蟾蜍灵诱导HL-60细胞凋亡过程中对Bcl-2、Survivin、Smac/DIABLO表达的影响

目的 研究蟾蜍灵在诱导HL-60细胞凋亡过程中，对线粒体凋亡途径相关基因Bcl-2、Bax、Survivin及Smac／DIABLO表达的影响。方法 采用锥虫蓝拒染法检测细胞存活情况，细胞形态学观察及流式细胞术检测细胞凋亡，Western blot分析Bcl-2、Bax、Smac／DIABLO、Survivin及caspase-3蛋白表达，RT-PCR检测SurvivinmRNA表达。结果 蟾蜍灵抑制HL-60细胞增殖，24，48及72h的，IC50值分别为25．8，8．0及2．1nmol/L。蟾蜍灵大于50．0nmol/L时可明显诱导HL-60细胞凋亡。50．0nmol／L蟾蜍灵作用6，12，24及48h，Bcl-2蛋白表达分别下调至作用前的88．6％，53．3％，19．2％及9．5％，而Bax蛋白表达无明显变化，Bcl-2／Bax比值由2．0分别降至1．7，1．1，0．4及0．2。Survivin蛋白表达分别下调至作用前的75．2％，54．8％，37．5％及20．3％；Survivin mRNA表达在作用6，12和24h后分别下调至作用前的85．7％，39．4％和12．5％，在作用48h后几乎检测不到。50．0nmol／L蟾蜍灵作用12，24及48h，线粒体部分的Smac／DIABLO蛋白表达分别下调至作用前的77．5％，21．2％及15．3％，而胞浆部分的Smac／DIABLO蛋白表达分别上调至作用前的1．4，2．0．及3．5倍。蟾蜍灵作用8～48h可检测到caspase-3的活化亚基。结论 蟾蜍灵诱导的HL-60细胞凋亡与Bcl-2及Survivin表达下调、线粒体释放Smac／DIABLO及caspase-3活化有关。     

低剂量X线照射对人骨髓间充质干细胞的生物学效应

本研究探讨低剂量X线辐射对间充质干细胞(MSC)功能的影响。获取正常人骨髓MSC,接受低剂量X线辐射后,用MTT方法检测照射后1-7天的吸光度,绘制生长曲线;RT-PCR法检测MSC的survivin mRNA表达,用MSC的单细胞凝胶电泳检测DNA损伤。结果表明:接受低剂量X线辐射后,MSC的增殖能力明显增加,MSC的DNA损伤程度似呈剂量依赖模式,MSC的survivin基因表达升高。结论:低于20 cGy的辐射对正常人骨髓MSC产生survivin mRNA表达增高的效应,至于高表达survivin是否有抵抗辐射的效应,仍有待进一步探讨。     

Survivin在造血系统肿瘤中的研究进展

Survivin是一种新的凋亡抑制蛋白(inhibitor of apoptosisprotein，IAP)，具有细胞周期调控和凋亡抑制双重功能。在多种造血系统肿瘤组织中高表达，与诊断、预后和耐药密切相关。利用survivin致敏的树突状细胞疫苗、survivin反义核酸及Survivin阴性突变体可有效抑制肿瘤细胞生长，为采用生物学策略治疗造血系统肿瘤开辟了新途径.本综述重点阐述了survivin在造血系统肿瘤中的表达，survivin与造血系统肿瘤预后和耐药的关系及survivin在造血系统肿瘤治疗中的应用。     

YM155 sensitizes triple‐negative breast cancer to membrane‐bound TRAIL through p38 MAPK‐ and CHOP‐mediated DR5 upregulation

Because available treatments have limited efficacy in triple‐negative breast cancer (TNBC), the identification of new therapeutic strategies to improve patients' outcome is urgently needed. In our study, we investigated the effects of the administration of the small molecule selective survivin suppressant YM155, alone or in association with CD34+ cells transduced with a replication‐deficient adenovirus encoding the human tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) gene (CD34‐TRAIL+ cells), in three TNBC cell models. YM155 exposure significantly impaired TNBC cell growth and selectively modulated survivin expression at both mRNA and protein level. In addition, co‐culturing YM155‐treated TNBC cells with CD34‐TRAIL+ cells resulted in markedly increased cytotoxic effect and apoptotic response in comparison with single treatments. Such a chemosensitizing effect was observed only in TNBC cells inherently expressing DR5 and relied on the ability of YM155 to upregulate DR5 expression through a p38 MAPK‐ and CHOP‐dependent mechanism. YM155/CD34‐TRAIL+ combination also showed a significant inhibitory effect on the growth of DR5‐expressing TNBC cells following xenotransplantation into NOD/SCID mice, in the absence of toxicity. Overall, our data (i) provide, for the first time, evidence that YM155 sensitizes TNBC cells to CD34‐TRAIL+ cells‐induced apoptosis by a mechanism involving the downregulation of survivin and the simultaneous p38 MAPK‐ and CHOP‐mediated upregulation of DR5, and (ii) suggest the combination of YM155 with TRAIL‐armed CD34+ progenitor cells as a promising therapeutic option for patients with TNBC expressing DR5.     

Anti-tumor activity of selective inhibitors of XPO1/CRM1-mediated nuclear export in diffuse malignant peritoneal mesothelioma: the role of survivin

Survivin, which is highly expressed and promotes cell survival in diffuse malignant peritoneal mesothelioma (DMPM), exclusively relies on exportin 1 (XPO1/CRM1) to be shuttled into the cytoplasm and perform its anti-apoptotic function. Here, we explored the efficacy of Selective Inhibitors of Nuclear Export (SINE), KPT-251, KPT-276 and the orally available, clinical stage KPT-330 (selinexor), in DMPM preclinical models. Exposure to SINE induced dose-dependent inhibition of cell growth, cell cycle arrest at G1-phase and caspase-dependent apoptosis, which were consequent to a decrease of XPO1/CRM1 protein levels and the concomitant nuclear accumulation of its cargo proteins p53 and CDKN1a. Cell exposure to SINE led to a time-dependent reduction of cytoplasmic survivin levels. In addition, after an initial accumulation, the nuclear protein abundance progressively decreased, as a consequence of an enhanced ubiquitination and proteasome-dependent degradation. SINE and the survivin inhibitor YM155 synergistically cooperated in reducing DMPM cell proliferation. Most importantly, orally administered SINE caused a significant anti-tumor effect in subcutaneous and orthotopic DMPM xenografts without appreciable toxicity. Overall, we have demonstrated a marked efficacy of SINE in DMPM preclinical models that may relay on the interference with survivin intracellular distribution and function. Our study suggests SINE-mediated XPO1/CRM1 inhibition as a novel therapeutic option for DMPM.     

Survivin在中线T细胞淋巴瘤中的表达及其与EB病毒感染的关系

为了探讨凋亡抑制基因存活蛋白（survivin）在中线T细胞淋巴瘤（midline T-cell lymphoma,MTL）中的表达及其与EB病毒（Epstin-Barr virus,EBV）感染的关系,应用免疫组织化学方法检测石蜡切片中存活蛋白和EBV潜伏膜蛋白（latent membrane protein,LMP-1）的表达,采用原位分子杂交技术检测EBV编码的RNA（EBV-encoded RNA,EBER1/2）.结果表明：41例MTL中26例存活蛋白阳性表达（63.42%）,而在10例反应性增生淋巴组织中均未检测出存活蛋白表达;存活蛋白在低度恶性MTL中的阳性表达率为12.50%,在中-高度恶性MTL中的阳性表达率为75.76%,两组之间的差异具有显著性的意义（x^2=8.55,P＜0.01）;EBER 1/2阳性率为70.73%,LMP-1阳性率为41.46%,EBV阳性组与EBV阴性组之间存活蛋白的表达差异无显著性意义（P＞0.05）.结论：MTL组织中存活蛋白表达上调,存活蛋白表达阳性率与MTL的恶性程度有关,存活蛋白基因可能通过肿瘤细胞凋亡的抑制参与MTL的发生发展,但未发现存活蛋白表达与EBV感染之间有明显相关性.