ABSTRACT
Objective To investigate the effects of amyloid-β (Aβ)25-35 on endoplasmic reticulum (ER) stress and apoptosis in cultured rat cardiomocytes,and to elucidate the role of ER stress in the injury of cardiomocytes induced by Aβ25-35.Methods The isolated rat myocardial cells were cultured in vitro.Following stimulation of Aβ25-35 with different dose,the survival ratio was observed with methyl thiazolyl tetrazolium (MTT) method.Hoechst33258 staining was used to observe the morphology of apoptotic changes.The percentage of apoptotic cardiomyocytes was quantified with flow cytometry.The expressions of ER stree proteins,including X box-binding protein-1 (XBP-1),glucose-regulated protein 78 (GRP78),and CCAAT/enhancer-binding protein homologous protein (CHOP) were measured with Western blot.The cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) were measured with Western blot.Results Aβ25-35 decreased the survival ratio and induced the apoptosis of cultured rat cardiomocytes in dose-dependent mode.Meanwhile,Aβ25-35 increased the expressions of ER stree proteins,including XBP-1,GRP78,and CHOP.Aβ25-35 increased the expressions of cleaved caspase-3 and cleaved PARP.Conclusions Aβ25-35 could induce the apoptosis of rat cardiomyocytes,which were involved in ER stress possibly.This study might provide a new strategy for clinical treatment of Alzheimer's disease (AD)-associated myocardial injury.
ABSTRACT
Objective To explore effects of paclitaxel on proliferation and migration of breast cancer Michigan Cancer Foundation-7 (MCF-7) cells via mammalian target of rapamycin (mTOR) signaling pathway.Methods The cases were randomly divided into four groups,including control group,paclitaxel low-dose group (0.25 μmol/L),paclitaxel medium-dose group (0.5 μmol/L),and paclitaxel high-dose group (1 μmol/L).The viability of MCF-7 cells was measured with methyl thiazolyl tetrazolium (MTT) assay.MCF-7 cell cycle was examined with flow cytometry.MCF-7 cell migration was tested with transwell migration assay.The levels of mTOR signalling pathway-related protein were assayed with Western blot.Results Compared to the control group,MCF-7 cell viability was significantly decreased in paclitaxel low,medium and high-dose groups (P ＜ 0.05),and the inhibitory rate was highest at 48 h (P ＜ 0.05).MCF-7 cell migration was significantly inhibited in paclitaxel low,medium and high-dose groups [(98 ± 9.78) vs (86.21 ± 6.58),(53.41 ± 3.16) and (42.00 ± 4.69),P ＜ 0.05].Moreover,compared to the control group,the number of MCF-7 cells at G1 phase was significantly increased in paclitaxel low,medium and high-dose groups [(52.14±6.13)％ vs (67.93 ±8.16)％,(72.32 ±3.67)％ and (78.53 ± 6.28)％,P ＜ 0.01],the number of MCF-7 cells at G2 phase was significantly reduced in paclitaxel low,medium and high-dose group [(13.68 ± 0.85) ％ vs (8.57 ± 1.03) ％,(5.30 ± 0.89) ％ and (3.46 ± 0.78) ％,P ＜0.01].The phosphorylations of 4E binding protein (4EBP1) and mTOR proteins as well as the expressions of cell-cycle protein D1 (Cyclin D1) and matrix metalloproteinase-9 (MMP-9) were significantly inhibited in paclitaxel low,medium and high-dose groups (P ＜ 0.01).Conclusions These results suggested paclitaxel could inhibit proliferation and migration in breast cancer MCF-7 cells,which might be related to mTOR signal pathway.
