Metformin-induced E6/E7 inhibition prevents HPV-positive cancer progression through p53 reactivation

The human papillomavirus (HPV) is implicated in multiple lethal cancers, although it is more sensitive to certain therapies than HPV-negative cancers. Therefore, the development of more targeted therapeutic strategies is imperative. The HPV oncogenes E6/E7 are ideal targets for HPV-positive cancer, but there are no clinical strategies that have been proven to effectively target E6/E7. Notably, metformin significantly inhibits E6/E7 expression; however, the underlying mechanism and therapeutic potential remain unclear, limiting its clinical translation. Cell Counting Kit-8, ethynyl-2'-deoxyuridine, and terminal-deoxynucleotidyl transferase-mediated Nick end labeling assays were conducted to evaluate the effects of metformin on cell viability, proliferation, and apoptosis. Quantitative real-time PCR, western blotting, and immunofluorescence assays were performed to determine changes in E6/E7 and p53 expression levels following metformin treatment. Patient-derived organoids and in-vivo xenograft models were constructed to evaluate the anticancer activity of metformin against HPV-positive cancer. Our research demonstrated enhanced sensitivity of HPV-positive cancer cells to metformin. Mechanistic studies have revealed that metformin exerts anticancer effects by inhibiting E6/E7 expression, which is associated with p53 reactivation. Furthermore, we substantiated the anticancer potential of metformin in HPV-positive patient-derived organoids and in-vivo tumor models. Our study focused on the mechanism underlying the enhanced responsiveness of HPV-positive cancer to metformin, highlighting the clinical potential of metformin as a targeted therapeutic strategy for HPV-positive cancer.