Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.99.3 (PRE)
 1,923 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DNA photolyase binds to and repairs cyclobutane pyrimidine dimers induced by UV radiation. Here we demonstrate that in the yeast Saccharomyces cerevisiae, photolyase also binds to DNA damaged by the anticancer drugs cis-diamminedichloroplatinum (cis-DDP) and nitrogen mustard (HN2) and by the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Surprisingly, mutations in photolyase were associated with resistance of yeast cells to cis-DDP, MNNG, 4-nitroquinoline oxide (4NQO), and HN2. Transformation of yeast photolyase mutants with the photolyase gene increased sensitivity to these agents. Thus, while the binding of photolyase to DNA damaged by UV radiation aids survival of the cell, binding to DNA damaged by other agents may interfere with cell survival, perhaps by making the lesions inaccessible to the nucleotide excision repair system.
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PMID:A novel role for DNA photolyase: binding to DNA damaged by drugs is associated with enhanced cytotoxicity in Saccharomyces cerevisiae. 796 45

We have analyzed gene-specific and strand-specific DNA damage and repair in the dihydrofolate reductase gene in hamster cells. Cells were UV-irradiated or treated with two types of chemotherapeutics, alkylating agents or cisplatin. UV-induced pyrimidine dimers were detected using a previously published technique in which the T4 endonuclease V enzyme is used to create nicks at the lesion sites. 6-4 photoproducts were detected in a similar assay using ABC excinuclease after prior reversal of the pyrimidine dimers with photolyase. Adducts formed by the alkylating agents nitrogen mustard and dimethyl sulfate were quantitated by generating strand breaks at basic sites after neutral depurination. Cisplatin-induced intrastrand adducts were detected with ABC excinuclease, and cisplatin interstrand cross-links were detected using a denaturation-reannealing reaction before electrophoresis. In accord with previous reports by other investigators, we find distinct strand specificity of the repair of pyrimidine dimers after UV; the transcribed strand was much more efficiently repaired than the nontranscribed strand. In contrast, there was little or no strand bias in the repair of the 6-4 photoproducts. For alkylating agents, a slight bias toward repair in the transcribed strand was found after treatment with nitrogen mustard, but there appeared to be no bias in the repair after treatment with dimethyl sulfate. Cisplatin interstrand cross-links are repaired with equal efficiency from the two strands, but the more common cisplatin-induced lesion, the intrastrand adduct, is preferentially repaired from the transcribed strand. In conclusion, there is strand bias in the repair of pyrimidine dimers and cisplatin intrastrand adducts, but the strand specificity of repair may not be a general feature for all DNA lesions, as we found little or no strand bias in the repair of other lesions studied.
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PMID:Repair of individual DNA strands in the hamster dihydrofolate reductase gene after treatment with ultraviolet light, alkylating agents, and cisplatin. 842 Sep 40

Cisplatin-containing chemotherapy and complete surgical resection are both crucial in the cure of hepatoblastoma. Radical resection can be obtained either conventionally by partial hepatectomy or with orthotopic liver transplant, but the surgical approach to hepatoblastoma differs considerably across the world. Our main aim in this paper is to present the surgical recommendations of the Childhood Liver Tumour Strategy Group of the International Society of Paediatric Oncology (SIOPEL), as well as to stimulate international debate on this issue. We discuss biopsy, verification of resectability, resection principles, indications and potential contraindications for orthotopic liver transplant, as well as thoracic surgery for pulmonary metastases. We suggest that heroic liver resections with a high probability of leaving residual tumour should be avoided whenever possible. In such cases primary orthotopic liver transplant should be considered. Superior survival rates in hepatoblastoma patients who have received a primary transplant after a good response to chemotherapy support the strategy of avoiding partial hepatectomy in cases where radical resection appears difficult and doubtful. We recommend early referral to a transplant surgeon in cases of: (i) multifocal or large solitary PRETEXT IV (PRE Treatment EXTent of disease scoring system) hepatoblastoma involving all four sectors of the liver and (ii) unifocal, centrally located tumours involving main hilar structures or main hepatic veins. Because complete tumour resection is a prerequisite for cure, any strategy leading to an increased resection rate will result in improved survival. We advise the more frequent use of orthotopic liver transplant, as well as the standardisation of techniques for partial liver resection. These guidelines should not be seen as final, but rather as a starting point for further discussion between the various national and international liver tumour study groups.
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PMID:Guidelines for surgical treatment of hepatoblastoma in the modern era--recommendations from the Childhood Liver Tumour Strategy Group of the International Society of Paediatric Oncology (SIOPEL). 1586 52