The Role And Mechanism Of SRD5A1 In Colon Cancer

The incidence and mortality of colon cancer rank third and second among various malignant tumors,respectively.The main clinical methods for treating colon cancer are surgical treatment,radiotherapy,chemotherapy and biological therapy.Chemotherapy has remained the main treatment method for patients with advanced colon cancer in the last decade,such as 5-fluorouracil,capecitabine,and oxaliplatin,with the goal of inhibiting tumor size,growth and metastasis.Long-term use of these therapies can lead to serious toxic side effects,chemical resistance,and severely affect the prognosis of patients.SRD5A1 is a steroid 5a-reductase 1 that can convert testosterone to dihydrotestosterone,and thereby regulating hormone levels and the occurrence and development of tumors.At present,the research on SRD5A1 is mainly focused on benign prostatic hyperplasia and prostate cancer.Secondly,there are some research reports in breast cancer,bladder urothelial carcinoma,hepatocellular tumor,and non-small cell lung cancer,but no reports have been reported in colon cancer.In the early stage,the research team adopts immunohistochemistry assay to analyse SRD5AI expression differences between 100 colon cancer patients and 30 normal human colon tissue samples from Nanjing Traditional Chinese Medicine Hospital and finds that SRD5A1 is highly expressed in colon cancer tissues;Western blot results also shows that SRD5AI is expressed higher in colon cancer cells than normal intestinal epithelial cells.In addition,the analysis of the correlation between SRD5A1 expression level and clinicopathological characteristics displays that colon cancer patients with high expression of SRD5A1 have shorter overall and progression-free survival,greater probability of tumor lymph node metastasis and distant metastasis,and poorer prognosis.From this,it can be concluded that SRD5A1 acted as a proto-oncogene which can promote the occurrence and development of colon cancer.In order to further study the mechanism of SRD5A1 in colon cancer,two colon cancer cells with stable expression of SRD5A1 knockdown are firstly constructed by lentivirus infection.The effects of SRD5A1 knockdown on the cell activity,cell cycle,apoptosis,and senescence of colon cancer cells are detected by MTT assay,flow cytometry,and ?-galactosidase staining.The experiments find that after SRD5A1 knockdown,cell proliferation slows,cell cycle arrests in G2/M phase,apoptosis level increases,and cell senescence process accelerates.In addition,dutasteride,as an inhibitor of SRD5A1,can not only affect SRD5A1 activity and protein expression levels,but also inhibit colon cancer cell proliferation,induce cell cycle arrest,and promote apoptosis and cell senescence.The results of the above biological function experiments can only explain from the surface that SRD5A1 acts as a proto-oncogene in colon cancer cells,but its mechanism of action is still unclear.Transcriptome sequencing technology is a technology that uses high-throughput sequencing technology to sequence or analyze all or part of mRNA,small RNA,and no-coding RNA in cells or tissues.The sequencing results can provide possible signal pathways for genes.Transcriptome sequencing is widely used in various studies.To this end,the research team uses transcriptome sequencing technology to futher research and finds that the mechanism of SRD5A1 in colon cancer is closely related to NF-?B,p53,TNF and other signaling pathways.It has been reported that the NF-?B/VEGF signaling pathway is closely related to tumor metastasis in solid tumors.Correlation analysis of clinical pathological features has shown that SRD5A1 high expression is significantly associated with lymph node metastasis and distant metastasis.Therefore,it can be speculated that SRD5A1 may regulate tumor metastasis through the NF-?B/VEGF signaling pathway.And then to verify this speculation.Western blot results show that when SRD5A1 knockdown or inhibited by dutasteride,the expression of NF-?B p65 and the angiogenesis pathway-related factor VEGF protein are down-regulated.In addition,cell scratch assay shows that colon cancer cell migration slowed down after SRD5A1 knockdown,and dutasteride can also weaken cell migration ability.Summarizing the above results,SRD5A1 can regulate VEGF by regulating NF-?B to affect colon cancer cell migration and tumor metastasis.The results of this research provide a theoretical basis for SRD5A1 as a molecular target for the diagnosis and treatment of colon cancer,and dutasteride is expected to become a candidate drug for the treatment of colon cancer.