Abstract 127: MicroRNA-328 is associated with non-small cell lung cancer (NSCLC) brain metastasis and mediates NSCLC migration

Abstract

Abstract Background: Lung cancer is the leading cause of cancer deaths and ∼88% of patients with primary lung malignancy have non-small cell lung cancer (NSCLC). Brain metastasis (BM) can affect up to 25% of these patients during their lifetime. There is surely a need for improvement in patient stratification to identify lung cancer patients at higher risk of developing BM. Recently, microRNAs (miRNAs) have been studied to characterize tumors. We investigated miRNAs that may serve as biomarkers to differentiate between NSCLC patients with and without BM. Experimental Design: A miRNA brain metastasis classifier described in Nasser et al was validated on a set of 15 other patients(ref1). Following these experiments, miR-328 (one of the two markers that could successfully classify BM+ cases) was over-expressed in A549, a NSCLC cell line, using a lentiviral system. These miR-328 over-expressing cells were then used for gene expression studies using Agilent microarrays. These cells were also used for cell migration studies. Transient transfection of gene specific siRNA was used to demonstrate the role of PRKCA (gene upregulated in miR-328 over-expressing cells) in migration of NSCLC cells. Results: A miRNA classifier was built based on 12 samples from clinically matched NSCLC from patients with BM (BM+) and without BM (BM-)(ref1). This classifier consisting of miR-328 and miR-330-3p expression was able to correctly classify BM+ vs. BM- patients. It was then used on a validation cohort and correctly classified 12/15 patients. Comparison of gene expression profiles of A549 parental and A549 cells stably transfected to over-express miR-328 (A549-328) identified several significantly differentially-expressed genes. PRKCA was one of the genes upregulated in A549-328 cells. Its upregulation in A549-328 cells was confirmed at the protein level by western blotting. A549-328 cells have significantly increased cell migration compared to A549 cells, and knockdown of PRKCA by transient siRNA transfection leads to significant reduction in this migration potential. Conclusion: miR-328 has a role in conferring migratory potential to NSCLC cells working in part through PRKCA. With further corroboration, these miRNAs may be incorporated into clinical treatment decision-making to stratify NSCLC patients at higher risk for developing brain metastasis. Reference 1. Nasser S, Ranade A, Sridhar S, Haney L, Korn RL, Gotway MB, Weiss GJ, Kim S. Identifying MiRNA and Imaging Features Associated with Metastasis of Lung Cancer to the Brain. Proceedings of the IEEE International Conference on Bioinformatics & Biomedicine 2009:246-51. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 127. doi:10.1158/1538-7445.AM2011-127