Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.61 (caspase-8)
 6,833 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidemiologic studies reported that the prevalence of hereditary non-polyposis colon cancer (HNPCC) in male is about 1.5-fold higher than that in female. Decreases in circulatory estrogen (E(2)) have been reported to downregulate the expression of E(2) receptor (ER) and significantly increase the risk of colorectal cancer. Patients that received E(2) replacement therapy were found to have a reduction in the incidence of colon adenoma and carcinoma. Furthermore, significant decreases in the expression of ER have been found in colorectal cancer specimens. Evidences strongly suggest the protective roles of E(2) and ER against colorectal cancer. However, the mechanisms of ERalpha effects on colorectal cancer cells remained un-clear. LoVo cells were transient transfected to overexpress ERalpha, DNA fragmentation and the activated caspases measurements were performed to evaluate apoptotic effects. Western blotting was used to evaluate protein levels, and luciferase activity assay to measure the Htnf-a promoter activity. The results clearly demonstrated that overexpressed ERalpha with or without E(2) (10(-8) M) treatment could activate caspase -8, -9, and 3 and induce DNA fragmentation in LoVo cell. At the same time, overexpressed ERalpha plus E(2) significantly increases the expression and promoter activity of hTNF-alpha, and the DNA fragmentation effect induced by E(2) plus ERalpha were reduced by the addition of hTNF antibody (0.1 ng(ml). In addition, E(2) plus ERalpha significantly upregulated p21 and p27 levels and downregulated the beta-catenin and its target genes, cyclin D1 and Rb, which regulate the cell cycle and cell proliferation. The results indicate that E(2) plus overexpressed ERalpha induce LoVo cell apoptosis might mediate through the increase of hTNF-alpha gene expression, which in turn activate caspase-8, -9 and caspase-3 and lead to the DNA fragmentation and apoptosis. E(2) plus ERalpha also showed the downregulation of beta-catenin signalings implicating the suppression of proliferation and metastasis of colorectal cells. Efforts aiming at enhancing ERalpha expression and(or activity may be proved to be an alternative therapy against colorectal cancer.
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PMID:Over-expressed estrogen receptor-alpha up-regulates hTNF-alpha gene expression and down-regulates beta-catenin signaling activity to induce the apoptosis and inhibit proliferation of LoVo colon cancer cells. 1662 68

Epidemiologic studies reported that the prevalence of hereditary non-polyposis colon cancer (HNPCC) in male is about 1.5-fold higher than that in female. Decreases in circulatory estradiol (E2) have been reported to downregulate the expression of E2 receptor (ER) and significantly increase the risk of colorectal cancer. Patients that received E2 replacement therapy were found to have a reduction in the incidence of colon adenoma and carcinoma. Furthermore, significant decreases in the expression of ER have been found in colorectal cancer specimens. These data strongly suggest the protective roles of E2 and ER against colorectal cancer. However, the mechanisms remain unexplored. LoVo cells were transient transfected to overexpress ER-beta, DNA fragmentation and caspase activity assay were performed to evaluate apoptotic effects. Western blotting was used to evaluate protein levels, and luciferase activity assay to measure the TNF-alpha promoter activity. Our data clearly demonstrated that E2 and ER-beta alone could upregulate p21 and p27 proteins, which further activate caspase-8 and caspase-9 to induce apoptosis in LoVo cell, and the ER-beta. effects were enhanced by E2. However, overexpressed ER-beta did not influence the expression and promoter activity of TNF-alpha. In addition, E2 and overexpressed ER-beta downregulated the beta-catenin proteins which cause the downregulation of its target genes, cyclin D1 and Rb, to inhibit the cell cycle and cell proliferation. The results indicate that overexpressed ER-beta may induce LoVo cell apoptosis and anti-proliferation by increasing p53 signaling in a ligand-dependent manner, and without hTNF-alpha involvement. Efforts aiming at enhancing ER-beta expression and/or activity may prove to be an attractive alternative therapy against colorectal cancer.
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PMID:Apoptotic effects of over-expressed estrogen receptor-beta on LoVo colon cancer cell is mediated by p53 signalings in a ligand-dependent manner. 1683 Jul 93