METTL5-mediated m6A modification of UBE3C promotes osteosarcoma progression by suppressing ferroptosis via inducing AHNAK ubiquitination.

Ferroptosis, marked by iron-dependent lipid peroxidation, emerges as a promising approach for osteosarcoma (OS) intervention due to its tumor susceptibility. Ubiquitination is a key post-translational modification involved in regulating cell ferroptosis and is closely linked to cancer development. Ubiquitin protein ligase E3C (UBE3C), an E3 ubiquitin ligase plays a carcinogenic role in several cancers. However, the roles and molecular mechanisms of UBE3C in OS cell ferroptosis remain unclear. UBE3C level was enhanced in OS tissues and cells, and UBE3C depletion impeded OS cell proliferation, migration, and invasion and accelerated ferroptosis. Moreover, Fer-1 administration counteracted the inhibitory impact of UBE3C silencing on the malignant behavior of U2OS and 143B cells. Mechanistically, UBE3C promoted the ubiquitination and degradation of AHNAK in U2OS and 143B cells. AHNAK counteracted the effect of UBE3C on promoting cell proliferation, migration, and invasion and inhibiting cell ferroptosis. Further, METTL5-mediated m6A modification enhanced UBE3C mRNA stability by enabling YTHDF1 to bind and protect the modified mRNA from degradation. METTL5 addition inhibited AHNAK level which was abolished by UBE3C silencing. Our work uncovered a new METTL5-YTHDF1-UBE3C-AHNAK signaling axis regulating ferroptosis and driving OS progression. Targeting this axis offers a promising approach to enhance ferroptosis sensitivity against OS.