Therapeutic Role of MiR-140-5p for the Treatment of Non-small Cell Lung Cancer.

Lung cancer is the second most common cancer in both men and women, after prostate and breast cancer, respectively. There are two main types of primary lung cancer, non-small cell lung cancer (NSCLC), which accounts for approximately 85-90% of all lung cancer cases, and small cell lung cancer (SCLC), which accounts for the other 10-15% of lung cancers. MiRNAs are small molecules that post-transcriptionally regulate many genes and contribute to many disease aetiologies, including tumours. In lung cancer, the down-regulation of miR-140-5p leads to disease progression. In this study a miR-140-5p-only treatment and miR-140-5p combined with other chemotherapeutics have been studied in vitro. When transfected into NSCLC, the overexpression of miR-140-5p reduced the migration and invasion properties of malignant cells and, also improved their adhesion onto the artificial extracellular matrix. When miRNA-140-5p replacement treatment was combined with other drugs commonly used in clinical practice, such as gefinitib, DMH1 and cisplatin, it enhanced their efficacy by reducing the migration and invasion ability of cancer cells, thus suggesting that it acts synergistically with known compounds for the treatment of NSCLC. Additionally, some endothelial mesenchymal transition (EMT) markers appeared to be regulated by miR-140-5p. Novel direct targets of miR-140-5p have not been investigated in this study, but our results indicate the involvement of miR-140-5p in lung cancer invasion. The preliminary data from this study imply that when miR-140-5p levels are restored; maybe synergistically support current therapies for NSCLC though further validation, especially in vivo is required.