c-Jun NH2-terminal kinase-induced proteasomal degradation of c-FLIPL/S and Bcl2 sensitize prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine

Tetrandrine, a constituent of Chinese herb Stephania tetrandra, causes cell death in prostate cancer, but the molecular mechanisms leading to apoptosis is not known. Here we demonstrated that tetrandrine selectively inhibits the growth of prostate cancer PC3 and DU145 cells compared to normal prostate epithelial PWR-1E cells. Tetrandrine-induced cell death in prostate cancer cells is caused by reactive oxygen species (ROS)-mediated activation of c-Jun NH₂-terminal kinase (JNK1/2). JNK1/2-mediated proteasomal degradation of c-FLIP_L/S and Bcl₂ proteins are key events in the sensitization of prostate cancer cells to Fas- and mitochondria-mediated apoptosis by tetrandrine. Tetrandrine-induced JNK1/2 activation caused the translocation of Bax to mitochondria by disrupting its association with Bcl₂ which was accompanied by collapse of mitochondrial membrane potential (MMP), cytosolic release of cytochrome c and Smac, and apoptotic cell death. Additionally, tetrandrine-induced JNK1/2 activation increased the phosphorylation of Bcl₂ at Ser70 and facilitated its degradation via the ubiquitin-mediated proteasomal pathway. In parallel, tetrandrine-mediated ROS generation also caused the induction of ligand-independent Fas-mediated apoptosis by activating procaspase-8 and Bid cleavage. Inhibition of procaspase-8 activation attenuated the cleavage of Bid, loss of MMP and caspase-3 activation suggest that tetrandrine-induced Fas-mediated apoptosis is associated with the mitochondrial pathway. Furthermore, most of the signaling effects of tetrandrine on apoptosis were significantly attenuated in the presence of antioxidant N-acetyl-l-cysteine, thereby confirming the involvement of ROS in these events. In conclusion, the results of the present study indicate that tetrandrine-induced apoptosis in prostate cancer cells is initiated by ROS generation and that both intrinsic and extrinsic pathway contributes to cell death.     

Iso-suillin from the mushroom Suillus flavus induces cell cycle arrest and apoptosis in K562 cell line

Iso-suillin, an isomer of suillin that belongs to the prenylphenol class of fungal derivatives, was isolated from petroleum ether extracts of Suillus flavus. The IC₅₀ value of iso-suillin in K562 cells was 0.87 μM, which was lower than the positive control cisplatin (19.33 μM). Iso-suillin-treated K562 cells exhibited an increased rate of apoptosis, mitochondrial membrane potential (MMP) depolarization, and G0/G1 arrest. Western blot analysis revealed that these cells displayed significantly upregulated expression of several apoptosis-related proteins, including cytochrome c, caspase 9, FADD (Fas-associating protein with a novel death domain), caspase 8, caspase 3, and Bax. Moreover, the expression of two anti-apoptosis proteins, NF-κB and Bcl-2, was downregulated. Inhibitors of caspase 9 and caspase 8 protected the K562 cells from apoptosis. Taken together, our results suggest that iso-suillin induces K562 apoptosis through the mitochondrial and death receptor pathways and that iso-suillin may represent a candidate anti-leukemia treatment.     

正常早孕与稽留流产绒毛组织结构中Bax和Bcl-2蛋白表达的对比研究

目的：研究凋亡调控蛋白Bcl-2和Bax在正常早孕与稽留流产绒毛组织结构中的表达及其意义,探讨稽留流产原因。方法选择本院就诊的稽留流产患者和早孕人工流产患者各60例,分为A组、B组。流产后立即留取胚胎绒毛组织送病理。分别应用光镜观察各组绒毛组织细胞形态结构的改变;同时应用免疫组织化学方法和计算机图文分析系统检测Bax、Bcl-2在各组绒毛的表达及细胞凋亡情况。结果稽留流产组绒毛滋养细胞中凋亡指数为（33.32±0.79）%,明显高于对照组B组的（18.90±0.63）%,差异有统计学意义（P〈0.01）。Bax和Bcl-2在两组合体滋养细胞中的阳性率比较显示,稽留流产组中Bax阳性率增高, Bcl-2阳性率下降, Bcl-2/Bax比值降低,差异均有统计学意义（P〈0.01）。结论蜕膜绒毛中Bax阳性率增高和Bcl-2阳性率下降可使绒毛合体滋养细胞凋亡明显增加,并进一步导致稽留流产发生。     

阿胶对围绝经期大鼠卵巢颗粒细胞凋亡及Bcl-2和Bax表达的影响

目的：探讨阿胶对围绝经期大鼠卵巢颗粒细胞凋亡及其相关基因Bcl-2和Bax表达的影响。方法：选用4月龄雌性大鼠为正常对照组,14月龄阴道细胞学表现为动情期延长的雌性大鼠为衰老大鼠模型。模型动物随机分别给阿胶或戊酸雌二醇片治疗。采用原位末端核苷酸标记法（TUNEL）检测卵巢细胞凋亡,免疫组化法检测细胞凋亡相关因子Bcl-2,Bax。结果：阿胶高、中、低剂量组卵巢细胞凋亡阳性表达与模型组比较有显著性差异,同时可使卵巢凋亡基因Blc-2表达增强,促凋亡基因Bax表达减弱,Bcl-2/Bax比例增加。结论：阿胶通过抑制Bax蛋白的表达,上调Bcl-2蛋白表达,抑制卵巢颗粒细胞凋亡,进而改善卵巢功能。     

不同压力高压氧对脑出血大鼠Bcl-2/Bax比值的影响

目的:观察不同压力高压氧(hyperbaric oxygen,HBO)对脑出血(intracerebral hemorrhage,ICH)大鼠出血灶周围组织Bcl-2/Bax比值的影响。方法:应用胶原酶诱导法建立大鼠脑出血模型,将90只雄性脑出血SD大鼠随机分为对照组、高压氧治疗组:1.0ATA组、1.8ATA组、2.0ATA组、2.2ATA组,每组18只,按不同治疗压力于造模后24h进行治疗,1次/d,各组分别于造模成功后第1、3、5天断头取脑,每个时间点各6只。免疫组织化学染色法测定Bcl-2与Bax的表达,对Bcl-2/Bax比值进行统计分析。结果:Bcl-2/Bax比值:第1天时,高压氧治疗组较对照组升高,差异有显著性意义(P0.05),1.8ATA组、2.0ATA组、2.2ATA组较1.0ATA组升高,差异有显著性意义(P0.05),2.2ATA组、2.0ATA组、1.8ATA组依次升高,1.8ATA组、2.0ATA组与2.2ATA组比较差异有显著性意义(P0.05),1.8ATA组与2.0ATA组比较差异无显著性意义(P0.05);第3天时,高压氧治疗组较对照组升高,1.0ATA组与对照组比较差异无显著性意义(P0.05),1.8ATA组、2.0ATA组、2.2ATA组与对照组比较差异有显著性意义(P0.05),2.2ATA组、2.0ATA组、1.8ATA组依次升高,各组之间比较差异均有显著性意义(P0.05);第5天时,高压氧治疗组较对照组升高,差异均有显著性意义(P0.05),2.0ATA组、2.2ATA组低于1.0ATA组,差异无显著性意义(P0.05),1.8ATA组高于1.0ATA组、2.0ATA组、2.2ATA组,差异有显著性意义(P0.05)。结论:HBO治疗可提高出血灶周围脑组织Bcl-2/Bax的比值,抑制出血灶周围组织细胞凋亡,且1.8ATA在提高Bcl-2/Bax的比值上较优。     

糖尿病大鼠脑缺血再灌注后脑组织细胞凋亡与Bax、Bcl-2及P53基因表达

目的观察糖尿病性高血糖大鼠脑缺血再灌注后脑组织细胞凋亡与Bax、Bcl-2和p53表达情况。方法将Wistar大鼠随机分成正常对照组、假手术组、正常血糖脑缺血再灌注组(NIR)和糖尿病性高血糖脑缺血再灌注组(DIR),采用链脲佐菌素腹腔注射制作糖尿病模型、线栓法制作大脑中动脉缺血再灌注模型,应用TUNEL法和免疫组化法分别检测细胞凋亡和Bax、Bcl-2及p53表达。结果与假手术组和正常对照组比较,NIR组凋亡细胞百分率和Bax、Bcl-2、p53表达明显增加(P均<0.01);与NIR组比较,DIR组凋亡细胞百分率和Bax、p53表达明显增加,Bcl-2表达明显降低(P均<0.01)。结论糖尿病性高血糖大鼠脑缺血再灌注后梗死周边区细胞凋亡增加是高血糖加重缺血性脑损伤的机制之一;Bax和p53表达上调、Bcl-2表达下调参与了糖尿病大鼠脑缺血再灌注后细胞凋亡的调控。     

Eholecystokinin octapeptide antagonizes apoptosis in human retinal pigment epithelial cells

Although cholecystokinin octapeptide-8 is important for neurological function, its neuroprotective properties remain unclear. We speculated that cholecystokinin octapeptide-8 can protect human retinal pigment epithelial cells against oxidative injury. In this study, retinal pigment epithelial cells were treated with peroxynitrite to induce oxidative stress. Peroxynitrite triggered apoptosis in these cells, and increased the expression of Fas-associated death domain, Bax, caspase-8 and Bcl-2. These changes were suppressed by treatment with cholecystokinin octapeptide-8. These results suggest that cholecystokinin octapeptide-8 can protect human retinal pigment epithelial cells against apoptosis induced by peroxynitrite.     

雌二醇联合孕激素对卵巢癌细胞凋亡及microRNA-15a表达的影响

目的 探讨雌二醇（E2）联合孕激素（P4）对microRNA-15a （miR-15a）表达的影响。方法 采集手术中切除的卵巢癌组织标本进行细胞培养,分3个处理组：E2组,P4组和雌二醇联合孕激素（E2+P4）组。激素处理后,MTT法检测细胞存活率;流式细胞技术检测细胞凋亡与细胞周期;qRT-PCR法检测Bcl-2,Bax和miR-15a的相对表达量。结果 高浓度（浓度均为10^-4 mol·L^-1）的E2,P4,E2+P4能够降低卵巢癌细胞的存活率,并表现为时间依赖性;低浓度（≤ 10^-8 mol·L^-1） E2能够提高卵巢癌细胞的存活率。与对照组相比,高浓度E2,P4和E2+P4能够增加卵巢癌细胞的凋亡率（P<0.001）,并且E2+P4的作用最明显;低浓度E2能够抑制肿瘤细胞的凋亡（P<0.001）。E2,P4和E2+P4对细胞周期的影响没有统计学差异。高浓度的E2,P4和E2+P4能够下调Bcl-2的表达（P<0.05或P<0.001）,上调Bax的表达（P<0.001）;但是低浓度E2作用却相反。高浓度的E2+P4能够促进miR-15a的表达（P<0.001）。结论 高浓度的E2,P4和E2+P4能够降低细胞的存活率促进细胞凋亡,下调Bcl-2的表达,上调Bax的表达;低浓度E2的作用则相反;高浓度的E2+P4能够促进miR-15a的表达。     

Cadmium induces apoptotic program imbalance and cell cycle inhibitor expression in cultured human astrocytes

Cadmium is a highly neurotoxic heavy metal impairing neurogenesis and induces neurodegenerative disorders. Toxic concentrations of cadmium induce astrocytic apoptosis by depleting intracellular glutathione levels, elevating intracellular calcium levels, altering mitochondria membrane potentials, and activating JNK and PI3K/Akt signaling pathways. Cadmium suppresses cell proliferation in kidney epithelial cells, lung fibroblasts, and primary myelocytes; however, cadmium’s effects on proteins regulating oxidative stress, apoptosis, and cell proliferation in astrocytes are less known. The present study hypothesized that cadmium alters levels of antioxidant enzymes, apoptotic regulator proteins, and cell cycle inhibitor proteins, resulting in apoptosis and cell cycle arrest. Concentrations ≥20 μM cadmium induced apoptosis and led to intracellular changes including DNA fragmentation, reduced mRNA expression of antioxidant enzymes (i.e., catalase and glutathione S transferase-A4), downregulation of B-cell lymphoma 2 (Bcl-2), and upregulation of Bcl-2-associated X protein (Bax). Moreover, cadmium suppressed astrocytic proliferation by inducing S and G2/M phase cell cycle arrest and promoting p53, p21, and p27 expression. In conclusion, this study provides mechanistic insight into cadmium-induced cytotoxicity of astrocytes and highlights potential targets for prevention of cadmium-induced apoptosis and cell cycle arrest.     

米诺环素对脊髓损伤大鼠凋亡机制探索和神经红蛋白表达的影响

目的 探讨米诺环素对脊髓横断损伤大鼠凋亡蛋白 Bcl-2、Bax和 Caspase-3的表达及神经红蛋白 Ngb表 达的影响。方法 36只健康成年雄性 Wistar大鼠随机分为假手术组、脊髓损伤组、米诺环素干预组,每组 12只。假 手术组只暴露脊髓,脊髓损伤组和米诺环素干预组制备胸3~4脊髓节段全横断损伤模型。米诺环素干预组于术前腹 腔注射米诺环素（90 mg/kg）,1次/d,连续5 d,脊髓损伤组和假手术组腹腔注射等体积生理盐水。术后22 d处死所有 大鼠,采用免疫组化染色和 Western blot法检测脊髓组织 Bcl-2、Bax和 Caspase-3蛋白的表达;Hoechst 染色检测凋亡 细胞;免疫荧光染色检测神经红蛋白（Ngb）的表达。结果 与假手术组相比,脊髓损伤组脊髓组织中 Bcl-2表达增 多,Bax和 Caspase-3蛋白的表达增多,凋亡细胞数明显增多,Ngb荧光强度明显增强（均P＜0.05）。与脊髓损伤组相 比,米诺环素干预组Bcl-2表达进一步增高（P＜0.05）,Bax和Caspase-3表达显著降低（P＜0.05）,而凋亡细胞数有所 减少,Ngb的平均荧光强度较其明显增强。结论 米诺环素干预可通过降低 Bax和 Caspase-3的表达,升高 Bcl-2的 表达来抑制细胞凋亡,提高神经红蛋白表达。