| Objective: Gastric cancer is the most common malignant tumor of the digestive system,which seriously threatens human health.Apoptosis is closely related to the occurrence and development of tumors.In tumor cells,the apoptosis of cells is obviously inhibited,which results in the enhancing of proliferation and invasion of tumor cells.Apoptosis inhibitory proteins(IAPs)play an important role in anti-apoptosis of tumor cells.Overexpression of IAPs can lead to dysregulation of apoptosis and tumor development.Survivin and XIAP are important members of the apoptosis-inhibitory protein(IAP)family.They exert strong anti-apoptotic effects through the binding to caspase by their unique BIR domain.Survivin and XIAP are related to each other and are considered as important molecules involved in anti-apoptotic processes.Their high expression in gastric cancer may lead to poor prognosis,and they have become new targets for the treatment of gastric cancer.At present,some drugs targeting survivin have entered clinical trials.YM155 is the first small molecule inhibitor targeting the expression of survivin.YM155 has good tolerability but the results are inconsistent in clinical trials performed on various solid tumors.The same results are also found in the clinical trials of AEG 35156,which is the XIAP’s second-generation antisense oligonucleotide.We suspect that the reason for inconsistent efficacy may be the failure to screen for the dominant population.It is also important to develop new drugs.Currently,there is no online data analysis research on relationship between the clinical pathological parameters and survivin/XIAP.Therefore,further data analysis is still needed to screen for sensitive populations.Drugs targeting the site where Survivin and XIAP bind to each other,may have better therapeutic effects than current survivin and XIAP targeted drugs.Peptide drugs are easy to penetrate into tissues,and have relatively low toxicity.Therefore,we designed and synthesized the polypeptide Supe,which targets the binding site of survivin and XIAP,and we intend to use gastric cancer cells to explore its anti-tumor effect and mechanism.The aim of this study is to analyze the relationship between XIAP/survivin and clinicopathological parameters,prognosis in patients with gastric cancer using online data.Besides,design and develop the peptide Supe,and investigate the mechanism of the Supe’s killing effect.Methods: 1.Gene expression profiles of GSE15459 were downloaded from GEO database of NCBI.The relationship between the expressions of survivin/XIAP and clinicopathological features were analyzed by chi-square test.2.The relationship between the above gene’s expression and prognosis(OS)was analyzed by Kaplan-Meier.3.MTT was used to detect the cytotoxicity of TAT-Supe on gastric cancer cells;4.The changes of apoptosis-related proteins such as Bax,Bcl-2 and Parp were detected by Western Blot.Results: The expression levels of survivin and XIAP were different in Lauren types and molecular types.There was no significant difference in gender and pathological staging.The high expression of survivin occurred in Lauren intestine and mixed type patients(p = 0.007),Besides,survivin in patients with molecular typing of metabolic,proliferative and unstable type were mostly overexpression,while in aggressive patients,the expression of survivin was mostly low(p<0.0001).The high expression of XIAP Occurred in the Lauren intestinal and Lauren mixed type patients,(P = 0.041),high expression of XIAP occurred in patients with molecular typing of proliferative and unstable type(p=0.002).The high expression of survivin and XIAP shows poor prognosis on OS with p values of 0.091 and 0.10,respectively;patients with both low expression had a better prognosis than those with high survivin and / or XIAP expression(P = 0.044).Peptide Supe have a strong killing effect in gastric cancer cells at a concentration of 20μM,but almost no effect on normal fibroblasts cells.The expression of Bax protein increased,the expression of Bcl-2 protein decreased significantly,when treated with Supe.PARP protein cleavage increased,but after adding Z-VAD,PARP cleavage zone disappear.Conclusions: Survivin and XIAP tended to be highly expressed in Lauren intestine patients,and the high expression of survivin and XIAP showed a trend of poor prognosis,the difference was not statistically significant,but the both low expression group shows good prognosis.The self-designed survivin-targeting antitumor peptide Supe has obvious killing effect on tumor cells and can induce tumor cell apoptosis. |
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