Identification of microRNA profiles in docetaxel-resistant human non-small cell lung carcinoma cells (SPC-A1)

Docetaxel has been used as first-line chemotherapy in advanced non-small cell lung carcinoma (NSCLC), but further extensive and effective application is prevented by drug resistance. MicroRNAs (miRNAs) have recently been identified as important posttranscriptional regulators, which are involved in various biological processes. The aim of this study was to identify microRNA expression profiles involved in the development of docetaxel resistance in NSCLC. Here, microarray chip technology was employed to identify miRNA expression profiles in docetaxel-resistant human NSCLC cell line (SPC-A1/docetaxel). Then, the changes of miRNAs expression (>2-fold compared with control SPC-A1 cell line) were testified by quantitative real-time RT-PCR (qRT-PCR) assay. Furthermore, the potential target genes regulated by selected miRNAs were analysed by various target prediction tools. The expression of a total of 52 miRNAs showed significant difference between SPC-A1/docetaxel cells and control SPC-A1 cells (P < 0.01). Six miRNAs (miR-192, 200b, 194, 424, 98 and 212) exhibited more than 2-fold changes in their expression levels, which were validated by qRT-PCR. The expression of three miRNAs (miR-200b, 194 and 212) was significantly down-regulated in SPC-A1/docetaxel cells, while the expression of other three miRNAs (miR-192, 424 and 98) was significantly up-regulated in SPC-A1/docetaxel cells (P < 0.01). Potential target genes controlled by six selected miRNAs were divided into four groups according to various functions: apoptosis and proliferation (71 genes), cell cycle (68 genes), DNA damage (26 genes) and DNA repair (59 genes). The expression of a few target genes in SPC-A1/docetaxel and SPC-A1 cells were further confirmed by qRT-PCR and Western blot. Taken together, the identification of microRNA expression profiles in docetaxel-resistant NSCLC cells could provide a better understanding of mechanisms involved in drug sensitivity or resistance, which would be helpful to develop novel strategies for targeted therapies in chemorefractive NSCLC patients.