Regulation of NSCLC Cell Proliferation By MARCH7 Via the NF-κB and Wnt/β-Catenin Signaling Pathways

Abstract The aim of the study was to explore the role of the E3 ubiquitin ligase MARCH7 in the development of non-small-cell lung cancer (NSCLC) and to explore the underlying molecular mechanism.Western blot and immunohistochemistry results showed that the expression of MARCH7 in NSCLC cancer tissues was higher than that in paracancerous tissues. Tissue microarray staining results and clinicopathological parameters of NSCLC patients revealed that MARCH7 expression was closely related to TNM stage, degree of tumor differentiation and lymph node metastasis of NSCLC patients. Furthermore, univariate and multivariate analyses and survival curve analysis showed that high expression of MARCH7 was associated with poor prognosis.In vitro, siRNA was constructed and transfected into A549 cells to inhibit the expression of MARCH7. The CCK-8 assay indicated that the growth rate of tumor cells in the interference group was reduced. The number of colonies and cells in the interference group decreased in the plate clone formation experiment. Flow cytometry showed that G0/G1 phase cells were predominantly increased after blocking endogenous MARCH7 expression, and G0/G1 phase arrest occurred in A549 cells. The reporter gene activity of the NF-κB signaling pathway and Wnt/β-catenin signaling pathway was reduced, as validated by a double luciferase reporter gene assay. Western blot analysis showed that the expression of NF-κB P50, NF-κB P65 and β-catenin was decreased, while the expression of E-cadherin was elevated.In vivo, MARCH7-overexpressing virus was constructed and transfected into A549 cells and then subcutaneously injected into nude mice. It was demonstrated that the tumor volume was significantly larger in the MARCH7 overexpression group than in the control nude mice during the same period. Elevated expression of PCNA and Ki-67 was observed in the tumor mass of the MARCH7 overexpression group, as measured by immunohistochemical analysis, accompanied by enhanced levels of NF-κB P50, NF-κB P65 and β-catenin, as detected by Western blot. These results provide a new idea for the experimental basis for the treatment of NSCLC in the future.