Analysis of changes in MALAT1 long non coding RNA and miR-30b in tumor tissue and free margin in patients with lung cancer

Abstract

Due to poor prognosis and treatment failure, lung cancer is still the most prevalent and lethal malignancy, worldwide. Aberrant methylation and expression of various noncoding RNAs, including microRNAs and lncRNAs possesses great potential as tumor markers. Considering that in the current study, changes in MALAT1 lncRNA expression and miR-30b methylation was investigated in lung cancer as a promising detection biomarker.

Methods: miR-30b DNA methylation and MALAT-1 expression pattern were first explored using microarray data retrieved from the non-small cell Lung Cancer (NSCLC) dataset in Cancer Genome Atlas (TCGA). Then, the obtained results were further validated in internal samples, including NSCLC tissue samples and adjacent normal tissues. Subsequently, genomic DNA was extracted and modified by sodium bisulfite while total RNA was reverse transcribed to cDNA. Finally, qRT-PCR and q-MSP methods were carried out to evaluate gene expression and DNA methylation, respectively.

Results: Our results evidenced significant miR-30b hypomethylation and lncRNA MALAT-1 overexpression in NSCLC samples in comparison with marginal normal samples. Besides, it was shown that these changes were significantly correlated with advanced stage of malignancy. Also, using ROC curve analysis, miR-30b methylation and MALAT-1 expression pattern were found as possible diagnostic biomarkers for NSCLC, considering AUC values equal to 0.67 and 0.70, respectively. A significant relationship was found between miR-30b hypomethylation and lncRNA MALAT-1 overexpression.