Her2、mTOR与胃癌靶向治疗的研究进展

胃癌是世界上癌症相关性死亡的第二大因素,极大地危害人类的健康,尽管手术是治疗胃癌的有效手段,但因早期症状不明显缺乏特异性的初筛指标,大多数患者确诊时已处于中晚期,不可切除,术后胃癌复发转移发生率是60%[1]。全身化疗是不可切除和复发转移胃癌的主要治疗手段,但目前对晚期胃癌尚     

Grb2的抑制在抗肿瘤治疗中的意义

生长因子受体连接蛋白-2（Grb2）是一种广泛表达的衔接蛋白，在多种肿瘤细胞中过度表达，对肿瘤的发生和发展具有重要影响，从而成为肿瘤治疗的靶向位点之一。因此，抑制Grb2在抗肿瘤治疗中具有广泛前景。     

mTOR通路与胃癌的研究进展

哺乳动物雷帕霉素靶蛋白(mTOR)信号转导通路在肿瘤的形成和发展中扮演着非常重要的角色,并参与肿瘤的侵袭和转移。此信号通路于胃癌中高度激活,调控细胞增殖、凋亡、转录、翻译、代谢等细胞生物学过程。本文对mTOR信号传导通路、在胃癌发生发展中的作用及mTOR抑制剂在胃癌治疗中的最新进展进行综述。     

P13K／AKT／mTOR信号通路在乳腺癌Her-2治疗耐药中的作用研究进展

Her-2靶向治疗是Her-2过表达乳腺癌治疗的重要组成部分,但Her-2靶向治疗的耐药严重影响了乳腺癌的治疗。研究证实乳腺癌Her-2靶向治疗出现耐药的过程中有P13K／AKT／mTOR信号通路的激活,因此对P13K／AKT／mTOR信号通路及以P13K／AKT／mTOR信号通路为靶点的药物研究对乳腺癌治疗具有重要意义。     

mTOR通路在肿瘤骨转移中的作用

[摘要] 超过25%的实体瘤患者在晚期都会出现不同程度的骨转移。发生骨转移的肿瘤细胞与骨微环境内细胞相互作用,骨稳态被打破,建立起促进肿瘤生长、加速骨质破坏的恶性循环,进一步促进肿瘤细胞在骨髓腔中浸润,导致转移的级联反应。肿瘤骨转移是一个复杂的过程,大量分子和信号通路参与其中。研究证实,哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin,mTOR）信号通路活性的改变与肿瘤细胞的骨转移以及转移后骨质破坏密切相关。本文从肿瘤细胞的脱落、迁移、黏附和侵入等转移步骤以及骨代谢变化两方面对mTOR信号通路在肿瘤骨转移过程中的作用进行阐述,为肿瘤骨转移的预防和治疗提供新的方向。     

mTOR和VEGF在胃癌中的表达及与预后关系的研究

目的：观察mTOR和VEGF在胃癌中的表达,探讨它们在胃癌发生发展中的意义和对胃癌患者预后的影响。方法：采用组织芯片和免疫组化检测mTOR和VEGF在1072例胃癌中的表达。结果：mTOR和VEGF在胃癌中总表达率分别为50．8％和59．4％。mTOR过度表达与肿瘤部位（贲门、胃底）、腺癌、高／中分化、T1／T2、Ⅰ／Ⅱ期以及PCNA表达有关;VEGF过度表达与年龄（〉60岁）、男性、肿瘤部位（贲门、胃底）、腺癌、高／中分化、肿瘤浸润（T3～T4）、淋巴结转移、PCNA表达以及p53表达有关。mTOR和VEGF共表达率为39．6％。Cox模型结果显示,mTOR和VEGF是胃癌独立的预后因素。结论：mTOR／VEGF信号通路在胃癌中高度激活,mTOR和VEGF的表达是胃癌预后的重要影响因素,可作为胃癌治疗的靶点。     

EPHA2通过增强Akt/mTOR信号通路促进SGC-7901细胞的增殖

背景与目的：EPHA2能够促进胃癌细胞中Cyclin D1的表达及胃癌细胞的细胞周期进程,从而增强胃癌细胞的增殖能力,但EPHA2调控胃癌细胞中Cyclin D1的表达及胃癌细胞的细胞周期进程的分子机制依然不明确。Akt/mTOR信号通路能够通过促进胃癌细胞中Cyclin D1的表达及胃癌细胞的细胞周期进程增强胃癌细胞的增殖能力,且有研究表明EPHA2能够激活Akt/mTOR信号通路。基于此,该研究探讨了Akt/mTOR信号通路在EPHA2促胃癌细胞增殖中的作用。方法：采用蛋白[质]印迹法(Western blot)检测过表达EPHA2和敲低EPHA2表达对SGC-7901细胞中Akt、mTOR和4EBP1磷酸化的影响。使用Akt抑制剂MK2206和mTOR抑制剂RAD001分别处理转染空载体病毒的SGC-7901-NC细胞和过表达EPHA2的SGC-7901-EPHA2细胞,分别通过CCK8、流式细胞术和Western blot检测细胞增殖、细胞周期及周期相关蛋白Cyclin D1的表达。结果：过表达EPHA2增强SGC-7901细胞中Akt、mTOR和4EBP1的磷酸化,敲低EPHA2的表达抑制SGC-7901细胞中Akt、mTOR和4EBP1的磷酸化。MK2206和RAD001处理细胞时,EPHA2过表达对SGC-7901细胞增殖、细胞S期和Cyclin D1表达的促进作用被显著抑制。结论：EPHA2通过增强Akt/mTOR信号通路促进胃癌细胞SGC-7901的增殖能力,提示我们将来针对EPHA2高表达的胃癌患者或许可以采用Akt抑制剂和mTOR抑制剂予以个体化治疗。     

Grb2抑制剂对K562细胞生长增生的影响

目的 探讨针对Grb2-SH3的抑制剂peptidimer-c对K562细胞生长增生的影响.方法 应用N端基团保护的Fmoc化学,固相合成针对Grb2-SH3的二聚肽peptidimer-c,高压液相色谱技术(HPLC)分析肽的纯度,质谱法分析肽的结构,应用pull-down实验,观察peptidimer-c与K562细胞裂解物中Grb2分子的结合.应用锥虫蓝拒染法、WST-1法、克隆形成法观察peptidimer-c对K562细胞生长的抑制.通过克隆形成实验,探讨peptidimer-c与常用的CML治疗药物甲磺酸伊马替尼(商品名:格列卫)、羟基脲及阿糖胞苷联合应用的合并效应.结果 HPLC图谱上只见一样品峰而无其他杂峰.质谱分析显示,所合成的化合物与设计的肽是一致的.pull-down结果显示,peptidimer-c可与K562细胞中的Grb2分子特异性结合.锥虫蓝计数法结果提示,peptidimer-c可明显抑制K562细胞的生长,且在加药后短时间内(3～6h)即有明显作用,其对K562增生的抑制呈浓度依赖型,而非时间依赖型.WST-1检测结果显示,peptidimer-c杀伤K562细胞的半致死剂量为(17±2)μmol/L.几种化合物对K562克隆形成抑制的半致死剂量分别为:peptidimer-c(3.9±0.9)μmol/L,伊马替尼(0.03±0.02)μmol/L,羟基脲(15±7)μmol/L,阿糖胞苷(0.014±0.012)μmol/L.peptidimer-c分别与伊马替尼、阿糖胞苷、羟基脲联合应用时,对K562克隆形成抑制均表现为相加作用或协同作用,其中1.5 μmol/L peptidimer-c与0.05 μmol/L伊马替尼联合应用,表现协同作用,1.5 μmol/L peptidimer-c与0.006 μmol/L阿糖胞苷或0.01 μmol/L阿糖胞苷联用,也显示协同抑制效应.结论 peptidimer-c能有效抑制K562细胞的生长和增生.与其他类型的药物合用,表现为相加或协同效应,可提高抗肿瘤效应.     

Ang2基因表达与胃癌发生发展的关系

观察Ang2基因表达与胃癌发生、进展的关系。方法:应用原位杂交方法检测10例正常粘膜、26例早期胃癌、30例进展期胃癌中Ang2mRNA表达。结果:早期胃癌中Ang2mRNA表达阳性率显著高于正常粘膜的阳性率(P<0.05),进展期胃癌Ang2mRNA表达的阳性率显著高于早期胃癌的阳性率(P<0.01);低分化、未分化胃癌中Ang2mRNA阳性率显著高于高、中分化胃癌(P<0.01)。结论:Ang2基因在胃癌的发生、发展中发挥重要作用,可用作胃癌抗血管治疗的靶标。     

Wnt 和 COX - 2 信号通路在胃癌中的研究现况

研究发现在胃癌高发地区,肠型胃癌的发病比例明显高于非高发地区.Wnt信号通路在细胞发育、增殖、分化、黏附、迁移中起重要作用,同时在胃癌发生、发展过程中起关键角色.近来研究表明在COX-2/PGE2相关的炎症微环境中Wnt信号被激活,并导致胃癌的发生发展,尤其在肠型胃癌.同时Wnt信号通路的激活可促使胃上皮细胞异常增殖,从而使COX-2和Mpges-1表达,促使PGE2增加而导致肿瘤的发生.两者之间可能在胃癌中存在协同作用.研究两者在胃癌中的关系,将为胃癌的诊断、治疗、预后评价提供帮助.     

ErbB receptor tyrosine kinase network inhibition radiosensitizes carcinoma cells

PURPOSE: The expression of epidermal growth factor receptor (EGFR)-CD533, a truncation mutant of the wild-type EGFR, radiosensitizes carcinoma and malignant glioma cell lines. This deletion mutant disrupts EGFR activation and downstream signaling through the formation of inhibitory dimerizations. In this study, the effects of EGFR-CD533 on other ErbB receptor tyrosine kinase (RTK) family members were quantified to better understand the mechanism of EGFR-CD533-mediated radiosensitization. METHODS AND MATERIALS: Breast carcinoma cell lines with different ErbB RTK expression profiles were transduced with EGFR or ErbB2 deletion mutants (EGFR-CD533 and ErbB2-CD572) using an adenoviral vector. ErbB RTK activation, mitogen activated protein kinase (MAPK) and phosphatidylinositol-3-kinase (PI3K)/p70S6K signaling, and clonogenic survival were determined for expression of each deletion mutant. RESULTS: EGFR-CD533 radiosensitizes carcinoma cells with either high EGFR expression (MDA-MB231) or low EGFR expression (T47D) through significant blockade of the ErbB RTK network. Analysis of clonogenic survival demonstrate significant enhancement of the alpha/beta ratios, as determined by the linear-quadratic model. Split-dose survival experiments confirm that EGFR-CD533 reduces the repair of cellular damage after ionizing radiation. CONCLUSION: Expression of EGFR-CD533 inhibits the ErbB RTK network and radiosensitizes carcinoma cells irrespective of the ErbB RTK expression patterns, and ErbB2-CD572 does not radiosensitize cells with low EGFR expression. These studies demonstrate that the mechanism of action for EGFR-CD533-mediated radiosensitization is inhibition of the ErbB RTK network, and is an advantage for radiosensitizing multiple malignant cell types.     

Trastuzumab-induced recruitment of Csk-homologous kinase (CHK) to ErbB2 receptor is associated with ErbB2-Y1248 phosphorylation and ErbB2 degradation to mediate cell growth inhibition

The inhibitory effect of trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of ErbB2, is associated with its ability to induce ErbB2-Y1248 phosphorylation, and the status of phosphorylated ErbB2-Y1248 (ErbB2-pY1248) may correlate with the sensitivity of breast cancers to trastuzumab. The mechanisms of which remain unclear. Here, we show that binding of trastuzumab to ErbB2 activates ErbB2 kinase activity and enhances ErbB2-Y1248 phosphorylation in trastuzumab-sensitive breast cancer cells. This in turn increases the interaction between ErbB2 and non-receptor Csk-homologous kinase (CHK), leading to growth inhibition of breast cancer cells. Overexpression of CHK mimics trastuzumab treatment to mediate ErbB2-Y1248 phosphorylation, Akt downregulation, and growth inhibition of trastuzumab-sensitive breast cancer cells. CHK overexpression combined with trastuzumab exerts an additive effect on cell growth inhibition. We further demonstrate that positive ErbB2-pY1248 staining in ErbB2-positive breast cancer biopsies correlates with the increased trastuzumab response in trastuzumab neoadjuvant settings. Collectively, this study highlights an important role for ErbB2-pY1248 in mediating trastuzumab-induced growth inhibition and trastuzumab-induced interactions between CHK and ErbB2-pY1248 is identified as a novel mechanism of action that mediates the growth inhibition of breast cancer cells. The novel mechanistic insights into trastuzumab action revealed by this study may impact the design of next generation of therapeutic monoclonal antibodies targeting receptor tyrosine kinases, as well as open new avenues to identify novel targets for the treatment of ErbB2-positive cancers.     

E2F1-mediated GINS2 transcriptional activation promotes tumor progression through PI3K/AKT/mTOR pathway in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has high morbidity and mortality rates. It is therefore imperative to study the underlying mechanism of HCC to identify potential prognostic biomarkers and therapeutic targets. Recently, GINS2 has been identified to be a cancer-promoting gene in different cancer types. Nevertheless, the exact mechanism of GINS2 in HCC remains to be elucidated. To systematically explore the significance of GINS2, we first assessed the relative expression of GINS2 in pan-cancers based on data obtained from the HCCDB, TIMER, and TCGA databases. Then, we explored the clinical significance of GINS2 in HCC through Kaplan-Meier method as well as univariate and multivariate cox regression analysis. Additionally, functional enrichment analysis of GINS2 was done through GO, KEGG, PPI network, and immune cell infiltration analyses. Functional experiments were also conducted to investigate the biological significance of GINS2 in HCC cell lines. Our research revealed that GINS2 is involved in HCC progression and highlighted its potential value as a crucial diagnostic and therapeutic target for HCC.     

哺乳动物雷帕霉素靶蛋白及其与胃癌的关系

哺乳动物雷帕霉素靶蛋白（mTOR）信号途径在多种恶性肿瘤中存在异常激活或变异,该途径激活可以调控肿瘤细胞的增殖、存活以及转移能力,进而导致恶性肿瘤发生发展。雷帕霉素及其衍生物通过阻断mTOR通路的信号传递,抑制胃癌细胞生长,促进肿瘤坏死,并能与其他化疗药物产生协同作用,有望为胃癌预防和治疗提供有效的方法。