Biological and clinical relevance of correlated expression levels of coding and long noncoding RNAs in HPV16 positive cervical cancers.

Abstract

Human papillomavirus (HPV) drives cervical cancer (CaCx) pathogenesis and viral oncoproteins jeopardize global gene expression in such cancers. In this study, our aim was to identify differentially expressed coding (DEcGs) and long noncoding RNA genes (DElncGs) specifically sense intronic and Natural Antisense Transcripts as they are located in the genic regions and may have a direct influence on the expression pattern of their neighbouring coding genes. We compared HPV16-positive CaCx patients (N = 44) with HPV-negative normal individuals (N = 34) by employing strand-specific RNA-seq and determined the relationships between DEcGs and DElncGs and their clinical implications. By performing Gene set enrichment and protein-protein interaction (PPI) analyses of DEcGs, we identified enrichment of processes crucial for abortive virus life cycle and cancer progression. The DEcGs formed 16 gene clusters which we identified through Molecular Complex Detection (MCODE) plugin of Cytoscape. All the gene clusters portrayed cancer-related functions. We recorded significantly correlated expression levels of 79 DElncGs with DEcGs at proximal genomic loci based on Pearson's Correlation coefficients. Of these gene pairs, 24 pairs portrayed significantly altered correlation coefficients among patients, compared to normal individuals. Of these, 6 DEcGs of 6 such gene pairs, belonged to 5 of the identified gene clusters, one of which was survival-associated. Out of the 24 correlated DEcG: DElncG pairs, we identified 3 pairs, where expression of both members was significantly associated with patient overall survival. The findings justify the cooperative roles of these gene pairs, in patient prognostication, thereby bearing immense potential for translation. Thus, elucidation of correlative strengths between paired DElncGs and DEcGs in patient and normal samples, could serve as a foundation for identification of therapeutic and prognostic targets of HPV16-positive CaCx.