Since its discovery in 1979, p53 has become the focus of intensive cancer-based research in laboratories around the world. The p53 protein mediates critical cellular functions including the response to genotoxic stress, differentiation, senescence, and apoptosis, and has been shown to be mutated in a large proportion of human cancers. These observations led many to speculate that targeting the p53 pathway would result in the development of successful anti-cancer treatments. In spite of this, 30 years later, p53 has yet to fulfill this promise. However, new insights into small molecule combination therapies, microRNA regulation, structuring of clinical trials, and potential involvement in stem cell regulation may help p53 reach its potential.

from Nikolas Desilet, Tessa N. Campbell and Francis Y.M. Choy in Current Issues in Molecular Biology

Further reading: p53-based Anti-cancer Therapies: an Empty Promise?

Labels: Anti-cancer treatment, Apoptosis, Differentiation, Enotoxic stress, microRNA, MicroRNA regulation, p53, p53 pathway, p53 protein, Senescence

MicroRNAs are short, ~22 nucleotide regulatory RNAs, first discovered in Caenhorhabditis elegans. Hundreds of microRNAs have been identified in plants and animals. Based on the current number of predicted microRNAs, one to three percent of genomic DNA is believed to encode these small, regulatory RNAs.

MicroRNAs inhibit protein synthesis by binding to their target mRNAs and regulating gene expression in a post-transcriptional manner. The exact mechanism by which target gene expression is down-regulated is unclear; however, experimental evidence has led to several different theories to explain microRNA-mediated mRNA repression. These possible mechanisms include target degradation, localization to P-bodies, inhibition of translation initiation or elongation, mRNA deadenylation, and mRNA destabilization.

from Chin and Slack in RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity

Further reading: RNA and the Regulation of Gene Expression

Labels: gene regulation, microRNA, mRNA, regulation, RNA