bcl-2反义寡核苷酸增强5-Fu诱导乳腺癌细胞凋亡的研究

目的　观察转染bcl -2反义寡核苷酸 (ASODN )能否增强 5 -氟脲嘧腚 ( 5 -Fu)诱导乳腺癌细胞株MCF -7凋亡。方法　通过电穿孔转染bcl -2ASODN和对照序列 ,荧光显微镜定量检测转染以后MCF -7凋亡率的变化。结果　和对照序列相比 ,转染bcl -2ASODN显著增高 5 -Fu诱导MCF -7的细胞凋亡率 (P <0 .0 1)。结论　联用bcl -2ASODN和 5 -Fu可能改善乳腺癌的治疗效果。     

神经酰胺诱导人乳腺癌细胞凋亡的研究

目的 :观察神经酰胺对人乳腺癌细胞株MCF 7及耐多柔比星细胞株MCF 7/ADR的诱导凋亡作用及其对bcl 2基因表达的影响 ,探讨神经酰胺诱导凋亡的机制。方法 :采用MTT法检测细胞生存率 ,用流式细胞术检测凋亡率 ,运用流式细胞术、RT PCR方法检测bcl 2基因表达。结果 :神经酰胺对MCF 7、MCF 7/ADR细胞有明显的抑制生长作用。 2 5 μmol/LC6 神经酰胺作用48h后 ,MCF 7及MCF 7/ADR细胞凋亡率分别为( 2 0 70± 2 66) %、( 12 3 9± 1 76) % ,前者凋亡率高于后者 ,P <0 0 1。流式细胞术检测 ,MCF 7、MCF 7/ADR细胞bcl 2蛋白阳性率分别为 ( 2 7 5 9± 2 94) %、( 79 5 6±3 2 0 ) %。MCF 7/ADR细胞经神经酰胺作用后 ,bcl 2蛋白及mRNA水平均降低。结论 :神经酰胺对MCF 7、MCF 7/ADR细胞有抑制生长及诱导凋亡作用 ,神经酰胺诱导凋亡可能是通过下调bcl 2基因表达而实现的     

β-榄香烯逆转人乳腺癌MCF-7/ADM细胞对阿霉素耐药性的研究

目的　探讨 β 榄香烯 (β ELE)逆转人乳腺癌MCF 7/ADM细胞对阿霉素 (ADM)的耐药性。方法　采用MTT法测定β ELE对人乳腺癌MCF 7/ADM细胞药物敏感性的影响。经荧光分光光度法检测 β ELE对细胞内化疗药物ADM积累的影响 ,应用流式细胞术观察耐药细胞的凋亡抑制蛋白bcl 2改变。结果　β ELE对MCF 7/ADM的耐药性有明显逆转作用 ,非细胞毒性剂量 (6 μg/ml)及低毒剂量 (13μg/ml)的 β ELE逆转倍数分别为 1.4倍及 2 .2倍。β 榄香烯作用后 ,MCF 7/ADM的细胞内ADM浓度明显增加 (P <0 .0 1) ,bcl 2由 90 .2 %降至 70 .0 % (P <0 .0 5 )。结论　β ELE可部分逆转MCF 7/ADM细胞的耐药性 ,逆转机制与增加细胞内药物积累及降低bcl 2的表达有关。     

人乳腺癌细胞凋亡与去磷酸化RB蛋白的关系

目的 :研究乳腺癌细胞凋亡与去磷酸化RB蛋白的关系。方法 :以乳腺癌细胞株MCF 7/S(化疗敏感细胞株 )和MCF 7/ADR(耐多柔比星细胞株 )为研究对象 ,用MTT比色法检测乳腺癌细胞的化疗敏感性 ;采用免疫细胞化学法检测多柔比星 (ADR)作用前后RB蛋白的表达状态 ;应用流式细胞术检测ADR诱导乳腺癌细胞凋亡程度。结果 :ADR能抑制敏感细胞MCF 7/S增殖 ,半数抑制浓度 (IC50 )为 0 .12 8μg/ml,而对应的耐药细胞MCF 7/ADRIC50值为 10 .89μg/ml,MCF 7/S细胞较MCF 7/ADR细胞对ADR敏感 86倍。加ADR前两种细胞胞核中的磷酸化RB蛋白均为阳性 ,去磷酸化RB蛋白均为阴性。经不同浓度ADR处理后 ,随着ADR浓度的增加 ,MCF 7/S细胞去磷酸化RB蛋白表达量逐渐增高 ,而MCF 7/ADR细胞去磷酸化RB蛋白表达量无明显增高。流式细胞术检测细胞凋亡和细胞周期 ,结果表明ADR诱导MCF 7/S细胞凋亡作用比MCF 7/ADR强 (P <0 .0 1)。结论 :乳腺癌MCF 7/S细胞凋亡与去磷酸化RB蛋白表达呈正相关 (P <0 .0 5 ) ,而MCF 7/ADR细胞凋亡与去磷酸化RB无明显相关 (P >0 .0 5 )。     

甘草酸对人乳腺癌细胞增殖抑制和诱导凋亡作用的研究

目的　探讨甘草酸对人乳腺癌细胞 (MCF 7)增殖抑制和诱导凋亡的作用 ,并探讨凋亡发生与细胞内Ca2 浓度( [Ca2 ]i)变化的关系。方法　 2 .5～ 12 .5mmol/L甘草酸处理MCF 7细胞 2 4h ,采用MTT比色法测定细胞增殖能力。 5 .0mmol/L、7.5mmol/L和 10 .0mmol/L甘草酸处理MCF 7细胞 2 4h ,用末端脱氧核苷转移酶介导dUTP末端标记法和AnnexinV流式细胞仪法检测凋亡细胞。 7.5mmol/L甘草酸处理MCF 7细胞 2 4h ,采用Fura 2荧光负载方法测定 [Ca2 ]i的变化。结果　甘草酸从 5 .0mmol/L浓度起对MCF 7细胞的增殖抑制率显著升高 (P <0 .0 1) ,呈剂量依赖性 ;半增殖抑制浓度 (IC50 )为 15 .8mmol/L。 7.5mmol/L和 10 .0mmol/L甘草酸使细胞凋亡率显著升高 (P <0 .0 5和P <0 .0 1)。甘草酸处理组的 [Ca2 ]i明显低于对照组 (P <0 .0 5 )。结论　甘草酸具有抑制MCF 7细胞增殖和诱导凋亡的作用 ;其诱导细胞凋亡可能与细胞内Ca2 水平下调有关     

三苯氧胺对乳腺癌细胞凋亡和耐药性的影响

目的　观察雌激素 (E2 )及三苯氧胺 (tamoxifen ,TAM)对乳腺癌MCF 7细胞凋亡调控基因 (bax、bcl 2 )及多药耐药基因 (mdr 1)的影响。方法　利用免疫组化法及原位杂交法检测MCF 7细胞在E2 和TAM作用后bax、bcl 2及mdr 1基因的变化。结果　E2 可以明显刺激bcl 2和mdr 1基因表达 ,而TAM则可使其降低。首次利用人工合成的bax寡聚脱氧核苷酸探针 ,对肿瘤细胞内baxmRNA进行原位杂交 ,显示baxmRNA可被E2 下调 ,但在TAM作用下明显升高。相关性分析显示 ,bcl 2和mdr 1基因之间在TAM作用后有相关性 (r=0 6 ,P <0 0 5 )。结论　TAM在乳癌内分泌治疗中不仅可调节肿瘤细胞凋亡 ,也可降低肿瘤细胞耐药性 ,抗凋亡基因bcl 2和多药耐药性之间有密切的功能联系 ,对其深入研究将有助于肿瘤内分泌治疗的进展。     

LINC00536负调控Notch信号通路对乳腺癌细胞增殖、迁移和侵袭的影响

目的 探讨长基因间非蛋白质编码RNA 536(LINC00536)在乳腺癌细胞增殖、迁移和侵袭中的生物学作用。方法 采用实时荧光定量PCR(q PCR)检测人正常乳腺上皮细胞MCF-10A和乳腺癌细胞MCF7的LINC00536水平,向MCF7细胞转染LINC00536干扰序列si-LINC00536或阴性对照序列si-NC后采用q PCR和Western blotting检测Notch1和Hes1的水平。将MCF7细胞分为未转染的对照组、转染si-NC的阴性对照(si-NC)组、干扰LINC00536的si-LINC00536组和LINC00536干扰+Notch激动剂丙戊酸(si-LINC00536+VPA)组。MTT法、伤口愈合实验和Transwell小室实验分别评估细胞增殖、迁移和侵袭能力。结果 MCF7细胞的LINC00536水平高于MCF7细胞(P<0.05)。与未转染和转染si-NC的细胞相比,MCF7细胞转染si-LINC00536后的LINC00536、Notch1和Hes1水平降低(P<0.05)。si-LINC00536组MCF7细胞的增殖活力、划痕愈...     

基因促进TRAIL诱导乳腺癌MCF 7细胞的凋亡

目的:研究抑制促分裂原活化蛋白激酶/细胞外信号调节激酶激酶3(mitogenactivated protein/extracellular signal regulated kinasekinase 3,MEKK 3)基因表达促进TRAIL诱导乳腺癌MCF7细胞凋亡的作用，寻找乳腺癌临床治疗新策略。方法：应用MTT法检测人TRAIL对MCF7细胞生长的抑制作用。合成MEKK3siRNA，应用脂质体介导MEKK3siRNA转染入人乳腺癌细胞MCF7，以RTPCR和Western blotting法检测MCF7细胞MEKK 3 mRNA和蛋白的表达。应用MTT法和流式细胞术检测MEKK3siRNA与TRAIL联合处理后MCF7细胞的增殖和凋亡。结果：TRAIL具有抑制MCF7细胞增殖作用，但其抑制作用较弱。MEKK3siRNA转染后能有效而稳定地抑制MCF7细胞中 MEKK3 mRNA和蛋白的表达(P<0.01)。TRAIL与MEKK3siRNA联合处理MCF7细胞较TRAIL单独处理更明显地抑制细胞增殖活力(P<0.05)，更明显地增加细胞凋亡率(P<001)。结论：siRNA沉默 MEKK3基因能显著促进TRAIL对乳腺癌MCF7细胞凋亡的诱导作用，为探讨乳腺癌治疗新方案提供了实验依据。     

转染bcl-2反义寡核苷酸增强5-FU诱导胃癌细胞株SGC-7901凋亡

目的　探讨转染bcl 2反义寡核苷酸 (ASODN)能否增强 5 氟脲嘧腚 (5 -FU)诱导胃癌细胞株SGC790 1的细胞凋亡。方法　通过脂质体转染bcl 2ASODN和对照序列 ,凋亡率由流式细胞仪检测。酶联免疫法 (ELISA)用于检测细胞内源性bcl 2蛋白的表达 ,以证实反义序列的特异性。结果　和对照ODN相比 ,转染bcl 2ASODN显著增强 5 FU诱导的细胞凋亡率 (P<0 .0 1)。ELISA法显示SGC790 1的内源性bcl 2蛋白表达下降 (P <0 .0 1)。结论　bcl 2ASODN能增强 5 FU诱导胃癌细胞的凋亡率 ,这将为胃癌治疗提供有用的实验室依据。     

榄香烯乳区域动脉灌注对乳腺癌细胞凋亡和增殖的影响

目的：观察中药提取物榄香烯乳术前区域动脉灌注对乳腺癌细胞凋亡和增殖的影响。方法：应用末端转移酶介导的脱氧核苷酸末端标记法（TUNEL法）和增殖细胞核抗原（PCNA）、凋亡抑制基因蛋白（bcl－2）免疫组化检测方法,观察术前榄香烯乳治疗组14例和Ⅰ期手术组17例乳腺癌标本的凋亡指数,增殖指数和bcl－2蛋白表达强度的差异。结果：榄香烯乳治疗组凋亡指数（7．97±1．50）明显高于Ⅰ期手术对照组（2．26±0．49）;bcl－2蛋白表达（分值0．50±0．67）明显低于对照组（1．38±0．87）,P值均＜0．01;榄香烯乳治疗组增殖细胞核抗原指数（44．54±9．99）与对照组（42．80±6．78）差异无显著性,P＞0．05;14例术前榄香烯乳治疗组等级相关分析凋亡指数与bcl－2分值呈中度负相关（rs＝－0．508）。结论：乳腺癌患者术前区域动脉灌注榄香烯乳可降低乳腺癌细胞bcl－2基因蛋白的表达,诱导乳腺癌细胞凋亡。     

甲异靛对人乳腺癌MCF-7细胞增殖和凋亡影响的实验研究

目的:研究甲异靛对人乳腺癌MCF-7细胞增殖抑制和诱导凋亡作用。方法:采用MTT法检测甲异靛对MCF-7乳腺癌细胞的增殖抑制;流式细胞仪测定细胞凋亡率;光学显微镜观察细胞形态的变化;westernblot法测定caspase-3、PARP及bcl-2表达。结果:甲异靛能明显抑制MCF-7乳腺癌细胞增殖。甲异靛诱导MCF-7细胞凋亡,呈现典型细胞凋亡的形态变化,并呈时间和剂量依赖性,凋亡率最高可达(68.40±4.87)%,在细胞凋亡过程中出现PARP分子断裂和bcl-2下调,未检测到caspase-3。结论:甲异靛能诱导MCF-7乳腺癌细胞凋亡抑制细胞增殖,其发生机制可能与下调bcl-2有关。     

甲异靛对人乳腺癌MCF-7细胞增殖和凋亡影响的实验研究

目的：研究甲异靛对人乳腺癌MCF-7细胞增殖抑制和诱导凋亡作用。方法：采用MTT法检测甲异靛对MCF-7乳腺癌细胞的增殖抑制;流式细胞仪测定细胞凋亡率;光学显微镜观察细胞形态的变化;westernblot法测定caspase-3、PARP及bcl-2表达。结果：甲异靛能明显抑制MCF-7乳腺癌细胞增殖。甲异靛诱导MCF-7细胞凋亡,呈现典型细胞凋亡的形态变化,并呈时间和剂量依赖性,凋亡率最高可达（68.40±4.87）%,在细胞凋亡过程中出现PARP分子断裂和bcl-2下调,未检测到caspase-3。结论：甲异靛能诱导MCF-7乳腺癌细胞凋亡抑制细胞增殖,其发生机制可能与下调bcl-2有关。     

Bcl-2/bcl-xL bispecific antisense treatment sensitizes breast carcinoma cells to doxorubicin,paclitaxel and cyclophosphamide

Overexpression of the anti-apoptotic proteins bcl-2 and bcl-xL is implicated in breast cancer development, tumor progression and drug resistance. Here we describe the use of the bcl-2/bcl-xL bispecific antisense oligonucleotide 4625 to sensitize breast carcinoma cells to anti-cancer drugs routinely used in breast cancer therapy. MCF7 cells were treated with oligonucleotide 4625, doxorubicin, paclitaxel or cyclophosphamide alone, or with combinations of oligonucleotide and the anti-cancer drugs. As measured in cell viability assays, treatment with the various combinations reduced the number of viable MCF7 cells more effectively than treatment with the single drugs alone. Treatment with a sequence control oligonucleotide did not affect cell viability. All combination treatments induced apoptosis as demonstrated by the appearance of massive nuclear condensation in a high proportion of the cells. To further characterize the interaction between 4625 and doxorubicin, paclitaxel or cyclophosphamide, the median-effect method was used. In MCF7 cells all combinations resulted in potent synergistic effects over a broad range of toxicity with combination indices ranging from 0.8 to 0.1. Similarly, strong synergistic interactions between oligonucleotide 4625 and the anti-cancer drugs were also observed in cultures of the breast carcinoma cell line MDA-MB-231. Our data suggest the use of 4625 as a potent adjuvant in breast cancer chemotherapy.     

C-erbB-2反义寡核苷酸抑制乳腺癌细胞增殖

目的观察反义寡核苷酸(antisense oligodeoxynucleotide,ASODN)能否降低人乳腺癌细胞株MCF-7、c-erbB-2基因的表达,以及能否抑制其细胞增殖.方法将c-erbB-2 ASODN及其对照序列(空白对照和错配序列)通过脂质体转染MCF-7细胞,应用Western blot观察c-erbB-2蛋白表达的变化,然后应用MTT观察细胞增殖.结果c-erbB-2 ASODN能特异性下调MCF-7细胞c-erbB-2蛋白,而且能抑制其细胞增殖.结论实验结果认为应用c-erbB-2 ASODN抑制乳腺癌细胞增殖具有可行性.     

Combined targeted inhibition of bcl-2, bcl-XL, epidermal growth factor receptor, and protein kinase A type I causes potent antitumor, apoptotic, and antiangiogenic activity.

PURPOSE: This study investigated whether the functional and structural interactions between epidermal growth factor receptor (EGFR), protein kinase AI (PKAI), and bcl-2/bcl-xL could be exploited to obtain cooperative antitumor effects against models of human colon and breast cancer. EXPERIMENTAL DESIGN: Antisense bcl-2/bcl-xL (4625), antisense PKAI (AS-PKAI), and ZD1839 ("Iressa"), a selective EGFR tyrosine kinase inhibitor, were administered as single agents and in combination against GEO colon and ZR-75-1 breast cancer cell lines in vitro and to mice bearing s.c. GEO human tumor xenografts in vivo. Effects on growth inhibition, vascular endothelial growth factor secretion, and induction of apoptosis were assessed. RESULTS: Antisense bcl-2/bcl-xL inhibited the growth of GEO and ZR-75-1 cells in vitro, reducing bcl-2 and bcl-xL expression and vascular endothelial growth factor secretion. Supra-additive growth inhibition and apoptosis induction were observed when 4625 was combined with ZD1839 or AS-PKAI. Combining all three agents resulted in a complete growth inhibitory effect in vitro. Antisense bcl-2/bcl-xL, AS-PKAI, and ZD1839 administered in vivo as single agents caused growth inhibition of GEO xenografts. Combining all three agents caused a marked and sustained effect, with 50% growth inhibition and 50% of mice tumor free 5 weeks after treatment withdrawal. The combination was well tolerated. CONCLUSIONS: The combination of 4625, AS-PKAI, and ZD1839 resulted in a strong antiproliferative, proapoptotic, and antiangiogenic response, suggestive of a functional interaction between EGFR, PKAI, and bcl-2/bcl-xL and providing a rationale for the selection of specific molecular treatments for the development of therapeutic strategies. Iressa is a trademark of the AstraZeneca group of companies.     

Effects of regulatory domains of specific isoforms of protein kinase C on growth control and apoptosis in MCF-7 breast cancer cells

Protein kinase C (PKC) is a multigene family consisting of at least 11 isoforms that play key roles in growth control and tumorigenesis. To understand the roles of specific isoforms of PKC in breast cancer, we generated derivatives of the human breast cancer cell line MCF-7 that stably overexpress dominant negative mutants (REG) of PKC-alpha, -epsilon, or -zeta, which encode only the regulatory domains of the respective isoforms. When stimulated to re-enter the cell cycle after serum starvation, the MCF-7/PKC-alpha-REG cell line exhibited enhanced cell-cycle progression in comparison to the control cell line. These cells also showed increased sensitivity to growth inhibition and induction of apoptosis in response to various cytotoxic stimuli, including serum starvation, tamoxifen, and gamma-radiation. Western blot analysis indicated that the MCF-7/PKC-alpha-REG cell line displayed marked decreases in the levels of the cyclin-dependent kinase inhibitor p21CIP1 and the anti-apoptotic protein bcl-2. Similar, but less striking, effects were seen in the MCF-7/PKC-epsilon-REG cell line, and the MCF-7/PKC-zeta-REG cell line showed minimal changes, when compared to the control cells. Taken together, these results suggest that the endogenous PKC-alpha in MCF-7 cells plays a critical role in regulating cell-cycle control and apoptosis, in part through upregulating the expression of p21CIP1 and bcl-2. Therefore, inhibitors of PKC-alpha may potentiate the activity of cytotoxic agents in the therapy of breast cancer.     

Differential sensitivity of MCF-7 and LCC2 cells, to multiple growth inhibitory agents: possible relation to high bcl-2/bax ratio?

Comparison of LCC2, the E(2)-independent, tamoxifen-resistant subline of the MCF-7 human breast cancer cell line with its parent line, disclosed that it is more resistant to growth inhibition and apoptosis induction by a variety of agents acting by diverse mechanisms. Thus, LCC2 cells can serve as a useful in-vitro model for the study of the molecular mechanisms of this resistance. It was found that bcl-2 protein and mRNA were elevated and that bax protein and mRNA were reduced in LCC2 compared with MCF-7 cells. Incubation of both lines in the presence of bcl-2 antisense caused growth inhibition and reduced bcl-2 protein levels only in MCF-7 cells, suggesting the involvement of bcl-2 in the regulation of normal growth of breast cancer cells. Increased bcl-2 expression in breast cancer cells may correlate with their resistance to growth inhibitory agents. Bcl-2 is a useful target for enhancing the effects of growth inhibitory agents.     

Low doses of alpha particle irradiation modify the expression of genes regulating apoptosis in human MCF-7 breast cancer cells

The possibility of modifying apoptosis-related genes in tumor cells is an interesting line of research that calls for multidisciplinary experimentation to describe its characteristics and the conditions required. In vitro low doses of alpha particle irradiation due to radon have an antiproliferative effect on the growth of MCF-7 cells and increase the sensibility of cancer cells to taxol, a chemotherapeutic agent that induces cellular apoptosis. The present study examines the in vitro effects of low doses of alpha particle irradiation from the gas radon on the expression of some bcl-2 family apoptosis-related genes. The analyzed genes were bax, bcl-2 and bcl-x, with known responses to genotoxic stress (bcl-2) or ionising radiation (bax and bcl-x) in MCF-7 human breast cancer cells. The results obtained indicate that the cell line studied expresses the mentioned genes and they demonstrate that irradiation with low radon doses of MCF-7 cells induces underexpression of both bax and bcl-2 genes. Interestingly, the mRNA levels of the full-length bcl-x gene (bcl-xL) were overexpressed after irradiation, and we found significant mRNA levels of an alternative mRNA splicing form of the same gene (bcl-xS), which enhances the apoptotic sensitivity of the cell. The increased sensitivity to apoptosis resulting from bcl-xS overexpression is important because it might improve the efficacy of chemotherapeutic agents used to treat cancers which act through induction of apoptosis. The finding that low radiation doses of alpha particles from the gas radon modulate the expression of apoptosis-related genes suggests a therapeutic utility for this naturally occurring agent.     

乳腺癌耐药细胞中c-fos抗凋亡作用的研究

背景与目的：乳腺癌是女性最常见的恶性肿瘤之一,且患者死亡率居高不下,其中乳腺癌耐药是导致临床化疗失败的主要原因。该课题组采用已建立的乳腺癌耐药细胞模型MCF-7/ADR及其敏感株MCF-7,旨在探讨c-fos在乳腺癌耐药细胞中的详细作用机制。方法：MTT检测上述细胞对多柔比星的敏感性,并通过实时定量PCR(real-time PCR,RT-PCR)检测上述细胞中mdr-1及c-fos的mRNA表达情况;3 μmol多柔比星分别处理MCF-7细胞12、24、36 h后采用RT-PCR检测细胞中c-fos mRNA的表达,以监测化疗药物处理过程中乳腺癌细胞c-fos的表达变化过程;构建相应载体得到了c-fos稳定干扰细胞株及其对照细胞株：MCF-7/ADR/si-fos-8B、MCF-7/ADR/si-fos-3D和MCF-7/ADR/siNC,采用MTT检测干扰c-fos后对5-FU及顺铂的敏感性变化;流式细胞术检测上述药物及γ射线照射处理后细胞凋亡的情况;罗丹明123检测乳腺癌耐药细胞的外排能力;RT-PCR及蛋白质印迹法(Western blot)分别检测c-fos干扰后,凋亡相关基因bax、bcl-2、puma、p53及mdr-1等的表达。结果：与敏感细胞MCF-7相比,MCF-7/ADR细胞中c-fos及mdr-1的表达显著升高,且对多柔比星的耐药倍数为敏感株的近40倍;在3 μmol多柔比星处理MCF-7之后c-fos的表达逐渐升高,结果显示,c-fos在乳腺癌的耐药表型形成早期即开始发挥作用;干扰c-fos后,细胞对药物(5-FU、顺铂)的敏感性增高,且经药物处理及γ射线照射后稳定干扰细胞株的凋亡率显著升高,说明干扰c-fos后乳腺癌耐药细胞在受到外界刺激后,更易于发生凋亡;RT-PCR及Western blot检测结果显示,干扰c-fos后,bax、puma、p53的表达明显升高,而bcl-2及mdr-1的表达显著降低。结论：在乳腺癌耐药细胞MCF-7/ADR中发现,c-fos呈异常高表达,其可能通过调节乳腺癌细胞凋亡信号通路蛋白的变化抑制乳腺癌细胞的凋亡,促进了乳腺癌耐药表型的形成。由此,c-fos可作为克服乳腺癌耐药治疗的一个潜在靶点用于今后的药物开发。     

紫杉醇脂质体对乳腺癌MCF-7细胞生长抑制作用的机制

目的 分析紫杉醇脂质体对乳腺癌MCF-7细胞的生长抑制作用,观察药物作用的时间浓度关系并探究其作用机制.方法 应用不同剂量紫杉醇脂质体对MCF-7细胞进行处理,通过MTT法检测细胞存活率,倒置显微镜观察细胞形态,流式细胞分析技术检测细胞凋亡情况及其对细胞周期的影响,Western blot法检测bcl-2蛋白表达情况.结果 紫杉醇脂质体对MCF-7细胞有明显的剂量时间依赖效应.紫杉醇与紫杉醇脂质体均可将MCF-7细胞阻滞在G2/M期,且随药物浓度增加,凋亡细胞所占比例逐渐增加.通过Western blot法检测发现,紫杉醇脂质体作用后MCF-7细胞bcl-2蛋白表达明显下降,bax蛋白表达明显上调,bax/bcl-2比例明显上调.结论 与紫杉醇相比,紫杉醇以脂质体对人乳腺癌MCF 7细胞具有同样的抑制作用,其促凋亡机制之一为调控bcl-2及bax蛋白表达.