Introduction: Receptor EphA2 is over expressed in NSCLC and is associated with tumor progression and poor survival. MicroRNAs (miRs) are short, non-coding RNAs that post-transcriptionally regulate gene expression. Dysregulated expression of miRs has been observed in variety of malignancies. However, the role of miR-331-5p in NSCLC growth and migration is not known. We hypothesized that EphrinA1 treatment promotes miR-331-5p expression in NSCLC and miR-331 may inhibit tumor growth and invasion by targeting receptor EphA2.

Methods: The A-549 and H-23 NSCLC cells were treated with Ephrin-A1 for 24 hr and the miR-331-5p expression was measured by real-time PCR analysis. EphA2 protein expression was studied through Western blotting analysis. The cell proliferation was studied by WST-1 assay. The tumor formation and invasion was determined by 3-D matrigel and Wound healing assays respectively. Luciferase assay was performed to confirm miR-331-5p as one of the direct and specific target for EphA2.

Results: The miR-331-5p expression was inversely correlated with EphA2 expression. Transfection of NSCLC with precursor miR-331-5p inhibited proliferation, and migration of NSCLC cells. In addition the ability of tumor colony formation was significantly inhibited when the cells were transfected with miR-331-5p precursors. We have identified predicted target binding site of EphA2 in its 3’ UTR region by miR-331-5p. This was confirmed by Luciferase assay. Over-expression of miR-331-5p in NSCLC cells repressed the endogenous levels of EphA2 protein.

Conclusion: This study for the first time reports, that miR-331-5p directly regulates EphA2 mRNA and protein expression in NSCLC. MiR-331 directly binds to 3’ -UTR region of EphA2 and inhibits tumor growth and migration. Our findings also provide an insight into the regulation of EphA2 expression and suggest that miR-331-5p has the capacity to regulate signalling pathways critical for the development and progression of NSCLC.

Funding: RC1 from Florida Department Health, and VA Merit

Citation Format: Bhagyalaxmi Sukka-Ganesh, Kamal A. Mohammed, Frederic Kaye, Najmunnisa Nasreen. MiR-331-5p targets receptor EphA2 and attenuates tumor growth and migration in NSCLC. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5346. doi:10.1158/1538-7445.AM2013-5346