Epigenetic modification: key regulator of reprogramming in cancer stem cells

Cancer stem cells (CSCs) are tumor subsets that can self-renew, differentiate into various tumor lineages, and induce dynamic cellular phenotypic changes from epithelial to mesenchymal transition responsible for drug resistance and cancer relapse. Metastasis and malignancy are regulated by network of molecular mechanism. Heterogeneity of CSCs depends on plasticity of CSCs controlled by DNA mutations, epigenetic changes, and genomic rearrangements in several signaling pathways. The machinery of epigenetics potentiates reprogramming of heterogeneous tumor phenotype into homogeneous normal cells by DNA methylation, histone deacetylation, and noncoding RNAs, which are of therapeutic interest to target CSCs. The treatment strategies started aiming to control the link of formation, maintenance, activation, and transformation of CSCs using epigenetic drugs. The advancement of treatment with targeted mechanisms includes several epigenetic inhibitors in clinical trials. This book chapter focuses on the underlying epigenetic reprogramming mechanisms in CSCs with respect to treatment strategies and therapies employed in research and progressed into clinical trials.