Synthetic peptide sp2 and application thereof

Abstract

A synthetic peptide sp2 has the amino acid sequence shown in SEQ ID No. 1. sp2 has obvious anti-tumor growth activity on xenograft tumours such as subcutaneous human pancreatic cancer, human cervical cancer, and human ovarian cancer in nude mice, with a dose-effect and time-effect relation; and has the effect of delaying metastasis and prolonging the survival time of nude mouse having in situ transplantation of human pancreatic cancer and lung adenocarcinoma. After the animals were given intravenous injection of sp2 at a dose of 2000 mg/kgBW, no toxicity reaction and death were observed. The applications of sp2 also include: (1) preventing and/or treating of tumor; (2) inhibiting proliferation and/or growth and/or invasion of tumor cells; (3) enhancing the anti-tumor immune response; (4) inducing tumor cell differentiation; (5) preparing anti-tumor drugs; (6) inhibiting tumor telomerase activity; and (7) regulating the tumor cell cycle.

Description

INCORPORATION OF SEQUENCE LISTING[0001]This application contains a sequence listing submitted in Computer Readable Form (CRF). The CFR file containing the sequence listing entitled “PA128-0088_ST25.txt”, which was created on Nov. 17, 2020, and is 512 bytes in size. The information in the sequence listing is incorporated herein by reference in its entirety.TECHNICAL FIELD[0002]The present disclosure belongs to the technical field of biomedicine, and relates to a synthetic peptide sp2 and an application thereof, especially an application in preparing new non-cytotoxic anti-tumor drugs.BACKGROUND[0003]Cancer patients urgently need safe and effective anti-tumor drugs. Pancreatic cancer is extremely malignant and has an insidious onset. At first diagnosis, metastasis to peripancreatic organs or lymph nodes, liver metastasis, and distant metastasis have occurred. It is called the king of cancer. The most widely used in traditional chemotherapy for pancreatic cancer are cytotoxic anti-tumo...

AI Technical Summary

Benefits of technology

[0014]The present disclosure has found in the in vitro screening test that sp2 has obvious proliferation inhibitory activity on human pancreatic cancer BxPC-3 (FIG. 2).

[0015]The in vivo efficacy test of sp2 uses nude mouse subcutaneous and nude mouse human carcinoma in situ xenograft tumor models. The evaluation indexes of the anti-tumor activity effectiveness of sp2 on human cancer xenograft tumor model subcutaneously in nude mice include two in vivo efficacy evaluation indexes: relative tumor proliferation rate T / C (%) and tumor growth inhibition rate (%). It has obvious efficacy on human cervical cancer SiHa, human pancreatic cancer in situ BxPC-3, human ovarian cancer A2780, human osteosarcoma MG-63 and human poorly differentiated pregastric cancer BGC-823 subcutaneously in nude mice, and has a significant dose-effect and time-effect relationship (FIGS. 3a-3e).

[0016]Tumor metastasis and recurrence are important reasons for the death of tumor patients. The sp2 of the present disclosure can significantly delay the occurrence of tumor metastasis of the xenograft tumors of nude mouse human lung adenocarcinoma in situ A549 and human pancreatic cancer in situ BxPC-3, and prolong the median survival time of tumor-bearing nude mice (FIGS. 4a and 4b). In vivo imaging shows that there is no difference between the fluorescence intensity of the sp2 high-dose group and the positive control taxol group, that is, there is no difference in efficacy of the two groups (FIG. 5). The safety of sp2 lies in that after the upper and lower methods of acute toxicity test and the maximum dose method are used to inject sp2 at a dose of 2000 mg / kgBW into the tail vein of ICR and Kunming mice respectively, no damage is found within a specified time (continuous Observation for 14 days), including no obvious behavioral abnormalities, no weight loss, and no death. After the experiment, no tissue or organ abnormality is found after general dissection. It is proved that the maximum non-toxic dose of intravenous administration is 2000 mg / kgBW (Examples 12, 13 and FIG. 12).

[0017]The immortal division and proliferation of tumor cells are related to the continuous synthesis of telomere DNA fragment TTAGGG by telomerase through its own RNA template. sp2 can significantly inhibit tumor telomerase activity (FIG. 6);

[0018]It is found in the application that sp2 has an obvious inducing differentiation effect on malignant tumor cell HL-60 and its inducing differentiation process is (FIGS. 7a-7c): after sp2 is incubated with acute promyelocytic leukemia cell HL-60 for 5 days, the HL-60 cell cycle is detected by flow cytometry. Compared with the control group, after sp2 treatment, the expression of cells in the HL-60G0 / G1 phase is increased significantly, the expression of cells in the G2 / M phase is reduced, and the expression of cells in the S phase is reduced, showing a G1 phase arrest (FIG. 7a); At the same time, after sp2 is incubated with acute promyelocytic leukemia cell HL-60 for 5 days, mature cells are increased significantly (FIG. 7b) in the tumor cell HL-60 morphology, and the NBT reduction ability is significantly enhanced (FIG. 7c) in the function, indicating that cell proliferation to differentiation is a process of cell cycle arrest and activation to induce differentiation (morphological and functional changes), and sp2 has a significant role in promoting differentiation of tumor cells.

[0019]The present disclosure has found that when sp2 is administered in vivo at 16 mg / kg / day for 4 consecutive weeks, subcutaneous human xenograft tumors in nude mice (the tumor cells of osteosarcoma, ovarian cancer and human poorly differentiated pregastric cancer tested) show obvious apoptosis (FIG. 8).

Problems solved by technology

Cytotoxic anti-tumor drugs have a strong killing or inhibitory effect on tumor cells, but for the treatment of pancreatic cancer, single-agent chemotherapy has poor efficacy and short survival, so combined chemotherapy is often used, such as FAM (5-FU, ADM, MMC), SMF (STZ, MIVIC, 5-FU) regimens, etc.

While cytotoxic anti-tumor drugs kill or inhibit tumor cells, they also have an impact on normal cells of the body, especially cells with vigorous metabolism, and usually lead to adverse reactions in patients at effective doses.

However, toxic side effects such as allergic reactions, bone marrow suppression, neurotoxicity, and cardiovascular toxicity do more harm to cancer patients.

However, the research on the application of sp2 in new anti-tumor drugs is blank.

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