OBJECTIVETo investigate the role of wild-type p53-induced gene 1 (WIG-1) on the regulation of multi-drug resistance in small cell lung cancer.

METHODSThe expressions of WIG-1 protein and gene were detected by Western blot and real-time PCR (RT-PCR) in both the drug-sensitive H69 and drug-resistant H69AR cell lines, respectively. Meanwhile, the differential expression of WIG-1 was also detected in peripheral blood samples of responders and non-responder patients. Furthermore, the WIG-1 expression was inhibited by siRNA in H69AR cells, then the drug-sensitivities of H69AR cells to chemotherapy agents such as ADM, DDP, VP-16 were detected by CCK8 assay, and apoptosis rate was detected by flow cytometry. The possible association of WIG-1 with clinical parameters was evaluated.

RESULTSThe expression of WIG-1 was significantly increased in H69AR cells (5.965 ± 0.890) than that in the H69 cells (1.023 ± 0.127) (P = 0.007). The expression of WIG-1 was significantly increased in the non-responder patients (4.169 ± 0. 970) than in the H69 cells and responders (1.673 ± 0.127) (P < 0.001). The drug-sensitivities of H69AR cells to chemotherapeutic drugs were increased when the expression of the WIG-1 was down-regulated. The apoptosis rate was significantly decreased in the H69AR cells (1.037 ± 0.049)% compared with that in the H69 cells [(7.963 ± 0.097)%, (P < 0.01)]. The apoptosis rate was increased in the H69AR-Si-WIG-1 cells (20.915 ± 0.890)% than that of (1.037 ± 0.049)% in the H69AR and H69AR-NC group (2.025 ± 0.097)% (P < 0.01). The expression of WIG-1 was not significantly associated with gender, and age (P > 0.05), but significantly correlated with chemosensitivity, overall survival and clinical stage (P < 0.001 for all).

CONCLUSIONSOur results suggest that WIG-1 is involved in the regulation of the multidrug resistance mechanism in small cell lung cancer. Selective silencing of the WIG-1 gene may reverse the multidrug resistance of SCLC via increasing cell apoptosis.