manumycin诱导舌鳞癌Tca8113细胞凋亡的作用及机制

目的研究manumycin抑制Tca8113细胞的生长和诱导细胞凋亡的作用及机制。方法细胞毒作用以MTT法测定;凋亡细胞形态以Hoechst33258染色后荧光显微镜观察;凋亡率的检测以AnnexinV染色,流式细胞仪检测;细胞内活性氧(ROS)和线粒体跨膜电位(ΔΨm)分别用DCFH-DA和DiOC6荧光探针标记,流式细胞仪检测;蛋白质定量检测以Westernblot法。结果manumycin浓度依赖性抑制Tca8113细胞的生长,IC50为(11.33±0.63)μmol.L-1;manumycin可浓度和时间依赖性诱导Tca8113细胞的凋亡,过氧化物清除剂N-乙酰半胱氨酸能清除manumycin介导的细胞活性氧的增加,抑制线粒体跨膜电位降低及细胞凋亡。结论manumycin体外显著抑制舌鳞癌Tca8113的生长及诱导细胞凋亡,其机制可能通过激活线粒体依赖性凋亡通路有关。     

Salinomycin对乳腺癌阿霉素耐药细胞株MCF-7/DOX的增殖抑制作用及机制

目的本研究旨在探讨Salinomycin对乳腺癌阿霉素耐药细胞株MCF-7/DOX增殖和凋亡的影响及可能作用机制。方法 MTS实验检测Salinomycin对MCF-7/DOX细胞增殖的影响;Annexin V-FITC/PI染色检测Salinomycin对MCF-7/DOX耐药细胞凋亡的影响;DCFH-DA染色检测Salinomycin对MCF-7/DOX耐药细胞活性氧(reactive oxygen species,ROS)产生的影响;JC-1法测定细胞线粒体膜电位;Western blot法检测细胞凋亡相关蛋白BAX、BCL-2、caspase-3和caspase-9的表达变化。结果 Salinomycin能明显抑制MCF-7/DOX耐药细胞增殖,且具有浓度依赖性;流式分析发现Salinomycin能够诱导MCF-7/DOX细胞凋亡,增加细胞内ROS水平,降低细胞线粒体膜电位;与对照组相比较,Salinomycin处理明显抑制BCL-2的表达,上调BAX、cleaved caspase-3和cleaved caspase-9的蛋白表达;抗氧化剂N-acetylcysteine(NAC)则逆转上述作用。结论 Salinomycin能够诱导MCF-7/DOX细胞凋亡,其机制可能与Salinomycin诱导ROS的产生,激活线粒体凋亡途径有关。     

雷公藤红素促进RIP1蛋白的去泛素化增强TNF-α对结肠癌细胞的凋亡诱导活性的研究

目的 探讨中药活性成分雷公藤红素对TNF-α体外抗结肠癌活性的影响并研究其机制。方法 用雷公藤红素联合TNF-α体外治疗结肠癌细胞系SW480,MTT法检测SW480细胞的细胞活力。SW480细胞用雷公藤红素联合TNF-α治疗后,Annexin V/PI染色法检测细胞的凋亡,Western blot法检测细胞caspase-8、caspase-9和caspase-3的活化和对CYLD蛋白表达的影响,并用免疫共沉淀法检测SW480细胞RIP1蛋白的泛素化水平。结果 雷公藤红素联合TNF-α对结肠癌细胞系SW480的细胞活力抑制率和凋亡诱导活性均显著高于雷公藤红素及TNF-α单治疗组。雷公藤红素联合TNF-α对SW480细胞caspase-8、caspase-9和caspase-3的活化显著高于雷公藤红素及TNF-α单治疗组,且两者联合治疗后,caspase-8的活化时间显著早于caspase-9和caspase-3。SW480细胞用雷公藤红素联合TNF-α治疗后,其RIP1蛋白的泛素化水平显著低于雷公藤红素及TNF-α单治疗组。进一步研究发现,雷公藤红素能显著诱导SW480细胞CYLD蛋白的表达,而TNF-α对CYLD的表达水平无影响,当用小干扰RNA沉默CYLD的表达后,雷公藤红素对TNF-α的协同效应丧失。结论 雷公藤红素通过促进RIP1蛋白的去泛素化增强TNF-α对结肠癌细胞的凋亡诱导活性。     

雷酚萜甲醚抑制人胃癌细胞AGS增殖及诱导凋亡作用研究

目的研究雷酚萜甲醚(TME)在体外对人胃癌AGS细胞的增殖抑制和诱导凋亡作用。方法采用MTT法观察TME对人胃癌AGS细胞、正常人胃黏膜上皮细胞GES-1的增殖抑制作用;克隆形成实验观察细胞克隆的形成;光镜下及AO/EB染色观察细胞形态;流式细胞术检测细胞凋亡和细胞周期;JC-1染色和DCFH-DA荧光探针分别检测TME对AGS细胞线粒体膜电位的改变和活性氧产生的影响;Western blot检测凋亡蛋白caspase-3、caspase-8和Bcl-2、Bax表达情况,以及caspase广谱抑制剂z-VAD-fmk对caspase-3、caspase-8蛋白表达的影响。结果 TME可明显抑制人胃癌AGS细胞的增殖,并诱导其凋亡,作用48 h时IC50为23.85μmol·L-1,而对正常人胃黏膜上皮细胞GES-1的抑制作用明显低于AGS。TME能够抑制AGS细胞克隆形成,并使细胞出现明显的凋亡形态改变。Annexin V-FITC/PI双染实验表明,随TME剂量的增加,细胞凋亡百分数也增加。JC-1和DCFH-DA结果显示,TME使细胞内线粒体膜电位降低、细胞内活性氧水平增加。Western blot结果显示,TME增加了Bax/Bcl-2的比例,激活caspase-8和caspase-3,并且加入z-VAD-fmk后,caspase-3、caspase-8蛋白的表达降低。TME可使AGS细胞周期阻滞于G0/G1期。结论 TME能抑制人胃癌AGS细胞增殖和诱导凋亡,抗肿瘤作用机制与激活凋亡通路、影响细胞周期及Bcl-2蛋白家族相关。     

雷公藤红素对体外人肝癌HepG2细胞增殖、凋亡的影响及机制研究

目的:研究雷公藤红素对体外人肝癌HepG2细胞增殖、凋亡的影响,并探讨其作用机制。方法:采用CCK-8法测定2、5、10μmol/L雷公藤红素分别作用24、48、72 h后的细胞活性,并计算增殖抑制率和半数抑制浓度(IC_(50));采用流式细胞术检测2、5、10μmol/L雷公藤红素分别作用24 h后细胞的凋亡率及周期变化,并以二甲基亚砜(DMSO)为阴性对照;采用罗丹明123染色法测定2、5、10μmol/L雷公藤红素分别作用48 h后的细胞线粒体膜电位,并以DMSO为阴性对照;采用Western blot法检测5μmol/L雷公藤红素作用0、12、24、36 h后细胞中促凋亡相关基因Bax和B淋巴细胞瘤2(Bcl-2)的蛋白表达。结果:2、5、10μmol/L雷公藤红素均可抑制细胞的增殖,IC_(50)为5.834μmol/L。2、5、10μmol/L雷公藤红素均可诱导细胞凋亡。5、10μmol/L雷公藤红素可阻滞细胞于G_0/G_1、S期,并可降低线粒体膜电位,较阴性对照差异均有统计学意义(P<0.05或P<0.01),且以上作用均具有浓度依赖性。5μmol/L雷公藤红素作用12、24、36 h后可上调细胞中Bax蛋白表达、下调Bcl-2蛋白表达,并呈现一定的时间依赖性,较0 h时差异有统计学意义(P<0.05或P<0.01)。结论:雷公藤红素可明显抑制体外人肝癌HepG2细胞的增殖并诱导其凋亡,其机制可能与增强线粒体通透性、促使凋亡诱导因子释放有关。     

三萜皂苷Saxifragifolin D抑制人肝癌耐药细胞HepG2/ADM生长并诱导细胞凋亡作用研究

目的研究Saxifragifolin D(SD)对人肝癌耐药细胞HepG2/ADM的生长抑制及诱导凋亡作用。方法采用MTT法观察SD对HepG2/ADM细胞的增殖抑制作用,应用流式细胞仪分析SD对细胞周期的影响,AnnexinⅤ-FITC/PI双染检测凋亡细胞比率,JC-1染色观察SD对细胞内线粒体膜电位的影响,Western blot检测凋亡相关蛋白caspase-9,caspase-3和PARP的激活及c-Raf,MEK和ERK蛋白的表达和磷酸化水平。结果 SD可以明显抑制人肝癌耐药细胞HepG2/ADM的增殖。细胞周期检测发现SD诱导细胞产生亚二倍体凋亡峰,同时细胞凋亡率也由对照组的5.3%增加到34.8%和47.8%。线粒体膜电位检测结果显示SD导致细胞内线粒体膜电位的明显降低。Western blot检测结果表明caspase-9,caspase-3被激活,PARP被剪切活化,cytochrome C由线粒体释放至胞质,c-Raf、MEK和ERK蛋白的磷酸化水平降低。结论 SD可以抑制人肝癌耐药细胞HepG2/ADM增殖并诱导其凋亡,作用机制可能与线粒体功能障碍及抑制c-Raf/MEK/ERK通路的活化有关。     

新型多胺缀合物NNAMB诱导B16细胞凋亡及分化作用

目的评价新型多胺缀合物NNAMB对B16黑色素瘤细胞诱导凋亡及分化作用。方法以MTT法、台盼蓝拒染法检测细胞活力;Hoechst33258染色观察细胞形态变化;流式细胞仪检测细胞周期变化、凋亡率及线粒体膜电位的变化;酶标仪检测caspase-3、-8、-9的活性及B16细胞内黑色素含量、酪氨酸酶活性等的变化。结果NNAMB在高剂量(>0.1μmol·L-1)下呈现剂量及时间依赖性的抑制B16黑色素瘤细胞的生长、诱导凋亡、降低线粒体膜电位、促进Caspase-3及-9的活化,但caspase-8活性与对照组细胞相比变化差异无显著性;NNAMB在低剂量(<0.1μmol·L-1)下通过增强酪氨酸酶活性,增加黑色素生成等诱导B16细胞分化。结论NNAMB在高剂量下通过线粒体/caspase-9/caspase-3途径诱导B16细胞凋亡;低剂量诱导细胞分化。     

黄芪甲苷对甲基乙二醛诱导的人视网膜色素上皮细胞损伤的保护作用研究

目的研究黄芪甲苷(AS-Ⅳ)对甲基乙二醛(MGO)诱导的人视网膜色素上皮细胞损伤的保护作用及分子机制。方法利用MGO诱导ARPE-19细胞损伤,CCK-8法检测细胞活力,Hoechst 33342染色法观察细胞核形态,流式细胞仪检测细胞凋亡,试剂盒测定细胞内活性氧(ROS)水平、超氧化物歧化酶(SOD)水平和脂质过氧化物丙二醛(MDA)含量,JC-1染色法观察线粒体膜电位的变化,Western blot法检测Bcl-2、Bax和PARP蛋白的表达量,荧光酶标法检测caspase家族蛋白caspase-9和caspase-3的活化水平。结果MGO能剂量依赖性地降低ARPE-19的细胞活力,AS-Ⅳ预处理能够明显逆转MGO引起的细胞活力下降(P<0.05),改善细胞核形态,减少细胞凋亡,减少ROS和MDA的产生(P<0.05),增加SOD活力(P<0.05),抑制线粒体膜电位的下降,提高Bcl-2/Bax蛋白表达率(P<0.05)和PARP的表达水平,降低caspase-9和caspase-3的活化水平(P<0.05)。结论 AS-Ⅳ对MGO损伤的ARPE-19细胞有明显的保护作用,其作用机制是提高细胞抗氧化能力,调节线粒体通路蛋白的表达,从而抑制细胞凋亡。     

血根碱抑制人乳腺癌细胞MCF-7增殖的机制研究

目的研究血根碱(Sanguinaria canadensis,SAN)诱导人乳腺癌细胞MCF-7凋亡可能的作用机制。方法 MTT法检测SAN对MCF-7细胞存活率的影响;激光扫描共聚焦显微镜观察SAN对MCF-7细胞内活性氧(reactive oxygen species,ROS)含量的影响;化学发光法检测SAN对MCF-7细胞内caspase-3、caspase-8、caspase-9活性的影响。结果 SAN能降低MCF-7细胞存活率;SAN可明显升高MCF-7细胞内ROS含量,升高细胞内caspase-3、caspase-8、caspase-9的活性,而这种作用能被抗氧化剂NAC抑制。结论以上结果证明SAN能够抑制人乳腺癌细胞MCF-7增殖,其机制可能是通过升高细胞内ROS水平,激活caspase级联反应,进而诱导细胞凋亡发挥作用。     

雷公藤红素升高ROS和抑制NF-κB通路抑制肺癌H460细胞生长

摘要：目的:探究雷公藤红素对人肺癌H460细胞的体外抑制作用。方法:使用MTT法检测雷公藤红素对H460细胞生长的影响;使用细胞集落实验检测雷公藤红素对H460细胞集落形成的影响;采用细胞流式仪检测雷公藤红素及雷公藤红素联用N-乙酰半胱氨酸（NAC）对活性氧（ROS）水平的影响;采用MTT法检测雷公藤红素联用NAC对H460细胞生长的影响;蛋白质印迹法检测雷公藤红素及联用NAC后对凋亡相关蛋白Bcl-2和Bax的表达水平影响。同时,进一步使用蛋白质印迹法检测雷公藤红素对核因子κB（NF-κB）通路中IκBα表达水平的影响。结果:雷公藤红素浓度依赖性的抑制H460细胞的生长和集落形成（P<0.05或P<0.01）,浓度依赖性的促进细胞内ROS水平（P<0.01）,同时能够通过升高ROS水平诱导H460细胞死亡（P<0.01）,升高Bax蛋白及抑制Bcl-2蛋白的表达（P<0.05或P<0.01或P<0.001）,促进IκBα的表达（P<0.05或P<0.01）。结论:雷公藤红素表现出高效抗肺癌作用,能升高ROS水平介导凋亡相关蛋白的表达以及抑制NF-κB通路来抑制人肺癌H460细胞的生长。     

Three components of cigarette smoke altered the growth and apoptosis of metastatic colon cancer cells via inducing the synthesis of reactive oxygen species and endoplasmic reticulum stress

Cigarette smoke (CS) is a well-known risk factor for carcinogenesis and has been found to be related to the occurrence and development of colon cancer. In this study, the effect of formaldehyde (FA), benzene (Bz), and isoprene (IP), which are included in main components of CS, on cell viability and apoptosis of SW620 colorectal cancer cells was examined to identify the connection between CS components and colon cancer. In cell viability assay, FA, Bz, and IP decreased cell viability of SW620 cells in a dose dependent manner. In Western blot assay, the protein expression of cell cycle related genes, cyclin D1 & E1, was decreased by FA, Bz, and IP, which corresponded to their inhibitory effect on cell viability. In addition, FA, Bz, and IP increased the protein expression of pro-apoptotic genes, C/EBP homologous protein (CHOP) and Bax, and reduced the protein expression of anti-apoptotic gene, Bcl-2. In reactive oxygen species (ROS) assay using dichlorofluorescin diacetate (DCFH-DA), FA, Bz, and IP increased the ROS production in SW620 cells. In the measurement of apoptotic cells, the numbers of apoptotic cells were increased by the treatment of FA, Bz, and IP. As CHOP is an endoplasmic reticulum (ER)-stress related apoptosis marker of which production is induced by ROS, it was considered that these CS components induce apoptosis of SW620 cells by increasing ROS synthesis and ER-stress. Taken together, these results showed that CS components, i.e., FA, Bz, and IP, inhibited the cell viability of SW620 cells by down-regulating the protein expression of cyclin D1 & E1 and induced apoptosis of SW620 cells by increasing ROS production and simultaneously activating ER-stress.     

Reactive oxygen species-independent rapid initiation of mitochondrial apoptotic pathway by chelerythrine

Chelerythrine, formerly identified as a protein kinase C inhibitor, has also been shown to inhibit the anti-apoptotic Bcl-2 family proteins. However, recent studies have now demonstrated that chelerythrine can induce the loss of mitochondrial membrane potential (ΔΨ_m), a membrane permeability transition (MPT), and the subsequent activation of the mitochondrial apoptotic pathway, even in the cells deficient in Bax and Bak. This suggests the existence of an alternative Bax/Bak-independent pathway for apoptosis. The generation of reactive oxygen species (ROS) from the mitochondrial electron transport chain (ETC) is also implicated in the cytotoxity elicited by chelerythrine. In our current study, we show that chelerythrine induces the rapid apoptotic death of H9c2 cardiomyocyte-derived cells within 8 min of treatment. The proteolytic activation of caspase9 and caspase3, crucial mediators of the mitochondrial apoptotic pathway, are also observed within 6 min of exposure to this drug. The generation of ROS is detected but at only marginal levels in the treated cells. The inhibition of the mitochondrial ETC by rotenone and malonate had almost no effects on ROS generation but in both cases effectively inhibited both cell death and the caspase activation induced by chelerythrine. Hence, chelerythrine initiates the rapid mitochondrial apoptotic death of H9c2 cardiomyoblastoma cells in a manner that is likely independent of the generation of ROS from mitochondria.     

二萜类化合物excisanin A诱导人结肠癌SW620细胞凋亡及机制研究

目的本文研究大萼香茶菜有效单体exc isan in A诱导人结肠癌SW 620细胞株凋亡及其分子机制。方法MTT法检测细胞增殖抑制作用,AnnexinV/PI双染法检测细胞早期凋亡率,W estern b lot法检测exc isan in A对PARP、caspase-3、caspase-9剪切片断的影响,及对MAPKs通路相关蛋白,包括p-ERK、ERK、p-JNK、JNK、p-p38、p38、c-Jun表达的影响。结果Excisanin A对结肠癌SW620细胞株生长具有明显的抑制作用,并呈浓度依赖性,其IC50值为8.22μmol.L-1。用8.71μmol.L-1excisanin A处理SW620细胞12、24、36 h,AnnexinV/PI双染检测细胞的早期凋亡,其凋亡率分别为17.2%、20.5%、13.8%,而对照组细胞的凋亡率仅为1.9%(P<0.05)。不同浓度的excisanin A作用于SW620细胞48h后,Western blot法检测发现PARP、caspase-3,caspase-9 3种蛋白均出现断裂片断,并随着浓度的增加断裂更明显。进一步研究发现,excisanin A处理SW620细胞后,JNK、p38的磷酸化水平明显升高,c-Jun的表达亦增高。结论Excisa-nin A具有明显的细胞毒作用,能诱导SW620细胞凋亡,JNK和p38途径的激活可能是其诱导凋亡的分子机制之一。     

吡唑啉酮铜配合物通过内外信号途径诱导人肝癌细胞BEL-7404凋亡

目的探讨新型吡唑啉酮铜配合物(P-FAH-Cu-bpy)对人肝癌细胞BEL-7404的诱导凋亡机制。方法通过溶液法制备得到吡唑啉酮铜配合物P-FAH-Cu-bpy。X-射线单晶衍射实验测定晶体结构。MTT法检测P-FAH-Cu-bpy体外对BEL-7404细胞活性的影响。倒置显微镜和Hoechst 33258染色法观察细胞及核形态变化。流式细胞术检测P-FAHCu-bpy对BEL-7404细胞凋亡、周期、ROS、线粒体膜电位的影响。划痕实验检测细胞迁移。Western blot检测P-FAHCu-bpy对BEL-7404细胞凋亡、迁移及侵袭相关蛋白表达的影响。结果 P-FAH-Cu-bpy是一个具有扭曲的四方锥构型的五配位铜(Ⅱ)配合物;呈浓度和时间依赖性地抑制了BEL-7404细胞增殖,诱导了细胞凋亡,将细胞周期阻滞在G2/M期,降低了细胞线粒体膜电位,增加了胞内ROS水平;上调了细胞Bax、细胞色素C、Cleaved-caspase-3/9/8和Cleaved-PARP表达量,而下调了caspase-7、Bcl-2表达水平;抑制了细胞的迁移和侵袭。结论 P-FAH-Cu-bpy通过内外凋亡信号途径抑制了人肝癌细胞BEL-7404生长。     

Oxidative stress-mediated mitochondrial apoptosis induced by the acaricide,fenpyroximate, on cultured human colon cancer HCT 116 cells

Fenpyroximate (FEN) is an acaricide that inhibits mitochondrial electron transport at the NADH-coenzyme Q oxidoreductase (complex I). The present study was designed to investigate the molecular mechanisms underling FEN toxicity on cultured human colon carcinoma cells (HCT116). Our data showed that FEN induced HCT116 cell mortality in a concentration dependent manner. FEN arrested cell cycle in G0/G1 phase and increased DNA damage as assessed by comet assay. Induction of apoptosis was confirmed in HCT116 cells exposed to FEN by AO-EB staining and Annexin V-FITC/PI double staining assay. Moreover, FEN induced a loss in mitochondrial membrane potential (MMP), increased p53 and Bax mRNA expression and decreased bcl2 mRNA level. An increase in caspase 9 and caspase 3 activities was also detected. All toghether, these data suggest that FEN induce apoptosis in HCT116 cells via mitochondrial pathway. To check the implication of oxidative stress in FEN-induced cell toxicity, we examined the oxidative stress statue in HCT116 cells exposed to FEN and we tested the effect of a powerful antioxidant, N-acetylcystein (NAC), on FEN-caused toxicity. It was observed that FEN enhanced ROS generation and MDA levels and disturbed SOD and CAT activities. Besides, cell treatment with NAC significantly protected cells from mortality, DNA damage, loss of MMP, and caspase 3 activity induced by FEN. To the best of our knowledge, this is the first study showing that FEN induced mitochondrial apoptosis via ROS generation and oxidative stress.     

2,4-dinitrophenol induces G1 phase arrest and apoptosis in human pulmonary adenocarcinoma Calu-6 cells.

2,4-dinitrophenol (DNP) is an uncoupler of oxidative phosphorylation in the mitochondria. Here, we investigated the effect of DNP on the growth of Calu-6 lung cancer cells in view of cell cycle, apoptosis, ROS production and GSH content. DNP dose-dependently decreased cell viability at 72 h (EC50 of about 200 microM) as measured by a MTT assay. The lower doses of DNP induced a G1 arrest of the cell cycle in Calu-6 cells. Analysis of the cell cycle regulatory proteins demonstrated that DNP decreased the steady-state levels of cyclin proteins and cyclin dependent kinase (CDK), but increased the protein levels of cyclin dependent kinase inhibitor (CDKI) p27. DNP also caused a marked increase in apoptosis, as evidenced by DNA fragmentation (sub-G1 DNA content), DAPI staining, the loss of mitochondrial membrane potential (DeltaPsim), externalization of phosphatidylserine (PS). In addition, DNP-treated cells significantly increased the intracellular H2O2 and O2.- levels. All of caspase inhibitors could markedly rescue Calu-6 cells from DNP-induced cell death and only pan-caspase inhibitor, Z-VAD-FMK, could slightly prevent the loss of mitochondrial membrane potential (DeltaPsim). However, none of the caspase inhibitors reduced the increased H2O2 levels, but the increased O2.- levels was slightly attenuated by pan-caspase inhibitor. In addition, the depletion of GSH content in DNP-treated cells was prevented by all of caspase inhibitors. In conclusion, DNP, which induced ROS and reduced GSH content, inhibited the growth of Calu-6 cells via cell cycle arrest at G1 phase and apoptosis.     

百里醌对人胶质瘤细胞凋亡的作用及其机制研究

目的 分析百里醌对胶质瘤U87细胞生长抑制和凋亡诱导的功能.方法 体外胶质瘤细胞株U87以及人星形胶质细胞株NHA中添加不同浓度百里醌后,CCK-8法检测细胞活力;克隆形成实验观察U87细胞形成细胞克隆的能力;流式细胞术检测细胞周期和ROS含量;Hoechst染色法和流式细胞术测定细胞凋亡;流式细胞术(JC-1荧光染色...     

Betulin induces reactive oxygen species-dependent apoptosis in human gastric cancer SGC7901 cells

Betulin, an abundant natural compound, significantly inhibited the cell viability of advanced human gastric cancer SGC7901 cells. Mechanism study demonstrated that betulin induced apoptosis through mitochondrial Bax and Bak accumulation-mediated intrinsic apoptosis pathway. Downregulation of the anti-apoptosis proteins Bcl-2 and XIAP was involved during betulin-induced cell apoptosis. Reactive oxygen species (ROS) was generated in cells after betulin treatment in a time- and dose-dependent manner. Addition of antioxidant N-acetyl-l-cysteine (NAC) significantly attenuated betulin-induced ROS generation as well as Bcl-2 and XIAP downregulation. The mitochondrial accumulation of Bax and Bak, as well as caspase activity, was also remarkably inhibited by NAC treatment, indicating that ROS are important signaling intermediates that lead to betulin-induced apoptosis by modulating multiple apoptosis-regulating proteins in SGC7901 cells.     

γ-Tocotrienol induces apoptosis in human T cell lymphoma through activation of both intrinsic and extrinsic pathways

Tocotrienols are members of vitamin E family and possess broad biological activities including antioxidant, anti-inflammatory and antitumor effects. In the present study, we examine the potential of α-tocotrienol (AT) and γ-tocotrienol (GT) in inhibiting the proliferation of human T cell lymphoma Jurkat cells and elucidate the pathways involved in anti tumor effects of GT. GT but not AT inhibited proliferation and induced apoptosis in Jurkat cells in a dose dependent manner. GT treatment resulted in elevated mitochondrial ROS production, activation of JNK and suppression of ERK and p38 MAPK. GT also induced calcium release, loss of mitochondrial membrane potential and cytochrome c release from the mitochondria. These changes were accompanied by increase in Bax expression with a concomitant decrease in Bcl-xl expression suggesting activation of mitochondrial apoptotic pathway. GT induced increase in mitochondrial ROS was abrogated by catalase. Besides, GT also up-regulated surface expression of Fas and FasL on Jurkat cells. Further, caspase activation and PARP degradation were also seen in cells treated with GT. Inhibitors of caspase-8 and caspase-9 significantly abrogated GT mediated apoptosis. In contrast GT was not toxic to normal human peripheral blood mononuclear cells suggesting differential cytotoxicity towards normal lymphocytes and transformed lymphoma cells. Cellular uptake studies with tocotrienols showed higher intracellular accumulation of GT as compared to AT which may be responsible for its better antitumor activity. Our results show antitumor effects of GT in human lymphoma cells via increased mitochondrial ROS generation and activation of both intrinsic and extrinsic apoptotic pathways.     

The Strong Anti-Tumor Effect of Smp24 in Lung Adenocarcinoma A549 Cells Depends on Its Induction of Mitochondrial Dysfunctions and ROS Accumulation

Non-small cell lung cancer (NSCLC) is the leading cause of death in lung cancer due to its aggressiveness and rapid migration. The potent antitumor effect of Smp24, an antimicrobial peptide derived from Egyptian scorpion Scorpio maurus palmatus via damaging the membrane and cytoskeleton have been reported earlier. However, its effects on mitochondrial functions and ROS accumulation in human lung cancer cells remain unknown. In the current study, we discovered that Smp24 can interact with the cell membrane and be internalized into A549 cells via endocytosis, followed by targeting mitochondria and affect mitochondrial function, which significantly causes ROS overproduction, altering mitochondrial membrane potential and the expression of cell cycle distribution-related proteins, mitochondrial apoptotic pathway, MAPK, as well as PI3K/Akt/mTOR/FAK signaling pathways. In summary, the antitumor effect of Smp24 against A549 cells is related to the induction of apoptosis, autophagy plus cell cycle arrest via mitochondrial dysfunction, and ROS accumulation. Accordingly, our findings shed light on the anticancer mechanism of Smp24, which may contribute to its further development as a potential agent in the treatment of lung cancer cells.