uptake capacity of the in vitro 3D tumor sphere model for mn-fluoroescein, RW-fluoroescein, and c (RGDyK) -fluoroescein.

3. Preparation of polypeptide-imaging agent complexes

Connecting halfReacting the cystine-carried mn with maleimide DTPA to obtain mn-DTPA, and chelating Gd or Gd^99mTc is obtained as mn-DTPA-Gd or mn-DTPA-^99mTc。

4. Preparation of polypeptide-drug complexes

The mn after cysteine connection reacts with maleimide hexylhydrazine derivatives of drugs to form polypeptide-drug complexes containing pH sensitive hydrazone bonds, wherein the drugs comprise ketone or aldehyde group-containing drugs such as adriamycin and epirubicin;

the mn after cysteine connection reacts with a 3- (2-pyridinedimercapto) propionic acid derivative of a medicament to form a polypeptide-medicament compound containing a disulfide bond, wherein the related medicaments comprise medicaments containing hydroxyl or amino, such as paclitaxel, docetaxel, carboplatin, camptothecin, hydroxycamptothecin, 9-nitrocamptothecin, vinblastine, vincristine, irinotecan and the like;

mn reacts with boric acid groups of the drugs by modifying dopamine to form a polypeptide-drug compound containing pH sensitive borate, wherein the related drugs comprise drugs containing boric acid groups such as bortezomib;

mn is directly condensed with polypeptide drugs by solid phase synthesis to prepare fusion polypeptide, wherein the related drugs comprise p53 activated peptide, antibacterial peptide, polypeptide toxin and other polypeptide drugs;

mn forms a polypeptide-antibody complex with an antibody through a disulfide bond, wherein the related antibody comprises an anti-PD-L1 antibody, rituximab, trastuzumab, cetuximab, bevacizumab and other antibody drugs;

5. construction and characterization of mn-PEG-DSPE liposome drug delivery system

Firstly, synthesizing mn-modified high molecular material mn-PEG-DSPE, and realizing the synthesis of mn-PEG-DSPE through the reaction of free sulfydryl on the polypeptide connected with cysteine and maleimide contained in Mal-PEG-DSPE;

then preparing mn modified liposome (mn-LS), preparing liposome from certain amount of mn-PEG-DSPE, HSPC, cholesterol and medicine (FAM, DiR, DiD or DOX) by film forming method, and characterizing liposome particle size and particle size distribution by laser scattering particle size instrument.

Evaluation of in vivo and in vitro tumor targeting of mn-LS

Examine the uptake of mn-LS/FAM, RW-LS/FAM, c (RGDyK) -LS/FAM and mPEG-LS/FAM by U87 cells, HUVEC cells and U87 tumor extraspherical models;

respectively injecting mn-LS/DiR, RW-LS/DiR, c (RGDyK) -LS/DiR and mPEG-LS/DiR into the tail vein of a nude mouse with a loaded U87 subcutaneous transplantation tumor model, and comparing the intratumoral distribution of different groups at each time point;

mn-LS/DiD, RW-LS/DiD, c (RGDyK) -LS/DiD and mPEG-LS/DiD are injected into the tail vein of a nude mouse with a U87 subcutaneous tumor model respectively, the fluorescence intensity of each organ of different groups at each time point is measured, and the in-vivo distribution of different drug delivery systems at each time point is quantified.

Evaluation of in vivo antitumor Effect of mn-LS/DOX

The in vivo anti-tumor effect of different paclitaxel-loaded drug delivery systems is evaluated by respectively injecting mn-LS/DOX, RW-LS/DOX, c (RGDyK) -LS/DOX, mPEG-LS/DOX, daunorubicin hydrochloride DOX and normal saline into the tail vein of a nude mouse with a U87-loaded subcutaneous tumor model, and taking the tumor volume, the tumor weight, the apoptosis of tumor tissue cells, new blood vessels and the number of mimicry blood vessels as indexes.

The invention provides polypeptide mn and application thereof in tumor targeted diagnosis and treatment, in particular to a pharmaceutical composition modified by mn polypeptide and derivatives thereof and a modified drug delivery system, so as to realize targeted diagnosis and treatment of tumors; compared with the widely used integrin ligand c (RGDyK), mn and derivatives thereof have higher binding activity with integrin, and show better in vivo stability, thereby solving the problem that the multi-peptide is easy to degrade in blood to possibly cause the reduction of tumor targeting capability; the immunogenicity of the mn and derivative modified carrier system is lower than that of c (RGDyK) and RW modified carrier systems, so that the entrapped drug has better in-vivo tumor targeted drug delivery effect.

Drawings

FIG. 1 HPLC and ESI-MS profiles of mn-Cys

The chromatographic method comprises the following steps: chromatography column (YMC, C18): 150X 4.6 mm; mobile phase A: water (containing 0.1% trifluoroacetic acid), mobile phase B: acetonitrile (containing 0.1% trifluoroacetic acid); elution procedure: 0-45min 5% B-65% B; flow rate: 0.7 mL/min; column temperature: 40 ℃; and (3) detection: UV 214nm, retention time: and (5) 12 min. ESI-MS: 864.4, corresponding to the theoretical molecular weight.

FIG. 2 HPLC and ESI-MS profiles of RW-Cys

Chromatography method as above, retention time: and (5) 12 min. ESI-MS: 866.6, corresponding to the theoretical molecular weight.

FIG. 3 HPLC and ESI-MS profiles of mn-Fluorescein

Chromatography method as above, retention time: 17.2min, ESI-MS: 1291.4, corresponding to the theoretical molecular weight.

FIG. 4 HPLC and ESI-MS profiles of RW-Fluorescein

Chromatography method as above, retention time: 17.0min, ESI-MS: 1292.2, corresponding to the theoretical molecular weight.

FIG. 5, mn-PEG₃₄₀₀-DSPE、RW-PEG₃₄₀₀-DSPE and c (RGDyK) -PEG₃₄₀₀HPLC and of DSPE¹H-NMR spectrum

The chromatographic method comprises the following steps: chromatography column (Sepax, C4); mobile phase A: water (containing 0.1% trifluoroacetic acid), mobile phase B: acetonitrile (containing 0.1% trifluoroacetic acid); elution procedure: 0-45min 15% B-75% B; flow rate: 0.7 mL/min; column temperature: 40 ℃; and (3) detection: UV 214 nm. The Mal-PEG-DSPE retention time is 20.454min, while the polypeptide-PEG-DSPE retention time is obviously advanced;

the NMR spectrum of Mal-PEG-DSPE showed a maleimide peak at 6.7ppm, whereas the NMR spectrum of polypeptide-PEG-DSPE showed the disappearance of this peak, indicating that the maleimide group in Mal-PEG-DSPE had reacted to completion.

FIG. 6 serum stability of mn, RW and c (RGDyK)

The ordinate of the graph is the residual percentage of intact polypeptide, showing that the stability of RW and mn in 50% mouse serum is significantly higher than c (rgdyk), incubation for 12h, RW degradation 10%, mn degradation 25%; but c (RGDyK) was degraded by 50%.

FIG. 7, mn, RW and c (RGDyK) and α_vβ₃Binding activity of (2)

Shows that the dissociation patterns of the three polypeptides are similar, mn and RW with α_vβ₃Has a binding activity significantly stronger than that of c (A), (B), (C)RGDyK)，K_DThe values were 0.410. mu.M, 0.380. mu.M and 4.404. mu.M, respectively.

FIG. 8 uptake of Fluorescein-tagged polypeptide by brain glioma cells U87

The left and right images are confocal laser photographs and flow cytometric fluorescence detection results of fluoroescein-labeled mn, RW and c (rgdyk) after 4 hours of action with U87 cells, respectively, and show that the uptake of mn, RW and c (rgdyk) by U87 cells is significantly higher than that of free Fluorescein, and that the uptake of mn, RW and c (rgdyk) is not significantly different.

FIG. 9 uptake of Fluorescein marker polypeptide by umbilical vein endothelial cells HUVEC

The left and right panels are confocal images of lasers and flow cytometric fluorescence measurements of Fluorescein-labeled mn, RW and c (RGDyK) after 4h of interaction with U87 cells, respectively, showing that the uptake of mn, RW and c (RGDyK) by HUVEC cells is significantly higher than that of free Fluorescein, and that the uptake of c (RGDyK) is slightly stronger than that of mn and RW.

FIG. 10U 87 tumor sphere uptake of Fluorescein-tagged polypeptide

Shows that each fluoroescein marker polypeptide is taken up by U87 tumor spheres, and each fluoroescein marker polypeptide can be taken up by U87 tumor spheres well, and has obvious difference with FAM.

FIG. 11U 87 tumor sphere uptake after Fluorescein-tagged polypeptide crossing the blood-tumor barrier (BTB)

Shows the uptake condition of U87 tumor spheres after each Fluorescein labeled polypeptide crosses BTB barrier membrane, and each Fluorescein labeled polypeptide c (RGDYK) -Fluorescein, RW-Fluorescein and mn-Fluorescein can be well taken up by U87 tumor spheres after crossing BBTB barrier membrane, and has obvious difference with FAM.

FIG. 12 transportation of Fluorescein-tagged polypeptide across BTB barrier membranes

Mn-fluoroescein was shown to be the most efficient across BTB barrier membranes, and RW-fluoroescein was, secondly, slightly stronger than c (rgdyk) -fluoroescein.

FIG. 13, mn, RW and c (RGDyK) competitive inhibition assay results

Shows that c (RGDyK) inhibits mn and RW uptake, demonstrating that mn and RW are bound α_vβ₃The protein was taken up by U87 cells.

FIG. 14, mn, RW and c (RGDyK) cell-entering mechanism test results

It was shown that mn, RW and c (rgdyk) entry are most likely associated with macroencapsulation and probably clathrin-mediated endocytosis; and, mn entry mechanisms may be associated with caveolin-mediated endocytosis.

FIG. 15 uptake of FAM-loaded liposomes by glioma cells U87

Showing that each of the loaded FAM liposomes is taken up by U87 cells, c (RGDyK) -LS/FAM, RW-LS/FAM and mn-LS/FAM are all taken up well by U87 cells, and are clearly different from FAM and LS/FAM which is a non-target liposome.

FIG. 16 uptake of FAM-loaded liposomes by umbilical vein endothelial cells HUVEC

Showing that each of the loaded FAM liposomes was taken up by HUVEC cells, c (RGDyK) -LS/FAM, RW-LS/FAM and mn-LS/FAM were all taken up well by HUVEC cells, and were clearly different from FAM and LS/FAM, which are non-target liposomes.

FIG. 17 FAM liposome-loaded post-transmembrane blood-tumor barrier (BTB) U87 tumor sphere uptake

Shows that the uptake of U87 tumor spheres after each FAM-loaded liposome crosses the BTB barrier membrane, and c (RGDyK) -LS/FAM, RW-LS/FAM and mn-LS/FAM can be well taken by U87 tumor spheres after crossing the BTB barrier membrane, and are obviously different from the LS/FAM without target liposome.

FIG. 18 FAM-loaded liposomes transported across BTB barrier membranes

mn-LS/FAM was shown to be the most efficient across BTB barrier membranes, RW-LS/FAM was slightly weaker, and c (RGDyK) -fluoroescein was the least efficient across BTB barrier membranes.

FIG. 19 shows DiR liposome-loaded subcutaneous graft intratumoral distribution

Panel A is an in vivo fluorescence distribution image of 4h after tail vein injection, the PBS group, mPEG-LS/DiR, c (RGDyK) -LS/DiR, RW-LS/DiR and mn-LS/DiR are sequentially arranged from left to right, and panel B is a fluorescence distribution image of the viscera, which shows that mn modified liposome can be better targeted to the tumor site.

FIG. 20 shows the tissue distribution of nude mice model of subcutaneous tumor implantation with DiD liposomes

Panel A is tissue distribution data 2h after tail vein injection, showing that c (RGDyK) -LS/DiD liver and spleen accumulation is high, mn-LS/DiD is highest on tumor accumulation, and RW-LS/DiR is second; FIG. B is the tissue distribution data after 8h of tail vein injection, which shows that c (RGDyK) -LS/DiD still mostly distributes in the liver and spleen, and the tumor accumulation is less; mn-LS/DiD tumors accumulated most, RW-LS/DiR second; c, the blood concentration of (RGDyK) -LS/DiD is obviously reduced, which indicates that the long circulation effect of c (RGDyK) -LS/DiD is poor; and the graph C is the tissue distribution data after tail vein injection for 24h, and the distribution trend is consistent with that before.

FIG. 21 shows immunofluorescence analysis of DiD liposome-loaded subcutaneous tumor-transplanted model nude mouse tumor sections

Shows that c (RGDyK) -LS/DiD, RW-LS/DiD and mn-LS/DiD all have good effect on integrating with tumor tissue integrin protein α_vIntegrin protein β₃Tumor neovasculature (CD31 antibody marker) co-localisation, no target liposome LS/DiD co-localisation at all; the mn-LS/DiD tumor tissue accumulated the most and fluoresced the most.

FIG. 22 shows the tissue distribution and serum IgG concentration of nude mice model with subcutaneous transplantable tumor after multiple administration of DiD-loaded liposomes

The nude mice with the U87 subcutaneous tumor model are administered with the idle liposome modified by each target head for 4 times, and then are injected with the corresponding DiD-carrying liposome by tail vein for 2h, and then the distribution of each organ and the corresponding antibody concentration in serum are measured; the left graph is tissue distribution data after tail vein injection for 2h, which shows that c (RGDyK) -LS/DiD blood concentration is rapidly reduced, RW-LS/DiD blood concentration is also obviously reduced, and tumor accumulation is lower than mn-LS/DiD; the blood concentration corresponded to the highest IgG concentration in the c (RGDyK) -LS/DiD-administered group, the second highest IgG concentration in the RW-LS/DiD-administered group, and the lower level of antibody in the mn-LS/DiD-administered group (as shown in the right panel).

FIG. 23 immunofluorescence analysis of liver and tumor sections of nude mice model of subcutaneous transplantation tumor after multiple administration of DiD-loaded liposome

It was shown that c (RGDyK) -LS/DiD, RW-LS/DiD and mn-LS/DiD and the targetless liposome LS/DiD were phagocytosed by liver macrophages (labeled with F4/80 antibody), aggregated in the antrum hepaticum (Phalloidin labeled cytoskeleton, liposome red fluorescence aggregated in the liver parenchymal interstitial space); only c (RGDyK) -LS/DiD in the tumor section has better co-localization with tumor macrophages (marked by F4/80 antibody), which indicates that even if the tumor section is reached, the tumor section still can be cleared by the macrophages; indicating that mn-LS/DiD showed the lowest immunogenicity compared to liposomes modified with other polypeptides.

FIG. 24 shows the pharmacokinetic results in SD rats after multiple adriamycin-loaded liposomes

SD rats are administered with the empty liposomes modified by each target head for 2 times, and then injected with corresponding doxorubicin liposomes, and the change of blood concentration is observed, which shows that c (RGDyK) -LS/DOX is cleared fastest, RW-LS/DOX is cleared for times, mn-LS/DOX is cleared more slowly compared with the former results, and the results are consistent with the former results.

FIG. 25 shows particle size of Doxorubicin-loaded liposomes

Particle size pictures of the doxorubicin liposomes are shown, from top to bottom, as LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX and mn-LS/DOX, and there is no significant difference in the liposome size in each prescription.

FIG. 26 Adriamycin liposome-loaded in vitro inhibition U87 cell and HUVEC cell growth curves

Panel A and Panel B are plots of DOX, LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX, respectively, for the activity of U87 cells and HUVEC cells, and panel A shows LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX, respectively, after 4h of culture for U87 cells, and IC's for LS/DOX, C (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX₅₀3.55, 1.05, 1.58 and 1.15 μ M, respectively, and all four liposomes can inhibit the growth of U87 cells in vitro, wherein the in vitro cytotoxic activity of mn-LS/DOX, c (RGDyK) -LS/DOX is the best; panel B shows LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX IC after HUVEC cells were dosed for 4h and cultured for 72h₅₀Four liposomes inhibited HUVEC cell growth in vitro at 0.93, 0.19, 0.05 and 0.13. mu.M, respectively, with RW-LS/DOX and mn-LS/DOX exhibiting the best in vitro cytotoxic activity.

FIG. 27 results of in vitro inhibition of neovascularization by Doxorubicin-loaded liposomes

It is shown that DOX, LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX inhibit neovascularization in vitro models more significantly than c (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX.

FIG. 28, results of in vitro inhibition of mimetic angiogenesis by Doxorubicin-loaded liposomes

It is shown that DOX, LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX inhibit formation of mimicry extravascular models more significantly than c (RGDyK) -LS/DOX and RW-LS/DOX, mn-LS/DOX inhibit formation of mimicry vessels.

FIG. 29 shows the results of an doxorubicin-loaded liposome-loaded subcutaneous graft tumor suppression test

The left panel is a curve of tumor volume change of each group of nude mice with time, each administration group has inhibition effect on tumor growth compared with the normal saline group, RW-LS/DOX and mn-LS/DOX have significant difference compared with c (RGDyK) -LS/DOX (n is 7, p is 0.01), mn-LS/DOX has best in vivo efficacy; on the right panel, tumor tissues were weighed and statistically analyzed, showing that tumor weights in the RW-LS/DOX and mn-LS/DOX groups were significantly lower than those in the c (rgdyk) -LS/DOX (n-7, p <0.01), with the mn-LS/DOX group having the lowest tumor weight.

FIG. 30 shows the results of TUNEL assay

TUNEL staining showing that DOX, LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX, and mn-LS/DOX promote apoptosis in subcutaneous tumors, with apoptotic positive nuclei appearing tan or brownish.

Detailed Description

The invention will be further understood by reference to the following examples, but is not limited to the scope of the following description.

Example 1

Synthesis and characterization of polypeptide, polypeptide-Cys, polypeptide-Fluorescein, polypeptide-drug compound and polypeptide-PEG-DSPE

Synthesis and characterization of polypeptide and polypeptide-Cys:

an mn polypeptide (amino acid sequence mnRwr; upper case letters represent L-configuration amino acids, and lower case letters represent D-configuration amino acids) and a RW polypeptide (amino acid sequence RWrNM; upper case letters represent L-configuration amino acids, and lower case letters represent D-configuration amino acids) are designed and synthesized by a solid-phase polypeptide synthesis method.

The specific method comprises the following steps: by using a Boc solid-phase polypeptide synthesis method, amino acids are sequentially grafted on PAM-Boc resin in sequence, HBTU/DIEA is used as a condensing agent, and TFA is used as a deprotection agent for reaction. After the reaction was completed, the resin was cleaved with hydrogen fluoride containing P-cresol, and the reaction was stirred in ice bath for 1 h. And (3) after the reaction is finished, removing hydrogen fluoride in the tube under reduced pressure, precipitating with glacial ethyl ether, washing the precipitate for 3 times, dissolving the precipitate again with 20% acetonitrile, collecting filtrate, and performing rotary evaporation to obtain a crude polypeptide solution. The crude polypeptide was isolated and purified using acetonitrile/water (containing 0.1% TFA). HPLC and ESI-MS characterize the purity and molecular weight (Mw) of RW, RW-Cys, mn-Cys. The HPLC and mass spectrum of RW-Cys and mn-Cys are shown in figures 1 and 2.

Synthesis and characterization of polypeptide-Fluorescein:

dissolving RW-Cys and mn-Cys obtained in the above steps in 0.1M PBS (pH7.2), dissolving Fluorescein-5-maleimide in DMF, mixing, magnetically stirring for reaction, monitoring by HPLC, stopping reaction after RW-Cys and mn-Cys are completely reacted, purifying the prepared liquid phase, and separating and purifying with acetonitrile/water (containing 0.1% TFA) system. And freeze-drying to obtain the pure RW-fluorochein or mn-fluorochein. The HPLC chromatogram and the mass spectrogram are shown in figures 3 and 4.

Preparation of polypeptide-drug complexes:

examples of mn-doxorubicin complexes prepared as mn linked ketone or aldehyde containing drugs. 9.4mg of the thiolated mn polypeptide was dissolved in 3mL of phosphate buffer (0.1mM, pH 7.0), and 10-fold molar amount of tris (2-carboxyethyl) phosphine (TCEP) was added, followed by stirring at 4 ℃ for 20 min. Then 4 times of molar weight of adriamycin 6-maleimide hexylhydrazine derivative is added, and the reaction is carried out for 1 hour at room temperature in a dark place. Purifying the reaction liquid by using a preparation liquid phase, and freeze-drying to obtain the mn-adriamycin compound.

Examples of drugs containing hydroxyl or amino groups linked by disulfide bonds with mn-paclitaxel complexes as mn. Dissolving 200mg of paclitaxel in 10mL of chloroform, cooling to 0-5 ℃, adding 39.99mg of DCC and 60.4mg of 3- (2-pyridinedimercapto) propionic acid, heating to room temperature after adding materials, and reacting overnight. The reaction solution is filtered and purified by column chromatography (CHCl3/MeOH 50:1-15:1, V/V elution) to obtain the taxol 3- (2-pyridinedimercapto) propionic acid derivative. Dissolving a paclitaxel 3- (2-pyridinedimercapto) propionic acid derivative in 5mL of DMF (dimethyl formamide), dissolving mn-Cys with the molar weight being 1.5 times that of the solution in PBS/DMF, keeping the pH value of the solution at 4-5, dropwise adding the paclitaxel 3- (2-pyridinedimercapto) propionic acid derivative into a mercapto polypeptide solution, reacting for 6 hours at room temperature, preparing a liquid phase, purifying and freeze-drying to obtain a polypeptide-paclitaxel compound;

examples of mn-bortezomib complexes as mn linked boronic acid group containing drugs. Amino acids are sequentially inoculated on the resin according to the mn synthesis, and the Boc protection of the nitrogen removal end of trifluoroacetic acid is carried out after all amino acid residues of the polypeptide are inoculated. Adding DMF solution containing 3 times of succinic anhydride and DIEA, and reacting at room temperature for 30 min. After the resin is washed, 5 times of trimethylchlorosilane in molar weight is added to protect dopamine, HBTU/DIEA is used as a condensing agent, and the reaction is carried out for 1 hour at room temperature. The resin was cleaved with HF and purified by preparative HPLC to give the polypeptide-dopamine derivative. In a buffer solution with the pH value of 7.4, mixing the polypeptide-dopamine derivative and bortezomib in a molar ratio of 1:1 to obtain a polypeptide-bortezomib compound;

an example of a mn-PMI fusion polypeptide as the mn-linked polypeptide drug. Is directly prepared by a solid phase polypeptide synthesis method, and the specific method comprises the following steps: after the mn-PMI polypeptide sequence is determined, amino acids are sequentially accessed according to the method same as the preparation of mn, and the mn-PMI fusion polypeptide is obtained after HF cutting and purification;

the synthesis and characterization of polypeptide-PEG-DSPE:

the synthesis of the membrane material is realized through the reaction of free sulfydryl of the polypeptide and maleimide contained in Mal-PEG-DSPE. Dissolving 14mg polypeptide-Cys in PBS solution (0.1M, pH7.2), dissolving 40mg Mal-PEG-DSPE in 1.5ml DMF, slowly adding dropwise into PBS, mixing, stirring at room temperature for 2 hr, detecting reaction by HPLC, removing excessive polypeptide-Cys by dialysis, lyophilizing, HPLC and collecting the filtrate¹The H-NMR characterization is shown in FIG. 5.

Example 2

Serum stability Studies of Polypeptides

Preparing 1mg/mL aqueous solution of c (RGDyK), RW and mn, adding 0.1mL into 0.9mL of 25% mouse serum, incubating at 37 deg.C, taking out 100 μ L of reaction solution after 0.5, 1, 2, 4, 8 and 12h, adding 20 μ L of trichloroacetic acid (TCA) to precipitate proteins in serum, standing at 4 deg.C for 20min, centrifuging at 12000 rpm for 10min, and taking out 20 μ L of supernatant for HPLC analysis (as shown in FIG. 6).

Example 3

Polypeptide and integrin α_vβ₃Binding Activity test of

Recombinant human GRP78 was coupled to CM5 chips and RU values reached the target values. C (RGDyK), RW and mn were prepared as gradient sample solutions. Sample introduction is carried out from low to high in sequence, binding activities of c (RGDyK), RW and mn and protein are analyzed by Biacore T200Evaluation software, and K is calculated respectively_DValues (as shown in fig. 7).

EXAMPLE 4 in vitro cell Targeted validation of polypeptides

In vitro targeting of the polypeptide to glioma cells U87:

taking monolayer cultured glioma cells (U87 cells) of logarithmic growth phase, digesting the monolayer cultured cells with 0.25% trypsin, preparing single cell suspension with DMEM culture solution containing 10% fetal calf serum, and adding 1 × 10 per well⁵The individual cells were seeded in 12-well plates, 1mL per well volume, and the plates were transferred to a carbon dioxide incubator at 37 ℃ with 5% CO₂And after 24 hours of culture under the saturated humidity condition, preparing 5 mu M FAM, c (RGDyK) -fluoroescein, RW-fluoroescein and mn-fluoroescein solution by using a DMEM culture solution containing 10% fetal calf serum. Sucking out the culture solution from the culture plate, adding the above solutions, incubating at 37 deg.C for 4h, and removing the supernatant. Washing with PBS solution for three times, fixing cells with formaldehyde fixing solution, dyeing cell nucleus with DAPI, observing with laser confocal method, taking picture of cell internalization as the left figure of the attached drawing, washing with PBS for three times, analyzing with flow cytometry, and taking the result as the right figure of the attached drawing;

in vitro targeting of the polypeptide to umbilical vein endothelial cells HUVEC:

monolayer cultured umbilical vein endothelial cells (HUVEC cells) in logarithmic growth phase are taken, the experiment is carried out, and the internalization picture of the cells is shown in the left picture of the attached drawing. The flow cytometer analysis results are shown in the right picture of the figure.

Targeting of the polypeptide to an in vitro U87 tumor sphere:

adding 2% low molecular weight agarose solution into 48-well plate at 150 μ L per well, standing at room temperature, cooling, and solidifying400 μ L U87 cell suspension was seeded per well at a cell density of 2X 10³Per well. Placing in carbon dioxide incubator at 37 deg.C and 5% CO₂And culturing for 7 days under saturated humidity condition to form tumor balls. A5. mu.M solution of FAM, c (RGDyK) -fluoroescein, RW-fluoroescein and mn-fluoroescein was prepared in a DMEM medium containing 10% fetal bovine serum. The culture medium in the culture plate is sucked out, the solutions are respectively added, the culture plate is incubated for 4 hours at 37 ℃, and the supernatant is sucked away. Washing with PBS for three times, fixing with paraformaldehyde for 15min, and observing under a confocal microscope (shown in FIG. 10);

u87 tumor sphere uptake following crossing of the blood-tumor barrier (BTB) barrier membrane by the Fluorescein-tagged polypeptide:

adding 2% low molecular weight agarose solution into 48-well plate at 150 μ L per well, standing at room temperature, cooling, solidifying, inoculating 400 μ L U87 cell suspension per well, and making cell density 2 × 10³Per well. Placing in carbon dioxide incubator at 37 deg.C and 5% CO₂Culturing for 7 days under saturated humidity condition to form tumor balls;

HUVEC cells were digested with 0.25% trypsin, suspended in DMEM medium at 1X 10⁴Cell/well Density seeded in 24-well transwell Upper Chamber, U87 cell suspension at 5X 10⁴Inoculating the strain/hole density into a 24-hole transwell lower chamber, and culturing in an incubator for 3-5 days to obtain an in-vitro BTB model;

in the experiment, the tumor ball is transferred to a BTB model transwell lower chamber, 30 mu M of fluoroescein labeled polypeptide is added into an upper chamber, the tumor ball in the lower chamber is taken out after 4h, washed by PBS, fixed by paraformaldehyde, and then subjected to tomography observation under a laser confocal microscope (as shown in figure 11);

measurement of efficiency of transportation of fluoroescein-tagged polypeptides across BTB barrier membranes:

the BTB model was constructed as in the above experiment, 15. mu.M of fluoroescein-labeled polypeptide was added to the upper chamber, 300. mu.L of the culture medium was removed from the lower chamber at a specified time point, the fluorescence quantification was performed with a microplate reader, and the transport efficiency was calculated, with the results shown in FIG. 12;

competitive inhibition assay:

with 9 groups, each group was examined for 3-fold competitive inhibition, and the groups were blank control, FAM [ + c (RGDyK) ], c (RGDyK) -fluoroescein [ + c (RGDyK) ], RW-fluoroescein [ + c (RGDyK) ], mn-fluoroescein [ + c (RGDyK) ], respectively. The U87 cells were trypsinized and plated on 12-well plates and pre-treated at 4 ℃ for 20min, and the prepared c (RGDyK) solution (non-fluorescent label) was also pre-treated at 4 ℃. The c (rgdyk) solution was then incubated for 2h to saturate the receptor proteins on the cell surface. Then adding each polypeptide solution labeled by fluorescein, digesting with pancreatin after taking for 4h at 4 ℃, washing for 3 times by PBS, and measuring the cell intake amount by flow (as shown in figure 13);

investigating a polypeptide cell entry mechanism;

5000 cells per well of U87 were plated in 96-well plates, and on the second day, each of the cytostatic agents 10. mu.g/mLcohlorpromazine, 4. mu.g/mL colchicines, 10. mu.g/mL cyto-D, 5. mu.g/mL BFA, 5. mu.g/mL filipin, 10. mu.M NaN were added₃2.5mM methyl-bcycodextrin (M- β -CD), 200. mu.M monensin, 20. mu.M nocodazole, 200. mu.M genistein were incubated for 30min, then c (RGDyK) -fluoroescein, RW-fluoroescein and mn-fluoroescein were added and taken up at 37 ℃ for 4h, then fixed with 4% paraformaldehyde for 15min, stained with 1. mu.g/mL DAPI for 3min, and finally quantitated by fluorescence with a microplate reader (see FIG. 14).

Example 5 in vitro targeting of polypeptide-modified liposomes

Preparation of FAM-loaded liposomes:

taking mn-liposome as an example, the prescription composition is HSPC/Chol/mPEG₂₀₀₀-DSPE/mn-PEG₃₄₀₀DSPE (52:43:3:2, mol/mol). Weighing the membrane material, dissolving in chloroform, performing reduced pressure rotary evaporation to remove the chloroform, and vacuum drying the obtained uniform lipid membrane overnight. Adding 2mg/mL FAM aqueous solution, and carrying out water bath shaking at 60 ℃ for 2h for hydration to obtain liposome suspension. Liposomes were extruded through 400, 200, 100 and 50nm nuclear pore membranes in sequence using a micro-extruder at a temperature of 60 ℃ to make the liposome particle size uniform. Separating and removing unencapsulated FAM by using normal saline as eluent through a sephadex G-50 column to obtain FAM-entrapped liposome;

glioma cell U87 uptake assay for polypeptide-modified liposomes:

number of pairs of studentsLong-term monolayer cultured glioma cells (U87 cells), digesting the monolayer cultured cells with 0.25% trypsin, preparing a single cell suspension with DMEM culture medium containing 10% fetal bovine serum, and culturing the cells in the presence of 10% fetal bovine serum⁴The density of individual cells/well was plated on a co-focusing dish and incubated overnight. 5 μ M of FAM, c (RGDyK) -LS/FAM, RW-LS/FAM and mn-LS/FAM solutions were prepared in DMEM medium containing 10% FBS, and the medium in the plate was aspirated, the solutions were added, incubated at 37 ℃ for 4 hours, and the supernatant was aspirated. PBS was washed three times, fixed in paraformaldehyde for 15min, stained with DAPI, and observed under a confocal microscope (as shown in FIG. 15).

Uptake experiments of polypeptide-modified liposomes by umbilical vein endothelial cells HUVEC:

monolayer cultured human umbilical vein endothelial cells (HUVEC cells) in logarithmic growth phase were taken and subjected to the same experiment as above, and the cell internalization photograph is shown in FIG. 16;

uptake of U87 tumor spheres after the polypeptide-modified liposomes crossed the BTB barrier membrane:

in the experiment, the tumor ball is transferred to a BTB model transwell lower chamber, each liposome solution loaded with 30 mu M is added into an upper chamber, the tumor ball in the lower chamber is taken out after 4 hours, PBS is used for rinsing, paraformaldehyde is fixed, and then tomography observation is carried out under a laser confocal microscope, and the picture is shown in figure 17;

detection of transport efficiency of polypeptide modified liposome across BBTB barrier membrane:

the BTB model was constructed as in the above experiment, with 20 μ M of each liposome solution loaded in the upper chamber, and 300 μ L of the culture medium in the lower chamber at the specified time point was removed, and the transfer efficiency was calculated by fluorescence quantification using a microplate reader, the results of which are shown in fig. 18.

Example 6 in vivo targeting validation of polypeptide-modified liposomes

Preparation of DiR-loaded liposomes and DiD-loaded liposomes:

mn-LS/DiR or mn-LS/DiD was prepared in a manner similar to mn-LS/FAM except that the DiR dye was added dissolved in chloroform together with the lipid material;

in vivo targeting verification of the polypeptide modified liposome:

respectively injecting PBS, LS/DiR, c (RGDyK) -LS/DiR, RW-LS/DiR and mn-LS/DiR with the same fluorescence intensity into tail vein, anesthetizing the mice at 2, 4, 6, 8 and 10h after injection, recording the distribution of DiR fluorescence in the nude mice by using a living body imager and carrying out fluorescence semiquantitative calculation (as shown in figure 19);

and (3) detecting the tissue distribution of the polypeptide modified liposome:

respectively injecting PBS, LS/DiD, c (RGDyK) -LS/DiD, RW-LS/DiD and mn-LS/DiD with the same fluorescence intensity into tail vein, killing mice at 2, 8 and 24h after injection, taking blood, heart, liver, spleen, lung, kidney, brain and tumor, weighing, adding 1mL of distilled water, homogenizing tissues, measuring by an enzyme labeling instrument, and quantifying fluorescence (as shown in figure 20);

immunofluorescence analysis of tumor sections:

tumor tissues of each group of mice in the experiment are taken, sliced, labeled with CD31 antibody, and alpha is used for tumor neovascularization_vAntibody labeling alpha_vProtein, using β₃Antibody label β₃A protein; the laser confocal microscope was used to observe the co-localization of LS/DiD, c (RGDyK) -LS/DiD, RW-LS/DiD or mn-LS/DiD to characterize targeting in vivo (see FIG. 21).

Example 7 immunogenicity testing of polypeptide-modified liposomes

And (3) detecting the tissue distribution and serum IgG concentration of the polypeptide modified liposome after multiple times of administration:

after 4 times of administration of each unloaded liposome to nude mice with a model of subcutaneous tumor with lotus U87, blood is taken from the orbit, and serum is taken for measuring the concentration of anti-liposome IgG; then injecting the corresponding group of DiD liposome into tail vein, killing mice after 2h, taking blood, heart, liver, spleen, lung, kidney, brain and tumor, weighing, adding 1mL of distilled water, homogenizing, measuring by enzyme-labeling instrument, and quantifying fluorescence (as shown in the left picture of FIG. 22);

measuring serum IgG concentration by adopting an ELISA method, diluting the unloaded liposome of each group by using absolute ethyl alcohol, coating the diluted unloaded liposome in a 96-well plate overnight, washing the diluted unloaded liposome by using 0.05 percent Tween/PBS, and adding 1 percent BSA to block redundant sites; then diluting the serum of the corresponding group into gradient concentration, adding the serum to incubate at 37 ℃ for 30min, washing the serum by 0.05 percent Tween/PBS, adding Peroxidase-Conjugated affinity needle Goat Anti-Mouse IgG (H + L) to mark the antibody connected on the plate, and measuring the ultraviolet absorption of the antibody after the antibody is developed by TMB (as shown in the right graph of FIG. 22);

immunofluorescence analysis of polypeptide-modified liposomes in tumors and livers after multiple administrations:

in the experiment, liver and tumor tissues of each group of mice carrying DiD liposome are sliced, then Alexa 488-phaloidin is used for marking a liver cytoskeleton, and F4/80 antibody is used for marking liver and tumor tissue macrophages; confocal laser microscopy was used to observe LS/DiD, c (RGDyK) -LS/DiD, RW-LS/DiD or mn-LS/DiD and their co-localization to characterize the immune clearance in vivo (as shown in FIG. 23);

further, pharmacokinetic studies of polypeptide-modified liposomes after multiple administrations were performed.

Example 8 in vitro pharmacodynamic assay of polypeptide-modified DOX-loaded liposomes

Preparation and characterization of DOX-loaded liposomes:

the prescription of the liposome membrane material is consistent with mn-LS/FAM, after a vacuum-dried uniform lipid membrane is obtained, 0.16M ammonium sulfate solution is added, water bath oscillation is carried out for 2h at the temperature of 60 ℃, and the obtained liposome suspension is extruded on a micro extruder to pass through 400 nm, 200 nm, 100 nm and 50nm nuclear pore membranes. And (3) taking physiological saline as eluent, passing the homogenized blank liposome through a Sephadex G-50 gel column, and then mixing the purified blank liposome with the normal saline in a drug-lipid ratio of 1: adding adriamycin normal saline solution at 10(w/w), and shaking in water bath at 60 deg.C for 20 min. Free doxorubicin was removed by elution through a Sephadex G-50 gel column. The particle size characterization is shown in figure 25.

Polypeptide modified LS/DOX in vitro efficacy test:

at 4.0 × 10³Inoculating U87 cells into a 96-well plate, sucking out a culture solution after 24h, adding 200 mu L of a series of DOX, LS/DOX, c (RGDyK) -LS/DOX, RW-LS/DOX and mn-LS/DOX with concentration, co-culturing for 72h, adding MTT solution, continuously culturing for 4h, discarding the culture solution, adding 150 mu L of DMSO, shaking until purple particles are dissolved, measuring an absorbance value at 590nm by using a microplate reader, measuring the cell survival rate by using an MTT method, and calculating the cell survival rate and half lethal dose (as shown in figure 26);

polypeptide-modified LS/DOX inhibition of neovascularization assay:

adding 50 μ L matrigel into each well of 24-well culture plate, spreading in 24-well culture plate, and incubating in 37 deg.C incubator for 30min until it is solidified. 0.25% pancreatin digested HUVEC cells, 1 μ M DOX in each liposome solution or free DOX solution in DMEM culture to make single cell suspension, 1 × 10 per well⁵The individual cells were seeded in 24-well plates at 37 ℃ with 5% CO₂And observing the formation of a blood vessel-like structure after culturing for 12h under the saturated humidity condition (as shown in figure 27);

polypeptide-modified LS/DOX inhibition of formation of mimicry vessels:

adding 50 μ L matrigel into each well of 24-well culture plate, spreading in 24-well culture plate, and incubating in 37 deg.C incubator for 30min until it is solidified. 0.25% pancreatin digested U87 cells, 1 μ M DOX in each liposome solution or free DOX solution in DMEM culture to make single cell suspension, 1 × 10 per well⁵The individual cells were seeded in 24-well plates at 37 ℃ with 5% CO₂And formation of vessel-like structures was observed after 12h incubation under saturated humidity conditions (as shown in FIG. 28).

Example 9 in vivo pharmacodynamic assay of polypeptide-modified DOX-loaded liposomes

In vivo pharmacodynamic assay of polypeptide-modified LS/DOX:

the constructed U87 subcutaneous tumor animal model has the tumor size of 100mm³At that time, the test is performed in groups. Subcutaneous tumor model rat tail vein was injected with normal saline, DOX, LS/DOX, c (RGDyK)LS/DOX, RW-LS/DOX and mn-LS/DOX. The total adriamycin administration dose of the administration group is 10mg/kg and divided into five times, the administration interval of each time is two days, the major diameter (a) and the minor diameter (b) of the tumor are measured by a vernier caliper every other day, the tumor volume of each group of nude mice is calculated according to a formula, a change curve of the tumor volume along with time is drawn, and the statistical difference of each group is calculated. Tumor volume was calculated according to the following formula:

V_{tumor volume}＝0.5(a×b²)

16 days after dosing, all nude mice were sacrificed by cervical dislocation, subcutaneous tumors were taken and weighed, and statistical differences were calculated for each group (as shown in fig. 29);

and (3) detecting the apoptosis of the LS/DOX modified by the polypeptide:

on the 14 th day after the administration, tumor-bearing nude mice were sacrificed and tumor tissues were taken out and fixed, frozen sections were prepared, and tumor apoptosis was detected by TUNEL method, which detects the degree of apoptosis of tumor cells by Terminal Deoxynucleotidyl Transferase (TDT) -mediated dUTP nick end labeling (TUNEL). The method mainly comprises the following steps: paraffin sections were dewaxed conventionally to water; rinsing with PBS for 3 times, each for 3 min; 0.3% H₂O₂Treating the solution at room temperature for 20 min; digesting by 20 mu g/mL proteinase K at 37 ℃ for 20 min; rinsing with PBS for 3 times, each for 3 min; adding 30 μ L TUNEL mixed solution (TDT and biotin-dNTP) dropwise into each slice, and incubating at 37 deg.C for 60 min; the positive result is that the cell nucleus is in brown yellow or brown, the cell nucleus is judged to be apoptotic cell if brown particles in the cell nucleus are positive, the number of the positive cells is counted by continuously observing 5 high-power visual fields under a common optical microscope, the percentage of the number of the positive cells in the visual fields is the apoptosis index, and the result is shown in figure 30.

Claims

1. Polypeptide mn and its derivatives capable of targeting integrin, characterized in that the amino acid sequence thereof is mnRwr, wherein capital letters represent L configuration amino acids and lowercase letters represent D configuration amino acids.

2. The integrin-targetable polypeptide mn and derivatives thereof of claim 1, wherein the polypeptide mn and derivatives thereof are thiolated and then reacted with an imaging substance containing a maleimide group to obtain mn-X complexes.

3. The integrin-targetable polypeptide mn and its derivatives of claim 2, wherein in said mn-X complex, X is a fluorescent substance selected from FITC, FAM, 6-TET, 5-TAMRA, HEX, 6-JOE, or a near infrared dye selected from Cy3, Cy3.5, Cy5, Cy5.5, Cy7, IR783, IR820, DiR, DiD, BIDIPY630/650-X, BIDIPY650/665-X, BIDIPY665/676, TO-PRO-3, TO-PRO-5, or a chemiluminescent substance selected from lumine, isoluminol, AMPPD, CSPD, CDP-star, lucigenin, or a magnetic resonance imaging agent Gd-DTPA, or a radioimaging agent selected from luminission agents^99mTc-DTPA、¹⁸F-FDG、¹⁸F-Al-NOTA、¹⁸F-Al-DOTA、⁶⁸Ga-NOTA、⁶⁸Ga-DOTA、¹¹¹In-DTPA。

4. The polypeptide mn and its derivatives of claim 1, wherein the polypeptide mn and its derivatives are linked to therapeutic drugs via a pH-sensitive hydrazone bond, a pH-sensitive boronic acid lipid bond, or a disulfide bond, or directly condensed with polypeptide drugs to form fusion polypeptides, thereby obtaining mn-Y complexes.

5. The integrin-targetable polypeptide mn and its derivatives according to claim 4, wherein in the mn-Y complex, Y is an antitumor anthracycline drug selected from doxorubicin, epirubicin, or a taxane drug selected from paclitaxel, docetaxel, captaxel, or a camptothecin drug selected from camptothecin, hydroxycamptothecin, 9-nitrocamptothecin, irinotecan, or a vinblastine drug selected from vinblastine, vincristine, or a proteasome inhibitor drug bortezomib, or an antitumor stem cell drug parthenolide and its derivatives, or a molecular targeting drug selected from imatinib, nilotinib, dasatinib, everolimus, erlotinib, sunitinib, sorafenib, ibrutinib, regorafenib, williamib, olaparib, or a polypeptide drug, selected from p53 activating peptide, melittin, scorpion venom peptide, or antibody drug, selected from rituximab, bevacizumab, trastuzumab, cetuximab, pertuzumab, ipilimumab, and nivolumab.

6. The integrin-targetable polypeptide mn and its derivatives of claim 1, wherein said polypeptide mn and its derivatives are thiolated and then linked to a maleimide polyethylene glycol-Z complex to obtain mn-polyethylene glycol-Z complex.

7. The integrin-targetable polypeptide mn and its derivatives of claim 6, wherein in the mn-PEG-Z complex, Z is phospholipid, polylactic acid (PLA), poly (lactic-co-glycolic acid) (PLGA) or Polycaprolactone (PCL).

8. The integrin-targetable polypeptide mn and derivatives thereof of claim 7, wherein the mn-peg-phospholipid complex is used in the preparation of liposomal, micellar, disc, or biofilm-coated nanoparticle delivery systems.

9. The integrin-targetable polypeptide mn and its derivatives of claim 8, wherein the mn-polyethylene glycol-polylactic acid complex, mn-polyethylene glycol-lactic glycolic acid copolymer complex, mn-polyethylene glycol-polycaprolactone complex is used for preparing micelle drug delivery system or nanoparticle drug delivery system.

10. The integrin-targetable polypeptide mn and derivatives thereof of claim 8 or 9, wherein the liposomal delivery system, micellar delivery system, disc delivery system, nanoparticle delivery system, and biofilm-coated nanoparticle delivery system are used to entrap a diagnostic agent.

11. The integrin-targetable polypeptide mn and derivatives thereof of claim 10, wherein the diagnostic drug encapsulated by the delivery system is a fluorescent substance: coumarin 6, FITC, FAM, DiI, Rhodamine B, Rhodamine 6G, 5-TAMRA, 6-TET, HEX, 6-JOE, near-infrared dyes: cy3, Cy3.5, Cy5, Cy5.5, Cy7, IR783, IR820, DiR, DiD, Alexa Fluor 680, BIDIPY630/650-X, BIDIPY650/665-X, BIDIPY665/676, TO-PRO-3, TO-PRO-5, chemiluminescent substance: luminol, isolutenol, AMPPD, CSPD, CDP-star, lucigenin, magnetic resonance imaging agent Gd-DTPA, used for the image diagnosis and tracing of high expression integrin tumor.

12. The integrin-targetable polypeptide mn and derivatives thereof of claims 8 and 9, wherein the liposomal delivery system, micellar delivery system, disc delivery system, nanoparticle delivery system, and biofilm-coated nanoparticle delivery system are used to encapsulate an anti-tumor drug.

13. The integrin-targetable polypeptide mn and derivatives thereof of claim 12, wherein the antineoplastic drug entrapped in the delivery system is an anthracycline: doxorubicin, epirubicin, taxanes: paclitaxel, docetaxel, carboplatin, camptothecin drugs: camptothecin, hydroxycamptothecin, 9-nitrocamptothecin, irinotecan, vinblastine drugs: vinblastine, vincristine, proteasome inhibitors: bortezomib, carfilzomib, anti-tumor stem cell drugs: parthenolide and derivatives thereof, molecular targeted drugs: imatinib, nilotinib, dasatinib, everolimus, erlotinib, sunitinib, sorafenib, ibrutinib, regorafenib, vemurafenib, olaparib, or a polypeptide drug: p53 activating peptide, melittin, scorpion venom peptide.