Human U3 protein 14a plays an anti-apoptotic role in cancer cells.

Human U three protein 14a (hUTP14a) binds p53 and promotes p53 degradation. Here, we report that hUTP14a plays an anti-apoptotic role in tumor cells through a p53-independent pathway. Knockdown of hUTP14a activated the intrinsic pathway of apoptosis and sensitized tumor cells to chemotherapeutic drug-induced apoptosis. In addition, the protein level of hUTP14a decreased upon chemotherapeutic drug- or irradiation-induced apoptosis. Importantly, the decrease of hUTP14a during induced apoptosis was not blocked by pan-caspase inhibitor z-VAD-FMK, indicating that the down-regulation of hUTP14a is an upstream event in apoptosis. Furthermore, ectopically expressed hUTP14a protected tumor cells from chemotherapeutic drug-induced apoptosis. In summary, our data showed that hUTP14a protected tumor cells from chemotherapeutic drug-induced apoptosis and thus might possess a potential as a target for anti-tumor therapy.