Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human hereditary diseases such as xeroderma pigmentosum, Fanconi's anemia, ataxia telangiectasia, and Bloom's syndrome are characterized by a proneness for developing cancer associated with abnormalities in the processing of DNA damage. The molecular defects responsible for predisposing human tissues to cancer are still not well understood, despite the fact that a considerable amount of work has already been done on this problem. In this paper, we show that in human tumor cell lines, in cells transformed by DNA tumor viruses, and in cells derived from certain cancer-prone disorders, the level of activity of a 42-kDa deoxyribonuclease is many times higher than in diploid untransformed control cells. This suggests that this activity is linked to, or may play a role in, malignant transformation.
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PMID:Enhanced deoxyribonuclease activity in human transformed cells and in Bloom's syndrome cells. 280 19

An enzymatic method is described for disaggregation of viable tumor cells from human solid tumors. The enzymatic cocktail consists of 0.1% collagenase, 0.01% hyaluronidase, and 0.002% deoxyribonuclease. After mechanical mincing of the tumor tissue, tumor specimens are dissociated by incubation in the enzymatic cocktail for 12-18 hours at room temperature. In 17 cases of sarcoma, the mean yield was 5 X 10(6) viable cells per gram tumor tissue. Yield was 1 X 10(7) viable cells per gram tumor tissue in 23 cases of gastrointestinal carcinoma. The viabilities of tumor cell suspensions ranged from 50 to 98%, except for low viabilities in four specimens that were grossly composed almost entirely of necrotic tissue. The dissociation procedure is simple and the viable cell yield is sufficient for applications in studies of human cancer immunobiology.
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PMID:An enzymatic method for the consistent production of monodispersed viable cell suspensions from human solid tumors. 298 62

A deoxyribonuclease activity has been identified in the nuclei of the human cervical carcinoma HeLa. This activity has the novel property of existing as a single strand specific endo- and exodeoxyribonuclease activity. These activities are ionic strength sensitive, with retardation of activity occurring at 50 mM NaCl and above, with the Mn++ ion preferred over the Mg++ ion as activating cation. This activity extensively damages DNA via its single strand nicking and gaping activity. The method used to solubilize this activity as well as the enzyme's characteristics are discussed.
Cancer Biochem Biophys 1986 Jul
PMID:Identification of a deoxyribonuclease activity in the nuclei of the cervical carcinoma HeLa. 301 42

Co-culture of cancer patients' nonadherent peripheral blood lymphocytes with irradiated autologous fresh tumor cells, termed the mixed lymphocyte-tumor interaction (MLTI) test, resulted in significant stimulation of 3H-Tdr in corporation on day 6 in 19 of 37 autologous combinations. The MLTI test was performed in a microtiter wells (0.2 ml) and a variety of solid tumor cells (sarcomas and carcinomas) were used. Tumor cells were dissociated from the fresh biopsy tissue by nontrypsin enzymatic digestion (deoxyribonuclease, hyaluronidase, and collagenase) and the tumor cells enriched by depletion of macrophages using adherence procedures. Occasionally, further tumor cell purification was achieved by separation of cells on the basis of size on dis-continuous gradients. Positive MLTI resulted in stimulation as high as 20-fold over the backgrounds of PBL and tumor cells cultured alone. Mean positive MLTI was SI of 7.7. The negative MLTI were not a reflection of generalized immunosuppression, because tumor cell preparations that did not stimulate autologous PBL did stimulate allogeneic PBL. In an additional patient, PBL not responding in the autologous MLTI did respond to allogeneic tumors. MLTI using cryopreserved cells reproduced the MLTI results using fresh cells in 11 of 16 tests; the other five tests were all positive in the fresh MLTI and negative when using cryopreserved cells. Despite reports from many other groups it appears that positive MLTI were not tumor-specific. In 14 experiments we were able to simultaneously test the proliferative response to autologous tumor as well as to an autologous normal tissue (lung, liver, colon, and bowel). In eight of these experiments positive responses were obtained with tumor stimulators and in seven of these, positive proliferation was also obtained with normal tissue.
Cancer Immunol Immunother 1984
PMID:The human mixed lymphocyte-tumor cell interaction test. I. Positive autologous lymphocyte proliferative responses can be stimulated by tumor cells as well as by cells from normal tissues. 620 46

The disposition of 4'-epi-[14-14C]doxorubicinHCl (4'-epi-[14C]DXR) and [14-14C]doxorubicinHCl [( 14C]DXR) was studied in male Sprague-Dawley rats given 1 mg/kg body weight IV. Most of the radioactivity administered was recovered in the faeces (two-thirds of the dose within 6 days after administration), urine accounting for 15% of the 14C given during the same period. A significant amount of radioactivity was also found in expired air. Significantly higher levels of radioactivity were recorded in the plasma (40 min and 4 h) and liver (40 min) in [14C]DXR-treated animals, whereas in animals treated with 4'-epi-[14C]DXR a higher specific radioactivity was found in the kidneys (40 min and 4 h) and bone marrow (40 min). The total tissue residual radioactivity was greater (P less than 0.05) at 24 h for [14C]DXR (45.8%) than for 4'-epi-[14C]DXR (38.6%). The main radioactive species in urines were the unchanged drugs. Minor metabolites were represented by a polar fraction, 13-dihydroderivatives, and aglycones. Whereas aglycones represent an important fraction of extractable tissue radioactivity in liver samples of many of the treated animals, the unchanged drug was invariably the major radioactive component in spleen, lung, and kidney. Liver extraction studies showed the presence of significant amounts of bound radioactivity that could be recovered in soluble form only after incubation with deoxyribonuclease. The main radioactive species present in the bile were the unchanged drug and a polar fraction. The amount of the former was higher in [14C]DXR-treated than in 4'-epi-[14C]DXR-treated animals. On the other hand, partial glucuronidation of 4'-epi-[14C]DXR was deduced on the basis of results of enzymic hydrolysis of bile samples.
Cancer Chemother Pharmacol 1984
PMID:Disposition of 14C-labelled 4'-epidoxorubicin and doxorubicin in the rat. A comparative study. 658 34

Early detection of testicular leukaemia and the identification of residual leukaemic cells in treated patients are important aims in the management of males with acute lymphoblastic leukaemia (ALL). In most cases of ALL ( greater than 95%) the blast cells express terminal deoxynucleotidyl transferase (TdT), a nuclear enzyme. We have therefore standardized the immuno-fluorescence and -peroxidase techniques (using anti-Tdt antibodies) for identifying TdT cells in the normal thymus, as well as in samples of testis with heavy leukaemic infiltrates (positive controls). TdT cells can be identified in formalin (but not in Bouin's or Carnoy's) fixed paraffin-embedded tissues, and the preservation of morphological details is excellent. The method is nevertheless difficult to standardize and also requires the use of deoxyribonuclease (DNase) for the digestion of sections. However, in frozen tissue sections, stronger staining of TdT cells was found, even without DNase treatment. Good morphology was preserved when cut sections were fixed immediately in the cryostat. In the second part of the study 15 samples from treated boys were analysed to see whether the technique is suitable to identify residual minimal leukaemic infiltrates. In 5 patients scanty disseminated TdT cells were detected, and in 2 patients small clumps of TdT cells were seen. The results indicate that the immunohistological identification of TdT ALL blasts may be the method of choice.
Br J Cancer 1982 May
PMID:Nuclear terminal deoxynucleotidyl transferase in leukaemic infiltrates of testicular tissue. 704 2

Nickel compounds are carcinogenic to humans and experimental animals. However, the mechanisms leading to tumor formation are still not understood since the mutagenic potential is rather weak. In contrast, nickel(II) enhances the cytotoxicity and genotoxicity in combination with several other DNA-damaging agents. To elucidate possible interactions with DNA repair processes, the effect of nickel(II) on the nucleotide excision repair pathway has been investigated after UV irradiation in HeLa cells. Nickel(II) blocks the removal of cyclobutane pyrimidine dimers as determined by T4 endonuclease V-sensitive sites. When the alkaline unwinding technique was applied, significantly less transient DNA strand breaks after UV irradiation were detected in the presence of nickel(II) compared to UV alone, suggesting an inhibition of the incision step of nucleotide excision repair. Once incisions are made, the ligation of repair patches is delayed as well in nickel-treated cells, as observed by the alkaline unwinding and nucleoid sedimentation techniques. This inhibition of DNA repair is partly reversible by the addition of magnesium(II), indicating that the competition between Ni2+ and Mg2+ may provide an important mechanism for the disturbance of DNA-protein interactions involved in the repair process. Since the repair inhibition is observed at noncytotoxic concentrations of nickel(II), it may well be relevant for its carcinogenic action.
Cancer Res 1994 Aug 01
PMID:Nickel(II) interferes with the incision step in nucleotide excision repair in mammalian cells. 803 35

This study describes the induction and repair of UV-induced cyclobutane pyrimidine dimers (CPD) in transcriptionally active and inactive genes in the epidermis of the hairless mouse. Mice were exposed to a single dose of 2000 J/m2 ultraviolet B and kept in darkness for up to 24 h. The CPD frequency was measured in the transcriptionally active hypoxanthine-guanine phosphoribosyltransferase gene, the adenosine deaminase gene, the inactive c-mos protooncogene, and the haptoglobin gene using the CPD-specific enzyme T4 endonuclease V. Sixty % of the CPD was removed from the active genes during the first 4 h, after which no further repair took place up to 24 h. In contrast, the inactive genes did not show any removal of CPD. Assuming that the rate of repair in the c-mos and haptoglobin genes is representative for the repair rate in the genome overall, these results suggest only marginal repair of UV-induced CPD in the mouse epidermis in vivo. The selective repair of active genes in the epidermis of mice resembles that of rodent cells in culture and shows the biological relevance of repair studies performed with cultured rodent cells in vitro.
Cancer Res 1993 Apr 01
PMID:Ultraviolet-induced cyclobutane pyrimidine dimers are selectively removed from transcriptionally active genes in the epidermis of the hairless mouse. 845 36

Ultraviolet B (UVB) component of the sunlight is the major cause of nonmelanoma skin cancer (NMSC) in humans. UVB is absorbed directly by cellular DNA and produces lesions that may cause mutation(s) in target gene(s) ultimately leading to cancer. Early detection of these lesions, therefore, may help to identify individuals at a high risk to develop NMSC, and devise approaches for the prevention of this common malignancy. Employing mouse skin as a model, we applied a 32P postlabelling method to detect UVB-induced DNA lesions in the epidermis in nanomole quantities. Autoradiography maps showed that epidermal DNA from UVB exposed mice at 24 h contain up to five DNA lesions; the quantitation of these lesions showed that their formation increased in a UVB dose-dependent manner. Treatment of DNA samples with the bacteriophage DNA repair enzyme T4 endonuclease V confirmed that four of these lesions are pyrimidine dimers. While, some of these lesions were repaired 18 h after UVB irradiation, 30% of them persisted even 48 h post-irradiation. Application of a sunscreen containing ethylhexyl-p-methoxycinnamate or chemopreventive agent green tea polyphenols or silymarin to the skin of the mice prior to UVB exposure was found to prevent the formation of pyrimidine dimers.
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PMID:Ultraviolet B radiation-induced DNA lesions in mouse epidermis: an assessment using a novel 32P-postlabelling technique. 895 42

The transcripts of five SRIH receptor subtypes (SSTR1, SSTR2, SSTR3, SSTR4, and SSTR5) were investigated by RT-PCR in epithelial cells (EC) and stromal cells (SC) from primary cultures of five normal human prostates and six prostate cancers. Primary cultures of prostate EC were established in serum-free keratynocyte medium with 5% FCS, epidermal growth factor, and bovine pituitary extract; SC were cultured in MEM with 10% FCS. Total RNA was extracted from EC and SC using a modified guanidine thiocyanate method. RT-PCR was performed after deoxyribonuclease treatment, using SSTR1-, SSTR2-, SSTR3-, SSTR4-, and SSTR5-specific-primers and adding glyceraldehyde-3-phosphate dehydrogenase-specific primers as internal control. A PCR product of the expected size of 334 bp, corresponding to SSTR1, was expressed only in EC from prostate cancer, whereas the expected 461-bp product of SSTR2 was found only in EC from normal prostate. SSTR3 messenger RNA was undetectable in normal and cancer EC, whereas SSTR4 and SSTR5 were present in both cell types. SSTR1, SSTR2, SSTR3, SSTR4, and SSTR5 messenger RNAs were not expressed in SC from both normal and cancer prostates. The RT-PCR method clearly demonstrated SSTRs' expression in the human prostate EC in vitro with differences between normal and tumoral samples. Our results may explain the ineffectiveness of some SSTR2 selective SRIH analogues in the treatment of prostate cancer and suggest that the absence of SSTR2 could represent a growth advantage in prostate cancer.
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PMID:Different expression patterns of somatostatin receptor subtypes in cultured epithelial cells from human normal prostate and prostate cancer. 925 35


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