Sinomenine attenuates the growth and immune evasion of gastric cancer by regulating the METTL3/MEST-mediated RhoA/ROCK2 signaling pathway.

BACKGROUND

Sinomenine (SIN) exhibits inhibitory effects on different types of tumor cells, containing gastric cancer (GC). However, the anti-cancer molecular mechanism of SIN in GC is still not fully revealed.

METHODS

Cell viability, proliferation, apoptosis, and migration were assessed using MTT, EdU, flow cytometry, and transwell. To understand the role of SIN during the immune escape, GC cells were co-cultured with peripheral blood mononuclear cells (PBMCs) in vitro. Effects of GC cells on apoptosis ratio, proliferation, and cytotoxicity of CD8+ T cells were detected using flow cytometry and LDH cytotoxicity Kit. Methyltransferase-like 3 (METTL3) and Mesoderm-specific transcript (MEST) expression were measured using RT-qPCR. Western blot detected METTL3, MEST, RHOA, and ROCK2 protein expression. After being predicted using SRAMP and RMbase, the possible interaction between METTL3 and MEST was identified using MeRIP-qPCR and RIP assays. Role of SIN on GC cell growth in vivo was assessed by a xenograft model.

RESULTS

SIN blocked GC cell growth and immune escape. METTL3 and MEST content was reduced in SIN-treated GC cells. METTL3 upregulation relieved anti-tumor effects of SIN on GC cells. In mechanism, METTL3 enhanced the stability of MEST mRNA via m6A methylation. SIN modulated the RhoA/ROCK2 signaling pathway by the METTL3/MEST axis. SIN suppressed tumor growth in vivo.

CONCLUSION

SIN treatment repressed GC cell development partially by the METTL3/MEST axis, providing a possible therapeutic strategy for GC.