Dataset Information

PC4-mediated Ku PARylation facilitates NHEJ-dependent DNA damage repair

ABSTRACT: Radiotherapy is one of the mainstays for the treatment of hepatocellular carcinoma (HCC); however, a substantial fraction of HCC patients develops radioresistance and eventually suffer from tumour progression or relapse, a major impediment to the use of radiotherapy. One of the main goals in HCC management is to elucidate the mechanisms underlying radioresistance and identify novel therapeutic targets to improve the patients' prognosis. In this study, we report a DNA repair enhancer, human positive cofactor 4 (PC4), that promotes NHEJ-based DNA repair and renders HCC cells resistant to radiation. Mechanistically, PC4 interacts with PARP1 and directs Ku complex PARylation, resulting in successful recruitment of the Ku complex to damaged chromatin and increasing the efficiency of NHEJ repair. Clinically, PC4 is highly expressed in tumour tissues, which is correlated with poor prognosis in HCC patients. Taken together, our data suggest that PC4 is a DNA repair driver that can be targeted to radiosensitize HCC.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Hepatocyte, Cell Culture

SUBMITTER: Qimei Pan

LAB HEAD: Chummeng Shi

PROVIDER: PXD042218 | Pride | 2023-10-24

REPOSITORIES: Pride

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Publications

PC4-mediated Ku complex PARylation facilitates NHEJ-dependent DNA damage repair.

Pan Qimei Q Luo Peng P Shi Chunmeng C

The Journal of biological chemistry 20230710 8

Radiotherapy is one of the mainstay treatments for hepatocellular carcinoma (HCC). However, a substantial number of patients with HCC develop radioresistance and eventually suffer from tumor progression or relapse, which is a major impediment to the use of radiotherapy. Therefore, elucidating the mechanisms underlying radioresistance and identifying novel therapeutic targets to improve patient prognosis are important in HCC management. In this study, using in vitro and in vivo models, laser micr ...[more]

PMID: 37437887

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Project description:Purpose: Predominant causes of head and neck cancer recurrence after radiotherapy are rapid repopulation, hypoxia, fraction of cancer stem cells and intrinsic radioresistance. Currently, intrinsic radioresistance can only be assessed by ex-vivo colony assays. Besides being time-consuming, colony assays do not identify causes of intrinsic resistance. We aimed to identify a biomarker for intrinsic radioresistance to be used before start of treatment and to reveal biological processes that could be targeted to overcome intrinsic resistance. Experimental design: We analyzed both micro- and messenger RNA expression in a large panel of HNSCC cell lines. Expression was measured on both irradiated and unirradiated samples. Results were validated using modified cell lines and a series of laryngeal cancer patients. Results: MiRs, mRNAs and gene sets that correlated with resistance could be identified from expression data of unirradiated cells. The presence of epithelial to mesenchymal transition (EMT) and low expression of miRs involved in the inhibition of EMT were important radioresistance determinants. This finding was validated in two independent cell line pairs, in which the induction of EMT reduced radiosensitivity. Moreover, low expression of the most important miR (miR-203) was shown to correlate with local disease recurrence after radiotherapy in a series of laryngeal cancer patients. Conclusions: These findings indicate that EMT and low expression of EMT-inhibiting miRs, especially miR-203, measured in pre-treatment material, causes intrinsic radioresistance of HNSCC, which could enable identification and treatment modification of radioresistant tumors. Matched pairs of pre-treatment biopsies of 34 patients treated at The Netherlands Cancer Institute between 2002 and 2010. Patients with T2-3 laryngeal cancers, all treated with radiotherapy alone with a curative intent. The series was designed to be a matched cohort of 17 patients with local recurrences matched with 17 local cures. There were no significant differences between groups with and without local recurrence in age, gender, subsite, T-stage or treatment year.

Dataset Information

PC4-mediated Ku PARylation facilitates NHEJ-dependent DNA damage repair

Publications

PC4-mediated Ku complex PARylation facilitates NHEJ-dependent DNA damage repair.

Similar Datasets

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