RU2377247C2 - Molecular conjugate on basis of synthetic analogues of luliberin and application thereof as dna delivery system to cells of hormone-sensitive tumours (versions) - Google Patents

Abstract

FIELD: pharmacology.

SUBSTANCE: invention refers to medicine and can be used as an effective remedy for precise delivery of DNA complexes with molecular conjugates to certain organs and tissues in mammals. The technical effect is ensured by introduction of modified nuclear localisation signal (NLS) that shall allow for conjugates to form complexes with plasmid DNA containing a suicidal gene, and also shall provide higher conjugate concentration in tumour cell nuclei that leads to intensification of cytotoxic properties of doxorubicine.

EFFECT: higher effectiveness of tumour cell exposure.

3 cl, 5 dwg, 6 ex

Description

The invention relates to medicine and can be used as an effective means of targeted delivery of DNA complexes with molecular conjugates to certain organs and tissues of mammals. The main problem of gene therapy of tumor diseases is the development of effective means of delivery (DM) of genetic constructs to target cells. It is important that diabetes have the targeted effect, are not toxic and immunogenic to the body, and do not cause side effects. At the moment, there are no optimal diabetes "treating" genes that fully comply with the above requirements. It may be successful to use non-viral carriers for the delivery of foreign genetic constructs to cells that can be used repeatedly, because, unlike viral diabetes, they are less toxic and practically do not cause an immune response.

The most popular approach in this area is the use of molecular conjugates consisting of a cationic carrier for DNA condensation due to electrostatic interactions and a ligand part interacting with cellular receptors and ensuring targeted delivery of DNA complexes with molecular conjugates to certain mammalian organs and tissues [1].

Receptors for luliberins are normally presented on a very limited number of human tissues (pituitary, gonads). However, it has been shown that a number of human tumors, mainly carcinomas, synthesize a significant number of luliberin receptors. This circumstance makes these receptors attractive for targeted delivery of biologically active molecules to tumor cells [2]. The use of luliberins for targeted chemotherapy of hormone-sensitive tumors is widely used in the clinical practice of several countries.

It is known to use conjugates of luliberin analogues with various cytotoxic agents (melphalan, daunomycin, ribosome inhibitors) to sterilize animals and combat hormone-dependent human diseases (including hormone-sensitive tumors) [3].

The technical solution described in this patent consists in the use of luliberin analogues for targeted delivery of biologically active molecules to cells with a high level of GnRH receptors. The disadvantages of the described solution include the impossibility of forming complexes of plasmid DNA with molecular conjugates based on luliberin analogues and their targeted delivery to tumor cells.

The invention is known [4], which discusses the development of structures of analogues of luliberin — agonists and antagonists of luliberin receptors covalently linked to various cytotoxic agents, including doxorubicin. Within the framework of this approach, the possibilities related to the synthesis of NLS-GnRH molecular conjugates capable of forming complexes with plasmid DNA and targeted delivery to tumor cells expressing luliberin receptors have been unrealized.

Known conjugate of analogues of luliberin [5], the closest to the proposed invention, which is used in conjunction with the cytotoxic agent doxirubicin and its derivative for the treatment of hormone-sensitive tumors.

A disadvantage of the known conjugate with agents is the relatively low efficiency of exposure to tumor cells.

The technical result of the claimed invention is to increase the effectiveness of exposure to tumor cells.

The specified technical result in the present invention is achieved by introducing a modified nuclear localization signal (NLS), which will allow conjugates to form complexes with plasmid DNA containing a suicide gene, and will also provide a higher concentration of the conjugate in the nuclei of tumor cells, which, as shown by the results of numerous studies carried out in laboratory conditions of St. Petersburg State University, leads to increased cytotoxic properties of doxorubicin. The specified technical result is achieved by two variants of the claimed molecular conjugate.

The specified technical result according to the first embodiment is achieved by the fact that in a molecular conjugate based on synthetic analogues of luliberin, which includes a cationic component, which is a modified nuclear localization signal of the SV40 virus T-antigen, used to condense plasmid DNA, and a ligand component for interaction with tumor-specific receptors in accordance with the claimed invention as the ligand component use synthetic analogues of luliberin with the formula XR ¹ -His-R ³ -Ser-R ^5- D-Lys-Leu-Arg-Pro-R ¹⁰ where R ¹ is pGlu; R ³ is Trp, D-Trp, Pro or D-Pal (3); R ⁵ is Tyr or Arg; R ¹⁰ is Gly-NH ₂ , D-Ala-NH ₂ or NH-CH ₂ -CH ₃ ; X is a hydrogen atom or a lower alkanoyl group (C ₂ -C ₃ ) with luliberin receptor agonist activity, and the cationic component of the conjugate has the structure H-Pro-Lys-Lys-Lys-Arg-Lys-Val and is attached to the ligand component through e the amino group D-Lys (R ⁶ ).

In addition, this technical result is achieved by the fact that the obtained molecular conjugate system is used as a means of delivering DNA to hormone-sensitive tumor cells.

The specified technical result according to the second embodiment is achieved by the fact that in a molecular conjugate based on synthetic analogues of luliberin, which includes a cationic component, which is a modified nuclear signal of the SV40 virus T-antigen, used to condense plasmid DNA, and a ligand component for interaction with tumor-specific receptors in accordance with the claimed invention as the ligand component use synthetic analogues of luliberin with the formula HD-Lys-Pro-Gly-R ² -R ^3- Ser-Tyr-R ⁶ -Leu-Arg-Pro-R ¹⁰ -NH ₂ , where R ² is an aromatic D-amino acid; R ³ is Trp, D-Trp, Pro or D-Pal (3); R ⁶ is a D-amino acid; R ¹⁰ is Gly-NH ₂ or D-Ala-NH ₂ having luliberin receptor antagonist activity, and the cationic component of the conjugate has the structure H-Pro-Lys-Lys-Lys-Arg-Lys-Val and is attached to the ligand component via s- the amino group of the N-terminal D-Lys.

In addition, this technical result is achieved by the fact that the obtained molecular conjugate system is used as a means of delivering DNA to cells of hormone-sensitive tumors.

The claimed invention was tested at St. Petersburg State University in the laboratory of embryology, and the results of the tests below are specific examples of implementation of the first and second proposed variants of the invention.

Examples of specific implementation.

The synthesized molecular conjugates of NLS-LHRH:

as well as their fluorescently labeled derivatives.

Examples of the first option

Example 1

In experiments on the competitive displacement of labeled conjugates from the surface of HepG2 human hepatoma cells with molar excesses of unlabeled luliberin analogs, the receptor-mediated nature of the interaction of these molecular conjugates with tumor cells is shown (Figure 1, which shows the effect of excess synthetic luliberin analogs (V-7 and alarelin) on the binding of fluorescently labeled NLS-LHRH to HepG2 cells). 5 μg NLS-LHRH-F and the indicated molar excesses of unlabeled V7 or alarelin were added to HepG2 cells (30 mm dishes). Incubation was carried out for 4 hours at 4 ° C. Washed 5 times with cold PBS, left for 10 min in 0.5% albumin on PBS at 4 ° C, lysed, and fluorescence was measured. The fluorescence values were aligned with the concentration of cell protein. White columns correspond to competition with V7 peptide, and dark columns correspond to competition with alarelin peptide.

Example 2

The stoichiometry of DNA / NLS-LHRH complexes was investigated by purification of the complexes prepared in the presence of saturating amounts of NLS-LHRH (ten-fold excess in charges) from the unbound peptide by ultrafiltration. As a result, a complex containing saturating amounts of the peptide was isolated. It is known that heparin, being a stronger polyanion than DNA, is able to displace it from the complex with polycations [8, 9]. The DNA content in the isolated complex was determined spectrophotometrically after its complete destruction by an excess of heparin. The peptide content in the studied complex was determined by reverse titration with heparin. For this purpose, a calibration curve was constructed (Fig. 2a) for the dependence of the amount of heparin sufficient for complete destruction of the DNA / NLS-LHRH complex on the peptide content in the reaction medium during the formation of the complexes. The abscissa axis shows the excess of positive charges in the complex relative to negative DNA charges, and the ordinate shows the amount of heparin (μg) necessary for complete destruction of the complex containing 1 μg of DNA. Figure 2 (b) shows the results of titration of NLS-LHRH in the DNA / NLS-LHRH complex

(1 μg DNA), prepared with saturating amounts of NLS-LHRH and purified from unbound peptide by heparin ultrafiltration by gel retardation. 1 - pCMVluc; 2 - without heparin; 3rd 0.292 mcg heparin; 4 - with 0.4 μg of heparin; 5 - with 0.52 μg of heparin; 6 - with 0.65 μg of heparin; 7 - with 0.975 μg of heparin; 8 - with 1.46 μg of heparin; 9 - with 2.19 μg of heparin; 10 - with 3.29 μg of heparin. Asterisks in Figures 2a and 2b mark the position on the calibration curve corresponding to the complete destruction of the complex by heparin (a), and the experimental point corresponding to the complete destruction of the complex by heparin, detected by gel retardation (b). It was found that the maximum possible content of NLS-LHRH in the complexes corresponds to a 1.5-fold excess of positive NLS-LHRH charges relative to negative DNA charges. Similar results were obtained by us earlier for DNA complexes with the TAT peptide [8] and K8 [9].

The following examples 3, 4, 5 are common to the first and second variants of the claimed invention.

Example 3

The internalization of DNA complexes with fluorescently labeled molecular conjugates NLS-LHRH (option 1) and Nuk-1 (option 2) was studied by confocal microscopy. Cells were incubated with complexes prepared at a DNA: peptide charge ratio of 1: 1 (10 μM) for 2 h, fixed with 4% formaldehyde, additional DAPI staining was performed and analyzed by confocal laser fluorescence microscopy. The results are presented in Figure 3: a - HepG2 cells after incubation with DNA complexes with the molecular conjugate NLS-LHRH (option 1); b - HepG2 cells after incubation with DNA complexes with the Nuk-1 molecular conjugate (option 2); c - human fibroblasts after incubation with DNA complexes with the molecular conjugate NLS-LHRH (option 1); g - human fibroblasts after incubation with DNA complexes with the molecular conjugate Nuk-1 (option 2). Both complexes (DNA / NLS-LHRH and DNA / Nuk-l) were detected in the endosomes of human HepG2 hepatoma cells ((contain luliberin receptors), but not in human fibroblasts (do not contain luliberin receptors). The obtained results support receptor-mediated endocytosis as the main route of penetration into the cells of DNA complexes with the molecular conjugates NLS-LHRH and Nuk-1.

Example 4

The ability of NLS-LHRH (option 1) and Nuk-1 (option 2) to deliver DNA to HepG2 cells was tested using a luciferase test. Cells were transfected with complexes of plasmid pCMVluc containing a reporter gene encoding luciferase, under the control of a promoter of early human cytomegalovirus genes, with NLS-LHRH and Nuk-1 conjugates. Both complexes turned out to be transfectionally active. Figure 4 shows the effect of excess alarelin on the efficiency of transfection of HepG2 cells with pCMVluc / NLS-LHRH and pCMVluc / Nuk1 complexes (luciferase test). Light columns correspond to NLS-LHRH (option 1), dark columns correspond to Nuk-1 (option 2). The abscissa axis indicates molar excesses of alarelin, and the ordinate axis shows luciferase activity in relative light units. Adding during the incubation of cells with complexes of excess alarelin led to a decrease in the level of expression of the transferred gene using NLS-LHRH, but did not affect the transfection of cells with pCMVluc / Nuk-1 complex. Based on the data obtained, it can be concluded that the penetration of DNA complexes with NLS-LHRH into cells occurs according to the same mechanism as the internalization of free LHRH - receptor-mediated endocytosis.

Based on the data obtained, it can be concluded that both variants of the molecular conjugate are able to efficiently deliver DNA to human HepG2 hepatoma cells. Penetration of DNA complexes with NLS-LHRH into cells occurs by the same mechanism as the internalization of free LHRH - receptor-mediated endocytosis.

Example 5

The obtained data on the receptor-mediated nature of the penetration of DNA complexes with a molecular conjugate into HepG2 cells allowed us to go on to simulate the "suicidal" gene therapy of tumors by transferring the expression vector of the thymidine kinase virus HSV1 (rRTK1) into the cells, followed by treatment of the transfected cells with acyclovir. HepG2 cells were transfected with pPTK1 / NLS-LHRH (first variant) and pPTK1 / Nuk1 (second variant) complexes prepared at a charge ratio of 1: 1. 2 hours after transfection, acyclovir was added to the medium to a concentration of 50 μg / ml. After 24 hours, the cells were washed with phosphate-buffered saline, fixed with cold 70% ethanol, stained with propidium iodide (70 μM in 40 mm sodium citrate (pH 7.4)) for 1 hour at 37 ° C in the presence of RNase A (500 μg / ml). Figure 5 shows the analysis of the distribution of HepG2 cells in the phases of the cell cycle by flow cytometry: a - intact cells (control); b - cells after treatment with acyclovir (50 μg / ml) for 24 hours; c - cells transfected with pPTK1 / NLS-LHRH complexes after treatment with acyclovir (50 μg / ml) for 24 hours; d - cells transfected with pPTK1 / Nuk1 complexes after treatment with acyclovir (50 μg / ml) for 24 hours. Treatment of cells transfected with pPTKl / NLS-LHRH complexes with acyclovir resulted in the complete disappearance of cells in the G2 and S phases of the cell cycle and almost complete the disappearance of cells in phase G1. More than 90% of the cell population went into apoptosis (Figv). In the case of using the Nuk1 conjugate (Fig. 5 g), cell death was also observed, but the effect was less pronounced, since about 15% of the cells remained in the G1 phase. Cells in phases S and G2 were also absent. Apoptosis of the cells is caused precisely by the expression of the "suicide" gene, since treatment of intact HepG2 cells with acyclovir (Fig.5b) did not lead to a significant deviation of the cell cycle compared to the control (Fig.5a).

Example 6

Synthesis of molecular conjugate (first and second options).

Synthesis

The molecular conjugate NLS-LHRH (first option) and Nuk1 (second option) were synthesized on a 4-methylbenzhydrylamino polymer with an amino group content of 0.62 mmol / g. Prior to the addition of the Fmoc-D-Lys (BOC) -OH residue, peptide chain extension was carried out using the standard Boc / Bzl strategy protocol (Protocol 1). After removal of the BOC protection from the s-amino group of D-lysine, a nuclear localization sequence was synthesized. In this case, a 5% solution of DIEA in DMF was used at the neutralization stage, and BOC-Pero-OH was used to attach the N-terminal amino acid residue. Then, the Fmoc protection was removed from the α-amino group of D-lysine and the peptide chain was continued to grow using the Fmoc / Bu ^t- strategy (Protocol 2).

Cleavage of the synthesized peptides from the polymer with simultaneous release was carried out using TFMSA (Protocol 3). The released peptides were desalted on a 15 × 500 mm column with Sephadex G-15 in 50% acetic acid. Further purification was performed using reverse phase HPLC.

HPLC was performed using a System Gold chromatograph (Beckman, USA) on Vydac C 18 columns; Zorbax ODS C 18; Zorbax 300SB-C18 (4.6 × 150 mm, 5 μm) for analytical chromatography and Vydac C18 (22 × 250 mm); Delta Pak C18 (19 × 300 mm); Discovery C18 (10 × 250 mm, 5 μm) for preparative. Chromatography conditions: UV detection at 230 nm, a gradient of acetonitrile in 0.1% TFA or 0.1% H ₂ PO ₄ at a flow rate of 1 ml / min for analytical and a gradient of acetonitrile in 0.1% TFA at a flow rate of 5 ml / min for preparative chromatography.

The resulting compounds were characterized by analytical HPLC, amino acid analysis and mass spectrometry.

NLS-LH-RH. Mass spectrum, found: m / z: 2117.28 [M + H] ⁺ .

Calculated: M 2117.25.

Nuk-1. Mass spectrum, found: m / z: 2209.40 [M + H] ⁺ . Calculated: M 2209.37.

Protocol 1. Synthesis of peptides using the BOC / Bzl strategy.

When conducting solid-phase peptide synthesis, the following combination of protective groups in the side chains of amino acid residues was used: Ser - Bzl; Tur - Bzl (Cl ₂ ), Bzl (Br); Trp - For; Arg - Mts; Lys - Z (Cl). The BOC group served as a temporary N ^α protection.

The growth of the peptide chain was carried out on a semi-automatic peptide synthesizer or manually according to the following protocol for each cycle:

1) CH ₂ Cl ₂ (1 min); 2) 65% TFA / CH ₂ Cl ₂ (1 and 15 min); 3) CH ₂ Cl ₂ (2x0 min); 4) CH ₂ Cl ₂ (2 × 1 min); 5) DMF (1 min); 6) 5% TEA / DMF (1 and 2 min); 7) DMF (3 × 1 min); 8) condensation reaction (2 h); 9) DMF (2 × 1 min); 10) CH ₂ Cl ₂ (1 min).

Four-fold excesses of activated 1-hydroxybenzotriazole esters of the corresponding BOC amino acids obtained in situ (1 equivalent of BOC amino acids, DIC and HOBt, stirring in DMF at 0 ° С, 30 min) were used for condensation. At the end of the reaction, an acylation test was performed. If necessary, steps 5) to 10) were repeated.

In the case of incomplete passage of the condensation reaction when it is repeated 1-2 times, unreacted groups were acetylated (after washing with CH ₂ Cl _2, 10 equivalents of acetic anhydride, 10 equivalents of 10% TEA / CH ₂ Cl ₂ were added to the peptidyl polymer and stirred for 10 min).

Protocol 2. Synthesis of peptides using the Fmoc / Bu ^t strategy.

When conducting peptide synthesis, the following combination of protective groups in the side chains of amino acid residues was used: Ser and Tyr - Bu ^t ; Lys - BOC; His is Trt; Trp - VOS. An Fmoc group served as a temporary N ^α protection.

The growth of the peptide chain was carried out on a semi-automatic peptide synthesizer or manually according to the following protocol for each cycle: 1) CH ₂ Cl ₂ (1 min); 2) DMF (1 min); 3) 20% piperidine / DMF (2 and 8 min); 4) DMF (3 × 1 min); 5) Isopropyl alcohol (3 × 1 min); 6) DMF (3 × 1 min); 7) condensation reaction (2 h); 8) DMF (2 × 1 min); 9) CH ₂ Cl ₂ (1 min).

Four-fold excesses of activated 1-hydroxybenzotriazole esters of the corresponding Fmoc amino acids obtained in situ (1 equivalent of Fmoc amino acids, DIC and HOBt, stirring in DMF at 0 ° С, 30 min) were used for condensation. At the end of the reaction, an acylation test was carried out according to the procedure described in the previous chapter. If necessary, re-condensation used the following protocol:

a) DMF (1 min); b) 5% DIEA / DMF (1 and 2 min), after which stages 6) -9) were repeated.

In the case of incomplete passage of the condensation reaction when it is repeated 1-2 times, unreacted groups were acetylated (after washing with CH ₂ Cl _2, 10 equivalents of acetic anhydride, 10 equivalents of 10% DIEA / CH ₂ Cl ₂ were added to the peptidyl polymer and stirred for 10 min) .

Protocol 3. Cleavage of the peptides from the polymer carrier by TFMSA.

To 100 mg of the peptidyl polymer, 100 μl of thioanisole and 50 μl of ethanedithiol were added and stirred for 10 minutes, after which 1 ml of TFA was added and mixed for 5-10 minutes. To the resulting suspension, 100 μl TFMSA was added dropwise while cooling in an ice bath and stirring. The reaction mixture was stirred for 2 hours at room temperature, then diluted with anhydrous diethyl ether. The precipitate formed together with the polymer particles was filtered off and washed on the filter with diethyl ether. The filtrate was discarded, after which the precipitate was dissolved in TFA, and the resulting solution was filtered from polymer carrier particles into a flask containing 25 ml of anhydrous diethyl ether. The precipitate was kept in the refrigerator for 10-15 minutes, after which it was filtered off, washed on the filter with diethyl ether and dried. The resulting product was dissolved in 50% acetic acid and separated from the excess salts and scavengers by gel filtration.

As the results of the studies show, the claimed invention according to the first and second variants is highly effective in the "suicide" gene therapy of cultured human hepatoma cells HepG2 and relates to a system of non-viral gene transfer into cells of hormone-sensitive mammalian tumors.

The claimed molecular conjugates based on luliberin receptor agonists can achieve significantly better results compared to conjugates based on luliberin receptor antagonists on their use as a means of delivering DNA to hormone-sensitive tumor cells. At the same time, it is worth noting that in vivo conditions, antagonist-based conjugates may be preferable, since they do not cause activation of luliberin-specific signaling pathways.

Based on the results obtained, it can be concluded that the claimed invention (in two versions) allows efficient and targeted delivery of genes to cells of hormone-sensitive tumors. In addition, the high specificity of the penetration of luliberins into tumor cells suggests the prospect of their use for tumor therapy.

The results of such studies, which are shown in the examples of the claimed invention, are not available in the literature and are unknown to the applicant and the authors on the day the application materials are submitted.

List of references

1. Molas M., Gomez-Valades A. G., Vidal-Alabro A., Miguel-Turu M., Bermudez J., Bartrons R., Perales J. C. Receptor-mediated gene transfer vectors: progress towards genetic pharmaceuticals (2003) Curr. Gene Ther. 3 (5): 468-485.

2. Schally A.V. Luteinizing hormone-releasing hormone analogs: their impact on the control of tumorigenesis (1999) Peptides 20 (10): 1247-1262.

3. US patent 5,378,688.

4. US patent 6,214,969.

5. International application PCT / EP96 / 05029 (international publication number W097 / 19954); US patent 6,184,374 Century

6. Xu Y., Szoka Jr. F. C. Mechanism of DNA release from cationic liposome / DNA complexes used in cell transfection (1996) Biochemistry 35: 5616-5623.

7. Ramsay E., Gumbleton M. Polylysine and polyomithine gene transfer complexes: a study of complex stability and cellular uptake as a basis for their differential in-vitro transfection efficiency (2002) J. Drug Target. 10 (1): 1-9.

8. Ignatovich IA, Dizhe E. B., Pavlotskaya AV, Akifiev BN, Burov SV, Orlov SV, Perevozchikov AP Complexes of plasmid DNA with basic domain 47-57 of the HIV Tat protein are transferred to mammalian cells by endocytosis-mediated pathways (2003). J. Biol. Chem. 278 (24): 42625-42636.

9. Diezhe E.B., Ignatovich I.A., Burov S.V., Akifiev B.N., Efremov A.M., Perevozchikov A.P., Orlov S.V. DNA complexes with cationic peptides: formation conditions and factors affecting the efficiency of penetration into mammalian cells (2006). Biochemistry 71 (12): 1659-1667.

The molecular conjugate consists of a cationic component responsible for electrostatic interaction with plasmid DNA, and a ligand component, which is a synthetic analogue of luliberin. In all cases, a modified nuclear signal of the SV40 virus T-antigen was used as the cationic component. The sequence of the cationic component:

H-Pro-Lys-Lys-Lys-Arg-Lys-Val

The first variant of the molecular conjugate contains the following sequence as a ligand component:

Glu-His-Trp-Ser-Tyr-D-Lys-Leu-Arg-Pro-Gly-NH ₂

The cationic moiety is attached via the ε-amino group of the 6th D-Lys. The sequence of the ligand component is a special case of many peptides described by the following formula:

XR ¹ -His-R ³ -Ser-R ⁵ -D-Lys-Leu-Arg-Pro-R ¹⁰ -NH ₂ , where R ¹ is pGlu; R ² is His or D-Phe (4Cl); R ³ -Trp, D-Trp or D-Pal (3); R ⁵ is Tyr or Arg; R ¹⁰ -Gly or D-Ala; X is a hydrogen atom or a lower alkyl group (C ₂ -C ₅ ).

The second variant of the molecular conjugate contains as the ligand component the following sequence:

D-Lys-Pro-Gly-D-Phe-Pro-Ser-Tyr-D-Lys-Leu-Arg-Pro-Gly-NH ₂ . The cationic moiety is attached via the ε-amino group of the first D-Lys.

Claims (3)

1. The molecular conjugate, which is a synthetic analogue of luliberin of the formula
XR ¹ -His-R ³ -Ser-R ⁵ -D-Lys-Leu-Arg-Pro-R ¹⁰ ,
where R ¹ is pGlu;
R ³ is Trp, D-Trp, Pro or D-Pal (3);
R ⁵ is Tyr or Arg;
R ¹⁰ is Gly-NH ₂ , D-Ala-NH ₂ or NH-CH ₂ -CH ₃ ;
X is a hydrogen atom or a lower alkanoyl group (C ₂ -C ₅ ),
in which, through the ε-amino group of D-Lys at position 6, H-Pro-Lys-Lys-Lys-Arg-Lys-Val- is attached. 2. The molecular conjugate according to claim 1, characterized in that it is used as a means of delivering DNA to cells of hormone-sensitive tumors. 3. A molecular conjugate for delivering DNA to cells of hormone-sensitive tumors containing luliberin receptors, in which the cationic component condensing plasmid DNA is a modified nuclear localization signal of the SV40 T-antigen of the formula H-Pro-Lys-Lys-Lys-Arg -Lys-Val- and is attached via the ε-amino group of the N-terminal D-Lys ligand component, and the ligand component interacting with tumor-specific receptors is a synthetic analog of luliberin (antagonist) of the formula
D-Lys-Pro-Gly-R ² -R ³ -Ser-Tyr-R ⁶ -Leu-Arg-Pro-R ¹⁰ -NH ₂ ,
where R ² is an aromatic D-amino acid;
R ³ is Trp, D-Trp, Pro or D-Pal (3);
R ⁶ is a D-amino acid;
R ¹⁰ - Gly, D-Ala.

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