Expression of P14ARF, MDM2 and mutant type P53 in skin tissue of coal-burning-type of endemic arseniasis patients / 中国地方病学杂志

Objective To determine the protein expression of P14ARF,MDM2 and mutant type P53 (P53mt) in skin specimens of coal-burning-type of endemic arseniasis patients and to reveal the molecular mechanism of the disease.Methods Sixty skin specimens from 60 endemic arseniasis patients including 35 of skin lesions patients,19 of precancerous lesion and 6 of skin cancer and 9 normal skin specimens from non-cancer patients were studied.Expression of P14~,MDM2 and P53mt was evaluated by immunohistochemistry using corresponding monoclonal antibodies.Results There was significant difference in the positive rates of P14ARF,MDM2 and P53mt among the 4 groups(x2 =9.39,6.21,20.64,all P ＜ 0.05).The positive rates of P14ARF in precancerous lesion and skin cancer specimens were 46.1％ (6/19) and 33.3％ (2/6),respectively,which were significantly lower than that of the normal skin specimens [88.9％(8/9),all P ＜ 0.05].Decreased expression of P14ARF was correlated with the development of dermopathy (P ＜ 0.05).The positive rates of MDM2 and P53mt in skin lesions,precancerous lesion and skin cancer specimens were 54.2％ ( 19/35 ),63.2％ (10/19),66.7％ (4/6) and 25.7％(9/35),73.7％(14/19),83.3％(5/6),respectively,which were significantly higher than those of the control (0,0,all P＜ 0.05).The expression of MDM2 and P53mt increased with the development of dermopathy(all P ＜ 0.05).Conclusions P53mt protein in skin tissue of coal-burning-type of endemic arseniasis patients is over expressed.Abnormal expression of P14ARF and MDM2 may be one of the reasons lead to abnormal cell cycle control disorders and may play a role in the development of endemic arseniasis.

Relationship between the methylation and mutation of p53 gene and endemic arsenism caused by coal-burning / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the influence of arsenic pollution caused by coal-burning on methylation (promoter and exon 5) and mutation (exon 5) of human p53 gene, and to analyze the relationship between methylation, mutation and arsenism.</p><p><b>METHODS</b>According to the diagnostic criteria of endemic arsenism, 112 patients with arsenism (including 38 mild cases, 43 moderate cases and 31 severe cases) were selected in the areas with endemic arsenism from Xingren, Guizhou province. Among the subjects, 43 cases were diagnosed by dermatopathological methods, and they were divided into non-cancerous group (24 cases) and cancerous group (19 cases). 90 controls were selected from the non-arsenic polluted areas. Under the principle of informed consent, blood samples were collected from individuals. The methylation of p53 gene in promoter region and exon 5 were detected by extinction enzyme-PCR, the mutation of p53 gene (exon 5) was detected by PCR-SSCP, PCR products cloning and sequencing technology.</p><p><b>RESULTS</b>The positive rates of methylation of p53 gene in promoter region were 13.16% (5/38), 27.91% (12/43) and 45.16% (14/31) respectively among mild, moderate and severe arsenism group, which were obviously higher than the rates in the control group (1.11% (1/90), χ² values were 8.679, 23.690, 41.199, respectively, both P values < 0.017). The positive rates of methylation of p53 gene were 25.00% (6/24) and 63.16% (12/19) in non-cancerous and cancerous group respectively, which were obviously higher than those in the control group (1.11% (1/90), χ² values were 18.762, 57.497, respectively, both P values < 0.025). The positive rates of methylation of p53 gene (exon 5) were 55.26% (21/38), 51.16% (22/43) and 48.39% (15/31) respectively among mild, moderate and severe arsenism group, which were obviously lower than the rates in the control group (88.88% (80/90), χ² values were 18.151, 23.168, 22.420, respectively, both P values < 0.017). The positive rates of methylation of p53 gene (exon 5) were 54.17% (13/24) and 42.11% (8/19) in non-cancerous and cancerous group respectively, which were obviously lower than those in the control group (88.88% (80/90), χ² values were 15.201, 22.075, respectively, both P values < 0.025). The mutation rates of p53 gene (exon 5) were respectively 5.26% (2/38), 16.28% (7/43) and 25.81% (8/31) among mild, moderate and severe arsenism group; while the results in moderate and severe arsenism group were obviously higher than in the control group (0.00%, χ² values were 15.465, 24.870, respectively, both P values < 0.017). The positive rate of mutation of p53 gene (exon 5) were respectively 16.67% (4/24) and 31.58% (6/19) in non-cancerous and cancerous group, which were obviously higher than it in the control group (0.00%, χ² values were 15.545, 30.077, both P values < 0.025). The hypermethylation of p53 gene in promoter region was related with the mutation of p53 gene (exon 5) (coefficient of association was 0.294, P value < 0.05); and the hypomethylation of p53 gene (exon 5) was related with the its mutation (coefficient of association was 0.410, P value < 0.05).</p><p><b>CONCLUSION</b>Arsenic pollution caused by coal-burning can cause the hypermethylation of p53 gene in promoter region, hypomethylation and mutation of p53 gene (exon 5), and the changes of methylation of p53 gene are related with its mutation and might be one of the important etiological factors of arsenic pathogenicity or carcinogenesis.</p>

Cytolytic Activity Analysis of Grass Carp Perforin C-terminal Peptide / 中国生物工程杂志

The cytolytic effect of perforin is a mechanism of anti-virus,killing microbial-infected cells and tumor cells.Perforin is a very important non-specific immune factors in fish.In order to understand the function of perforin,the cDNA of grass carp perforin C-terminal peptide was amplified from grass carp liver and kidney cDNA library.It contains a protein kinase C conserved region 2(C2).The cDNA was connected with pET32a,and transformed to expression bacteria DE3.PFP-C was expressed by a prokaryotic expression system and then purified by affinity chromatography.It showed a significant haemolytic activity when tested with rabbit red cells,the optimal pH for haemolytic activity was 7.5,and its haemolytic function dependents on Ca2+ apparently.