Abstract
BackgroundDevelopment of resistance to therapy continues to be a serious clinical problem in lung cancer management. We previously identified that Annexin A2 is significantly up-regulated in cisplatin-resistant non-small cell lung cancer (NSCLC) A549/DDP cells. However, the exact function and molecular mechanism of Annexin A2 in cisplatin resistance of NSCLCs has not been determined.MethodsWestern blot and qRT-PCR were performed to analyze the protein and mRNA level of indicated molecules, respectively. Immunohistochemistry was performed to analyze the expression of Annexin A2 in NSCLC tissue samples. MTS assay, Colony formation assays, AnnexinV/PI apoptosis assay, Luciferase Reporter Assay, Chromatin-immunoprecipitation, and nude mice xenograft assay were used to visualize the function of Annexin A2 on cisplatin resistance.ResultsOur results demonstrated that knockdown of Annexin A2 increased cisplatin sensitivity of cisplatin-resistant A549/DDP cells both in vitro and in vivo, whereas overexpression of Annexin A2 increased cisplatin resistance of A549, H460 and H1650 cells. Moreover, we found that Annexin A2 enhanced cisplatin resistance via inhibition of cisplatin-induced cell apoptosis. Our studies showed that Annexin A2 suppressed the expression of p53 through activation of JNK/c-Jun signaling, which in turn resulted in a decrease in the expression of p53-regulated apoptotic genes p21, GADD45 and BAX, as well as p53-dependent cell apoptosis. Furthermore, we found that in NSCLC cases that Annexin A2 is highly expressed; it is positively correlated with a poor prognosis, as well as correlated with short disease-free survival for patients who received chemotherapy after surgery.ConclusionsThese data suggested that Annexin A2 induces cisplatin resistance of NSCLCs via regulation of JNK/c-Jun/p53 signaling, and provided an evidence that blockade of Annexin A2 could serve as a novel therapeutic approach for overcoming drug resistance in NSCLCs.
Highlights
Development of resistance to therapy continues to be a serious clinical problem in lung cancer management
We found that knockdown of Annexin A2 by using specific small-interfering RNA (siRNA) against Annexin A2 significantly increased cisplatin sensitivity of A549/DDP cells compared with control siRNA (Fig. 1b, c)
We found that Annexin A2 activated c-Jun N-terminal kinase (JNK)/c-Jun signaling, which in turn leads to an decrease in p53 transcription
Summary
Development of resistance to therapy continues to be a serious clinical problem in lung cancer management. We previously identified that Annexin A2 is significantly up-regulated in cisplatin-resistant non-small cell lung cancer (NSCLC) A549/DDP cells. The exact function and molecular mechanism of Annexin A2 in cisplatin resistance of NSCLCs has not been determined. Lung cancer is a leading cause of cancer-related deaths worldwide, and non-small-cell lung cancer (NSCLC) accounts for approximately 80% of all cases of lung cancer [1]. Platinum-based drugs, cisplatin (DDP), are used in the treatment of many cancers, including NSCLC [3]. Annexin A2 is a calcium-dependent, phospholipidbinding cell surface protein which has diverse cellular functions, including membrane-cytoskeleton organization, vesicular trafficking, and regulation of ion channel activity [5].
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