MYH9 Inhibits Cell Apoptosis Of Non-Small Cell Lung Cancer Cells Through The AKT/c-Myc Pathway

Background and PurposesAs a part of myosin heavy chain,MYH9 has been reported to be overexpressed in multiple cancer and involved in the process of tumor dryness,proliferation,and invasion.It has been shown that MYH9 is associated with cisplatin resistance in non-small cell lung cancer,and that MYH9 recruits USP7,increases c-Myc deubiquitination prompting nuclear translocation,activates epithelial-mesenchymal transition,and increases cisplatin resistance.However,the relationship between MYH9 and apoptosis in non-small cell lung cancer has not been investigated.Therefore,by studying the expression of MYH9 in non-small cell lung cancer and the effect of MYH9 knockout on cell proliferation,apoptosis,and cisplatin sensitivity,this study explored the role of MYH9 in non-small cell lung cancer and provided a new potential target for the diagnosis and treatment of non-small cell lung cancer.Method1.Expression and clinical significance of MYH9 in non-small cell lung cancer(1)To clarify the relationship between MYH9 expression and clinical prognosis of patients based on database analysis;(2)The expression of MYH9 in tumor and paracancer tissues was detected by immunohistochemical staining.(3)The expression of MYH9 in non-small cell lung cancer cell lines and immortalized normal bronchial epithelial cells was detected by Western blot.(4)The relationship between MYH9 and prognosis of patients was analyzed based on immunohistochemical staining score and clinical information of patients.2.The MyH9-knockout NSCLC cell line was constructed using CRISPR/Cas9 technology(1)sgRNA sequences were screened in pre-experiment;(2)Lentivirus was used to construct MYH9 knockout cell line.3.To clarify the effects of MYH9 on cell proliferation,apoptosis and cisplatin chemotherapy sensitivity(1)CCK-8 assay and clonal formation assay were used to detect the effect of MYH9 knockout on cell proliferation.(2)The effect of MYH9 knockout on apoptosis was detected by flow cytometry;(3)The effect of MYH9 knockout on cisplatin sensitivity of tumor cells was detected by CCK-8 assay.(4)The effect of MYH9 knockout on cell proliferation in vivo was examined in subcutaneous transplantation tumor model of nude mice.4.The signaling pathway of MYH9 regulating cell apoptosis was clarified(1)The changes of apoptosis-related proteins were detected by Western blot.(2)Western blot was used to detect the changes of apoptosis-related signaling pathways.(3)Immunohistochemical staining was used to verify the changes of apoptotic proteins and related signaling pathways in subcutaneous grafts of nude mice.Result1.Based on clinical specimens and cell line analysis,MYH9 was up-regulated in cancer tissues(P<0.001);Based on database and clinical sample analysis,patients with high expression of MYH9 had shorter survival(P<0.05).2.MYH9 knockout inhibited cell proliferation in vitro and in vivo(P<0.001)and promote apoptosis(P<0.05),increased the chemical sensitivity of tumor cells to cisplatin.3.Molecular mechanisms suggest that MYH9 knockout inactivates the AKT/c-Myc axis(P<0.05)and inhibited the expression of Bcl-xl(P<0.05),promote the expression of BID and BAX(P<0.05),activate caspase3 and caspase9(P<0.05).ConclusionMYH9 promotes progression of non-small cell lung cancer by regulating apoptosis through the AKT/c-Myc axis.