RNA m5C modification upregulates E2F1 expression in a manner dependent on YBX1 phase separation and promotes tumor progression in ovarian cancer

Abstract

5-Methylcytosine (m⁵C) is a common RNA modification that modulates gene expression at the posttranscriptional level, but the crosstalk between m⁵C RNA modification and biomolecule condensation, as well as transcription factor-mediated transcriptional regulation, in ovarian cancer, is poorly understood. In this study, we revealed that the RNA methyltransferase NSUN2 facilitates mRNA m⁵C modification and forms a positive feedback regulatory loop with the transcription factor E2F1 in ovarian cancer. Specifically, NSUN2 promotes m⁵C modification of E2F1 mRNA and increases its stability, and E2F1 binds to the NSUN2 promoter, subsequently reciprocally activating NSUN2 transcription. The RNA binding protein YBX1 functions as the m⁵C reader and is involved in NSUN2-mediated E2F1 regulation. m⁵C modification promotes YBX1 phase separation, which upregulates E2F1 expression. In ovarian cancer, NSUN2 and YBX1 are amplified and upregulated, and higher expression of NSUN2 and YBX1 predicts a worse prognosis for ovarian cancer patients. Moreover, E2F1 transcriptionally regulates the expression of the oncogenes MYBL2 and RAD54L, driving ovarian cancer progression. Thus, our study delineates a NSUN2-E2F1-NSUN2 loop regulated by m⁵C modification in a manner dependent on YBX1 phase separation, and this previously unidentified pathway could be a promising target for ovarian cancer treatment.

m5C modification: a new pathway in ovarian cancer treatment

Ovarian cancer is the most lethal women’s reproductive system cancer globally, largely due to the absence of early detection techniques. Scientists have discovered that a gene named NSUN2, often found in excess in ovarian cancer, is vital for the cancer’s growth. The research, led by P.Y. and T.L., revealed that NSUN2 encourages the expansion and spread of ovarian cancer cells. They also found that NSUN2 controls the activity of another gene, E2F1, through a method called m5C modification (a process that alters gene expression). This method is essential for E2F1’s RNA stability, a significant factor in cancer growth. The study indicates that focusing on NSUN2 and E2F1 could be a potential treatment approach for ovarian cancer. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.