Hypoxic HPV‐Positive Cancer Cells Are Particularly Sensitive to the Pro‐Senescent Effects of B‐MYB Repression Due to the Lack of Compensatory A‐MYB Induction

Tumor hypoxia is typically linked to increased therapy resistance and poor prognosis of many malignancies, including HPV-positive cancers. One possible resistance mechanism is the increased resistance of hypoxic tumor cells to cellular senescence. It is thus highly interesting to identify strategies which could increase their pro-senescent susceptibility. In comparative analyses of normoxic and hypoxic HPV-positive cancer cells, we here uncover that the interconnection between B-MYB and its paralog A-MYB plays a key role for their senescence response, but shows a differential regulation under normoxia and hypoxia. In specific, we demonstrate that the pro-senescent response to B-MYB loss is counteracted by a compensatory upregulation of A-MYB under normoxia. Therefore, efficient induction of senescence in normoxic cells requires the downregulation of both B-MYB and A-MYB. Interestingly, this compensatory A-MYB induction is absent under hypoxia, rendering hypoxic cancer cells particularly sensitive to the pro-senescent effect of B-MYB repression. We further show that these regulatory effects are not confined to HPV-positive cancer cells, indicating that they could be broadly conserved between different cancer types. Collectively, our findings reveal that hypoxic cancer cells are particularly sensitive to B-MYB inhibition, which could provide a new strategy to target this therapeutically challenging cancer cell population.