Mechanism Of USP46 Reducing The Chemosensitivity Of Colon Cancer Cells To Oxaliplatin Through PI3K/AKT/mTOR Signaling

Background:Oxaliplatin resistance is a major challenge in the treatment of advanced colon cancer;both enhancement of anti-apoptotic cells and inhibition of drug accumulation in cancer cells contribute to the development of oxaliplatin resistance.Therefore,exploring ways to improve the sensitivity of colon cancer to oxaliplatin chemotherapy and finding new therapeutic targets is of great significance for the development of effective colon cancer treatments and biomarkers.The ubiquitin-specific protease USP46 is an important member of the ubiquitin-specific protease family,the largest subfamily of deubiquitinases,whose expression is dysregulated in many types of cancer.In recent years,studies have found that the expression of USP46 is associated with cisplatin chemotherapy resistance.However,the biological functions and underlying mechanisms of USP46 in the progression of resistance to oxaliplatin chemotherapy in colon cancer have not been elucidated.Objective:The research plan first proves the expression of USP46 in colon cancer and its correlation with patient prognosis,and then verifies that inhibiting USP46 will affect the biological function of colon cancer and the sensitivity to oxaliplatin chemotherapy through in vitro and in vivo experiments.Finally,the biological mechanism of USP46 in the sensitivity of colon cancer cells to oxaliplatin chemotherapy was preliminarily discussed.The results of this study will demonstrate that USP46 may be a promising diagnostic and prognostic marker for oxaliplatin-based chemotherapy.Methods:Firstly,the UALCAN online tool was used to analyze the differential expression of USP46 gene in colon cancer and normal tissues.Immunohistoche-mistry,qRT-PCR and Western Blot were used to verify the expression levels of USP46 mRNA and protein in colon cancer and paired paracancerous tissues.The correlation between USP46 protein expression and clinicopathological features and its impact on prognosis were analyzed.Then,through the CCK-8 activity test,EdU proliferation test,wound healing test and flow cell apoptosis test,the inhibition of USP46 was used to analyze the biological function of colon cancer cells and the sensitivity to oxaliplatin chemotherapy.Sexual effects were further demonstrated by subcutaneous tumor-bearing experiments in nude mice.Finally,TCGA data can be used for GSEA enrichment analysis,CCK-8 cell viability and Western Blot experiments to explore the mechanism of USP46 affecting colon cancer oxaliplatin chemotherapy sensitivity.Results:The results analyzed by UALCAN online database showed that the expression level of USP46 gene was significantly increased in colon cancer compared with the paired paracancerous tissues.The results of immunohistochemical studies showed that USP46 was highly expressed in colon cancer tissues.The results of qRT-RCR and Western Blot also showed that USP46 m RNA and protein were highly expressed in colon cancer,and patients with high expression were associated with poor prognosis.In addition,in vitro experiments have shown that knocking down the expression of USP46 will promote the sensitivity of colon cancer cells to oxaliplatin treatment,inhibit the proliferation and migration of colon cancer cells,and promote cell apoptosis.In vivo experiments also showed that stably knocking down the expression level of USP46 can inhibit tumor growth and promote the efficacy of oxaliplatin.Subsequently,the TCGA database GSEA enrichment analysis suggested that the USP46 gene was positively correlated with the PI3K/AKT/mTOR pathway in colon cancer.Further Western Blot results showed that knocking down the expression of USP46 would lead to a decrease in the expression of p-PI3K,p-AKT and p-mTOR proteins.Finally,reversion experiments showed that reducing USP46 expression promoted oxaliplatin chemosensitivity in colon cancer cells,but this process was blocked by the addition of a PI3K activator(740Y-P).Conclusion:USP46 is highly expressed in colon cancer and is associated with poor prognosis of patients.Knockdown of USP46 expression will promote colon cancer cell sensitivity to oxaliplatin treatment,inhibit colon cancer cell proliferation and migration,and promote cell apoptosis.USP46 can mediate chemosensitivity to oxaliplatin in colon cancer by regulating PI3K/AKT/mTOR pathway.