Summary: P21 WAF1/Cip1 , an inhibitor of cyclin dependent kinases, is a critical downstream effector in the P53 specfic pathway of growth control. Increased expression of P21 WAF1/Cip1 has been found to ref...Summary: P21 WAF1/Cip1 , an inhibitor of cyclin dependent kinases, is a critical downstream effector in the P53 specfic pathway of growth control. Increased expression of P21 WAF1/Cip1 has been found to reflect the status of the P53 tumor suppressor pathway. We investigated the expression of P21 WAF1/Cip1 in a relatively small, but well characterized group consisting of 28 hepatocellular carcinomas. The samples were previously studied for P53 gene mutation. P21 WAF1/Cip1 expression were identified by in situ hybridization and immunohistochemistry. Positive ISH for P21 WAF1/Cip1 transcripts was found in 18 of 28 cases (64.3 %). All positive cases by ISH showed detectable P21 WAF1/Cip1 protein reactivity by IHC. No relationship was found between P21 WAF1/Cip1 staining and P53 mutational status. No associations were seen with tumor metastasis, size and tumor grade, except for tumor differentiation status which showed higher frequency of P21 WAF1/Cip1 expression in moderate well differentiated HCCs than poorly differentiated tumors ( P <0.05). It is concluded that expression of P21 WAF1/Cip1 is common in HCCs, but does not correlate with P53 mutational status or pathological parameters investigated except for tumor differentiation. Also, there may be other factors beside P53 that regulate P21 WAF1/Cip1 gene expression in HCCs.展开更多
Objective To determine the expression of P53 and P21 (WAF1/CIP1) in thyroid carcinomas and its relationship with development and prognosis of the carcinoma. Methods 90 cases of thyroid tissues (60 thyroid carcinomas, ...Objective To determine the expression of P53 and P21 (WAF1/CIP1) in thyroid carcinomas and its relationship with development and prognosis of the carcinoma. Methods 90 cases of thyroid tissues (60 thyroid carcinomas, 10 thyroid adenomas, 10 goitres and 10 normal thyroid tissues) were studied by SP immunohistochemical method. Results Positive immunoreactivity of P53 and P21(WAF1/CIP1) was found only in thyroid carcinomas. The positive rate of the P53 and P21 is 53.3% and 41.7% respectively. The positive-staining rates of P53 were higher in cases of undifferentiated carcinomas, positive metastasis lymph nodes or in stage Ⅲ, Ⅳ than those in the cases of well-differentiated, no metastasis lymph nodes, or in stage Ⅰ,Ⅱ. In addition, the positive-staining of P21(WAF1/CIP1) were lower in cases of undifferentiated carcinomas, positive metastasis lymph nodes or stage Ⅲ, Ⅳ than that in the cases of well-differentiated, no metastasis lymph nodes or in stage Ⅰ,Ⅱ. The P21 (WAF1/CIP1) expression rate in the P53 positive group was lower than that in the P53 negative group (P<0.05). Conclusion The expression of P21(WAF1/CIP1) protein in thyroid cancer is related to P53-depend pathway and P53-independent pathway, mainly the P53-depend pathway. Examination of expression of P53 and P21 (WAF1/ CIP1) proteins may be helpful to judge the thyroid cancer's behavior and prognosis.展开更多
Objective: To investigate the post-transcriptional regulation of p21WAF1/CIP1 by p53. Methods: The MDA-MB-468 cells have endogenous mutant p53 and the MCF7 cells lines have wtp53. Recombinant p53 expression and p21WAF...Objective: To investigate the post-transcriptional regulation of p21WAF1/CIP1 by p53. Methods: The MDA-MB-468 cells have endogenous mutant p53 and the MCF7 cells lines have wtp53. Recombinant p53 expression and p21WAF1/CIP1 induction were detected by Western blot analysis. Northern blot analysis was carried out to examine whether changes in p21WAF1/CIP1 protein levels in MCF7 cells treated with AdCMVp53 are reflected at the mRNA level. Flow cytometric analysis of MCF7 cells following overexpression of recombination. Results: The ratio of p53: p21WAF1/CIP1 was below 1 at the early stages of AdCMVp53 infection, but increased to 1.6 by day 3 and to 9.7 by day 5 post-infection. As expected, p21WAF1/CIP1 expression was not detectable in MDA-MB-468 cells despite the presence of high levels of mutant p53 protein. The G1/S ratios in untreated controls and AdCMVβgal infected MCF7 cells were 1.10 and 1.35, respectively. By Northern blot analyzing the p21WAF1/CIP1: GAPDH ratios at different time points against the ratio at time point 0, a maximum 3-fold induction of p21WAF1/CIP1 mRNA expression relative to untreated control was observed on day 1 post-infection. The flow cytometric analysis indicated that MCF7 cells infected with AdCMVp53 undergo G1 arrest at both time points studied, with G1/S ratios ranging from 5.54 at day 1 to 5.65 at day 7. The G1/S ratios in untreated controls and AdCMVβgal infected MCF7 cells were 1.10 and 1.35, respectively. Conclusion: This study demonstrated that p53 could regulate p21WAF1/CIP1 gene expression at both the transcriptional and post-transcriptional levels in MCF7 cells. The latter mechanism may be involved in or be responsible for, the induction of cell cycle arrest by transcription-defective mutants of p53.展开更多
Background:High-dose ultraviolet (UV) A1 therapy (doses in the order of 130 J cm-2) is effective for atopic dermatitis and scleroderma. UVA1 has been shown to induce a dose-dependent increase in p53 expression in kera...Background:High-dose ultraviolet (UV) A1 therapy (doses in the order of 130 J cm-2) is effective for atopic dermatitis and scleroderma. UVA1 has been shown to induce a dose-dependent increase in p53 expression in keratinocytes. Objectives:To examine the effect of UVA1 on the activation of p53 by phosphorylation, which has not yet been studied. Methods:Five adult volunteers were exposed to dose series of UVA1 (10-100 J cm-2) and, for comparison, narrowband UVB (TL-01) (25-550 mJ cm-2) and solar-simulated radiation (SSR) (5.6-30 J cm-2)on photoprotected buttock skin and the minimal erythema dose (MED) for each was determined at 24 h. Separate sites on the buttock were subsequently irradiated with a 3-MED dose of UVA1, TL-01 and SSR. At 24 h, punch biopsies (4 mm) were taken from each irradiated site and from an adjacent unirradiated control site, and immunohistochemical staining for p53 (Do-1), activation of p53 (assessed by phosphorylation at serine 12 and serine 392) and p21 was performed. Cell staining was expressed as the mean number of cells stained per three high-power fields (HPFs) and as a percentage of 1000 cells. Sunburn cells (SBCs)were also counted per HPF. Results UVA1 produced negligible numbers of SBCs, relatively little p53 (Do-1) staining (mean±.SD cell count per HPF 16±10),no p53 activation and very little evidence of p21 expression (mean±SD cell count per HPF 5.3±7), in contrast to TL-01 (mean±SD cell count per HPF of 11.83±2.1 SBCs, 146.3±38 for Do-1, 26.6±15 for serine 15, 14.9±12 for serine 392 and 77.9±30 for p21) or SSR irradiation (mean±SD cell count per HPF of 3.5±1.2 SBCs, 147.5±62 for Do-1, 54±50 for serine 15, 38.9±18 for serine 392 and 56.7±30 for p21). Conclusions:These data indicate that there are fundamental differences in the effects of UVA1 on p53 and its activation pathways compared with TL-01 and SSR, and may in part explain the differential effects of these phototherapies.展开更多
文摘Summary: P21 WAF1/Cip1 , an inhibitor of cyclin dependent kinases, is a critical downstream effector in the P53 specfic pathway of growth control. Increased expression of P21 WAF1/Cip1 has been found to reflect the status of the P53 tumor suppressor pathway. We investigated the expression of P21 WAF1/Cip1 in a relatively small, but well characterized group consisting of 28 hepatocellular carcinomas. The samples were previously studied for P53 gene mutation. P21 WAF1/Cip1 expression were identified by in situ hybridization and immunohistochemistry. Positive ISH for P21 WAF1/Cip1 transcripts was found in 18 of 28 cases (64.3 %). All positive cases by ISH showed detectable P21 WAF1/Cip1 protein reactivity by IHC. No relationship was found between P21 WAF1/Cip1 staining and P53 mutational status. No associations were seen with tumor metastasis, size and tumor grade, except for tumor differentiation status which showed higher frequency of P21 WAF1/Cip1 expression in moderate well differentiated HCCs than poorly differentiated tumors ( P <0.05). It is concluded that expression of P21 WAF1/Cip1 is common in HCCs, but does not correlate with P53 mutational status or pathological parameters investigated except for tumor differentiation. Also, there may be other factors beside P53 that regulate P21 WAF1/Cip1 gene expression in HCCs.
文摘Objective To determine the expression of P53 and P21 (WAF1/CIP1) in thyroid carcinomas and its relationship with development and prognosis of the carcinoma. Methods 90 cases of thyroid tissues (60 thyroid carcinomas, 10 thyroid adenomas, 10 goitres and 10 normal thyroid tissues) were studied by SP immunohistochemical method. Results Positive immunoreactivity of P53 and P21(WAF1/CIP1) was found only in thyroid carcinomas. The positive rate of the P53 and P21 is 53.3% and 41.7% respectively. The positive-staining rates of P53 were higher in cases of undifferentiated carcinomas, positive metastasis lymph nodes or in stage Ⅲ, Ⅳ than those in the cases of well-differentiated, no metastasis lymph nodes, or in stage Ⅰ,Ⅱ. In addition, the positive-staining of P21(WAF1/CIP1) were lower in cases of undifferentiated carcinomas, positive metastasis lymph nodes or stage Ⅲ, Ⅳ than that in the cases of well-differentiated, no metastasis lymph nodes or in stage Ⅰ,Ⅱ. The P21 (WAF1/CIP1) expression rate in the P53 positive group was lower than that in the P53 negative group (P<0.05). Conclusion The expression of P21(WAF1/CIP1) protein in thyroid cancer is related to P53-depend pathway and P53-independent pathway, mainly the P53-depend pathway. Examination of expression of P53 and P21 (WAF1/ CIP1) proteins may be helpful to judge the thyroid cancer's behavior and prognosis.
文摘Objective: To investigate the post-transcriptional regulation of p21WAF1/CIP1 by p53. Methods: The MDA-MB-468 cells have endogenous mutant p53 and the MCF7 cells lines have wtp53. Recombinant p53 expression and p21WAF1/CIP1 induction were detected by Western blot analysis. Northern blot analysis was carried out to examine whether changes in p21WAF1/CIP1 protein levels in MCF7 cells treated with AdCMVp53 are reflected at the mRNA level. Flow cytometric analysis of MCF7 cells following overexpression of recombination. Results: The ratio of p53: p21WAF1/CIP1 was below 1 at the early stages of AdCMVp53 infection, but increased to 1.6 by day 3 and to 9.7 by day 5 post-infection. As expected, p21WAF1/CIP1 expression was not detectable in MDA-MB-468 cells despite the presence of high levels of mutant p53 protein. The G1/S ratios in untreated controls and AdCMVβgal infected MCF7 cells were 1.10 and 1.35, respectively. By Northern blot analyzing the p21WAF1/CIP1: GAPDH ratios at different time points against the ratio at time point 0, a maximum 3-fold induction of p21WAF1/CIP1 mRNA expression relative to untreated control was observed on day 1 post-infection. The flow cytometric analysis indicated that MCF7 cells infected with AdCMVp53 undergo G1 arrest at both time points studied, with G1/S ratios ranging from 5.54 at day 1 to 5.65 at day 7. The G1/S ratios in untreated controls and AdCMVβgal infected MCF7 cells were 1.10 and 1.35, respectively. Conclusion: This study demonstrated that p53 could regulate p21WAF1/CIP1 gene expression at both the transcriptional and post-transcriptional levels in MCF7 cells. The latter mechanism may be involved in or be responsible for, the induction of cell cycle arrest by transcription-defective mutants of p53.
文摘Background:High-dose ultraviolet (UV) A1 therapy (doses in the order of 130 J cm-2) is effective for atopic dermatitis and scleroderma. UVA1 has been shown to induce a dose-dependent increase in p53 expression in keratinocytes. Objectives:To examine the effect of UVA1 on the activation of p53 by phosphorylation, which has not yet been studied. Methods:Five adult volunteers were exposed to dose series of UVA1 (10-100 J cm-2) and, for comparison, narrowband UVB (TL-01) (25-550 mJ cm-2) and solar-simulated radiation (SSR) (5.6-30 J cm-2)on photoprotected buttock skin and the minimal erythema dose (MED) for each was determined at 24 h. Separate sites on the buttock were subsequently irradiated with a 3-MED dose of UVA1, TL-01 and SSR. At 24 h, punch biopsies (4 mm) were taken from each irradiated site and from an adjacent unirradiated control site, and immunohistochemical staining for p53 (Do-1), activation of p53 (assessed by phosphorylation at serine 12 and serine 392) and p21 was performed. Cell staining was expressed as the mean number of cells stained per three high-power fields (HPFs) and as a percentage of 1000 cells. Sunburn cells (SBCs)were also counted per HPF. Results UVA1 produced negligible numbers of SBCs, relatively little p53 (Do-1) staining (mean±.SD cell count per HPF 16±10),no p53 activation and very little evidence of p21 expression (mean±SD cell count per HPF 5.3±7), in contrast to TL-01 (mean±SD cell count per HPF of 11.83±2.1 SBCs, 146.3±38 for Do-1, 26.6±15 for serine 15, 14.9±12 for serine 392 and 77.9±30 for p21) or SSR irradiation (mean±SD cell count per HPF of 3.5±1.2 SBCs, 147.5±62 for Do-1, 54±50 for serine 15, 38.9±18 for serine 392 and 56.7±30 for p21). Conclusions:These data indicate that there are fundamental differences in the effects of UVA1 on p53 and its activation pathways compared with TL-01 and SSR, and may in part explain the differential effects of these phototherapies.
