| Colorectal cancer (CRC) is a common kind of malignant cancer. In recent years, some studies have indicated that in most of CRC,there has been an activating mutation of theβ-catenin correlation signaling pathway.The β-catenin correlation signaling pathway plays critical roles in cell proliferation and differentiation in many stages of development, and the β-catenin is the center component in the pathway. Aberrant β-catenin signaling pathway, which generally results from inactivating mutation of adenomatous polyposis coli(APC) or activating mutation of β-catenin, leads to the accumulation of β-catenin in the nucleus of cells, which is subsequently complexed with T-cell factor (Tcf) and promotes transcription of a variety of target genes,ultimately leading to cell aberrantly proliferation and tumor formation. Caffeic acid phenethyl ester (CAPE) is a phenolic antioxidant. As an active component of propolis, CAPE has many biological and pharmacological activities including anti-inflammatory, antiviral, antibacterial and antitumor. Studies have indicated that CAPE possesses chemopreventive effects on some human tumor cells, including leukemic cell, CRC cell and so on. CAPE may arrest cell proliferation and induct cell apoptosis. But the mechanism of antitumor is unclear. Some studies have found that the antitumor effect of CAPE is associated with aberrant β-catenin signaling pathway in CRC. But what link causes the effects? Is there the change of gene or protein expression? The answer to these questions are unknow. They remain matters for further investigation.Objective: (1)To investigate the expression and clinical significance of β-catenin, cyclinD1 and c-myc in colorectal mucosa, colorectal adenoma, colorectal adenoma with malignant transformation and CRC.To study the role of the mutuality component of β-catenin correlation pathway in the carcinogenesis and progression of CRC.(2) To observe the effect of CAPE on proliferation, cell cycle, apoptosis in the cultured human colorectal cancer cell line HCT116(wild-type APC,mutantβ-catenin) and SW480(wild-type β-catenin,mutant APC).(3)To study the influence of CAPE on the mutuality component of β-catenin correlation pathway including the mRNA and protein expression of β-catenin, c-myc and cyclinD1 in colorectal cancer cell lines. To explain the effect and mechanism of CAPE on CRC. Methods: The expression of β-catenin, cyclinD1 and c-myc in normal colorectal mucosa, colorectal adenoma , colorectal adenoma with malignant transformation and CRC was detected by immunohistochemistry method. HCT116 and SW480 cells were treated with CAPE at serial concentrations .The proliferative status of cells was measured by using methabenzthiazuron (MTT) assay. Cell cycle was analyzed by using flow cytometry (FCM) with propidium iodide (PI) labeling method. The rate of apoptosis was detected by using FCM with Annexin V-FITC and PI double labeling method. The subcellular localization expression of β-catenin in cells after CAPE treated was determined by immunofluorescence.Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting assay were used to evaluate the mRNA and protein level ofβ-catenin, cyclinD1 and c-myc in HCT116 and SW480 cells treated by CAPE at different concentrations for 24h and 48h.Results:(1) In normal colorectal mucosa, β-catenin was detected on the cell membrane. Reduced membrane expression, increased cytoplasmic and nuclear expression were detected in the colorectal adenoma, adenoma with malignant transformation and CRC. The cytoplasmic and nuclear expression rates of β-catenin were 85.7% in colorectal adenoma with malignant transformation and 63.1% in CRC, which were significantly higher than that in colorectal adenoma(P<0.05). The reduced membrane expression rate of β-catenin was 31.3% in colorectal adenoma, 52.4% in colorectal adenoma with malignant transformation and 70.8% in CRC.The reduced membrane expression rate in CRC was higher than that in colorectal adenoma(P<0.01).The cytoplasmic and nuclear expression rate of...
|
PDF Full Text Request