野生型p53基因促进长春新碱诱导的细胞凋亡

为探讨VCR与p53介导的细胞凋亡的关系,将野生型p53基因导入一个内源性p53基因重组的多药耐药细胞系 KB_V200,经抗性筛选和杂交鉴定获得外源性p53基因稳定表达的转染细胞系KB_V200-p53。VCR处理细胞后,经电镜及荧光显微镜观察表明KB_V200-p53细胞呈现凋亡的典型形态学特征;而流式细胞术结果显示经600nmol·L^-1的VCR作用24h,KB_V200-p53细胞和KB_V200细胞的凋亡百分数分别为42.4%和8.4%。结果提示野生型p53基因能促进VCR诱导的细胞凋亡,肿瘤细胞对VCR的耐药性可能与细胞内p53基因失活有关。     

KB细胞耐药株的建立及其耐药机制的探讨

用对长春新碱(VCR)敏感的KB细胞为亲本,通过诱变剂甲基磺酸乙酯刺激,然后在培养液中加入浓度递增的CVR,得到耐药细胞株KB_V200。此细胞株对VCR的耐受程度约为KB细胞的175倍。对其它抗肿瘤药物如紫杉醇、秋水仙碱和阿霉素等也有不同程度的交叉耐药性。进一步研究表明,KB_V200对³H-VCR的蓄积明显减少,且耐药基因(mdr1)表达增加。钙通道阻滞剂维拉帕米(Ver)可增加KB_V200对³H-VCR的蓄积和对VCR的敏感性。这些结果提示,KB_V200耐药的机制可能是由于mdr1基因表达增加,产生过量的p-糖蛋白,使药物外排增多所致。     

大黄素逆转肿瘤细胞多药抗药性的作用

目的：研究中药成分大黄素的核苷转运抑制活性和对肿瘤细胞多药抗药性的逆转作用。方法：采用［³H］-胸苷掺入法测定核苷转运抑制作用, 采用MTT法检测细胞毒作用, 采用流式细胞术测定P-糖蛋白的功能和表达。 结果：大黄素能抑制小鼠艾氏腹水癌细胞对［³H］-胸苷的跨膜转运,其IC₅₀为9.9　μmol.L^-1。大黄素能增强抗癌药物5-氟尿嘧啶、丝裂霉素和氨甲蝶呤对人肝癌BEL-7402细胞的细胞毒作用并能部分逆转人乳腺癌细胞MCF-7/Adr对阿霉素的抗药性。大黄素增加罗丹明123在MCF-7/Adr细胞中的蓄积并减少其外排,长时间作用降低了P-糖蛋白的表达。结论：大黄素逆转抗药性的作用与抑制核苷转运、降低P-糖蛋白的功能和表达相关。大黄素作为抗肿瘤生化调节剂用于逆转肿瘤细胞多药抗药性的作用值得进一步研究。     

三氧化二砷对胃癌细胞SGC7901多药耐药的逆转作用及其机制

研究三氧化二砷(arsenic trioxide，As₂O₃)对胃癌细胞多药耐药的逆转作用及其机制。逐渐递增长春新碱(VCR)的浓度诱导胃癌细胞株SGC7901产生多药耐药性(SGC7901/VCR)。MTT法测定药物对肿瘤细胞的杀伤作用；Western blotting检测肿瘤细胞内P-糖蛋白(P-gp)、谷胱甘肽S-转移酶(GST-s)表达。结果表明，胃癌SGC7901/VCR细胞对长春新碱(VCR)、5-氟尿嘧啶(5-Fu)及表阿霉素的耐药倍数分别为16.56倍、2.69倍及13.05倍。经As₂O₃预处理24 h后，长春新碱、5-氟尿嘧啶及表阿霉素对SGC7901/VCR的耐药倍数显著下降(P<0.05)。SGC7901/VCR在静息时细胞内P-gp、GST-s蛋白表达显著高于SGC7901。而As₂O₃可使SGC7901/VCR细胞内P-gp、GST-s蛋白表达显著下降，但是对SGC7901无明显作用。从而证实As₂O₃部分逆转SGC7901/VCR的耐药性，其机制可能与P-gp、GST-s蛋白表达降低有关。     

维拉帕米对MDR1基因转染的Swiss-3T3细胞的化疗增敏作用

为进一步了解维拉帕米对抗药性逆转作用的特征,在人MDR1基因转染的Swiss-3T3多药抗药性细胞,观察了维拉帕米逆转幅度与阿霉素抗性水平的关系。各个转染细胞与母细胞相比,阿霉素毒性明显降低。非毒性浓度(3μmol·L^-1)的维拉帕米对阿霉素毒性的增强作用,在转染细胞均高于母细胞,但逆转幅度与抗性水平成反比。Southern杂交显示,转染细胞基因组中有MDR1 cDNA整合。转染细胞的阿霉素蓄积障碍可被维拉帕米纠正。讨论了药物主动转运的饱和现象在维拉帕米增强效应中的作用,以及P-糖蛋白与药物相互作用的方式。     

紫杉烷类多药耐药逆转剂的合成及其逆转耐药活性紫杉烷类多药耐药逆转剂的合成及其逆转耐药活性

目的设计合成一系列新型紫杉烷类化合物并进行逆转多药耐药肿瘤细胞耐药活性的筛选。方法以本所生物合成的紫杉烷，Sinenxan A为原料，合成了10个(I_1～7, II_1,2, III)新的紫杉烷类化合物，其结构经FABMS，2DNMR确证，并对多药耐药癌细胞进行了逆转耐药性的试验。结果9个(I_2～7,II_1,2,III)化合物对多药耐药的人口腔上皮癌细胞KB/V200，能够显著逆转其耐药性，增强抗癌药的活性，其中化合物I₂, I₃, I₄逆转活性明显好于已知对照药Verapamil。结论紫杉烷类化合物作为多药耐药逆转剂有较好的逆转耐药活性，值得进一步研究。     

洛美利嗪逆转K562/ADM细胞多药耐药性

目的研究洛美利嗪(lomerizine,Lom)逆转K562/ADM细胞多药耐药性的作用及机制。方法MTT法检测细胞毒作用,流式细胞仪研究Lom对ADM和长春新碱(vincristine,VCR)的K562/ADM细胞凋亡诱导作用的影响及对罗丹明123(rhodamine 123,Rh123)外排和P-糖蛋白(P-glycoprotein,P-gp)表达的作用。结果Lom明显提高ADM对K562/ADM多药耐药细胞的细胞毒作用及ADM和VCR的凋亡诱导作用,3,10和30 μmol·L^-1 Lom使K562/ADM对ADM的IC₅₀值由79.03 μmol·L^-1分别降至28.14,8.16和3.16 μmol·L^-1。Lom增加胞内ADM的蓄积浓度并抑制Rh123外排;但作用72 h后对K562/ADM细胞P-gp表达无影响。结论Lom通过抑制P-gp的活性逆转K562/ADM细胞的多药耐药性。     

咯萘啶逆转肿瘤多药耐药及其作用机制

目的:利用mdr1~ 的人白血病和乳腺癌多药耐药(MDR)细胞系K562/A02和MCF-7/ADR研究咯萘啶(pyronaridine,PND)对MDR的逆转作用及其机制.方法:采用MTT法、荧光分光光度法、荧光显微镜法、流式细胞仪法和RT-PCR法分别测定PND单独或与阿霉素(DOX)合用,对肿瘤细胞的生长抑制、诱导凋亡、细胞内药物浓度、mdr1基因表达的影响.结果:PND对敏感及耐药细胞均具有生长抑制作用,半数抑制剂量(IC_(50))根据不同细胞在5.10-18.66μmol/L之间;低毒剂量PND显著增强DOX对耐药细胞的细胞毒和诱导凋亡作用,且增加DOX在耐药细胞内的蓄积及减少罗丹明(Rh123)的外排.RT-PCR结果显示,PND对mdr1基因无下调作用.结论:PND可作为第三代P-糖蛋白(P-gp)抑制剂,通过下调P-gp药物外排泵功能而产生强大的逆转MDR效应.     

白藜芦醇及其糖苷白藜芦醇苷与药物外排转运体的相互作用研究

目的：通过多种不同细胞模型研究两种芪类天然化合物白藜芦醇（trans-resveratrol,TR）及白藜芦醇苷（trans-piceid,TP）与多种药物外排转运体间的相互作用。方法：高效液相及荧光分光光度法分别测定细胞内TR、TP及罗丹明123的浓度,MTT比色法测定细胞活性,Western blot法测定P-糖蛋白的表达。结果：P-糖蛋白抑制剂及底物（维拉帕米和罗丹明123）对TR及TP的细胞摄取无影响。多药耐药相关蛋白2抑制剂,丙磺舒可将TR及TP的细胞摄取量分别增加1.3倍和1.6倍。TR及TP能够显著性增加大鼠脑微血管细胞对罗丹明123的摄取及阿霉素在人白血病阿霉素耐药细胞上的毒性,但对人白血病阿霉素耐药细胞上P-糖蛋白的表达没有显著性改变。米托蒽醌在人非小细胞肺癌细胞上的毒性作用不受TR及TP的影响。结论：TR及TP可以抑制P-糖蛋白的外排作用,但其本身不被P-糖蛋白外排,而是被多药耐药相关蛋白2外排。TR及TP对人乳腺癌多药耐药蛋白的外排作用没有影响。     

维拉帕米对抗阿霉素的中国仓鼠卵巢上皮细胞抗药性的逆转作用

非细胞毒性剂量的维拉帕米(Ver)3μg/ml,增强阿霉素(ADM)对抗阿霉素的中国仓鼠卵巢上皮细胞(RC₁)的生长抑制达10倍。用集落形成法测定表明:Ver 3μg/ml能降低RC₁的IC₅₀值,即从1.2μg/ml降至0.08μg/ml,逆转抗药性达15倍。由于Ver增强ADM在RC₁细胞的积累,从而增强ADM对RC₁细胞的毒性,用流式细胞光度计,研究Ver逆转抗药性机制,发现Ver与ADM合用,能阻断RC₁细胞在G₂+M期。     

2—ASG —3—（3‘,5’—双吗啉甲基—4‘—羟基）—苯甲酰吲哚（HWL—12）逆转肿…

AIM: To explore the reversal of multidrug resistance (MDR) by indole derivative HWL-12. METHODS: Cytotoxicity was determined by tetrazolium (MTT) assay. The function of P-gp was examined by Fura 2-AM assay. Cellular accumulation of doxorubicin (Dox) was measured by fluorescence spectrophotometry. RESULTS: HWL-12 10 mumol.L-1 markedly increased Fura-2 accumulation and was 17.2-fold reversal of MDR in MCF-7/ADR cells. The cellular Dox accumulation in MDR cells was increased in the presence of HWL-12 on the MCF-7/ADR cells. No effect was observed for Dox accumulation in the presence of high Ca2+ (addition of CaCl2) or low Ca2+ (addition of egtazic acid). CONCLUSION: HWL-12 has a potent MDR reversal action which was associated with the increase of cellular Dox accumulation in MDR cells and not related with calcium ion concentration.     

Reversal of multidrug resistance of KBV200 cells by triterpenoids isolated from Poria cocos

Multidrug resistance (MDR) of tumor cells is one of the major problems encountered during cancer chemotherapy. In this paper, we isolated eight triterpenoids from Poria cocos and evaluated their effects on reversing MDR of KBV200 cells. Eight triterpenoids increase significantly vincristine-induced cytotoxicity in drug-resistant KBV200 cells at the concentrations of 12.5 μg/mL and 25 μg/mL. Dehydrotumulosic acid showed the best reversal effect: it increased KBV200 apoptosis induced by vincristine and inhibited P-gp function through enhancing the accumulation and retention of fluorescent P-gp substrate rhodamine 123 in KBV200 cells but had no effect on P-gp expression.     

双苄基异喹啉类生物碱粉防己碱与小檗胺逆转多药抗药性的比较研究

比较了2种结构相近的双苄基异喹啉(BBI)生物碱粉防己碱(TTD)、小檗胺(BBM)与维拉帕米(VRP)逆转多药抗药性的作用。结果,TTD,BBM和VRP在多药抗药的MCF-7/Adr和KBv₂₀₀细胞对ADR和VCR均有明显增敏作用,且作用呈剂量依赖性。其中10μmol·L^-1TTD能完全逆转MCF-7/Adr细胞对ADR的抗药性。TTD,BBM和VRP均有增加MCF-7/Adr细胞内阿霉素积累的作用。TTD和BBM在结构上仅有微小差别,但TTD的逆转MDR作用优于VRP10倍,而BBM的作用与VRP相仿。TTD在裸鼠体内MCF-7/Adr实体瘤模型上也证实有明显逆转ADR抗药性的作用。     

R—dl—型维拉帕米调低KBv200肿瘤细胞对长春新碱和多柔比星的多？…

目的：研究Ｒ－型维拉帕米对多药耐药的降低和及其急性动物毒性,并与消旋维闰帕米的相应结果作比较。方法：细胞毒性的测定用ＭＴＴ法;细胞内多柔比星积累的测定用萤光分光光度计法。急性毒性试验用ＢＡＬＢ－ｃ小鼠腹腔注射法。结果：Ｒ－型维拉帕米部分调低ＫＢｖ２００细胞对长春新碱和多柔比星的耐区性,其调低效应与作用肖度和作用时间有关。     

Reversal of P-gp mediated multidrug resistance in-vitro and in-vivo by FG020318

Overexpression of P-glycoprotein (P-gp) by tumours results in multidrug resistance (MDR) to structurally and functionally unrelated chemotherapeutic drugs. Combined therapy with MDR-related cytotoxins and MDR modulators is a promising strategy to overcome clinical MDR. This study was performed to explore the MDR reversal activity of a novel compound 2-[4-(2-pyridin-2-yl-vinyl) phenyl]-4,5-bis-(4-N,N-diethylaminophenyl)-1(H)-imidazole (FG020318) in-vitro and in-vivo. Tetrazolium (MTT) assay was used to evaluate the ability of FG020318 to reverse drug resistance in two P-gp-expressing tumour cell lines, KBv200 and MCF-7/adr. Intracellular doxorubicin accumulation was determined by fluorescence spectrophotometry in MCF-7/adr cell line. The effect of FG020318 on P-gp function was demonstrated by rhodamine 123 (Rh123) accumulation in KBv200 cells. KBv200 cell xenograft models were established to study the in-vivo effect of FG020318 on reversing MDR. FG020318 was not cytotoxic by itself against P-gp expressing KBv200 cells and MCF-7/adr cells and their parental drug-sensitive KB cells and MCF-7 cells. FG020318 could significantly increase the sensitivity of MDR cells to antitumour drugs including doxorubicin and vincristine in MCF-7/adr cells and KBv200 cells, respectively. It was much stronger than the positive control verapamil in reversal of MDR. FG020318 also increased the intracellular accumulation of doxorubicin in a concentration-dependent manner in MCF-7/adr cells, but did not affect the accumulation of doxorubicin in drug-sensitive MCF-7 cells. The Rh123 accumulation in resistant KBv200 cells was also increased by the addition of FG020318, but Rh123 accumulation was not affected by FG020318 in drug-sensitive KB cells. FG020318 potentiated the antitumour activity of vincristine to KBv200 xenografts and was an efficacious modulator in-vivo. Our results suggested that FG020318 was a highly potent, efficacious MDR modulator not only in-vitro but also in-vivo. The reversal of drug resistance by FG020318 was probably related to the increased anticancer drug accumulation and its inhibition of P-gp function of MDR tumour cells.     

Sambutoxin sensitizes K562/ADR to adrimycin by inhibiting expression of P-glycoprotein

OBJECTIVE To investigate the reverse effects of sambutoxin, a representative derivative of 4-hydroxy-2-pyridone with antibacterial, antifungal and antitumor effects, on multidrug resistance(MDR) of K562/ADR cells to adriamycin(ADR) and to elucidate its potential molecular mechanism. METHODS We first investigated the dose-dependent cytotoxic effects of sambutoxin as single treatment on K562 and K562/ADR cells by MTT and CCK-8 assay in order to select the suitable dosage of sambutoxin in the combination treatment. The cytotoxicity of ADR combined with sambutoxin on K562 and K562/ADR cells were also determined by MTT and CCK-8 assays. Then, effects of sambutoxin on the intracellular accumulation of ADR in K562/ADR cells were determined using flow cytometry. The effect of sambutoxin on the efflux function and expression of P-gp in K562/ADR cells was evaluated by Rhodamine123(Rh123) accumulation assay and Western blotting assay respectively. 3 D interactions of human P-gp with sambutoxin, verapamil and adriamycin predicted by docking studies conducted using Sybyl2.1 sofware. Next, the effect of combination treatment of sambutoxin and ADR on the apoptosis of K562/ADR cells was determined by Hoechst 33342 nuclear staining. The expression of the apoptosis related proteins were detected by Western blotting assay. Effect of sambutoxin and ADR on reactive oxygen species(ROS) level in K562/ADR cells was evaluated detected by the DCFH-DA method using fluorescence microscopy and flow cytometry. Effect of sambutoxin and ADR on EGFR/MAPK and PI3 K/AKT/m TOR signaling pathways in K562/ADR cells was evaluated by Western blotting assay. RESULTS Sambutoxin treatment potently enhanced the susceptibility of K562/ADR cells to ADR in a dose manner and the reversal effect was much more prominent in K562/ADR cells. Sambutoxin increased the intracellular accumulation of ADR and Rh123 in K562/ADR cells. Sambutoxin inhibited protein expression of P-gp through Akt/NF-κB pathway in K562/ADR cells. Molecular docking display sambutoxin with P-gp(PDB code:6 QEX) formed two hydrogen bonds with GLN-725 and ASN-721, total Score was 8.29. Co-administration ADR with sambutoxin remarkably increased ADR-induced apoptosis through mitochondrial pathway, including down-regulation of anti-apoptotic protein Bcl-2, up-regulation of proapoptotic protein Bax, up-regulation of cleaved caspase3, and cleaved PARP, augmented ROS in K562/ADR cells. Moreover, ADR combined with sambutoxin could down-regulate the EGFR/MAPK and PI3 K/AKT/m TOR survival pathway in K562/ADR cells. CONCLUSION Sambutoxin reverses MDR of K562/ADR cells to ADR by downregulating P-gp expression and increasing ROS level, as well as, inducing apoptosis. These fundamental findings provide evidence for further clinical research in application of sambutoxin as an assistant agent for chemotherapy of cancer.     

鬼臼毒素衍生物CIP-36诱导KBV200细胞凋亡

目的研究鬼臼毒素衍生物CIP-36对多药耐药人口腔鳞状上皮癌细胞KBV200的抗肿瘤活性及其作用机制。方法MTT法考察CIP-36对KBV200体外增殖的抑制作用;Giemsa染色、DNAladder和流式细胞仪等方法进行细胞凋亡检测;免疫荧光法观察CIP-36对细胞骨架的作用;West-ernblot法检测CIP-36对KBV200细胞P-glycoprotein表达的影响。结果CIP-36对KBV200细胞有明显的抑制作用,IC50值为(2.06±0.38)μmol.L-1,能够诱导细胞产生凋亡小体和DNAladder。流式细胞检测到了细胞凋亡峰,并观察到细胞周期出现S/G2+M期阻滞。Westernblot结果显示P-gp表达降低,并且观察到CIP-36可破坏KBV200细胞的细胞骨架。结论CIP-36可能通过降低P-gp的表达,破坏细胞骨架等多靶点克服KBV200细胞株的多药耐药性。