Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

FHIT (Fragile Histidine Triad) is a human tumor suppressor gene. The Fhit protein is believed to inhibit tumor growth by inducing apoptosis through interaction with diadenosine triphosphate (Ap(3)A). The latter is first sequestered and eventually hydrolyzed by Fhit to ADP and AMP. Thus, the balance between the cellular Ap(3)A level and Fhit enzymatic activity may affect cell death or survival. Increasing the Ap(3)A level, e.g., by inhibition of the enzyme, should prevent apoptosis and thus sustain tumorigenesis. To test if certain carcinogenic transition metals could inhibit the enzymatic activity of Fhit, purified human Fhit protein [30 nM in 1.25 mM poly(vinylpyrrolidone)], expressed in and isolated from E. coli, was incubated at pH 6.8 (50 mM HEPES buffer in 150 mM NaCl) with 120 microM Ap(3)A in the presence of 5 mM Mg(II) (activating cation) and 0-100 microM Ni(II), Cu(II), Zn(II), Cd(II), Co(II), Cr(III), As(III), or As(V). The reaction mixtures were analyzed by HPLC. The results revealed a strong inhibitory potential of Cu(II) [0.4], followed by Ni(II) [3.5] >or= Zn(II) [7.0] >> Cr(III) [73] > Cd(II) [98] >> Co(II) [432] [the numbers in brackets are IC(50) values, microM]. As(III) and As(V) had no effect. As revealed by spectrophotometry, mass spectrometry, and gel electrophoresis, the exceptionally strong inhibition by Cu(II) was associated with Fhit dimerization through formation of a disulfide bond. The other metals and also H(2)O(2) and NO did not cause the dimerization. Thus, the effect of Cu(II) must be due to its reaction with Cys-39 bearing the only thiol group in Fhit monomer. Since Cys-39 is not readily accessible in the Fhit molecule, the reaction is most likely facilitated by conformational changes which follow the coordination of Cu(II) by the surface histidines 35, 94, and/or 96. The observed inhibition of Fhit may be mechanistically involved in metal-mediated toxicity and carcinogenesis.
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PMID:In vitro inhibition of the enzymatic activity of tumor suppressor FHIT gene product by carcinogenic transition metals. 1189 78

Trichloroethylene is an industrial solvent used primarily for vapor degreasing and cold cleaning. It was selected for study because of its industrial use and for potential for human exposure. (An estimated 3.5 million workers are exposed to trichloroethylene.) In an earlier study trichloroethylene (stabilized with epichlorohydrin and 1,2-epoxybutane) administered by gavage caused hepatocellular carcinomas in male and female B6C3F1 mice. Trichloroethylene administration did not increase the incidence of tumors in male or female Osborne-Mendel rats. However, the survival of dosed rats was reduced, thereby compromising the sensitivity of the study to detect a carcinogenic effect. The studies described in this report were conducted to compare the sensitivities of four strains of rats (ACI, August, Marshall, and Osborne-Mendel) to diisopropylamine-stabilized trichloroethylene. The results of the present studies demonstrate that long-term administration of trichloroethylene produces nephrotoxicity in four strains of rats and that the susceptibilities of these strains to the nephrotoxic effects of the chemical are similar. Because of chemically induced toxicity, reduced survival, and incomplete documentation of the experimental data, the studies are considered inadequate for either comparing or assessing trichloroethylene-induced carcinogenesis in these strains of rats. Toxicology and carcinogenesis studies of trichloroethylene (more than 99% pure, stabilized with 8 ppm diisopropylamine) were conducted by administering the chemical in corn oil gavage at doses of 0, 500, or 1,000 mg/kg per day, 5 day per week, for 103 weeks to groups of 50 male and 50 female ACI, August, Marshall, and Osborne-Mendel rats. The doses were selected on the basis of results from 13-week gavage studies in which groups of 10 male and 10 female ACI, August, and Marshall rats received daily doses or trichloroethylene (male: 125-2,000 mg/kg; female: 63-1,000 mg/kg). Doses for Osborne-Mendel rats were selected to conform with doses used in an earlier carcinogenicity study in that strain (TR-2). In the 13-week studies, male ACI and August rats receiving 2,000 mg/kg trichloroethylene and male and female Marshall rats receiving 1,835 mg/kg had final mean body weights 12%-17% lower than those of the vehicle controls. All other dose groups had body weights comparable to those of the vehicle controls. Three male August rats dosed with 2,000 mg/kg died. Histopathologic evaluation of tissues revealed no lesions attributable to trichloroethylene administration in the 13-week studies. This absence of histopathologic findings did not accurately predict the nephrotoxic effects of long-term administration of trichloroethylene to rats. Body Weight and Survival in the Two-Year Studies: In the 2-year studies, all dosed groups exhibited some reduction in mean body weights relative to the vehicle controls. Survival relative to vehicle controls was significantly reduced in 7/16 dosed groups (see page 6 of the Technical Report). Also, the survival of high dose male Marshall rats was reduced by a large number of accidental deaths. Nephrotoxicity, reduced survival, and central nervous system toxicity (characterized by sedation, loss of consciousness, tremors, and convulsions) showed that the doses of trichloroethylene selected for the 2-year studies were too high. Renal Effects in the Two-Year Studies: Trichloroethylene caused tubular cell cytomegaly in 82%-100% of all dosed animals. In addition, trichloroethylene produced toxic nephropathy (which was distinguishable from age-related nephropathy) in 17%-80% of the dosed animals. Cytomegaly, karyomegaly, or toxic nephropathy was not found in untreated or vehicle control animals. Trichloroethylene administration was also associated with increased incidences of renal tubular cell adenomas and adenocarcinomas. The incidences of renal lesions are shown in the following table (see page 7 of Technical Report). Other Pathologic Effects in the Two-Year Studies: An increased incidence of interstitial cell tumors of the testis was observinterstitial cell tumors of the testis was observed in high dose male Marshall rats (untreated control, 16/46; vehicle control, 17/46; low dose, 21/48; high dose, 32/48; P=0.002). The incidences of pheochromocytomas of the adrenal gland were significantly reduced in male ACI, female August, female Marshall, and male and female Osborne-Mendel rats. Genetic Toxicology: Trichloroethylene did not cause mutations in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 with or without metabolic activation. In Chinese hamster ovary cells, trichloroethylene did not induce chromosomal aberrations; the results for sister chromatid exchanges were considered positive. Trichloroethylene was mutagenic to mouse L5178Y lymphoma cells in the presence of rat liver S9. Data Audit: Audits of the experimental data for these 2-year studies of trichloroethylene were conducted by the National Toxicology Program (see Appendix Q of the Technical Report). The results of the audits revealed evidence that the doses of trichloroethylene were too high. In addition, there was insufficient documentation of animal breeding, clinical observations, environmental conditions, and analytical chemistry data. Also, individual animal identification was not always verifiable. Conclusions: Under the conditions of these 2-year gavage studies of trichloroethylene in male and female ACI, August, Marshall, and Osborne-Mendel rats, trichloroethylene administration caused renal tubular cell cytomegaly and toxic nephropathy in both sexes of the four strains. However, these are considered to be inadequate studies of carcinogenic activity because of chemically induced toxicity, reduced survival, and deficiencies in the conduct of the studies. Despite these limitations, tubular cell neoplasms of the kidney were observed in rats exposed to trichloroethylene and interstitial cell neoplasms of the testis were observed in Marshall rats exposed to trichloroethylene. Synonyms: acetylene trichloride; 1-chloro-2,2-dichloroethylene; 1,1-dichloro-2-chloroethylene; ethinyl trichloride; ethylene trichloride; 1,1,2-trichloroethylene; trichloroethene Trade names of formulations: Algylen; Anamenth; Benzinol; Blacosolv; Blancosolv; Cecolene; Chlorilen; Chlorylea; Chorylen; Circosolv; Crawhaspol; Densinfluat; Dow-Tri; Dukeron; Fleck-Flip; Flock Flip; Fluate; Gemalgene; Germalgene; Lanadin; Lethurin; Narcogen; Narkogen; Narkosoid; Nialk; Perma-A-Chlor; Perm-A-Clor; Petzinol; Philex; Threthylen; Threthylene; Trethylene; Tri; Triad; Trial; Triasol; Trichloran; Trichloren; Triclene; Tri-Clene; Trielene; Trielin; Triklone; Trilen; Trilene; Triline; Trimar; Triol; TRI-plus; TRI-plus M; Vestrol; Vitran; Westrosol Target Organs & Incidences from 2-year Studies
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PMID:NTP Toxicology and Carcinogenesis Studies of Trichloroethylene (CAS No. 79-01-6) in Four Strains of Rats (ACI, August, Marshall, Osborne-Mendel) (Gavage Studies). 1274 81

There is limited information on the molecular changes involved in the pathogenesis of gallbladder carcinoma (GBC). The Fragile Histidine Triad (FHIT) gene, encompassing the FRA3B fragile site at chromosome 3p14.2, is a candidate tumor suppressor gene in a variety of human malignancies. Recent studies have suggested that Fhit inactivation can be a consequence of defects in mismatch repair proteins. We analyzed Fhit and Mlh1 protein expressions using immunohistochemical methods in 20 GBCs and three gallbladder adenomas (GBAs) to elucidate the role of Fhit protein in gallbladder carcinogenesis. In addition, we examined whether Fhit and Mlh1 protein expressions correlated with P53 expression and clinicopathological findings. Significant loss or reduction in Fhit expression was noted in nine (45%) of the GBCs and one of the GBAs. Loss of Mlh1 protein expression was detected in six (30%) of the GBCs and one of the GBAs. Reduced Fhit expression was significantly associated with the absence of Mlh1 protein expression in the GBCs and the GBAs (p=0.0186). P53 overexpression was present in 11 (55%) of the GBCs, but none of the GBAs. Fhit and Mlh1 protein expressions were not significantly associated with P53 expression and clinicopathological findings. These results suggested that reduced Fhit expression might be involved in the development of GBC and be correlated with Mlh1 expression.
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PMID:Expression of Fhit, Mlh1, and P53 protein in human gallbladder carcinoma. 1296 85

The Fragile Histadine Triad (FHIT) is a putative tumor suppressor gene involved in different tumors. The objective of this study was to examine the effect of codon 98 of FHIT on cervical carcinogenesis. The study subjects were patients who were pathologically diagnosed with cervical neoplasia and who had a positive result for human papillomavirus (n = 567) compared to normal healthy women as normal controls (n = 506). The FHIT-specific sequences of DNA from peripheral blood samples from study subjects were determined by PCR using allele-specific primers and were compared with those of the controls. The genetic susceptibility of codon 98 of the FHIT gene (3p14.2) in cervical carcinogenesis was determined by examining the effect of the gene and environmental factors vs. the different stages of cervical intraepithelial lesions and the different histopathologic types of invasive cervical cancers. On assessing FHIT polymorphisms, the percentages of individuals homozygous for the T allele, homozygous for the C allele, and heterozygous for these two alleles were 42.1%, 11.3, and 46.6% in the control group. The corresponding figures were 39.5%, 14.8%, and 45.7% among in women with cervical cancer. Compared with FHIT T/ T, odds ratio (95% confidence interval) for FHIT C/C was 1.4 (0.8-2.5) for invasive cervical cancer and 1.7 (0.9-3.1) for cervical intraepithelial neoplasia (CIN) II or III. The risks for invasive cervical cancer were higher with early onset cervical carcinogenesis (2.3, 1.0-5.5, P = 0.0438), than with late onset (1.0, 0.5-2.1, P = 0.9306). The risks of FHIT C/C or C/ T also increased for ever smokers or women with two or more children compared with FHIT T/ T. Polymorphisms of FHIT are associated with a higher risk of developing cervical cancer, in particular early onset cervical carcinogenesis.
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PMID:The effect of codon 98 of the FHIT gene on cervical cancer in Korean women. 1467 22

Human papillomavirus (HPV) is considered to be a major etiological factor but is not sufficient for the development of cervical cancer. Other host factors including altered tumor suppressor gene activities might contribute to the carcinogenic process. Fragile Histidine Triad (FHIT) has been shown to play a pivotal role in carcinogenesis. Therefore, we made an attempt to find out point mutation of FHIT gene in HPV mediated cervical cancer in Indian women. 112 cases of cervical carcinoma tissue biopsies and 38 cervical scrapes samples of normal cytology were employed for this study. Herein, we report a novel mutation identified at nucleotide position 655, at codon 98 from CAT --> CGT with ultimate replacement of amino acid Histidine by Arginine in cervical cancer cases. Molecular modeling was performed to predict the effect of this mutation in disease pathology. We predict that this change, His to Arg substitution in substrate-binding domain may generate catalytically inactive protein with loss of tumor suppressor activity.
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PMID:Novel missense mutation in FHIT gene: interpreting the effect in HPV-mediated cervical cancer in Indian women. 1973 Sep 90

FRA3B and FRA16D are the most sensitive common chromosomal fragile site loci in the human genome and two tumor suppressor genes FHIT (Fragile Histidine Triad) and WWOX (WW domain-containing oxidoreductase gene) map to this sites. The WWOX gene is composed of 9 exons and encodes a 46-kD protein that contains 414 amino acids. Loss of heterozygosity, homozygous deletions, and chromosomal translocations affecting WWOX has been reported in several types of cancer, including ovarian, esophageal, lung and stomach carcinoma, and multiple myeloma. The aim of this study was to determine the role of WWOX as a tumor suppressor gene in patients with breast cancer. Tumor and adjacent non-cancerous tissue samples were obtained from 81 patients with breast cancer. DNA was isolated from all tissue samples, and all exons and flanking intronic sequences of the WWOX gene were analyzed by PCR amplification and direct sequencing. We detected 14 different alterations in the coding sequence and one base substitution at the intron 6 splice site (+1 G-A). In addition to exonic and splice-site alterations, we detected 23 different alterations in the non-coding region of the gene. All coding region mutations identified in this study were in the exons between 4 and 9. We did not observe any alterations in exons 1-3. We conclude that mutations in critical region of the WWOX gene are frequent and may have an important role in breast carcinogenesis.
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PMID:Genetic alterations of the WWOX gene in breast cancer. 2198 61