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.

Effects of bisphenol compounds on the growth and epithelial mesenchymal transition of MCF-7 CV human breast cancer cells

Bisphenol-A（BPA） has been considered as an endocrine disrupting chemical（EDC） because it can exert estrogenic properties.For bisphenol-S（BPS） and bisphenol-F（BPF） that are BPA analogs and substitutes,their risk to estrogendependent cancer has been reported rarely compared with the numerous cases of BPA.In this study,we examined whether BPA,BPS,and BPF can lead to the proliferation,migration,and epithelial mesenchymal transition（EMT） of MCF-7 clonal variant（MCF-7 CV） breast cancer cells expressing estrogen receptors（ERs）.In a cell viability assay,BPA,BPS,and BPF significantly increased proliferation of MCF-7 CV cells compared to control（DMSO） as did17β-estradiol（E2）.In Western blotting assay,BPA,BPS,and BPF enhanced the protein expression of cell cycle progression genes such as cyclin D1 and E1.In addition,MCF-7 CV cells lost cell to cell contacts and acquired fibroblast-like morphology by the treatment of BPA,BPS,or BPF for 24 hours.In cell migration assay,BPA,BPS,and BPF accelerated the migration capability of MCF-7 CV cells as did E2.In relation with the EMT process,BPA,BPS,and BPF increased the protein expression of N-cadherin,while they decreased the protein expression of Ecadherin.When BPA,BPS,and BPF were co-treated with ICI 182,780,an ER antagonist,proliferation effects were reversed,the expression of cyclin D1 and cyclin E1 was downregulated,and the altered cell migration and expression of N-cadherin and E-cadherin by BPA,BPS,and BPF were restored to the control level.Thus,these results imply that BPS and BPF also have the risk of breast cancer progression as much as BPA in the induction of proliferation and migration of MCF-7 CV cells by regulating the protein expression of cell cycle-related genes and EMT markers via the ER-dependent pathway.

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.

Effects of Volatile Oils of Sichuan Citrisarcodactylis fructus on Proliferation and Apoptosis of MCF-7 Human Breast Cancer Cells

[Objectives] To study the effects of volatile oils of Sichuan Citrisarcodactylis fructus on proliferation and apoptosis of MCF-7human breast cancer cells.[Methods]CCK-8 method was used to measure the cell proliferation,the flow cytometry was used to measure changes in cell cycle,Western blot was used to detect p53 and cyclin D1 activity changes,TUNEL method was used to measure percentage of apoptotic cells,inverted phase contrast microscope and transmission electron microscope were used to observe morphology of MCF-7 cells treated with different concentrations.[Results]When the concentration was 5-50 μmol/L,the cell proliferation inhibition rate increased significantly(P <0. 05),G2/M phase decreased significantly( P < 0. 05),eventually disappeared completely,G1 phase significantly increased with time and concentration( P < 0. 05),finally reached 90. 0%; the activity of cyclin D1 significantly declined( P < 0. 05),while the activity of p53 had no significant change( P > 0. 05). The apoptotic rate of MCF-7 cells significantly increased with the extension of time( P < 0. 05). At6 h,12 h and 24 h of action time,the apoptotic rate of MCF-7 cells significantly increased with the increase in volatile oil concentration(P <0. 05). Morphological observation showed that the apoptosis of MCF-7 cells was obvious.[Conclusions]The volatile oils of Citrisarcodactylis fructus have obvious inhibition of proliferation of MCF-7 cells and function of inducing apoptosis,and the effects took on the dose and time dependent. 5-50 μmol/L volatile oil of Sichuan Citrisarcodactylis fructus can inhibit the proliferation of MCF-7 cells and induce the apoptosis of MCF-7 cells through inhibiting the cyclin D1.

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.

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.

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.

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.

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.

Effects on Cell Viability and on Apoptosis in Tumoral(MCF-7)and in Normal(MCF10A)Epithelial Breast Cells after Human Chorionic Gonadotropin and Derivated-Angiotensin Peptides Treatments

Angiotensin-(1 - 7) [Ang-(1 - 7)] is an endogenous heptapeptide hormone of the renin-angiotensin system that has antiproliferative properties. The aim of this work was to evaluate the anti-proliferative and pro-apoptotic properties of Ang-(1 - 7) and of Ang-(1 - 7)-substituents 9-fluorenylmethyloxycarbonyl (Fmoc) e Ang II-derivatives containing the TOAC (2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid) in normal (MCF10A) and in tumoral (MCF7) epithelial mammary cell lines. Both cell lines received an hCG and angiotensin peptides 24-hour treatment, in combination or alone followed by cell viability, apoptosis and cell cycle assays performed by flow cytometer (GUAVA). After hCG, Ang-(1 - 7), hCG + Ang-(1 - 7) and hCG + Ang-(1 - 7)-Fmoc treatments, MCF7 displayed cell viability decrease and mid-apoptosis increase. We also observed cell viability decrease in MCF10A after Ang-(1 - 7), Ang-(1 - 7) Fmoc and hCG + AngII Toac treatments. These cells had an increase in late apoptosis and necrosis after AngII Toac, hCG + Ang-(1 - 7) and hCG + Ang-(1 - 7)-Fmoc treatments. Regarding the cell cycle analysis, we did not observed any changes in cell cycle phases. In summary, cell viability was decreased and apoptosis (initial, mid and late) was increased after hCG and/or Ang-(1 - 7) peptides treatments. These results point out hCG and Ang-(1 - 7) as effective compounds to inhibit cell proliferation, since they decrease cell viability and increase apoptosis in both normal and in tumoral breast cells, being the effect more pronounced in the tumoral cell line. Our results support the idea of investigating more closely the putative use of these compounds as novel therapeutic agents for breast cancer.

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.

Doxorubicin Induces Apoptosis through down Regulation of miR-21 Expression and Increases miR-21 Target Gene Expression in MCF-7 Breast Cancer Cells

miRNAs play an important regulatory role in variety of cellular functions and several diseases, including cancer. MicroRNA-21 (miR-21) is overexpressed in almost all types of human cancers. Studies revealed that the knockdown of miR-21 results in reduced tumor cell growth, cell cycle arrest and cell apoptosis. In this study, we evaluated the effect of doxorubicin on miR-21 expression in mcf-7 breast cancer cells. miRNA was extracted from mcf-7 cells treated with doxorubicin and untreated cells using miRNeasy Kit (Qiagen) according to the manufacturer’s instructions. cDNA synthesis was performed using miScript II RT Kit (Qiagen) and Real Time-PCR was performed using Real Q Plus 2x Master Mix Green-(Ampliqon, Denmark). The relative expression of miR-16 and miR-21 was calculated using comparative Ct method. All tests were run in triplicate to minimize the experimental errors. Samples with a Ct > 37 were excluded from the analysis. Statistically, a significant decrease in cell proliferation of mcf-7 cells was found in doxorubicin group compared with control groups 24 hours after transfection, dose dependently (p value< 0.001). After 24 hours, Doxorubicin (100 μm) significantly decreased miR-21 expression in mcf-7 cells (p = 0.0001). Also, the expression of caspase 9 significantly increased after Doxorubicin (100 μm) treatment (p = 0.0003). Together, these findings indicate that miR-21 plays a key role in regulating cell apoptosis in mcf-7 cells and may serve as a target for effective therapies.

Study on Cisplatin Aggravating DNA Damage and Causing a High Apoptosis Rate on Breast Cancer MCF-7 Cells

[Objectives] To investigate the mechanism of DNA damage of cisplatin( DDP),a broad spectrum anticancer drug on breast cancer MCF-7 cells,and to study the mechanism of apoptosis induced by DDP.[Methods]MCF-7 cells were treated by DDP( 0 mg/L,2 mg/L,4 mg/L,6 mg/L,6 mg/L,and 10 mg/L) for 48 hours. MTT assay was used to detect the inhibitory effect of DDP on MCF-7 cells and IC50 value was calculated. Western blot was adopted to detect the expression of γ-H2 AX,which was the marker of DNA double stranded breaks( DSBs) and ATM( sensory molecules of DSBs),the apoptotic signal transduction molecule cleaved caspase-3,and the proteins associated with apoptosis calpain.[Results]DDP inhibited MCF-7 cell activity in a concentration-dependent manner and IC50 was 7. 57 mg/L. In contrast to the control group( without DDP treatment),MCF-7 cells with DDP treatment expressed more γ-H2 AX,ATM,cleaved caspase-3 and calpain.[Conclusions] DDP could inhibit the activity of breast cancer MCF-7 cells. Its mechanisms may be associated with inhibition of MCF-7 cell apoptosis,induction of DNA double strand breaking and the expression of pro-apoptotic protein up-regulation.

The Evaluation of the Effects of Temozolomide on MGMT Gene Expression in MCF-7 and SKBR3 Human Breast Cancer Cell Lines

Background and Aim: In this study, it was aimed to examine the cytotoxic effect of temozolomide (TMZ) treatment, on MCF-7 and SKBR3 cell lines, to study the methylation levels of MGMT gene expression and gene promoter region. Methods: The MTT test was performed to determine the effective dose of TMZ. The time-dependent cell survival test was performed after the IC50 value was found. Western blotting was performed to determine MGMT gene expression levels. High Resolution Melting (HRM) technique was used to determine the methylation levels of MGMT gene promoter region. Results: TMZ has been shown to have a high cytotoxic effect on SKBR3 cell line and low cytotoxicity on MCF-7. When MGMT expression levels before and after TMZ treatment were observed by western blotting, the gene expression levels of TMZ treatment were shown to decrease in both cell lines. It was observed that MGMT gene promoter region was hypermethylated in two cell lines, and that the application of TMZ further increased the methylation levels in the promoter region. Conclusions: It was seen that TMZ could be used as a single agent in SKBR-3 cell line. With this study on breast cancer, it is expected that temozolomide treatment will lead future in vitro and in vivo studies for breast cancer.

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。

EGFR antisense RNA blocks expression of the epidermal growth factor receptor and partially reverse the malignant phenotype of human breast cancer MDA-MB-231 cells

The effects of human EGFR to the malignant phenotype of human breast cancer cell line MDA-MB-231 were investigated experimentally. A retroviral vector containing a 5'1350bp fragment of the human EGFR cDNA in the antisense orientation was transfected into targeted cells by lipofectamine. The effects on cell proliferation, cell cycle and adherent ability to extracellular matrix (ECM) components were studied after the expression of antisense transcripts to EGFR 5'1350bp fragment in target cells. In vitro studies showed that the growth ability of the transfected cells was partialy inhibited in comparison to parental cells and to cells transfected with the plasmid containing the neomycin resistance gene only. It was found that EGF (10ng/ml) had an augmenation effect on the growth of transfected MDA-AS10 cells but not MDA-MB-231 cells.Flow cytometric analysis showed that the cell cycle of the transfected cells was abnormal with a decrease of cells in G2/M and S phases and an increase of cells in G1 phase,indicating a blockage in phase G1. Immunofluorescence of EGFR expression in transfectants stained with an antiEGFR antibody was decreased and their growth in soft agarose was also severely impaired. The transfected cells showed less adherence to laminin (LN) and fibronectin (FN). In short, EGFR antisense RNA decreases the expression of EGFR on MDA-MB-231 cells and partially reverses their malignant phenotype as well.Effects of antisense EGFR on human breast cancer MDA-MB-231 cells

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.

Piperine suppresses growth and migration of human breast cancer cells through attenuation of Rac1 expression

Objective:To investigate the effect of piperine on human breast cancer cells.Methods:The effect of piperine on proliferation and migration of human breast cancer cells,MCF-7 and MDA-MB-231,was investigated using colony formation assays,wound healing assays,Matrigel migration assays,flow cytometry,RT-qPCR,and Western blotting assays.Results:Piperine inhibited the growth of MCF-7 and MDA-MB-231 cells and suppressed colony formation.Cell reduction at the G_(0)/G_(1) phase and cell arrest at the G_(2)/M phase were observed in breast cancer cells.However,the significant effect was only demonstrated in MDA-MB-231 cells.Moreover,cancer cell migration was suppressed by piperine at low concentration.RT-qPCR and Western blotting assays showed that piperine downregulated Rac1 gene and protein expression.Conclusions:Piperine could inhibit growth and migration of breast cancer cells by reducing Rac1 gene and protein expression.

Let-7 miRNA and CDK4 siRNA co-encapsulated in Herceptin-conjugated liposome for breast cancer stem cells

Recently,breast cancer stem cells(BCSCs)have rapidly emerged as a novel target for the therapy of breast cancer as they play critical roles in tumor growth,maintenance,metastasis,and recurrence.Let-7 miRNA is known to be downregulated in a variety of cancers,especially BCSCs,whereas CDK4 being overexpressed in human epidermal growth factor receptor 2(HER-2)overexpressing tumor cells.In this study,let-7 miRNA and CDK4-specific siRNA were chosen as therapeutic agents and co-encapsulated in Herceptinconjugated cationic liposomes for breast cancer therapy.Particle size,zeta potential,and encapsulation efficacy of mi/siRNA-loaded PEGylated liposome conjugated with Herceptin(Her-PEG-Lipo-mi/siRNA)were 176 nm,28.1 mV,and 99.7%±0.1%,respectively.Enhanced cellular uptake(86%)was observed by fluorescence microscopy when SK-BR-3 cells were treated with Her-PEG-Lipo-mi/siRNA.Also,the increased amount of let-7a mRNA and decreased amount of cellular CDK4 mRNA were observed by qRT-PCR when SK-BR-3 cells were treated with Her-PEG-Lipo-mi/siRNA,which was even more so when SK-BR-3 stem cells were used(197 vs 768 times increase for let-7a,62%vs 68%decrease for CDK4).Growth inhibition(65%)andmigration arrest(0.5%)of the cellswere achieved by the treatment of the cells with Her-PEG-Lipo-mi/siRNA,but not withmi/siRNA complex or other formulations.In conclusion,an efficient liposomal delivery system for the combination of miRNA and siRNA to target the BCSCs was developed and could be used as an efficacious therapeuticmodality for breast cancer.

Effects of Estradiol and Tamoxifen on Proliferation of Human Breast Cancer Cells and Human Endometrial Cells

The effects of estradiol and tamoxifen on the proliferation of estrogen receptor positive cells and the relationship between the tamoxifen tolerance and cell origin were investigated The tissues of human endometrium and breast cancer were randomly selected following dissection for primary cell culture After the breast cancer cells and endometrial cells were treated with 1×10 -8 mol/L estradiol and/or 1 ×10 -6 tamoxifen, 3H-labelled thymine nucleotide was used to trace the kinetics of cell proliferation There was no significant difference in the inhibition on the human endometrial cells between tamoxifen-treated group (6 3%) and control group (6 4%), but tamoxifen could significantly inhibit the proliferation of the human breast cancer cells (45 84%) as compared with control group (52 72%) Moreover, tamoxifen could significantly stimulate the proliferation of tamoxifen resistant breast cancer cells (9 64%) as compared with control group (6 32%) Estradiol could significantly stimulate the proliferation of all the three kinds of cells as compared with control group The combined use of estradiol and tamoxifen could inhibit the proliferation of the endometrial cells and breast cancer cells as compared with estradiol used alone, but on the tamoxifen resistant breast cancer cells, they could more significantly stimulate the proliferation than E2 It was concluded that E2 could stimulate the proliferation of these three kinds of cells However, the inhibitive effects of tamoxifen on the proliferation of these cells were dependent on the estradiol