BCL-XL异质性表达与复发急性髓性白血病细胞体外生长类型的关系

选择１５例复发急性髓性白血病（ＡＭＬ）患者,研究ＢＣＬ－ＸＬ的异质性表达与复发ＡＭＬ细胞体外生长类型的关系。用白血病祖细胞培养（ＣＦＵ－Ｌ）判断生长类型,ＲＴ－ＰＣＲ方法检测 ＢＣＬ－ＸＬ ｍＲＮＡ的表达丰度。结果：ＣＦＵ－Ｌ检测中,１０例为生长型,其ＢＣＬ－ＸＬ ｍＲＮＡ ９例高表达,１例为低表达;ＣＦＵ－Ｌ检测 ５例为不生长型,ＢＣＬ－ＸＬ ｍＲＮＡ均为低表达（ Ｐ＜０．０１）。在复发ＡＭＬ中,ＢＣＬ－ＸＬ ｍＲＮＡ的高表达与其细胞体外生长类型有关,提示与其细胞的自分泌生长有关,可以作为复发ＡＭＬ再生耐药的一个判断指标。     

New era for myelofibrosis treatment with novel agents beyond Janus kinase-inhibitor monotherapy: Focus on clinical development of BCL-XL/BCL-2 inhibition with navitoclax

Myelofibrosis is a heterogeneous myeloproliferative neoplasm characterized by chronic inflammation, progressive bone marrow failure, and hepatosplenic extramedullary hematopoiesis. Treatments like Janus kinase inhibitor monotherapy (e.g., ruxolitinib) provide significant spleen and symptom relief but demonstrate limited ability to lead to a durable disease modification. There is an urgent unmet medical need for treatments with a novel mechanism of action that can modify the underlying pathophysiology and affect the disease course of myelofibrosis. This review highlights the role of B-cell lymphoma (BCL) protein BCL-extra large (BCL-X_L) in disease pathogenesis and the potential role that navitoclax, a BCL-extra large/BCL-2 inhibitor, may have in myelofibrosis treatment.     

柔红霉素对培养人视网膜色素上皮细胞BAK和BCL-XL表达的影响

目的 观察BAK和BCL-XL在正常培养和经柔红霉素处理后的人视网膜色素上皮(retinal pigment epithelium,RPE)细胞中的表达。方法 人RPE细胞培养液中加入终浓度为200μg·L~(-1)柔红霉素作用12h,更换新鲜培养液继续培养24h后,运用抗BAK和BCL-XL的多克隆抗体进行免疫细胞化学染色,观察2种基因在RPE细胞中表达的变化。结果 BAK和BCL-XL在正常RPE细胞中均存在表达,但前者的染色强度大于后者(P<0.05),2者光密度分别为56.4±5.7和32.4±4.7,经柔红霉素处理后,RPE细胞BAK的染色强度增加(P<0.05),而BCL-XL的染色强度不变(P>0.05),其光密度值分别为79.2±6.5和34.7±3.9。结论 BAK和BCL-XL在人RPE细胞中存在表达。柔红霉素可以促进BAK的表达,这可能是其诱导RPE细胞凋亡的机理之一。     

姜黄素抑制k562细胞生长并诱导凋亡机制的研究

目的探讨姜黄素抑制人类红白血病细胞（k562细胞）生长并诱导凋亡的机制及其对细胞凋亡相关基因BCL-XL和BAK表达的影响。方法把不同浓度姜黄素加入k562细胞,流式细胞仪检测其凋亡及其细胞周期的变化,RT-PCR方法检测BCL-XL和BAK mRNA的表达,免疫组化方法检测BCL—XL和BAK蛋白的表达。结果姜黄素可以对k562细胞有较明显的增殖抑制作用,且呈剂量依赖,流式细胞术结果显示姜黄素浓度在100μmol／L时作用24、48h后,凋亡率高于对照组（P〈0．05）;随着姜黄素浓度增加,作用于k562细胞后可以使其倍增时间明显延长,G1期细胞增多,S期细胞减少;RT-PCR结果显示姜黄素能下调k562细胞BCL-XL表达,上调BAK mRNA的表达（P〈0．05）,免疫组化法发现姜黄素可以降低BCL-XL表达,升高BAK的表达（P〈0．05）。结论姜黄素对k562细胞的生长有较明显的抑制作用,且呈一定时间与剂量关系,并促进k562细胞凋亡,可能和下调BCL—XL的表达和上调BAK的表达相关。     

Induction of the Intrinsic Apoptotic Pathway by 3-Deazaadenosine Is Mediated by BAX Activation in HL-60 Cells

3-Deazaadenosine (DZA), a potent inhibitor of S-adenosylhomocysteine hydrolase, was previously proposed to induce intrinsic apoptosis in human leukemic cells. In the present study, we analyzed the mechanism underlying the DZA-induced intrinsic apoptotic pathway. DZA activated typical caspase-dependent apoptosis in HL-60 cells, as demonstrated by an accumulation of hypo-diploidic cells, the processing of multiple procaspases and an inhibitory effect of z-VAD-Fmk on this cell death. During DZA-induced apoptosis, cytochrome c (cyt c) was released into the cytosol. This was neither prevented by z-VAD-Fmk and nor was it associated with the dissipation of mitochondrial membrane potential (ΔΨ_m). Prior to the release of cyt c, BAX was translocated from the cytosol to mitochondria and underwent oligomerization. Finally, the overexpression of BCL-XL protected HL-60 cells from apoptosis by blocking both the cyt c release and BAX oligomerization. Collectively, these findings suggest that DZA may activate intrinsic apoptosis by stimulating BAX activation and thereby the release of cyt c.     

BH3 profiling and a toolkit of BH3-mimetic drugs predict anti-apoptotic dependence of cancer cells

Background:

Anti-apoptotic BCL-2 family members antagonise apoptosis by sequestering their pro-apoptotic counterparts. The balance between the different BCL-2 family members forms the basis of BH3 profiling, a peptide-based technique used to predict chemosensitivity of cancer cells. Recent identification of cell-permeable, selective inhibitors of BCL-2, BCL-X_L and MCL-1, further facilitates the determination of the BCL-2 family dependency of cancer cells.

Methods:

We use BH3 profiling in combination with cell death analyses using a chemical inhibitor toolkit to assess chemosensitivity of cancer cells.

Results:

Both BH3 profiling and the inhibitor toolkit effectively predict chemosensitivity of cells addicted to a single anti-apoptotic protein but a combination of both techniques is more instructive when cell survival depends on more than one anti-apoptotic protein.

Conclusions:

The inhibitor toolkit provides a rapid, inexpensive and simple means to assess the chemosensitivity of tumour cells and in conjunction with BH3 profiling offers much potential in personalising cancer therapy.     

Apogossypolone诱导骨髓瘤细胞凋亡及其机制研究

本研究探讨棉酚衍生物apogossypolone（ApoG2）对多发性骨髓瘤细胞系的抑制增殖、诱导凋亡的作用及其作用机制。应用台盼蓝染色、Hoechst 33258染色、透射电子显微镜检、DNA凝胶电泳法、流式细胞仪分析细胞DNA含量等来判断ApoG2对多发性骨髓瘤细胞的抑制增殖和诱导凋亡作用。以caspase-3、caspase-9以及BCL-2、BCL—XL分析ApoG2诱导骨髓瘤细胞凋亡的可能机制。结果表明：ApoG2对多发性骨髓瘤细胞增殖具有明显的抑制作用,IC50值在U266细胞和Wusl细胞（48小时）分别为0．1、0．2μmol／L。ApoG2可以诱导骨髓瘤细胞凋亡且呈时间和剂量依赖性。ApoG2可以使骨髓瘤细胞周期停止在G2期,U266细胞G2期比例从9．7％增至19．6％。Wusl细胞从9．8％增至31．7％。ApoG2能导致U266、Wusl细胞caspase-9、caspase-3活性增高。U266细胞和Wusl细胞经ApoG2 25μmoL／L作用24小时后,BCL—XL表达分别下降（7．3±1．4）％和（11．2±6．2）％,Wusl细胞BCL-2表达下降84．4±3．4％。结论：ApoG2对多发性骨髓瘤细胞具有抑制增殖和诱导凋亡作用,其作用机制可能和下调BCL-2／BCL—XL表达以及影响细胞周期有关。     

环孢霉素A对损伤大鼠脊髓BCL-XL表达的影响

目的探讨环孢霉素A（CSA）对全横断损伤大鼠脊髓BCL-XL表达的影响.方法将成年SD大鼠分脊髓T9全横断（SCT）组和SCT后给予CSA处理组（每组13只动物）,CSA处理后7 d处死动物.其中每组5只用免疫组化染色确定BCL-XL在脊髓的定位分布.另8只动物用RT-PCR技术确定BCL-XL在损伤脊髓的表达变化.结果与SCT组比较（0.74±0.08）,CSA处理导致BCL-XL在损伤脊髓的表达（0.85±0.11）明显上调（P〈0.05）;免疫组化染色显示BCL-XL主要分布在脊髓灰质神经元.结论 CSA能有效上调损伤脊髓BCL-XL的表达,提示CSA发挥免疫抑制作用可能与BCL-XL的调节有关.