The Expression Of PUMA On Colon Carcinoma Tissues And Its Effect Of Inducing Colon Carcinoma Cells To Apoptosis

Object PUMA(p53 up-regulated modulator of apoptosis) is a BH3-only member of the Bcl-2 family which has owned powerful effect to prmeote apoptosis; it can induce apoptosis by p53-dependent and p53-independent pathway. The object of this experiment was to research the expression of PUMA on colon carcinoma and normal tissues by immunohistochemistry, and to investigate the clinical significance. Induced two colon carcinoma cell lines to apoptosis by 5-Fu, then compare the apoptosis levels of difference time and the expression of PUMA mRNA to investigate the apoptosis effect of PUMA and the basic way by which it can be induced.Method 72 samples of colon carcinoma and 30 samples of carcinoma besides normal tissues has been choosen, and measured by immunohistochemistry to research the expression of PUMA, then the relationship of expression and age, sex, clinic stages, tumor differentiate level, tumor position, chemotherapy, lymphaden metastasis can be analyzed. Furthmore, PUMA mRNA expression was detected by RT-polymerase chain reaction in HCT116 contained wt p53 and HT-29 cells contained mut p53 genes after using the DNA-damaging agent 5-Fu on different time, and apoptosis levels were detected by acridine orange/ethidium bromide double staining(AO/EB) method.Result PUMA expreseed in 26 of 72(36.11％) of colon carcinoma tissues, and 8 of 30(26.67％) of carcinoma besides normal tissues(P＞0.05); The expression in 17 of 32(53.12％) of proximal colon carcinoma and 9 of 40(22.50％) of distal colon carcinoma(P＜0.05), but the expression not related to the age, sex, clinic stage, differentiation level and lymphaden metastasis(P＞0.05). 6 hours after using the 5-Fu, PUMA mRNA expression was found to be induced in HCT116 cell following treatment with 5-Fu and enhanced apparently during the drug action time. Furthermore, the PUMA mRNA expression directly correlated with the cell apoptosis levels. No expression of the mRNA of PUMA was found to be induced in HT-29 within the 48 hours after treated by 5-Fu.Conlcusion 1. There are no significances statistics during the positive rate and expressing level of PUMA and the carcinoma besides normal tissues, but the expressing level of PUMA is higher in proximal colon carcinoma and chemotherapy groups, it is not relate to the age, sex, clinic stage, differentiation level and lymphaden metastasis. 2. The expression of PUMA is reduced totally by p53-pathway during the apoptosis following 5-Fu treatment in colon carcinoma cells, and dependent on intact p53.3. Puma would promote apoptosis in the early time and is likely to play a role in mediating cell death.