抑癌基因PTEN对乳腺癌ZR-75-1细胞增殖和转移的抑制作用

背景与目的:研究表明,抑癌基因PTEN不仅能抑制肿瘤细胞的增殖,还能抑制其转移,但其机理还不甚明了.本文研究抑癌基因PTEN对人乳腺癌ZR-75-1细胞增殖和转移的作用.方法:以脂质体介导法分别将野生型PTEN质粒和磷酸酶缺陷的PTEN质粒转染人乳腺癌ZR-75-1细胞,用MTT法测定细胞增殖抑制率:转染后用嘌呤霉素筛选阳性克隆.用Western blot法检测细胞中PTEN蛋白的表达.通过细胞-基质粘附实验和人工重组基底膜侵袭实验,检测细胞粘附抑制率与侵袭抑制率.结果:野生型PTEN质粒转染的ZR-75-1细胞增殖明显被抑制,并伴有部分细胞凋亡;该细胞与未经转染的和磷酸酶缺陷的PTEN质粒转染的ZR-75-1细胞比较.细胞增殖抑制率差异均有统计学意义(42.7% vs.0%及2.7%,P＜0.01),细胞增殖抑制效应随细胞培养时间与质粒浓度的增加而增强.而磷酸酶缺陷的PTEN质粒转染的与未经质粒转染的ZR-75-1细胞比较,细胞增殖抑制率差异无统计学意义(2.7%vs.0%,P＞0.05).在两种PTEN质粒转染的ZR-75-1细胞中PTEN蛋白均明显表达,其中转染野生型PTEN质粒的细胞的粘附抑制率与侵袭抑制率分别达65.7%和70.4%,而转染磷酸酶缺陷的PTEN质粒的ZR-75-1细胞的粘附抑制率与侵袭抑制率分别只有8.8%和6.9%(P＜0.05).结论:具有双特异磷酸酶活性的野生型PTEN基因对ZR-75-1细胞的增殖和转移有一定的抑制作用.     

肾上腺肿瘤组织中Survivin蛋白和PTEN蛋白的表达及其临床意义

背景与目的:肾上腺肿瘤的组织形态学特征比较特殊,仅根据组织病理切片检查难以判断肿瘤的良、恶性程度,给治疗带来很大的困难.本研究旨在探讨Survivin蛋白和PTEN蛋白表达在肾上腺肿瘤的临床诊断及预后评估中的价值.方法:采用免疫组织化学LSAB方法分别对116例肾上腺肿瘤组织标本进行survivin蛋白和FrEN蛋白表达的检测,分为"一"、" "、" "、" "、" "5个等级.采用SPSS13.0软件进行分析.结果:按"一、" "、" "、" "、" "划分,survivin蛋白的表达分别为29例(25.0%)、36例(31.0%)、30例(25.9%)、14例(12.1%)、7例(6.O%);PTEN蛋白的表达分别为8例(6.9%)、17例(14.7%)、30例(25.9%)、33例(28.4%)、28例(24.1%).Survivin蛋白和PTEN蛋白的表达呈明显负相关(r=-0.486,P＜0.05).Survivin蛋白和PTEN蛋白的表达与肾上腺肿瘤患者年龄、性别、肿瘤部位等无明显相关性(P＞0.05).肾上腺皮质腺瘤中Survivin蛋白的表达明显低于肾上腺皮质腺癌(P＜0.05);良性嗜铬细胞瘤Survivin蛋白的表达明显低于恶性嗜铬细胞瘤(P＜0.05).肾上腺皮质腺瘤中:PTEN蛋白的表达明显高于肾上腺皮质腺癌(P＜0.05),良性嗜铬细胞瘤PTEN蛋白的表达明显高于恶性嗜铬细胞瘤(P＜0.05).Survivin蛋白的表达与肾上腺皮质腺癌和恶性嗜铬细胞瘤患者的预后均相关(P＜0.05),Survivin蛋白表达越强,患者预后越差.PTEN蛋白的表达与肾上腺皮质腺癌、恶性嗜铬细胞瘤患者的预后均相关(P＜0.05),PTEN蛋白表达越低,患者预后越差.结论:Survivin蛋白和PTEN蛋白在肾上腺肿瘤组织中的表达与肾上腺肿瘤恶性程度及预后相关.     

内质网应激对Nrf2抗氧化系统调控与高脂诱导的胰岛素抵抗发病机理研究

目的：探讨内质网应激对氧化还原平衡作用及其诱导胰岛素抵抗机制信号机理。方法随机将30只C57BL／6J小鼠分为低脂饲料对照组（LFD组,n＝10）和高脂饲料模型组（HFD组,n＝20）,14周后,经葡萄糖耐量试验（IPGTT）确定胰岛素抵抗模型成功后,HFD 组随机选出10只开始进行4-PBA药物干预（HFD＋PBA 组,n ＝10）,持续1周后检测小鼠葡萄糖耐量（IPGTT）、肌肉和肝脏及相应组织线粒体中丙二醛（ MDA）含量;Western blot检测肌肉和肝脏组织中胰岛素信号、内质网应激信号和Nrf2内源性抗氧化系统相关蛋白的表达。结果4-PBA干预组胰岛素抵抗明显减轻,PTEN蛋白受到抑制从而上调胰岛素信号（ PKB Ser473）;4-PBA干预组MDA水平明显下降,Nrf2系统信号增强;高脂组Keap1蛋白明显上调,而4-PBA干预则减弱这一变化。结论内质网应激造成氧化应激并通过上调 PTEN蛋白和抑制 Nrf2抗氧化系统参与胰岛素抵抗。     

喉鳞状细胞癌中PTEN蛋白表达与微血管密度的相关性

目的 研究喉鳞癌（LSCC）组织中抑癌基因PTEN蛋白（PTEN）的表达与肿瘤微血管密度（MVD）之间的相关性。方法 采用免疫组化SP法检测10例正常喉组织、20例癌旁组织和60例LSCC组织中PTEN基因和MVD的表达情况。结果 PTEN在LSCC、癌旁喉组织及正常组织中阳性表达率分别为70．00％、95．00％、100．00％,差异有显著性（P〈0．01）。LSCC组织中PTEN蛋白表达在TNM分期Ⅰ～Ⅱ期、高中分化癌、无转移、生存率〉3年的患者中表达水平较Ⅲ～Ⅳ期、低分化和有转移、生存率〈3年的患者高,差异有显著性（P〈0．05）。在不同恶性程度、分化程度、预后及有无转移的LSCC组织中,PTEN蛋白表达与MVD呈显著负相关（P〈0．05）。结论 PTEN基因突变和／或缺失可能在LSCC的发生、发展和血管形成中发挥重要作用。PTEN、MVD是反映LSCC生物学行为的重要指标。     

PTEN,Ki-67和CyclinD1在皮肤鳞状细胞癌中的表达及意义

目的探讨PTEN,Ki-67和CyclinD1在皮肤鳞状细胞癌发生发展中的作用及意义。方法采用免疫组化EnVision染色法检测PTEN,Ki-67和CyclinD1在30例皮肤鳞状细胞癌石蜡包埋组织、15例正常皮肤组织中的表达。结果①PTEN在皮肤鳞状细胞癌组织中的表达率较对照组低(P<0.05),与肿瘤分级无相关性(P>0.05);②Ki-67在皮肤鳞状细胞癌组织中的表达率较对照组高(P<0.01),与肿瘤分级相关(P<0.01);③CyclinD1在皮肤鳞状细胞癌组织中的表达率较对照组高(P<0.01),与肿瘤分级相关(P<0.05);④PTEN与Ki-67在皮肤鳞状细胞癌中表达呈负相关(r=-0.411,P<0.05);PTEN与CyclinD1在皮肤鳞状细胞癌中表达呈负相关(r=-0.386,P<0.05);Ki-67和CyclinD1在皮肤鳞状细胞癌中表达呈显著正相关(r=0.623,P<0.01)。结论①PTEN在抑制皮肤鳞状细胞癌的发生发展中存在一定相关性,但与该肿瘤恶性分化程度的关系尚不明确;②Ki-67在皮肤鳞状细胞癌中阳性表达上调,与该肿瘤的分级呈正相关;③CyclinD1在皮肤鳞状细胞癌中阳性表达上调,与该肿瘤的分级呈正相关;④PTEN,CyclinD1与Ki-67三者中两两之间的相互关系反应了抑癌基因与癌基因相互协调、相互促进的关系。     

Ellagic acid,extracted from Sanguisorba officinalis,induces G1 arrest by modulating PTEN activity in B16F10 melanoma cells

In Chinese medicine, herbal medicine is commonly used to treat individuals suffering from many types of diseases. We thus expected that some herbal medicines would contain promising compounds for cancer chemotherapy. Indeed, we found that Sanguisorba officinalis extracts strongly inhibit the growth of B16F10 melanoma cells, and we identified ellagic acid (EA) as the responsible ingredient. B16F10 cells treated with EA exhibited strong G1 arrest accompanied by accumulation of p53, followed by inactivation of AKT. Addition of a PTEN inhibitor, but not a p53 inhibitor, abrogated the EA‐induced AKT inactivation and G1 arrest. The PTEN inhibitor also diminished EA‐induced p53 accumulation. Furthermore, EA apparently increased the protein phosphatase activity of PTEN, as demonstrated by the reduced phosphorylation level of FAK, a protein substrate of PTEN. Furthermore, an in vitro PTEN phosphatase assay on PIP3 showed the direct modulation of PTEN activity by EA. These results suggest that EA functions as an allosteric modulator of PTEN, enhancing its protein phosphatase activity while inhibiting its lipid phosphatase activity. It is notable that a combination of EA and cisplatin, a widely used chemotherapy agent, dramatically enhanced cell death in B16F10 cells, suggesting a promising strategy in chemotherapy.     

PTEN hypermethylation profiles of Chinese Kazakh patients with esophageal squamous cell carcinoma

Aberrant DNA methylation of promoter region CpG islands may serve as an alternative mechanism to genetic defects in the inactivation of tumor suppressor genes (TSGs) in human malignancies. The aim of this study was to examine the promoter methylation status of the PTEN TSG and its association with esophageal squamous cell carcinoma (ESCC) carcinogenesis in a Chinese Kazakh population, which is known to have a relatively high ESCC incidence and mortality. The methylation status of the PTEN promoter region was determined in patients with ESCC (n = 95) and healthy individuals (n = 65) using highly sensitive Sequenom Epityper assays. The methylation level of the PTEN gene was significantly higher in patients with ESCC than in healthy controls. The median methylation level was 10.0% (interquartile range [IQR]: 7.0–11.0%) in patients with ESCC and 6.0% in controls (IQR: 4.0–9.0%; P = 0.001). PTEN methylation levels were higher in male patients with ESCC than in male controls, whereas a trend toward significance was observed between female patients with ESCC and female controls (P = 0.005 and P = 0.086, respectively). The PTEN methylation level was associated with histopathological grade and lymph node metastasis in patients with ESCC (P = 0.002 and P = 0.009, respectively). To our knowledge, this is the first report to show the presence of PTEN promoter CpG hypermethylation in ESCC and its association with tumor metastasis.     

MMP-2及PTEN在人脑星形细胞瘤中的表达及意义

目的探讨基质金属蛋白酶2(MMP-2)及抑癌基因PTEN在人脑星形瘤中的表达及二者与人脑星形细胞瘤侵袭性的关系。方法用免疫组织化学SABC法检测50例人脑星形细胞瘤组织和10例正常人脑组织中的MMP-2和PTEN蛋白的表达,并且分析二者与人脑星形细胞瘤临床病理分级的关系。结果 MMP-2和PTEN在低度恶性星形细胞瘤和高度恶性星形细胞瘤组织中表达差别有统计学意义(p<0.05)。随着星形细胞瘤恶性度增高,MMP-2的表达强度呈上升趋势而PTEN表达强度逐渐下降;Spearman等级相关分析表明人脑星形细胞瘤中MMP-2和PTEN之间呈负相关(Rs=-0.518,P<0.01)。结论 MMP-2和PTEN是人脑星形细胞瘤分化程度和转移的潜在生物学指标,联合检测MMP-2和PTEN更有利于判断星形细胞瘤生物学行为和病理分级。     

PTEN在宫颈癌组织中的表达及对宫颈癌发生、发展的作用

目的探讨第10染色体同源丢失磷酸酶-张力蛋白基因（PTEN）在宫颈癌组织中的表达及对宫颈癌发生、发展的作用。方法选取广东省汕头市中心医院2009年6月～2010年6月宫颈石蜡包埋组织90例,其中正常宫颈组织20例,宫颈癌组织70例;采用SP法检测两类组织中PTEN的表达情况;分析PTEN表达与宫颈癌临床病理指标的关系。结果①PTEN在正常宫颈组织阳性表达率[100%（20/20）]高于在宫颈癌组织中的阳性表达率[70%（49/70）],差异有高度统计学意义（χ2=7.83,P〈0.01）。②PTEN在宫颈癌临床分期（Ⅰ、Ⅱ期）中的表达差异无统计学意义（χ2=1.48,P〉0.05）;PTEN在中高分化和低分化宫颈癌的阳性表达率[71.7%（43/60）,60.0%（6/10）]差异无统计学意义（χ2=0.56,P〉0.05）;PTEN在无淋巴结转移的宫颈癌组织中阳性表达率[73.6%（39/53）]与有淋巴结转移的宫颈癌组织中的阳性表达率[58.8%（10/17）]差异无统计学意义（χ2=1.34,P〉0.05）。结论 PTEN蛋白的表达缺失可能与宫颈癌的发生、发展相关。     

Chinese herbal medicine-derived compounds for cancer therapy: A focus on hepatocellular carcinoma

Ethnopharmacological relevance

Hepatocellular carcinoma (HCC) as the major histological subtype of primary liver cancer remains one of the most common malignancies worldwide. Due to the complicated molecular pathogenesis of HCC, the option for effective systemic treatment is quite limited. There exists a critical need to explore and evaluate possible alternative strategies for effective control of HCC. With a long history of clinical use, Chinese herbal medicine (CHM) is emerging as a noticeable choice for its multi-level, multi-target and coordinated intervention effects against HCC. With the aids of phytochemistry and molecular biological approaches, in the past decades many CHM-derived compounds have been carefully studied through both preclinical and clinical researches and have shown great potential in novel anti-HCC natural product development. The present review aimed at providing the most recent developments on anti-HCC compounds derived from CHM, especially their underlying pharmacological mechanisms.

Materials and methods

A systematic search of anti-HCC compounds from CHM was carried out focusing on literatures published both in English (PubMed, Scopus, Web of Science and Medline) and in Chinese academic databases (Wanfang and CNKI database).

Results

In this review, we tried to give a timely and comprehensive update about the anti-HCC effects and targets of several representative CHM-derived compounds, namely curcumin, resveratrol, silibinin, berberine, quercetin, tanshinone II-A and celastrol. Their mechanisms of anti-HCC behaviors, potential side effects or toxicity and future research directions were discussed.

Conclusion

Herbal compounds derived from CHM are of much significance in devising new drugs and providing unique ideas for the war against HCC. We propose that these breakthrough findings may have important implications for targeted-HCC therapy and modernization of CHM.