Abstract:
Cancer is disease of uncontrolled growth of poorly differentiated cells that lose their ability to commit suicide when cells are attacked by exogenous or endogenous stresses. Amongst all cancers, Breast cancer is ranked at third position and is the fifth highest cause of mortality. Of all the DNA damages occurring in the genomic content, double strand breaks (DSBs) are most lethal and major cause of cancer. DSBs are either repaired by Homologous Recombination (HR) or Non-Homologous End Joining pathway (NHEJ). Artemis and DNA-PKcs are the key players in NHEJ to repair the DSBs. p53 is downstream phosphorylation target of DNA-PKcs and decides the fate of cell towards apoptosis if DNA damage is not repaired. The aim of this study was to determine the relationship of Artemis with DNA-PKcs and p53 and their effect on cell death and chromosomal aberrations after inhibition of Artemis in breast cancer cells of local population and to provide the cancer world with a new therapeutic target. Samples of invasive ductal carcinoma were collected from different hospitals and processed in laboratory to develop primary cell line. siRNA mediated inhibition of Artemis was done and semi-quantitative analysis of Artemis, DNA-PKcs and p53 was determined by analyzing gel bands on ImageJ. Data suggested that p53 gene level was increased after Artemis inhibition whereas, minimal change in DNA-PKcs levels were observed. To confirm the relationship between Artemis, p53 and apoptosis, MTT assay was performed. The results provided the evidence with significant decrease in percentage viability of cancerous cells which showed some direct relationship between Artemis and p53. Chromosomal aberrations were checked by metaphase spread and increased genomic aberrations were observed after Artemis inhibition, these results were also in concordance with unpublished results of DNA damage obtained from Comet assay. In conclusion, study provided with the direct relationship of Artemis, DNA-PKcs and p53 in DNA repair after Artemis inhibition. Artemis could be a new therapeutic target in order to increase the cell death in cancerous cells by activating p53. Moreover, this study has provided with new path to determine the underlying mechanisms in NHEJ.
