Aberrant KIF26B expression promotes bladder cancer progression through driving NSUN2 nuclear localization.

Abnormal expression of kinesins has been observed in several types of cancer. The present study provided the first evidence that KIF26B could induce RNA m5C modification in bladder cancer (BCa). Detailly, KIF26B interacted with NSUN2 and recruited ubiquitinase STUB1 to promote K63-linked ubiquitination of NSUN2 at K511 site. K63-linked ubiquitination enabled NSUN2 to bind to KPNA1 and translocate into nucleus where it drove RNA m5C modification. Furthermore, KIF26B induced liquid-liquid phase separation (LLPS) of YBX1 and upregulated IL-6 expression through NSUN2/m5C/YBX1 axis. Secreted IL-6 then activated STAT3 signaling to promote transcription of kif26b through direct binding between STAT3 and kif26b promoter. IL-6 also recruited DLAT to acetylate NSUN2 at K229 site and increased association affinity between NSUN2 and KIF26B. Together, these established a KIF26B/NSUN2/m5C/IL-6 positive feedback loop, suggesting that targeting KIF26B may be a promising therapeutic strategy for BCa.