Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01034 (cystatin C)
 3,397 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Racemic anti-benzo[c]phenanthrene-3,4-diol-1,2-epoxide (anti-B[c]PhDE) is a powerful rat mammary carcinogen and is one of the most potent diol-epoxide tumorigens in mouse skin. Activation of ras genes has been proposed to be involved in tumorigenesis by this and related polynuclear aromatic hydrocarbon metabolites. Therefore, we analyzed rat mammary tumors and mouse skin tumors induced by anti-B[c]PhDE for mutations at codons 12, 13 and 61 of the Ki-ras and Ha-ras genes. No Ki-ras mutations were detected in either tumor type. In the rat mammary tumors, no Ha-ras mutations in codons 12 or 13 were observed in 25 tumors analyzed. Only one, a CAA-->CTA mutation, was detected in codon 61, of 42 tumors analyzed. These results indicate that Ki-ras and Ha-ras mutations are not involved in the induction of rat mammary tumors by anti-B[c]PhDE. Mutations in codon 61 of the Ha-ras gene were common, however, in mouse skin tumors induced by this diol-epoxide, being detected in 63% of the tumors analyzed; 90% of these mutations were CAA-->CTA. A dose-dependent difference in the occurrence of the CAA-->CTA mutations was observed; they were present in 75% of the tumors induced by a 100 nmol initiating dose of the diol-epoxide, but in only 34.5% of the tumors induced by a 400 nmol initiating dose. A CAA-->CTA mutation in codon 61 of Ha-ras was also detected in one of four acetone control tumors. In comparison with previous studies of other polynuclear aromatic hydrocarbons and their metabolites, the results suggest that the reactivity with DNA of anti-B[c]PhDE is one factor involved in the induction of A mutations in Ha-ras genes in mouse skin, but further studies are required to evaluate the significance of these mutations in mouse skin tumorigenesis.
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PMID:Contrasting incidence of ras mutations in rat mammary and mouse skin tumors induced by anti-benzo[c]phenanthrene-3,4-diol-1,2-epoxide. 795 41

Treatment of B6C3F1 mice with concentrations of 62.5-625 p.p.m. 1,3-butadiene by inhalation for up to 2 years causes a significantly increased incidence of Harderian gland (HG) neoplasms over untreated controls (Melnick,R., Huff,J., Chou,B.J. and Miller,R.A. Cancer Res., 50, 6592-6599, 1990). Since a specific K-ras mutation (codon 13 GGC-->CGC) had previously been described in lung and liver tumors from 1,3-butadiene-treated B6C3F1 mice, we analyzed 23 adenomas and six adenocarcinomas of the HG from mice exposed to 1,3-butadiene for this mutation and mutations in the H-ras gene. We also examined ras activation in 16 spontaneously occurring HG adenomas and one adenocarcinoma. DNA samples were prepared from paraffin-embedded tissues and analyzed by PCR followed by direct sequencing methods. Only one 1,3-butadiene-induced HG tumor contained the K-ras codon 13 mutation previously detected in lung and liver tumors. However, 16/29 HG tumors from the treated B6C3F1 mice contained H-ras codon 61 mutations. The mutations detected were: 12 CAA-->CGA transitions, two CAA-->CTA and two CAA-->AAA transversions. Eleven of 17 spontaneous HG tumors contained mutations in H-ras codon 61: five CAA-->CGA transitions, two CAA-->CTA transversions and four CAA-->AAA transversions. While the spectrum of ras mutations did not differ between the spontaneously occurring and chemically induced tumors, these data indicate that activation of H-ras contributes to the process of HG tumorigenesis in both groups of these neoplasms.
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PMID:Activation of H-ras is prevalent in 1,3-butadiene-induced and spontaneously occurring murine Harderian gland tumors. 795 23

We designed a pair of primers from the variable regions (V2 and V4) of 16S rRNA gene of Leptospira interrogans, i. e. PI: 5'GGG AAC CTA ATA CTG GAT GG; PII: 5' ACA TAG TTT CAA GTG GAG GC, and amplified the leptospiral DNAs from different genus and species. When denaturing with 55 degrees C, all DNAs of L. interrogans had the same products not only in length but also with Kpn I-digested pattern. The DNA of L. biflexa could be amplified with a c. a. 280 bp-band but not digested by Kpn I, while the DNAs of Leptonema and other control bacteria had no amplification. In addition, the products of L. interrogans spp. could be hybridized with the PCR product of L. interrogans serovar lai strain Lai labelled with 32P, while the product of L. biflexa had no hybridization. It proved that the 16S rRNA gene primers is useful for the classification and detection of leptospires.
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PMID:[PCR amplification of the leptospiral DNAs from different genus and species with the variable sequences of 16S rRNA gene]. 815 Apr 33

The frequency and spectrum of Ha-ras mutations in benzo[a]pyrene (B[a]P)-initiated/12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted CD-1 mouse skin papillomas were characterized by amplifying high molecular weight papilloma DNA using the polymerase chain reaction (PCR) followed by direct DNA sequencing. Analysis of 10 individual B[a]P-initiated early emergence papillomas indicated that 90% contained a Ha-ras mutation. Twenty percent of these papillomas contained a GGA-->GTA transversion in the 12th codon, 50% contained a GGC-->GTC transversion in the 13th codon and 20% contained a CAA-->CTA transversion in the 61st codon. A characteristic of 7,12-dimethylbenz[a]anthracene (DMBA)-initiated papillomas, which contain an A-->T mutation in the 61st codon of Ha-ras, is that they exhibit a constitutive decrease in both protein kinase C (PKC) activity and PKC alpha and beta 2 isozyme levels when compared to epidermis. In the present study we found that total PKC activity, as well as PKC alpha and beta 2 isoforms, were markedly decreased in B[a]P-initiated early emergence papillomas and that this decrease was also accompanied by an altered subcellular distribution of PKC activity. The particulate/cytosolic (P/C) ratio of PKC activity in the epidermis was 0.39, whereas the P/C ratio in the papillomas was 0.77. These results demonstrate that B[a]P-initiated/TPA-promoted papillomas exhibit a high incidence of specific ras mutations and that PKC levels are constitutively decreased in these papillomas, indicating that an activated ras gene is associated with and may contribute to the observed decrease in PKC levels.
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PMID:Characterization of benzo[a]pyrene-initiated mouse skin papillomas for Ha-ras mutations and protein kinase C levels. 824 57

Previous reports from several laboratories have consistently shown that approximately 30% of spontaneous hepatocellular adenomas and 70-80% of spontaneous hepatocellular carcinomas found in aged B6C3F1 [C57BL/6 (liver tumor resistant) x C3H (liver tumor susceptible)] male mice contain one of three missense point mutations in codon 61 of the H-ras oncogene, CAA-->AAA, CGA or CTA. Irrespective of subline, the C3H mouse, the paternal parent strain of the B6C3F1 hybrid, is more susceptible to spontaneous liver tumorigenesis than the B6C3F1 mouse. However, the role of H-ras in the pathogenesis of hepatocellular tumors in C3H mice is less clear, as widely different frequencies of activation of this gene, but by the same point mutations in codon 61, have been reported by various laboratories. The present study was undertaken to characterize H-ras involvement in hepatocellular tumors of aged C3H/He mice from the NCI-Frederick Cancer Research and Development Center Colony (C3H/HeNCr). Oncogene activation was evaluated in 45 C3H/HeNCr hepatocellular tumors by the NIH 3T3 transfection assays, and point mutations in the H-ras oncogene were detected and characterized in DNA fragments amplified by PCR, using dot blot hybridization analysis with mutation-specific oligonucleotide probes and direct dideoxy sequencing of PCR products. The only transforming gene detected in these tumors by NIH 3T3 transfection was H-ras. Only 17% (1/6) of spontaneous carcinomas and 8% (3/39) of spontaneous adenomas contained transforming H-ras sequences, each with a point mutation in codon 61. In all four cases with H-ras mutations, mutated sequences comprised a minor fraction of total H-ras gene copies in DNA extracted from primary tumors. H-ras mutations thus appear to have arisen relatively late in the pathogenesis of the neoplasms. For comparison, sections of formalin-fixed, paraffin-embedded hepatocellular tumors that occurred in untreated B6C3F1 hybrid mice sired by C3H/HeNCr males were assayed for the same H-ras mutations by PCR and dot blot hybridization. Nine of 13 such tumors (4/6 carcinomas, 5/7 adenomas) were positive. The overall difference in frequency of H-ras codon 61 mutations in hepatocellular tumors in C3H/HeNCr (4/45) versus B6C3F1 (9/13) was highly significant (P = 0.000035, Fisher's exact test). These data indicate that point mutations in H-ras do not generally play a major or an initiating role in spontaneous hepatocarcinogenesis of inbred C3H/HeNCr mice and contrast with the high rate of ras mutations in liver tumors of the B6C3F1 hybrid.
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PMID:Low frequency of H-ras activation in naturally occurring hepatocellular tumors of C3H/HeNCr mice. 840 22

Rifampin susceptibility of 32 rifampin-resistant and 26 rifampin-susceptible Mycobacterium tuberculosis strains was analyzed by PCR-single-strand conformation polymorphism (SSCP) and DNA sequencing within the 157-bp region of the rpoB gene (Ala500 to Val550). Two false-positive PCR-SSCP results were observed among the susceptible strains due to the silent mutation Gln513 (CAA-->CAG) and the deletion mutation Thr508 and Ser509. Another silent mutation [Leu511 (CTG-->CTA)], combined with the mutation Ser531-->Leu, was observed in a resistant strain. These results suggest that to rule out false-positive PCR-SSCP results, sequencing of the target DNA is required.
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PMID:Mutations in the rpoB gene of Mycobacterium tuberculosis that interfere with PCR-single-strand conformation polymorphism analysis for rifampin susceptibility testing. 900 25

It has been hypothesized that tumor promotion in mouse skin involves clonal expansion of initiated cells with activated c-Harvey (Ha)-ras oncogene to give rise to benign tumors. We have used the two stage mouse skin carcinogenesis model using 7,12-dimethylbenz[a]anthracene (DMBA) as the initiator and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) as the tumor promoter to quantitate the number of mutated c-Ha-ras alleles in mouse epidermal DNA. Epidermal samples were harvested over a 12-week period before the appearance of papillomas. Three 61st codon (i.e. CAA) c-Ha-ras mutations, CTA (T2), CGA (G2) and CAT (T3) were quantitated by newly developed nested PCR/RFLP assays. During TPA promotion the number of T2 mutant copies showed a progressive increase starting at 4 weeks after initiation and the number of T3 mutant alleles showed an increase starting at 6 weeks. By 12 weeks after initiation, TPA-promoted mouse epidermis averaged approximately 8x10(5) T2 mutant alleles per epidermis while the number of T3 mutant alleles averaged 3x10(4) per epidermis. The best-fit lines for the quantitation of mutant alleles derived from DMBA/TPA-treated mice from 4 to 12 weeks after initiation were exponential. These results were consistent with clonal expansion of epidermal cells carrying these mutations during tumor promotion. The slopes of the best-fit lines for the mutant copies indicated a trend in which cells with the T2 mutations had a growth advantage during TPA promotion over cells with the T3 mutation.
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PMID:Quantitation of early clonal expansion of two mutant 61st codon c-Ha-ras alleles in DMBA/TPA treated mouse skin by nested PCR/RFLP. 900 88

The mutagenic thymidine analog bromodeoxyuridine (BrdUrd) may incorrectly incorporate opposite deoxyguanine in DNA, then pair with deoxyadenosine during subsequent replication. It appears to preferentially target the 3'-G of 5'-NGGN-3' sequences in mammalian cells in culture to induce G-->A transitions. Ras genes should therefore be vulnerable to activation by mutation at glycine codons 12 (GGT) and/or 13 (GGC) by misincorporation of BrdUrd. There is limited evidence that BrdUrd may be carcinogenic or co-carcinogenic in rats: three renal mesenchymal tumors, a tumor known to be associated with activating mutations in the c-K-ras-2 oncogene, were reported in 87 rats treated with BrdUrd alone, while N-nitrosomethylurea (NMU) alone or NMU + BrdUrd resulted in incidences of 12/52 and 26/76, respectively, against a zero incidence in untreated rats. We analyzed renal mesenchymal tumors from rats treated with BrdUrd for mutations in K-ras exons 1 and 2 and compared the prevalence and spectrum of mutations with those found in comparable tumors induced with NMU. DNAs from 22 paraffin-embedded renal mesenchymal tumors from rats treated 12-15 months earlier with BrdUrd (three specimens) or NMU (11 specimens) or both agents sequentially (eight specimens) were amplified by PCR. The base sequence of codons 12-13 and 59-63 of K-ras was determined by the dideoxynucleotide method. Sequencing results were confirmed by allele-specific oligonucleotide hybridization. Two of three tumors that appeared in rats given BrdUrd alone contained both a codon 12 GGT-->GAT transition and a codon 61 CAA-->CTA transversion. One tumor induced by NMU alone also showed a codon 12 GGT-->GAT mutation, while only wild type sequence could be demonstrated in the codon 12-13 region in the remaining ten such tumors. Three NMU-induced tumors also showed codon 61 CAA-->CTA mutations, while the remaining tumors had wild type sequence. While the GGT-->GAT transitions identified in tumors from BrdUrd-treated rats are consistent with BrdUrd mutagenesis by misincorporation, the co-occurrence of CAA-->CTA transversions, the overall low prevalence of mutations, and the lack of any difference in mutation spectrum between tumors induced by NMU and those that occurred in BrdUrd-treated rats suggests that in both groups the mutations that did occur did not result from a direct effect of either agent.
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PMID:K-ras codon 12 and 61 point mutations in bromodeoxyuridine- and N-nitrosomethylurea-induced rat renal mesenchymal tumors. 902 Aug 96

Isoprene is the 2-methyl analog of 1,3-butadiene, a genotoxic and carcinogenic compound in rats and mice. Male B6C3F1 mice were exposed to 0, 2200 or 7000 ppm isoprene by inhalation (6 h/day; 5 days/week) for 26 weeks. Following a 26-week recovery period, an increased incidence of Harderian gland (HG) neoplasms was observed at both concentrations. The present study was designed to characterize genetic alterations in the K-ras and H-ras protooncogenes in HG neoplasms. Mutations in K-ras and H-ras were identified by single-strand conformational analysis and direct sequencing of polymerase chain reaction (PCR) amplified DNA, isolated from paraffin-embedded sections of HG neoplasms. A higher frequency of ras mutations, in particular K-ras mutations, was detected in isoprene-induced neoplasms than in 1,3-butadiene-induced or control HG neoplasms. All of the isoprene-induced HG neoplasms exhibited activated K-ras (60%) or H-ras (40%) mutations. In contrast, ras mutations were detected in 69% of HG neoplasms from 1,3-butadiene exposed mice (14% K-ras and 55% H-ras) and in 56% of HG neoplasms obtained from control B6C3F1 mice (8% K-ras and 48% H-ras). The predominant mutations in isoprene-induced HG neoplasms, but not in previously or newly analysed 1,3-butadiene-induced HG neoplasms, consisted of A-->T transversions (CAA-->CTA) at K-ras codon 61 (15/30) and C-->A transversions (CAA-->AAA) at H-ras codon 61 (8/30). Two-thirds of the K-ras CTA mutations were detected in HG neoplasms from the 2200 ppm exposure group while one-third was present in the 7000 ppm group. Isoprene-induced HG neoplasms with K-ras or H-ras mutations had an elevated proliferating cell nuclear antigen (PCNA) index, compared to spontaneous HG neoplasms without ras mutations. The high frequency and specificity of the ras mutation profile suggest that ras protooncogene activation contributes to isoprene-induced HG tumorigenesis.
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PMID:Both K-ras and H-ras protooncogene mutations are associated with Harderian gland tumorigenesis in B6C3F1 mice exposed to isoprene for 26 weeks. 911 Dec 15

Dichloroacetic acid (DCA), a disinfection by-product of chlorination found in drinking water, is a hepatocarcinogenic in the B6C3F1 mouse. Previous studies have shown that DCA does not significantly alter the incidence of Ha-ras codon 61 mutations in male mouse liver carcinomas from that observed in spontaneous tumors (approximately 50% have Ha-ras mutations) but it alters the proportions of mutations that occur in Ha-ras codon 61. Twenty-two tumors were produced in female B6C3F1 mice after treatment with 3.5 g DCA per liter of drinking water over a period of 104 weeks. To detect potential Ha-ras mutations in the liver tumor tissue of female B6C3F1 mice, genomic DNA was isolated from tumors that had been frozen. The polymerase chain reaction (PCR) and single-stranded conformational polymorphism (SSCP) was used to screen tumor DNA for mutations in Ha-ras exon 2. In DNA from liver tumors in female B6C3F1 mice induced by DCA-treatment we found only one mutation in exon 2 among the 22 tumors analyzed (4.5%). Direct-sequencing of exon 2 revealed a CAA to CTA transversion in Ha-ras codon 61. The result of this study indicates that tumor formation in DCA-treated female B6C3F1 mice is, therefore, not associated with a mutationally activated Ha-ras codon 61. This result differs from previous results obtained in male B6C3F1 mice.
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PMID:Dichloroacetic acid reduces Ha-ras codon 61 mutations in liver tumors from female B6C3F1 mice. 927 48


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