MicroRNAs are novel small noncoding RNA molecules that regulate gene expression at the post-transcriptional level. Compelling evidence reveals that there is a causative link between microRNAs deregulation and cancer development and progression. The present study aims to explore the function of miR-206 in the proliferation, apoptosis, motility, and invasion of nonsmall cell lung cancer. Using real-time PCR, we detected the miR-206 expression of normal lung tissues, tumor tissues, human normal bronchial epithelial cell line, and six lung cancer cell lines (LCCLs). Then, we evaluated the role of miR-206 in cell proliferation, apoptosis, and invasion using Cell Counting Kit-8 assay, Annexin-V/FITC assay, wound healing, and Transwell assay in LCCLs. As a result, miR-206 expression level was lower in high metastasis tumors and 95D than low metastasis tumors and normal lung tissues as well as other LCCLs. After miR-206 was upregulated in LCCLs, cell proliferation was notably attenuated and apoptosis was significantly increased. Furthermore, overexpression of miR-206 inhibited migration and invasion of lung cancer cells. In conclusion, our data suggest that expression level of miR-206 was inversely correlated with metastatic potential of lung cancer. Anat Rec, 294:88-92, 2011. V V C 2010 Wiley-Liss, Inc.

Background/Aims: Circular RNAs (circRNAs) act as microRNA (miRNA) sponges that regulate gene expression and are involved in physiological and pathological processes. In this study, we evaluated the roles of circRNAs in the chemoresistance of non-small cell lung cancer (NSCLC) to taxol. Methods: High-throughput circRNA microarrays were employed to investigate the circRNA profiles of parental A549 and taxol-resistant A549/Taxol cells. We predicted the miRNA targets of differentially expressed circRNAs via miRNA prediction software and then constructed a circRNA/miRNA network using Cytoscape. Bioinformatics analyses were performed to annotate dysregulated circRNAs in detail. Results: We detected 2909 significantly upregulated and 8372 downregulated circRNAs in A549/Taxol cells compared with A549 cells. The circRNA/miRNA network displayed their interactions, suggesting that circRNAs exert biological effects by absorbing and sequestering miRNA molecules. Computational Gene Ontology and pathway analyses were used to determine the biological function and signaling pathways of host genes of dysregulated circRNAs and to identify potential molecular mechanisms prompting the resistance of NSCLC to taxol. Conclusion: This study focusing on circRNAs related to taxol resistance provides a basis for clarifying the development and progression of drug resistance and for identifying therapeutic targets in NSCLC.

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It is well‐known that phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor which negatively regulates PI3K/AKT signaling and is activated widely in non‐small cell lung cancers (NSCLC). However, genetic alterations in PTEN genes are rare, suggesting an undefined mechanism(s) for their suppression. Notably, growing evidence indicates that PTEN can be regulated by microRNAs involved in cancer progression. In this study, we discover that the miR‐4286 is overexpressed in NSCLC and negatively regulates the expression of PTEN. Furthermore, we found that miR‐4286 reduces PTEN expression by directly binding to PTEN 3′‐untranslated region (UTR), thereby inhibiting NSCLC cell proliferation and mobility. Moreover, mechanistic investigations revealed that miR‐4286 overexpression was a result of PTEN‐mediated activation of the PI3K/AKT pathway. Taken together, our findings elucidate that miR‐4286 promotes the tumorigenesis of NSCLC by interacting with PTEN. This miR‐4286‐mediated upregulation of PTEN might lead to new therapeutic strategies for NSCLC.