MicroRNA-138 targets SOX4 to regulate the proliferation and metastasis of human lung cancer cells.

Purpose: The current study was set with a purpose to assess the regulatory role of micro RNA (miR)-138 in human lung cancer cells with emphasis on the underlying mechanism of action.

Methods: RT-PCR based analysis was employed for gene expression studies. MTT assay was used to determine the proliferation rates of lung cancer cells. Colony forming assay was performed for the analysis of colony forming potential. DAPI and Annexin V-FITC/propidium iodide (PI) double staining methods were performed for the analysis of apoptosis. Migration and invasion of cancer cells were assessed using wound healing and transwell assays, respectively. Dual luciferase reporter assay was performed for interactional study. Western blotting was used to determine the protein concentrations.

Results: Cancer cells had lower levels of miR-138 transcripts. The overexpression of miR-138 reduced the proliferation of cancer cells and cells were seen to form lower number of viable colonies. This was due to the induction of cancer cell apoptosis under miR-138 overexpression. miR-138 also inhibited the metastasis of lung cancer cells. miR-138 was found to interact with SOX4 intracellularly and SOX4 protein levels decreased under miR-138. The anticancer effects of miR-138 were shown to be modulated through SOX4.

Conclusion: MiRs have a potential to act as molecular markers in cancer prognosis. There is a need to screen for miRs specific to particular types of cancer and to look for their potential to function as anticancer entities at molecular level.