title: Regulation of cisplatin resistance and homologous recombinational repair by the TFIIH subunit XPD.
abstract: We have recently completed screening of the National Cancer Institute human tumor cell line panel and demonstrated that among four nucleotide excision repair proteins (XPA, XPB, XPD, and ERCC1), only the TFIIH subunit XPD endogenous protein levels correlate with alkylating agent drug resistance. In the present study, we extended this work by investigating the biological consequences of XPD overexpression in the human glioma cell line SK-MG-4. Our results indicate that XPD overexpression in SK-MG-4 cells leads to cisplatin resistance without affecting the nucleotide excision repair activity or UV light sensitivity of the cell. In contrast, in SK-MG-4 cells treated with cisplatin, XPD overexpression leads to increased Rad51-related homologous recombinational repair, increased sister chromatid exchanges, and accelerated interstrand cross-link removal. Moreover, we present biochemical evidence of an XPD-Rad51 protein interaction, which is modulated by DNA damage. To our knowledge, this is the first description of functional cross-talk between XPD and Rad51, which leads to bifunctional alkylating agent drug resistance and accelerated removal of interstrand cross-links.
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D002453:Cell Cycle / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D002945:Cisplatin / Q000494:pharmacology*; D004265:DNA Helicases; D004260:DNA Repair / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D019008:Drug Resistance, Neoplasm; D004720:Endonucleases; D005910:Glioma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008558:Melphalan / Q000494:pharmacology; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D051135:Rad51 Recombinase; D011836:Radiation Tolerance; D016196:S Phase / Q000502:physiology; D012854:Sister Chromatid Exchange / Q000187:drug effects / Q000502:physiology; D051758:Transcription Factor TFIIH; D014157:Transcription Factors; D019473:Transcription Factors, TFII / Q000096:biosynthesis / Q000502:physiology*; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays; D051760:Xeroderma Pigmentosum Group A Protein; D051759:Xeroderma Pigmentosum Group D Protein
chemical_list: D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D011506:Proteins; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C497314:XPA protein, human; D051760:Xeroderma Pigmentosum Group A Protein; C072022:XPBC-ERCC-3 protein; D051758:Transcription Factor TFIIH; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; C071447:ERCC1 protein, human; D004720:Endonucleases; D004265:DNA Helicases; D051759:Xeroderma Pigmentosum Group D Protein; C497292:ERCC2 protein, human; D002945:Cisplatin; D008558:Melphalan