Proteomics reveals protein profile changes in doxorubicin--treated MCF-7 human breast cancer cells

MCF-7 cells are extensively used as a cell model to investigate human breast tumors and the cellular mechanism of antitumor drugs such as doxorubicin (DOX), an anthracycline antitumor drug widely used in clinical chemotherapy. To understand the effects of DOX on the protein expression, we perform a comprehensive proteomics to survey global changes in proteins after DOX treatment in MCF-7 cells. Exposure of MCF-7 cells to 0.1 microM DOX for 2 days induced a differentiation-like phenotype with prominent perinuclear autocatalytic vacuoles, abundant filamentous material, and irregular microvilli at the cell surface. In this study, we also present a proteome reference map of MCF-7 cells with 21 identified protein spots via analysis of N-terminal sequencing, mass spectrometry, immunoblot and/or computer matching with protein database. Based on the proteome map, we found that DOX causes a markedly decrease in the levels of three isoforms of heat shock protein 27 (HSP27) whereas the levels of other stress associated proteins including HSP60, calreticulin, and protein disulfide isomerase were not significantly altered in DOX-treated MCF-7 cells. Taken together, we suggest that that action of DOX on breast tumor cells may be partly related to dysregulation of HSP27 expression. Modulation of HSP27 levels may be a clinically useful potential target for design of antitumor drugs and controlling breast tumor growth.     

Anti-apoptotic effect of claudin-1 in tamoxifen-treated human breast cancer MCF-7 cells

Background  

Claudin-1 is a membrane protein of tight junctions, and is associated with the development of various cancers. However, the significance of claudin-1 expression in cancer cells is not well understood. Here, we showed for the first time the anti-apoptotic effect of claudin-1 in human breast cancer MCF-7 cells.     

Growth stimulatory effect and metabolism of testosterone in MCF-7 human breast cancer cells

The purpose of our study was to evaluate the effect of testosterone and its metabolic pathway in MCF-7 cells in culture. Testosterone exhibited a dose-dependent (from 0.1 to 10 nM) and time-dependent (from 3 to 9 days) growth stimulation. The metabolic pathway was investigated following treatment with two testosterone concentrations: one stimulating (10 nM) and one not affecting (0.1 nM) cell growth. Celite column chromatography was used to separate H-3-testosterone metabolites, whose identity was confirmed by gas chromatography-mass spectrometry analysis. The main findings of the metabolic study were: i) recovery of a large amount of untransformed testosterone; ii) a high conversion of testosterone to conjugated, biologically inactive metabolites; iii) the highest level of Sa-diol among the metabolites of testosterone; iv) a conversion (2%) of testosterone into oestradiol, which resulted in a growth stimulatory concentration when testosterone was used at 10 nM. We conclude that in our experimental conditions androgens and oestrogens can concur to stimulate MCF-7 cell growth through androgen receptor-mediated and oestrogen receptor-mediated mechanisms.     

RhG-CSF对乳腺癌细胞MCF-7增殖作用的影响

目的：探讨人重组粒细胞集落刺激因子（RhG-CSF）对乳腺癌细胞株MCF-7的增殖作用的影响。方法：体外培养人乳腺癌细胞株MCF-7,将含不同浓度RhG-CSF的培养液与MCF-7细胞共同培养不同时间,采用MTT比色法计算细胞生长增殖率;Anexxin V/PI双染试剂盒检测细胞凋亡率。实验结果用SPSS.v16.0软件分析。结果：不同浓度RhG-CSF处理细胞后,可以显著促进MCF-7细胞株的增殖（P〈0.01）,且当浓度为10μg/L时增殖作用最强。同时各浓度的RhG-CSF亦可抑制MCF-7细胞凋亡（P〈0.01）。结论：RhG-CSF可以显著促进人乳腺癌细胞株MCF-7增殖。当浓度小于10μg/L时,增殖呈浓度依赖性。大于10μg/L时,增殖能力反而逐渐下降。同时RhG-CSF亦可抑制MCF-7细胞凋亡。     

RhG-CSF对乳腺癌细胞MCF-7增殖作用的影响

目的:探讨人重组粒细胞集落刺激因子(RhG-CSF)对乳腺癌细胞株MCF-7的增殖作用的影响。方法:体外培养人乳腺癌细胞株MCF-7,将含不同浓度RhG-CSF的培养液与MCF-7细胞共同培养不同时间,采用MTT比色法计算细胞生长增殖率;Anexxin V/PI双染试剂盒检测细胞凋亡率。实验结果用SPSS.v16.0软件分析。结果:不同浓度RhG-CSF处理细胞后,可以显著促进MCF-7细胞株的增殖(P<0.01),且当浓度为10μg/L时增殖作用最强。同时各浓度的RhG-CSF亦可抑制MCF-7细胞凋亡(P<0.01)。结论:RhG-CSF可以显著促进人乳腺癌细胞株MCF-7增殖。当浓度小于10μg/L时,增殖呈浓度依赖性。大于10μg/L时,增殖能力反而逐渐下降。同时RhG-CSF亦可抑制MCF-7细胞凋亡。     

Biosynthesis of alpha fetoprotein by MCF-7 human breast cancer cells

Direct evidence was obtained for de novo synthesis of AFP by MCF-7 human breast cancer cells per se. Synthesis was demonstrated by L-14C-leucine and L-35S-methionine incorporation into immunochemically isolated AFP, and confirmed by radioimmunodiffusion and radioimmunoelectrophoresis. This information indicates that AFP synthesis is associated with normal and neoplastic cells of several different histotypes, and suggests that AFP detected and measured previously in primary human breast cancer tissue cytosol (Sarcione et al., 1983) also resulted from in situ biosynthesis by breast cancer cells per se rather than uptake of exogenous AFP originating from extracellular sources. Evidence that AFP obtained after treatment of 14C-leucine radiolabelled MCF-7 breast cancer cell protein with 0.4 M KCl contained 2.6 times more radioactivity than did AFP obtained before such salt treatment is interpreted as indicating that two different molecular species of de novo synthesized AFP existed in breast cancer cells: (1) larger amount of non-immunoreactive AFP which became immunoreactive and measurable after KCl treatment, and (2) smaller amounts of free immunoreactive AFP. 14C-radiolabelled AFP obtained before and after treatment of cell protein with 0.4 M KCl codiffused, comigrated with alpha 1 electrophoretic mobility and gave an identical radioimmunologic reaction both with each other and with added carrier human cord serum AFP. Furthermore, preliminary studies indicated that radiolabelled non-immunoreactive AFP could be separated from lower-molecular-weight free AFP by chromatography on Sephadex G-200. Taken together, these findings suggest that synthesized free AFP was bound as a non-immunoreactive high-molecular-weight macromolecular complex rather than being covalently linked. Our current working hypothesis is that most of the de novo synthesized endogenous AFP in MCF-7 human breast cancer cells was rapidly and reversibly bound by hydrophobic bonding to a specific cytoplasmic AFP-receptor.     

Differential expression of microRNA expression in tamoxifen-sensitive MCF-7 versus tamoxifen-resistant LY2 human breast cancer cells

Microarrays identified miRNAs differentially expressed and 4-hydroxytamoxifen (4-OHT) regulated in MCF-7 endocrine-sensitive versus resistant LY2 human breast cancer cells. 97 miRNAs were differentially expressed in MCF-7 versus LY2 cells. Opposite expression of miRs-10a, 21, 22, 29a, 93, 125b, 181, 200a, 200b, 200c, 205, and 222 was confirmed. Bioinformatic analyses to impute the biological significance of these miRNAs identified 36 predicted gene targets from those regulated by 4-OHT in MCF-7 cells. Agreement in the direction of anticipated regulation was detected for 12 putative targets. These miRNAs with opposite expression between the two cell lines may be involved in endocrine resistance.     

人乳腺癌MCF-7细胞中SP亚群细胞的分离及其生物学行为研究

目的:了解肿瘤干细胞的生物学行为及相关的调控机制.方法:采用干细胞对Hoechst33342染料外排的特性进行MCF-7 细胞系肿瘤干细胞的流式分选.并对其增殖、自我更新、分化能力等生物学行为进行研究.还利用流式细胞仪、免疫荧光技术、荧光定量PCR等技术进行了与干细胞生物学行为密切相关的Wnt信号转导通路中相关分子的表达特征研究.结果:MCF-7细胞系中包含SP亚群(side population);且SP细胞具有分化潜能,高增殖能力,及自我更新特性;而且Wnt通路的各种关键分子在该细胞系SP亚群细胞中呈活化状态.结论:MCF-7细胞系的SP亚群可以代表该细胞系的肿瘤干细胞,Wnt通路在该肿瘤细胞系肿瘤干细胞的自我更新等其它生物学行为的调控中起重要作用.     

Effect of human chorionic gonadotropin in the gene expression profile of MCF-7 cells

The preventive effect of human chorionic gonadotropin (hCG)-induced differentiation on experimental mammary carcinogenesis has been reported to be due to the inhibition of cell proliferation, increased DNA repair capabilities of the mammary epithelium, decreased binding of the carcinogen to the DNA and activation of programmed cell death genes leading to apoptosis. To further our understanding of the molecular pathway of the hCG action on mammary epithelial cells we have analyzed gene expression profiles of MCF-7 cells treated with hCG for 24, 48, and 96 h, using a DNA microarray consisting of 1176 genes. Comparison of expression between the treated and not treated cells enabled us to identify 48 genes that are affected by this hormone. Importantly, there is a cluster of genes that are overexpressed during the first 24 h and level off thereafter, whereas other genes are maximally expressed at 96 h of treatment. The results obtained in this study demonstrated that genes regulating cell proliferation, apoptosis, cell trafficking, and DNA repair are significantly affected by hCG in human breast cancer cells in vitro.     

致康胶囊对人乳腺癌MCF-7细胞增殖及凋亡的影响

目的:探讨致康胶囊对人乳腺癌细胞系MCF-7增殖及凋亡的影响。方法:采用0（对照组）、0.5、1.0、2.0 mg/ml 致康胶囊培养液分别处理乳腺癌细胞MCF-7,分别于培养后24、48和72 h计数MCF-7细胞数。采用MTT法检测致康胶囊对乳腺癌MCF-7细胞生长增殖的影响;采用流式细胞仪检测细胞周期;PI 单染流式细胞仪检测致康胶囊对MCF-7细胞凋亡的影响。结果:不同浓度致康胶囊能有效地抑制MCF-7细胞增殖,且随浓度增加和作用时间延长,细胞的增殖抑制率增加。0.5、1.0、2.0 mg/ml的致康胶囊作用MCF-7细胞72 h后,G0/G1期细胞所占细胞周期的比例分别为19.33%±10.38%、14.12%±5.37%和26.84%±2.13%;而对照组G0/G1期比例为51.83%±1.90%。0.5、1.0、2.0 mg/ml致康胶囊处理48 h后细胞的凋亡率分别为2.09%±0.74%、3.84%±0.78%和 5.35%±0.83%。结论:致康胶囊能抑制MCF-7细胞的体外增殖,且抑制作用表现为时效和量效关系;并能通过阻滞细胞周期于G2/M期,促进乳腺癌细胞凋亡。     

慢病毒介导高表达OTUD7B对乳腺癌MCF-7细胞生物学行为影响

目的 去泛素化酶OTUD7B与肿瘤的发生、发展密切相关.为了明确OTUD7B在乳腺癌中所发挥的作用,实验利用慢病毒构建高表达OTUD7B载体感染MCF-7乳腺癌细胞后对其生物学行为的影响.方法 构建带有绿色荧光蛋白标签的人OTUD7B表达质粒的慢病毒(pEGFP-hOTUD7B)及对照(pEGFP-CI)感染MCF-7乳腺癌细胞;于荧光倒置显微镜下观察病毒转染效果及应用蛋白质印迹法及免疫组化法检测OTUD7B的表达水平;MTS法检测实验组(pEGFP-hOTUD7B)、阴性对照组(pEGFP-CI)和正常对照组对MCF-7乳腺癌细胞增殖能力的影响;应用细胞划痕实验检测细胞迁移能力;流式细胞仪检测细胞凋亡.结果 感染病毒后于荧光倒置显微镜下观察病毒感染效率,可见病毒感染成功.应用蛋白质印迹法检测病毒感染率并找出最适病毒感染复数(multiplicity of infection,MOI),当MOI=30时,实验组、阴性对照组和正常对照组灰度值分别为3.81±0.08、2.12±0.078和2.05±0.15,差异有统计学意义,F=402.03,P<0.001.应用免疫组化法可见感染OTUD7B表达水平.MTS法结果显示,实验组、阴性对照组和正常对照组细胞24 h A值分别为0.36±0.08、0.56±0.25和0.69±0.17,F=11.819,P<0.001;48 h A值分别为0.65±0.17、1.45±0.48和1.82±0.63,F=23.752,P<0.001;在72 h A值分别为0.73±0.21、1.58±0.63和1.99±0.27,F=35.563,P<0.001.细胞划痕试验显示,24 h后实验组组迁移率为(7.7±0.91)%,阴性对照组和正常对照组迁移率分别为(13.4±1.52)%和(12.1±1.32)%,F=49.36,P<0.001,48 h后实验组迁移率为(12.4±1.29)%,阴性对照组及正常对照组迁移率分别为(32.9±1.71)%和(31.8±1.59)%,F=504.50,P<0.001.流式细胞仪检测细胞凋亡结果提示,实验组与阴性对照组及正常对照组相比明显使细胞阻滞在G0/G1期,促进其凋亡,FG0/G1期=425.102,FS期=135.063,均P<0.001.结论 成功构建了能够高表达OTUD7B的慢病毒载体,明显抑制了MCF-7乳腺癌细胞增殖、迁移,并促进了其凋亡.     

Additive effect of mifepristone and tamoxifen on apoptotic pathways in MCF-7 human breast cancer cells

MCF-7 cells growing in culture were used to study the mechanism of the antiproliferative activity of the antiprogestin mifepristone, as compared with the antiestrogen 4-hydroxytamoxifen or the combination of both. These steroid antagonists induced a significant time- and dose-dependent cell growth inhibition (cytotoxicity). This inhibition of cell survival was associated with a significant increase in DNA fragmentation (apoptosis), downregulation of bcl2, and induction of TGF1 protein. Abrogation of the mifepristone- and/or 4-hydroxytamoxifen-induced cytotoxicity by TGF1 neutralizing antibody confirms the correlation between induction of active TGF1 and subsequent cell death. The effect of a combination of mifepristone and 4-hydroxytamoxifen on cell growth inhibition, on the increase in DNA fragmentation, bcl2 downregulation, and induction of TGF1 protein was additive and significantly different (P < 0.05) from the effect of monotherapy. A translocation of protein kinase C (PKC) activity from the soluble to the particulate and/or nuclear fraction appeared to be also additive in cells treated with a combination of both 4-hydroxytamoxifen and mifepristone. These results suggest that the mechanism of the additive antiproliferative activity of mifepristone and tamoxifen could be explained at least in part by an additive induction of apoptosis in both estrogen and progesterone receptor positive MCF-7 breast cancer cells. A bcl2 downregulation, the PKC transduction pathway, and TGF1 expression seem to be involved in this additive mechanism of action. Our data further suggest that a combination of an antiprogestin with tamoxifen may be more effective than tamoxifen monotherapy in the management of human breast cancer.     

Gold nanoparticles induce apoptosis in MCF-7 human breast cancer cells

Background: Gold nanoparticles have recently been investigated with respect to biocompatibility accordingto their interactions with cells. The purpose of this study was to examine cytotoxicity and apoptosis induction bywell-characterized gold nanoparticles in human breast epithelial MCF-7 cells. Methods: Apoptosis was assessedby TUNEL, cytotoxicity by MTT assay and caspase 3, 9, p53, Bax and Bcl expression by real-time PCR assays.Results: Gold nanoparticles at up to 200 μg/mL for 24 hours exerted concentration-dependent cytotoxicity andsignificant upregulation of mRNA expression of p53, bax, caspase-3 & caspase-9, whereas expression of antiapoptoticbcl-2 was down-regulated. Conclusion: To the best of our knowledge this is the first report showingthat gold nanoparticles induce apoptosis in MCF-7cells via p53, bax/bcl-2 and caspase pathways.     

The effect of Tc-99m-labeled MDM2 antisense oligonucleotide on gene expression in human breast cancer MCF-7 cells

To investigate the effect of radiolabed mouse double minute 2 (MDM2) antisense oligonucleotide on gene expression in human breast cancer MCF-7 cells, an antisense oligonucleotide (ASON) targeting MDM2 mRNA was synthesized and radiolabeled with 99Tcm. The labeling efficiency, radiochemical purity, and the ability of labeled ASON to hybridize to the sense oligonucleotides (SON) were investigated. To study whether the antisense probe hybridizes to respective sequence on MDM2 mRNA strand after radiolabeling, cells were incubated with radiolabeling oligonucleotides antisense oligonucleotide (0, 100, 500 nm/L) or mismatch oligonucleotide (ASONM) (500 nm/L) for 24 h, in the presence of Lipofectin 2000. RT-PCR and Western blotting was carried out to measure the MDM2 mRNA and protein levels. The antisense oligonucleotide was radiolabeled with the bifunctional chelator HYNIC at the labeling efficiency of 57.2 +/- 2.98% (n = 5) and the mismatch oligonucleotide was 56.3 +/- 3.01% (n = 5). The radiochemical purity was above 95% and labeled antisense oligonucleotide has the ability to hybridize to the sense oligonucleotide. The levels of mRNA and protein have significant differences in different concentration groups. The oligonucleotide can be successfully radiolabeled, and specially hybridized to the MDM2 mRNA and inhibit gene expression intensively as compared to mismatch oligonucleotide. This method will be very useful in the in vivo investigation of tumor targeting.     

Androgen regulation of prolactin-receptor gene expression in MCF-7 and MDA-MB-453 human breast cancer cells.

Lactogenic hormones which bind to the PRLR are likely to be growth-stimulatory in human breast-cancer cells. Oestrogen and progesterone control cellular expression of the PRLR; however, elevated androgen levels in some breast-cancer patients raised the possibility that androgens may also influence breast-cancer sensitivity to lactogenic hormones. This study investigated whether androgens could affect expression of the PRLR in the MCF-7 breast-cancer cell line. PRLR binding activity was increased approximately 2-fold by treatment for 24 hr with 10 nM R1881, TEST, DHT, MPA and ORG 2058. Northern analysis indicated that DHT also increased the level of PRLR mRNA. The antiprogesterone, RU 38486, displaced tritiated ORG 2058 binding but not tritiated DHT binding to MCF-7 cells; it completely antagonized ORG 2058 and partially antagonized R1881 induction of the PRLR, but had no effect on induction by DHT. The anti-androgen, RU 23908, displaced tritiated DHT binding but not tritiated ORG 2058 binding, and antagonized DHT and R1881 induction of PRLR but not induction of the PRLR by ORG 2058. These data indicated that ORG 2058 acting via the PR and DHT acting via the AR were able to induce PRLR expression in MCF-7 cells. In MDA-MB-453 cells, which express the AR but not the ER or PR, DHT and R1881 increased PRLR binding to 150% of control values at 0.1 nM. ORG 2058 was ineffective, demonstrating androgen induction of PRLR in the absence of PR and ER. These data indicate that PRLR can be regulated by androgens in MCF-7 and MDA-MB-453 human breast-cancer cells.     

Antioxidant and xenobiotic-metabolizing enzyme gene expression in doxorubicin-resistant MCF-7 breast cancer cells

We investigated the expression of the genes for several antioxidant and xenobiotic-detoxifying enzymes in the multidrug-resistant variant of the human breast cancer cell line MCF-7, MCF-7/Dox. MCF-7/Dox is greater than 500-fold resistant to doxorubicin by clonogenic assay. Enzyme activity determinations in the cytoplasmic compartment of MCF-7/Dox revealed a 25-fold increase in glutathione peroxidase level compared to the parent line (mean +/- SD, 10 +/- 2.8 versus 0.4 +/- 0.24 nmol/min/mg; P less than 0.005). The activity of the other major hydrogen peroxide-detoxifying enzyme, catalase, was diminished in MCF-7/Dox (2.0 +/- 0.4 versus 4.8 +/- 1.4 mumol/min/mg; P less than 0.025 compared to MCF-7). Superoxide dismutase activity did not differ between the two cell lines. The specific activity of the xenobiotic-detoxifying enzyme DT-diaphorase was 4-fold lower in MCF-7/Dox compared to MCF-7 (DT-diaphorase, 117 +/- 45 versus 509 +/- 123 nmol/min/mg; P less than 0.005). Daunorubicinol-producing carbonyl reductase activity was equal in the two lines. Northern blot analysis demonstrated a 0.9-kilobase band of glutathione peroxidase mRNA in MCF-7/Dox; no glutathione peroxidase mRNA was detected in MCF-7. A 2.4-kilobase catalase and 0.7- and 1.4-kilobase superoxide dismutase mRNAs were detectable in MCF-7/Dox and MCF-7. When normalized to 28S RNA, no difference in the mRNA levels of catalase and superoxide dismutase in MCF-7/Dox and MCF-7 could be determined. DT-diaphorase mRNAs of 1.4 and 2.7 kilobases were found in both MCF-7/Dox and MCF-7 cells. A 1.2-kilobase mRNA homologous to the putative carbonyl reductase cDNA was also easily detectable in both MCF-7 and MCF-7/Dox. The amount of mRNA for both xenobiotic-detoxifying enzymes was decreased 2- to 4-fold in the doxorubicin-resistant cells. Southern blot analysis of PstI- and MspI-restricted genomic DNA revealed no evidence for amplification or rearrangement of the glutathione peroxidase gene. These results indicate that, in addition to the previously described overexpression of anionic glutathione S-transferase in MCF-7/Dox cells, an augmented glutathione peroxidase mRNA level is the major alteration in antioxidant and xenobiotic-detoxifying enzyme expression that could contribute to doxorubicin insensitivity in these multidrug-resistant breast cancer cells.     

Melatonin enhances the inhibitory effect of aminoglutethimide on aromatase activity in MCF-7 human breast cancer cells

Summary The inhibition of the aromatase-induced intratumoral estrogen synthesis is one of the main anticancer pharmacological strategies. The aim of this paper was to study if a melatonin pretreatment prior to aminoglutethimide increases the efficiency of the aromatase inhibitor used in treating breast cancer. Aminoglutethimide (100 μM) and melatonin (1 nM) significantly decreased cellular aromatase activity in unpretreated MCF−7 cells. A sequential regimen of melatonin (1 nM) followed 24 h later by aminoglutethimide (100 μM) induced a significantly higher decrease in MCF-7 cell aromatase activity to below the values obtained in unpretreated cells. Melatonin treatment inhibited aromatase mRNA expression in unpretreated cells and a sequential treatment of cells with melatonin followed by aminoglutethimide induced a significant inhibition in the aromatase mRNA expression as compared to cells exposed to the same doses of aminoglutethimide, but without melatonin pretreatment.  The present study demonstrates that a treatment with melatonin followed by aminoglutethimide is the most effective way of reducing the aromatase activity in the MCF-7 cell line. The aminoglutethimide inhibitory effect is more potent when MCF-7 cells are pre-exposed to melatonin. Our results suggest that melatonin pretreatment increases the reduction of the aromatase activity of cells exposed to aminoglutethimide as a result of the decrease in the aromatase mRNA expression. The findings presented here point to melatonin pretreatment as a novel and interesting means to increase the efficacy of competitive aromatase inhibitors used in treating breast cancer.     

Antitumor activity of colloidal silver on MCF-7 human breast cancer cells

Background

Colloidal silver has been used as an antimicrobial and disinfectant agent. However, there is scarce information on its antitumor potential. The aim of this study was to determine if colloidal silver had cytotoxic effects on MCF-7 breast cancer cells and its mechanism of cell death.

Methods

MCF-7 breast cancer cells were treated with colloidal silver (ranged from 1.75 to 17.5 ng/mL) for 5 h at 37°C and 5% CO₂ atmosphere. Cell Viability was evaluated by trypan blue exclusion method and the mechanism of cell death through detection of mono-oligonucleosomes using an ELISA kit and TUNEL assay. The production of NO, LDH, and Gpx, SOD, CAT, and Total antioxidant activities were evaluated by colorimetric assays.

Results

Colloidal silver had dose-dependent cytotoxic effect in MCF-7 breast cancer cells through induction of apoptosis, shown an LD₅₀ (3.5 ng/mL) and LD₁₀₀ (14 ng/mL) (*P < 0.05), significantly decreased LDH (*P < 0.05) and significantly increased SOD (*P < 0.05) activities. However, the NO production, and Gpx, CAT, and Total antioxidant activities were not affected in MCF-7 breast cancer cells. PBMC were not altered by colloidal silver.

Conclusions

The present results showed that colloidal silver might be a potential alternative agent for human breast cancer therapy.     

人参多糖与他莫昔芬联合对人乳腺癌MCF-7细胞凋亡的影响及其机制研究

目的： 探讨人参多糖 (ginseng polysaccharide,GPS)与他莫昔芬 (tamoxifen,TAM)联合对人乳腺癌MCF-7细胞凋亡的影响及其机制。方法：以不同浓度 (0、20、40、80和160 μg/mL)GPS作用于人乳腺癌MCF-7细胞株48 h,以MTT法检测细胞增殖抑制情况,以GPS的最小有作用剂量与不同浓度 (0、0.5、1、2和4 μg/mL)TAM联合处理细胞48 h,以金氏公式筛选出协同抑制作用最明显的联合剂量,以该联合剂量处理MCF-7细胞48 h后,用DAPI染色法、流式细胞术检测细胞凋亡情况;用Giemsa染色检测细胞有丝分裂指数;用Western blot检测细胞中Fas、Caspase-9 以及Parp的表达情况。结果：MTT法检测提示GPS在48 h对MCF-7细胞的最小有作用剂量为40 μg/mL,金氏公式计算结果提示40 μg/mL GPS+1 μg/mL TAM联合用药协同抑制细胞增殖作用最强 (q=1.82);与GPS或TAM单独作用相比,DAPI染色发现联合用药组镜下可见大量凋亡小体;流式细胞仪检测发现,联合用药能够协同增加细胞凋亡率 ( q=2.19,P <0.05);Giemsa染色结果显示联合用药能够协同抑制细胞有丝分裂 (均P<0.05);Western blot检测发现,联合用药能增加细胞中Fas表达,促进Caspase-9以及Parp的活化。结论：GPS与TAM联合能够协同通过Fas信号通路促进人乳腺癌MCF-7细胞发生凋亡。