n-3多不饱和脂肪酸的肿瘤治疗作用及其机制

0引言 n-3(ω-3)脂肪酸是一类第一个不饱和键出现在碳链甲基端第三位的多不饱和脂肪酸(polyunsaturated fatty acid,PUFA),它具有多种生物学功能,近年来其在肿瘤治疗中的作用尤其受到关注[1],它可能通过几种途径起作用,但确切机制尚不明确.其中核转录因子-кappaB(nuclear factor-кB,NF-кB)是它的靶因子之一,研究表明n-3 PUFA可通过抑制NF-кB活性起到抗肿瘤的作用.     

血红素加氧酶-1与肿瘤的研究进展

血红素加氧酶-1(HO-1)是一种重要的抗炎、抗凋亡、抗氧化及耐药相关基因。在生理状态下,人体正常组织中的HO-1蛋白呈低表达。在遭受酒精、辛辣及热烫等持续刺激时,其表达升高。HO-1的表达异常与肿瘤的生物学行为密切相关。近年来研究发现,其基因多态性及分解血红素产生的代谢产物(胆红素、Fe²⁺、CO)参与的多条信号通路的激活,并影响多种肿瘤疾病的发生、发展。另外,在许多肿瘤中HO-1表达水平上调,不仅影响肿瘤微环境中氧化应激水平对肿瘤细胞生长及增殖的调节,而且还能诱导肿瘤细胞产生耐药性。因此,HO-1表达异常可能参与了肿瘤的发生发展。     

血红素加氧酶对肝癌耐药细胞株Bel/Fu化疗敏感性的影响

目的:评估血红素加氧酶(HO)对肝癌耐药细胞化疗敏感性的影响,探讨HO对肝癌细胞多药耐药性可能的影响机制.方法:血红素加氧酶抑制剂锌卟啉(ZnPP)和诱导剂Hemin作用于Bel/Fu肝癌耐药细胞株,分别应用MTT、RT-PCR和流式细胞术检测细胞株对化疗药物敏感性、血红素加氧酶-1(HO-1)及多药耐药基因(MDR-1)核酸水平表达量与P-糖蛋白(P-GP)功能.结果: Hemin作用于Bel/Fu细胞诱导24 h后,化疗药物半数抑制浓度明显增加(P<0.01),HO-1mRNA表达明显增加(F=71.513, P<0.05),MDR-1mRNA的表达量显著增加(F=2 340, P<0.01),且呈剂量依赖趋势,ZnPP干预组表现则相反;MDR-1cDNA/β-actin的表达量呈现与HO-1cDNA/β-actin平行变化的趋势,两者呈直线正相关(r=0.992, a=-0.044, b=1.223);Hemin组罗丹明荧光曲线明显左移,且浓度越高曲线左移越明显,而ZnPP组则表现为曲线右移,出现相反的结果.结论:影响HO-1的表达可改变肝癌耐药细胞株的化疗敏感性,这种变化是通过影响MDR-1表达,改变P-GP药物外排功能实现的;HO-1可作为逆转肿瘤多药耐药的潜在作用靶点.     

血红素加氧酶-1与肿瘤细胞凋亡

0 引言 细胞凋亡是由于内外环境变化或死亡信号触发,在相关基因调控下引起的细胞主动死亡过程,在胚胎发育、组织器官塑型以及衰老和病态细胞清除中起重要作用.各种环境因素和遗传因素可导致细胞凋亡率降低,进而引起人体多种疾病,同时也是肿瘤发生、发展的关键因素之一.血红素加氧酶-1(heme oxygenase,HO-1)作为人体最广泛的抗氧化防御酶,在多种刺激条件下发挥抗炎、抗氧化及抑制细胞凋亡等重要生物学作用,近年来越来越多的研究表明,HO-1及其代谢终产物对细胞的保护作用与肿瘤细胞增殖等生物学行为密切相关,同时也是肿瘤产生治疗抵抗的重要因素.本文将围绕HO-1及其与凋亡蛋白的关系,重点阐述HO-1在肿瘤抗凋亡过程中的研究进展.     

贝伐单抗治疗恶性肿瘤相关不良反应的发生机制及处理方法

肿瘤生长和增殖过程中需要新生血管的形成,而血管内皮生长因子(VEGF)在其中起重要的作用.VEGF家族包括VEGF-A、VEGF-B、VEGF-C、VEGF-D等多个相关因子,而在肿瘤新生血管形成中最重要的是VEGF-A因子,它可促进血管内皮细胞生长、增殖,并与血管内皮细胞产生的生长因子受体相结合,激活下游信号转导通路,最终促进新生血管的生成.贝伐单抗(Bevacizumab)是与VEGF结合的重组人源化单克隆抗体,能与VEGF-A结合,阻止其与VEGF受体的相互作用,起到抗新生血管形成的作用,进而抑制肿瘤生长.     

腹腔镜胃癌根治术对胃癌患者血清血红素加氧酶-1和肿瘤坏死因子-α及C反应蛋白的影响

目的探讨腹腔镜胃癌根治术对胃癌患者血清血红素加氧酶-1(HO-1)、肿瘤坏死因子-α(TNF-α)和C反应蛋白(CRP)水平的影响。方法选取2017年3月至2018年3月间陕西省铜川矿务局中心医院收治的98例胃癌患者,根据手术方式不同分为腹腔镜组(50例)和开腹组(48例)。腹腔镜组患者采用腹腔镜D2根治术,开腹组患者采用开腹D2根治术,比较两组患者手术前后血清HO-1、TNF-α及CRP水平。结果腹腔镜组患者术中出血量、手术时间、术后排气时间和术后下床活动时间均低于开腹组,差异均有统计学意义(均P <0. 05)。术前,两组患者HO-1、TNF-α和CRP指标水平比较,差异均无统计学意义(均P> 0. 05)。术后,两组患者HO-1、TNF-α和CRP指标水平均高于术前,而腹腔镜组患者各指标水平均低于开腹组,差异均有统计学意义(均P <0. 05)。结论腹腔镜D2根治术创伤小,抑制胃癌患者血清HO-1、TNF-α及CRP的释放,降低炎症反应,提高患者预后。     

NF—кB信号传导途径对TNF—α诱导的SMMC—7721细胞凋亡的影响

背景与目的：已证明核因子кB（nuclear factor-кB,NF-кB)在免疫细胞激活,抗病毒,多种应激反应和细胞凋亡的调控等许多方面起着重要作用。本实验研究NF-кB信号传导途径对TNF-α诱导的肝癌细胞株SMMC-7721细胞凋亡的影响。方法：采用ELISA和免疫组化检测TNF-α对NF-к信号传导通路的激活作用,继而用TPCK（n-tosyl-Phe-chloromethylketone)阻断NF-кB的活化,流式细胞仪检测细胞凋亡。结果：（1）TNF-α能激活NF-кB信号传导通路;（2）TPCK能抑制TNF-α诱导的NF-кB活化;（3）TPCK抑制NF-кB活化后,能加强TNF-α诱导的细胞凋亡,结论：SMMC-7721细胞中NF-кB细胞传导途径参与了细胞的抗凋亡过程,在SMMC-7721细胞对TNF-α的细胞毒性作用耐受中起重要作用,抑制NF-кB信号传导途径可能在肿瘤治疗中有潜在的应用价值。     

癌相关成纤维细胞通过Gro-α激活NF-кB核转位和VEGF表达促进卵巢癌的生长

背景与目的：卵巢癌相关成纤维细胞(cancer-associated fibroblasts,CAF)促进上皮肿瘤的发生,其分泌的趋化因子即生长调节致癌基因α(growth-regulated oncogene alpha,Gro-α)蛋白在肿瘤间质微环境中促进上皮卵巢癌的发生,但其作用机制并不清楚。本研究拟测定Gro-α蛋白是否通过激活间质成纤维细胞中NF-кB核转位和VEGF表达,促进卵巢癌的生长。方法：本研究采用ELISA法测定了两株卵巢癌CAF和两株正常卵巢组织成纤维细胞(normal fibroblasts,NF)条件培养基(conditioned medium,CM)中Gro-α的表达;用CAF-CM或Gro-α分别处理NF,并以NF-кB抑制剂处理作为对照;用蛋白质印迹法(Western blot)测定样品处理前后NF-кB和血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)等分子的变化;然后用CAF或NF分别与卵巢癌细胞系OVCA429混合接种BALB/c裸小鼠,或在有、无NF-кB抑制剂PS1145处理的NF中,用CAFCM或Gro-α处理后,分别与OVCA429混合接种动物,观察和比较动物移植瘤生长及移植瘤组织中微血管形成情况。结果：Gro-α在CAF中比在NF中高5～6倍;与对照组相比,用CAF条件培养基或Gro-α处理的NF中NF-кB p65的核转位升高,且VEGF上升,但血管生成抑制因子-血小板反应蛋白1下降;用NF-кB抑制剂同时处理NF,可以逆转其VEGF和TSP-1的表达水平;动物试验结果发现CAF要比NF更易促进肿瘤生长,而CAF-CM或Gro-α处理的NF细胞可以促进动物移植瘤的快速增长和移植瘤组织中微血管的生成,但用NF-кB抑制剂处理的NF则抑制肿瘤生长和血管形成能力。结论：卵巢癌CAF在肿瘤微环境中通过自分泌Gro-α,激活NF-кB核转位和VEGF表达,促进卵巢癌组织血管增生和肿瘤的生长。     

低氧条件下血红素加氧酶1过表达对人肝癌细胞的保护作用

目的 探讨低氧条件下人肝癌细胞(HepG2)中血红素加氧酶1(HO-1)过表达对细胞的保护作用,及其与低氧诱导因子1α(HIF-1α)的关系.方法 应用低氧气体(0.5%O2、94.5%N2、5%CO2)和化学模拟低氧(250 μmol/L CoCl2)方法 刺激HepG2细胞.采用逆转录聚合酶链反应(RT-PCR)方法 ,从mRNA水平上检测低氧条件下HO-1和HIF-1α的表达.采用Western bolt方法 ,从蛋白水平上检测低氧条件下HO-1和HIF-1α的表达及其相关性.采用四甲基偶氮唑蓝(MTT)方法 ,分析低氧刺激后细胞的存活率,以及低氧刺激同时抑制HO-1蛋白表达后细胞的存活率.采用超氧化物歧化酶(SOD)试剂盒,检测低氧刺激细胞后总SOD的活性,以及抑制HO-1蛋白表达后细胞中总SOD的活性.结果 低氧诱导的HepG2细胞中,HO-1 mRNA和蛋白过表达.用锌原卟啉IX(ZnPPIX)抑制低氧条件下HO-1蛋白过表达,可导致HepG2细胞在低氧应激条件下存活率明显降低(P<0.01).低氧条件下,HepG2细胞中总SOD的活性显著升高(P<0.05);而在抑制低氧条件下HO-1蛋白过表达后,HepG2细胞中总SOD活性明显降低(P<0.01).低氧条件下,HIF-1α蛋白表达显著升高,抑制HIF-1α蛋白表达后,HO-1蛋白表达明显降低;而抑制低氧条件下HO-1的过表达后,HIF-1α蛋白表达没有明显改变.结论 低氧诱导HepG2细胞中HO-1蛋白的过表达依赖或部分依赖HIF-1α;HO-1的过表达对HepG2细胞抵抗低氧应激发挥保护作用;HO-1的过表达对处于低氧应激条件下细胞的保护作用可能源于SOD.     

乳腺癌溶骨性骨转移相关因子

乳腺癌溶骨性骨转移主要是通过激活破骨细胞引起的.在这一过程中,乳腺癌细胞、成骨细胞和骨基质细胞通过分泌一系列相关因子促进骨转移发生.这些因子大多通过转录核因子-кB (NF-кB)相关的机制激活破骨细胞.最近研究发现白细胞介素-8(IL-8)通过NF-кB无关的机制激活破骨细胞.这些因子有可能成为乳腺癌防治的新靶点.     

Heme oxygenase-1: a molecular brake on hepatocellular carcinoma cell migration

Hepatocellular carcinoma (HCC) is a fatal disease with great public health impact worldwide. Heme oxygenase (HO)-1 has recently been reported as an important player in tumor angiogenesis and metastasis. However, the role of HO-1 in liver cancer metastasis is unclear. In this study, we explored genetic differences and downstream signal transduction pathways of HO-1 in liver cancer cell lines. HO-1 wild-type and mutant cell lines were generated from human liver cancer cell line HepG2. The overexpression of wild-type HO-1 decreased the migration of HepG2 cells. In contrast, the overexpression of mutant HO-1G143H increased the migration of the cancer cells. Interleukin (IL)-6 is one of the major downstream molecules that mediated this process because IL-6 expression and migration are suppressed by HO-1 and increased when HO-1 is knocked down by shRNA. In addition, we demonstrated carbon monoxide (CO) and p38MAPK are the cofactors in this signal pathway. In vivo animal model demonstrated HO-1 inhibited the tumor growth. In conclusion, in vitro and in vivo data show HO-1 inhibits the human HCC cells migration and tumor growth by suppressing the expression of IL-6. The heme degradation product CO is a cofactor in this process and inhibits p38MAPK phosphorylation.     

Co-expression of Thymidine Phosphorylase and Heme Oxygenase-1 in Macrophages in Human Malignant Vertical Growth Melanomas

Expression of thymidine phosphorylase (TP) is often associated with tumor angiogenesis and/or prognosis in patients. Further, infiltration of macrophages is closely correlated with the depth of tumor and angiogenesis in melanomas. In this study, we examined the expression of TP and an activated macrophage-specific enzyme, heme oxygenase-1 (HO-1), involved in malignancy in 22 cases with melanomas. TP was strongly expressed not only in CD68-positive macrophages in and around tumors, but also in S100 protein-positive melanoma cells, fibroblasts and keratinocytes. By contrast, HO-1 was specifically expressed in macrophages, but only slightly in melanoma cells and other cell types in the stroma of melanomas. We thus observed apparent co-expression of TP and HO-1 in macrophages infiltrating in the late stage of malignant melanomas. There appeared increasing numbers of TP-positive cells in Clark level IV and V melanoma compared with Clark level I ( in situ ) melanoma, and there was also a close correlation between numbers of TP-positive cells and HO-1-positive cells. Both TP- and HO-1-positive macrophages could be observed in the stroma in and around tumors in vertical growth melanomas.     

Co-expression of thymidine phosphorylase and heme oxygenase-1 in macrophages in human malignant vertical growth melanomas.

Expression of thymidine phosphorylase (TP) is often associated with tumor angiogenesis and / or prognosis in patients. Further, infiltration of macrophages is closely correlated with the depth of tumor and angiogenesis in melanomas. In this study, we examined the expression of TP and an activated macrophage-specific enzyme, heme oxygenase-1 (HO-1), involved in malignancy in 22 cases with melanomas. TP was strongly expressed not only in CD68-positive macrophages in and around tumors, but also in S100 protein-positive melanoma cells, fibroblasts and keratinocytes. By contrast, HO-1 was specifically expressed in macrophages, but only slightly in melanoma cells and other cell types in the stroma of melanomas. We thus observed apparent co-expression of TP and HO-1 in macrophages infiltrating in the late stage of malignant melanomas. There appeared increasing numbers of TP-positive cells in Clark level IV and V melanoma compared with Clark level I (in situ) melanoma, and there was also a close correlation between numbers of TP-positive cells and HO-1-positive cells. Both TP- and HO-1-positive macrophages could be observed in the stroma in and around tumors in vertical growth melanomas.     

Carbon monoxide, generated by heme oxygenase-1, mediates the enhanced permeability and retention effect in solid tumors

The enhanced permeability and retention (EPR) effect is a unique pathophysiological phenomenon of solid tumors that sees biocompatible macromolecules (>40 kDa) accumulate selectively in the tumor. Various factors have been implicated in this effect. Herein, we report that heme oxygenase-1 (HO-1; also known as heat shock protein 32) significantly increases vascular permeability and thus macromolecular drug accumulation in tumors. Intradermal injection of recombinant HO-1 in mice, followed by i.v. administration of a macromolecular Evans blue-albumin complex, resulted in dose-dependent extravasation of Evans blue-albumin at the HO-1 injection site. Almost no extravasation was detected when inactivated HO-1 or a carbon monoxide (CO) scavenger was injected instead. Because HO-1 generates CO, these data imply that CO plays a key role in vascular leakage. This is supported by results obtained after intratumoral administration of a CO-releasing agent (tricarbonyldichlororuthenium(II) dimer) in the same experimental setting, specifically dose-dependent increases in vascular permeability plus augmented tumor blood flow. In addition, induction of HO-1 in tumors by the water-soluble macromolecular HO-1 inducer pegylated hemin significantly increased tumor blood flow and Evans blue-albumin accumulation in tumors. These findings suggest that HO-1 and/or CO are important mediators of the EPR effect. Thus, anticancer chemotherapy using macromolecular drugs may be improved by combination with an HO-1 inducer, such as pegylated hemin, via an enhanced EPR effect.     

Inhibition of heme oxygenase 1 expression by small interfering RNA decreases orthotopic tumor growth in livers of mice

Endogenous overexpression of the antiapoptotic protein heme oxygenase 1 (HO-1) has been shown to occur in various cancer diseases and might contribute to cancer progression. We compared the expression levels of HO-1 in human liver to expression levels in hepatocellular carcinoma (HCC), as well as the effect of HO-1 inhibition by small interfering RNA (siRNA) on cellular survival and apoptosis in the mouse hepatoma cell lines Hepa129 and Hepa1-6 and on orthotopic tumor growth in immune-competent C3H/HeN mice. Our results show that HO-1 is frequently overexpressed in human HCC. Downmodulation of HO-1 by siRNA resulted in increased cellular damage and apoptosis, reduced proliferation, reduced growth of orthotopic HCC and reduced angiogenesis. Livers and kidneys of treated animals did not reveal signs of damage by this treatment. In conclusion, a specific knockdown of HO-1 might represent a novel therapeutic approach in HCC therapy.     

Macrophage infiltration and heme oxygenase-1 expression correlate with angiogenesis in human gliomas.

Macrophages are key participants in angiogenesis. In this study on human brain tumors, we first investigated whether macrophage infiltration is associated with angiogenesis and malignant histological appearance. Immunostaining of macrophages and small vessels in resected glioma specimens indicated that numbers of infiltrating macrophages and small vessel density were higher in glioblastomas than in astrocytomas or anaplastic astrocytomas. Macrophage infiltration was closely correlated with vascular density in human gliomas. Heme oxygenase-1 (HO-1), which is the rate-limiting enzyme in heme catabolism, was also associated with activated macrophages. Expression of mRNA encoding HO-1 was correlated with macrophage infiltration and vascular density in human glioma samples. Infiltrating macrophages were positively stained with anti-HO-1 antibody by immunohistochemical analysis, and in situ hybridization for HO-1 indicated that HO-1 was expressed in infiltrating macrophages in gliomas. HO-1 gene may be a useful marker for macrophage infiltration as well as neovascularization in human gliomas.     

Anticancer potential of diarylidenyl piperidone derivatives,HO-4200 and H-4318, in cisplatin resistant primary ovarian cancer

We have previously developed a novel class of bi-functional compounds based on a diarylidenyl-piperidone (DAP) backbone conjugated to an N-hydroxypyrroline (-NOH; a nitroxide precursor) group capable of selectively inhibiting STAT3 activation, translocation, and DNA binding activity. HO-4200 and H-4318 are 2 such derivatives capable of inducing apoptosis in ovarian cancer cells through this mechanism and demonstrated efficacy in platinum resistant primary ovarian cancer cell populations and tumor tissues. The improved absorption and cellular uptake of HO-4200 by cancer cells was determined using optical and electron paramagnetic resonance spectrometry. Treatment of ovarian cancer cells with HO-4200 and H-4318 resulted in cleavage of caspase proteins 3, 7, and 9, as well as PARP and inhibition of the pro-survival protein, Bcl-xL, resulting in significantly decreased cell survival and increased apoptosis. HO-4200 and H-4318 significantly inhibit fatty acid synthase (FAS) and pSTAT3 and decreased the expression of STAT3 target proteins: Survivin, c-myc, Bcl-xl, Bcl-2, cyclin D1/D2, and VEGF were suppressed as analyzed using quantitative real time PCR. In addition, HO-4200 and H-4318 significantly inhibited migration/invasion, in primary ovarian cancer cell populations isolated from primary and recurrent ovarian cancer patients. Treatment of freshly collected human ovarian tumor sections with HO-4200 demonstrated significant suppression of pSTAT3 Tyr 705, angiogenesis (VEFG), and markers of proliferation (Ki-67) in ex vivo models. We have shown, for the first time, that the DAP compounds, HO-4200 and H-4318, inhibit cell migration/invasion and induce apoptosis by targeting FAS/STAT3 in human ovarian cancer cells, including primary ovarian cancer cell populations and tumor tissues. Therefore, our results highlight the clinical anti-cancer potential of HO-4200 and H-4318.