环氧化酶-2抑制药对肺癌细胞和骨肉瘤细胞生长的抑制作用

目的观察选择性环氧化酶-2（COX-2）抑制药塞来昔布、罗非昔布对人骨肉瘤细胞株（HOS-8603）、肺癌细胞株（A-549）的作用以及罗非昔布、塞来昔布对两种细胞抑制效应的比较。方法MTT法测定体外培养的细胞株HOS-8603、A-549对不同浓度的罗非昔布和塞来昔布的敏感性，流式细胞仪分析细胞增殖周期的影响及凋亡。结果塞来昔布、罗非昔布均可明显抑制HOS 8603、A-549细胞的生长（P＜0.05），抑制效应呈现浓度依赖型和时间依赖型。HOS-8603和A-549细胞分裂阻滞在G2/M期，出现凋亡峰，塞来昔布对HOS 8603的作用强于罗非昔布。结论COX-2抑制药塞来昔布尼罗非昔布对骨肉瘤细胞、肺癌细胞的生长有抑制作用，有望成为抗肿瘤新药。     

姜黄素增加 U937细胞对 TRAIL 的敏感性的凋亡机制研究

目的：观察姜黄素增敏肿瘤坏死因子相关凋亡诱导配体（TNF-related apoptosis-inducing ligand,TRAIL）对人白血病 U937细胞株的细胞毒作用,探讨其凋亡机制。方法取对数生长期的白血病 U937细胞,MTT 法检测不同浓度的姜黄素和 TRAIL对 U937细胞的增殖抑制率及杀伤率,流式细胞术检测凋亡。结果姜黄素对白血病细胞 U937有明显抑制作用,且呈剂量依耐性,与 TRAIL 联用后可显著促进 U937的凋亡率。不同浓度的姜黄素作用24 h 后,可显著上调死亡受体5（Death receptor 5, DR5）的表达。结论姜黄素增敏 TRAIL 对白血病 U937的抑制作用明显,其凋亡机制可能是与上调 DR5有关。     

塞来昔布对非小细胞肺癌化疗的增敏作用及机制

目的 探讨塞来昔布对非小细胞肺癌(NSCLC)的化疗增敏作用及其机制.方法 应用噻唑蓝比色法(MTT)检测顺铂(DDP)、足叶乙甙(VP16)单独应用及与塞来昔布联合应用的增殖抑制率,并根据金氏公式计算Q值,评价两药的合用效应.应用流式细胞术检测各处理组的凋亡率.结果 DDP联合塞来昔布后对NSCLC抑制作用明显增强,二者合用有协同作用.VP16联合塞来昔布后对NSCLC抑制作用明显增强,二者合用有协同作用.塞来昔布与顺铂联合用药的凋亡率明显高于单用药组(P＜0.01).结论 塞来昔布可增强DDP、VP16对NSCLC的增殖抑制作用,具有化疗增敏作用,其机制可能与塞来昔布促进凋亡有关.     

贝伐单抗对肝癌细胞株HepG2增殖的抑制作用

目的通过体外实验探讨贝伐单抗(bevacizumab)对人肝癌细胞HepG2增殖的抑制作用及可能的分子机制。方法MTT法检测贝伐单抗对肝癌细胞增殖的抑制作用;流式细胞仪检测细胞凋亡;RT-PCR分析肝癌细胞株VEGF、Flt-1、KDR mRNA表达量的变化。结果不同质量浓度的贝伐单抗对肝癌细胞株HepG2的增殖有抑制作用;贝伐单抗可诱导肝癌细胞株HepG2的凋亡;贝伐单抗作用于肝癌细胞株HepG2后,其VEGF、KDR mRNA表达量均减少。结论贝伐单抗可能通过阻断VEGF的促增殖作用而抑制HepG2细胞增殖。     

洛铂对肝癌细胞HepG2的放疗增敏效应

目的 探讨洛铂对肝癌细胞的放疗增敏效应.方法 用MTT法确定洛铂对肝癌细胞株HepG2半数抑制浓度(IC50),流式细胞仪检测1/4 IC50、1/8 IC50洛铂对HepG2细胞周期、凋亡的影响,蛋白免疫印迹检测凋亡相关蛋白Bcl-2、Bax、Caspase-3的表达,细胞克隆形成实验研究洛铂对HepG2的放射增敏比.结果 洛铂对肝癌细胞株HepG2细胞毒作用呈剂量依赖性,半数抑制浓度为1.85μg/ml,不同浓度洛铂组(1/4 IC50组、1/8 IC50组)均观察到HepG2细胞凋亡和G2/M期阻滞明显增加(P＜0.05);两组洛铂干预组肝癌细胞Bcl-2表达下降,Bax、Caspase-3表达水平升高;洛铂对肝癌细胞HepG2的放疗增敏比分别是1.12、1.28.结论 洛铂具有放射增敏作用;其机制可能与促进肝癌细胞凋亡以及细胞G2/M期阻滞相关.     

TRAIL及其受体在咖啡因抑制肝癌细胞系HepG2增殖中的作用

目的探讨TRAIL及其受体在咖啡因(caffeine)抑制肝癌细胞系HepG2增殖中的作用。方法HepG2细胞分别经caffeine、TRAIL及caffeine+TRAIL作用24h,采用MTT法检测HepG2细胞增殖抑制情况,根据中效原理进行联合用药效应评价;流式细胞仪检测细胞凋亡和细胞周期分布;Westernblot法检测caffeine作用不同时间HepG2细胞中TRAIL受体相关蛋白的表达。结果在1.25～20mmol.L-1浓度范围内,caffeine明显抑制HepG2细胞增殖;在0.01275～0.2040μmol.L-1浓度范围内,TRAIL可明显抑制HepG2细胞增殖。Caffeine联合TRAIL在多数效应范围内的合用指数小于1,具有协同作用。Caffeine5mmol.L-1和TRAIL0.0510μmol.L-1联合用药组HepG2细胞凋亡率明显高于各单独用药组,且两者联合用药对HepG2细胞周期具有明显的影响,使G0/G1期细胞比例明显增加,S期及G2/M期细胞比例明显减少;caffeine5mmol.L-1作用HepG2细胞24h时,其DR4及DR5的表达量明显增加,而DcR1和DcR2的表达无改变。结论TRAIL在caffeine抑制HepG2细胞增殖过程中具有一定的协同作用,其机制可能与caffeine上调HepG2细胞表面DR4、DR5的表达,联合TRAIL后能够进一步诱导凋亡及调节细胞周期有关。     

塞来昔布对人肺癌A549细胞株增殖抑制和凋亡诱导作用观察

目的 体外研究选择性环氧化酶2 (COX-2)抑制剂塞来昔布对人肺癌细胞株A549增殖和凋亡的影响,并探讨其可能的作用机制.方法 采用噻唑蓝(MTT比色法)观察不同浓度的塞来昔布对人肺癌细胞株A549的增殖抑制作用,TUNEL染色检测细胞凋亡,并用含半胱氨酸的门冬氨酸蛋白水解酶-3(caspase-3)活性检测试剂盒检测其活性变化.结果 塞来昔布能够以浓度依赖性方式有效地抑制K562细胞增殖,药物的Ic50为33.98 μmol·L-1;TUNEL染色分析显示给予不同浓度塞来昔布的细胞与未给予塞来昔布的细胞相比凋亡率有差异(P＜0.05),经塞来昔布处理的A549细胞内caspase-3的A405较正常对照组有显著增加(P＜0.05).结论 塞来昔布能够抑制A549细胞增殖,并呈药物浓度依赖性;塞来昔布能以浓度依赖性方式诱导K562细胞凋亡,其机制涉及caspase-3活化的信号转导途径.     

不同浓度依托咪酯诱导人肝癌HepG2细胞体外凋亡的研究

目的探讨不同浓度的依托咪酯是否具有直接诱导人肝癌HepG2细胞凋亡的作用,寻找依托咪酯临床治疗的新途径。方法人肝癌细胞株HepG2体外扩增培养备用,选取不同浓度的依托咪酯E1、E2、E3和对照组（空白）,分别培养12h、24h、48h后观察。结果与空白对照组相比,培养12h、24h、48h后E1组、E2组人肝癌细胞株HepG2细胞凋亡率无明显差异（P〉0．05）,E3组凋亡率不断增加,具有显著性差异（P〈0．05）;随着培养时间的延长及浓度的不断增加,E1与E2组对比人肝癌细胞株HepG2细胞凋亡率无明显差异（t=1．732,P〉0．05）,E1与E3组对比人肝癌细胞株HepG2细胞凋亡率具有显著性差异（t=1．864,P〈0．05）,E2与E3组对比人肝癌细胞株HepG2细胞凋亡率具有明显差异（f=1．691,P〈0．05）。结论依托咪酯在临床安全有效的浓度下不直接诱导人肝癌HepG2细胞的体外凋亡,浓度及时间达到一定峰值时可具有直接诱导人肝癌HepG2细胞体外凋亡的作用。     

三-(2,3-二溴丙基)异氰脲酸酯通过死亡受体信号通路诱导HepG2细胞凋亡

目的探讨环境外源性污染物三-(2,3-二溴丙基)异氰脲酸酯(TBC)诱导人肝癌细胞株HepG2凋亡的死亡受体途径。方法采用MTT法、流式细胞术确定TBC对HepG2细胞的毒性作用、细胞凋亡率,Western blot法对死亡受体信号通路关键蛋白Caspase-8、FADD、CD95/FAS、DR4、DR5、PARP和TRAIL的蛋白水平表达进行检测。结果 TBC处理浓度增加(0、12.5、25和50)μg/ml对HepG2细胞的增殖抑制作用增强,凋亡峰越明显,表明DNA合成受到抑制。且细胞内PARP蛋白表达量逐渐降低,细胞内的Caspase-8、FADD、CD95/FAS、DR4、DR5和TRAIL蛋白表达量逐渐升高,呈现剂量-效应关系。结论环境外源性污染物TBC具有细胞毒性,且可以通过死亡受体途径进行诱导细胞凋亡,为其他外源性化合物的毒理学研究和早期干预提供了理论基础。     

塞来昔布对肺癌的抑制作用机制研究

目的探讨环氧化酶抑制剂（COX-2）抑制剂塞来昔布对于A549肺癌细胞增殖及其小鼠移植瘤生长的抑制作用及可能机制。方法加不同浓度塞来昔布与A549肺癌细胞共培养,MTT法检测细胞增殖。流式细胞仪法检测细胞凋亡情况。A549细胞移植入BALB／c裸小鼠皮下后,随机分为实验组和对照组,实验组隔日腹腔注射塞来昔布30mg．kg^-1,对照组隔日腹腔注射等体积生理盐水,24d后处死移植瘤小鼠,计算抑瘤率,RT-PCR检测移植瘤组织中COX一2和VEGFmRNA表达水平,同时酶联免疫检测小鼠血清中MMP-9浓度,免疫组化检测瘤组织中微血管密度（MVD）。结果塞来昔布在体外对细胞株A549的生长抑制作用呈剂量、时间依赖性,且经塞来昔布作用后,A549细胞G0／G1期比例增加,S、G2／M期比例下降。在体实验显示,塞来昔布具有明显的抑制A549肺癌移植瘤增殖的作用,同时能抑制移植瘤组织中COX-2、VEGF表达,降低血清MMP-9浓度,减少移植瘤中微血管密度（P〈0．05）。结论塞来昔布在体内外均可显著抑制A549肺癌细胞的增殖,而诱导肿瘤细胞凋亡,抑制肿瘤血管生成和降低癌细胞侵袭能力是其可能的作用机制。     

塞来西布对食管癌ECA-109细胞系放射增敏效应的研究

目的：了解环氧化物酶-2（COX-2）选择性抑制剂——塞来西布对食管癌ECA-109细胞系的放射增敏作用。方法：选择ECA-109细胞系作为试验对象,检测ECA-109细胞系的COX-2表达水平,设塞来西布0.25、50、100μmol/L4个实验组,分别予6MV-X线照射0、2、4、6Gy后,再分别行MTT比色试验、克隆形成实验、流式细胞仪计数,检测细胞的增殖能力、克隆形成能力及凋亡3项指标。结果：不同辐射剂量与不同浓度的塞来西布对ECA-109细胞的增殖、凋亡率作用有统计学差异（P〈0.05）,塞来西布与放射对ECA-109细胞的增殖抑制和诱导凋亡作用随塞来西布的浓度和照射剂量的增加而增强;塞来西布联合放射对ECA-109细胞的存活率、D0值和Dq值作用均小于单纯放射组,Dq变小;塞来西布和4Gy（6MV-X）联合用于ECA-109细胞其凋亡率有统计学差异（P〈0.05）。结论：塞来西布能抑制ECA-109细胞增殖,诱导其凋亡。塞来西布与放射联合应用对ECA-109细胞的增殖抑制、诱导凋亡有协同增强的作用。     

索拉菲尼增强TRAIL 诱导人肝癌细胞凋亡的作用及机制探讨

目的观察索拉菲尼(Sorafenib)是否能增强肿瘤坏死因子相关凋亡诱导配体(TRAIL)诱导人肝癌细胞凋亡并探讨其作用机制。方法体外培养人肝癌HepG2细胞,MTT法测定细胞增殖活性,碘化丙啶(PI)染色流式细胞术(FCM)和细胞凋亡ELISA检测试剂盒检测细胞凋亡,Western blotting分析Mcl-1的表达。结果索拉菲尼具有增强TRAIL诱导人肝癌HepG2细胞凋亡的作用,并呈剂量和时间依赖的方式抑制Mcl-1的表达。Mcl-1过表达能抑制索拉菲尼增强TRAIL诱导HepG2细胞凋亡的作用。结论索拉菲尼通过抑制Mcl-1的蛋白表达增强TRAIL诱导人肝癌细胞凋亡的作用。     

Verrucarin A enhances TRAIL-induced apoptosis via NF-κB-mediated Fas overexpression

We investigated whether verrucarin A (VA) sensitizes HepG2 hepatoma cells to tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-mediated apoptosis. We found that VA alone induces little apoptosis, but when combined with TRAIL (VA/TRAIL), it triggered significant apoptosis, causing little or no toxicity in normal mouse splenocytes. VA/TRAIL-induced cell death is involved in the loss of mitochondrial transmembrane potential and the consequent activation of caspases. Because nuclear factor (NF)-κB inhibition has been known as a critical target in TRAIL-mediated apoptosis, we also investigated the role of NF-κB in VA/TRAIL treatment. We found that VA upregulated the DNA binding activity of NF-κB, but that the antioxidants glutathione and N-acetyl-l-cysteine, as well as NF-κB inhibitor MG132, and mutant-IκB (m-IκB) transfection, significantly downregulated VA/TRAIL-induced cell death by inhibiting caspase-3 and NF-κB activities. Transfection of mutant-eIF2α also resulted in a decrease in VA/TRAIL-induced cell death by inhibiting of caspase-3, but not NF-κB activity. Although VA/TRAIL treatment led to an increase of DR5 expression, transfection of m-IκB had no influence on the DR5 expressional level. Finally, we showed that NF-κB-mediated Fas expression is critical to VA/TRAIL-induced apoptosis. Taken together, these results indicate that VA/TRAIL sensitizes HepG2 cells to apoptosis via NF-κB-mediated overexpression of Fas.     

PI3K/mTOR抑制剂BEZ235抑制HepG2细胞增殖及与阿霉素的协同效应

目的探讨PI3K/Akt和mTOR双重抑制剂BEZ235对HepG2肝癌细胞增殖和凋亡的影响,并观察BEZ235与阿霉素合用的联合作用。方法采用MTT法检测HepG2细胞增殖;流式细胞术分析细胞周期变化;AnnexinⅤ-FITC试剂盒检测细胞凋亡;免疫印迹法检测蛋白表达水平。结果BEZ235 2.5μmol.L-1～7.5μmol.L-1能够抑制HepG2细胞的增殖,且抑制作用呈时间和剂量依赖性。HepG2细胞经BEZ235处理后,细胞阻滞于G1期,cyclinD1表达水平下调,而cyclinB1的表达则不受影响。BEZ235明显增强了阿霉素对HepG2细胞的抑制作用,并促进阿霉素下调β-catenin的表达。结论 BEZ235对人肝癌细胞HepG2的生长具有显著的抑制作用;联合应用BEZ235和DOX协同抑制HepG2细胞的增殖,其机制可能与共同调节β-catenin通路相关。     

Interaction of celecoxib with different anti-cancer drugs is antagonistic in breast but not in other cancer cells

Celecoxib, an inhibitor of cyclooxygenase-2, is being investigated for enhancement of chemotherapy efficacy in cancer clinical trials. This study investigates the ability of cyclooxygenase-2 inhibitors to sensitize cells from different origins to several chemotherapeutic agents. The effect of the drug's mechanism of action and sequence of administration are also investigated.The sensitivity, cell cycle, apoptosis and DNA damage of five different cancer cell lines (HeLa, HCT116, HepG2, MCF7 and U251) to 5-FU, cisplatin, doxorubicin and etoposide ± celecoxib following different incubation schedules were analyzed.We found antagonism between celecoxib and the four drugs in the breast cancer cells MCF7 following all incubation schedules and between celecoxib and doxorubicin in all cell lines except for two combinations in HCT116 cells. Celecoxib with the other three drugs in the remaining four cell lines resulted in variable interactions.Mechanistic investigations revealed that celecoxib exerts different molecular effects in different cells. In some lines, it abrogates the drug-induced G2/M arrest enhancing pre-mature entry into mitosis with damaged DNA thus increasing apoptosis and resulting in synergism. In other cells, it enhances drug-induced G2/M arrest allowing time to repair drug-induced DNA damage before entry into mitosis and decreasing cell death resulting in antagonism. In some synergistic combinations, celecoxib-induced abrogation of G2/M arrest was not associated with apoptosis but permanent arrest in G1 phase.These results, if confirmed in-vivo, indicate that celecoxib is not a suitable chemosensitizer for breast cancer or with doxorubicin for other cancers. Moreover, combination of celecoxib with other drugs should be tailored to the tumor type, drug and administration schedule.     

Enhancement of therapeutic potential of TRAIL by cancer chemotherapy and irradiation: mechanisms and clinical implications.

Activation of cell surface death receptors by their cognate ligands triggers apoptosis. Several human death receptors (Fas, TNF-R1, TRAMP, DR4, DR5, DR6, EDA-R and NGF-R) have been identified. The most promising cytokine for anticancer therapy is TRAIL/APO-2L, which induces apoptosis in cancer cells by binding to death receptors TRAIL-R1/DR4 and TRAIL-R2/DR5. The cytotoxic activity of TRAIL is relatively selective to cancer cells compared to normal cells. Signaling by TRAIL and its receptors is tightly regulated process essential for key physiological functions in a variety of organs, as well as the maintenance of immune homeostasis. Despite early promising results, recent studies have identified several TRAIL-resistant cancer cells of various origins. Based on molecular analysis of death-receptor signaling pathways several new approaches have been developed to increase the efficacy of TRAIL. Resistance of cancer cells to TRAIL appears to occur through the modulation of various molecular targets. They may include differential expression of death receptors, constitutively active Akt and NFkappaB, overexpression of cFLIP and IAPs, mutations in Bax and Bak genes, and defects in the release of mitochondrial proteins in resistant cells. Conventional chemotherapeutic and chemopreventive drugs, and irradiation can sensitize TRAIL-resistant cells to undergo apoptosis. Thus, these agents enhance the therapeutic potential of TRAIL in TRAIL-sensitive cells and sensitize TRAIL-resistant cells. TRAIL and TRAIL-receptor antibodies may prove to be useful for cancer therapy, either alone or in association with conventional approaches such as chemotherapy or radiation therapy. This review discusses intracellular mechanisms of TRAIL resistance and various approaches that can be taken to sensitize TRAIL-resistant cancer cells.     

J7, a methyl jasmonate derivative, enhances TRAIL-mediated apoptosis through up-regulation of reactive oxygen species generation in human hepatoma HepG2 cells

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/APO2L), a member of the TNF gene superfamily, induces apoptosis upon engagement of cognate death receptors. While TRAIL is relatively non-toxic to normal cells, it selectively induces apoptosis in many transformed cells. Nevertheless, some human hepatoma cells are particularly resistant to the effects of TRAIL. In this study, we show that J7, a novel methyl jasmonate analogue, sensitizes TRAIL-resistant HepG2 human hepatocarcinoma cells to TRAIL-mediated apoptosis. Our results indicate that J7 substantially enhances TRAIL-induced apoptosis, compared with treatment with either agent alone. Combined treatment with J7 and TRAIL effectively induced Bid cleavage, down-regulation of XIAP, cIAP-1 and Bcl-xL, activation of caspases, and cleavage of poly(ADP-ribose) polymerase and phopholipase γ-1. In addition, generation of reactive oxygen species (ROS) showed a significant increase in cells following exposure to J7 in a time-dependent manner. However, the cytotoxic effects induced by co-treatment with J7 and TRAIL were markedly attenuated by caspase inhibitors, indicating an important role for caspases. Administration of N-acetyl cysteine, a scavenger of ROS, also resulted in significant inhibition of apoptosis induced by combinatory treatment with J7 and TRAIL. These results support a mechanism whereby J7 plus TRAIL induces apoptosis of HepG2 human hepatoma cells through a signaling cascade involving a ROS-mediated caspase pathway.     

Amurensin G, a novel SIRT1 inhibitor, sensitizes TRAIL-resistant human leukemic K562 cells to TRAIL-induced apoptosis

Many types of cancer cells remain resistant towards TRAIL-induced cytotoxicity by the blockade of apoptotic signaling cascades. Thus, sensitizers are needed to enhance the effect of TRAIL-based cancer therapies. Although synergistic tumor cell death has been reported when various HDAC inhibitors were administered with TRAIL in a variety of human cancers, the effect of inhibitors of Class III HDAC such as SIRT1 have not been reported. We reported here for the first time that inhibition of SIRT1 augmented the cytotoxic and apoptotic effects of TRAIL on human leukemic K562 cells. Knockdown of SIRT1 or treatment with amurensin G, a potent new SIRT1 inhibitor, up-regulated the levels of DR5 and c-Myc and down-regulated the level of c-FLIP(L/S). Furthermore, knockdown of SIRT1 or treatment with amurensin G augmented the molecular responses to TRAIL, including activation of caspase-8, -9 and -3, PARP cleavage, up-regulation of Bax, and down-regulation of Bcl-2. Amurensin G-enhanced TRAIL-induced apoptosis was abrogated by caspase inhibitor Z-VAD-FMK. These findings suggest that the suppression of SIRT1 with siRNA or amurensin G sensitize the TRAIL-resistant K562 cell to TRAIL-induced apoptosis, possibly by the up-regulation of c-Myc and DR5 surface expression and the down-regulations of c-FLIP and Mcl-1. In addition, amurensin G, a potent new SIRT1 inhibitor, would be used as a sensitizer of TRAIL in TRAIL-resistant leukemic cells.     

川楝素对人肝癌细胞株HepG2生物学行为的影响

目的 观察川楝素对人肝癌细胞株HepG2增殖和凋亡的影响,并研究其诱导凋亡的机制.方法 取人肝癌HepG2细胞株培养后,随机分为对照组(不添加任何药物)、观察组(加川楝素80 mmol/ml),培养细胞24、48、72 h后,酶标仪测定人肝癌HepG2细胞增殖抑制率;流式细胞仪检测人肝癌HepG2细胞周期和凋亡率.结果 两组对肝癌HepG2细胞增殖抑制率差异有统计学意义(x2=5.33,P＜0.05);两组S期、G0/G1期、M/G2期的细胞比率(t=6.31、6.26、6.56,均P＜0.05)、细胞凋亡率差异有统计学意义(x2=6.15,P＜0.05).结论 川楝素可明显抑制人肝癌细胞HepG2的恶性增殖,并诱导肿瘤细胞凋亡.