蟾蜍灵通过抑制端粒酶活性诱导人脑胶质瘤细胞死亡

目的:探讨蟾蜍灵对人脑胶质瘤的作用。方法:将不同浓度的蟾蜍灵作用于胶质瘤细胞后,用CCK-8法检测细胞增殖抑制率,克隆形成实验检测细胞法检测增殖抑制,Western-blot测定人端粒酶逆转录酶（hTERT）的蛋白表达,Real time-PCR检测hTERT基因表达水平,CCK-8法检测蟾蜍灵对人原代胶质瘤细胞的杀伤作用。结果:蟾蜍灵对胶质瘤细胞株细胞U251、U87增殖具有抑制作用,且呈时间和剂量依赖性,并且能够有效抑制U251及U87细胞的克隆形成。Western-blot结果显示hTERT蛋白表达随药物浓度增加而递减,Real time-PCR结果证实蟾蜍灵降低了hTERT基因表达。同时体外实验证明,蟾蜍灵对人原代胶质瘤细胞具有明显杀伤作用。结论:蟾蜍灵能够抑制胶质瘤细胞系细胞及人原代胶质瘤细胞增殖,同时通过抑制hTERT表达降低端粒酶活性以发挥其抗肿瘤的作用。     

蟾蜍制剂诱导肿瘤细胞凋亡的研究进展

蟾蜍制剂是我国传统中药材,具有镇痛、消炎、麻醉等作用。近年来研究表明其具有多种抗肿瘤作用,包括诱导细胞凋亡,抑制增殖,促进细胞分化,抑制肿瘤血管形成等作用。而近几年来,以研究蟾蜍制剂诱导肿瘤细胞凋亡作用机制最多,本文主要就近几年来蟾蜍制剂：华蟾素、蟾毒灵及华蟾毒精诱导细胞凋亡作用机制的研究进展做一综述。     

蟾蜍灵诱导NB4细胞凋亡及其分子机制的初步探讨

目的：了解蟾蜍灵（bufalin）诱导对急性旱幼粒细胞白血病（APL）细胞株NB4的增殖抑制和诱导凋亡作用及其分子机制。方法：以急性旱幼粒细胞白血病细胞株NB4细胞为研究对象，应用细胞计数、形态学分析、电镜以及RT—PCR手段．观察蟾蜍灵对NB4细胞的作用。结果：蟾蜍灵以时间、剂量依赖的方式抑制NB4细胞的增殖，并诱导NB4细胞凋亡，同时有效降低NB4细胞中Survivin基因的表达。结论：蟾蜍灵诱导NB4细胞凋亡过程中其可能的分子机制是与Survivin基因表达下调有关。     

蟾蜍灵对人非小细胞肺癌A549细胞增殖与凋亡的影响

背景与目的蟾蜍灵是从中药蟾酥中提取出来的有效成分,其抗肿瘤作用已经在许多体外肿瘤细胞中得到证实,本研究旨在探讨蟾蜍灵对人非小细胞肺癌细胞的增殖抑制、诱导凋亡作用及其机制.方法采用MTT法测定细胞活力,绘制细胞增殖抑制曲线;瑞氏-吉姆萨染色法观察细胞形态学的变化;流式细胞仪通过PI染色进行细胞周期分析及凋亡判定;Western blot法检测Livin及Caspase-3蛋白的表达.结果蟾蜍灵以时间、剂量依赖方式抑制A549细胞增殖,48 h、72 h及96 h抑制细胞增殖50%的药物浓度(half maximal inhibitory concentration,IC50)分别为(56.14±6.72)nmol/L、(15.57±4.28)nmol/L及(7.39±4.16)nmol/L;蟾蜍灵能诱导肺癌细胞凋亡,形态学表现为出现凋亡小体及流式细胞仪榆测到的亚二倍体凋亡峰,凋亡率与对照组比较差异有统计学意义(均P<0.01);蟾蜍灵诱导细胞凋亡过程中,下调Livin蛋白表达(P<0.01),同时活化Caspase-3蛋白.结论蟾蜍灵能够抑制肺癌细胞A549的增殖,并诱导其凋亡;抑制凋亡抑制蛋白Livin的活性及活化Caspase-3可能在其抑癌机制中发挥重要作用.     

蟾蜍灵对人鼻咽癌细胞CNE-1的放射增敏作用

目的:观察蟾蜍灵对鼻咽癌细胞的放射增敏作用。方法:通过MTT法获得单纯蟾蜍灵作用于鼻咽癌细胞CNE-1的细胞存活曲线及抑制细胞增殖50%的药物浓度(IC50),然后采用蟾蜍灵及放射线单独或联合作用于CNE-1细胞,用克隆形成法经SPSS 9.0软件绘制细胞存活曲线,获得不同处理条件下的放射增敏比。结果:单纯用药组,CNE-1细胞的存活率随蟾蜍灵浓度的增加而降低,其IC50约为2.5×10-7mol/L。2.5×10-9和2.5×10-7mol/L的蟾蜍灵作用CNE-1细胞24 h后均见到放射增敏作用,增敏比分别为1.21和1.42。结论:蟾蜍灵对鼻咽癌细胞CNE-1有放射增敏作用,且增敏作用随浓度的增加而增强。     

蟾蜍灵对乳腺癌干细胞增殖和凋亡的影响

目的:探讨蟾蜍灵对乳腺癌干细胞的增殖和侵袭能力的影响。方法:将人乳腺癌MDA-MB-231细胞系进行培养,采用流式细胞分选技术从中分离出乳腺癌干细胞。CCK-8法检测不同浓度的蟾蜍灵对乳腺癌干细胞增殖的影响。流式细胞术Annexin Ⅴ-FITC/PI双染检测不同浓度的蟾蜍灵对乳腺癌干细胞凋亡的影响。结果:成功从MDA-MB-231细胞系中分选出乳腺癌干细胞。CCK-8结果显示,蟾蜍灵呈时间、浓度依赖性抑制乳腺癌干细胞增殖。流式细胞术结果显示蟾蜍灵随时间和浓度增加诱导乳腺癌干细胞凋亡率增加。 结论:蟾蜍灵能够抑制乳腺癌干细胞的增殖,并诱导其凋亡。     

蟾蜍灵诱导人肺腺癌细胞凋亡作用及其机制

目的 研究中药蟾酥有效成分蟾蜍灵(bufalin)对人肺腺癌细胞的作用及其机制。方法 MTT法检测蟾蜍灵对细胞的增殖抑制作用;瑞氏 吉姆萨染色法观察细胞形态学的变化;流式细胞术分析细胞凋亡和线粒体跨膜电位;Western blot法检测Bcl-2、Caspase-3蛋白的表达。结果 (1) 蟾蜍灵明显抑制A549细胞增殖,48h及72h的IC50分别为(56.14±6.72)nmol/L、(15.57±4.28)nmol/L。(2) 蟾蜍灵能诱导肺癌细胞凋亡,形态学表现为出现凋亡小体及流式细胞仪检测到的亚二倍体凋亡峰。(3) 蟾蜍灵可以明显降低细胞线粒体跨膜电位(ΔΨm)。(4) 蟾蜍灵诱导细胞凋亡过程中,下调Bcl-2蛋白表达(P<0.01),同时活化Caspase-3。结论 线粒体途径是蟾蜍灵诱导肺腺癌A549细胞凋亡的主要通路之一。     

蟾蜍灵对B16细胞增殖及凋亡的影响

目的 研究中药蟾蜍灵对B16细胞增殖和凋亡的影响,探讨蟾蜍灵对黑色素瘤的抑制作用。方法 采用MTT法测定蟾蜍灵对B16细胞活力的影响;Hoechst 33342荧光染色检测细胞形态学变化;流式细胞术检测蟾蜍灵对细胞周期的影响。结果 蟾蜍灵对B16细胞的增殖有抑制作用,且呈浓度和时间的依赖性。蟾蜍灵作用24、48和72 h的IC50值分别为37.80、6.00和9.12 μmol/L。荧光染色显示蟾蜍灵作用于B16细胞24 h后,细胞呈现典型的凋亡形态特征;细胞周期分析显示,蟾蜍灵处理组S期细胞降低,蟾蜍灵可引B16细胞G0/G1期阻滞,而对G0/G1期阻滞随作用时间延长而增强。结论 蟾蜍灵可能通过阻滞B16细胞增殖周期进程而诱导凋亡。     

蟾蜍灵在诱导K562细胞凋亡过程中下调TOPO-Ⅱα蛋白表达

目的探讨蟾蜍灵(bufalin)诱导K562细胞凋亡的分子机制。方法用流式细胞仪和形态学检测细胞凋亡;用免疫组化SP法检测TOPO-Ⅱα蛋白表达。结果蟾蜍灵在诱导K562细胞凋亡过程中,下调TOPO-Ⅱα蛋白表达;细胞外信号转导激酶抑制剂(extra-cellularsignal-regulatedkinase,ERK)PD98059能协同蟾蜍灵下调TOPO-Ⅱα蛋白表达;而四癸酰佛波酯(TPA)却拮抗蟾蜍灵的作用。结论蟾蜍灵诱导K562细胞凋亡可能与抑制ERK信号途径以及下调TOPO-Ⅱα蛋白表达有关。     

抑制NF—κB通路增强蟾蜍灵诱导的HL-60细胞凋亡

目的：观察蟾蜍灵对HL-60细胞活力和凋亡的影响,对NF—κB通路的作用,探讨NF—KB通路在蟾蜍灵诱导HL-60细胞凋亡过程中的作用。方法：锥虫蓝染色检测细胞活力;流式细胞仪技术检测细胞凋亡和周期分布;采用WesternBlot技术检测IKK的磷酸化。结果：蟾蜍灵以时间和剂量依赖性方式诱导HL-60细胞凋亡。24,48和72h抑制细胞活力的Ic50浓度分别为26．3,7．8和2．0nmol／L。对照组HL-60细胞有pIKK表达,蟾蜍灵可诱导IKK的快速活化。NF—κB通路的特异性抑制剂Bay11—7082增强蟾蜍灵的凋亡诱导作用。结论：蟾蜍灵可诱导HL-60细胞凋亡,促进IKK活化与NF—κB通路调节相关,而且与NF—κB通路抑制剂有协同作用。     

Anti-cancer mechanism of bufalin

Bufalin is one of the major active components of Chan Su, a traditional Chinese medicine. Studies at home and abroad have confirmed that bufalin can inhibit cell proliferation significantly in many human leukemia and solid cancer cell lines by inhibiting endothelial hyperplasia and angiogenesis, and inducing cell differentiation and apoptosis. With the deepening of study，it is showed that bufalin has extensive anticancer activities and it has potential clinical value with very low drug concentration.     

Bufalin exerts antitumor effects by inducing cell cycle arrest and triggering apoptosis in pancreatic cancer cells

As one of the most aggressive human malignancies, pancreatic cancer is a leading cause of cancer-related deaths worldwide and only about 4 % of patients will live 5 years after diagnosis. Eighty to approximately eighty-five percent of patients are diagnosed with an unresectable or metastatic disease, which is correlated with poor prognosis and low survival rate. Therefore, it is tremendously significant to exploit novel chemicals to prevent and treat pancreatic cancer. Previous research and clinical studies have demonstrated that many natural products derived from traditional Chinese medicine (TCM) such as camptothecin derivatives and vinca alkaloids could be effective antitumor compounds, hinting that TCM is a promising source for developing new antitumor drugs. In this report, we investigated the effects of bufalin, a primary active ingredient of the traditional Chinese medicine Chan-Su, on pancreatic cancer cell lines PANC-1 and CFPAC-1 and studied the underlying molecular mechanism. We found that exposure to bufalin could suppress the proliferation of pancreatic cancer cells time and dose dependently. We used flow cytometry to study the effects of bufalin on apoptosis and cell cycle distribution in PANC-1 and CFPAC-1 cells. The results indicated that bufalin could significantly induce both apoptosis and G2/M cell cycle arrest in pancreatic cancer cells. With western blotting, we found that the expression level of an antiapoptotic protein heat shock protein 27 (Hsp27) and its partner molecule p-Akt was decreased upon the treatment with bufalin. Besides, bufalin activated pro-caspase-3 and pro-caspase-9 and modulated the expression level of Bcl-2 and Bax. These data suggested that bufalin may trigger apoptosis by targeting Hsp27, which could inhibit apoptosis by interfering with key apoptotic proteins. The influence on the level of cylinB1, CDK1, and p21 was also observed after bufalin treatment, and the relationship between Hsp27 and the cell cycle-related proteins mentioned above deserves much more research. In addition, our data showed that bufalin could enhance the growth inhibition effect of gemcitabine in above pancreatic cancer cells. Taken together, bufalin might be worthy of further study for its potential as a therapeutic agent for pancreatic cancer treatment.     

Bufalin induces apoptosis through activation of both the intrinsic and extrinsic pathways in human bladder cancer cells

Bufalin, a major digoxin-like immunoreactive component of the Chinese medicine Chansu, is prepared from toad venom. This compound has been shown to exert a potential for anticancer activity against various human cancer cell lines in?vitro. However, the detailed molecular mechanisms of its induction of apoptosis are still unclear. In this study, we investigated the apoptosis-inducing effect of bufalin in T24 human bladder cancer cells. Our data revealed that bufalin treatment resulted in a concentration-response growth inhibition of T24 cells by inducing cell cycle arrest at the G2/M phase and apoptosis, as evidenced by formation of apoptotic bodies, chromatin condensation and accumulation of cells in the sub-G1 phase. Apoptosis induction of T24 cells by bufalin showed correlation with proteolytic activation of caspase-3, -8 and -9, and concomitant degradation of poly (ADP-ribose) polymerases, and collapse of the mitochondria membrane potential. In addition, bufalin treatment resulted in an increase of the Bax/Bcl-2 (or Bcl-xL) ratio and caused down-regulation of inhibitor of apoptosis protein (IAP) family members. The increase in apoptosis by bufalin treatment was also associated with up-regulation of death receptor-related factors. Our data indicate that the growth inhibitory effects of bufalin occur through blockade of the G2/M phase, and that these cancer cells do not enter cell cycle progression and die through apoptosis via both intrinsic and extrinsic pathways.     

Na+/K+-ATPase α3 mediates sensitivity of hepatocellular carcinoma cells to bufalin

Bufalin, a major bioactive component of the Chinese medicine Chansu, has been reported to exhibit significant antitumor activity against various cancer cell lines. However, the exact mechanism remains unclear. In this study, we demonstrated that bufalin inhibited the growth of hepatocellular carcinoma (HCC) cells in a dose-dependent manner, which correlated with the expression level of Na+/K+-ATPase α3 in HCC cells. The IC50 of bufalin markedly increased when Na+/K+-ATPase α3 was silenced by RNA interference. Furthermore, we show that bufalin increased the phosphorylation of Akt and ERK1/2 while inhibited FoxO3a expression. Thus, our study suggests that Na+/K+-ATPase α3 might serve as a therapeutic target for bufalin in HCC, and its expression status may help predict sensitivity of HCC cells to bufalin treatment.     

Anti-tumor Activity and Apoptosis-regulation Mechanisms of Bufalin in Various Cancers: New Hope for Cancer Patients

The induction of apoptosis in target cells is a key mechanism for most anti-tumor therapies. Bufalin is acardiotonic steroid that has the potential to induce differentiation and apoptosis of tumor cells. Research onbufalin has so far mainly involved leukemia, prostate cancer, gastric cancer and liver cancer, and has beenconfined to in vitro studies. The bufadienolides bufalin and cinobufagin have been shown to induce apoptosis ina wide spectrum of cancer cell. The present article reviews the anticancer effects of bufalin. It induces apoptosisof lung cancer cells via the PI3K/Akt pathway and also suppressed the proliferation of human non-small celllung cancer A549 cell line in a time and dose dependent manner. Bufalin, bufotalin and gamabufotalin, keybufadienolides, significantly sensitize human breast cancer cells with differing ER-alpha status to apoptosisinduction by the TNF-related apoptosis-inducing ligand (TRAIL). In addition, bufadienolides induce prostatecancer cell apoptosis more significantly than that in breast epithelial cell lines. Similar effects have been observedwith hepatocellular carcinoma (HCC) but the detailed molecular mechanisms of inducing apoptosis in this caseare still unclear. Bufalin exerts profound effects on leukemia therapy in vitro. Results of multiple studies indicatethat bufalin has marked anti-tumor activities through its ability to induce apoptosis. Large-scale randomized,double-blind, placebo or positive drug parallel controlled studies are now required to confirm the efficacy andapoptosis-inducing potential of bufalin in various cancers in the cliniucal setting.     

MicroRNA-497 and bufalin act synergistically to inhibit colorectal cancer metastasis

The study aims to investigate the effect of microRNA-497 (miR-497) expression and bufalin treatment in regulating colorectal cancer invasion and metastasis. The expression of miR-497 in colorectal cancer cells with prior treatment with bufalin was determined using real-time quantitative PCR. The nude mouse abdominal aortic ring assay and the human umbilical vein endothelial cell (HUVEC) migration assays were used to measure the angiogenic effect of bufalin. The effect of both bufalin treatment and miR-497 overexpression on colorectal cancer metastasis was measured using an animal tumor model together with in vivo imaging. These results suggested: (1) In the HCT116 cells and HUVECs, proliferation was inhibited in a time-dependent and/or concentration-dependent manner following the administration of bufalin; (2) Bufalin inhibited cell migration in a concentration-dependent manner by cell motility assays; (3) In the aortic ring assay, administration bufalin to the aortic ring significantly promoted micro-angiogenesis of nude mouse abdominal aorta in a concentration-dependent and time-dependent manner; (4) miR-497 was upregulated in human colorectal cancer HCT116 cells treated with different concentrations of bufalin in a concentration-dependent manner; and (5) Combined application of bufalin and miR-497 significantly reduced metastatic lesions and reduced weight loss compared with bufalin alone and control groups in vivo. This study revealed that bufalin inhibited angiogenesis and regulated miR-497 expression and that bufalin and miR-497 acted in synergy to inhibit colorectal cancer metastasis, resulting in improved quality of life in a nude mouse model.     

蟾毒灵对人骨肉瘤细胞化疗增敏作用的实验研究

目的 探讨蟾毒灵对人骨肉瘤细胞Saos 2和U2OS的化疗增敏作用。方法 采用无毒剂量的蟾毒灵联合不同浓度的阿霉素（0.01、0.1、1.0μg／ml ADM）和顺铂（0.5、1.0、2.0μg／ml DDP）分别作用于Saos-2和U2OS细胞24h,用CCK-8法观察药物对细胞增殖的抑制作用,Hoechst 33258 染色法观察细胞凋亡的形态学改变,流式细胞术检测细胞凋亡率。结果CCK-8法检测显示,蟾毒灵对Saos 2和U2OS细胞增殖的抑制作用呈浓度依赖性;无细胞毒剂量（0.005μmol／L）的蟾毒灵可以显著增强不同浓度ADM和DDP 对Saos-2和U2OS细胞增殖的抑制作用（q＞1.15）。Hoechst 33258染色法显示,蟾毒灵联合DDP或ADM后Saos-2和U2OS细胞的凋亡形态学变化较DDP或ADM单药更显著。流式细胞术检测显示,0.005μmol／L蟾毒灵联合1.0μg／ml DDP或2.0μg／ml ADM组Saos-2和U2OS细胞的凋亡率显著高于DDP或ADM单药组（q＞1.15,P＜0.05）。结论 无毒剂量的蟾毒灵可以增强化疗药物诱导的人骨肉瘤细胞凋亡的能力,具有化疗增敏作用。     

A cardiotonic steroid bufalin-like factor in human plasma induces leukemia cell differentiation

A Na⁺,K⁺-ATPase inhibitor, bufalin, has been shown previously to induce leukemia cell differentiation. The presence of a circulating Na⁺,K⁺-ATPase inhibitor has been proposed in mammals. The aim of this study was to explore an endogenous bufalin-like factor that induces leukemia cell differentiation. We found a fraction, designated as fraction A, obtained from human plasma extract that inhibits the growth of several human-derived leukemia cell lines. The effect of the fraction was retained after protease digestion or heat treatment. Murine leukemia cells and ouabain-resistant cells, which are insensitive to bufalin, appeared to be refractory to fraction A in terms of growth inhibition. Fraction A also induced functional and morphological maturation in THP-1 cells. Fraction A was recognized by anti-bufalin anti-serum and inhibited ³H-bufalin binding to K562 cells. These findings suggest that fraction A shows a similar behavior to that of bufalin on leukemia cells by inhibiting Na⁺,K⁺-ATPase. We propose that an endogenous Na⁺,K⁺-ATPase inhibitor in human plasma may play a role in cell differentiation.