COX-2及COX-2抑制剂对肿瘤防治作用的研究进展

目的:通过大量文献研究可知,COX-2除了在发热、炎症、出凝血机制等过程中发挥着重要的作用,还与肿瘤发生、发展以及转移密切相关,所以本文通过对COX-2在肿瘤中的表达方式及COX-2抑制剂对肿瘤防治作用进行综述,以期为肿瘤的防治找到更加有效的新疗法。     

Livin和COX-2在尖锐湿疣组织中的表达和意义

目的探讨凋亡抑制蛋白Livin和COX-2在尖锐湿疣(CA)中的表达及意义。方法采用免疫组化SP法检测Livin和COX-2蛋白在52例CA和12例正常上皮中的表达。结果 CA中Livin和COX-2蛋白阳性表达率分别为76.92%(40/52)、61.54%(32/52),对照组Livin和COX-2蛋白阳性表达率分别为16.67%(2/12)、8.33%(1/12);CA中Livin和COX-2蛋白表达强度为(++)~(+++),对照组为(–)~(+);阳性表达率及表达强度差异均有统计学意义(P<0.05)。CA中Livin和COX-2表达呈正相关(r=0.591,P<0.01)。结论CA中Livin和COX-2过表达可能对CA发生发展有一定作用。     

ERK1/2介导H_2O_2预处理对抗氧化应激损伤的保护作用

目的探讨H2O2预处理能否激活ERK1/2及ERK1/2在H2O2预处理引起的适应性细胞保护中的作用。方法在PC12细胞,建立H2O2预处理对抗高浓度H2O2诱导细胞损伤的实验模型。应用甲氮甲唑蓝(MTT)法检测细胞存活率;碘化丙啶(PI)染色流式细胞术检测细胞凋亡率;免疫印迹法(Western blot)测定ERK1/2蛋白的表达及procaspase-3的表达。结果100μmol.L-1H2O2预处理PC12细胞90min能明显地保护PC12细胞对抗300μmol.L-1H2O2引起的损伤,使细胞存活率增加,细胞凋亡率降低及procaspase-3增多。H2O2预处理对ERK1/2具有明显的激活作用:诱导胞质ERK1/2磷酸化及促进其核转移。在H2O2预处理前30min应用ERK1/2抑制剂UO126(10μmol.L-1)可明显地阻断H2O2预处理的抗细胞毒性及抗细胞凋亡作用。结论H2O2预处理能激活ERK1/2,ERK1/2介导H2O2预处理的适应性细胞保护作用。     

赤芍801对小鼠巨噬细胞COX-1和COX-2活性、mRNA及蛋白表达的影响

目的研究赤芍801(propyl gallate,PrG)对环氧酶(cy-c looxygenase,COX)活性、mRNA及蛋白表达的影响。方法采用基于小鼠腹腔巨噬细胞的COX-1和COX-2体外筛选模型,用钙离子导入剂(calc ium ionophore A23187)短时刺激小鼠腹腔巨噬细胞,测定培养上清液中的6酮--前列腺素F1α(6-keto-PGFlα)的量反映COX-1活性;用脂多糖(lipopolysac-charide,LPS)长时间刺激细胞,测定培养上清液中的前列腺素E2(PGE2)的量反映COX-2活性。半定量RT-PCR法检测PrG对LPS刺激的Raw小鼠巨噬细胞COX-1、COX-2 mRNA表达的影响。W estern b lot法检测PrG对LPS刺激的Raw小鼠巨噬细胞COX-1、COX-2蛋白表达的影响。结果PrG体外10,5μmol.L-1浓度下不影响6-keto-PGFαl生成(P>0.05),而在1,0.5,0.1,0.05μmol.L-1浓度下则诱导6-keto-PGF1α生成(P<0.01),并呈较好的剂量依赖性。PrG体外1,10μmol.L-1可抑制PGE2生成(P<0.05)。PrG不同浓度对LPS刺激的Raw小鼠巨噬细胞COX-1、COX-2 mR-NA表达无明显影响。PrG(100,10,1μmol.L-1)浓度下可抑制COX-2蛋白表达,但对COX-1蛋白表达无影响。结论在0.05~10μmol.L-1浓度范围内,PrG低浓度时促进6-keto-PGF1α生成,高浓度时抑制PGE2生成,提示其高浓度时抑制COX-2,低浓度时激活COX-1;不同浓度PrG对COX-1、COX-2 mRNA表达均无明显影响。PrG(1~100μmol.L-1)浓度下可抑制COX-2蛋白表达,但对COX-1蛋白表达无影响。     

COX-2在乳腺癌组织中的表达及临床意义

目的　研究环氧化酶 2在乳腺癌组织和癌旁组织中的表达情况与临床病理指标之间的相关性。方法　以免疫组化SP法检测 4 7例乳腺癌以及癌旁组织标本。结果　 4 7例癌组织标本中阳性率为5 3 2 % (2 5 / 4 7)显著高于癌旁组织 (6 38% ,3/ 4 7) ,在淋巴结转移阳性组和阴性组以及不同组织学分级的病人之间COX 2的表达差异有显著意义 (P <0 0 5 ) ,而与病人年龄、月经情况、肿瘤大小、临床分期、ER、PR等差异无显著意义 (P >0 0 5 )。结论　乳腺癌组织中存在环氧化酶 2的高表达 (5 3 2 % ) ,并与淋巴结转移和组织学分级有关 ,环氧化酶 2在乳腺癌的发生发展中可能扮演重要角色     

H_2O_2预处理对PC12细胞氧化应激损伤的适应性细胞保护作用

目的　探讨H2 O2 预处理对PC12细胞氧化应激损伤的适应性细胞保护作用及与脑源性神经营养因子 (brain de rivedneurotrophicfactor,BDNF)的关系。 方法　采用MTT法检测细胞活力 ,PI染色流式细胞术检测细胞凋亡 ,间接免疫荧光流式细胞术检测细胞BDNF的表达。结果　PC12细胞经 10 μmol·L-1H2 O2 预处理 90min后 ,2 0～ 6 0 μmol·L-1H2 O2 对PC12细胞生长的抑制程度明显下降 ,H2 O2 (2 0、30μmol·L-1)对PC12细胞凋亡的诱导作用明显受到抑制 ,BD NF的表达强度增强。结论　H2 O2 预处理对PC12细胞氧化应激损伤具有保护作用 ,其作用机制可能与增加脑源性神经营养因子表达有关     

COX-2在乳腺癌患者癌组织及血清中的表达及临床意义

乳腺癌是威胁当今女性健康的主要疾病之一。乳腺癌的侵袭和转移是导致患者死亡的主要原因,有效监控和及时发现肿瘤转移,是合理采用综合治疗方案治愈乳腺癌的关键。大量研究表明环氧化酶-2在恶性肿瘤,如前列腺癌、乳腺癌、结直肠肿瘤的发病机制中起着非常重要的作用。环氧化酶-2参与肿瘤的发生发展及转移,包括抑制凋亡和促进增殖,促进新生血管生成,增加肿瘤细胞的侵袭性等多方面的     

环氧合酶-2及其抑制剂在胰腺癌血管靶向治疗中的作用

胰腺癌的诊治目前仍是医学界的难题,血管生成是胰腺癌生长和转移的必要因素。环氧合酶(cyclooxygenase,COX)为花生四烯酸代谢过程中的关键酶,存在COX-1及COX-2两种同工酶,其中COX-2在胰腺癌的发生发展及胰腺癌血管生成中发挥重要作用。COX-2抑制剂可分为非选择性及选择性两种,两种COX-2抑制剂都对胰腺癌及其血管形成的发生与进展存在抑制作用,COX-2抑制剂抗肿瘤血管形成的机制可能是抑制血管内皮生长因子(VEGF)、缺氧诱导因子-1及基质金属蛋白酶(MMP)的表达、降低前列腺素(PGs)及其他血管生成因子的表达、促进内皮细胞凋亡、抑制内皮细胞侵袭力和影响一氧化氮合酶(NOS)的表达。     

环氧化酶2过表达对铝盐致大鼠海马神经元损伤的影响

目的:研究环氧化酶2(COX-2)过表达与铝盐致大鼠海马神经元损伤间的关系.方法:原代海马神经元培养7d,予以铝盐负荷(终浓度200 μmol/L )建立大鼠海马神经元损伤模型,以神经元转染COX-2过表达腺病毒(MOI=100),Western Blot检测COX-2的蛋白表达水平,酶化学法检测海马神经元超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、乳酸脱氢酶(LDH)漏出率及MTT值,倒置荧光显微镜观察海马神经元病理形态变化.结果:COX-2过表达腺病毒转染的神经元COX-2蛋白表达增加(P＜0.01),SOD活性、MDA含量、LDH漏出率、MTT值,以及大鼠海马神经元细胞的形态和结构未见明显异常变化.而COX-2过表达腺病毒转染在铝盐负荷基础上的海马神经元细胞MTT值和SOD活性明显下降,LDH漏出率和MDA含量明显上升(P＜0.01或P＜0.05),表现为严重的细胞损伤.结论:单纯的一定程度COX-2过表达不会造成神经元明显损伤,但可增加神经元对铝盐损伤的敏感性.     

Chemoprevention of Colon Carcinogenesis by Oleanolic Acid and Its Analog in Male F344 Rats and Modulation of COX-2 and Apoptosis in Human Colon HT-29 Cancer Cells

PURPOSE: To assess the chemopreventive effect of oleanolic acid (ONA) and its synthetic analog 18alpha-olean-12-ene-3beta-23,28-triol (OT) on azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) in F344 rats and understand anti-inflammatory properties and apoptosis effects in HT29 colon cancer cells and Raw 264.7 macrophage cell lines. METHODS: Five week-old male F344 rats were fed a control diet or experimental diets containing two doses of ONA (750 and 1,500 ppm) and OT (250 and 500 ppm). After 1 week, all animals were s.c. injected with AOM (15 mg/kg body weight, once weekly for 2 weeks). At 14 weeks of age, all rats were killed and colons were evaluated for ACF. Cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) expressions and apoptosis were assessed in cell lines exposed to OT using western blots and 4',6-diamidino-2-phenylindole staining. RESULTS: Administration of ONA and OT inhibited mean colonic ACF and multi-crypt AC/foci in a dose dependent manner (p < 0.001-0.0001). OT blocked the COX-2 expression induced by phorbol 12-myristate 13-acetate in a dose-dependent manner and induced apoptosis in HT-29 cancer cells, and suppressed iNOS activation in RAW264.7 macrophages. CONCLUSIONS: ONA and OT possess chemopreventive activity against colon carcinogenesis in rat and OT inhibits the COX-2 and iNOS and induces apoptosis in cell lines.     

Anti-inflammatory potential of Antrodia Camphorata through inhibition of iNOS, COX-2 and cytokines via the NF-kappaB pathway

Antrodia camphorata (A. camphorata), well known in Taiwan as a traditional Chinese medicine, has been shown to exhibit antioxidant and anticancer effects. In the present study, therefore, we have examined the effects of the fermented culture broth of A. camphorata (25-100 microg/ml) in terms of lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production, and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in RAW 264.7 macrophages. Our results indicate concentration-dependent A. camphorata inhibition of LPS-induced NO and PGE2 production, without appreciable cytotoxicity on the RAW 264.7 cells. A. camphorata also attenuates the production of LPS-induced tumor necrosis factor (TNF-alpha) and interleukin (IL)-1beta. Furthermore, A. camphorata blocks the IkappaB-alpha degradation induced by LPS. These results indicate that A. camphorata inhibits LPS induction of cytokine, iNOS and COX-2 expression by blocking NF-kappaB activation. Therefore, we report the first confirmation of the anti-inflammatory potential of this traditionally employed herbal medicine in vitro.     

COX-1, COX-2 and the topical effect in NSAID-induced enteropathy

The side effects of NSAIDs are equally evident in the stomach and the small bowel. The latter is increasingly seen as being clinically significant, contributing substantially to the iron-deficiency anaemia that is so common in patients with rheumatoid arthritis. Furthermore, NSAID-enteropathy may be associated with life-threatening events. The pathogenesis of NSAID-enteropathy is uncertain but inhibition of COX-1 is believed to be of pivotal importance. However there is increasing evidence that COX-2 inhibition and the topical effect may have a synergistic detrimental action. We examined the role of COX-1, COX-2 and the so called topical effect of acidic NSAIDs. We found that COX-1 or COX-2 inhibition and the topical effect alone do not damage the GI tract. Dual inhibition of COX-1 and COX-2 results in intestinal inflammation similar to that caused by Indomethacin. The topical effect may act synergistically in this damage. The conventional view that the mechanism of gastrointestinal damage is principally caused by COX-1 inhibition needs to be revised in view of recent studies using selective inhibitors of the COX enzymes and COX knockout animals.     

ERK信号转导途径在小檗碱抑制脂多糖诱导的COX一2表达中的作用

目的探讨小檗碱是否抑制脂多糖诱导的COX-2mRNA及蛋白表达,以及小檗碱是否通过ERK信号转导途径抑制cOx-2的表达。方法取健康志愿者外周血,分离及培养单核细胞,分为五组,分别为对照组;脂多糖（Lipopolysaccharide,LPS）组;LPS＋小檗碱25μmol／L组;LPS＋小檗碱50μmol/L组;LPS＋小檗碱100μmoL／L组。分别在培养后30min,6h,12h,24h提取细胞,行RT—PCR法测定COX-2mRNA水平,行westemblot法测定ERK、P—ERK及COX-2蛋白水平。同时加入选择性ERK抑制剂,分别测定C0X-2mRNA及蛋白水平。结果与对照组相比,LPS组COX-2mRNA及蛋白表达明显增强（P〈0．01）。与LPS组相比,小檗碱组COX-2mRNA及蛋白表达明显抑制（P〈0．05）,且随着浓度增加,抑制作用更明显,在给药后12h,小檗碱对COX-2抑制作用最强。与LPS组相比,小檗碱组ERK活性水平有明显统计学差异（P〈0．05）。加入ERK抑制剂之后,COX-2mRNA及蛋白水平降低明显（P〈0．05）。结论小檗碱能抑制人外周血单核细胞cOx-2mRNA及蛋白水平,其作用程度呈浓度依赖性,小檗碱对ERK活性蛋白表达有明显抑制作用。小檗碱可能通过ERK信号转导途径抑制人外周血单核细胞C0x_2mRNA及蛋白表达。