The Comprehensive Analysis of N6-Methyadenosine Writer METTL3 and METTL14 in Gastric Cancer

Prognostic significance of N6-methyladenosine-modified related chemotransferase METTL3 in gastric carcinoma: Evidence from meta-analysis

BACKGROUND

N6-methyladenosine (m6A) methylation is known as the research hotspot for tumor epimodification, and its associated methyltransferase-like3 (METTL3) is significantly differentially expressed in gastric carcinoma, but its clinical value has not been summarized. This meta-analysis aimed to evaluate the prognostic significance of METTL3 in gastric carcinoma.

MATERIAL AND METHODS

Databases, including PubMed, EMBASE (Ovid platform), Science Direct, Scopus, MEDLINE, Google Scholar, Web of Science, and Cochrane Library, were used to identify relevant eligible studies. The endpoints included overall survival, progression-free survival, recurrence-free survival, post-progression survival, and disease-free survival. Hazard ratios (HR) with 95% confidence intervals (CI) were used to correlate METTL3 expression with prognosis. Subgroup and sensitivity analyses were performed.

RESULTS

Seven eligible studies involving 3034 gastric carcinoma patients were recruited for this meta-analysis. The analysis showed that high METTL3 expression was associated with significantly poorer overall survival (HR  =  2.37, 95% CI 1.66-3.39, P < 0.01) and unfavorable disease-free survival (HR  =  2.58, 95% CI 1.97-3.38, P  < 0.01), as did unfavorable progression-free survival (HR  =  1.48, 95% CI 1.19-1.84, P  < 0.01)/recurrence-free survival (HR  =  2.62, 95% CI 1.93-5.62, P  < 0.01)/post-progression survival (HR  =  1.53, 95% CI 1.22-1.91, P  < 0.01). Subgroup analysis found that high METTL3 expression was associated with worse overall survival in patients with Chinese (HR  =  2.21, 95% CI 1.48-3.29, P  < 0.01), in studies with sample source from formalin-fixed, paraffin-embedded tissues (HR  =  2.66, 95% CI 1.79-3.94, P  < 0.01), and the reported directly from articles group (HR  =  2.42, 95% CI 1.66-3.53, P  < 0.01). The subgroup analysis that was performed based on sample size, detected method, and follow-up showed the same results.

CONCLUSIONS

High expression of METTL3 predicts poor prognosis in gastric carcinoma, indicating promise for METTL3 as a prognostic biomarker.Systematic review registration: https://www.crd.york.ac.uk/prospero, ID = CRD42023408519.

METTL3-mediated m6A modification of lncRNA SNHG3 accelerates gastric cancer progression by modulating miR-186-5p/cyclinD2 axis

OBJECTIVES

METTL3 as an m6A methyltransferase acts in diverse malignancies including gastric cancer (GC). We aimed to reveal the underlying mechanisms by which METTL3 contributes to gastric carcinogenesis.

METHODS

The association of METTL3 and SNHG3 with GC was analyzed by qRT-PCR, Western blot, and TCGA cohort. The functional experiments were implemented to uncover the role of METTL3 in GC. m6A dot blot and MeRIP were used to determine METTL3-mediated m6A modification of lncRNA SNHG3. The effect of METTL3 on SNHG3-mediated miR-186-5p/cyclinD2 axis was evaluated by luciferase gene report, RT-qPCR, and Western blot assays.

RESULTS

We found that METTL3 was remarkably elevated in GC tissues and correlated with poor survival in patients with GC. Silencing of METTL3 impaired GC cell growth and invasion, whereas restored METTL3 expression promoted these effects. Mechanistically, reduced expression of METTL3 decreased SNHG3 m6A level and caused a decrease in SNHG3 expression, which could further act as a sponge of miR-186-5p to upregulate cyclinD2. Overexpression of SNHG3 attenuated METTL3 knockdown-induced anti-proliferating and miR-186-5p upregulation and cyclinD2 downregulation.

CONCLUSION

We find that METTL3-mediated m6A modification of lncRNA SNHG3 accelerates GC progression by modulating miR-186-5p/cyclinD2 axis.