RANKL-induced migration of MDA-MB-231 human breast cancer cells via Src and MAPK activation

Accumulating studies have shown that the receptor activator of nuclear factor-κB ligand (RANKL)/RANK pathway plays an important role in tumor metastasis. However, the involvement of the RANKL/RANK signal transduction pathway in breast cancer metastasis remains unclear. The present study, therefore, investigated the role of downstream molecules of RANKL/RANK signaling in breast cancer cells using Transwell chemotaxis assays. RANKL was shown to direct the migration of MDA-MB-231 breast cancer cells. Osteoprotegerin (OPG; soluble decoy receptor of RANKL) inhibited RANKL-induced migration. RANKL activated Src kinase in MDA-MB-231 cells, as shown by Western blotting, and pretreatment with a Src inhibitor abrogated RANKL-induced cell migration, in a similar manner to OPG. Short-hairpin RNA against RANK, delivered via a lentiviral vector, significantly abolished the expression of phosphorylated Src. Stimulation by RANKL induced the phosphorylation of mitogen-activated protein kinases (MAPKs) (ERK, p38, JNK), and specific inhibitors of MAPKs blocked RANKL-induced cell migration. Furthermore, the expression of phosphorylated MAPKs could be blocked by a Src inhibitor and by small interfering RNA against Src. These findings suggest that Src and MAPK pathways may be involved in RANKL-induced MDA-MB-231 breast cancer cell migration.     

Complementary actions of docosahexaenoic acid and genistein on COX-2, PGE2 and invasiveness in MDA-MB-231 breast cancer cells

N-3 polyunsaturated fatty acids (PUFA) and genistein have been associated with lowered cancer risk by reducing inflammatory prostanoids, cyclooxygenase-2 (COX-2) activity, and altering cell signaling. Few studies have investigated the effect of these compounds in combination on the molecular control of the COX-2 gene. In a series of experiments we examined a potential synchronous action of n-3 PUFA and genistein in down-regulating COX-2 expression to diminish prostaglandin E(2) (PGE(2)) production in MDA-MB-231 human breast cancer cells. Cells were treated with genistein and various PUFA including arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). PGE(2) concentrations, expression of COX-2, and cell invasiveness were determined. The n-3 PUFA and genistein alone lowered PGE(2) concentration, and genistein in combination with AA reversed the high level of this prostanoid in cell cultures enriched with AA. The degree of cell invasiveness was reversed by genistein in cell cultures treated with AA and further reduced in those given DHA. The n-3 PUFA, in contrast to AA, reduced COX-2 and NFkappaB expression. Genistein combined with AA reversed the effects of AA alone on the expression of COX-2 and NFkappaB. All three fatty acids increased the expression of PPARgamma in the cells only when combined with genistein. Our results support the premise that DHA and genistein exert complementary actions whilst genistein is antagonistic to AA for controlling PGE(2) production as well as invasiveness of MDA-MB-231 cells in culture by modulating the level of NFkappaB expression.     

环加氧酶-2 通过调控EMT促进乳腺癌MDA-MB-231 细胞的迁移和侵袭

[摘要] 目的：探讨环加氧酶-2（COX-2）在乳腺癌转移中的作用及其可能的机制。方法：收集从2015 年10 月至2018 年4 月在云南省肿瘤医院接受乳腺切除术的患者中获得的原发乳腺癌组织和脑转移乳腺癌组织临床病理样本共45 例,其中原发30 例、脑转移15 例。采用qPCR检测COX-2 在原位乳腺癌和脑转移乳腺癌组织中的表达。将COX-2 过表达重组病毒（LV6-COX2）或敲减COX-2 重组病毒（LV3-COX2 shRNA1、LV3-COX2 shRNA2）感染人乳腺癌MDA-MB-231 细胞并获得稳转细胞株后,CCK-8法检测COX-2 表达对MDA-MB-231 细胞增殖的影响,划痕实验和Transwell 法检测对MDA-MB-231 细胞迁移和侵袭的影响。qPCR和WB实验分析各组细胞中COX-2 mRNA和蛋白的表达水平,qPCR检测COX-2 表达对MDA-MB-231 细胞内EMT相关基因表达的影响。结果：COX-2 表达水平在脑转移乳腺癌患者组织中显著高于原位乳腺癌组织（P<0.01）;并且与乳腺癌患者肿瘤TMN分期有关。成功构建稳定过表达/敲减COX-2 的MDA-MB-231 细胞株。过表达COX-2 促进MDA-MB-231 细胞的迁移和侵袭（均P<0.01）,同时显著提高MMP2、MMP1、N-cadherin 和vimentin 的表达（均P<0.01）,但对细胞增殖无明显影响;而沉默COX-2 则有相反的作用,且可促进细胞增殖（P<0.05）。结论：COX-2 在脑转移乳腺癌组织中高表达,其可能通过调控EMT过程促进乳腺癌MDA-MB-231 细胞的迁移和侵袭。     

桔梗皂苷D诱导乳腺癌MDA-MB-231细胞凋亡

目的:研究来自桔梗的天然单体化合物桔梗皂苷D(platycodin D,PD)对高转移性乳腺癌细胞MDA-MB-231凋亡的影响,初步探索其可能的作用机制.方法:以不同浓度(0、2.5、5、10 μmol/L)PD处理乳腺癌MDA-MB-231细胞后,采用MTT法检测细胞增殖率并计算IC50值,流式细胞术检测细胞凋亡情况,Western blotting检测凋亡相关蛋白的表达水平.结果:PD呈剂量依赖性显著抑制MDA-MB-231细胞的增殖(P＜0.01),作用72 h的IC50值为(7.30±2.67) μmol/L.与对照组相比,10 μmol/L的PD可显著促进MDA-MB-231细胞的凋亡(P＜0.05).PD激活了caspase家族蛋白,上调有活性的cleaved caspase-3、cleaved caspase-8和cleaved caspase-9的表达,下调无活性的caspase-8和caspase-9的表达;PD同时减少Bcl-2的表达,增加Bax的表达,使Bcl-2/Bax的比值降低.研究还发现PD使突变型P53蛋白的表达减少、E2F1的表达增加.结论:PD抑制乳腺癌细胞增殖具有明显的抗肿瘤效应,而诱导凋亡的发生可能是其发挥抗肿瘤效应的机制之一.     

Anti-Axl monoclonal antibodies attenuate the migration of MDA-MB-231 breast cancer cells

The receptor tyrosine kinase, anexelekto (Axl) is involved in tumor cell growth, migration and invasion, and has been associated with chemotherapy resistance, which makes it an attractive target for cancer therapy. In total, six Axl-targeted monoclonal antibodies (mAbs) and two antibody-drug conjugates have been reported in the last 10 years, which have been shown to have bioactivity in inhibiting tumor cell proliferation and migration. The Axl external cell domain (Axl^−ECD), consisting of 426 amino acids, has always been used as an antigen in the screening process for all six of these Axl-targeted mAbs. However, the Axl functional domain, which interacts with its natural ligand, growth arrest-specific protein 6 (Gas6), is only a small part of the Axl^−ECD. Antibodies targeting the Axl functional domain may efficiently block Gas6-Axl binding and attenuate its downstream signals and activities. To the best of our knowledge, no mAbs targeting the Axl functional domain have been reported. In the present study, a major Axl functional domain interacting with Gas6 was determined using bioinformatics and structural biology methods. In MDA-MB-231 breast cancer cell assays, anti-Axl mAbs targeting this relatively specific Axl functional domain almost completely neutralized the stimulation of Gas6 in both Axl phosphorylation and cell migration assays, and showed similar activity to the positive control drug R428 (a small molecular tyrosine kinase inhibitor of Axl currently in phase II clinical trials) in the cell migration assay. Given the important role of Axl in tumor development and chemotherapy resistance, Axl-targeted mAbs could be used to inhibit tumor cells directly, as well as reduce the development of chemotherapy resistance by blocking Axl activity. The application of Axl-targeted mAbs combined with chemotherapy provides a promising treatment strategy for patients with tumors, particularly those with triple-negative breast cancer, for whom no targeted therapy is currently available.     

In vitro effects of eicosanoid synthesis inhibitors in the presence of linoleic acid on MDA-MB-231 human breast cancer cells

We investigated the effects of cyclooxygenase and lipoxygenase inhibitors in the presence of linoleic acid (LA), as well as the direct effects of prostaglandin E (PGE) and leukotriene B (LTB) on a human breast cancer cell line (MDA-MB-231)in vitro. Piroxicam, esculetin, and nordihydroguaiaretic acid (NDGA) suppressed cell growth and thymidine incorporation. However, a low concentration (1 µg/ml) of indomethacin (INDO) stimulated cell growth and thymidine incorporation, while a high concentration of INDO (30 µg/ml) inhibited both. Esculetin and NDGA reduced the secretion of LTB, whereas piroxicam reduced the secretion of PGE. INDO reduced the secretion of PGE, but a low concentration of INDO increased the secretion of LTB. Consequently, cell growth was correlated with the PGE and/or LTB concentrations when the cells were treated with these cyclooxygenase or lipoxygenase inhibitors. On the other hand, exogenous PGE₂ partially reversed the inhibition of thymidine incorporation caused by INDO, whereas LTB₄ exerted a similar effect in the case of esculetin or NDGA. The reversibility of the piroxicam effect with PGE₂ is not convincing. Therefore, it is suggested that the growth of MDA-MB-231 cellsin vitro is affected by both the lipoxygenase and cyclooxygenase products, probably the other eicosanoids rather than PGE₂ and LTB₄.     

Conjugated linoleic acid induces apoptosis in MDA-MB-231 breast cancer cells through ERK/MAPK signalling and mitochondrial pathway

We investigated the molecular mechanisms involved in the anti-proliferative activity exerted by conjugated linoleic acid (CLA) on the estrogen unresponsive MDA-MB-231 human breast cancer cell line. The effects on cell proliferation, cell cycle progression and induction of apoptosis were examined. CLA caused the reduction of cell proliferation along with the accumulation of cells in the S phase of the cycle. The occurrence of apoptosis in these cells was indicated by flow cytometry data and further confirmed by the onset of cells with morphological features typical of apoptosis. ERK1/2 reduction and upregulation of pro-apoptotic protein Bak were induced. These events were associated with: (a) reduced levels of the anti-apoptotic protein Bcl-x(L), (b) the translocation of cytochrome c from the mitochondria to the cytosol, (c) the cleavage of pro-caspase-9 and pro-caspase-3. From the above data, we are induced to think that CLA may trigger apoptosis in the estrogen unresponsive MDA-MB-231 cell line via mechanisms involving above all the mitochondrial pathway.     

金雀异黄素诱导乳腺癌MDA-MB-231细胞凋亡的研究

目的 探讨金雀异黄素（genistein,GEN）诱导乳腺癌MDA-MB-231细胞凋亡的分子机制.方法 用0、5、10、20 μmol/L GEN处理MDA-MB-231 细胞24 h.采用CCK-8、Hoechst 33342染色和流式细胞仪测定不同浓度GEN对 MDA-MB-231细胞增殖和凋亡的影响.采用Western blotting检测不同浓度GEN处理前后MDA-MB-231细胞中Fas相关死亡域蛋白（FADD）、活性半胱天冬酶8（cleaved caspase-8）、Fas、FasL蛋白表达水平.采用实时RT-PCR分析不同浓度GEN处理前后MDA-MB-231细胞中Fas、FasL基因表达水平.多组均数比较采用方差齐性检验后进行单因素方差分析.结果 在GEN作用24 h后,0、5、10和20 μmol/L组对MDA-MB-231细胞增殖的抑制率分别为（3.00±1.41）%、（14.02±1.57）%、（27.5±1.52）%、（48.90±1.44）%.与0 μmol/L组相比,5、10和20 μmol/L组呈浓度依赖性增加（F=528.119,P=0.000）.两两比较显示：各浓度组之间差异均有统计学意义（P〈0.05）.0、5、10和20 μmol/L组诱导MDA-MB-231细胞的早期凋亡率分别为（3.40±0.40）%、（9.34±1.34）%、（19.26±0.93）%、（27.41±1.12）%.与0 μmol/L组相比,5、10和20 μmol/L组呈浓度依赖性增加（F=379.573,P=0.000）.两两比较显示：各浓度组之间差异均有统计学意义（P〈0.05）.Western blotting结果显示,与0 μmol/L组相比,其他浓度组经GEN处理的MDA-MB-231细胞FADD、cleaved caspase-8、FasL蛋白表达升高（F=368.621、456.744、419.129,P均=0.000）,Fas蛋白表达差异无统计学意义（F=0.800,P=0.528）;与10（μmol/L组相比,20 μmol/L组FasL蛋白表达降低有统计学意义（F=92.235,P=0.001）.实时RT-PCR结果显示,与0 μmol/L组相比,其他浓度组经GEN处理的MDA-MB-231细胞FasL mRNA表达升高（F=646.983,P=0.000）,Fas mRNA表达差异无统计学意义（F=1.556,P=0.274）;与10 μmol/L组相比,20 μmol/L组FasL mRNA表达降低有统计学意义（F=52.562,P=0.020）.结论 GEN通过上调Fas/FasL途径中FasL基因表达诱导乳腺癌MDA-MB-231细胞凋亡.     

c-Met蛋白在CCL5诱导的乳腺癌MDA-MB-231细胞迁移中的作用

目的:探讨c-Met蛋白在CC型趋化因子5(CCL5)诱导的乳腺癌MDA-MB-231细胞迁移中的作用.方法:Western-Blot检测乳腺癌MDA-MB-231细胞表面CCL5受体(CCR5)的表达情况;Transwell法检测CCL5诱导的MDA-MB-231细胞迁移能力的变化;Western-Blot检测CCL5刺激后MDA-MB-231细胞c-Met及磷酸化c-Met(p-Met)的表达.结果:乳腺癌MDA-MB-231细胞表面高表达CCR5蛋白;CCL5增强MDA-MB-231细胞的迁移能力,沉默CCR5基因后抑制了CCR5蛋白表达,MDA-MB-231细胞迁移能力降低;MDA-MB-231细胞表达的p-Met水平在CCL5刺激10 min后明显升高.结论:CCL5/CCR5信号通路可以促进乳腺癌MDA-MB-231细胞的迁移能力,c-Met蛋白参与CCL5诱导的乳腺癌MDA-MB-231细胞迁移.     

胰岛素样生长因子1型受体短发夹RNA抑制乳腺癌增殖和迁移能力的体外实验研究

目的 应用短发夹RNA（short hairpin RNA,shRNA）抑制乳腺癌MDA—MB-231细胞胰岛素样生长因子1型受体（type I insulin—like growth factor receptor,IGF-1R）的表达,探讨IGF～1R对乳腺癌体外增殖和迁移的作用。方法构建携带有绿色荧光蛋白报告基因的IGF-1R shRNA质粒载体,脂质体介导转染MDAMB-231细胞,通过倒置荧光显微镜检测转染效率,CCK-8法检测细胞增殖能力,体外迁移实验检测细胞迁移能力。细胞增殖实验结果的组间比较采用重复测量方差分析和多元方差分析,RT—PCR定量结果和迁移实验结果的组间比较采用单因素方差分析。结果成功构建IGF-1RshRNA质粒载体,转染效率为55％～60％。IGF-1R shRNA转染MDA—MB-231细胞后,MDA—MB-231细胞IGF-1R mRNA与蛋白表达水平显著下降;细胞体外增殖和迁移能力受到显著抑制（P均〈O．05）。结论IGF-1R shRNA表达质粒可以有效抑制MDA—MB-231细胞IGF-1R的表达,显著抑制乳腺癌细胞的体外增殖和迁移能力。     

Up-regulation of LOX-1 expression by TNF-alpha promotes trans-endothelial migration of MDA-MB-231 breast cancer cells

Adhesion of cancer cell to endothelial cells and the subsequent trans-endothelial migration are key steps in metastasis. However, the identities of the molecules mediating cancer cell/endothelial cell interaction are still not fully understood. In this study, we tested the hypothesis that lectin-like oxidized-low-density lipoprotein (oxLDL) receptor-1 (LOX-1), a key mediator of vascular inflammation and atherosclerosis expressed on endothelial cell surface, mediates breast cancer cell/endothelial cell interactions. We showed that up-regulation of endothelial LOX-1 by TNF-alpha promoted the adhesion and trans-endothelial migration of MDA-MB-231 breast cancer cells. Thus, endothelial LOX-1 could present a novel pathway in breast cancer metastasis.     

Flavonoid baicalein suppresses adhesion,migration and invasion of MDA-MB-231 human breast cancer cells

Baicalein is a widely used Chinese herbal medicine that has been used historically in anti-inflammatory and anti-cancer therapy. However, the molecular mechanism of its anti-cancer activity remains poorly understood and warrants further investigations. The purpose of this study is to verify the activity of baicalein to inhibit the invasion of MDA-MB-231 human breast cancer cells. The results indicated that baicalein suppressed MDA-MB-231 cell adhesion to fibronectin-coated substrate, wound healing migration and invasion through the Matrigel in a concentration-dependent manner. Western blot and gelatin zymography analysis showed that baicalein significantly inhibited the expression and secretion of matrix metalloproteinases 2/9 (MMP-2/9) in MDA-MB-231 cells. Additionally, treatment of MDA-MB-231 cells with baicalein down-regulated the expression of MMP-2/9 involved mitogen-activated protein kinases (MAPK) signaling pathway. Taken together, baicalein had potential to suppress the adhesion, migration and invasion of MDA-MB-231 cancer cells in vitro and it could serve as a promising drug for the treatment of cancer metastasis.     

Enhanced retinoid-induced apoptosis of MDA-MB-231 breast cancer cells by PKC inhibitors involves activation of ERK

Retinoids are vitamin A derivatives, which cause growth inhibition, differentiation and/or apoptosis in various cell types, including some breast cancer cells. In general, estrogen receptor (ER)-positive cells are retinoic acid (RA) sensitive, whereas ER-negative cells are resistant. In this report, we show that ER-negative MDA-MB-231 cells are strongly growth inhibited by retinoids in combination with a PKC inhibitor. While neither RA nor GF109203X (GF) has a significant growth inhibitory effect in these cells, RA+GF potently suppress proliferation. We found that RA+GF induce apoptosis, as shown by an increase in fragmented DNA, Annexin-V-positive cells and caspase-3 activation. Apoptosis was also induced by GF in combination with two synthetic retinoids. Expression of phosphorylated as well as total PKC was decreased by GF and this was potentiated by RA. In addition, treatment with GF caused a strong and sustained activation of ERK1/2 and p38-MAPK, as well as a weaker activation of JNK. Importantly, inhibition of ERK but not p38 or JNK suppressed apoptosis induced by RA+GF, indicating that activation of ERK is specifically required. In support of this novel finding, the ability of other PKC inhibitors to cause apoptosis in combination with RA correlates with ability to cause sustained activation of ERK.     

Hypoxia regulates stemness of breast cancer MDA-MB-231 cells

Human breast cancers include cancer stem cell populations as well as non-tumorigenic cancer cells. Breast cancer stem cells possess self-renewal capability and thus are the root cause of recurrence and metastasis of malignant tumors. Hypoxia is a fundamental pathological feature of solid tumor tissues and exerts a wide range of effects on the biological behavior of cancer cells. However, there is little information on the role of hypoxia in modulating the stemness of breast cancer cells. In the present study, we cultured MDA-MB-231 cells in a hypoxic gas mixture to simulate the hypoxic environment in tissues and to determine how hypoxia conditions could affect the cell proliferation, apoptosis, cytotoxicity, and colony-forming ability. Expression of the stem cell phenotype CD24^?CD44⁺ESA⁺ was analyzed to assess the effects of hypoxia on stemness transformation in MDA-MB-231 cells. Our results found that the cell toxicity of MDA-MB-231 cells was not affected by hypoxia. Hypoxia could slightly inhibit the growth of MDA-MB-231 cells, but the inhibitory effect is not significant when compared with normoxic control. Moreover, hypoxia significantly blocked the apoptosis in MDA-MB-231 cells (P < 0.05). The proportion of CD24^?CD44⁺ESA⁺ cells in MDA-MB-231 cells was increased greatly after they were treated with hypoxia, and cell colony-formation rate of MDA-MB-231 cells also increased significantly in hypoxia-treated cells. These results encourage the exploration of hypoxia as a mechanism which might not be underestimated in chemo-resistant breast cancer treatment.     

Radiation-enhancement of MDA-MB-231 breast cancer cell invasion prevented by a cyclooxygenase-2 inhibitor

Background:

Recent evidences support that radiation can promote the invasion of cancer cells. As interactions between cancer cells and surrounding stromal cells can have an important role in tumour progression, we determined whether an irradiation to fibroblasts can enhance the invasiveness of breast cancer cells. The role of cyclooxygenase-2 (COX-2), an inflammatory enzyme frequently induced by radiotherapy, was investigated.

Methods:

Irradiated 3T3 fibroblasts were plated in the lower compartment of invasion chambers and used as chemoattractant for non-irradiated human breast cancer cell MDA-MB-231, which are oestrogen receptor negative (ER(−)) and the oestrogen receptor positive (ER(+)) MCF-7 cells. Stimulation of COX-2 expression in irradiated 3T3 cells was measured by a semi-quantitative qPCR and western blot. Capacity of the major product of COX-2, the prostaglandin E2 (PGE₂), to stimulate the production of the matrix metalloproteinase-2 (MMP-2) and cancer cell invasion were assessed with a zymography gel and invasion chambers.

Results:

Irradiation (5 Gy) of 3T3 fibroblasts increased COX-2 expression and enhanced by 5.8-fold the invasiveness of non-irradiated MDA-MB-231 cells, while their migration was not modified. Addition of the COX-2 inhibitor NS-398 completely prevented radiation-enhancement of cancer cell invasion. Further supporting the potential role of COX-2, addition of PGE₂ has increased cancer cell invasion and release of MMP-2 from the MDA-MB-231 cells. This effect of radiation was dependant on the expression of membrane type 1 (MT1)–MMP, which is required to activate the MMP-2, but was not associated with the ER status. Although irradiated fibroblasts stimulated the invasiveness of MDA-MB-231 ER(−) cells, no enhancement was measured with the ER(+) cell line MCF-7.

Conclusions:

Radiation-enhancement of breast cancer cell invasion induced by irradiated 3T3 fibroblasts is not dependant on the ER status, but rather the expression of MT1–MMP. This adverse effect of radiation can be prevented by a specific COX-2 inhibitor.     

乏氧环境下HO-1诱导表达对乳腺癌MDA-MB-231细胞侵袭迁移的调控作用研究

目的:研究乏氧对人乳腺癌MDA-MB-231细胞侵袭及迁移能力的影响,并研究血红素氧合酶-1(heme oxygenase-1,HO-1)在这一过程中的作用,初步探讨其作用机制。方法:利用RNA干扰技术,抑制乳腺癌MDA-MB-231细胞中HO-1的表达,得到HO-1表达受干扰的细胞系MDA-MB-231-HO-1△。通过Transwell迁移、侵袭实验分别检测常氧及乏氧条件下MDA-MB-231-NC细胞（HO-1正常表达）和MDA-MB-231-HO-1△细胞（HO-1干扰表达）迁移、侵袭能力的变化,Western blot检测乏氧条件下两组乳腺癌细胞的上皮和间质标记物的表达,检验细胞系是否发生了上皮-间质转化(epithelial-mesenchymal transition,EMT)。结果:乏氧培养24小时后,MDA-MB-231-NC 细胞中HO-1蛋白表达水平显著升高,MDA-MB-231-HO-1△细胞中HO-1表达受抑制。乏氧培养后MDA-MB-231-NC细胞的侵袭、迁移能力较常氧培养的细胞明显增强,其差异具有统计学意义(P<0.05);而MDA-MB-231-HO-1△细胞侵袭、迁移能力在乏氧和常氧培养下无显著差异。乏氧条件下,MDA-MB-231-NC细胞的上皮标志物E-cadherin表达显著下调,间质标志物Vimentin表达显著上调,而MDA-MB-231-HO-1△细胞的E-cadherin、Vimentin表达无明显变化。结论:乏氧条件下乳腺癌MDA-MB-231细胞中HO-1可被诱导高表达,促进了细胞的侵袭迁移,其可能机制是促进了乳腺癌细胞上皮-间质转化。     

干扰LOX表达对MDA-MB-231细胞侵袭迁移影响及其机制的探讨

目的:研究干扰赖氨酰氧化酶(LOX)基因表达对乳腺癌细胞MDA-MB-231体外侵袭迁移能力的影响,并探讨相关机制及意义。方法:设计合成特异性慢病毒干扰载体(LOX-RNAi-LV)转染MDA-MB-231细胞,实时定量PCR检测LOX mRNA和侵袭转移相关因子MMP-2、MMP-9和HIF-1α的mRNA表达,蛋白质印迹法检测LOX蛋白表达,细胞侵袭迁移实验(Transwell)检测细胞侵袭迁移能力。结果:转染LOX-RNAi-LV后,乳腺癌MDA-MB-231细胞LOXmRNA和蛋白表达水平明显降低,与空白组相比,抑制率分别为89.2%和82.97%。MMP-2(F=225.271,P=0.0000)、MMP-9(F=35.373,P=0.000 01)和低氧诱导因子HIF-1α(F=341.081,P=0.0000)的mRNA表达均明显降低。细胞侵袭迁移实验显示,干扰组穿过Transwell小室滤过膜的细胞数明显少于对照组(侵袭实验F=269.557,P=0.000 5;迁移实验F=164.321,P=0.000 3)。结论:转染LOX-RNAi-LV能有效地干扰LOX在乳腺癌细胞MDA-MB-231中表达,抑制肿瘤细胞的侵袭和迁移能力,其作用机制可能与下调MMP-2、MMP-9和HIF-1α表达有关。     

Induction of apoptosis in breast cancer cells MDA-MB-231 by genistein.

Breast cancer is the most common cancer among American women, whereas Asian women, who consume a traditional diet high in soy products, have a relatively low incidence. Genistein is a prominent isoflavonoid in soy products and has been proposed as the agent responsible for lowering the rate of breast cancer in Asian women. We investigated the effects of genistein on cell growth and apoptosis-related gene expression in breast cancer cells MDA-MB-231. We found up-regulation of Bax and p21WAF1 expressions and down-regulation of Bcl-2 and p53 expression in genistein-treated cells. Furthermore, DNA ladder formation, CPP32 activation, and PARP cleavage were observed after treatment with genistein, indicating apoptotic cell deaths. Flow cytometry with 7-amino actinomycin D staining showed that the number of apoptotic cells increased with longer treatment of genistein. From these results, we conclude that genistein inhibits the growth of MDA-MB-231 breast cancer cells, regulates the expression of apoptosis-related genes, and induces apoptosis through a p53-independent pathway. The up-regulation of Bax and p21WAF1 may be the molecular mechanisms by which genistein induces apoptosis, however, further definitive studies are needed. These results suggest that genistein may be a potentially effective chemopreventive or therapeutic agent against breast cancer.     

AZD2281诱导乳腺癌MDA-MB-231细胞凋亡的实验研究

目的 观察AZD2281对乳腺癌MDA-MB-231细胞株增殖和凋亡的影响,并探讨其可能的机制。方法MTT法和流式细胞仪法观察不同浓度AZD2281（2.5、5、10 nmol/L）作用于MDA-MB-231细胞24、48、72 h后对细胞增殖、周期分布及细胞凋亡的影响;Western blotting检测经AZD2281处理该细胞24 h后细胞凋亡相关蛋白Bcl-2和caspase-3表达水平的变化。结果AZD2281可显著抑制MDA-MB-231细胞增殖,且呈时间和剂量依赖性;AZD2281作用于MDA-MB-231细胞24 h后,细胞被阻滞在G0/G1期,并促进其凋亡,且呈剂量依赖性。AZD2281作用MDA-MB-231细胞24 h后,凋亡抑制蛋白Bcl-2的表达呈剂量依赖性下降,而凋亡促进蛋白caspase-3的表达呈剂量依赖性上升。结论AZD2281能显著抑制MDA-MB-231细胞增殖和促进其凋亡,其作用机制可能是通过上调caspase-3和下调Bcl-2蛋白表达实现的。