Waterpipe smoking as deregulator of RNA m6A modification and promotor of epithelial-mesenchymal transition to cause oral cancer.

e18059 Background: Oral squamous cell carcinoma (OSCC) is a significant health challenge, particularly in the Indian subcontinent, where it ranks as the second leading cancer. Smoking and associated genetic alteration cause OSCC, due to carcinogenic compounds present in tobacco smoke. However, its role in altering N6-methyladenosine is unclear. This study investigates the expression of the m6A master regulator, METTL3, and its influence on cellular proliferation and epithelial-mesenchymal transition (EMT) through waterpipe smoke condensate (WPSC). Methods: This study used various samples, the initial in vitro models utilized OSCC cell lines (SCC25 and CAL27) to examine the effects of WPSC. The preliminary proliferative activity assessed includes cell growth and survival using CCK-8 and MTT assays, clonogenic assays, and cell migration assays. The expression level of RNA m6A regulatory enzyme METTL3 and epithelial-mesenchymal transition (EMT) markers were analyzed using Western blotting and real-time quantitative PCR. The METTL3 expression was further validated in patient sample data from the cancer genome atlas (TCGA) and cBioportal databases. The METTL3 network was identified through bioinformatics software, and functional enrichment analyses were performed. GraphPad Prism software was used for statistical analysis, and p < 0.05 was considered statistically significant. Results: We found that enhanced cell proliferation, increased clonogenic ability, cell migration, and elevated METTL3 expression in WPSC-induced OSCC cell lines compared to controls (p < 0.05). In addition, WPSC treatment resulted in the downregulation of the epithelial marker E-cadherin and the upregulation of mesenchymal markers, N-cadherin, Snail1, and Vimentin (p < 0.05). Furthermore, the TCGA dataset confirmed that METTL3 is altered in smoking- the cancer group (p < 0.05) and bioinformatics analysis suggest METTL3 plays a critical role in methylation and carcinogenesis. Conclusions: WPSC stimulates OSCC progression by activating METTL3 and inducing EMT. These insights emphasize the need to target the METTL3 pathway in treating smoking-associated OSCC.