MicroRNA function in cancer: oncogene or a tumor suppressor?
MicroRNAs (miRNAs) are small noncoding, double-stranded RNA molecules that can mediate the expression of target genes with complementary sequences. About 5,300 human genes have been implicated as targets for miRNAs, making them one of the most abundant classes of regulatory genes in humans. MiRNAs recognize their target mRNAs based on sequence complementarity and act on them to cause the inhibition of protein translation by degradation of mRNA. Besides contributing to development and normal function, microRNAs have functions in various human diseases. Given the importance of miRNAs in regulating cellular differentiation and proliferation, it is not surprising that their misregulation is linked to cancer. In cancer, miRNAs function as regulatory molecules, acting as oncogenes or tumor suppressors. Amplification or overexpression of miRNAs can down-regulate tumor suppressors or other genes involved in cell differentiation, thereby contributing to tumor formation by stimulating proliferation, angiogenesis, and invasion; i.e., they act as oncogenes. Similarly, miRNAs can down-regulate different proteins with oncogenic activity; i.e., they act as tumor suppressors. This review will highlight the recent discoveries regarding miRNAs and their importance in cancer.
Shenouda
Sylvia K
SK
Department of Biochemistry and Molecular Biology, Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, 1901 Perdido Street, New Orleans, LA 70112, USA.
Alahari
Suresh K
SK
D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D048429:Cell Size; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D008297:Male; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000648:ultrastructure; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009369:Neoplasms / Q000235:genetics; D009857:Oncogenes; D012319:RNA Polymerase II / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012334:RNA, Neoplasm / Q000235:genetics / Q000502:physiology
D035683:MicroRNAs; D009363:Neoplasm Proteins; D012334:RNA, Neoplasm; D012319:RNA Polymerase II