Journal of Molecular Biomarkers and Clinical Trials

miRNA Roles: Sequence Analyses of Oncogenic and Tumor Suppressive miRNAs

* Shigeru Takasaki
Department Of Molecular Biomarkers, Japan , Japan

*Corresponding Author:
Shigeru Takasaki
Department Of Molecular Biomarkers, Japan , Japan
Email:s_takasaki@toyo.jp

Published on: 2018-04-27

Abstract

MicroRNAs (miRNAs) are small (∼25 nucleotides) noncoding RNA molecules thought to play an important role in regulating gene expression. Knowledge of the biological functions of most miRNAs is still limited, but these miRNAs are thought to regulate the gene expression in various diseases. In this paper the relations between the sequences of cancer-related miRNAs (both oncogenic and tumor suppressive) and those of control miRNAs in human beings are examined from the viewpoint of nucleotide frequencies at individual positions. Oncogenic and tumor suppressive miRNAs are involved in the overexpression/upregulation and underexpression/downregulation of cancers, whereas control miRNAs are not involved in cancer development and progression. The 132 oncogenic, 111 tumor suppressive, and 1610 control miRNA sequences investigated in this work were collected from miRBase on the basis of the relations between miRNAs of Homo sapiens and various cancers in the literature. Statistical analyses of the positional nucleotide occurrence features revealed clear differences between the cancer-related and control miRNAs. This indicates that miRNAs can be used as biomarkers in human cancers.

Keywords

miRNA; Noncoding RNA; Gene Silencing; Cancer; Oncogenic; Tumor Suppressive; Significance Test; Biomarker

Introduction

MicroRNAs (miRNAs) are small (∼25 nucleotides) noncoding RNA molecules that regulate gene expression post-transcriptionally by base-pairing to mRNAs [1-5].Many miRNAs have recently been identified in various multicellular organisms and are evolutionally conserved. Although knowledge of the biological functions of most miRNAs is still limited, these molecules are thought to regulate the gene expression at various stages in diseases.