Pellino-1 confers chemoresistance in lung cancer cells by upregulating cIAP2 through Lys63-mediated polyubiquitination

Pellino-1 is an E3 ubiquitin ligase that mediates immune receptor signaling pathways. The role of Pellino-1 in oncogenesis of lung cancer was investigated in this study. Pellino-1 expression was increased in human lung cancer cell lines compared with non-neoplastic lung cell lines. Pellino-1 overexpression in human lung cancer cells, A549 and H1299 cells, increased the survival and colony forming ability. Pellino-1 overexpression in these cells also conferred resistance to cisplatin- or paclitaxel-induced apoptosis. In contrast, depletion of Pellino-1 decreased the survival of A549 and H1299 cells and sensitized these cells to cisplatin- and paclitaxel-induced apoptosis. Pellino-1 overexpression in A549 and H1299 cells upregulated the expression of inhibitor of apoptosis (IAP) proteins, including cIAP1 and cIAP2, while Pellino-1 depletion downregulated these molecules. Notably, Pellino-1 directly interacted with cIAP2 and stabilized cIAP2 through lysine63-mediated polyubiquitination via its E3 ligase activity. Pellino-1-mediated chemoresistance in lung cancer cells was dependent on the induction of cIAP2. Moreover, a strong positive correlation between Pellino-1 and the cIAP2 expression was observed in human lung adenocarcinoma tissues. Taken together, these results demonstrate that Pellino-1 contributes to lung oncogenesis through the overexpression of cIAP2 and promotion of cell survival and chemoresistance. Pellino-1 might be a novel oncogene and potential therapeutic target in lung cancer.