Tumor suppressor TAp73 is required to maintain pluripotency of cancer stem cells

Cancer stem cells (CSCs) are resistant to conventional chemotherapy and are hence responsible for cancer relapse. Pluripotency is a characteristic of CSCs which allows them to rapidly proliferate while maintaining the ability to differentiate into various lineages. We found that TAp73, but not its homologue p53, is required for the pluripotency of CSCs. TAp73 knockdown (KD) decreased SOD1 levels, increased ROS production and disturbed metabolism which induced differentiation and abrogated pluripotency in CSCs. TAp73 related decrease in pluripotency is linked to increased autophagy and senescence in CSCs. Furthermore, TAp73 KD also decreased the levels of pluripotency factor Sox-2 within heterogeneous cancer cell lines. Interestingly, TAp73-deficient CSCs strongly lose tumorigenic potential in mice and tumors that did form had significantly lower levels of SOD1 and pluripotency marker Oct4. Our findings reveal a unique role of TAp73 in CSCs development that is important to consider while devising future therapeutic strategies against cancer.