CN106349376A - Human SFRP1 (secreted frizzled-related protein 1) variant and application thereof - Google Patents

Abstract

The invention discloses a human SFRP1 (secreted frizzled-related protein 1) protein variant and application thereof to preparation of medicine for inhibiting the tumor growth. The human SFRP1 variant provided by the invention is used for overexpression in cancer cells, or in-vitro supply of the SFRP1 protein variant is performed, so that the cancer cell proliferation can be controlled; the cancer cells can be killed.

Description

People's sfrp1 variant and its application

Technical field

The invention belongs to biological technical field, specifically, the present invention relates to tumor suppressor protein variant.

Background technology

Sfrp, secreting type frz associated protein (secreted frizzled-related proteins), containing a richness Domain (cysteine rich domain, crd) containing cysteine, but lack seven membrane-spanning domains, it may be with curling egg (frizzled, frz) competition binding wnt albumen in vain, thus suppress the overexpression of wnt albumen.Wnt is a class secreting type sugar egg In vain, human normal cell has been bred with adjustment facilitation.Recent experimental finds, the gene sfrp of suppression this protein effect When occurring abnormal, can exception therewith so that cancerous cell is constantly bred in the function of wnt protein, and leads to colorectal cancer.When After normal sfrp gene injection cancerous cell, cancer cell multiplication will be controlled and kill cancerous cell.Research shows, 90% big Patients with bowel cancer is relevant with sfrp gene unconventionality.

In the prior art, in order to improve the activity of albumen, for albumen avtive spot carry out specific mutation and Replace, thus finding the higher variant of activity is conventional way.In order to improve the biological activity of this albumen, applicant further By substantial amounts of experiment, carry out point mutation for site specific in sfrp1 aminoacid sequence, thus obtain comparing sfrp1 Albumen has the variant of higher inhibitory activity in itself.

Detailed Description Of The Invention

The present invention relates to the detached variant of Parent Protease, it corresponds to the ripe many of seq id no:1 at least one The position 34y of peptide, 39f, 42d, 50r, 58c, 63a, 89e, 100l, 122l, 137r, 151w, 174a, 198i, 220n, 242d, The position of 271m, 286k or 293e comprises to modify.Specifically, the variant of the present invention has the inhibitory activity of improvement.

Preferably, be applied to the method for the present invention, present improvement inhibitory activity protein variant be following arbitrary modification: 34y/a、39f/d、42d/r、50r/s、58c/g、63a/h、89e/a、100l/d、122l/r、137r/s、151w/g、174a/r、 198i/a, 220n/s, 242d/g, 271m/d, 286k/r or 293e/l.

The invention still further relates to the method producing the protein variant of the present invention, cultivate host cell including (a)；(b) reclaim Described protein variant.

In the production method of the present invention, it is being suitable for producing the nutrition training of described polypeptide using method well known in the art Cultured cells in foster base.For example, it is possible to by suitable culture medium and under conditions of permission expression and/or the described polypeptide of separation Small-scale in the shake-flask culture carrying out, and laboratory or industrial fermentation tank or large scale fermentation (include continuous, in batches, feed supplement In batches or solid fermentation) carry out cultured cells.Cultivated in suitable Nutrient medium using methods known in the art, institute State Nutrient medium and comprise carbon source and nitrogen source and inorganic salt.Suitable culture medium can obtain from commercial supplier or can basis Disclosed composition prepares (for example, in the catalogue of American type culture collection).If polypeptide is secreted into nutrition culture In base, this polypeptide directly can reclaim from described culture medium.If polypeptide is not secreted, it can be from cell lysate (lysate) reclaim.

Gained polypeptide can be reclaimed using methods known in the art.For example, polypeptide can be by conventional method from nutrition Reclaim in culture medium, described conventional method is including but not limited to centrifuged, filters, extracting, being spray-dried, evaporating or precipitation.

The polypeptide of the present invention can be by multiple methods known in the art purification, and methods described includes but is not limited to chromatograph (for example, ion exchange, affine, hydrophobic, chromatofocusing and size exclusion), electrophoresis method (for example, preparative (preparative) isoelectrofocusing), differential solubility (for example, ammonium sulfate precipitation), sds-page or extract (see, e.g., Protein purification, j.-c.janson and lars ryden compiles, vch publishers, new york, and 1989).

The polypeptide of the present invention is used for preparing corresponding medicine, goes for treating cancer.

Specific embodiment

1. the acquisition of sfrp1 gene

Pcr expands orf area totally 314 aminoacid of sfrp1, and template is the sample containing human genome.Two ends introduce Restriction enzyme site bamhi and ecori, is connected with the pet carrier of same enzymic digestion after enzyme action, chooses Dan Ke after conversion escherichia coli Grand, sequencing.Record its aminoacid sequence as shown in sequence 1.

Primer sequence used is as follows, and the primer of sfrp1 is (do not remove termination codon and do not contain his-myc):

Sfrpl 3.1b (-): f:5 '-cgggatccatgggcatcggg-3 ':

R:5 '-cggaattccgtcacttaaacacggact-3 '.

2. the structure of sfrp1 variant

The introducing of catastrophe point

(1) corresponding mutagenic primer is designed according to corresponding mutational site, using pcr fixed-point mutation method in sfrp1 gene The corresponding amino acid sites of upper wild type are mutated；

(2) above-mentioned pcr product through glue reclaim after purification, carries out enzyme action with restricted enzyme, and through identical enzyme action After plasmid pcdna3.1 fragment connects, convert escherichia coli dh5 α competent cell；

3. 2. identification recombiant plasmid: with enzyme action, pcr method, recombiant plasmid is identified, and the inspection that is sequenced, thus Nucleotide sequence to after mutation.

4. pcdna3.1-sfrp1 variant plasmid construction

The two ends that second step is built the sfrp1 variant gene obtaining introduce restriction enzyme site bamhi and ecori, after enzyme action It is connected with the pcdna3.1 of same enzymic digestion, after identification, by plasmid-transfected cells strain: 7721 hepatoma carcinoma cell, check sfrp1 Become the effect of the suppression liver cancer cell growth of physical ability.Concrete outcome is as follows:

Table 1 sfrp1 variant overexpression cell growth inhibiting situation

By the above results as can be seen that some mutants to the inhibitory activity of liver cancer cell growth with respect to wild type Sfrp1 albumen has increased significantly, and can further apply liver cancer treatment.

Sequence table

<110>Li Luqing

＜ 120 ＞ people's sfrp1 variant and its application

〈160〉1

〈210〉1

〈211〉314

〈212〉prt

＜ 213 ＞ homo sapiens (homo sapiens)

〈400〉1

1 mgigrseggr rgaalgvlla lgaallavgs aseydyvsfq sdigpyqsgr

51 fytkppqcvd ipadlrlchn vgykkmvlpn llehetmaev kqqasswvpl

101 lnknchagtq vflcslfapv cldrpiypcr wlceavrdsc epvmqffgfy

151 wpemlkcdkf pegdvciamt ppnateaskp qgttvcppcd nelkseaiie

201 hlcasefalr mkikevkken gdkkivpkkk kplklgpikk kdlkklvlyl

251 kngadcpchq ldnlshhfli mgrkvksqyl ltaihkwdkk nkefknfmkk

301 mknhecptfq svfk

Claims (4)

1. a kind of people's sfrp1 albumen, its aminoacid sequence is shown in seq id no:1.

2. a kind of people's sfrp1 protein variant is it is characterised in that on the basis of the aminoacid shown in seq id no:1, 174a/r is replaced accordingly.

3. purposes in preparation suppression tumour medicine for the protein variant as claimed in claim 2.

4. a kind of anti-tumor medicinal preparation, it contains protein described in claim 2 and pharmaceutically suitable carrier.