ABSTRACT
The aim of this study was to investigate the effects of AEG-1 gene silencing on the chemoresistance of human breast cancer cell line MCF-7/ADM and its possible mechanism. MCF-7/ADM cells were incubated in the medium containing adriamycin (ADM). The recombinant pLKO.1-shAEG-1 plasmid was constructed to silence AEG-1 expression in human breast cancer MCF-7/ADM cells. MTT assay was employed to detect the anti-tumor effect of ADM on MCF-7/ADM cells, and IC50 value of ADM was calculated according to MTT. Flow cytometry was used to determine the apoptosis. Western blot was used to analyze the expression levels of AEG-1, p-Akt, p-MDM2, p-Bad, p53 and MDR1. The result showed MCF-7/ADM had a significantly higher expression level of AEG-1 compared with that of MCF-7 (P < 0.05), however, the expression of AEG-1 was decreased after AEG-1 gene silencing. The IC50 value of ADM in shAEG-1 group was significantly lower than that in shcontrol group. AEG-1 gene silencing induced cell apoptosis and enhanced the pro-apoptotic effect of ADM on MCF-7/ADM cells. After AEG-1 gene silencing, the phosphorylation of Akt, MDM2 and Bad was inhibited (P < 0.05), the protein levels of p53 and MDR1 were up-regulated (P < 0.05) and down-regulated (P < 0.05) respectively, compared with control. In conclusion, the results suggest that AEG-1 gene silencing can reverse the ADM resistance in human breast cancer cell line MCF-7/ADM by means of inducing apoptosis and down-regulating the protein level of MDR1.
Subject(s)
Humans , Apoptosis , Breast Neoplasms , Genetics , Metabolism , Cell Adhesion Molecules , Genetics , Metabolism , Doxorubicin , Pharmacology , Drug Resistance, Neoplasm , Genetics , Gene Silencing , MCF-7 CellsABSTRACT
The present study was to investigate the effects of exogenous insulin-like growth factor binding protein 7 (IGFBP7) on the proliferation of human breast cancer cell line MDA-MB-453 and its possible mechanism. By means of MTT method in vitro, the results showed exogenous IGFBP7 inhibited the growth of MDA-MB-453 cells (IC50 of IGFBP7 = 8.49 μg/mL) in time- and concentration-dependent manner. SB203580, p38(MAPK) inhibitor, blocked the anti-proliferative effect of exogenous IGFBP7. The flow cytometry assay showed that exogenous IGFBP7 remarkably induced G0/G1 arrest in MDA-MB-453 cells. The Western blot showed that exogenous IGFBP7 promoted phosphorylation of p38(MAPK), up-regulated expression of p21(CIP1/WAF1), and inhibited phosphorylation of Rb. SB203580 restrained exogenous IGFBP7-induced regulation of p21(CIP1/WAF1) and p-Rb in MDA-MB-453 cells. In conclusion, the present study suggests that exogenous IGFBP7 could activate the p38(MAPK) signaling pathway, upregulate p21(CIP1/WAF1) expression, inhibit phosphorylation of Rb, and finally induce G0/G1 arrest in MDA-MB-453 cells.
Subject(s)
Female , Humans , Breast Neoplasms , Pathology , Cell Line, Tumor , Cell Proliferation , Cyclin-Dependent Kinase Inhibitor p21 , Metabolism , Imidazoles , Pharmacology , Insulin-Like Growth Factor Binding Proteins , Pharmacology , Phosphorylation , Pyridines , Pharmacology , Signal Transduction , Somatomedins , p38 Mitogen-Activated Protein Kinases , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To study the pathologic changes of the palatopharyngeal muscles in patients with obstructive sleep apnea hypopnea syndrome (OSAHS), the role of the above muscles in OSAHS pathogenesis was discussed.</p><p><b>METHODS</b>Thirty OSAHS patients receiving uvulopalatopharyngoplasty selected, and ten normal subjects without snoring as the control group. The successive longitudinal sections of palatopharyngeal muscle were stained for observing Troponin-I's content. All specimens were examined with transmission electronmicroscopy (TEM) and light microscopy.</p><p><b>RESULTS</b>Twenty nine of 30 specimens obtained from OSAHS patients evaluated with TEM showed pathologic changes of different degrees. While 2 among 10 specimens in control group showed mild myofibril edema or hypertrophy, no pathologic changes shown in other specimens. Immunohistochemistrial results of all specimens sections stained for observing Troponin-I antibody have shown that negative grey degree value is 146.30 +/- 10.72 in study group and 107.50 +/- 4.81 in control group respectively. There is significant difference between these two groups (P < 0.05). The negative grey degree value of study groupl and study group2 are 143.12 and 148.80 respectively , no statistical difference (P > 0.05).</p><p><b>CONCLUSIONS</b>Palatopharyngeal myelofibrosis may affect pharyngeal dilator muscles function, this could be one mechanism of upper airway collapsibility.</p>