# YTHDF3 suppresses interferon-stimulated gene (ISG)-dependent antitumor immunity and promotes HPV carcinogenesis in cervical cancer

## TL;DR

This study shows that YTHDF3 suppresses antiviral immunity and promotes cervical cancer caused by HPV by regulating RNA modifications and immune cell infiltration.

## Contribution

The novel finding is that YTHDF3 promotes HPV carcinogenesis by suppressing ISG responses through m6A-dependent regulation of STAT3.

## Key findings

- YTHDF3 suppresses type I ISG responses by stabilizing STAT3 mRNA through m6A modification.
- YTHDF3-STAT3 axis represses IRF7 and IFN-α production, weakening antiviral immunity in HPV+ cancer.
- Ythdf3−/− mice showed reduced immunosuppressive immune cells and enhanced CD8+ T cell activation in tumors.

## Abstract

Interferon-stimulated genes (ISGs) serve as evolutionarily conserved mediators of antiviral defense and tumor surveillance. Emerging evidence underscores the non-oncogenic addiction of high-risk human papillomavirus (hrHPV) E6/E7 oncoproteins in maintaining malignant phenotypes and cervical carcinogenesis. Here, we leveraged CRISPR/Cas9-engineered YTHDF3-knockout (YTHDF3−/−) SiHa cells and Ythdf3−/− mice to dissect the molecular arbiters governing m6A-dependent RNA regulation in HPV-driven carcinogenesis. To further elucidate the role of YTHDF3 in HPV-induced immunosuppressive tumor microenvironment (ITME) formation, we demonstrated that YTHDF3, an m6A RNA reader, suppresses type I ISGs responses. Notably, elevated m6A modification and YTHDF3 protein levels were observed in HPV+ CCa tissues. Mechanistically, YTHDF3 bound to the m6A methylation site of STAT3 mRNA, enhancing its stability and transcription efficiency. This YTHDF3-STAT3 axis repressed ISG (e.g., IRF7) transcription and IFN-α production, thereby compromising antiviral immunity and facilitating HPV E6/E7 persistence. Correspondingly, Ythdf3− mice bearing TC-1 xenografts exhibited a significant reduction in immunosuppressive immune cell infiltration, including Tregs, M2 macrophages, and MDSCs, accompanied by enhanced CD8+ T cell activation. Collectively, our findings unveiled that YTHDF3-mediated upregulation of STAT3 suppresses the type I ISG expression, thus promoting HPV carcinogenesis and establishing an ITME. Taken together, our results suggest that targeting the YTHDF3/STAT3/IRF7 axis could be a promising therapeutic strategy against HPV-associated malignancies.