AIM: p73, as a novel member of a family of p53-related transcription factors, shares redundant functions with p53, such as the abilities of inducing apoptosis and suppressing growth. It is well known that p53 can repr...AIM: p73, as a novel member of a family of p53-related transcription factors, shares redundant functions with p53, such as the abilities of inducing apoptosis and suppressing growth. It is well known that p53 can repress HBV expression and transcription efficiently. The aim of this paper is to investigate the transcriptional effect of p73α and p73β on hepatitis B virus (HBV) and to understand the correlation between HBV and p73.METHODS: To construct an x-gene inactivated HBV plasmid which was cotransfected with p73α or p73β expression vectors into HepG2 cells. After transiently transfecticn, HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) were detected by ELISA. Viral transcripts synthesized by HBV were evaluated by Northern blotting analysis. The activities of HBV regulatory elements, including enhancer Ⅰ/X promoter (ENI/Xp) and enhancer Ⅱ/core promoter (ENⅡ/Cp) were monitored by luciferase assays.RESULTS: Both p73α and p73β could repress HBsAg and HBeAg expression by downregulating the ENⅠ/Xp and ENⅡ/Cp activities. But p73β exerted stronger inhibition on the activity of ENI/Xp than p73α, resulting in much lower level of viral transcripts and the antigens expression.CONCLUSION: p73β as a novel member of p53 family can efficiently inhibit HBV transcription mainly through downregulating the activities of the HBV ENI/Xp regulatory elements.展开更多
Objective: To study the effects of transferred wild type p73α gene on the sensitivity to the chemotherapeutic agents and the growth of p53-null H1299 cells of human lung adenocarcinoma. Methods: The pcDNA3-HA-p73α p...Objective: To study the effects of transferred wild type p73α gene on the sensitivity to the chemotherapeutic agents and the growth of p53-null H1299 cells of human lung adenocarcinoma. Methods: The pcDNA3-HA-p73α plasmid was transferred into the cultured p53-null H1299 cells of human lung adenocarcinoma with the mediation of Dosper liposome; The cells resistant to G418 were selected. The expression of p73α gene in the cells was examined with Western blot. MTT assay was used to analyze the response of the transfected cells to cis-dichlorodiamine platinum (cDDP) and adriamycin (ADM). The rate of drug-induced apoptosis of the transfected cells was determined with flow cytometry and DNA fragmentation assay. The changes of the biological behaviors were observed with colony formation assay. Results: The transfected H1299 cells of human lung adenocarcinoma over-expressed p73α protein stably. MTT assay showed that the IC 50 values of cDDP and ADM were reduced by approximately 7 fold and 130 fold respectively in the transfected cells as compared with the untransfected ones. Lower concentration of the chemotherapeutic agents (1.25 μmol/L of cDDP and 0.05 μmol/L of ADM) could be employed to suppress markedly the growth of the transfected H1299 cells. The apoptotic rate induced by cDDP was increased from 10.1% to 38 4% (P<0.01) and that of ADM from 12.1% to 49.3% (P<0.01). The clonogenecity after the administration of chemotherapeutic agents was significantly lower in the transfected H1299 cells than in the parental cells (P<0.01). The sensitive enhancement ratios were 1.8 and 2.6 for cDDP and ADM respectively. Conclusion: The transfection of H1299 cells with wild type p73α gene results in an increase of the sensitivity of the cells to chemotherapeutic agents.展开更多
Objective： To investigate the relationship between the expression of p73α and p53 versus the chemosensitivity in breast cancer cells. Methods： Twelve surgical samples of breast cancer diagnosed by pathology were us...Objective： To investigate the relationship between the expression of p73α and p53 versus the chemosensitivity in breast cancer cells. Methods： Twelve surgical samples of breast cancer diagnosed by pathology were used. The cancer sample cells were separately cultured in the incubator at 37℃, 5% CO2 in vitro. The relative inhibition rate of cancer cells by 4 kinds of anticancer drugs, which were EPI, MMC, 5-Fu and DDP, were assayed by MTT method. Immunocytochemistry was used to detect the expression of p73α and p53 in the cancer cells. Results： The positive expression of p73α was found in 5/12 （41.67%）, and p53 positive expression rate was 50.0% （6/12）. The relative inhibition rate of MMC, EPI, 5-Fu and DDP were significantly higher in the p73α positive cancer cells than in the p73α negative cancer cells. A positive correlation was found between expression of p73α and chemosensitivity for all the four anticancer drugs. Condusion： The expression of p73α is related with the chemosensitivity of the breast cancer cells, and it may become one of the markers for judging the effect of chemotherapy in clinic.展开更多
基金special funds for Major State Basic Research"973"of China,No.2001CB510205
文摘AIM: p73, as a novel member of a family of p53-related transcription factors, shares redundant functions with p53, such as the abilities of inducing apoptosis and suppressing growth. It is well known that p53 can repress HBV expression and transcription efficiently. The aim of this paper is to investigate the transcriptional effect of p73α and p73β on hepatitis B virus (HBV) and to understand the correlation between HBV and p73.METHODS: To construct an x-gene inactivated HBV plasmid which was cotransfected with p73α or p73β expression vectors into HepG2 cells. After transiently transfecticn, HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) were detected by ELISA. Viral transcripts synthesized by HBV were evaluated by Northern blotting analysis. The activities of HBV regulatory elements, including enhancer Ⅰ/X promoter (ENI/Xp) and enhancer Ⅱ/core promoter (ENⅡ/Cp) were monitored by luciferase assays.RESULTS: Both p73α and p73β could repress HBsAg and HBeAg expression by downregulating the ENⅠ/Xp and ENⅡ/Cp activities. But p73β exerted stronger inhibition on the activity of ENI/Xp than p73α, resulting in much lower level of viral transcripts and the antigens expression.CONCLUSION: p73β as a novel member of p53 family can efficiently inhibit HBV transcription mainly through downregulating the activities of the HBV ENI/Xp regulatory elements.
文摘Objective: To study the effects of transferred wild type p73α gene on the sensitivity to the chemotherapeutic agents and the growth of p53-null H1299 cells of human lung adenocarcinoma. Methods: The pcDNA3-HA-p73α plasmid was transferred into the cultured p53-null H1299 cells of human lung adenocarcinoma with the mediation of Dosper liposome; The cells resistant to G418 were selected. The expression of p73α gene in the cells was examined with Western blot. MTT assay was used to analyze the response of the transfected cells to cis-dichlorodiamine platinum (cDDP) and adriamycin (ADM). The rate of drug-induced apoptosis of the transfected cells was determined with flow cytometry and DNA fragmentation assay. The changes of the biological behaviors were observed with colony formation assay. Results: The transfected H1299 cells of human lung adenocarcinoma over-expressed p73α protein stably. MTT assay showed that the IC 50 values of cDDP and ADM were reduced by approximately 7 fold and 130 fold respectively in the transfected cells as compared with the untransfected ones. Lower concentration of the chemotherapeutic agents (1.25 μmol/L of cDDP and 0.05 μmol/L of ADM) could be employed to suppress markedly the growth of the transfected H1299 cells. The apoptotic rate induced by cDDP was increased from 10.1% to 38 4% (P<0.01) and that of ADM from 12.1% to 49.3% (P<0.01). The clonogenecity after the administration of chemotherapeutic agents was significantly lower in the transfected H1299 cells than in the parental cells (P<0.01). The sensitive enhancement ratios were 1.8 and 2.6 for cDDP and ADM respectively. Conclusion: The transfection of H1299 cells with wild type p73α gene results in an increase of the sensitivity of the cells to chemotherapeutic agents.
文摘Objective： To investigate the relationship between the expression of p73α and p53 versus the chemosensitivity in breast cancer cells. Methods： Twelve surgical samples of breast cancer diagnosed by pathology were used. The cancer sample cells were separately cultured in the incubator at 37℃, 5% CO2 in vitro. The relative inhibition rate of cancer cells by 4 kinds of anticancer drugs, which were EPI, MMC, 5-Fu and DDP, were assayed by MTT method. Immunocytochemistry was used to detect the expression of p73α and p53 in the cancer cells. Results： The positive expression of p73α was found in 5/12 （41.67%）, and p53 positive expression rate was 50.0% （6/12）. The relative inhibition rate of MMC, EPI, 5-Fu and DDP were significantly higher in the p73α positive cancer cells than in the p73α negative cancer cells. A positive correlation was found between expression of p73α and chemosensitivity for all the four anticancer drugs. Condusion： The expression of p73α is related with the chemosensitivity of the breast cancer cells, and it may become one of the markers for judging the effect of chemotherapy in clinic.
