Calycosin induces apoptosis via p38-MAPK pathway-mediated activation of the mitochondrial apoptotic pathway in human osteosarcoma 143B cells
MOLECULAR MEDICINE REPORTS
Authors: Tian, Wei; Wang, Zhi-Wei; Yuan, Bao-Ming; Bao, Yong-Ge
Abstract
Previous studies have demonstrated that calycosin is a natural phytoestrogen with a similar structure to estrogen, which can inhibit cell proliferation and induce apoptosis in a variety of tumors. Calycosin exerts potential pharmacological effects on osteosarcoma cells by inducing apoptosis. The aim of the present study was to elucidate the specific molecular mechanism of calycosin-induced apoptosis in osteosarcoma cells. Cell proliferation was determined by an MTT assay. Annexin V/PI and JC-1 staining were used to detect apoptosis and mitochondrial dysfunction, respectively, by flow cytometry. Western blot analysis was used to detect the expression of caspases or mitochondrial proteins. The results revealed that calycosin reduced the cell viability of human osteosarcoma 143B cells, induced apoptosis and increased the loss of mitochondrial membrane potential (MMP). In addition, calycosin increased the expression of the proapoptotic antiapoptotic proteins cleaved caspase-3, cleaved caspase-9, cleaved poly(ADP-ribose) polymerase and Bcl-2-associated X protein (Bax), and decreased the expression of the antiapoptotic proapoptotic protein B-cell lymphoma-2 (Bcl-2), thus altering the Bax/Bcl-2 ratio. In addition, the expression levels of cytochromecwere markedly decreased in the mitochondria and increased in the cytoplasm following calycosin treatment. Furthermore, calycosin treatment induced p38-mitogen-activated protein kinase (MAPK) phosphorylation, whereas the p38-MAPK inhibitor BIRB 796 markedly reversed cell viability, apoptosis and loss of MMP in 143B cells. These results suggested that calycosin inhibited osteosarcoma 143B cell growth via p38-MAPK regulation of mitochondrial-dependent intrinsic apoptotic pathways.
Inhibition of autophagy enhances cadmium-induced apoptosis in duck renal tubular epithelial cells
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
Authors: Wang, Chang; Nie, Gaohui; Zhuang, Yu; Hu, Ruiming; Wu, Huansheng; Xing, Chenghong; Li, Guyue; Hu, Guoliang; Yang, Fan; Zhang, Caiying
Abstract
Increasing evidence indicates autophagy and apoptosis are involved in the toxicity mechanism of heavy metals. Our previous studies showed that cadmium (Cd) could induce autophagy and apoptosis in duck kidneys in vivo, nevertheless, the interaction between them has yet to be elucidated. Herein, the cells were either treated with 3CdSO(4)center dot 8H(2)O (0, 1.25, 2.5, 5.0 mu M Cd) or/and 3-methyladenine (3-MA) (2.5 mu M) for 12 h and the indictors related autophagy and apoptosis were detected to assess the correlation between autophagy and apoptosis induced by Cd in duck renal tubular epithelial cells. The results demonstrated that Cd exposure notably elevated intracellular and extracellular Cd contents, the number of autophagosomes and LC3 puncta, up-regulated LC3A, LC3B, Beclin-1, Atg5 mRNA levels, and Beclin-1 and LC3II/LC3I protein levels, down-regulated mTOR, p62 and Dynein mRNA levels and p62 protein level. Additionally, autophagy inhibitor 3-MA decreased Beclin-1, LC3II/LC3I protein levels and increased p62 protein level. Moreover, co-treatment with Cd and 3-MA could notably elevate Caspase-3, Cyt C, Bax, and Bak-1 mRNA levels, Caspase-3 and cleaved Caspase-3 protein levels, and cell apoptotic rate as well as cell damage, decreased mitochondrial membrane potential (MMP), Bcl-2 mRNA level and the ratio of Bcl-2 to Bax compared to treatment with Cd alone. Overall, these results indicate Cd exposure can induce autophagy in duck renal tubular epithelial cells, and inhibition of autophagy might aggravate Cd-induced apoptosis through mitochondria-mediated pathway.