iNOS和HO-1与肝癌的细胞增殖和凋亡的关系

目的:探讨原发性肝细胞癌(hepatocellular carcinoma,HCC)中,诱导型一氧化氮合酶(inducible nitricoxide synthase,iNOS)和血红素氧合酶-1(heme oxygneaseⅠ,HO-1)的表达情况及其与肝癌细胞增殖和凋亡的关系。方法:采用免疫组化S-P法检测56例HCC石腊组织标本和17例尸检正常肝标本中iNOS和HO-1的表达,同时检测以Ki67标记的细胞核增殖指数(proliferation index,PI)、抗凋亡基因BCL-2蛋白的表达,半定量评分系统评价染色结果。结果:肝癌组织中的iNOS、HO-1、抗凋亡基因BCL-2蛋白表达率分别为:83.3%、89.3%、71.4%,细胞核增殖指数为30.56±3.96%,上述各值均显著高于正常肝组织(P<0.01)。iNOS表达与细胞核增殖指数呈正相关,iNOS和HO-1的表达与抗凋亡基因BCL-2蛋白呈正相关(r=0.537,P<0.01和r=0.386,P<0.01)。结论:iNOS和HO-1的表达在促进HCC增殖和抑制HCC凋亡中发挥重要作用,有利于HCC生长。     

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.     

血红素加氧酶-1在肿瘤新生血管化中的作用

研究证明血红素加氧酶-1(HO-1)与一些促新生血管因子如血管内皮生长因子(VEGF)、基质细胞衍生因子-1等相互作用,促进肿瘤的新生血管化.另外,也有研究者认为血红素加氧酶-1可以通过抑制核因子-кB(NF-кB)转录来抑制肿瘤新生血管化过程.HO-1可能参与了肿瘤新生血管形成的病理生理过程,可能成为肿瘤治疗新的作用靶点.     

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.     

HO-1与MRP2在原发性胆囊癌组织中的表达和意义

目的:检测血红素加氧酶-1(heme oxygenase,HO-1)与多药耐药相关蛋白2 (multidrug resistance-associated protein 2,MRP2)在原发性胆囊癌组织中的表达,探讨其与胆囊癌发生、发展的关系.方法: 采用免疫组化SP法检测67例原发性胆囊癌患者中HO-1和MRP2的表达水平.结果: 原发胆囊癌组织HO-1和MRP2表达的总阳性率分别为73.1%、77.6%.其中腺癌的阳性率为76.7%和80%.依据病理分级,HO-1和MRP2表达水平由高到低分别为III级>II级>I级,且具有统计学差异(P=0.028,P=0.023);HO-1、MRP2的阳性表达与年龄、性别等临床特征无相关性;HO-1和MRP2表达之间具有良好的相关性(r=0.324,P=0.005).结论: HO-1和MRP2在原发性胆囊癌组织高表达,对胆囊癌的发生、发展提供有利条件,二者之间表达具有良好的相关性.     

血红素氧合酶-1在结直肠癌中的过表达与意义

目的:检测血红素氧合酶-1（heme oxygenase,HO-1）在良、恶性结直肠组织中的表达情况,探讨其在结直肠肿瘤发生发展中的作用。方法:采用免疫组化的方法检测118例结直肠癌、17例结直肠炎性息肉及20例结直肠癌周围正常组织患者的石蜡标本中HO-1的表达情况,使用图像分析系统测定阳性细胞的平均光密度值。结果:结直肠癌组织HO-1的平均光密度值随着肿瘤分化程度提高而上升,结直肠癌组织HO-1的平均光密度值高于炎性息肉及直肠癌周围良性组织,差异有统计学意义（P<0.05）。结直肠癌组织HO-1的平均光密度值与性别、TNM分期及淋巴结转移无关。结论:HO-1在结直肠癌中呈现高表达,与结直肠良性病变及癌变存在相关性,可能与结直肠癌的发生、发展及预后有关联。     

血红素氧合酶-1对人肝癌SMMC-7721细胞5-FU化疗敏感性的影响

目的:探讨血红素氧合酶-1(HO-1)对人肝癌SMMC-7721细胞5-氟尿嘧啶(5-FU)化疗敏感性的影响及其可能的机制.方法:应用不同浓度锌原卟啉(ZnPP)、氯化血红素(Hemin)单独或联合5-FU作用于人肝癌SMMC-7721细胞不同时间,MTT法观察药物对细胞生长抑制作用;蛋白质印迹法分析细胞HO-1蛋白表达变化;流式细胞术检测细胞凋亡率;Caspase-3活性检测试荆盒分析其凋亡机制.结果:ZnPP和5-FU均可明显抑制SMMC-7721细胞生长,呈剂量依赖性.5-FU联用ZnPP(20 μmol/L)显著增加细胞生长抑制率和凋亡率,P=0.000;而联用Hemin(10/μmol/L)显著降低细胞生长抑制率和凋亡率,P=0.000.SMMC-7721细胞中可见HO-1表达,应用Hemin和5-FU均能使其表达增强,联用ZnPP可逆转此现象.应用5-FU细胞内Caspase-3活性明显增高,约0.553±0.024,P=0.000;联用znPP后可进一步提高细胞内Caspase-3活性,达1.190±0.091,P=0.000.而联用Hemin后细胞内Caspase-3活性水平显著降低,约0.321±0.024,P=0.000.结论:阻断HO-1的表达可增强人肝癌SMMC-7721细胞对5-FU化疗敏感性,而诱导HO-1表达则降低人肝癌SMMC-7721细胞时5-FU化疗敏感性,这一作用机制可能与影响细胞Caspase-3活性有关.     

慢病毒介导的 HO-1基因沉默对人白血病K562细胞增殖与凋亡的影响

目的:研究沉默血红素加氧酶1(heme oxygenase-1,HO-1)基因对人慢性粒细胞性白血病(chronic myelogenous leu-kemia,CML)K562细胞增殖与凋亡的影响。方法:构建靶向HO-1基因的重组慢病毒Lv-siRNA-HO-1,将其感染K562细胞,荧光显微镜检测其最适感染复数(multipliciy of infection,MOI)。Western blotting检测Lv-siRNA-HO-1感染组、空载体Lv-Ctrl感染组及未感染组K562细胞中HO-1蛋白的表达,CCK-8法、流式细胞术分别检测各感染组K562细胞的增殖与凋亡。结果:成功构建靶向HO-1基因的干扰表达载体PSIH1-HO-1-siRNA,包装后形成重组慢病毒Lv-siRNA-HO-1,其有效感染K562细胞MOI值为6。与未感染组相比,Lv-siRNA-HO-1感染组K562细胞中HO-1蛋白的表达显著降低[(0.16±0.02)vs(0.70±0.02),P<0.01],K562细胞增殖活性也明显下降[(1.36±0.12)vs(2.02±0.17),P<0.01)],而K562细胞凋亡率则显著增加[(62.77±4.39)%vs(14.19±1.6)%,P<0.01]。结论:慢病毒介导的HO-1基因沉默能抑制人白血病K562细胞增殖和诱导其凋亡。     

血红素氧化酶-1在胃癌组织中的表达及意义

目的 研究人胃癌组织巾血红素氧化酶-1（HO-1）的表达情况。方法 采用免疫组化和RT—PCR等方法检测46例人胃癌组织（C组）、癌旁3cm组织（M组）和第1、2站淋巴结（L1、L2组）中HO-1的表达水平，并与正常胃组织作对照（N组）。结果 胃癌组织HO-1 mRNA表达水平最高，与M组、L1、L2组相比差异有统计学意义（P〈0．01）；M组、L1、L2组HO-1 mRNA表达显著强于N组（P〈0．05），但组间相比差异无统计学意义（P〉0．05）。结论 胃癌组织中HO-1呈高表达状态，可能对肿瘤细胞的生长提供有利条件。     

Twist基因介导肿瘤细胞耐药的研究进展

Twist属于高度保守的碱性螺旋-环-螺旋(basichelix-loop-helix,bHLH)结构的转录因子家族,在动物和人的胚胎发育、诱导细胞迁移以及组织塑形中起重要作用.Twist基因具有癌基因特征,在多种恶性肿瘤中高表达,不仅参与肿瘤的发生、侵袭和转移,而且与肿瘤细胞产生耐药性密切相关.Twist基因可以通过抗细胞凋亡、干扰抗微管类药物、诱发上皮-间质转型、诱导产生肿瘤干细胞样特性及影响肿瘤微环境等促使肿瘤细胞耐药,因此有望成为逆转肿瘤耐药的新靶点.     

Inhibition of heme oxygenase-1 increases responsiveness of pancreatic cancer cells to anticancer treatment.

Heme oxygenase-1 (HO-1) is believed to represent a key enzyme for the protection of cells against "stress." Its overexpression in different types of human cancers supports the notion that HO-1 provides a growth advantage and contributes to cellular resistance against chemotherapy and radiotherapy. Given the poor survival rates of patients with pancreatic cancer due to its aggressive growth behavior and its exceptional resistance to all known forms of anticancer treatment, we have investigated the expression of HO-1 in human pancreatic cancer cells growth behavior and prognosis. Expression of HO-1 was analyzed in human pancreatic cancer samples in comparison with normal pancreas by quantitative PCR, Western blot, and confocal microscopy. The influence of radiotherapy and chemotherapy on HO-1 expression in pancreatic cancer cell lines was evaluated. Furthermore, HO-1 expression was specifically suppressed by small interfering RNA transfection and subsequently the alterations of growth behavior and resistance to anticancer treatment were tested. Human pancreatic cancer showed a 6-fold and 3.5-fold HO-1 up-regulation in comparison to normal pancreas based on mRNA and protein level, respectively (P < 0.05). Cancer tissues revealed marked HO-1 immunoreactivity in tumor cells and in tumor associated immunocytes. Treatment of the pancreatic cancer cell lines with gemcitabine or radiation strongly induced HO-1 expression. Targeted knockdown of HO-1 expression led to pronounced growth inhibition of the pancreatic cancer cells and made tumor cells significantly more sensitive to radiotherapy and chemotherapy. Therefore, specific inhibition of HO-1 expression may be a new option in pancreatic cancer therapy and may be used as sensitizer to chemotherapy and radiotherapy.     

肿瘤相关基因NET-1的研究进展

NET-1(tspan1)是新近被证实的四次跨膜蛋白超家族(transmembrane 4 superfamily,TM4SF)的成员之一。作为一种肿瘤相关基因,与肿瘤细胞的增殖、迁移、内吞作用和诱导血管形成密切相关。NET-1蛋白的异常表达可能是引起和维持癌恶性表型的原因之一,其表达水平对癌的预后具有评估价值,该基因可能成为肿瘤基因治疗的靶点。     

碱基切除修复因子SmuG1与肿瘤的研究进展

肿瘤是严重威胁人类健康的疾病之一。随着研究的不断深入，人们发现DNA损伤在肿瘤发生发展中的作用不可忽视。DNA损伤发生后，机体识别损伤类型并启动相应的修复机制以维持机体的正常状态，其中DNA糖基化酶SmuG1作为碱基切除修复途径的关键启动蛋白，在保持真核生物的基因稳定性和遗传完整性中发挥重要作用。近年研究发现SmuG1在肿瘤组织中的异常表达，与肿瘤的病理类型、肿瘤细胞的侵袭转移以及患者生存率、药物耐药性均相关。SmuG1有望成为新的肿瘤标志物和潜在治疗靶点。     

Heme oxygenase-1 in macrophages controls prostate cancer progression

Innate immune cells strongly influence cancer growth and progression via multiple mechanisms including regulation of epithelial to mesenchymal transition (EMT). In this study, we investigated whether expression of the metabolic gene, heme oxygenase-1 (HO-1) in tumor microenvironment imparts significant effects on prostate cancer progression.We showed that HO-1 is expressed in MARCO-positive macrophages in prostate cancer (PCa) xenografts and human prostate cancers. We demonstrated that macrophage specific (LyzM-Cre) conditional deletion of HO-1 suppressed growth of PC3 xenografts in vivo and delayed progression of prostate intraepithelial neoplasia (PIN) in TRAMP mice. However, initiation and progression of cancer xenografts in the presence of macrophages lacking HO-1 resulted in loss of E-cadherin, a known marker of poor prognosis as well as EMT. Application of CO, a product of HO-1 catalysis, increased levels of E-cadherin in the adherens junctions between cancer cells. We further showed that HO-1-driven expression of E-cadherin in cancer cells cultured in the presence of macrophages is dependent on mitochondrial activity of cancer cells.In summary, these data suggest that HO-1-derived CO from tumor-associated macrophages influences, in part, E-cadherin expression and thus tumor initiation and progression.     

The synergistic effects of PRDX5 and Nrf2 on lung cancer progression and drug resistance under oxidative stress in the zebrafish models

Previous studies have shown that PRDX5 and Nrf2 are antioxidant proteins related to abnormal reactive oxidative species (ROS). PRDX5 and Nrf2 play a critical role in the progression of inflammations and tumors. The combination of PRDX5 and Nrf2 was examined by Co-immunoprecipitation, western blotting and Immunohistochemistry. H₂O₂ was applied to affect the production of ROS and induced multi-resistant protein 1 (MRP1) expression in NSCLC cells. The zebrafish models mainly investigated the synergistic effects of PRDX5 and Nrf2 on lung cancer drug resistance under oxidative stress. We showed that PRDX5 and Nrf2 form a complex and significantly increase the NSCLC tissues compared to adjacent tissues. The oxidative stress improved the combination of PRDX5 and Nrf2. We demonstrated that the synergy between PRDX5 and Nrf2 is positively related to the proliferation and drug resistance of NSCLC cells in the zebrafish models. In conclusion, our data indicated that PRDX5 could bind to Nrf2 and has a synergistic effect with Nrf2. Meanwhile, in the zebrafish models, PRDX5 and Nrf2 have significant regulatory impacts on lung cancer progression and drug resistance activities under oxidative stress.     

Decreased heme-oxygenase (HO)-1 in the macrophages of non-small cell lung cancer

Reactive oxygen species (ROS) are important in the initiation and promotion of cells to neoplastic growth. Heme-oxygenase (HO)-1, the inducible form of heme-oxygenase, is a cytoprotective enzyme that plays a central role in the defence against oxidative stress and is implicated in the protection of lung tissue against exogenous oxidant exposure. We investigated whether the expression of HO-1 would be decreased in lung tumour as compared with tumour-free adjacent lung tissues. HO-1 expression was quantified by immunohistochemistry in tumour macrophages, in macrophages of tumour-free lung and in tumour cells of surgical specimens collected from 53 individuals with surgically resectable non-small cell lung cancer (NSCLC). The expression of HO-1 was decreased in tumour as compared with tumour-free lung macrophages. No correlations were observed between the expression of HO-1 and both the clinicopathological characteristics and the overall survival of the examined subjects. In conclusion, our data show that macrophages of non-small cell lung cancer exhibit impaired anti-oxidant defence mechanisms, likely mediated by HO-1. Conversely, HO-1 expression does not seem to be associated with lung tumour progression and prognosis.     

AKT1 amplification regulates cisplatin resistance in human lung cancer cells through the mammalian target of rapamycin/p70S6K1 pathway

Cisplatin [cis-diaminodichloroplatinum (II) (CDDP)] is one of the most widely used and effective therapeutic agents for many kinds of cancers. However, its efficiency is limited due to development of drug resistance. In this study, we showed that CDDP resistance was associated with AKT1 overexpression and gene amplification in human lung cancer cells that acquired the drug resistance. We showed that AKT1 forced expression in the cells was sufficient to render the cells CDDP resistant, and that AKT1 inhibition by its dominant negative mutant reversed the CDDP-resistant cells to be CDDP sensitive. These results show that AKT1 activity is essential for regulating CDDP resistance in cultured lung cancer cells. To study whether these results were correlated with human lung cancer tumors, we randomly selected tumor samples from human lung cancer patients to study the correlation of AKT activation and CDDP resistance in clinical tumor samples. We showed that AKT activation was highly related to CDDP chemosensitivity in human tumor tissues. Our results further showed that AKT1 induced lung cancer cells to become resistant to CDDP through the mammalian target of the rapamycin (mTOR) signaling pathway. These studies conclude that AKT amplification and the mTOR pathway play an important role in human lung cancer cells acquiring CDDP resistance, which represents a new mechanism for acquiring CDDP resistance and a potential novel therapeutic target for overcoming CDDP resistance in human cancer in the future.     

Heme oxygenase-1 expression in human gliomas and its correlation with poor prognosis in patients with astrocytoma

In human glioma tumors, heme oxygenase-1 (HO-1) has been shown to be upregulated both when compared with normal brain tissues and also during oligodendroglioma progression. The cell types that express HO-1 have been shown to be mainly macrophages/microglia and T cells. However, many other reports also demonstrated that cell lines derived from glioma tumors and astrocytes express HO-1 after the occurrence of a wide variety of cell injuries and stressors. In addition, the significance of HO-1 upregulation in glioma had not, so far, been addressed. We therefore aimed at investigating the expression and significance of HO-1 in human glial tumors. For this purpose, we performed a wide screening of HO-1 expression in gliomas by using tissue microarrays containing astrocytomas, oligodendrogliomas, mixed tumors, and normal brain tissues. We subsequently correlated protein expression with patient clinicopathological data. We found differences in HO-1 positivity rates between non-malignant brain (22 %) and gliomas (54 %, p?=?0.01). HO-1 was expressed by tumor cells and showed cytoplasmic localization, although 19 % of tumor samples also depicted nuclear staining. Importantly, a significant decrease in the overall survival time of grade II and III astrocytoma patients with HO-1 expression was observed. This result was validated at the mRNA level in a cohort of 105 samples. However, no association of HO-1 nuclear localization with patient survival was detected. In vitro experiments aimed at investigating the role of HO-1 in glioma progression showed that HO-1 modulates glioma cell proliferation, but has no effects on cellular migration. In conclusion, our results corroborate the higher frequency of HO-1 protein expression in gliomas than in normal brain, demonstrate that HO-1 is expressed by glial malignant cells, and show an association of HO-1 expression with patients’ shorter survival time.     

肿瘤中TOB1功能相关的调控及其潜在的临床应用价值

TOB1基因编码蛋白是TOB/BTG抗增殖蛋白家族成员之一，目前已在多种肿瘤中发现TOB1表达下调、磷酸化积累和亚细胞分布异常。诸多研究表明TOB1基因的表达既受多种上游转录因子的调控，又能通过多种途径调控其下游靶基因的表达来影响肿瘤细胞的增殖、侵袭、转移和凋亡等，与肿瘤的发生发展密切相关。因此，深入探讨肿瘤中TOB1基因表达调控及相关功能改变在临床中的价值具有重要意义。本文旨在阐述TOB1基因及其相关功能的调控机制在临床肿瘤诊疗和预后评估中的潜在应用。