Role of transcription regulatory complexes and epigenetic modifications in driving the cell fate decisions

Specific transcription factors and co-regulatory proteins cooperate to regulate the expression of phenotypic genes involved in driving the specific cell lineage. Epigenetic mechanisms such as histone and DNA CpG-methylation that are controlled by regulatory complexes, also contribute in regulating cell fate decisions by regulating cellular transcription. During cancer a transformed cell faces cascade of external and internal signaling events that cause disruption of regulatory complexes and lead to failure of transcriptional machinery to run microenvironment. In general, together perturbation of transcriptional and epigenetic events in a cancer cell results in abnormal regulation of cell proliferation, growth and differentiation. These major biological mechanisms regulate tumor growth and progression during cancer. Recent findings have explored the existence of cancer "stem-like" cells in the tumor that are resistant to chemo-therapy and radio-therapy. These "stem-like" cells can be identified in the tumor due to the expression of marker genes and epigenetic modifications. Many specific post-translational epigenetic modifications such as, acetylation, methylation and phosphorylation of the histones are linked to transcriptional regulation of cancer "stem-like" phenotype. The current review briefly summarizes the importance of transcriptional regulatory complexes, epigenetic markings and molecular events involved in "stem-like" cell fate determination during cancer.