Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043346 (xeroderma pigmentosum)
 2,924 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neocarzinostatin (NCS) induces repair in a xeroderma pigmentosum lymphoblastoid line deficient in the ability to repair DNA damage induced with (acetoxyacetyl-amino)fluorene. Repair was demonstrated by the induction of repair synthesis and by the disappearance of NCS-induced single-strand breaks and/or alkaline-labile sites in DNA. Estimation of NCS-induced repair patch size, based on the density shift induced in DNA by extensive shear after incubation of treated cells in medium with bromodeoxyuridine or by calculation from the extent of restoration of DNA sedimentation profiles in alkaline sucrose gradients and the amount of repair synthesis measured by the BND cellulose method, indicated that only a few nucleotides were inserted per repaired region. NCS-treated bacteriophage T7 DNA requires incubation with alkaline phosphatase to make it a substrate for DNA polymerase I. NCS-reacted T7 DNA, even after phosphatase treatment, is not a substrate for a DNA polymerase alpha obtained from human lymphoma cells. NCS-treated T7 DNA did serve as a substrate for the DNA polymerase alpha when incubated with an apurinic/apyrimidinic (AP) endonuclease with associated 5'-3'-exonuclease activity. The results suggest that NCS-induced AP sites could be intermediates for the in vivo repair synthesis.
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PMID:Repair of neocarzinostatin-induced deoxyribonucleic acid damage in human lymphoblastoid cells: possible involvement of apurinic/apyrimidinic sites as intermediates. 625 59

2 mutant mouse cells M10 and Q31 were examined for chromosomal aberrations induced by ultraviolet radiation (UV) and 4-nitroquinoline-1-oxide (4NQO), as compared with mouse lymphoma L5178Y cells. Q31 cells are UV- and 4NQO-sensitive cells isolated from L5178Y cells. M10 cells are similar but are sensitive to ionizing radiation and 4NQO. After treatment with UV or 4NQO, chromatid-type aberrations in these cell strains were induced more frequently in the first mitotic cells, at late fixation times. After UV exposure (2.4 J/m2), the maximal frequencies of chromatid-type breaks in Q31 cells were about 5 times higher than in L5178Y cells. In M10 cells such breaks were only as frequent as in L5178Y cells. After 4NQO treatment (50 ng/ml) the frequencies of chromatid-type breaks in M10 and Q31 cells were significantly higher than in L5178Y cells. From these results and those of previous studies (Takahashi et al., 1982), M10 cells may be considered hypersensitive to gamma-rays and 4NQO, but not to UV, and thus react similarly to L5178Y cells. The hypersensitivity of M10 cells to 4NQO may result from a defect in the ionizing-radiation repair mechanism as has been suggested to occur in ataxia telangiectasia (AT) cells. Q31 cells are hypersensitive to UV and 4NQO, but not to gamma-rays. Q31 cells may be considered to be deficient in a UV-like repair pathway. In conclusion, characteristics of murine M10 and Q31 cells are compared with those of human AT and xeroderma pigmentosum (XP) cells.
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PMID:Chromosomal hypersensitivity in mutant M10 and Q31 mouse cells exposed to ultraviolet radiation (UV) and 4-nitroquinoline-1-oxide (4NQO). 640 61

The potential of enhanced chromatid damage, observed after X-irradiation of G2 phase, has been used to detect individuals genetically predisposed to cancer, utilising fibroblast/lymphocytes from these patients as well as fibroblasts derived from human tumours. Fibroblasts and/or lymphocyte samples of two autosomal recessive syndromes (xeroderma pigmentosum (XP), Fanconi's anaemia (FA)) and one congenital or acquired disorder, aplastic anaemia (AA), were employed for the G2 radiosensitivity assay. In addition, we have estimated the frequencies of spontaneously occurring chromosomal aberrations as well as G2 radiosensitivity of eight samples of fibroblasts/fibroblast-like cells (two normal, two colorectal carcinoma, two Wilms' tumour, one retinoblastoma and one polyposis coli), and three samples of lymphocytes (two normal and one from a lymphoma patient). The results obtained indicate that there were no differences between fibroblast cells derived from patients or tumours, except FA patients, in the frequency of spontaneously occurring chromosomal aberrations when compared to normal cells. Following X-irradiation we did not observe any significantly increased G2 radiosensitivity in FA and XP cells. Lymphocytes from AA and lymphoma patients, and all tumour cell lines except retinoblastoma, responded with increased frequencies of aberrations following G2 X-irradiation in comparison to cells derived from normal individuals. In our hands, the G2 sensitivity assay could not always discriminate cells from cancer-prone individuals from those of controls.
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PMID:G2 radiosensitivity of cells derived from cancer-prone individuals. 789 7

Halothane (CAS 151-67-7) induced DNA strand breaks in isolated lymphocytes of two patients with a deficient DNA repair (xeroderma pigmentosum). In lymphocytes (resting cells) of healthy human donors and in L 5178 Y cells (proliferating cells) of mouse lymphoma, halothane did not induce demonstrable DNA strand breaks. The cells were exposed to 1.0 vol/% halothane for 60 min, and the DNA strand breaks were demonstrated by alkaline elution. The results suggest a possible genotoxic side effect of halothane in patients with deficiency in DNA repair.
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PMID:DNA strand breaks in cells with DNA repair deficiency after halothane exposure in vitro. 849 71

We demonstrated previously that the nucleoside of fludarabine (F-ara-A), a clinically effective agent against chronic lymphocytic leukemia and low-grade lymphoma, produces synergistic cytotoxicity against cisplatin-resistant CP2.0 human colon tumor cells when administered in combination with cisplatin. The purpose of this study was 2-fold: (i) to determine whether the synergy occurs in K562 human chronic myelogenous leukemia cells, which, unlike CP2.0 cells, are relatively resistant to drug-induced apoptosis because they express P210(bcr-abl) and (ii) to study the underlying mechanism for the synergy if the enhancement of cytotoxicity occurs in K562 cells. When K562 cells were treated with fludarabine nucleoside and cisplatin as single agents for 4 hr, IC50 values for fludarabine and cisplatin were 3.33 and 2.28 microM, respectively, as measured by a clonogenic survival assay. The simultaneous treatment of K562 cells with the two agents resulted in synergistic cell killing as determined by median-effect analysis. Such synergistic cell killing by combined cisplatin and fludarabine could not be detected in repair-deficient human xeroderma pigmentosum cell lines. Within the range of cytotoxic concentrations, fludarabine (2.5-15 microM) and cisplatin (3-30 microM) as single agents produced no detectable internucleosomal DNA fragmentation as revealed by gel electrophoresis, nor did the combination of the two drugs induce apoptotic DNA degradation. The effects of fludarabine on the repair of cisplatin-induced DNA adducts and interstrand cross-links in K562 cells were analyzed to determine their correlation with the cytotoxic synergy. The interstrand cross-links were measured by the ethidium bromide binding fluorescence assay and quantitative Southern blotting technique. Repair of the intrastrand adducts was detected with whole-cell extracts using a cisplatin-damaged plasmid as the substrate for the in vitro repair assay. Fludarabine at clinically achievable concentrations (1.5-4.5 microM fludarabine nucleoside; 20-100 microM fludarabine triphosphate) inhibited the repair of the DNA lesions induced by cisplatin in a dose-dependent fashion in K562 cells but not in xeroderma pigmentosum cells. Cotreatment with fludarabine preferentially increased the number of interstrand cross-links induced by cisplatin in actively transcribed genes in K562 cells. These data demonstrate the DNA-repair-inhibitory effect of fludarabine and suggest that this effect may contribute to the synergistic cytotoxicity of the fludarabine/cisplatin combination that resulted in decreased clonogenic survival of apoptosis-resistant K562 cells.
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PMID:Fludarabine-mediated repair inhibition of cisplatin-induced DNA lesions in human chronic myelogenous leukemia-blast crisis K562 cells: induction of synergistic cytotoxicity independent of reversal of apoptosis resistance. 935 70

Xeroderma pigmentosum is an inheritable autosomal recessive DNA repair deficient syndrome characterized by a high predisposition to skin cancers. An elevated proportion of tumors from xeroderma pigmentosum patients harbor ultraviolet-induced mutations (CC:GG > TT:AA tandem transitions) of the p53 and/or the INK4a-ARF genes. Here, we report the clinical and molecular features of a 12 y old xeroderma pigmentosum patient who, in addition to severe cutaneous clinical symptoms, also had three unusual tumors, a mediastinal lymphoblastic lymphoma, an atypical fibroxanthoma, and an epithelioid hemangioma. Single strand conformation polymorphism and sequencing analysis of the p53 and INK4a-ARF genes were carried out in DNA from normal skin and different tumors (four actinic keratosis, two microinvasive squamous cell carcinomas, one basal cell carcinoma, and one atypical fibroxanthoma) from the patient. After characterization of the xeroderma pigmentosum C complementation group, we found unexpectedly that this patient also carried a germline mutation of the INK4a-ARF locus affecting the p16INK4A reading frame. Three different somatic mutations that all harbor the signature of ultraviolet light (two of p16INK4A and one of p53) were also detected in the basal cell carcinoma. We hypothesize that the germline mutation of p16INK4A, in association with the nucleotide excision repair defect, could explain the patient's unusual phenotype. Furthermore, this study confirms that concomitant somatic mutations of INK4a-ARF and p53 occur in some xeroderma pigmentosum associated tumors, and seem to accumulate during tumor progression rather than the initiation step.
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PMID:Germline and somatic mutations of the INK4a-ARF gene in a xeroderma pigmentosum group C patient. 1248 39

Infection with immunosuppressive lentiviruses is associated with increased cancer risk,but most studies have implicated indirect mechanisms as the tumor cells generally lack integrated viral sequences. An exception wasfound in a B-cell lymphoma (Q254) where the tumor cells contained a single integrated feline immunodeficiency virus genome. Additional analysis now indicates that feline immunodeficiency virus integration in lymphoma Q254 resulted in promoter insertion and truncation of a conserved gene on feline chromosome B3, whereas the unaffected allele of the gene appeared to be transcriptionally down-regulated. The orthologous human gene (FLJ12973), is expressed ubiquitously and encodes a WD-repeat protein with structural similarity to DDB2, the small subunit of the xeroderma pigmentosum XP-E complex. Moreover, the gene is located within a region of frequent tumor-specific deletions on chromosome 15q15. These observations demonstrate the direct mutagenic potential of the lentiviruses and identify a new candidate tumor suppressor gene.
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PMID:Feline immunodeficiency virus integration in B-cell lymphoma identifies a candidate tumor suppressor gene on human chromosome 15q15. 1249 53

Conjunctival tumors encompass a broad range of diagnoses. The 3 most important malignant tumors include ocular surface squamous neoplasia (OSSN) (14%), melanoma (12%), and lymphoma (7%). Conjunctival malignancies are rarely found in children. Regarding OSSN, pre-disposing conditions include chronic solar radiation, immune deficiency (HIV), organ transplant, autoimmune conditions, xeroderma pigmentosum, and chronic exposure to cigarette smoke. OSSN is managed surgically or with topical/injection immunotherapy or chemotherapy. Metastasis occurs in <1%. Regarding melanoma, predisposing conditions include primary acquired melanosis (PAM), chronic nevus, and chronic solar radiation. Treatment of PAM or nevus can prevent melanoma. Melanoma management involves surgical resection with clean margins and avoidance of direct tumor manipulation ("no touch" technique). The first surgery is most important, to minimize tumor seeding. Biomarkers including BRAF, TERT, and PTEN provide information regarding risk for metastasis and allow for targeted antibiomarker therapies. Ten-year risk for melanoma metastasis is 25%. Tumors >2 mm thickness or those located in fornix, caruncle, or orbit are at highest risk for metastasis. Regarding lymphoma, predisposing conditions include benign reactive lymphoid hyperplasia, immune deficiency (HIV), immune dysfunction, and chronic inflammation/infection (Helicobacter pylori, Chlamydia psittaci). The 4 most important subtypes include extranodal marginal zone lymphoma (ENMZL), follicular lymphoma, mantle cell lymphoma (MCL), and diffuse large B-cell lymphoma. Treatment includes surgical resection, cryotherapy, radiotherapy, systemic chemotherapy, or targeted anti-B-cell therapy (rituximab). Lymphoma-related survival (5-year) depends on subtype and ranges from 97% (ENMZL) to 9% (MCL). Recognizing conjunctival tumors and understanding predisposing factors, biomarkers, and treatment strategies are vital to patient outcomes.
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PMID:Conjunctival Tumors: Review of Clinical Features, Risks, Biomarkers, and Outcomes--The 2017 J. Donald M. Gass Lecture. 2839 47