miR-340对乳腺癌MDA-MB231细胞增殖和凋亡的影响

背景与目的:既往研究表明,微小RNA-340(miR-340)能负性调控多种肿瘤的进展,但其在乳腺癌细胞增殖和凋亡中的研究较少,本研究旨在探讨miR-340对乳腺癌MDA-MB231细胞增殖和凋亡的作用。方法:利用脂质体LipofectamineTM2000将pre-miR-340或anti-miR-340瞬时转染至乳腺癌MDA-MB231细胞,通过RT-PCR检测miR-340 mRNA的水平,蛋白质印迹法(Western blot)检测cleaved-caspase-3蛋白的表达,MTT比色法检测细胞增殖的抑制情况,流式细胞仪检测细胞凋亡。结果:Pre-miR-340增加了MDA-MB231细胞中miR-340表达,同时增加cleaved-caspase-3蛋白表达、抑制MDA-MB231细胞增殖并促进其凋亡。而anti-miR-340抑制了MDAMB231细胞中miR-340表达,并且抑制cleaved-caspase-3蛋白表达,促进了MDA-MB231细胞增殖,抑制了MDAMB231细胞的凋亡。结论:miR-340转染后能上调MDA-MB231细胞中cleaved-caspase-3蛋白的表达从而抑制细胞增殖,促进其凋亡。

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

Effect of amlodipine on apoptosis of human breast carcinoma MDA-MB-231 cells

Objective： To elucidate the effects of amlodipine on the proliferation and apoptosis of human breast carcinoma MDA-MB-231 cells. Methods： Light microscopy was used to determine the effects of amlodipine on cell morphology; Flow cytometry was used to quantitate cells undergoing apoptosis; the expression of a cell cycle-related protein, proliferating cell nuclear antigen （PCNA） and an antiapoptosis protein, Bcl-2 were assessed by immunocytochemistry. Results： Amlodipine concentration of 8.25umol/L （1/2 of ICs0） affected the morphology, decreased the expression of PCNA and Bcl-2 and induced apoptosis of human breast carcinoma MDA-MB-231 cells. Conclusion： The effect of amlodipine on the antiproliferation of human breast carcinoma MDA-MB-231 cells is related to inducement of apoptosis, and the decrease of the expression of Bcl-2 and PCNA may be the possible mechanism for proliferation inhibitory and inducement of apoptosis.

uPAR expression under hypoxic conditions depends on iNOS modulated ERK phosphorylation in the MDA-MB-231 breast carcinoma cell line

Urokinase plasminogen activator receptor （uPAR） plays a major role in cancer-invasion and metastasis and uPAR expression is correlated with a poor prognosis in various cancer types. Moreover, the expression of uPAR is increased under hypoxic conditions. Nitric oxide （NO） and its metabolites produced by inducible nitric oxide synthase （iNOS） are important products ofhypoxic stress, and NO may activate or modulate extracellular signal regulated kinase （ERK）. Here, we evaluated uPA, uPAR, and activated ERK levels under hypoxic conditions, and the modulatory effects of iNOS and NO in the MDA-MB-231 human breast cancer cell line. Cells were incubated in a hypoxic or normoxic incubator and treated with PD98059 （a MEK 1/2 inhibitor, which abrogates ERK phosphorylation） and aminoguanidine （a selective iNOS inhibitor）, uPAR expression, ERK phosphorylation, and uPA activity were found to be increased under hypoxic conditions. Moreover, when cells were treated with PD98059 under hypoxic conditions, uPAR was downregulated, whereas aminoguanidine markedly increased ERK phosphorylation in a dose dependent manner. Furthermore, aminoguanidine increased uPAR expression and prevented the inhibition of uPAR expression by PD98059. These results demonstrated that uPAR is induced by hypoxia and that increased uPAR expression is mediated by ERK phosphorylation, which in turn is modulated by iNOS/NO in MDA-MB-231 cells. We conclude that iNOS/NO downregulates the expression of uPAR under hypoxic conditions via ERK pathway modulation.

杠柳毒苷体外抑制肝癌细胞和乳腺癌细胞增殖的实验研究

目的探讨杠柳毒苷在体外对人乳腺癌MDA-MB-468细胞和人肝癌HepG2细胞增殖的影响。方法 MTT法观察杠柳毒苷对人乳腺癌MDA-MB-468细胞和人肝癌HepG2细胞增殖的抑制作用,流式细胞术观察杠柳毒苷对两种肿瘤细胞的细胞增殖周期作用。结果与对照组比较,杠柳毒苷能明显抑制两种肿瘤细胞的增殖,其抑制率与药物浓度和作用时间呈正相关。流式细胞仪检测发现,杠柳毒苷对乳腺癌MDA-MB-468细胞和肝癌HepG2细胞持续作用24 h后,可以使G0/G1期细胞增多,G2/M期细胞减少。结论杠柳毒苷具有抑制乳腺癌MDA-MB-468细胞和肝癌HepG2细胞增殖的作用,并可将乳腺癌MDA-MB-468细胞和肝癌HepG2细胞的细胞生长周期阻滞在G0/G1期。