Experimental study and clinical significance of AR/let-7 signaling pathway in inhibiting the proliferation of triple negative breast cancer / 中华内分泌外科杂志

Objective To investigate the mechanism of AR/let-7 signaling pathway in inhibiting the proliferation of TNBC and its significance for survival.Methods Human breast cancer MDA-MB-453 cells were cultured in vitro and divided into experimental group and control group.The experimental group was added with androgen dihydrotestosterone(DHT),and the control group was added nothing.The cell proliferation was detected by CCK-8,cell cycle was detected by flow cytometry,AR expression was detected by Western blot,and let-7 expression was detected by real-time fluorescent quantitative PCR.The AR,let-7 expression data and survival data of TNBC patients were downloaded from the Cancer Genomes Atlas (TCGA).The expression of AR and let-7 between cancer tissues and normal breast tissues and their relationship with survival was analyzed.Results Cellular experiments showed that the proliferation rate of cancer cells in the experimental group was significantly lower than that in the control group(1.22±0.11 vs 2.26±0.23,t=7.065,P＜0.05),and the ratio of G1/S in the experimental group was greater than in the control group (1.08±0.03 vs 0.68±0.03,t=17.321,P=0.000).The AR and let-7a,b,c,and d were overexpressed in the experimental group.The TCGA data showed that AR,let-7a-1,let-7a-2,let7a-3,and let-7c were lower in breast cancer tissues than in normal tissues (P＜0.05),while let-7d was higher in breast cancer tissues (P＜0.05).The AR,let-7a-1,let-7a-2,let-7a-3,and let-7c were used to cluster the patients into high-expression group and low-expression group,and the overall survival in the high-expression group appeared to be higher,while the difference was not statistically significant (P=0.163).Conclusions The AR/let-7 signaling pathway is up-regulated by DHT activation,which blocks cells in the G1 phase and inhibits cell proliferation.Patients with high expression of AR,let-7a-1,let-7a-2,let-7a-3,and let-7c may have better overall survival.It is suggests that the AR/let-7 signaling pathway may become a new target for TNBC.

Apoptotic effects of polyporusterone A on estrogen receptor negative breast cancer cells via regulating Bcl-2/Bax pathway / 中草药

Objective To explore the apoptotic effect of polyporusterone A on estrogen receptor (ER)-positive and ER-negative human breast cancer cells and the possible mechanism. Methods Three human breast cancer cell lines (MDA-MB-453, MCF-7, and BT474) were chosen in this study. MTT assay was performed to measure the relative cell viabilities. Flow cytometry was used to analyze the apoptosis and cell cycle. Western blot analysis was used to determine the expression levels of Bcl-2 family proteins. Results Cell proliferation of ER-negative human breast cancer cells was significantly inhibited by polyporusterone A in a dose-and time-dependent manner, while no significant effect was observed on the proliferation of strogen receptor (ER)-positive human breast cancer MCF-7 and BT474 cells. Moreover, polyporusterone A could reversibly arrest the MDA-MB-253 cells in G1 or G2/M phase. Flow cytometry results showed that 50 μmol/L polyporusterone A induced MDA-MB-253 cells apoptosis after treatment for 24 h, while no apoptosis occurred in MCF-7 and BT474 cell lines. Western blot results showed that 50 μmol/L polyporusterone A up-regulated the protein expression of Bad and Bax, but down-regulated the expression of Bcl-2 and Bcl-w protein. Conclusion Polyporusterone A can inhibit the proliferation of ER-negative breast cancer cells and promote apoptosis, which may be associated with the regulation of the expression of Bcl-2 family proteins.

Kaempferol induced the apoptosis via cell cycle arrest in human breast cancer MDA-MB-453 cells

The aim of present study was to investigate the effects of kaempferol on cellular proliferation and cell cycle arrest and explore the mechanism for these effects in human breast carcinoma MDA-MB-453 cells. Cells were treated with kaempferol at various concentrations (ranging from 1 to 200 microM) for 24 and 48 hrs. Kaempferol significantly inhibited cancer cell growth in cells exposed to 50 and 10 microM of kaempferol and incubated for 24 and 48 hrs, respectively. Exposure to kaempferol resulted in cell cycle arrest at the G2/M phase. Of the G2/M-phase related proteins, kaempferol down-regulated CDK1 and cyclin A and B in cells exposed to kaempferol. In addition, small DNA fragments at the sub-G0 phase were increased by up to 23.12 and 31.90% at 10 and 50 microM incubated for 24 and 48 hrs, respectively. The kaempferol-induced apoptosis was associated with the up-regulation of p53. In addition, the phosphorylation of p53 at the Ser-15 residue was observed with kaempferol. Kaempferol inhibits cell proliferation by disrupting the cell cycle, which is strongly associated with the induction of arrest at G2/M phase and may induce apoptosis via p53 phosphorylation in human breast carcinoma MDA-MB-453 cells.

STUDY ON THE MECHANISMS OF GENISTEIN AFFECTING THE CHEMOSENSITIVITY OF HUMAN BREAST CANCER CELL LINE MDA-MB-453 TO PACLITAXEL IN VITRO / 营养学报

Objective:To investigate the mechanisms of genistein (GEN) affecting the chemosen- sitivity of human breast cancer cell line MDA-MB-453 to paclitaxel (PTX) in vitro. Method:HER2/neu- overexpressing breast cancer cells MDA-MB-453 were treated by GEN, PTX alone or combined in vitro. Cell cycle was measured by flow cytometry. The expression of HER2/neu protein was observed by immunocytochemistry and. Akt, p-Akt, cyclin B1 and CDK1 protein by Western blot. Results:Cell cycle of MDA-MB-453 cells was blocked at G1/S after treatment of GEN, while at G2/M after treatment with PTX alone. Both GEN and PTX did not change the expression of HER2/neu, total Akt and CDK1 in MDA-MB-453 cells, but GEN significantly decreased p-Akt and cyclin B1 level, and PTX obviously increased cyclinB1 level. GEN antagonized the effects of PTX on level of cyclin B1 protein and blockage of G2/M in MDA-MB-453 cells after treatment with GEN and PTX in combination. Conclusion:The antagonism effects of GEN on the increase of cyclin B1 and blockage of G2/M induced by PTX may be one of the mechanisms of GEN affecting the chemosensitivity of MDA-MB-453 cells to PYX.

Synergistic effects of Herceptin and 9-cis-RA on MDA-MB-453 breast cancer cells / 第三军医大学学报

Objective To investigate the synergistic effects of Herceptin and 9-cis-RA on the proliferation, cell cycle and apoptosis of HER2-positive breast cancer cells. Methods MDA-MB-453 breast cancer cells were treated with 5 ?g/ml Herceptin or 1 ?mol/L 9-cis-RA or both for 24, 48 or 72 h. The proliferation of MDA-MB-453 breast cancer cells was determined by MTT, the pro-apoptotic effects were detected by TUNEL, the cell cycle phase was detected by FCM. Results As compared with control group, Herceptin and 9-cis-RA synergistically inhibited the proliferation of MDA-MB-453 breast cancer cells, and the percentage of G_ 0 /G_ 1 cells increased after treatment with Herceptin and 9-cis-RA for 72 h. Simultaneously, Herceptin and 9-cis-RA synergistically induced the apoptosis of MDA-MB-453 cells. Conclusion Herceptin and 9-cis-RA could synergistically and effectively inhibit MDA-MB-453 breast cancer cells by blocking their cell cycle progression and inducing their apoptosis.

EFFECT OF GENISTEIN ON THE EXPRESSION OF UPA AND THE ACTIVITY OF PTK IN MDA-MB-453 BREAST CANCER CELLS / 营养学报

Objective: To study the effects of genistein on the expression of urokinase-type plasminogen activator (uPA) and the activity of protein tyrosine kinase (PTK) in MDA-MB-453 cells, and explore the molecular mechanism of anti-angiogenesis in HER-2/neu-overexpressing breast cancer by genistein. Methods:Western blot, immunoprecipitate, reverse transcription-polymerase chain reaction (RT-PCR) and kinase activity analysis technics were used to observe the expression of uPA and the protein phosphorylation of HER-2/neu receptor and the activity of protein tyrosine kinase (PTK) in MDA-MB-453 cells treated by genistein for 24, 48, 72 h. Results: The expression of uPA and the protein phosphorylation of HER-2/neu receptor and the activity of PTK were significantly decreased after treated with 5?10-5mol/L genistein, which had a time-dependence. Conclusion: Genistein could inhibit the activity of PTK and the protein phosphorylation of HER-2/neu receptor, and down-regulate the exprssion of uPA at transcription and translation levels in breast cancer cells. This might be a part of molecular mechanism of genistein anti-angiogenesis in HER-2/neu-overexpressing breast cancer.