基因mdr1高表达多药耐药肿瘤细胞对力达霉素的药物敏感性

目的利用经药物诱导获得的mdr1基因高表达细胞株以及通过mdr1基因转染建立的稳定高表达细胞株，研究多药耐药肿瘤细胞对力达霉素(C-1027)的药物敏感性。方法构建mdr1重组真核表达质粒pcDNA3.1/mdr1，利用脂质体转染技术，获得mdr1高表达HepG2肝癌细胞。经RT-PCR、细胞荧光免疫化学及罗丹明外排实验，鉴定了细胞的mdr1表达水平和药物外排活性。MTT方法测定敏感细胞及相对应的多药耐药细胞对力达霉素等多种抗肿瘤药物的药物敏感性。结果mdr1稳定转染细胞株HepG2/mdr1、多药耐药KBv200细胞和MCF-7/ADR细胞对力达霉素的IC₅₀值分别为(0.020±0.011) nmol·L^-1，(0.24±0.20) nmol·L^-1和(0.028±0.011) nmol·L^-1。相对于各自的敏感细胞，多药耐药细胞HepG2/mdr1，KBv200和MCF-7/ADR对力达霉素的抗药倍数分别是1.3，6.8和1.6倍，对阿霉素的抗药倍数分别是8.8， 37.2和181.3倍，对紫杉醇的抗药倍数分别是40.3， 336.8和49.2倍。结论 mdr1高表达的多药耐药肿瘤细胞对力达霉素仍高度敏感，未表现出抗药性。     

Adenovirus-mediated p53 gene therapy reverses resistance of breast cancer cells to adriamycin

The aim of this study was to determine whether adenovirus-mediated p53 gene (Ad-p53) transfection can enhance adriamycin cytotoxicity and reverse adriamycin resistance in human breast cancer cells and explore its effect on the expression of MDR1 gene and permeability-glycoprotein (P-gp). Human breast cancer cell lines, MCF-7 and MCF-7/ADR, were used in in-vitro studies. After infection with Ad-p53, the cytotoxicity of adriamycin was evaluated using the Cell Counting Kit-8 assay. The expression of MDR1 mRNA was detected by quantitative real-time PCR. The expression of P-gp was analyzed using western blotting. In in-vivo studies, MCF-7/ADR tumor cells were inoculated subcutaneously in athymic nude mice. After 14 days of inoculation, tumor size was measured. Apoptosis and expression of P-gp in the tumor tissue were analyzed by fluorescence activated cell sorting and western blotting. After transfection with a multiplicity of infection of 50 for Ad-p53, chemosensitivity of MCF-7/ADR cells increased by 18.1 times (P=0.001), and 50% inhibitory concentration (IC50) of adriamycin decreased from 4.54 ± 0.91 to 0.26 ± 0.11 mg/l. Real-time PCR showed that MDR1 mRNA decreased from 1.32 to 0.85 (P=0.001). Western blotting analysis showed that P-gp also decreased. In in-vivo studies, Ad-p53 combined with adriamycin dramatically inhibited the growth of subcutaneous xenograft of MCF-7/ADR. The fluorescence activated cell sorting assay showed that there were more apoptotic cells in tumor tissues treated with Ad-p53 and adriamycin. The expression of P-gp was significantly decreased in tumor tissues. This study suggests that Ad-p53 can reverse MCF-7/MDR cell resistance to adriamycin. The reversal effect was associated with inhibition of P-gp expression and induction of apoptosis.     

粉防己碱逆转肿瘤多药抗药性细胞的凋亡抗性作用

目的探讨粉防己碱逆转ＭＤＲ细胞凋亡抗性的作用及其机制。方法ＭＤＲ细胞株ＭＣＦ－７／Ａｄｒ与其相应的敏感株ＭＣＦ－７进行对比研究。比较粉防己碱对阿霉素（Ｄｏｘ）诱导ＭＤＲ细胞及其相应的敏感株的凋亡作用。并比较粉防己碱对ＭＤＲ细胞及其相应的敏感株的细胞ｂｃｌ－２蛋白的表达的影响。细胞凋亡及ｂｃｌ－２蛋白表达的测定以流式细胞仪法。结果加入Ｄｏｘ共同培养２４ｈ可诱导７４．６％ＭＣＦ－７细胞凋亡，而只引起１４．３％的ＭＣＦ－７／Ａｄｒ细胞凋亡。只加入粉防己碱共同培养２４ｈ，未见明显增加ＭＤＲ细胞及其相应敏感细胞的凋亡百分比。Ｄｏｘ＋粉防己碱能显著地使ＭＤＲ细胞的凋亡增至４７．０％，与单独用Ｄｏｘ组相比较，差异有显著性（Ｐ＜０．０１），而敏感细胞株为７７．８％，与单独用Ｄｏｘ组相比较，差异无显著性（Ｐ＞０．０５）。ＭＤＲ细胞株与其相应的敏感株ｂｃｌ－２蛋白表达水平均较低且差异无显著性。加入粉防己碱对ＭＤＲ细胞株与其相应的敏感株ｂｃｌ－２蛋白表达水平均未见明显影响。结论粉防己碱能逆转ＭＤＲ细胞对Ｄｏｘ的凋亡抗性。其逆转机制可能与ｂｃｌ－２蛋白表达无关。粉防己碱逆转ＭＤＲ细胞ＭＣＲ－７／ＡＤＲ对Ｄｏｘ的凋亡抗性的机制有待进?     

Snail增强乳腺癌细胞MCF-7中P-gp介导的多药耐药

目的探讨乳腺癌细胞中Snail过表达与P-gp之间的关系,揭示EMT对乳腺癌细胞多药耐药的影响。方法构建Snail真核表达载体pCDNA3.1-Snail,将载体转染人乳腺癌细胞MCF-7后用阿霉素对细胞进行诱导。利用细胞毒性实验(MTT)、阿霉素外排实验对耐药细胞系的耐药状况进行评价;通过流式细胞术和Real-time PCR分别测量耐药细胞系中P-gp和MDR1 mRNA,Snail mRNA的表达。结果由细胞毒性实验和阿霉素外排实验的结果显示,MCF-7/Snail细胞经阿霉素诱导后相对耐药指数升高至109.2,细胞内荧光强度降至7.1(P<0.05);Real-time PCR显示相对于MCF-7,MCF-7/Snail细胞中的MDR1 mRNA,Snail mRNA的表达明显升高与流式细胞术显示的P-gp升高相一致。结论转染Snail真核表达载体后,MCF-7/Snail细胞的耐药性较MCF-7细胞明显升高。     

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。     

Molecular analysis of MEN1 expression in MCF7, T47D and MDA-MB 468 breast cancer cell lines treated with adriamycin using RT-PCR and immunocytochemistry

Background and the purpose of the study

MEN1 is an important tumor suppressor gene that encodes a nuclear protein called menin. Recent data suggest that interactions between menin and other proteins have important roles in control of the cell cycle and apoptosis. In addition, estrogen receptor (ER), an important prognostic factor is differentially expressed in breast cancer cells. In this study the MEN1 gene and protein expression in MCF7, T47D and MDA-MB-468 breast cancer cell lines with different ER status following exposure to adriamycin (ADR) was investigated.

Materials and methods

Cytotoxicity of ADR on these cell lines was determined using MTT assay. The mRNA and protein levels were analyzed in tested cell lines using RT-PCR and immunocytochemistry (ICC) assays, respectively.

Results

ADR cytotoxicity was highest on MDA-MB-468 and lowest on MCF7 cells. MEN1 mRNA showed significant decrease after ADR exposure only in the MDA-MB-468 cell line. Menin protein expression was higher in MDA-MB-468 and lower in MCF7 cells.

Conclusion

Differential molecular responses to adriamycin were observed in cancer cell lines. Molecular data also suggest that MEN1 as a new biomarker can be used in combination with current biomarkers for prediction of response to chemotherapy.     

Role of differential drug uptake, efflux, and binding of etoposide in sensitive and resistant human tumor cell lines: implications for the mechanisms of drug resistance

In order to study the mechanism of etoposide (VP-16) resistance in human tumor cells and to assess the role of P-170 glycoprotein in VP-16 accumulation, we have examined the uptake and efflux of VP-16 in both sensitive and multidrug-resistant MCF-7 human breast and HL60 human promyelocytic leukemia cells. The drug-resistant cells, MCF-7/ADR and HL60/ADR, were selected for resistance to adriamycin and were 200- to 250-fold resistant to VP-16. Whereas MCF-7/ADR cells overexpress the P-170 glycoprotein and show the multidrug-resistant phenotype, HL60/ADR cells do not overexpress the P-170 glycoprotein. Although there was a 2-fold decrease in accumulation of VP-16 in MCF-7/ADR cells, this decrease did not correlate with a 250-fold resistance to the drug. VP-16 efflux was rapid and almost complete from MCF-7 cell lines and it was decreased at 4 degrees. Further, there was a significant increase in VP-16 accumulation in the MCF-7/ADR cells in the presence of glucose-free medium supplemented with sodium azide. However, no change in the pattern of VP-16 efflux was observed. Under these conditions, addition of glucose caused release of VP-16 from MCF-7/ADR cells, suggesting energy-dependent modifications in the drug binding. Coincubation of vincristine with VP-16 also increased the drug accumulation and decreased the rate of efflux of VP-16 in both sensitive and resistant MCF-7 cells, suggesting that vincristine and VP-16 may compete for similar binding and efflux mechanisms in these cell lines. In contrast, daunorubicin increased VP-16 accumulation only in the sensitive MCF-7 cell line, whereas the efflux rate of VP-16 was not significantly changed in either cell line. HL60 sensitive cells accumulated 4- to 5-fold more VP-16 than the resistant subline. Both sensitive and resistant cells showed an important noneffluxable pool of the drug, 3-fold larger for sensitive cells (79 +/- 12 versus 25 +/- 2 pmol of VP-16/mg of protein, for sensitive and resistant cells, respectively). The efflux of VP-16 was temperature dependent only in sensitive cells. VP-16 accumulation in HL60/ADR cells was increased in glucose-free medium supplemented with sodium azide; however, the noneffluxable pool of VP-16 was not significantly changed. In contrast, although these conditions had no effect on the drug accumulation in the parental line, they caused a decrease in the noneffluxable pool of VP-16, suggesting an energy-dependent binding and retention of VP-16.(ABSTRACT TRUNCATED AT 400 WORDS)     

人参皂苷Rh2逆转MCF-7/ADM多药耐药性的研究

目的观察人采用人参苷Rh2对逆转人乳腺癌多药耐药细胞株MCF-7/ADM的分子机制。方法采用MTT比色法对不同浓度下人参皂苷Rh2对MCF-7/ADM的阿霉素(ADM)以及氟尿嘧啶(Fu)耐药逆转指标检测,同时使用多功能酶标仪检测人参皂苷Rh2干预对细胞内罗丹明123荧光强度以反映其对细胞多药耐药蛋白P-gp活性的影响。结果经过人参皂苷Rh2的干预,MCF-7/ADM对ADM以及Fu两种临床常用化疗的敏感性增强。另外,人参皂苷Rh2还对细胞的罗丹明123外排有显著的浓度依赖性抑制作用。结论人参皂苷Rh2能够有效逆转MCF-7/ADM多药耐药性,其作用机制可能主要为抑制了细胞多药耐药蛋白P-gp的活性。     

米非司酮对乳腺癌细胞系MCF-7/ADM裸鼠移植瘤耐药逆转作用

目的：探讨米非司酮对乳腺癌细胞系MCF-7/ADM裸鼠移植瘤耐药逆转作用。方法：以人乳腺癌细胞系MCF-7/ADM建立耐阿霉素人乳腺癌裸鼠皮下移植瘤动物模型,将成瘤裸鼠随机分为空白对照组,米非司酮组（MIF组）,阿霉素组（ADM组）,米非司酮联合阿霉素组（MIF＋ADM组）。测量裸鼠移植瘤横径与短径,计算移植瘤体积,绘制生长曲线。结果：对裸鼠干预处理4周后,MIF＋ADM组移植瘤体积[（232.5149±309.2377）mm3]最低,ADM组[（508.9648±16.2609）mm3]次之,均低于空白对照组移植瘤体积[（962.2309±261.1313）mm3],差异有统计学意义（P〈0.05）;MIF＋ADM组移植瘤体积较单独用药的MIF组及ADM组低,差异具有统计学意义（P〈0.05）。结论：米非司酮有逆转乳腺癌细胞MCF-7/ADM裸鼠移植瘤耐药性的作用。     

Induction of the liver cancer-down-regulated long noncoding RNA uc002mbe.2 mediates trichostatin-induced apoptosis of liver cancer cells

Differential expression of long non-coding RNAs (lncRNAs) plays critical roles in hepatocarcinogenesis. Considerable attention has focused on the antitumor effect of histone deacetylase inhibitor (Trichostatin A, TSA) as well as the coding gene expression-induced apoptosis of cancer cells. However, it is not known whether lncRNA has a role in TSA-induced apoptosis of human hepatocellular carcinoma (HCC) cells. The global expression of lncRNAs and coding genes was analyzed with the Human LncRNA Array V2.0 after 24 h treatment. Expression was verified in cell lines and tissues by quantitative real-time PCR. The data showed that 4.8% (959) of lncRNA and 6.1% (1849) of protein coding gene were significantly differentially expressed. The differential expressions of lncRNA and protein coding genes had distinguishable hierarchical clustering expression profiling pattern. Among these differentially expressed lncRNAs, the greatest change was noted for uc002mbe.2, which had more than 300 folds induction upon TSA treatment. TSA selectively induced uc002mbe.2 in four studied HCC cell lines. Compared with normal human hepatocytes and adjacent noncancerous tissues, uc002mbe.2 expression level was significantly lower in the HCC cell lines and liver cancer tissues. The TSA-induced uc002mbe.2 expression was positively correlated with the apoptotic effect of TSA in HCC cells. In addition, knockdown the expression of uc002mbe.2 significantly reduced TSA-induced apoptosis of Huh7cells. Therefore, TSA-induced apoptosis of HCC cells is uc002mbe.2 dependent and reduced expression of uc002mbe.2 may be associated with liver carcinogenesis.     

Saikosaponin A,an active glycoside from Radix bupleuri,reverses P-glycoprotein-mediated multidrug resistance in MCF-7/ADR cells and HepG2/ADM cells

1.?The expression and function of P-glycoprotein (P-gp) is associated with the phenotype of multidrug resistance (MDR). Saikosaponin A (SSA) is a triterpenoid saponin isolated from Radix Bupleuri. This study was mainly designed to understand effects of SSA on MDR in MCF-7/ADR and HepG2/ADM cells.

2.?MDR reversal was examined as the alteration of cytotoxic drugs IC50 in resistant cells in the presence of SSA by MTT assay, and was compared with the non-resistant cells. Apoptosis and uptake of P-gp substrates in the tumor cells were detected by flow cytometry. Western blot was performed to assay the expression of P-gp.

3.?Our results demonstrate SSA could increase the chemosensitivity of P-gp overexpressing HepG2/ADM and MCF-7/ADR cells to doxorubicin (DOX), vincristine (VCR) and paclitaxel. SSA promoted apoptosis of MCF-7/ADR cells in the presence of DOX. Moreover, it could also increase the retention of P-gp substrates DOX and rhodamine 123 in MCF-7/ADR cells, and decrease digoxin efflux ratio in Caco-2 cell monolayer. Finally, a mechanistic study showed that SSA reduced P-gp expression without affecting hydrolytic activity of P-gp.

4.?In conclusion, our findings suggest that SSA could be further developed for sensitizing resistant cancer cells and used as an adjuvant therapy together with anticancer drugs to improve their therapeutic efficacies.     

干扰素与维拉帕米逆转乳腺癌细胞耐药作用的研究

目的:研究α-干扰素与维拉帕米对体外培养的乳腺癌细胞多药耐药(MDR)的逆转作用。方法:以对药物敏感的人乳腺癌细胞系MCF-7和经阿霉素(ADM)诱导具有MDR表型的人乳腺癌耐药细胞系MCF-7/ADR为体外试验模型,分别单用及联用α-干扰素与维拉帕米对细胞系进行处理,MTT法检测各组细胞存活率,计算半数抑制浓度(IC50)、耐药倍数和逆转倍数;流式细胞术定量检测细胞表面P-170的表达。结果:α-干扰素与维拉帕米联用后使乳腺癌细胞耐ADM的IC50降低为0.32μmol·L-1,优于二者单用(2.29、1.23μmol·L-1),逆转倍数升高到51.88(二者单用为7.25、13.49),P-170表达低于二者单用。结论:单独应用α-干扰素、维拉帕米均可达到部分逆转MCF-7/ADR对ADM的耐药作用,但二者联用效果更强。     

叶酸受体及二氢叶酸还原酶与人乳腺癌细胞MCF-7/ADR多药耐药的关系

目的以人乳腺癌多药耐药细胞系MCF-7/ADR及其敏感亲本系MCF-7为对象,探讨叶酸受体(FOLRα)及其下游基因二氢叶酸还原酶(DHFR)的表达与乳腺癌细胞多药耐药的关系。方法 MTT法测定阿霉素的细胞毒性作用及DHFR抑制剂对MCF-7/ADR细胞多药耐药的逆转作用;RT-PCR检测细胞FOLRα和DHFR mRNA的表达水平;免疫细胞化学检测FOLRα、P-gp的表达水平。结果 MCF-7细胞增殖速度快于MCF-7/ADR细胞,MCF-7细胞FOLRα mRNA转录水平较MCF-7/ADR细胞高,而MCF-7/ADR细胞DHFR mRNA较MCF-7细胞转录水平高;免疫细胞化学显示MCF-7细胞FOLRα的表达高于MCF-7/ADR细胞,而MCF-7/ADR细胞P-gp的表达较MCF-7细胞高;MCF-7/ADR对甲氨蝶啶无耐药性,甲氨蝶啶对MCF-7/ADR细胞多药耐药有逆转作用。结论 MCF-7/ADR细胞FOLRα的表达水平下调可能与细胞增殖水平有关,其下游基因DHFR表达水平与MCF-7/ADR细胞的MDR可能存在相关性。     

补骨脂素逆转GST-π介导的多药耐药的研究

目的　探讨补骨脂素在逆转谷胱甘肽s-转移酶π（GST-π）介导的多药耐药中的作用,以及在MCF-7/ADR细胞中的可能机制。方法　研究时间：2015年至2020年。采用CCK-8法检测细胞活力,评价补骨脂素的细胞毒性和多药耐药逆转活性。采用实时聚合酶链反应（RT-PCR）检测GST-π的表达,检测靶基因的变化。采用免疫印迹法检测GST-π蛋白水平。采用免疫荧光法观察核因子κB（NF-κB）的活化情况。组间比较采用独立样本t检验,P<0.05为差异有统计学意义。结果　应用补骨脂素处理后,细胞内阿霉素药物浓度明显升高。与对照组相比,补骨脂素降低了治疗组GST-π在基因和蛋白水平上的表达。NF-κB抑制剂（SN50）可显著抑制乳腺癌MCF-7/ADR细胞中GST-π的表达。结论　NF-κB信号通路可能是GST-π介导的多药耐药发病机制之一。补骨脂素参与了逆转GST-π介导的多药耐药。GST-π介导的耐药机制可能与NF-κB信号通路有关,是NF-κB信号通路下游的关键因子。     

Glutathione S-transferases in wild-type and doxorubicin-resistant MCF-7 human breast cancer cell lines

1. Overexpression of glutathione S-transferases (GST) in breast cancer cells is hypothesized to be a component of the multifactorial doxorubicin-resistant phenotype. 2. We have characterized the expression of GST enzymes at the catalytic activity, protein and mRNA levels in wild-type MCF-7 (MCF-7/WT) human breast cancer cells and a line selected for resistance to doxorubicin (MCF-7/ADR), with the goal of modulating GST activity to overcome resistance. 3. The MCF-7/ADR cells were 30-65-fold more resistant to doxorubicin than the MCF-7/WT cells. 4. Total cytosolic GST catalytic activity was elevated 23-fold in the MCF-7/ADR cells as compared with the MCF-7/WT cells, and the MCF-7/ADR cells also showed 3-fold increases in catalytic activity toward GST mu and alpha class-selective substrates. Neither cell line showed detectable catalytic activity with a GST mu class-selective substrate. 5. MCF-7/ADR cells showed pronounced overexpression of GST mu protein and GST P1 mRNA in comparison with the wild-type cell line. Neither cell line displayed detectable GST alpha or mu at the protein level. 6. A glutathione analogue that functions as a selective GST alpha inhibitor was more potent at inhibiting total cytosolic GST catalytic activity in the MCF-7/ADR cell line than GST alpha and mu class-selective inhibitory glutathione analogues and the non-selective GST inhibitor ethacrynic acid. 7. The multidrug resistance-associated protein, which can function as a glutathione-conjugate transporter, appeared weakly overexpressed in the MCF-7/ADR cells in comparison with the MCF-7/WT cells.     

甲基莲心碱对耐阿霉素人乳腺癌细胞凋亡抗性的影响

目的　探讨甲基莲心碱 (neferine ,Nef)对耐阿霉素人乳腺癌细胞 (MCF 7/Adr)凋亡抗性的影响及其机制。方法　应用Tunel法和PI染色流式细胞仪检测细胞凋亡 ,间接免疫荧光流式细胞仪检测P gp的表达 ,高效液相色谱法(HPLC)检测细胞内阿霉素 (ADR)的浓度。结果　①MCF 7/Adr细胞能耐受 5mg·L- 1 ADR诱导的凋亡 ,而 1 ,5 ,1 0μmol·L- 1 Nef可使 5mg·L- 1 ADR诱导的MCF 7/Adr细胞凋亡从 7 95 %分别增加至 2 1 3 % ,2 7 9% ,61 3 % ;② 1 0μmol·L- 1 Nef可使MCF 7/Adr细胞内ADR积累由 0 52 μg·(1 0 6 cells) - 1 增加到 1 50 μg·(1 0 6 cells) - 1 ;③ 1 0 μmol·L- 1Nef作用 2 4h后 ,MCF 7/Adr细胞P gp的表达明显下降。结论　甲基莲心碱能逆转MCF 7/Adr细胞的凋亡抗性 ,其作用机制可能与抑制P gp的功能和表达、增加ADR在MCF 7/Adr细胞内的积累有关     

Long noncoding RNA SNHG7-miRNA-mRNA axes crosstalk with oncogenic signaling pathways in human cancers

LncRNAs and miRNAs are the two most important non-coding RNAs, which have been identified to be associated with cancer progression or prevention. The dysregulation of lncRNAs conducts tumorigenesis and metastasis in different ways. One of the mechanisms is that lncRNAs interact with miRNAs to regulate distinct cellular and genomic processes and cancer progression. LncRNA SNHG7 as an oncogene sponges miRNAs and develops lncRNA-miRNA-mRNA axes, leading to the regulation of several signaling pathways such as Wnt/β-Catenin, PI3K/AKT/mTOR, SIRT1, and Snail-EMT. Therefore, in this article, after a brief overview of lncRNA SNHG7-miRNA-mRNA axes' contribution to cancer development, we will discuss the role of lncRNA SNHG7 in the genes expression and signaling pathways related to cancers development via acting as a ceRNA.     

Annosquacin B induces mitochondrial apoptosis in multidrug resistant human breast cancer cell line MCF-7/ADR through selectively modulating MAPKs pathways

Context: Multidrug resistance (MDR) is a major obstacle to efficient therapy of cancers. It is a prime concern for researchers to find compounds with anti-proliferative activity on MDR cell lines. In recent years, annonaceous acetogenins (ACGs) were reported to have anti-proliferative activity. However, the underlying mechanisms are still unknown.

Objective: This study determines the mechanisms of anti-proliferative activity induced by Annosquacin B (AB) against MCF-7/ADR cells.

Material and methods: The cytotoxicity of AB at varying concentrations (0.64, 1.6, 4, 10, 25, 62.5, 156.25?μM) on MCF-7/ADR cells was assessed using the MTT assay. Annexin V-FITC/propidium iodide staining and Acrinidine orange and ethidium bromide (AO/EB) staining were employed to investigate whether AB (14, 7, 3.5?μM) could induce apoptosis in MCF-7/ADR cells. Levels of caspase-3 and caspase-9, Bax, Bcl-2 and MAPKs kinases were evaluated by western blot assay following treatment with various concentrations of AB (3.5, 7, 14?μM) at different time points (0, 0.5, 1, 2, 4, 8, 12?h).

Results and conclusion: MTT assay showed that AB significantly decreased cell viability on MCF-7/ADR (IC₅₀ of 14.69?μM). AB-induced apoptosis in MCF-7/ADR cells through mitochondrial apoptosis pathways. It induced typical apoptosis by morphologic changes; elevate levels of caspase-3, caspase-9 as well as the ratio of Bax/Bcl-2. In addition, AB increased the expression of p-p38 MAPK and decreased the expression of p-JNK, while whether ERK1/2 had an effect on the MCF-7/ADR apoptosis remains to be determined.     

三氧化二砷对胃癌细胞SGC7901/ADR GST-π和TopoⅡ表达的影响

目的探讨三氧化二砷(As2O3)对胃癌细胞SGC7901/ADR阿霉素(ADM)耐药性的逆转作用和对GSTπ和TopoⅡ表达的影响。方法用MTT法检测As2O3的非细胞毒性浓度和SGC7901/ADR细胞对ADM的敏感性,用流式细胞仪检测细胞内药物浓度及用免疫组织化学法检测细胞GSTπ和TopoⅡ的表达。结果与结论0.4~0.8μmol.L-1As2O3对耐药细胞SGC7901/ADR无明显毒性(P<0.01),As2O3可下调GSTπ表达,提高SGC7901/ADR细胞内ADM浓度,部分逆转SGC7901/ADR细胞对ADM的耐药性。