MTHFD2 Regulates the AKT/MYC Signaling Pathway in Bladder Cancer and Promotes Proliferation, Viability and Migration in Vitro

Abstract

Background: Numerous studies have reported that MTHFD2 is overexpressed in several human cancers and functions as a valuable prognostic factor. However, little is known about its role in bladder cancer. Methods: We carried out an in silicon analysis of MTHFD2 expression status in bladder cancer tissues and the impact of MTHFD2 on the overall survival of patients. Flag-MTHFD2 plasmid and MTHFD2-knockdown vector were constructed to investigate the function of MTHFD2. The role of MTHFD2 in MTHFD2-overexpressing or MTHFD2-deficient EJ cells was examined using CCK8, colony formation assays, soft agar assays and Transwell migration assays. A luciferase reporter assay was employed to test the impact of MTHFD2 expression on the transcriptional activity of AKT and MYC. The expression of CDK4 and CCND4 in MTHFD2-deficient EJ cells was detected by Western blot. To certify the AKT role in MTHFD2-modulated EJ cell behaviors, a rescue assay were carried out by re-overexpression MYC in MTHFD2-defienct EJ cells.Results: By analyzing the GEPIA database, we found that the expression of MTHFD2 is increased in bladder cancer tissues. Patients with high MTHFD2 displayed poorer survival than patients with low MTHFD2. A series of in vitro functional assays revealed that ectopic expression of MTHFD2 enhanced cell proliferative and migratory activity while MTHFD2 deficiency had the opposite impact on the tumorigenic potential of EJ cells. Mechanistically, we found that overexpressing of MTHFD2 increased AKT and MYC transcriptional activity. Two critical downstream effectors,CDK4 and CCND2 was attenuated in MTHFD2-deficienct cells. Overexpression of MYC rescured the inhibitory effects of MTHFD2 deficiency in the CCND2 and CDK2 expression.Conclusion: Overall, we first uncovered that MTHFD2 could play a protumor role in bladder cancer by activating the AKT/MYC signaling pathway, which may highlight its prognostic potential in bladder cancer and support the rationale for MTHFD2-targeted drug intervention.