Abstract
Evidence exists suggesting tumor-inhibiting properties of deubiquitylase OTUD1 in various malignancies. We herein investigated the anti-tumor effect and clarified the downstream mechanisms of OTUD1 in the chemoresistance of non-small cell lung cancer (NSCLC) cells. Expression of OTUD1 was examined in NSCLC (PC-9 cells) and erlotinib-resistant NSCLC (PC-9/ER) cell lines. OTUD1 was bioinformatically predicted to be weakly expressed in NSCLC tissue samples and verified in PC-9/ER cells. PC-9/ER cells were subsequently subjected to ectopic expression of OTUD1 alone or combined with SOX9 to dissect out the effect of OTUD1 on the proliferation, chemoresistance and apoptosis in vitro and in vivo. OTUD1 upregulation sensitized NSCLC cells to erlotinib both in vitro and in vivo. In the presence of OTUD1 overexpression, nuclear translocation of YAP1 was inhibited and its expression was inactivated. This effect of OTUD1 was associated with the decreased ubiquitination level of YAP1. SOX9/SPP1 inactivation was the consequence of inhibited nuclear translocation of YAP1. Overexpression of SOX9 reversed the inhibitory effect of OTUD1 on the resistance of NSCLC cells to erlotinib. In conclusion, our study reveals that OTUD1 potentially acts as a tumor suppressor and suppresses erlotinib resistance of NSCLC through the YAP1/SOX9/SPP1 axis, suggesting that OTUD1 may serve as a target for reducing chemoresistance for NSCLC.