N⁶-Methyladenosine (m⁶A) is the most abundant RNA modification in mammal mRNAs and increasing evidence suggests the key roles of m⁶A in human tumorigenesis. However, whether m⁶A, especially its ‘reader’ YTHDF1, targets a gene involving in protein translation and thus affects overall protein production in cancer cells is largely unexplored. Here, using multi-omics analysis for ovarian cancer, we identified a novel mechanism involving EIF3C, a subunit of the protein translation initiation factor EIF3, as the direct target of the YTHDF1. YTHDF1 augments the translation of EIF3C in an m⁶A-dependent manner by binding to m⁶A-modified EIF3C mRNA and concomitantly promotes the overall translational output, thereby facilitating tumorigenesis and metastasis of ovarian cancer. YTHDF1 is frequently amplified in ovarian cancer and up-regulation of YTHDF1 is associated with the adverse prognosis of ovarian cancer patients. Furthermore, the protein but not the RNA abundance of EIF3C is increased in ovarian cancer and positively correlates with the protein expression of YTHDF1 in ovarian cancer patients, suggesting modification of EIF3C mRNA is more relevant to its role in cancer. Collectively, we identify the novel YTHDF1-EIF3C axis critical for ovarian cancer progression which can serve as a target to develop therapeutics for cancer treatment.

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.

Cervical cancer (CC) is one of the most common gynecological malignancies with poor prognosis for advanced CC patients. LRRC8A is a volume-regulated anion channel protein involved in cellular homeostasis, but its role in CC remains largely unknown. In this study, we found that LRRC8A is elevated in CC and associated with poor prognosis. LRRC8A maintains cell survivals under the hypotonic condition, and promotes tumorigenesis through apoptosis suppression in vitro and in vivo. Notably, LRRC8A is upregulated by NSUN2-mediated m⁵C modification. m⁵C modified-LRRC8A mRNA is bound by the RNA binding protein YBX1 followed by the increased RNA stability. Moreover, loss of NSUN2 suppresses the proliferation and metastasis of CC cells, and NSUN2 expression is positively correlated with LRRC8A expression in CC. Altogether, our study demonstrates that the NSUN2-m⁵C-LRRC8A axis is crucial and would be a potential therapeutic target for CC.

N6-methyladenosine (m⁶A) is the most common post-transcriptional modification of RNA in eukaryotes, which has been demonstrated to play important roles in various cancers. YTHDF1 acts as a crucial m⁶A “reader” and regulates the fate of m⁶A modified mRNA. However, its role in cervical cancer remains unknown. In this study, we showed that YTHDF1 was highly expressed in cervical cancer, and was closely associated with the poor prognosis of cervical cancer patients. YTHDF1 knockdown suppressed the growth, migration and invasion, and induced apoptosis of cervical cancer cells. Moreover, YTHDF1 knockdown inhibited tumorigenesis of cervical cancer cells in vivo. Through combined on-line data analysis of RIP-seq, meRIP-seq and Ribo-seq upon YTHDF1 knockdown, RANBP2 was identified as the key target of YTHDF1 in cervical cancer cells. YTHDF1 regulated RANBP2 translation in an m⁶A-dependent manner without effect on its mRNA expression. RANBP2 potentiated the growth, migration and invasion of cervical cancer cells. Our study demonstrated the oncogenic role of YTHDF1 in cervical cancer by regulating RANBP2 expression and YTHDF1 represents a potential target for cervical cancer therapy.