藏红花素诱导人胶质瘤U251细胞内质网应激性凋亡的研究

目的:研究藏红花素对人胶质瘤U251细胞的促凋亡作用和可能的机制。方法:不同浓度藏红花素处理U251细胞后,MTT法检测细胞活力,TUNEL染色观察细胞凋亡情况。结果:①藏红花素显著抑制U251细胞的增殖,并诱导其发生凋亡。②藏红花素增加了U251细胞胞浆内钙离子的含量,并上调了内质网分子伴侣GRP78的表达。③藏红花素处理后的U251细胞内质网相关凋亡分子CHOP,Caspase-4,JNK活性明显增高。结论:藏红花素通过诱导内质网应激性凋亡抑制人胶质瘤U251细胞的增殖。     

藏红花素诱导人胶质瘤U251细胞内质网应激性凋亡的研究

目的：研究藏红花素对人胶质瘤U251细胞的促凋亡作用和可能的机制。方法：不同浓度藏红花素处理U251细胞后,MTT法检测细胞活力,TUNEL染色观察细胞凋亡情况。结果：①藏红花素显著抑制U251细胞的增殖,并诱导其发生凋亡。②藏红花素增加了U251细胞胞浆内钙离子的含量,并上调了内质网分子伴侣GRP78的表达。③藏红花素处理后的U251细胞内质网相关凋亡分子CHOP,Caspase-4,JNK活性明显增高。结论：藏红花素通过诱导内质网应激性凋亡抑制人胶质瘤U251细胞的增殖。     

Combination Treatment with Resveratrol and Sulforaphane Induces Apoptosis in Human U251 Glioma Cells

Resveratrol is a naturally occurring polyphenolic compound highly enriched in grapes, peanuts, red wine, and a variety of food sources. Sulforaphane belongs to the family of isothiocyanates and is highly enriched in cruciferous vegetables. Our previous study showed that resveratrol, when used at high concentrations, inhibited cell proliferation, caused the cell cycle arrest and induced apoptotic cell death in glioma cells. In the current study, we tested the effect of combination treatment with resveratrol and sulforaphane, when both were used at low concentrations, on cell proliferation, migration and death in human U251 glioma cells. Our study shows that combination treatment with resveratrol and sulforaphane inhibits cell proliferation and migration, reduces cell viability, induces lactate dehydrogenase release, decreases pro-survival Akt phosphorylation and increases caspase-3 activation. The use of combination of bioactive food components, such as resveratrol and sulforaphane, may be a viable approach for the treatment of glioma.     

土贝母苷甲经miR-21/ PDCD4 途径诱导胶质瘤U251细胞凋亡

目的:研究土贝母苷甲(TBMS I)对胶质瘤U251细胞的抗肿瘤作用以及探究土贝母苷甲对miR-21及其靶基因PDCD4基因表达的影响。方法:U251细胞在体外进行培养,四甲基偶氮唑盐(MTT)法检测不同浓度的土贝母苷甲对细胞增殖的影响;Hoechst33258染色观察细胞核形态的变化;实时荧光定量PCR检测miR-21和PDCD4基因的表达情况;Western blot检测PDCD4蛋白的表达情况。结果:土贝母苷甲能够显著抑制U251细胞的增殖,其抑制作用呈剂量和时间依赖性。Hoechst33258染色观察到土贝母苷甲处理组细胞的细胞核形态表现出典型的凋亡特征。PCR结果显示:随着土贝母苷甲浓度增加,miR-21的表达逐渐降低(P0.05),PDCD4基因表达显著增加(P0.05)。Western blot结果提示:与阴性对照组相比,15、30μg/mL土贝母苷甲显著上调了PDCD4蛋白的表达(P0.05)。结论:土贝母苷甲能够显著抑制人胶质瘤U251细胞的增殖并诱导细胞发生凋亡,其机制可能与下调miR-21的表达和上调PDCD4的表达有关。     

线粒体移植增强人神经胶质瘤U87细胞的辐射敏感性

线粒体移植( mitochondrial transplantation)是从患者正常组织分离线粒体然后注入线粒体损伤或缺失的部位,使损伤细胞获得救治、器官功能得以恢复的全新干预技术。本研究重点探讨线粒体移植对人神经胶质瘤细胞(U87)辐射敏感性的影响。提取人星形胶质细胞(human astrocytes, HA)的线粒体,用荧光探针Mito-Tracker Red进行标记后再与U87细胞共培养,激光共聚焦显微镜观察发现,Mito-Tracker Red的红色荧光大量出现在U87细胞内;随后对进入细胞内的游离线粒体荧光强度进行定量分析,游离线粒体和U87细胞共培养12 h时,单细胞内荧光强度由本底值0.08上升至1.83,表明游离线粒体可以通过共培养方式进入U87细胞内。随后给予U87细胞X射线辐照,Western印迹结果显示,联合组与单独辐照组相比,Cyto-C和Bax的表达量分别由179.5%和198.5%升高至251.72%和256.10%,Bcl-2的表达量由57.17%降低至22.23%;使用Annexin V/PI双染法检测到联合组U87细胞凋亡量相比单独辐照组的3.1%和23.5%上升至19.2%和43.8%;RT-CES检测结果表明,96 h内联合组U87细胞生长曲线被抑制;联合组克隆形成率相对单独辐照组的53%下降至29.3%。鬼笔环肽染色发现,线粒体移植组细胞表面丝状伪足相比对照组明显减少。本研究提示,线粒体移植能够促进辐射诱导的肿瘤细胞凋亡,对U87细胞具有辐射增敏作用,其作用机制与重新激活线粒体凋亡通路、降低肿瘤恶性程度有关。     

海星皂甙1对人胶质瘤U87细胞抗增殖作用的研究

目的:海星皂甙是一类从海星中分离、萃取出来的甾体苷类,被认为是海星体内毒素的主要成分.研究表明海星皂甙及其化学衍生物具有多种药理学活性,包括抗菌、抗病毒、抗肿瘤、抑制真菌活性等.本实验旨在研究海星皂甙1对人胶质瘤U87细胞的抗增殖作用和可能的机制.方法:不同浓度海星皂甙l处理人胶质瘤U87细胞后,采用MTT法检测细胞活力,TUNEL染色观察细胞凋亡情况,Westernblot检测内质网应激相关凋亡分子的活性.结果:①海星皂甙1显著抑制U87细胞的增殖,呈时间与剂量依赖性.②海星皂甙1诱导U87细胞发生凋亡.③海星皂甙1处理后U87细胞内质网相关凋亡分子活性明显增高.结论:海星皂甙1通过诱导细胞凋亡抑制人胶质瘤U87细胞的增殖,这种抗增殖作用可能是通过激活内质网应激相关凋亡分子实现的.     

Non-Structural Protein 5 of Zika Virus Interacts with p53 in Human Neural Progenitor Cells and Induces p53-Mediated Apoptosis

Virologica Sinica - Zika virus (ZIKV) infection could disrupt neurogenesis and cause microcephaly in neonates by targeting neural progenitor cells (NPCs). The tumor suppressor p53-mediated cell...     

Ciglitazone Induces Caspase-Independent Apoptosis through Down-Regulation of XIAP and Survivin in Human Glioma Cells

Induction of apoptosis may be a promising therapeutic approach in cancer therapy. Peroxisome proliferator-activated receptor-γ (PPARγ) agonists induce apoptosis in various cancer cells. However, the molecular mechanism remains to be defined. The present study was undertaken to determine the precise mechanism of cell death induced by ciglitazone, a synthetic PPARγ agonist, in A172 human glioma cells. Ciglitazone resulted in a concentration- and time-dependent apoptotic cell death. Similar results were obtained with troglitazone, another synthetic PPARγ agonist. Ciglitazone induced reactive oxygen species (ROS) generation and ciglitazone-induced cell death was prevented by the antioxidant N-acetylcysteine, suggesting an important role of ROS generation in the ciglitazone-induced cell death. The cell death induced by ciglitazone was inhibited by the PPARγ antagonist GW9662. Although ciglitazone treatment caused a transient activation of extracellular signal-regulated kinase (ERK) and p38, the ciglitazone-induced cell death was not affected by inhibitors of these kinses. Ciglitazone caused a loss of mitochondrial membrane potential and its effect was prevented by N-acetylcysteine and GW9662. The specific inhibitor of caspases-3 DEVD-CHO and the general caspase inhibitor z-DEVD-FMK did not exert the protective effect against the ciglitazone-induced cell death and caspase-3 activity also was not altered by ciglitazone. The ciglitazone-induced cell death was accompanied by down-regulation of XIAP and Survivin, but not by release of apoptosis-inducing factor. Taken together, these findings suggest that down-regulation of XIAP and Survivin may play an active role in mediating a caspase-independent and -PPARγ-dependent cell death induced by ciglitazone in A172 human glioma cells. These data may provide a novel insight into potential therapeutic strategies for treatment of glioblastoma.     

丹酚酸B通过抑制线粒体功能增加胶质瘤细胞的放疗敏感性

目的:研究药用植物丹参的根茎提取成分丹酚酸B对人胶质瘤U251细胞的放疗增敏作用,并探讨其可能的分子机制。方法:使用1μM浓度的丹酚酸B处理胶质瘤U251细胞,并用等量PBS建立对照组,使用射线照射建立放射治疗模型。MTT法检测细胞活力;流式细胞术检测细胞凋亡;荧光染色检测活性氧ROS含量及线粒体肿胀程度。结果:丹酚酸B能够显著降低射线照射后U251细胞活力,并增加其凋亡(P0.05)。丹酚酸B能够显著增加射线照射后U251细胞活性氧ROS的产生,并增加线粒体的肿胀程度(P0.05)。结论:丹酚酸B能够通过诱导内源性凋亡增加胶质瘤细胞的放疗敏感性,这种作用可能是通过抑制线粒体功能而实现的。     

Costunolide Induces Apoptosis through Generation of ROS and Activation of P53 in Human Esophageal Cancer Eca‐109 Cells

Costunolide is a sesquiterpene lactone, which possesses potent anti‐cancer properties. However, there is little report about its effects on esophageal cancer. In our study, we investigated the effects of costunolide on the cell viability, cell cycle, and apoptosis in human esophageal cancer Eca‐109 cells. It was found that costunolide inhibited the growth of Eca‐109 cells in a dose‐dependent manner, which was associated with the loss of mitochondrial membrane potential (Δψ_m) and the production of ROS. Costunolide induced apoptosis of Eca‐109 cells as well as cell cycle arrest in G1/S phase by upregulation of P53 and P21. Costunolide triggered apoptosis in esophageal cancer cells via the upregulation of Bax, downregulation of Bcl‐2, and significant activation of caspase‐3 and poly ADP‐ribose polymerase. These effects were markedly abrogated when cells were pretreated with N‐acetylcysteine, a specific reactive oxygen specie inhibitor. These results suggest that costunolide is a potential candidate for the treatment of esophageal cancer.     

NPRL-Z-1, as a New Topoisomerase II Poison,Induces Cell Apoptosis and ROS Generation in Human Renal Carcinoma Cells

NPRL-Z-1 is a 4β-[(4″-benzamido)-amino]-4′-O-demethyl-epipodophyllotoxin derivative. Previous reports have shown that NPRL-Z-1 possesses anticancer activity. Here NPRL-Z-1 displayed cytotoxic effects against four human cancer cell lines (HCT 116, A549, ACHN, and A498) and exhibited potent activity in A498 human renal carcinoma cells, with an IC₅₀ value of 2.38 µM via the MTT assay. We also found that NPRL-Z-1 induced cell cycle arrest in G1-phase and detected DNA double-strand breaks in A498 cells. NPRL-Z-1 induced ataxia telangiectasia-mutated (ATM) protein kinase phosphorylation at serine 1981, leading to the activation of DNA damage signaling pathways, including Chk2, histone H2AX, and p53/p21. By ICE assay, the data suggested that NPRL-Z-1 acted on and stabilized the topoisomerase II (TOP2)–DNA complex, leading to TOP2cc formation. NPRL-Z-1-induced DNA damage signaling and apoptotic death was also reversed by TOP2α or TOP2β knockdown. In addition, NPRL-Z-1 inhibited the Akt signaling pathway and induced reactive oxygen species (ROS) generation. These results demonstrated that NPRL-Z-1 appeared to be a novel TOP2 poison and ROS generator. Thus, NPRL-Z-1 may present a significant potential anticancer candidate against renal carcinoma.     

Triptolide Induces Growth Inhibition and Apoptosis of Human Laryngocarcinoma Cells by Enhancing p53 Activities and Suppressing E6-Mediated p53 Degradation

Triptolide, an active compound extracted from Chinese herb Leigongteng (Tripterygium wilfordii Hook F.), shows a broad-spectrum of anticancer activity through its cytotoxicity. However, the efficacy of triptolide on laryngocarcinoma rarely been evaluated, and the mechanism by which triptolide-induced cellular apoptosis is still not well understood. In this study, we found that triptolide significantly inhibited the laryngocarcinoma HEp-2 cells proliferation, migration and survivability. Triptolide induces HEp-2 cell cycle arrest at the G1 phase and apoptosis through intrinsic and extrinsic pathways since both caspase-8 and -9 are activated. Moreover, triptolide enhances p53 expression by increasing its stability via down-regulation of E6 and E6AP. Increased p53 transactivates down-stream target genes to initiate apoptosis. In addition, we found that short time treatment with triptolide induced DNA damage, which was consistent with the increase in p53. Furthermore, the cytotoxicity of triptolide is decreased by p53 knockdown or use of caspases inhibitor. In conclusion, our results demonstrated that triptolide inhibits cell proliferation and induces apoptosis in laryngocarcinoma cells by enhancing p53 expression and activating p53 functions through induction of DNA damage and suppression of E6 mediated p53 degradation. These studies indicate that triptolide is a potential anti-laryngocarcinoma drug.     

Ceramide Induces Non-Apoptotic Cell Death in Human Glioma Cells

Ceramide causes either apoptosis or non-apoptotic cell death depending on model system and experimental conditions. The present study was undertaken to examine the effect of ceramide on cell viability and its molecular events leading to cell death in A172 human glioma cells. Ceramide induced cell death in a dose-dependent manner and the cell death was dependent on generation of reactive oxygen species and lipid peroxidation. TUNEL assay, Hoechst 33258 staining, and flow cytometric analysis did not show typical apoptotic morphological features. Ceramide caused phosphorylation of extracellular signal-regulated kinase (ERK) and p38, but the cell death was not affected by inhibitors of MAPK subfamilies. Ceramide caused ATP depletion without loss of mitochondrial membrane potential. Ceramide did not induce caspase activation and ceramide-induced cell death was also not altered by inhibitors of caspase activation. Transfection of dominant inhibitory mutant of IκBα (S32A/36A) and pretreatment of pyrrolidinedithiocarbamate, an inhibitor of NF-κB, enhanced ceramide-induced cell death. These results indicate that ceramide causes non-apoptotic, caspase-independent cell death by inducing reactive oxygen species generation in A172 human glioma cells. NF-κB is involved in the regulation of ceramide-induced cell death in human glioma cells.     

Lipocalin-2 Induces Apoptosis in Human Hepatocellular Carcinoma Cells Through Activation of Mitochondria Pathways

Lipocalin 2 (LCN2) is a secreted, iron-binding glycoprotein that is abnormally expressed in some malignant human cancers. However, the roles of LCN2 in hepatocellular carcinoma (HCC) cells are unknown. In this study, we suggested the LCN2 and LCN2R were weak detected in the HCC cell lines, LCN2 and LCN2R were found to be down-regulated in tumor tissues in 16 HCC patients. MTT, DAPI, TUNEL, and flow cytometry analyses revealed that LCN2 overexpression dramatically inhibited cell viability, induced apoptosis features of cell-cycle arrest in sub-G1 phase, in DNA fragmentation, and in condensation of chromatin in Huh-7 and SK-Hep-1 cells. Western blots were used to detect the activation of caspase, pro-apoptosis, and anti-apoptosis protein expression in overexpress-LCN2 HCC cells. LCN2-induced apoptosis was characterized by cleavage of caspase-9, -8, -3, and PARP protein, and a reduction in the mitochondrial membrane potential (MMP). Furthermore, LCN2 also enhanced the down-regulated Bcl-2 and up-regulated the expression of Bax. In addition, our experiments with caspase inhibitors LEHD-FMK and IETD-FMK prevent LCN2-induced apoptosis. We also demonstrated that treatment of overexpress-LCN2 HCC cells with the LCN2 neutralized antibody also significantly attenuated LCN2-induced cell apoptosis. These findings indicate that LCN2 overexpression can effectively induce apoptosis of HCC cells and may be used as a potent therapy against human HCC.     

Sodium Selenite-Induced Apoptosis Mediated by ROS Attack in Human Osteosarcoma U2OS Cells

Sodium selenite (Na₂SeO₃, SSE) is an inorganic Se compound that is widely used in cancer chemoprevention studies. SSE has been shown to have anti-proliferative effects on several types of human cancer cells, but its effect on osteosarcoma cells has thus far not been reported. In this study, the cytotoxic effect of SSE on osteosarcoma cells U2OS was investigated in vitro and found to be higher than on comparable non-cancer cell lines 293 and L6. Treatment with SSE decreased cell growth in a dose- and time-dependent manner and altered cellular morphology. SSE also inhibited cell viability by inducing apoptosis, as evidenced by the formation of apoptotic bodies, generation of reactive oxygen species (ROS), and accumulation of cells during the advanced phase of apoptosis. SSE-induced apoptosis correlated with the activation of CASP 3, downregulation of BCL-2, and upregulation of P53 and PTEN in U2OS cells. These results indicated that SSE induces apoptosis in U2OS cells mainly through an ROS-mediated caspase pathway. This is the first report to show a possible mechanism of the anti-proliferative effect of SSE for the prevention of osteosarcoma in cell culture models.     

Protective Effects of Salvianolic Acid B on Schwann Cells Apoptosis Induced by High Glucose

Diabetic peripheral neuropathy (DPN) is one of the most common and debilitating microvascular complications of diabetes, and there is no effective therapy for the prevention or treatment of DPN. Oxidative stress triggers several pathways of injury and may be the unifying factor of hyperglycemia. The aim of this study was to investigate protective effect of Salvianolic acid B (Sal B) on the high glucose (HG)-induced oxidative stress-induced mitochondrial pathway activation and Schwann cells (SCs) apoptosis in vitro. We found that Sal B inhibited the HG-induced oxidative stress by reducing ROS and 8-hydroxy-2-deoxy Guanosine (8-OHdG) production, and mitochondrial depolarization and apoptosis in SCs in a dose-dependent manner. Furthermore, Sal B down-regulated the HG-mediated Bax expression and AIF nuclear translocation and the release of cytochrome c, but up-regulated the HG-induced BcL-2 expression in SCs. In addition, Sal B attenuated the HG-induced activation of caspase 3 and 9 and minimized the cleavage of PARP in SCs. Our results indicated that Sal B antagonized the HG-induced oxidative stress, activation of the mitochondrial pathway and apoptosis in SCs.     

Effect of All-Trans Retinoic Acid on the Differentiation of U87 Glioma Stem/Progenitor Cells

GSPCs (glioma stem/progenitor cells) were isolated from U87 glioma cell lines by serum-free neural stem cell medium. Four concentrations (1, 2, 4, and 8 μmol/L) of ATRA (all-trans retinoic acid) were used to induce the differentiation of GSPCs in the medium with or without growth factors. The effect of ATRA on the differentiation of GSPCs was analyzed by flow cytometry, real-time-PCR, and immunofluorescence. The differentiation of GSPCs could be induced by 1 or 2 μmol/L ATRA when GSPCs were cultured in growth factor-free medium. The detection of real-time-PCR showed that the level of GFAP (glial fibrillary acidic protein) mRNA of differentiated GSPCs in the growth factor-free medium containing 1 μmol/L ATRA group was significantly higher than that in the control group, and there was no significant difference in the level of TUBB-3 mRNA between the two groups. The GSPCs suffered apoptosis in the growth factor-free medium containing 4 or 8 μmol/L ATRA. The differentiation of GSPCs could not be induced by ATRA when GSPCs were cultured in the medium containing growth factors. The percentage of cells in G0/G1 phase was 84.26 ± 2.24 %, and the percentage of apoptosis was 18.95 ± 2.53 % in experimental groups which was similar to those in the control group. In conclusion, ATRA has certain capacity to induce differentiation of GSPCs, while its effective concentration should be controlled strictly. The differentiation of GSPCs induced by ATRA cannot antagonize the formidable differential inhibition of epidermal growth factor and basic fibroblast growth factor.     

Non-Thermal Atmospheric Pressure Plasma Preferentially Induces Apoptosis in p53-Mutated Cancer Cells by Activating ROS Stress-Response Pathways

Non-thermal atmospheric pressure plasma (NTAPP) is an ionized gas at room temperature and has potential as a new apoptosis-promoting cancer therapy that acts by generating reactive oxygen species (ROS). However, it is imperative to determine its selectivity and standardize the components and composition of NTAPP. Here, we designed an NTAPP-generating apparatus combined with a He gas feeding system and demonstrated its high selectivity toward p53-mutated cancer cells. We first determined the proper conditions for NTAPP exposure to selectively induce apoptosis in cancer cells. The apoptotic effect of NTAPP was greater for p53-mutated cancer cells; artificial p53 expression in p53-negative HT29 cells decreased the pro-apoptotic effect of NTAPP. We also examined extra- and intracellular ROS levels in NTAPP-treated cells to deduce the mechanism of NTAPP action. While NTAPP-mediated increases in extracellular nitric oxide (NO) did not affect cell viability, intracellular ROS increased under NTAPP exposure and induced apoptotic cell death. This effect was dose-dependently reduced following treatment with ROS scavengers. NTAPP induced apoptosis even in doxorubicin-resistant cancer cell lines, demonstrating the feasibility of NTAPP as a potent cancer therapy. Collectively, these results strongly support the potential of NTAPP as a selective anticancer treatment, especially for p53-mutated cancer cells.     

Role of Autophagy in Capsaicin-Induced Apoptosis in U251 Glioma Cells

In recent years, the role of capsaicin in cancer prevention and treatment has gained people’s attention. However, the mechanism of anti-glioma cells by capsaicin has not been elucidated. Here, we discuss the mechanism of capsaicin in U251 cells. Cell viability was detected by MTT and extracellular LDH measurements, while immunofluorescence was performed to measure changes of LC3 in U251 cells. The expressions of LC3II, Puma-α, Beclin1, P62, Procaspase-3, and P53 were observed by immunoblotting. The cell viability decreased and the punctate patterns of LC3 in U251 cells were observed after Capsaicin treatment. Meanwhile, the expressions of Beclin1, P62, and Puma-α increased. After using 3-MA, the expressions of Beclin1 and Procaspase-3 were reduced while those of P53 and Puma-α increased. The expression of LC3II was increased after Pifithrin-α treatment. Therefore, we believed that capsaicin could induce apoptosis in U251 cells, and the inhibition of autophagy could contribute to apoptosis.