The role of PIMREG in DNA damage accumulation in glioblastoma cells treated with temozolomide

Abstract

PIMREG (PICALM interacting mitotic regulator) is a nuclear protein enriched at the nucleolus. It is a substrate of the anaphase promoter/cyclosome complex (APC/C), which controls the transition from metaphase to anaphase. We have recently shown that PIMREG is upregulated in several types of cancer, with higher expression in glioblastoma (GBM). Moreover, our data suggests that PIMREG may play a role in DNA damage response (DDR) in GBM cells treated with chemotherapy and in DNA repair by Homologous Recombination (HR). Seeking to understand the role of PIMREG in DDR in GBM cells after the treatment with temozolomide (TMZ), T98G and U87MG cell lines wild type and knockout for PIMREG will be used in assays that aim to investigate the impact of PIMREG's deletion in the distribution and activation of proteins involved in DDR, as well in the accumulation of double strand breaks (DSBs), single strand breaks (SSBs) and chromosome breaks after the damage induction with TMZ. For this purpose, we plan to perform experiments such as immunofluorescence, targeting the proteins involved in DDR, DNA fragmentation, TUNEL, IdU incorporation and micronuclei assay, for the evaluation of DSBs, SSBs and chromosome breaks. Besides that, PIMREG' interactome will be characterized, after the treatment of GBM cells (T98G and U87MG) with TMZ, by proteomics analysis. The data that will be used in this experiment was produced previously by the student in a BEPE internship. With a greater understanding of PIMREG's role in DDR we aim to elucidate possible mechanisms of resistance in GBM in the face of treatment with chemotherapy.