Fig. 1

Expression of METTL3 and its clinical significance in SCLC. A Heatmap of the mRNA expression of 12 common m6A regulators in the SCLC chemotherapy-sensitive cell line H69 and the drug-resistant cell line H69AR based on whole-transcriptome sequencing. Cell types are indicated on the top of the heatmap, and m6A regulator-specific gene names are indicated on the right; the left side shows significance. If P < 0.05, the significance is marked as YES, and if P ≥ 0.05, the significance is marked as NO. B-C Forest plot showing the univariate Cox regression analysis of significant differences between m6A regulators and overall survival (OS) in the SCLC clinical cohort GSE60052 from the GEO public database (B) and the SCLC clinical cohort from local hospitals (C). The main part of the forest plot is composed of hazard ratios (HRs) and 95% confidence intervals (CIs), and the P value is also marked in the fig. HR < 1 is a predictor for favourable OS, and HR > 1 is a predictor for poor OS. D Kaplan–Meier analysis was used to compare the effect of high and low METTL3 expression on OS in the SCLC cohort from GSE60052 (left) and from local hospitals (right); P values are marked in the fig. E qRT-PCR analysis of METTL3 mRNA expression in two pairs of chemosensitive and chemoresistant SCLC cells, H69/H69AR and H446/H446DDP. **P < 0.01; ***P < 0.001. F Western blot analysis of METTL3 expression in two pairs of chemosensitive and chemoresistant SCLC cells, H69/H69AR and H446/H446DDP. G Immunofluorescence analysis of METTL3 expression in H69/H69AR and H446/H446DDP cells. Scale bars, 25 μm. Quantification of METTL3 expression detected by immunofluorescence is shown. The data originated from 3 independent experiments. **P < 0.01; ***P < 0.001