Ubiquitin Specific Peptidase 48 Deubiquitinates METTL3 to Modulate Ferroptosis in Gastric Cancer Cells

Ferroptosis, an iron-dependent cell death, is a promising target in gastric cancer. METTL3, an m6A RNA methyltransferase, drives tumor progression, but its role in ferroptosis regulation and the involved deubiquitinating enzymes (DUBs) remain unclear. Here, we demonstrated that METTL3 expression heterogeneity in different gastric cancer cells, identified functional role of METTL3 in modulating ferroptosis sensitivity. In MKN-7 and GCIY cells, forced METTL3 overexpression conferred resistance to ferroptotic stress by driven GPX4 and FTH1 expression, and inhibiting oxidative stress accumulation. Conversely, METTL3 depletion sensitized cells to ferroptosis, and promoted ferroptotic oxidative damage. Through a comprehensive screening of deubiquitinases, we identified ubiquitin specific peptidase 48 (USP48) as a critical stabilizer of METTL3 protein. Functional assays revealed that USP48 mimics METTL3's protective role against ferroptosis, while METTL3 overexpression rescued the ferroptosis sensitivity caused by USP48 knockdown. Mechanistically, this USP48-METTL3 axis regulated key ferroptosis markers including GPX4, FTH1, lipid peroxidation, iron accumulation, and reactive oxygen species (ROS) levels. Our findings reveal a novel regulatory pathway by which USP48 controls ferroptosis sensibility in gastric cancer cell via METTL3 stabilization. This crosstalk between the ubiquitin-proteasome system and m6A transferases highlights the USP48-METTL3 axis as a promising target to sensitize gastric cancer cells to ferroptosis-inducing therapy.