雷公藤内酯醇通过调控miR-142-3p/HSP70通路抑制人乳腺癌MCF-7细胞增殖、侵袭和迁移

目的:探究雷公藤内酯醇(TP)通过miR-142-3p/HSP70信号通路对人乳腺癌MCF-7细胞恶性生物学行为的影响。方法:常规培养MCF-7细胞,将其分为6组:对照组、TP组、miR-142-3p inhibitor组、TP+inhibitor组、miR-142-3p mimic组和TP+mimic组,用转染试剂将相应的核酸或质粒转染MCF-7细胞。qPCR法、EdU细胞增殖实验、Transwell小室实验、细胞划痕实验、WB法分别检测转染后各组MCF-7细胞中miR-142-3p和HSP70 mRNA的表达,MCF-7细胞的增殖、侵袭、迁移能力和HSP70蛋白表达水平。结果:TP或miR-142-3p过表达能显著促进MCF-7细胞中miR-142-3p和HSP70的表达,敲减miR-142-3p则可明显抑制MCF-7细胞中miR-142-3p和HSP70的表达,TP可逆转由敲减miR-142-3p对MCF-7细胞中miR-142-3p和HSP70表达的影响;TP、过表达miR-142-3p均可明显抑制MCF-7细胞的增殖、迁移和侵袭能力(均P<0.05),敲减miR-142-3p则均可促进MCF-7细胞的增殖、迁移和侵袭能力(均P<0.05),TP可逆转由敲减miR-142-3p对MCF-7细胞恶性生物学行为的影响(均P<0.05)。结论:TP可通过调控miR-142-3p/HSP70信号通路,进而抑制MCF-7细胞的增殖、侵袭和迁移能力。

TNF-ɑ调控LRG1促进乳腺癌MCF-7细胞增殖、侵袭和迁移

目的:研究TNF-α对乳腺癌MCF-7细胞中LRG1蛋白表达的调控及其对乳腺癌MCF-7细胞增殖、侵袭和迁移能力的影响及相关分子机制。方法:MTT实验检测不同浓度TNF-α处理后MCF-7细胞活力;EdU实验、Transwell实验和划痕实验分别检测抑制LRG1表达后细胞增殖、侵袭以及迁移能力;Western blot检测细胞内MAPK信号通路中p-p38蛋白表达。结果:低浓度TNF-α处理乳腺癌MCF-7细胞,细胞活力增强;抑制LRG1表达后细胞增殖能力下降,侵袭细胞数、细胞迁移率以及p-p38蛋白表达均下降。结论:TNF-ɑ通过调控LRG1的表达促进乳腺癌MCF-7细胞增殖、侵袭和迁移,这一过程可能通过激活p38MAPK信号通路来实现。

毛酸浆内酯通过抑制STAT3诱导人乳腺癌MCF-7细胞凋亡

[目的]旨在探讨信号转导和转录激活因子3(STAT3)在毛酸浆内酯(PPB)诱导人乳腺癌MCF-7细胞凋亡中发挥的作用。[方法]采用荧光染色法分析PPB诱导MCF-7细胞凋亡;使用生物信息学方法预测PPB抗乳腺癌的潜在机制;采用噻唑蓝(MTT)法考察STAT3抑制剂S3I-201以及STAT3小干扰RNA(siRNA)对PPB抑制MCF-7细胞生长的作用;采用蛋白免疫印迹(Western Blot)法考察PPB单独处理或STAT3 siRNA预处理后对MCF-7细胞中STAT3、B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、半胱氨酸天冬氨酸蛋白酶8(Caspase8)、半胱氨酸天冬氨酸蛋白酶9(Caspase9)、细胞色素c(Cytochrome c)以及多聚ADP核糖聚合酶(PARP)蛋白表达的影响。[结果]MCF-7细胞经PPB作用后凋亡形态特征明显,凋亡比例上升;生物信息学结果显示PPB与乳腺癌疾病的共同靶点STAT3在乳腺癌组织中高表达,单基因GSEA结果提示STAT3高表达与凋亡信号通路呈负相关;Western Blot法检测结果显示PPB能够抑制STAT3的磷酸化;S3I-201抑制剂或siRNA敲降STAT3均能进一步促进PPB抑制MCF-7细胞生长;此外,敲降STAT3进一步增加PPB对促凋亡蛋白Bax、Cytochrome c、裂解的Caspase8(Cleaved-Caspase8)、裂解的Caspase9(Cleaved-Caspase9)以及裂解的PARP(Cleaved-PARP)的促进作用,并增加PPB对抗凋亡蛋白Bcl-2的抑制作用。[结论]PPB通过抑制STAT3诱导人乳腺癌MCF-7细胞凋亡。

香豆酸诱导MCF-7细胞凋亡的代谢与氧化应激影响

目的 探讨香豆酸诱导乳腺癌细胞MCF-7凋亡的机制及氧化应激与代谢的影响。方法 采用氧化相关蛋白活性研究香豆酸对MCF-7氧化应激的影响;液相质谱仪结合代谢组学探索香豆酸对MCF-7细胞代谢的影响。结果 香豆酸呈浓度依赖式对MCF-7细胞凋亡具有一定的促进作用,并上调细胞的氧化应激性导致MCF-7细胞氧化系统失衡;同时香豆酸影响MCF-7的细胞代谢,主要是体现糖代谢,富集显著通路集糖酵解;并筛选到差异代谢物563个,其中上调463个,下调100个。结论 香豆酸诱导MCF-7细胞凋亡作用机制可能是通过影响细胞的氧化应激性以及调控细胞糖代谢来实现。

灵菌红素对耐阿霉素人乳腺癌细胞MCF-7/ADR的作用研究

目的探讨灵菌红素对耐阿霉素人乳腺癌细胞MCF-7/ADR的作用。方法采用平板发酵粘质沙雷氏菌WA12-1-18生产灵菌红素,CCK-8测定灵菌红素的体外活性及MCF-7/ADR的耐药指数。构建裸鼠皮下移植瘤模型,灵菌红素高、低剂量组分别腹腔注射5.0、2.5 mg/kg灵菌红素,生理盐水对照位腹腔注射等体积生理盐水,每4天1次,连续用药24 d,观察移植瘤的体积、质量及裸鼠体质量,HE染色观察移植瘤组织及裸鼠主要脏器的病理情况,免疫组织化学检测移植瘤Ki-67的表达。结果获得的灵菌红素质量分数为95.18%,对MCF-7和MCF-7/ADR的IC50分别为0.484μg/mL和0.264μg/mL。MCF-7/ADR耐药指数13,符合细胞耐药株的要求。灵菌红素处理组裸鼠移植瘤增长速度较生理盐水组慢,肿瘤细胞排列稀疏,核小且着色较浅,Ki-67染色后棕色明显减少。灵菌红素2.5 mg/kg组和灵菌红素5 mg/kg组,在荷MCF-7/ADR裸鼠中抑瘤率分别为37.23%和53.72%。另外,各组裸鼠体质量差异无统计学意义,主要脏器无明显病理变化。结论灵菌红素可抑制裸鼠体内耐阿霉素人乳腺癌细胞MCF-7/ADR的生长,对心、肝、脾、肺和肾等主要脏器无明显毒副作用,为灵菌红素在耐阿霉素乳腺癌的临床应用提供了实验依据。

羟基积雪草酸对乳腺癌MCF-7细胞增殖、凋亡和自噬的影响

目的探讨羟基积雪草酸(madecassic acid,MA)对乳腺癌MCF-7细胞增殖、凋亡及自噬的影响。方法将MCF-7细胞分为阴性对照组、不同浓度的MA(80、100、120、140、160μmol/L)组、不同浓度的他莫昔芬(10、20、30、40、50、35μmol/L)组,干预24、36、48 h。初步确定MA发挥抗乳腺癌作用的最佳浓度和最佳时间后,采用MTT法检测细胞活力,计算相应的半抑制浓度(half maximal inhibitory concentration,IC50)值;流式细胞术检测细胞凋亡;JC-1荧光探针检测线粒体膜电位变化;Western blot法检测细胞增殖蛋白细胞核抗原蛋白(proliferating cell nuclear antigen,PCNA)、自噬蛋白苄氯素-1(Beclin-1)、微管相关蛋白1轻链3-Ⅱ/Ⅰ(microtubule-associated protein1 light chain 3Ⅱ/Ι,LC3Ⅱ/Ι)、螯合体1(protein 62,p62)的蛋白相对表达水平。透射电镜检测自噬小体。结果发挥抗肿瘤作用的他莫昔芬最佳浓度为35μmol/L,MA最佳浓度为140μmol/L,最佳时间均为48 h。与阴性对照组相比,MA140μmol/L组和他莫昔芬35μmol/L组的细胞凋亡率,细胞荧光相对强度以及LC3Ⅱ/Ⅰ、Beclin-1蛋白相对表达水平均升高(P<0.05,P<0.01);PCNA、P62蛋白相对表达水平降低(P<0.05,P<0.01)。与MA 140μmol/L组相比,他莫昔芬35μmol/L组细胞凋亡率、细胞荧光相对强度以及Beclin-1蛋白相对表达水平明显升高(P<0.01),PCNA蛋白相对表达水平明显降低(P<0.01)。阴性对照组MCF-7细胞膜完整,核膜清晰,细胞形态良好;MA 140μmol/L组细胞膜、细胞核形态不规则,线粒体基质密度较高、嵴扩张,可见自噬小体;他莫昔芬35μmol/L组细胞膜局部溶解、破损,可见双核仁,线粒体肿胀、基质溶解,可见自噬小体。结论MA可抑制乳腺癌MCF-7细胞的增殖、诱导细胞凋亡和自噬。

LMAN2在HR阳性乳腺癌组织中的表达与患者预后的关系及其对MCF-7细胞增殖和迁移的影响

目的:探究甘露糖结合凝集素2(LMAN2)在激素受体(HR)阳性乳腺癌组织中的表达水平与乳腺癌患者预后的关系及其对MCF-7细胞增殖和迁移的影响。方法:通过TCGA、Bc-GenExMiner、GEPIA和Kaplan-Meier Plotter数据库分析LMAN2在乳腺癌组织和正常乳腺组织中的差异性表达及其与患者预后的关系。采用小RNA干扰技术将si-LMAN2#1、si-LMAN2#2及si-NC转染至MCF-7细胞,将过表达LMAN载体(pc-LMAN)及空载体pcDNA3.1阴性对照(pc-NC)转染至MCF-7细胞,实验分为si-LMAN2#1、si-LMAN2#2、si-NC、pc-LMAN2和pc-NC组。通过qPCR和WB实验检测各组细胞中LMAN2 mRNA和蛋白的表达水平,CCK-8、克隆形成、Transwell迁移、WB等实验检测敲低和过表达LMAN 2对MCF-7细胞增殖、克隆形成、迁移及AKT信号通路相关蛋白表达的影响。结果:LMAN2在乳腺癌组织中的表达水平显著高于正常乳腺组织(P<0.001)。HR阳性乳腺癌组织中LMAN2表达水平显著高于HR阴性乳腺癌组织(P<0.001);LMAN2高表达与HR阳性乳腺癌患者不良预后有关联。敲低LMAN2可显著降低MCF-7细胞的增殖和迁移能力(P<0.01或P<0.001),过表达LMAN2可显著提高MCF-7细胞的增殖和迁移能力(均P<0.001)。敲低LMAN2组MCF-7细胞中PTEN和P21蛋白表达水平均显著升高,p-AKT蛋白表达水平显著降低(均P<0.01)。结论:LMAN2在乳腺癌组织和HR阳性乳腺癌组织中高表达,且与不良预后有关联。LMAN2高表达与MCF-7细胞增殖和迁移有关联,其作用机制可能涉及AKT信号通路。

菊藻丸含药血清调控PTEN对乳腺癌MCF-7细胞生长和转移的作用研究

目的 研究菊藻丸含药血清调控10号染色体上缺失的磷酸酶和张力蛋白同源物基因(PTEN)对人乳腺癌MCF-7细胞生长和转移的作用。方法 8周龄、体重(200±20)g的SPF级Wistar雌性大鼠12只,采用随机数字表法分为菊藻丸组和对照组,各6只。各组分别以5.4 g/(kg·d)菊藻丸和等量生理盐水灌胃,制备含药血清和空白对照血清。将培养好的人乳腺癌MCF-7细胞分为20%空白血清组、5%含药血清组、10%含药血清组、15%含药血清组和20%含药血清组,分别使用含20%空白对照血清和含5%、10%、15%、20%含药血清的培养基进行培养干预。采用CCK-8检测细胞增殖、集落形成实验观察克隆形成能力、TUNEL染色检测凋亡、流式细胞术检测周期分布、划痕实验和Transwell检测细胞迁移和侵袭能力,q PCR和Western blot检测PTEN m RNA和蛋白表达水平。结果 与20%空白血清组比较,10%、15%、20%含药血清组细胞增殖活性降低、克隆形成率减少、侵袭能力降低(P<0.05);5%、10%、15%、20%含药血清组细胞凋亡水平升高、迁移能力降低、细胞周期阻滞于G1期、PTEN的m RNA和蛋白表达水平均升高(P<0.05)。与5%含药血清组比较,10%、15%、20%含药血清组细胞增殖活性降低、克隆形成率降低、细胞凋亡水平升高、迁移能力降低、侵袭能力降低、细胞周期阻滞于G1期、PTEN m RNA和蛋白表达水平均升高(P<0.05)。结论 菊藻丸含药血清能抑制MCF-7细胞生长和转移,其机制可能与激活PTEN的表达有关。

Dietary Daidzein Enhances Antiapoptotic Effect of 17β-Estradiol (E_2) on Breast Cancer MCF-7 Cells

Objective： To investigate whether dietary daidzein interact with endogenous 17β-Estradiol （E2） to give rise to additive or inhibitory effects on proliferation and apoptosis in breast cancer cells. Methods： Cell cycle distribution and apoptosis induction were analyzed by using flow cytometry when breast cancer cell lines MCF-7 were cotreated with daidzein （1, 5 μmol/L） and E2 （0.1-10 nmol/L） for 5 days. Whether daidzein could alter E2-modulated mRNA expression of estrogen receptor alpha （ERα）, estrogen receptor beta （ERI3） and ERβ-estrogen response element （ERE） dependent transcription was investigated by RT-PCR and luciferase induction assays. The effects of daidzein on E2-modulated expression of proapoptotic p53, bax and antiapoptotic bcl-2 at both mRNA and protein levels were also investigated by RT-PCR and Western blot. Results： Daidzein enhanced the antiapoptotic effect in an Ea dose-dependent manner, but had no effect on E2-induced proliferation. Daidzein antagonized E2-induced ERβ mRNA expression and ERβ-ERE dependent transcription. In addition, daidzein only antagonized E2-upregulated expression of p53 and bax, but had no effect on E2-upregulated expression of bcl-2. Conclusion： Daidzein enhances the antiapoptotic effect of E2 on breast cancer cells by inhibiting E2-mediated p53-bax proapoptotic pathway. These results suggest that dietary daidzein may enhance deleterious effect of endogenous E2 in hormone-dependent breast cancer.

A Variant of Human Estrogen Receptor-α,hER-α36 Weakens Docetaxel Drug Efficacy against Human Breast Cancer Cell Line MCF-7

Objective： hER-α36 is a variant of estrogen receptor-a, identified and cloned by a team of American. This research is to determine whether hER-α36 can enhance or weaken chemosensitivity to docetaxel in breast cancer cell line MCF-7（ERα66 positive）. Methods： RT-PCR was used to detect the expressions of ERα66 and ERa36 in the two human breast cancer cell lines MCF-7（MCF-7/ERα66） and MCF-7 transfected with ERa36（MCF-7/ERα36）. The two cell lines were treated with docetaxel（0-100umol/L）, and cell growth and apoptosis were evaluated using MTT （3-（4,5-dimethylthiazol- 2-yl）-2,5-diphenyl tetrazolium bromide） assay （using adriamycin （0-50umol/L） as the control） and flowcytometry. Western blot analysis was used to measure the effect of docetaxel on phosphor-ERKl/2 expression in the two cell lines. Results： The expressions of ERct36 and ERα66 were detectable in both MCF-7/ERα66 and MCF-7/ERα36 cell lines, while the expression of ERα36 in MCF-7/ER36 cells was higher. Both docetaxel and adriamycin inhibited the proliferation of both cells lines in a dose and time dependent manner. In comparison with MCF-7/ERα36 cell line, the MCF-7/ERα66 cells produced greater growth inhibition and apoptosis after treatment with docetaxel, but there was no significant difference in growth inhibition between the two cell lines treated with adriamycin; The MCF-7/ERα36 cell line resulted in a significant activation （phosphorylation） of ERK1/2 after treatment with docetaxel in a dose-dependent manner, but in the MCF-7/ERα66 cell line , a decrease in the level of phosphor- ERK1/2 expression was observed as the dose of docetaxel increased. Conclusion： ERa36 may be an agent that weakens chemosensitivity to docetaxel in breast cancer, probably by activating the expression of ERKI/2.

TO901317经LXRα/NF-κB抑制MCF-7乳腺癌细胞迁移

目的探究肝X受体(LXR)激动剂TO901317对MCF-7人乳腺癌细胞迁移能力的作用及机制。方法体外培养MCF-7细胞。先运用不同浓度的TO901317处理MCF-7细胞24 h,然后通过LXRαsiRNA转染或核因子κB(NF-κB)抑制剂PDTC处理细胞,划痕愈合实验检测MCF-7细胞迁移能力的改变,同时运用蛋白免疫印迹法检测LXRα、NF-κB p65与IκBα的表达。结果随着TO901317处理浓度的增加,MCF-7细胞的迁移能力明显得到抑制,差异具有统计学意义(P<0.05);同时LXRα与IκBα的表达逐渐增强,而NF-κB p65的表达则显著降低。LXRαsiRNA可显著延缓TO901317的上述作用,PDTC处理则进一步增强TO901317对乳腺癌细胞迁移的抑制作用。结论TO901317可激活LXRα,下调NF-κB p65、上调IκBα的表达,抑制乳腺癌细胞迁移。

Triterpenoid of avocado (Persea americana) seed and its cytotoxic activity toward breast MCF-7 and liver HepG2 cancer cells

Objective:To determine the structure of triterpenoid isolated from avocado seeds and the cytotoxic effect on MCF-7 and Hep G2 cells.Methods:The powder sample was macerated with ethanol,followed with separation of the extract by column chromatography.The target compound was monitored on thin layer chromatography plate and reagent Lieberman–Buchard.The isolated compound was characterized by spectral analysis,mainly ultraviolet,infrared,and liquid chromatographymass spectroscopy and their spectroscopic data with those reported in literature were compared.In vitro cytotoxic activity was investigated against Vero,MCF-7,and Hep G2 cell lines using MTT assay.Results:A triterpenoid compound was isolated from ethanol extract.The extracts,fraction(F3),and the isolated compound showed a significant cytotoxic activity against all investigated cell lines.MTT assay showed that the triterpenoid isolate inhibited cell proliferation of MCF-7 and Hep G2 cell line with the IC50 values of 62 mg/m L and 12 mg/m L,respectively,and was safe to normal cells.Conclusions:The results of the present study reveal that triterpenoid from avocado seeds have the potential for further development as anticancer agents.

Inhibition of cell proliferation by siRNA targeting hPRLR in breast cancer MCF-7 cell line

Objective： To study the inhibition of proliferation of breast cancer by small interfering RNA（siRNA） targeting human prolactin （hPRLR） and the underlying mechanisms. Methods：The siRNA targeting hPRLR was chemically synthesized and transfected into MCF-7 cells, the expression of hPRLR was analyzed by real-time quantitive PCR, cell growth inhibition was measured with MTT assay, cell cycle of the transfected cells was examined by flow cytometry, meanwhile, expression of cyclin D1 was tested by semi-quantitative RT-PCR, Results：24 h after transfection with 100 nmol/L siRNA-PRLR, the expression of hPRLR mRNA was suppressed by 65%, cells in G1 phase increased, but cells in S phase decreased. Down regulated hPRLR expression exhibited significant inhibition in cell proliferation. And the expression of cyclin D 1 was down regulated. Conclusion：The results indicate that siRNA-hPRLR is a useful tool for silencing hPRLR expression and inhibiting cell proliferation in breast cancer MCF-7 cell line, and it may be a possible new approach for breast cancer gene therapy.

Soy isoflavone extracts stimulate the growth of nude mouse xenografts bearing estrogen-dependent human breast cancer cells(MCF-7)

We explored the effects of different lifetime exposures to soy isoflavone extracts on the growth of estrogen- dependent human breast cancer cells （MCF-7） implanted into athymic mice of different ovarian statuses. The athymic mice, ovariectomized or not, were implanted with MCF-7 cells. Mice were fed with low, moderate and high doses of soy isoflavone extract, at dietary concentrations of 6.25, 12.5 and 25 g/kg, in different reproductive models, respectively. The expression of ki-67 was detected by immunohistochemistry, pS2 expression in tumors was analyzed by real-time PCR. Estrogen level in the serum was measured by chemiluminescence enzyme im- munoassay. Total genistein and daidzein levels in serum and urine were determined by liquid chromatography- electrospray tandem mass spectrometry （LC-ES/MS/MS）. In Group A, on week 4, nude mice were exposed to different doses of soy iosflavone extracts. In Group B, the experimental diets were given to the nude mice follow- ing ovariectomy and tumor implantation. In both groups, 6.25 and 12.5 g/kg soy isoflavone extracts stimulated the growth of MCF-7 xenografts, increased pS2 expression, proliferation and estrogen level in serum. In both Group B （postmenopausal mouse model） and Group C （premenopausal mouse model）, soy isoflavone extracts at doses of 6.25 and 12.5 g/kg showed stimulatory effects on the growth of MCF-7 tumors. In conclusion, administration of soy isoflavone extracts at doses of 6.25 and 12.5 g/kg during adolescence or later in life stimulated tumor growth in both menopausal and postmenopausal mouse models.

QCM Detection of Adhesion, Spreading and Proliferation of Human Breast Cancer Cells (MCF-7) on a Gold Surface

The quartz crystal microbalance （QCM） was used to monitor the one-day incubation of human breast cancer cells （MCF-7） on the gold electrode. In combination with an optical microscope simulation experiment, the cell-population pictures at various stages, the QCM responses to the cells＇ adhesion, spreading and proliferation on the electrode surface were discussed. The △f0 and △R1 responses were found mainly from mixed effects of viscodensity and surface stress, and in proportion to the cell coverage, rather than to the number of cells at the electrode. The significant fore-and-aft changes in cyclic voltammetry and electrochemical impedance spectroscopy of the ferri-ferrocyanide redox couple also proved that the cells were adhesion to the gold surface.

Cytotoxic Activity of <i>Thelesperma megapotamicum</i>Organic Fractions against MCF-7 Human Breast Cancer Cell Line

Thelesperma megapotamicum (Asteraceae) is commonly used in Argentine to treat various diseases (renal, digestive affections, and as anaesthesia). The present study showed the mechanisms involved “in vitro” cytotoxicity of T. megapotamicum Fractions. Five Fractions (F1 - F5) were separated by column chromatography (Silica gel) using hexane:diethyl ether as eluents. Viability was evaluated in Human breast carcinoma cell line (MCF-7) by staining with crystal violet. With respect to F1 Fraction treatment, the cell survival was 49.14% ± 8.87%, while the F2 and F3 ones exhibited a strong reduction of cell viability to only 26.35% ± 1.63% and 23.3%1 ± 0.53% of the control cell at 50 μg/ml, respectively. Apoptotic effect of these Fractions was detected using FITC-labeled Annexin V and propidium iodide binding assays and was confirmed by a higher proportion of apoptotic cells due to F2 and F3 treatments. T. megapotamicum active Fractions could facilitate the tumoral cells death by decreasing the activity of the enzyme Gamma-glutamyltranspeptidase and causing alteration in cell membrane sialoglycoconjugates and others involved anticancer mechanisms including apoptosis.

Sonic Hedgehog stimulates migration of MCF-7 breast cancer cells through Rac1

As one of the most common tumors in women, breast cancer has drawn considerable interest from investigators and clinicians in recent years. Despite early diagnosis and best therapeutic regimens available, the prognosis of malignant or metastatic breast cancer patients is still not optimistic. Hedgehog signaling, a classical pathway indispensable to embryonic development, participates in the growth of a variety of tumors. In the present study,the effect of Sonic Hedgehog(Shh) on breast cancer cells was investigated. We identified that Shh signal stimulated the migration of MCF-7 breast cancer cells. Smo and Gli1 were involved in Shh-stimulated migration of MCF-7 cells. Activating Smo and Gli1 induced cell migration, which was blocked by their specific antagonists.The effect of Shh signaling on MCF-7 cells was independent of Wnt5 a, Dvl2 and Rab35, but directly dependent on Rac1. In conclusion, our study suggested that Shh promotes breast cancer cell migration via Rac1 independently of the non-canonical Wnt signaling pathway, which may represent a rational molecular target for combination medication in breast cancer.

REVERSION OF MULTIDRUG RESISTANCE IN THE P-GLYCOPROTEIN POSITIVE BREAST CANCER CELL LINE(MCF-7/ADR) BY INTRODUCTION OF HAMMERHEAD RIBOZYME

A hammerhead ribozyme which site-specifically cleaved the GUC position in canon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function of the P-Gp as an ATP-dependent pump. A DNA sequence encoding the ribozyme gene was then incorporated into a eukaryotic expression vector (pH Apr-1 neo) and transfected into the breast cancer cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype. The ribozyme was stably expressed in the cell line by the RNA dot blotting assay. The result of Northern blot assay showed that the expressed ribozyme could decrease the level of mdrl mRNA expression by 83. 5 %; and the expressed ribozyme could inhibite the formation of p-glycoprotein detected by immuno- cy-tochemistry assay and could reduce the cell’s resistance to adrimycin; this means that the resistant cells were 1 000-fold more resistant than the parental cell line(MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line. These results show that a potentially useful tool is at hand which may inactivate MDR1 mRNA and revert the multidrug resistance phenotype.

Breast Cancer MCF-7 Cell Spheroid Culture for Drug Discovery and Development

In vitro 3D cancer spheroids (tumoroids) exhibit a drug resistance profile similar to that found in solid tumors. 3D spheroid culture methods recreate more physiologically relevant microenvironments for cells. Therefore, these models are more appropriate for cancer drug screening. We have recently developed a protocol for MCF-7 cell spheroid culture, and used this method to test the effects of different types of drugs on this estrogen-dependent breast cancer cell spheroid. Our results demonstrated that MCF-7 cells can grow spheroid in medium using a low attachment plate. We managed to grow one spheroid in each well, and the spheroid can grow over a month, the size of the spheroid can grow over a hundred times in volume. Our targeted drug experimental results suggest that estrogen sulfotransferase, steroid sulfatase, and G protein-coupled estrogen receptor may play critical roles in MCF-7 cell spheroid growth, while estrogen receptors α and β may not play an essential role in MCF-7 spheroid growth. Organoids are the miniatures of in vivo tissues and reiterate the in vivo microenvironment of a specific organ, best fit for the in vitro studies of diseases and drug development. Tumoroid, developed from cancer cell lines or patients’ tumor tissue, is the best in vitro model of in vivo tumors. 3D spheroid technology will be the best future method for drug development of cancers and other diseases. Our reported method can be developed clinically to develop personalized drugs when the patient’s tumor tissues are used to develop a spheroid culture for drug screening.

Studies on mechanism of cis9,trans11-CLA and trans10,cis12-CLA inducing apoptosis of human breast cancer cell line MCF-7

Objective： The aim of the study was to explore the activities of cis9, trans11-CLA （C9, t11-CLA） and transl0, cis12-CLA （t10, c12-CLA） inhibiting tumor, and investigate their relationships with PPARy and apoptotic proteins, and mechanism of anti-cancer. Methods： The inhibitory rate, cell growth curve and apoptotic morphological observation of MCF-7 cells were obtained by MTT assay, trypan blue staining and Hoechst33342 fluorescence staining. The apoptotic rate and cell cycle were detected with flow cytometry. Transcriptional level of genes was detected with RT-PCR semi-quantitative method, and Western blot was performed to detect proteins levels. Results： The two CLA isomers could reduce cell proliferation （P 〈 0.05）, increase apoptotic rate （P 〈 0.05）, and increase obviously the transcriptional and protein levels of PPARy （P 〈 0.01）. The synchronism and correlation between the effects of CLA to PPARy and apoptotic proteins Bax, Bcl-2, Caspase 3 changes were found with the dose- and time-dependent manners. There was cooperative relation between the levels of PPARy and the rates of Bax/Bcl-2, Caspase 3 （small fragment） by experiments of PPARy inhibitor GW9662 and ligand Rosiglitazone. Conclusion： The apoptotic pathway of PPARy-Bcl-2-Caspase 3 signaling was found. The C9, t11-CLA and tl0, c12-CLA could inhibit MCF-7 cell proliferation and promote apoptosis via activating PPARy-Bcl-2-Caspase 3 pathway. CLA may be a kind of activator of PPARv.