MicroRNAs and Cancer Stem Cells

Abstract

MicroRNAs (miRNAs) are a class of non-coding RNAs that are believed to play important roles during tumorigenesis and cancer metastasis. Growing evidence has shown altered regulation of miRNAs in cancer stem cell populations. In this chapter, the expression profiles of miRNA in embryonic stem cells and cancer stem cells are summarized. The individual miRNAs which may regulate cancer stem cells and their target genes are described. Several miRNAs, including miR-302 and miR-181, function to promote the cancer stem cell phenotype. Conversely, other miRNAs including let-7, miR-145, miR-200 family, miR-203, miR-128, miR-34, and miR-199b, suppress stemness and promote differentiation of cancer stem cells. The recent evidence for a role of miRNA in regulating cancer stem cells, epithelial-mesenchymal transition, and cancer metastasis are described. We introduce the potential of miRNA for cancer diagnostics and therapeutics based on current tests and studies of miRNA treatment on cancer. The current challenges to apply miRNA-based cancer therapeutics are also discussed with an emphasis on recent evidence for miRNA-mediated heterotypic signals. The miRNA regulation of factors that are secreted into the blood stream creates an attractive new approach to managing miRNA-driven disease processes.