The Escherichia coli AlkB protein is a 2-oxoglutarate/Fe(II)-dependent demethylase that repairs alkylated single stranded and double stranded DNA. Immunoaffinity chromatography coupled with mass spectrometry identified RecA, a key factor in homologous recombination, as an AlkB-associated protein. The interaction between AlkB and RecA was validated by yeast two-hybrid assay; size-exclusion chromatography and standard pull down experiment and was shown to be direct and mediated by the N-terminal domain of RecA. RecA binding results AlkB-RecA heterodimer formation and RecA-AlkB repairs alkylated DNA with higher efficiency than AlkB alone.
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http://dx.doi.org/10.1093/nar/gkw611 | DOI Listing |
J Biochem
January 2025
Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
SN1-type alkylating reagents generate O6-methylguanine (meG) lesions that activate the mismatch repair (MMR) response. Since post-replicative MMR specifically targets the nascent strand, meG on the template strand is refractory to rectification by MMR and, therefore, can induce non-productive MMR reactions. The cycling of futile MMR attempts is proposed to cause DNA double-strand breaks in the subsequent S phase, leading to ATR-checkpoint-mediated G2 arrest and apoptosis.
View Article and Find Full Text PDFClin Epigenetics
January 2025
Center of Oncocytogenomics, Institute of Medical Biochemistry and Laboratory Diagnostics, General University Hospital and 1st Faculty of Medicine of Charles University in Prague, U Nemocnice 499/2, 128 00, Prague, Czech Republic.
Background: Glioblastoma is the commonest malignant brain tumor and has a very poor prognosis. Reduced expression of the MGMT gene (10q26.3), influenced primarily by the methylation of two differentially methylated regions (DMR1 and DMR2), is associated with a good response to temozolomide treatment.
View Article and Find Full Text PDFInt J Gynecol Cancer
January 2025
Helsinki University Hospital and University of Helsinki, Department of Obstetrics and Gynecology, Helsinki, Finland; University of Helsinki, Faculty of Medicine, Helsinki University Hospital and Research Program in Applied Tumor Genomics, Department of Pathology, Helsinki, Finland.
Objective: Endometrial carcinomas with mismatch repair deficiency (MMRd) and no specific molecular profile (NSMP) are considered to have intermediate prognoses. However, potential prognostic differences between these molecular subgroups remain unclear due to the lack of standardized control for clinicopathologic factors. This study aims to evaluate outcomes of MMRd and NSMP endometrial carcinomas across guideline-based clinicopathologic risk groups.
View Article and Find Full Text PDFJ Cell Mol Med
February 2025
Department of Chemotherapy, Jiangxi Cancer Hospital, Nanchang, Jiangxi, China.
Tumour cells possess a multitude of chemoresistance mechanisms, which could plausibly contribute to the ineffectiveness of chemotherapy. O-methylguanine-DNA methyltransferase (MGMT) is an important effector protein associated with Temozolomide (TMZ) resistance in various tumours. To some extent, the expression level of MGMT determines the sensitivity of cells to TMZ, but the mechanism of its expression regulation has not been fully elucidated.
View Article and Find Full Text PDFCell Prolif
January 2025
Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
Due to the lack of effective therapeutic approach, glioblastoma (GBM) remains one of the most malignant brain tumour. By in vitro investigations on primary GBM stem cells, we highlighted one of the underlying mechanisms of drug resistance to alkylating agents, the DNA damage responses. Here, flow cytometric analysis and viability and repopulation assays were used to assess the long-term cytotoxic effect induced by the administration of a fourth-generation platinum prodrug, the (OC-6-44)-acetatodiamminedichlorido(2-(2-propynyl)octanoato) platinum(IV) named Pt(IV)Ac-POA, in comparison to the most widely used Cisplatin.
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