Characterization and Resistance Mechanisms of A 5-fluorouracilresistant Hepatocellular Carcinoma Cell Line

Purpose: The chemoresistance of human hepatocellular carcinoma (HCC) to cytotoxic drugs, especiallyintrinsic or acquired multidrug resistance (MDR), still remains a major challenge in the management of HCC.In the present study, possible mechanisms involved in MDR of HCC were identified using a 5-fluorouracil (5-FU)-resistant human HCC cell line. Methods: BEL-7402/5-FU cells were established through continuous culturingparental BEL-7402 cells, imitating the pattern of chemotherapy clinically. Growth curves and chemosensitivityto cytotoxic drugs were determined by MTT assay. Doubling times, colony formation and adherence rates werecalculated after cell counting. Morphological alteration, karyotype morphology, and untrastructure were assessedunder optical and electron microscopes. The distribution in the cell cycle and drug efflux pump activity weremeasured by flow cytometry. Furthermore, expression of potential genes involved in MDR of BEL-7402/5-FUcells were detected by immunocytochemistry. Results: Compared to its parental cells, BEL-7402/5-FU cells hada prolonged doubling time, a lower mitotic index, colony efficiency and adhesive ability, and a decreased drugefflux pump activity. The resistant cells tended to grow in clusters and apparent changes of ultrastructuresoccurred. BEL-7402/5-FU cells presented with an increased proportion in S and G2/M phases with a concomitantdecrease in G0/G1 phase. The MDR phenotype of BEL-7402/5-FU might be partly attributed to increaseddrug efflux pump activity via multidrug resistance protein 1 (MRP1), overexpression of thymidylate synthase(TS), resistance to apoptosis by augmentation of the Bcl-xl/Bax ratio, and intracellular adhesion medicated byE-cadherin (E-cad). P-glycoprotein (P-gp) might play a limited role in the MDR of BEL-7402/5-FU. Conclusion:Increased activity or expression of MRP1, Bcl-xl, TS, and E-cad appear to be involved in the MDR mechanismof BEL-7402/5-FU.     

Reversal effect of tyroservatide (YSV) tripeptide on multi-drug resistance in resistant human hepatocellular carcinoma cell line BEL-7402/5-FU

Tyroservatide (YSV) is an active, low-molecular-weight polypeptide that has been shown to have antitumor effects on human hepatocellular carcinoma BEL-7402 cells in vitro and in vivo. Multi-drug resistance (MDR) represents a major obstacle to the success of cancer chemotherapy. To enhance the chemosensitivity of tumor cells, attention has been focused on MDR modulators. In this study, we evaluated the reversal effect of YSV on MDR, and explored its mechanism of action in vitro. Administration of YSV reversed the multi-drug resistance of human hepatocellular carcinoma BEL-7402/5-FU cells significantly. The intracellular accumulation of doxorubicin and Rhodamine-123 (Rh123) were increased, which implied that the function of the P-glycoprotein (P-gp) efflux pump was inhibited by YSV. Moreover, the mRNA and protein expression of multi-drug resistance gene (MDR1) were also decreased by YSV. We observe that lung-resistance protein (LRP) and multi-drug resistance-associated protein (MRP1) each contribute to MDR in BEL-7402/5-FU cells as well. The mRNA and protein expression of LRP were decreased by YSV. No significant change was observed in mRNA expression of MRP1. However, we observe that the MRP1 protein level was reduced after treatment with YSV. These data demonstrate that YSV effectively reverses MDR in BEL-7402/5-FU cells, and that its mechanism of action is associated with the down-regulation of MDR1, MRP1 and LRP expression, as well as the inhibition of P-gp function.     

抗高迁移率族蛋白1中和抗体对肝癌细胞BEL-7402/ADM药物敏感性的影响

目的:探讨抗高迁移率族蛋白1（high mobility group box-1,HMGB1）中和抗体对肝癌细胞药物敏感性的影响及可能机制。方法:采用阿霉素（adriamycin,ADM）小剂量持续诱导法建立肝癌细胞耐药细胞株BEL-7402/ADM。实验分为BEL-7402/ADM组、ADM组及ADM+抗HMGB1中和抗体组,MTT法检测细胞对ADM的敏感性及抗HMGB1中和抗体对细胞的低毒性,Annexin V-FITC流式细胞法检测细胞凋亡情况,酶标法检测Caspase-9、Caspase-3活性,Western-blot方法检测核因子-κB（nuclear factor-κB,NF-κB）亚单位p-p65、Bcl-2蛋白的表达。结果:ADM对亲本株的半数抑制浓度(IC50)为0.23 μg/mL,对肝癌细胞耐药株BEL-7402/ADM的IC50上升至4.07 μg/mL,耐药指数为17.7。联合抗HMGB1中和抗体能明显提升ADM对BEL-7402/ADM细胞增殖抑制率,IC50下降至0.91 μg/mL;加用逆转浓度（19 ng/mL）的抗HMGB1中和抗体组的BEL-7402/ADM细胞凋亡率较单用ADM组的凋亡率明显上升（P＜0.01）。与BEL-7402/ADM组相比,ADM组细胞的Caspase-9、Caspase-3活性有一定程度上升（P＜0.01）,联合抗HMGB1中和抗体作用后,Caspase-9、Caspase-3活性增强则更加明显（P＜0.01）。BEL-7402/ADM组及ADM组间p-p65、Bcl-2表达无显著差异（P＞0.05）,加用抗HMGB1中和抗体处理后,细胞p-p65、Bcl-2表达明显下降（P＜0.01)。结论:抗HMGB1中和抗体对BEL-7402/ADM细胞耐药性有逆转作用,其机制可能与下调NF-κB介导的Bcl-2表达,促进肝癌细胞凋亡有关。     

阿托伐他汀逆转BEL-7402/5-FU细胞多药耐药的体外实验研究

目的:研究阿托伐他汀对人肝癌细胞株BEL-7402/5-FU多药耐药(multi-drug resistance,MDR)的逆转效果及可能的作用机制.方法:MTT法确定阿托伐他汀的逆转作用浓度,检测其对BEL-7402/5-FUMDR的逆转作用;流式细胞仪检测阿托伐他汀对BEL-7402/5-FU细胞内Rho123浓度的影响;免疫组化及Western-blotting检测阿托伐他汀作用后BEL-7402/5-FU细胞中P-gp及Bcl-xl蛋白质的表达水平.结果:浓度小于125 ng/ml的阿托伐他汀对BEL-7402/5-FU细胞无明显抑制作用;阿托伐他汀(10 ng/ml)联合5-FU(FA10)的逆转倍数为单用5-FU的5.49倍,此浓度的阿托伐他汀作用后BEL-7402/5-FU细胞内Rho123的浓度较对照组升高了1.52倍;P-gp蛋白质水平较对照组无明显变化,Bcl-xl蛋白质水平较对照组显著降低.结论:阿托伐他汀对BEL-7402/5-FU细胞的MDR有逆转作用,这可能与其抑制P-gp的功能及Bcl-xl的蛋白质表达水平有关,但具体分子机制尚需进一步的研究.     

索拉非尼联合奥沙利铂对人肝癌ＢＥＬ-７４０２细胞抑制作用的实验研究

目的　探讨索拉非尼联合奥沙利铂对人肝癌ＢＥＬ-７４０２细胞的抑制作用。方法　选取人肝癌细胞株ＢＥＬ-７４０２,用奥沙利铂和索拉非尼单药或联合（含不同给药顺序）作用于细胞,观察最佳抑制效果。ＭＴＴ法检测奥沙利铂和索拉非尼分别对肝癌ＢＥＬ-７４０２细胞的抑制作用并计算半数抑制浓度（ＩＣ_５０）;电镜下观察细胞形态和超微结构的改变;流式细胞仪检测细胞周期分布及细胞凋亡的变化。结果　奥沙利铂单药及联合索拉非尼组ＢＥＬ-７４０２细胞出现Ｓ期、Ｇ２／Ｍ期阻滞,索拉非尼单药组仅出现Ｓ期阻滞。先用奥沙利铂联合组的ＢＥＬ-７４０２细胞凋亡率最高,为（４０.９４±４.６２）％,其次为先用索拉非尼联合组的凋亡率（３０.０２±４.１５）％,联合组的ＢＥＬ-７４０２细胞凋亡率均高于索拉非尼单药组（Ｐ＜０.０５）。结论　人肝癌ＢＥＬ-７４０２细胞体外对索拉非尼和奥沙利铂均高度敏感,两药联合应用对肝癌细胞有协同抑制作用,且先用奥沙利铂联合给药的效果更好。     

卵圆细胞标志分子在肝癌细胞株ＢＥＬ-７４０２中的表达及其意义

目的　探讨肝癌细胞株ＢＥＬ-７４０２的发生与卵圆细胞之间的分子关联及诱导分化前后的变化特征。方法　应用免疫细胞化学和酶细胞化学技术检测卵圆细胞的多种标志分子ＣＫ７、ＣＫ８、ＣＫ１８、ＣＫ１９、ＡＦＰ及ＧＧＴ在人肝癌细胞株ＢＥＬ-７４０２中的表达状态,并观察ＢＥＬ-７４０２诱导分化前后各种标志分子的表达变化特征。结果　ＢＥＬ ７４０２中ＣＫ７、ＣＫ８、ＣＫ１８、ＡＦＰ及ＧＧＴ表达阳性,ＣＫ１９表达阴性,与卵圆细胞向肝细胞分化早期阶段的分子表达谱相似。ＢＥＬ ７４０２诱导分化前后各分子标记物及ＧＧＴ酶活性的表达无明显改变。结论　ＢＥＬ ７４０２与卵圆细胞在分子表达谱上有高度相似性,提示肝细胞癌的发生与卵圆细胞之间存在重要关联。在诱导分化过程中,ＢＥＬ-７４０２标志分子表达水平的变化要晚于其在细胞周期方面的变化。     

反义端粒酶RNA对肝癌细胞黏附和侵袭的影响

目的:探讨人反义端粒酶RNA(human telomerase RNA,hTR)对肝癌细胞系BEL-7402黏附和侵袭的影响及其机制。方法:利用前期实验成功转染端粒酶正、反义RNA基因的肝癌细胞,分为正义转染组(BEL-7402-hTR-EcoRⅠ细胞)、反义转染组(BEL-7402-hTR-BamHⅠ细胞),空白对照组(BEL-7402细胞)。黏附实验和侵袭实验检测反义hTR转染后BEL-7402细胞的黏附和侵袭能力,免疫细胞化学检测整合素β1(integrinβ1,INTβ1)、上皮钙黏蛋白(epithelial cadherin,E-cad)的表达水平,明胶酶谱法检测基质金属蛋白酶(matrix metalloproteinase,MMP)-2、-9的活性变化。结果:与空白对照组和正义hTR转染组相比,反义hTR转染组BEL-7402-hTR-BamHⅠ细胞的黏附、侵袭能力明显减低(0.204±0.029vs0.505±0.037、0.465±0.029,34.80±3.19vs71.47±5.15、69.87±3.11,均P<0.05),INTβ1表达降低(0.153±0.016vs0.385±0.008、0.375±0.014,P<0.05),E-cad表达增强(0.209±0.020vs0.124±0.018、0.134±0.016,P<0.05),MMP-2和MMP-9的活性受到明显抑制(2 054.22±138.52vs3 105.56±329.60、2 923.22±269.08,846.33±104.66vs1 538.89±122.85、1 453.33±126.35,均P<0.05)。结论:人反义端粒酶RNA能明显减低肝癌BEL-7402细胞的黏附、侵袭能力,其机制可能与上调E-cad的表达、下调INTβ1的表达,并抑制MMP-2和MMP-9的活性有关。     

Cyclic AMP inhibition of proliferation of hepatocellular carcinoma cells is mediated by Akt

Cyclic AMP (cAMP), one of the most important intracellular second messengers, has been reported to inhibit proliferation of human hepatocellular carcinoma (HCC) cells via negatively regulating p42/44 mitogen-activated protein kinase. Here, we reported that cAMP inhibited the proliferation of HCC BEL-7402 cells via a novel mechanism. Forskolin, an activator of adenylate cyclase, inhibited fetal bovine serum (FBS)-stimulated BEL-7402 cell proliferation in a dose- and time-dependent manner, along with the inhibition of FBS-stimulated serine/threoine protein kinase Akt (also known as PKB) phosphorylation which is required for Akt activation and this effect was mimicked by 8-Br cAMP. Forskolin also inhibited Akt phosphorylation stimulated by other growth factors such as IGF-1, epidermal growth factor, and insulin. These inhibitions were found not only in BEL-7402 cells, but also in another HCC cell line SMMC-7721 cells. Myr-Akt (myristolated-Akt), a constitutively active Akt which was relatively resistant to cAMP inhibition, conferred BEL-7402 cells resistance to cAMP treatment. However, overexpression of Myr-Akt alone was not sufficient to stimulate BEL-7402 cell proliferation. cAMP inhibited FBS-stimulated Akt phosphorylation in a cAMP-dependent protein kinase-dependent manner. Further studies demonstrated that cAMP inhibited FBS-induced membrane localization of 3-phosphoinositide-dependent kinase 1 (PDK-1) which is a required process for PDK-1 to phosphorylate Akt, but had no significant effect on phosphoinositide 3-kinase activity. These results indicate that cAMP inhibition of proliferation of HCC cells is mediated by Akt and cAMP inhibits Akt activation via blocking membrane localization of PDK-1.     

miRNA-574-5p通过靶基因高温需求因子A1调控肝癌细胞增殖、侵袭、迁移的分子机制

目的探讨微小RNA(mi RNA)-574-5p通过靶基因哺乳动物高温需求因子A1(HTRA1)调控肝癌细胞增殖、侵袭、迁移的分子机制。方法采用实时荧光定量聚合酶链反应(q RT-PCR)、蛋白质印迹法(Western blot)检测正常细胞株L02及肝癌细胞株Hep G2、SMMC-7721、BEL-7402中mi RNA-574-5p、HTRA1的表达水平,采用Western blot检测转染后Hep G2细胞中细胞周期蛋白D1(cyclin D1)、p21、p27、基质金属蛋白酶(MMP)2、MMP9、MMP14蛋白的表达水平,采用噻唑蓝(MTT)法检测细胞增殖情况,采用Transwell实验检测细胞迁移和侵袭能力,采用双荧光素酶实验检测mi RNA-574-5p对HTRA1活性的影响。结果与L02细胞系比较,肝癌细胞系Hep G2、SMMC-7721、BEL-7402中mi RNA-574-5p的表达水平均升高,HTRA1 m RNA和HTRA1蛋白的表达水平均下降(P﹤0.05)。anti-mi RNA-574-5p组Hep G2细胞中mi RNA-574-5p的表达水平明显低于anti-mi RNA-NC组(P﹤0.01)。与anti-mi RNA-NC组比较,anti-mi RNA-574-5p组Hep G2细胞48、72 h的增殖率及cyclin D1、MMP2、MMP9、MMP14蛋白的表达水平均明显降低,迁移、侵袭数目均明显减少,p21、p27蛋白的表达水平均明显升高(P﹤0.01)。pc DNA-HTRA1组Hep G2细胞中HTRA1蛋白的表达水平明显高于pc DNA组(P﹤0.01)。与pc DNA组比较,pc DNA-HTRA1组Hep G2细胞48、72 h的增殖率及cyclin D1、MMP2、MMP9蛋白的表达水平均明显降低,p21蛋白的表达水平明显升高,迁移、侵袭数目均明显减少(P﹤0.01)。双荧光素酶报告实验显示,mi RNA-574-5p+WT-HTRA1组Hep G-2细胞的荧光素酶活性明显低于mi RNA-NC+WT-HTRA1组(P﹤0.01)。mi RNA-574-5p+MUT-HTRA1组Hep G-2细胞的荧光素酶活性与mi RNA-NC+MUT-HTRA1组比较,差异无统计学意义(P﹥0.05)。与anti-mi RNA-574-5p+si-NC组比较,anti-mi RNA-574-5p+si-HTRA1组Hep G2细胞中HTRA1蛋白的表达水平降低,培养48、72 h的肝癌Hep G2细胞的增殖率均升高,cyclin D1、MMP2、MMP9蛋白的表达水平均升高,细胞迁移、侵袭数目均增多,p21蛋白的表达水平降低(P﹤0.05)。结论mi RNA-574-5p通过靶向负调控HTRA1基因调控肝癌细胞的增殖、侵袭、迁移。     

雷氏大疣蛛蛛毒对人肝癌BEL-7402 细胞增殖的抑制作用及其机制的研究

背景与目的蜘蛛毒素抗肿瘤的研究迄今还是未知领域。本研究探讨雷氏大疣蛛(Macrotheleraveni)蛛毒对BEL-7402细胞增殖的抑制作用,进一步探讨其作用机制。方法采用MTT法测定了雷氏大疣蛛蛛毒(10、20、40、80滋g/ml)对BEL-7402细胞增殖作用的影响;采用[3H]-TdR掺入法检测蛛毒加入前后BEL-7402细胞DNA的变化;利用流式细胞光度术(FCM)探讨雷氏大疣蛛蛛毒对BEL-7402细胞凋亡率和细胞周期的影响;利用Westernblot方法进一步检测雷氏大疣蛛蛛毒对细胞周期相关基因c-myc的变化。结果雷氏大疣蛛蛛毒对BEL-7402细胞增殖有较强的抑制作用(P<0.05),IC50为20滋g/ml,时效和量效关系良好。雷氏大疣蛛蛛毒可以抑制BEL-7402细胞DNA的合成。流式细胞仪检测发现经过雷氏大疣蛛蛛毒作用下的BEL-7402细胞凋亡率增加,细胞周期阻滞在G0/G1期。Westernblot方法进一步检测表明雷氏大疣蛛蛛毒作用于BEL-7402细胞72h后,c-myc基因表达减弱。结论雷氏大疣蛛蛛毒就可以抑制人肝癌BEL-7402细胞的增殖和DNA的合成。其药理作用机制可能是除了诱导凋亡外,主要是使细胞周期相关基因c-myc表达减弱,导致细胞周期的变化。     

布洛芬抑制人肝癌细胞BEL-7402生长及机制的初步研究

背景与目的：近来发现,临床上常用的非甾体类抗炎药(non-steroidal anti-inflammatory drugs,NSAIDs)可以降低多种癌症的发病率。布洛芬(ibuprofen)作为一种常用的NSAIDs,对肝癌是否具有抑制作用,国内外鲜有报道。本研究初步探讨布洛芬抑制肝癌细胞BEL-7402的作用,并研究其相关机制。方法：肝癌细胞BEL-7402分为对照组和不同浓度布洛芬处理组,药物处理0、24、48和72 h后用MTT法检测各组细胞增殖抑制率;流式细胞术检测各组细胞的周期分布;细胞分析仪检测各组细胞活力及细胞凋亡;蛋白[质]印迹(Western blot)检测各组细胞增殖性核抗原(PCNA)、细胞周期蛋白(Cyclin D1)、B细胞淋巴瘤/白血病-2 (Bcl-2)和环氧合酶-2(COX-2)蛋白的表达;ELISA法检测细胞培养上清液中前列腺素E₂(PGE₂)蛋白表达水平。结果：布洛芬组中BEL-7402细胞增殖受到抑制,且抑制作用呈时间和剂量依赖性(P<0.05)。2.0 mmol/L布洛芬组48 h细胞活力明显低于对照组［(47.87±5.23)% vs (88.93±5.49)%］,G₀/G₁期细胞比例明显高于对照组［(80.04±3.61)%vs (62.36±8.33)%］,细胞早期凋亡率明显高于对照组［(36.65±10.07)% vs (9.81±6.80)%］,差异有统计学意义(P<0.05)。布洛芬作用于细胞48 h后,PCNA、Cyclin D1、Bcl-2以及COX-2蛋白表达与对照组相比显著减少(P<0.05);细胞培养上清液中PGE₂蛋白表达量与对照组［(23.98±4.89) ng/L vs (68.70±9.43) ng/L］相比,显著降低(P<0.01)。结论：布洛芬能够抑制肝癌细胞BEL-7402增殖与活力,阻滞细胞周期,促进细胞凋亡,其作用机制可能与抑制COX-2及PGE₂表达有关。     

Sorafenib联合紫杉醇不同给药顺序作用于人肝癌细胞BEL-7402的效应

背景与目的：Sorafenib是一种多靶点的抗肿瘤药物,其治疗原发性肝癌的疗效已经初步得到证实。本研究应用Sorafenib与紫杉醇（paclitaxel,TAX）联合．观察两药不同的给药顺序作用于人肝癌细胞BEL-7402的不同效应,初步探讨产生这种差异的机制。方法：采用MTY法检测Sorafenib与紫杉醇单药作用于BEL-7402细胞的IC50流式细胞术检测Sorafenib与紫杉醇不同给药顺序作用后,BEL-7402细胞周期和凋亡率的变化。Western blot检测不同给药顺序作用后的BEL-7402细胞Bcl-2的表达情况。结果：Sorafenib和紫杉醇单药作用于BEL．7402细胞48h的IC50分别为（2.43±0.32） μg/mL、（1.89±0.72） μg/mL。分析Sorafenib、紫杉醇单药,先用紫杉醇再加入Sorafenib,先用Sorafenib再加入紫杉醇及紫杉醇与Sorafenib同时作用后BEL-7402细胞周期及凋亡率的变化,结果显示：①Sorafenib主要将细胞阻滞在S期,而紫杉醇主要将细胞阻滞在G2-M期。②先用紫杉醇再给予Sorafenib组细胞S期及G2-M期均有延长,且较其他组获得较高的凋亡率（36.43±2.29）％（P〈0．01）。Western blot显示先用紫杉醇再给予Sorafenib组BEL-7402细胞的Bcl-2表达的水平最低。结论：Sorafenib联合紫杉醇不同给药顺序作用于BEL-7402细胞,先应用紫杉醇诱导再序贯给予Sorafenib时细胞凋亡率更高：产生这种不同效应的可能机制为两种药物作用于不同的细胞周期,以及不同给药方法后的Bcl-2的表达水平不同。     

几种化疗药物对肝癌耐药细胞BEL7404/ADM端粒酶活性的影响

目的:研究顺铂(DDP)、丝裂霉素(MMC)、多柔比星(ADM)和长春新碱(VCR)4种化疗药物对人肝癌细胞株BEL-7404、耐阿霉素肝癌细胞株BEL-7404/ADM的细胞毒作用及其对端粒酶活性影响的关系。方法:采用MTT法测定常用4种(DDP、MMC、ADM和VCR)化疗药物对人肝癌细胞株BEL-7404、BEL-7404/ADM的体外抑制作用;以TRAP-PCR-ELISA法检测化疗药物作用后两种细胞端粒酶的活性。结果:DDP、MMC、ADM、VCR对BEL-7404均敏感,各种化疗药物IC50大小比较,DDP和ADM比VCR和MMC均小;而对BEL-7404/ADM这几种化疗药物敏感性均不同程度下降,其中以ADM及VCR尤其明显,耐药倍数分别为100·0倍、60·14倍。未加药前,肝癌亲本细胞BEL-7404和耐药细胞BEL-7404/ADM端粒酶活性均表达,加入化疗药物后,亲本细胞端粒酶活性下降明显,并呈现时间-剂量关系,而对于耐药细胞,只有高浓度的化疗药物才能抑制其端粒酶活性。结论:端粒酶活性的抑制与耐药细胞对药物敏感性存在一定关系,端粒酶可作为化疗敏感的潜在标志。     

The study of innate drug resistance of human hepatocellular carcinoma Bel7402 cell line

The innate drug resistance of human hepatocellular carcinoma (HCC) Bel7402 cell line was studied in vitro. MTT assay showed that Bel7402 cells were innately resistant to doxorubicin (Dox), and even more resistant to vincristine (VCR). This resistance could be effectively reversed by verapamil (Ver), one of the classical multidrug resistance (MDR) modulating agents. However, the differences in 5-fluorouracil (5-FU) toxicity between these two cell lines is much less and the resistance of Bel7402 cells could only be slightly reversed by Ver, which may be experimental noise. Immunocytochemical staining using anti-p-glycoprotein monoclonal antibody JSB-1 indicated that the expression of the P-glycoprotein (P-gp) in the innate Bel7402 cells was elevated compared with the sensitive KB cells. The accumulation of Dox in innate resistant Bel7402 cells was 50.7% lower than that in sensitive KB cells by using spectrofluometric analyses, and the accumulation of Dox increased 1.6 fold in Bel7402 cells in the presence of Ver. The susceptibility of Dox-induced apoptosis was also increased in the presence of Ver by using flow cytometric assay and DNA fragmentation quantitative assay as well as by Hoechst 33258 staining. It appears that the innate Bel7402 cells might be useful in screening new antitumour drugs or new chemosensitisers which could overcome the innate or acquired resistant mechanism, and the toxicity and reversal effects with 5-FU are different from those known to be P-gp substrates such as VCR, Dox, and taxol.     

肝癌多药耐药细胞株的建立及其多药耐药机理的研究

 为建立人肝癌多药耐药细胞株并研究其多药耐药的机理，本文应用BEL－7402细胞株，通过不断提高培养液中阿霉素（Doxorubicin）的浓度，长期筛选培养，得到肝癌多药耐药株BEL7402/DoX。经MTT法检测BEL－7402对长春新碱（VCR）等8种抗癌药的抗性提高了27－1100倍不等。以流式细胞技术检测了此细胞株表面MDR1蛋白P－gp、多药耐药相关蛋白MRP及谷胱甘肽硫转移系统（GSH/GST）的表达；用RT－PCR方法检测了MDR及MRP基因表达水平。发现BEL7402/Dox细胞表面P－gp表达为93.5～97.4％；MRP的表达为84.7～90.2％；RT－PCR证实此细胞株中有MDR及MRPmRNA的高表达；未发现GSH/GST的表达升高。     

DC-CIK共培养细胞联合索拉菲尼对肝癌细胞体内外的杀伤效应

目的：观察DC、CIK共培养细胞（DC-CIK）联合索拉菲尼(sorafenib)对肝癌细胞BEL-7402的体内外杀伤效应。方法：取健康人外周血单个核细胞,加入不同细胞因子促进DC及CIK细胞成熟并混合共培养。CCK8试剂盒检测DC-CIK共培养细胞联合索拉菲尼对BEL-7402细胞的体外杀伤效应,Annexin V-FITC试剂盒检测两者联合对肝癌细胞凋亡率的影响。用肝癌细胞BEL-7402建立裸鼠皮下移植瘤模型,分为生理盐水对照组、索拉菲尼组、DC-CIK组、DC-CIK+索拉菲尼组,观察它们对裸鼠移植瘤生长的抑制作用。结果：联合组对肝癌细胞的杀伤率及诱导凋亡率均明显高于各单独治疗组,联合组杀伤率高达（75.24±1.91）%,是DC-CIK组的1.8倍,是索拉菲尼单药组的2.1倍（P<0.01）;联合组诱导肝癌细胞凋亡率达（78.32±2.54）%,与单独治疗组相比差异有统计学意义（P<0.05）。体内实验表明,DC-CIK+索拉菲尼组可明显抑制裸鼠BEL-7402移植瘤的生长,抑制率为（83.37±0.16）%,与单独治疗组相比差异有显著统计学意义（P<0.01）。结论：DC-CIK共培养细胞联合索拉菲尼在体内、外可显著抑制肝癌细胞的生长,分子靶向治疗联合细胞免疫治疗可能成为肝癌综合治疗的方法之一。     

缺氧时5-Fu、As2O3联合及序贯治疗对肝癌细胞凋亡的影响

目的探讨缺氧时5-氟尿嘧啶(5-fluorouracil,5-Fu)和三氧化二砷(As2O3)联合及序贯治疗对肝癌细胞凋亡的影响。方法采用MTT法,分析2种药物联合治疗及序贯治疗对肝癌细胞BEL-7402的细胞毒作用,流式细胞仪检测细胞周期和凋亡情况。结果与单用5-Fu及序贯用药相比,联合用药毒性明显增强,与单用5-Fu相比序贯用药毒性明显增强。联合用药可增加G1期细胞,减少S期细胞,序贯用药可减少G1期细胞,增加S期细胞,且联合用药组细胞凋亡率较高。结论 As2O3、5-Fu可导致细胞凋亡,两者联合有协同作用,与序贯用药相比,联合用药细胞毒作用更强,细胞凋亡率更高,治疗效果更强,实验结果可为临床提供参考依据。     

蜂毒肽突变体Melittin-K1抑制人肝癌细胞BEL-7402生长的作用

目的:为了提高蜂毒肽Melittin的抗肿瘤活性,我们设计出新型多肽并将其命名为Melittin-K1。并对多肽Melittin-K1抑制人肝癌细胞BEL-7402生长的作用进行研究。方法:采用CCK-8法检测细胞活力。扫描电镜拍照结合培养基上清中乳酸脱氢酶（lactic dehydrogenase,LDH）的表达水平来评价细胞膜的损伤水平。构建BEL-7402细胞裸鼠异种移植瘤模型来评价Melittin-K1、Melittin体内对肝癌生长的影响以及毒性。结果:与Melittin相比,Melittin-K1抑制BEL-7402细胞生长的作用更显著;与L02细胞相比,BEL-7402对Melittin-K1的杀伤作用更敏感;Melittin-K1体外抑制BEL-7402细胞生长呈时间、剂量依赖性。扫描电镜以及LDH检测结果均显示Melittin-K1处理组细胞膜的破损情况严重。BEL-7402细胞裸鼠皮下移植瘤模型结果表明,Melittin-K1体内显著抑制肿瘤生长,其抗肿瘤作用明显高于同剂量Melittin。Melittin-K1和Melittin体内毒性小,主要表现在,与模型组相比,体重曲线、肝功指标均未发生明显改变。结论:Melittin-K1能够明显抑制肝癌细胞BEL-7402的增殖,是一种极具潜力的抗肝癌药物。     

切割MDR1 RNA的核酶(Ribozyme)对肝癌多药耐药细胞株BEL-7402/DOX化疗耐药性的逆转作用

为逆转肿瘤多药耐药基因(MDR1)产物P-gp蛋白所介导的肿瘤细胞对多种化疗药物的耐受性,设计合成了一种能切割MDR1 mRNA第196密码子GUC序列的锤头状核酶(Ribozlyme)并定向克隆于转录病毒载体pDOR-neo的BamH Ⅰ位点.经病毒包装细胞PA317包装后感染人肝癌多药耐药细胞株BEL-7402/DOX细胞,经G418筛选得到稳定的转化细胞株.Northem Blot杂交证实包装细胞PA317及转化的BEL-7402/DOX细胞中均有病毒的高表达,RT-PCR证实转化细胞中MDR1 mRNA与未转化细胞相比明显减少甚至不能扩增出来,流式细胞技术检测转化细胞P-gp的表达与非转化细胞的93.4～97.5%相比下降至8.2～14.6%.MTT法检测证实转化细胞对多种化疗药物重新产生较高的敏感性.结果表明,表达Ribozyme的逆转录病毒载体转化肝癌多药耐药细胞BEL-7402/DOX后能有效抑制MDR1的表达和翻译,使已产生耐药的肿瘤细胞的多药耐药表型发生逆转.     

miR-16对人肝癌细胞BEL-7402增殖与凋亡的影响

背景与目的：miR-16和miR-15a基因复合体位于人13q14区域的DLEU2基因内含子内,是目前公认的抑癌基因之一。该基因区域的缺失与多种实体肿瘤有关,miR-16同时促进肿瘤细胞的凋亡。该研究旨在探讨miR-16对BEL-7402肝癌细胞增殖与凋亡的影响。方法：人肝癌细胞BEL-7402分为miR-16感染组(加入LV-hsamiR-16-1慢病毒)和阴性对照组(加入阴性对照病毒),采用倒置荧光显微镜观察细胞绿色荧光的强度;采用细胞计数试剂盒(cell counting kit-8,CCK-8)检测miR-16对BEL-7402肝癌细胞增殖的影响;采用流式细胞术分析miR-16对人肝癌细胞BEL-7402的细胞周期与凋亡的影响。结果：CCK-8检测结果显示,感染组细胞增殖能力明显降低(P<0.05);流式细胞术检测结果显示,阴性对照组BEL-7402细胞周期中G₁期细胞百分率数值明显下降,但S及G₂/M期细胞的百分率均明显上升(P<0.05)。miR-16促进BEL-7402肝癌细胞凋亡。结论：miR-16抑制BEL-7402肝癌细胞的增殖并促进其凋亡,miR-16有望成为临床肝癌靶向治疗的新靶点。