METTL3 regulates the proliferation, metastasis and EMT progression of bladder cancer through P3H4.

Bladder cancer, the most common malignant tumor in the urinary system, exhibits significantly up-regulated expression of P3H4, which is associated with pathological factors. The objective of this study was to elucidate the underlying mechanism of P3H4 in bladder cancer. Initially, we analyzed P3H4 gene expression using the TCGA database and evaluated P3H4 levels in clinical samples and various bladder cell lines. P3H4 was found to be markedly overexpressed in bladder cancer samples. Subsequently, bladder cancer cells were transfected with shRNA targeting P3H4 (sh-P3H4), sh-METTL3, and P3H4 overexpression vectors (P3H4 OE). Viability, migration, and invasion of bladder cancer cells were assessed using CCK-8, wound healing, and transwell assays. Western blot analysis was performed to determine the levels of EMT-associated proteins, while RNA stability assays determined the half-life of P3H4. Knockdown of P3H4 resulted in inhibition of bladder cancer cell proliferation, migration, invasion, and EMT progression. Mechanistically, METTL3 was found to regulate the mRNA stability of P3H4 in bladder cancer. Moreover, overexpression of P3H4 reversed the inhibitory effects of METTL3 knockdown on bladder cancer cell behaviors. Stable cell lines were established by infecting EJ cells with lentiviral vectors containing sh-METTL3 or P3H4 OE. These cells were then implanted into the skin of BALB/c nude mice, and IHC analysis was used to analyze the expression levels of EMT-associated proteins. In vivo studies demonstrated that inhibition of METTL3 suppressed bladder cancer growth and EMT through P3H4. In conclusion, our findings suggest that METTL3 regulates the proliferation, metastasis, and EMT progression of bladder cancer through P3H4, highlighting its potential as a therapeutic target.