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Background and purpose:MicroRNA (miRNA) belongs to a class of 19 to 30 nucleotide-long, endogenous noncoding RNA expressed in eukaryotes and predominantly inhibits gene expression at the post-transcriptional level. The miRNAs play critical roles in cell proliferation and differentiation, apoptosis, metabolism, and immune regulation. This study aimed to detect the expression of miR-216a-5p in lung cancer tissues and lung cancer cell lines, and to discuss the effects of miR-216a-5p on the invasion ability of lung cancer cells and the mechanism.Methods:Quantitative real-time PCR (qRT-PCR) was used to detect the expression of miR-216a-5p in lung cancer tissues of 55 cases and 7 lung cancer cell lines. Three lung cancer cell lines of A549, 95D and H460 were transiently transfected by miR-216a-5p, and Transwell was used to detect the effects of miR-216a-5p on the invasion of lung cancer cell lines. The dual luciferase reporter plasmids containing the miR-216a-5p candidate target gene and the gene of matrix metalloproteinase 16 (MMP16) were predicted and constructed. qRT-PCR and Western blot were used to detect the changes in mRNA and protein levels of target geneMMP16 by miR-216a-5p. The interference of MMP16 by siRNA and up-regulation miR-216a-5p by transfection were compared on the invasion of lung cancer cells.Results:The miR-216a-5p expression levels were all signiifcantly reduced in 90.91% (50 of 55 patients) tumor tissues compared with corresponding adjacent normal lung tissues (P<0.05). The miR-216a-5p expression levels were only 7.00%-32.00%in 7 lung cancer cells compared with the control group (P<0.05). Up-regulation of the expression of miR-216a-5p inhibited the invasion of lung cancer cells; interference of MMP16 by siRNA, as well as up-regulating miR-216a-5p by transfection, inhibited the expression of MMP16 in lung cancer leading to inhibition of the invasion of lung cancer cells. Conclusion:miR-216a-5p can be a candidate marker in clinical diagnosis and it can inhibit the invasion of lung cancer cells by down-regulating the expression of MMP16.
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<p><b>OBJECTIVE</b>To investigate the role of wild-type p53-induced gene 1 (WIG-1) on the regulation of multi-drug resistance in small cell lung cancer.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>The 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).</p><p><b>CONCLUSIONS</b>Our 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.</p>