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1.
The p53 pathway is commonly altered during oral and skin carcinogenesis. The lip is a transition tissue between skin and oral mucosa, which in response to UVB exposure also exhibits alterations in the expression of p53 and p53-related genes that could lead to malignant transformation. To assess if the p53-regulated proteins murine-double-minute (mdm)-2 and p21 are altered during early lip carcinogenesis, biopsies from normal lip (n=16) and the premalignant lip lesion, actinic cheilitis (AC) (n=26) were processed for the immunohistochemical detection of p53, p21 and mdm-2 in serial co-localized sections. Epithelial co-expression of p53 and mdm-2 was significantly increased in AC as compared to normal lip (P<0.001). No differences in epithelial p21 expression were found between normal lip and AC. While in normal lip mdm-2 and p21 were significantly correlated with p53, in AC only mdm-2 was associated with p53 expression. Multivariate logistic regression analysis of the three markers (Wald stepwise) showed that p53 is the only predictor of AC. The results point to alterations in the p53 pathway during early lip carcinogenesis, highlighting p53 as a potential marker of early malignancy of the lip.  相似文献   

2.
To investigate the effects of cyclooxygenase-2 (COX-2) overexpression on breast cancer development, we stably transfected MCF-10F human breast epithelial cells with an expression vector containing human COX-2 cDNA oriented in the sense (10F-S) or antisense (10F-AS) direction. As expected, 10F-S cells expressed elevated levels of COX-2 protein, whereas this protein was undetectable in the 10F-AS cells. Prostaglandin E(2) production in these cells reflected COX-2 levels. The 10F-S cells had a significantly decreased rate of proliferation compared to 10F-AS or parental cells, and a delay in progression through the G(1) phase of the cell cycle. COX-2 overexpression also caused resistance to detachment-induced apoptosis (anoikis) as well as an inhibition of differentiation in cells cultured in Matrigel. Furthermore, after approximately 20 passages in culture, 10F-S cells developed fibroblast-like features, expressed vimentin, and formed foci of dense growth when cultured at confluence, suggesting that the cells were undergoing epithelial to mesenchymal transition (EMT). The 10F-S cells, however, were unable to grow in soft agar or form tumors in nude mice, suggesting that they were only partially transformed. Our observations suggest that COX-2 overexpression in human breast epithelial cells will predispose the mammary gland to carcinogenesis.  相似文献   

3.
Cyclooxygenase (COX)-2, the inducible form of the rate-limiting enzyme for prostaglandin synthesis, is up-regulated in gastrointestinal cancers and is a key mediator of epithelial cell growth. Helicobacter pylori is causally linked to gastric cancer. In H. pylori gastritis, COX-2 expression localizes to the subepithelial region, with variable levels in the epithelium. In contrast, in gastric cancer, COX-2 strongly predominates in the epithelium, suggesting that the transition to consistent epithelial COX-2 overexpression may be a critical molecular event in gastric carcinogenesis. Because aberrant promoter methylation inhibits expression of a variety of genes in gastrointestinal cancers, we sought to determine whether methylation of the COX-2 promoter could regulate the response to H. pylori in gastric epithelial cells. We assessed COX-2 expression and promoter methylation status in six gastric epithelial cell lines. In all four of the cell lines that exhibited basal expression of COX-2 and a significant increase in expression in response to H. pylori, the COX-2 promoter was unmethylated, whereas in the two cell lines that did not express COX-2, the COX-2 promoter was methylated. Treatment of COX-2-methylated cells with the demethylating agent 5-azacytidine had a modest effect on COX-2 expression, but when 5-azacytidine-treated cells were subsequently stimulated with H. pylori, there was a significant, 5-10-fold enhancement of both COX-2 mRNA and protein expression and release of the COX-2 product, prostaglandin E2. In contrast, in COX-2-expressing cell lines that were unmethylated at the COX-2 promoter, 5-azacytidine had no effect on H. pylori-stimulated COX-2 expression. These findings suggest that loss of COX-2 methylation may facilitate COX-2 expression and promote gastric carcinogenesis associated with H. pylori infection.  相似文献   

4.
Despite maturation arrest, blast cells in acute myeloid leukemia (AML) are often capable of expressing lineage-restricted (granulomonocytic or myelomastocytic) differentiation antigens. Tryptases are lineage-associated serine proteases primarily expressed in mast cells, and less abundantly in blood basophils. We have recently shown that myeloblasts in a group of patients with AML (approximately 40%) produce significant amounts of tryptase(s). In these patients, serum tryptase levels are elevated (> 15 ng/ml) and reflect the total burden of leukemic cells. In most cases, myeloblasts express alpha-tryptase mRNA in excess over beta-tryptase mRNA, and secrete the respective protein (= pro-alpha-tryptase) in a constitutive manner. It was also found that these AML blasts frequentlyco-express tryptase with additional mast cell lineage- and/or basophil-related differentiation antigens including KIT (CD117), histamine, and 2D7. We hypothesize that tryptase-positive AMLs arise from a leukemic progenitor that exhibits a limited potential to differentiate into mast cells and/or basophils.  相似文献   

5.
BACKGROUND AND OBJECTIVES: Protease-activated receptor-2 (PAR-2) is a G protein-coupled receptor that is activated by trypsin. Recent studies have suggested that PAR-2 activity correlates with inflammatory processes and cell proliferation and that PAR-2 activation in non-neoplastic cells induces expression of cyclooxygenase-2 (COX-2). In the present study, we examined whether PAR-2 activation regulates cell proliferation and COX-2 expression by pancreatic cancer cells. METHODS: We analyzed PAR-2 expression immunohistochemically in 40 intraductal papillary-mucinous neoplasms (IPMNs) and 73 invasive ductal carcinomas (IDCs) of the pancreas. We used four pancreatic cancer cell lines (Panc1, T3M4, BxPC3, and MIApaca2) to measure cell proliferation and COX-2 mRNA expression after PAR-2 activation. RESULTS: PAR-2 protein was detected immunohistochemically in 85.0% of IPMNs and 65.8% of IDCs. Trypsin and a PAR-2 agonist peptide, SLIGKV, stimulated proliferation of each cell line in a dose-dependent manner. Exposure of cells to anti-PAR-2 neutralizing antibody prior to PAR-2 activation suppressed cell proliferation. In COX-2-positive cell lines (T3M4 and BxPC3), PAR-2 activation significantly increased COX-2 mRNA expression. CONCLUSIONS: Our results suggest that PAR-2 activation is associated with cell proliferation and COX-2 expression in pancreatic cancer cells. Blockade of the PAR-2 signaling pathway may be a novel strategy for suppressing pancreatic tumor growth.  相似文献   

6.
PURPOSE: Recent data support the hypothesis that the inducible isoform of cyclooxygenase (COX-2) plays a role in the early stages of colonic carcinogenesis and that nonsteroidal anti-inflammatory drugs (NSAIDs) retard the development of colon cancer by modulating COX-2. However, the cell types responsible for producing COX-2 in colorectal adenomas remain a subject of controversy. EXPERIMENTAL DESIGN: COX-2 expression in normal colonic mucosa (n = 50), hyperplastic polyps (n = 43), sporadic adenomas (n = 67), and invasive colonic adenocarcinoma (n = 39) was studied in formalin-fixed and paraffin-embedded tissue sections from endoscopy biopsy and colonic resection specimens. Immunohistochemistry (avidin-biotin complex technique with double immunolabeling) was used to identify the phenotypes of COX-2-producing cells. RESULTS: In colorectal adenomas, increased expression of COX-2 was detected and localized to alpha smooth muscle actin ( proportional, variant SMA)-positive subepithelial stromal cells (myofibroblasts) in the periluminal region of the lamina propria in 63 (94%) of 67 cases. In contrast, in normal colonic mucosa and in hyperplastic polyps with intact epithelium, COX-2 expression was found only in macrophages and endothelial cells. In areas in which the surface epithelium was ulcerated in normal mucosa as well as hyperplastic or neoplastic polyps, COX-2 expression was increased in granulation tissue (and present in macrophages, endothelium, and myofibroblasts). In invasive carcinoma, COX-2 expression in myofibroblasts was limited to the adenomatous portion of the tumor and was detected in 62% of cases (n = 39). In addition, focal expression of COX-2 by malignant epithelial cells was observed in 23% of invasive adenocarcinoma. CONCLUSIONS: These results show that increased COX-2 expression in sporadic adenoma of the colon is common and is localized specifically to subepithelial intestinal myofibroblasts. These findings further support the hypothesis that myofibroblasts are important target cells for NSAID-mediated chemoprevention of colorectal cancer.  相似文献   

7.
Yu HP  Xu SQ  Liu L  Shi LY  Cai XK  Lu WH  Lu B  Su YH  Li YY 《Cancer letters》2003,198(2):193-201
  相似文献   

8.
During the process of activation, mast cells release products stored in their granules. Tryptase, a protease released from mast cell granules after activation, induces tumor cell proliferation through the activation of PAR-2 (protease activated receptor 2) on the plasma membrane of carcinoma cells. Chemical cancerization (DMBA) of the hamster cheek pouch is the most accepted model of oral cancer. However, there are no reports on the activation of mast cells during experimental carcinogenesis or on the correlation between mast cell activation and cell proliferation. The aim of the present study was to evaluate the potential effect of mast cells on the proliferation of epithelial cells at different times during the cancerization process. Paraffin serial sections of cancerized, tumor-bearing pouches were stained with Alcian Blue-Safranin to identify the different degrees of mast cell activation. Immunohistochemistry was performed to identify BrdU-positive cells to study tumor cell proliferation. Mast cells were counted and grouped into two categories: inactive mast cells AB-S+++ (red) and active mast cells AB+++S- (blue). Mast cell counts were performed in tumor stroma, base of the tumor (connective tissue immediately below the exophytic tumor), connective and muscle tissue underlying the cancerized epithelium (pouch wall) and adventitious tissue underlying the pouch wall. There was a significant increase in the number of mast cells at the base of tumors (p<0.001) compared to the number of mast cells in the wall of the pouch and in tumor stroma. In normal non-cancerized pouches, inactive mast cells were prevalent both in the wall (AB:S=1:2.15; p<0.001) and in the adventitious tissue (AB:S=1:1.6; p<0.004) of the hamster cheek pouch. At most of the experimental times examined, the ratio of active/inactive mast cells (AB/S) in the wall approximated unity and even reverted. The ratio of mast cells was AB:S 1:1.05 at the base of the tumor and 1:0.24 in tumor stroma (p<0.001). The evaluation of epithelial nuclei labeled for BrdU revealed a statistically significant increase in cells undergoing DNA synthesis in the epithelium of the wall of the cancerized pouch compared to control (p<0.017). Tumor parenchyma exhibited a highly statistically significant increase in DNA synthesis compared to control (p<0.001) and compared to the epithelium of the wall of the cancerized pouch (p<0.036). We conclude that mast cell activation in this model is associated to the increase in tumor cell proliferation, conceivably mediated by the release of tryptase.  相似文献   

9.
Nuclear Factor-kappaB (NF-kappaB) activation and COX-2 overexpression have been reported in head and neck cancer, but the relationship between these proteins remains to be investigated. To determine the relationship between NF-kappaB and COX-2 in Smokeless Tobacco (ST) associated oral tumorigenesis, we performed immunohistochemistry in serial sections from 107 OSCCs, 78 oral precancerous lesions (OPLs) (58 hyperplasias, 20 dysplasias) and 15 histologically normal oral tissues and correlated with clinicopathological data. Significant increase in NF-kappaB and COX-2 immunopositivity was observed from normal oral mucosa to OPLs to OSCCs (p = 0.009 and p = 0.002 respectively). Upregulation of NF-kappaB and COX-2 was observed as early as in hyperplasia [p = 0.006; OR = 6.1 and p = 0.003; OR = 7.6, respectively]. Expression of both proteins was found to be significantly associated in OPLs (p = 0.000; OR = 12.6) and OSCCs (p = 0.001; OR = 4.0). Intriguingly, khaini consumption correlated with NF-kappaB immunopositivity in OPLs (p = 0.05, OR = 3.8) and OSCCs (p = 0.01, OR = 3.4) and with COX-2 expression in OPLs (p = 0.03; OR = 4.3). In vitro experimental system of ST associated oral carcinogenesis was used to demonstrate ST (khaini) and NNK mediated activation of NF-kappaB and COX-2, supporting the clinical data. In conclusion, this study demonstrates correlation between over expression of NF-kappaB and COX-2 in early precancerous stages of development of oral cancer and sustained elevation down the tumorigenic pathway, underscoring their potential as targets for early intervention. In vitro studies demonstrated that NNK may be one of the carcinogenic components of ST (khaini) inducing activation of NF-kappaB and COX-2 in oral precancer and cancer cells, suggesting plausible role in ST-induced oral carcinogenesis.  相似文献   

10.
11.
目的探讨环氧合酶2(cyclooxygenase-2,COX-2)和血管内皮生长因子(vascularendothelial growthfactor,VEGF)在人胃癌组织中表达及其相关性。方法应用免疫组织化学SABC法检测53例人胃癌组织中COX-2、VEGF和CD34的表达,并以40例正常胃粘膜标本作为对照。对CD34阳性血管进行微血管密度(microvesseldensity,MVD)计数。对COX-2和VEGF的表达采用半定量计分法判定,并结合临床资料进行统计学分析。结果53例人胃癌组织中,COX-2表达阳性者44例,阳性率为83.0%;VEGF表达阳性者45例,阳性率为84.9%。COX-2表达与VEGF表达相关显著(P<0.05)。并且,COX-2和VEGF的表达与TNM分期(P<0.05,P<0.05)、淋巴结转移(P<0.01,P<0.05)和远处转移(P<0.01,P<0.05)相关。COX-2/VEGF同高表达组中MVD值(79.5±25.8)高于COX-2/VEGF同低表达组中的MVD值(45.0±13.9),差异非常显著(P<0.01)。结论胃癌组织中COX-2与VEGF共表达,并相互协同促进肿瘤血管生成和转移。  相似文献   

12.
卵巢癌中COX-2与VEGF-C的表达及对微淋巴管生成的影响   总被引:5,自引:0,他引:5  
辛刚  刘培淑  杜鹃  毛鸿鸾 《中国肿瘤》2005,14(7):474-477
[目的]探讨环氧合酶2(cyclooxygenase-2,COX-2)与血管内皮生长因子C(vascular endothelial growth facfor C,VEGF-C)在卵巢癌中的表达及其对微淋巴管生成的影响.[方法]应用免疫组化的方法检测正常卵巢、卵巢良性肿瘤、卵巢癌中COX-2、VEGF-C及微淋巴管密度(microlymphatic density,MLD).[结果]COX-2在卵巢癌中高表达,阳性率为71.1%,而在正常卵巢和良性卵巢肿瘤中未见表达.VEGF-C在卵巢癌中表达较正常卵巢和良性卵巢肿瘤中明显增加(P<0.01).COX-2、VEGF-C在卵巢癌中表达与临床分期、组织学类型、细胞分级无关(P>0.05),而与淋巴结转移有关(P<0.05).COX-2表达和VEGF-C呈等级相关(rs=0.415 P<0.01)、COX-2和VEGF-C均阳性者MLD数量较均阴性者增加(P<0.01).[结论]卵巢癌组织中存在COX-2、VEGF-C表达,COX-2可能通过VEGF-C促进肿瘤微淋巴管生成.  相似文献   

13.
Cyclooxygenase-2 (COX-2) is the inducible isoform of the rate-limiting enzymes that convert arachidonic acid to proinflammatory prostaglandins as well as a primary target for nonsteroidal anti-inflammatory drugs. Accumulating evidence suggests that up-regulation of COX-2 is associated with carcinogenesis in multiple organ systems including the large bowel, lung, breast, and prostate. In this report, we examine the expression of COX-2 protein and mRNA in prostate tissue containing various lesions and in prostate cancer cell lines. In the cell lines, LNCaP, DU145, PC-3, and TSU, COX-2 protein expression was undetectable under basal conditions but could be induced transiently by phorbol ester treatment in PC-3 and TSU cells, but not in DU145 and LNCaP cells. Immunohistochemical analysis of 144 human prostate cancer cases suggested that, in contrast to several previous reports, there was no consistent overexpression of COX-2 in established prostate cancer or high-grade prostatic intraepithelial neoplasia, as compared with adjacent normal prostate tissue. Positive staining was seen only in scattered cells (<1%) in both tumor and normal tissue regions but was much more consistently observed in areas of proliferative inflammatory atrophy, lesions that have been implicated in prostatic carcinogenesis. Staining was also seen at times in macrophages. Western blotting and quantitative RT-PCR analyses confirmed these patterns of expression. These results suggest that if nonsteroidal anti-inflammatory drugs are indeed chemopreventive and/or chemotherapeutic for prostate cancer, their effects are likely to be mediated by modulating COX-2 activity in non-PCa cells (either inflammatory cells or atrophic epithelial cells) or by affecting a COX-2-independent pathway.  相似文献   

14.
潘珊  吴绪峰  陈惠祯 《肿瘤》2007,27(1):46-50
目的:探讨上皮性卵巢癌组织中环氧化酶-2(cyclooxygenase-2,COX-2)表达与卵巢癌化疗耐药和预后的关系,以及与p53表达的相关性。方法:采用免疫组化SP法检测54例上皮性卵巢癌组织和20例正常卵巢组织中COX-2和p53表达,分析其与上皮性卵巢癌临床病理因素、化疗耐药的关系,同时对预后进行多因素的Cox生存分析。结果:COX-2和p53在上皮性卵巢癌组织中阳性表达率分别为48.1%和59.3%,正常卵巢组织均未见表达,差异有极显著性(P〈0.01);两者间表达呈显著正相关(P=0.01)。COX-2表达与患者病理类型、手术病理分期、病理分级及年龄无关,与术后残留灶直径有显著相关性(P〈0.01)。COX-2、p53阳性表达率在耐药组和非耐药组之间相比有显著差异(P〈O.01)。多因素生存分析显示,手术病理分期、COX-2表达和术后残留灶直径是影响患者预后的独立危险因素。结论:COX-2表达与上皮性卵巢癌组织化疗耐药相关,是影响患者预后的独立危险因素。COX-2表达与抑癌基因p53的突变可能具有相互促进作用,在卵巢癌化疗耐药中起重要作用。  相似文献   

15.
16.
17.
目的 研究环氧化酶 2 (COX 2 )在子宫内膜癌组织中的表达及其与血管生成的关系。方法 用免疫组化法检测42例子宫内膜癌和15例正常子宫内膜组织中COX 2的表达,并检测微血管密度(MVD)。结果 子宫内膜癌组织中COX 2、MVD明显高于正常子宫内膜组织(P <0 0 5 ) ,COX 2高表达与子宫内膜癌组织学分级和浸润深度有关(P <0 0 5 ) ,与临床分期、淋巴结转移和组织学分型无关(P >0 0 5 ) ,COX 2表达阳性者MVD明显高于COX 2表达阴性者(P <0 0 5 )。结论 COX 2过表达可能参与子宫内膜癌发生发展过程,且与子宫内膜癌新生血管形成有关。  相似文献   

18.
COX-2 overexpression increases motility and invasion of breast cancer cells   总被引:21,自引:0,他引:21  
Cyclooxygenase-2 (COX-2), an inducible enzyme involved in prostaglandin (including PGE(2)) biosynthesis, is overexpressed in several epithelial malignancies including breast cancer. We tested the hypothesis that COX-2 overexpression in breast cancer cells results in increased cell motility and invasion. COX-2 overproducing cells were generated by stable transfection of several human breast cancer cells with pSG5-COX2 vector. We confirmed the overexpression of COX-2 protein by western blotting, and by measuring PGE(2) in the medium with an immunoassay. We measured cell motility by counting the number of cells crossing an 8-micron pore size PET membrane, and cell invasion by counting the number of cells invading through a Matrigel-coated membrane that simulates basement membrane. COX-2 transfected MDA-231 cells produced 30-43-fold more PGE2 as compared to parental cells. COX-2 overexpression increased cell migration approximately 2.2-fold and cell invasion through Matrigel approximately 5.1-fold. Addition of 50 microM NS-398, a COX-2 inhibitor, inhibited Matrigel invasion of MDA-231 cells by 54% as compared to solvent confirming the role of COX-2 in cell invasion. It is known that an increase in cell migration and invasion can be brought about by cytoskeletal alterations and basement membrane degradation due to increased expression of pro-urokinase plasminogen activator (pro-uPA). To investigate the mechanism of our observed increase in cell invasion by COX-2, we found by western blotting that the level of pro-uPA was significantly higher (approximately 5-fold) in COX-2 transfected MDA-231 cells than untransfected MDA-231 cells. Similar to our observations in cell culture, we found evidence that increased COX-2 activity correlates with uPA in a mouse model of breast cancer metastasis to bone. In this study, we conclude that COX-2 overexpression in human breast cancer cells enhances cell motility and invasiveness thus suggesting a mechanism of COX-2 mediated metastasis.  相似文献   

19.
背景与目的:近期研究表明,环氧合酶(cyclooxygenase-2,COX-2)和诱导型一氧化氮合酶(induciblenitricoxidesynthase,iNOS)共同参与肿瘤的发生发展过程,但有关它们异常表达与舌鳞癌生物学行为的关系尚不清楚。本研究拟探讨COX-2和iNOS在舌鳞癌的表达和两者间的相互关系。方法:应用免疫组化SP法,检测59例舌鳞癌及其45例增生性病变(轻、中、重度不典型增生分别为22例、20例、3例)和36例癌旁正常鳞状上皮中COX-2蛋白、iNOS蛋白的表达情况,并对这些指标进行相关分析。结果:在癌旁正常鳞状上皮、轻、中、重度不典型增生上皮和舌鳞癌组织中,COX-2蛋白异常表达检出率分别为8.3%(3/36)、4.5%(1/22)、5.0%(1/20)、0(0/3)和45.8%(27/59);iNOS蛋白异常表达检出率分别为44.4%(16/36)、72.8%(16/22)、80.0%(16/20)、100.0%(3/3)和98.3%(58/59)。COX-2蛋白在癌旁正常鳞状上皮的表达,与舌鳞癌组织的表达差异有显著性(P<0.001),与不典型增生总体的表达差异无显著性(P>0.05);iNOS蛋白在癌旁正常鳞状上皮的表达,与不典型增生总体和癌组织的表达差异均有显著性(P<0.001)。等级相关分析结果显示,COX-2、iNOS表达异常与组织学分级均显著正相关(相关系数r分别为0.418和0.607,P值均<0.001),而且COX-2蛋白与iNOS蛋白之间也具有显著相关性(r=0.245,P<0.001)。结论:COX-2和iNOS蛋白异常表达与舌鳞癌癌变过程显著相关。  相似文献   

20.
Cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), and microvessel density (MVD) have been reported to be significantly related to carcinogenesis and to tumoral progression. The aim of the study was to analyse immunohistochemically the overexpression of COX-2 and VEGF, and the MVD between one another, and also in relation with clinical outcome in ovarian carcinoma. We selected 52 patients with ovarian carcinoma homogeneous by stage, type and histological grade, surgical and chemotherapeutic treatment. Of these, 28 patients had died of progression of their disease within 2 years of their primary surgical treatment, while 24 patients were alive with no evident disease at 5 years from the primary surgical treatment. The differences of the COX-2 status, the MVD and the VEGF expression in the two groups of ovarian carcinoma patients with low and high survival rate, respectively, were calculated according to the Fisher's exact test and the logistic regression. The shift in location of MVD in the two groups of patients was calculated according to the Wilcoxon Mann-Whitney test. MVD was correlated with COX-2 and VEGF overexpression (P=0.009 and P=0.003, respectively), COX-2 and VEGF were correlated to one another (P=0.044). In logistic regression analysis, COX-2, VEGF, and MVD were significant (P=0.017, P=0.008, P<0.0005, respectively). In the cases with low survival rate, the average MVD was 102, while in the cases with high survival rate the average MVD was 40.5 (P<0.0005). The evaluation of the COX-2, the VEGF and the MVD may give additional prognostic information for first-line chemotherapy and clinical outcome of patients with ovarian carcinoma and may encourage selection of more tailored therapies. Angiogenesis inhibitors or COX-inhibitors probably can have synergistic effects with chemotherapy.  相似文献   

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