Inhibition of nonhomologous end joining to increase the specificity of CRISPR/Cas9 genome editing.

DNA repair, one of the fundamental processes occurring in a cell, safeguards the genome and maintains its integrity. Among various DNA lesions, double-strand breaks are considered to be the most deleterious, as they can lead to potential loss of genetic information, if not repaired. Nonhomologous end joining (NHEJ) and homologous recombination are two major double-strand break repair pathways. SCR7, a DNA ligase IV inhibitor, was recently identified and characterized as a potential anticancer compound. Interestingly, SCR7 was shown to have several applications, owing to its unique property as an NHEJ inhibitor. Here, we focus on three main areas of research in which SCR7 is actively being used, and discuss one of the applications, i.e. genome editing via CRISPR/Cas, in detail. In the past year, different studies have shown that SCR7 significantly increases the efficiency of precise genome editing by inhibiting NHEJ, and favouring the error-free homologous recombination pathway, both in vitro and in vivo. Overall, we discuss the current applications of SCR7 to shed light on the unique property of the small molecule of having distinct applications in normal and cancer cells, when used at different cellular concentrations.