Co-reporter:Feng Hao;Jinsen Kang;Yajun Cao;Shengjun Fan;Haopeng Yang;Yu An;Yan Pan
Apoptosis 2015 Volume 20( Issue 11) pp:1420-1432
Publication Date(Web):2015 November
DOI:10.1007/s10495-015-1150-0
Lipotoxicity plays a vital role in development and progression of type 2 diabetes. Prolonged elevation of free fatty acids especially the palmitate leads to pancreatic β-cell dysfunction and apoptosis. Curcumin (diferuloylmethane), a polyphenol from the curry spice turmeric, is considered to be a broadly cytoprotective agent. The present study was designed to determine the protective effect of curcumin on palmitate-induced apoptosis in β-cells and investigate underlying mechanisms. Our results showed that curcumin improved cell viability and enhanced glucose-induced insulin secretory function in MIN6 pancreatic β-cells. Palmitate incubation evoked chromatin condensation, DNA nick end labeling and activation of caspase-3 and -9. Curcumin treatment inhibited palmitate-induced apoptosis, relieved mitochondrial depolarization and up-regulated Bcl-2/Bax ratio. Palmitate induced the generation of reactive oxygen species and inhibited activities of antioxidant enzymes, which could be neutralized by curcumin treatment. Moreover, curcumin could promote rapid phosphorylation of Akt and nuclear exclusion of FoxO1 in MIN6 cells under lipotoxic condition. Phosphatidylinositol 3-kinase and Akt specific inhibitors abolished the anti-lipotoxic effect of curcumin and stimulated FoxO1 nuclear translocation. These findings suggested that curcumin protected MIN6 pancreatic β-Cells against apoptosis through activation of Akt, inhibition of nuclear translocation of FoxO1 and mitochondrial survival pathway.
Co-reporter:Min Gao;Hong Zhou ;Xuejun Li
Basic & Clinical Pharmacology & Toxicology 2009 Volume 104( Issue 3) pp:236-240
Publication Date(Web):
DOI:10.1111/j.1742-7843.2008.00369.x
Abstract: Antiglucocorticoid therapy in depressed patients is effective, which indicates that glucocorticoids play a key role in the occurrence of depression. Our previous work demonstrated the efficacy of curcumin in treating depression in rat and mouse models. We characterized the protective effects of curcumin against corticosterone-induced cytotoxicity in PC12 cells and explored the mechanisms of these protective effects in association with the phosphorylation and expression of ERK1/2 in PC12 cells. MTT assay showed that curcumin significantly protected PC12 cells from corticosterone-induced cytotoxicity. Curcumin at concentrations from 10−8 to 10−6 M rescued PC12 cells from corticosterone-induced cytotoxicity. Cell viability was increased more than 20% with curcumin treatment. Western blot analysis showed that corticosterone increased ERK1/2 phosphorylation in PC12 cells and curcumin 10−9 M to 10−6 M significantly inhibited corticosterone-induced ERK1/2 phosphorylation in PC12 cells in a dose-dependent manner. These results suggest that curcumin is able to protect PC12 cells which may be associated with inhibition of ERK phosphorylation.
Co-reporter:Hong Zhou;Ning Lu;Zhi-Qiang Chen;Qian-Liu Song;He-Ming Yu
Basic & Clinical Pharmacology & Toxicology 2009 Volume 104( Issue 2) pp:164-170
Publication Date(Web):
DOI:10.1111/j.1742-7843.2008.00348.x
Abstract: Cells growing in high density were observed to undergo a variety of responses due to cell–cell contact, pericellular hypoxia, etc. In order to investigate the influence of cell density on cell proliferation and adhesion and to elucidate possible mechanisms, we tested the growth ability of human prostate tumour (PC-3M) cells in dense culture and the influences of density on cell adhesion. Our results demonstrate that increasing cell density exerted stress on PC-3M cells, which decreased cell proliferation in dense cultures, but tended to facilitate tumour metastasis since cell adhesion ability was elevated and the cells showed an increased growth rate after being moved to a favourable growth environment. We conclude that higher cell density-mediated pericellular hypoxia was an important factor inducing expression of the intrinsic hypoxia marker osteopontin, another mechanism contributing to cell adhesion enhancement in PC-3M cells. In addition, cell density enhanced adhesion ability due to the activation of p38 mitogen-activated protein kinase (p38 MAPK) and protein kinase C. Intracellular calcium also played positive roles at least partially through activating p38 MAPK.
Co-reporter:Lu Tie, Jian-Zhao Zhang, Yan-Hua Lin, Tian-Hao Su, Yu-Hua Li, Hong-Li Wu, You-Yi Zhang, He-Ming Yu and Xue-Jun Li
Journal of Proteome Research 2008 Volume 7(Issue 4) pp:1704-1711
Publication Date(Web):2017-2-22
DOI:10.1021/pr700711s
Adrenoceptors mediate effects of endogenous catecholamines and have been shown to affect the neuronal development. Microtubule-associated protein-2 (MAP-2) is an important cytoskeleton protein whose phosphorylation in response to extracellular signal is involved in the regulation of neurite outgrowth and neuronal plasticity. The present study was designed to determine the effect of activation of adrenoceptor by epinephrine on MAP-2 phosphorylation in differentiation PC12 cells and, if so, to explore the mediating mechanism. We found that epinephrine could significantly increase the phosphorylation of MAP-2c at ser136 in a dose- and time-dependent manner in differentiated PC12 cells as well as microtubule arrays. Differentiated PC12 cells express α2A-adrenoceptor, whose antagonists could block these mentioned effects of epinephrine, and clonidine which is the agonist of α2-adrenoceptor could mimic the effect of epinephrine. Moreover phosphorylation of ERK and PKC was induced by epinephrine, and ERK and PKC specific inhibitors concentration-dependently prevented epinephrine-induced phosphorylation of MAP-2c at ser136. In addition, pretreatment of PC12 cells with epinephrine partly inhibited 30 µM nocodazole induced neurites retraction. These findings suggest that epinephrine induces phosphorylation of MAP-2c at ser136 through a α2-adrenoceptor mediated, ERK/PKC-dependent signaling pathway, which may contribute to the stabilization of neurites.
Co-reporter:Ning Lu;Hong Zhou;Yan-hua Lin;Zhi-qiang Chen;Yan Pan
Basic & Clinical Pharmacology & Toxicology 2007 Volume 101(Issue 1) pp:
Publication Date(Web):14 MAY 2007
DOI:10.1111/j.1742-7843.2007.00074.x
Abstract: Cobalt chloride (CoCl2), an agent demonstrated to stabilize hypoxia-inducible factor-1, has been associated with various hypoxic responses, and recently, some reports have linked it to increasing tumour malignancy. In this study, we observed the alteration of cell adhesion after CoCl2 treatment and analysed the potential mechanisms responsible for such adaptations in a prostate cancer cell line PC-3 M cell. We found that CoCl2 increased the tumour cell adhesion in a dose-dependent manner, which correlated with reactive oxygen species (ROS) generation. When cells were incubated with the thiol reductive agent pyrrolidine dithiocarbamate (PDTC), both the ROS generation and the CoCl2-induced cell adhesion were abolished. Moreover, p38 mitogen-activated protein kinase (p38 MAPK) was activated in CoCl2-treated cells, which could be antagonized by PDTC. And when cells were pre-incubated with specific p38 MAPK inhibitor, SB203580, the cell adhesion induced by CoCl2 was diminished. Moreover, the protein kinase C could up-regulate cell adhesion through activating p38 MAPK. In conclusion, CoCl2 induced ROS generation, thereby placing cells under oxidative stress and up-regulating cell adhesion; p38 MAPK and protein kinase C could be activated in a ROS-dependent fashion, which in turn contributed to cell adhesion induced by CoCl2.
Co-reporter:Junwei Gao, Heming Yu, Qianliu Song, Xuejun Li
Analytical Biochemistry 2005 Volume 342(Issue 1) pp:53-58
Publication Date(Web):1 July 2005
DOI:10.1016/j.ab.2005.03.033
Aquaporin (AQP) is a kind of channel-forming membrane glycoprotein that mediates osmotic water transport. The present study aimed to establish a cell line stably transfected with AQP1 to measure osmotic water permeability. The recombinant plasmid was constructed by subcloning the full-length rat AQP1 cDNA into pEGFP-C3 vector, named pEGFP/AQP1. Human embryonic kidney 293 cells were transfected with pEGFP/AQP1 and selected by G418 to obtain a cell line stably expressing AQP1 tagged with green fluorescent protein. The expression level of AQP1 in the stably transfected cell was detected by reverse transcription polymerase chain reaction and Western blot. The real-time change of fluorescence density, corresponding to cell swelling induced by hyposmotic solution, was recorded under confocal laser scanning microscope and used to assess osmotic water permeability. The typical AQP1 inhibitor, mercuric chloride, validated this osmotic water permeability assay. These results suggested that this transfected cell model could be conveniently used to determine osmotic water permeability.
Co-reporter:Lu Danyu, Li Ying, Bi Zhenwu, Yu Heming, Li Xuejun
Cell Biology International (May 2008) Volume 32(Issue 5) pp:532-541
Publication Date(Web):1 May 2008
DOI:10.1016/j.cellbi.2008.01.002
Aquaporin 1 (AQP1) is one of the water channels involved in water transfer and reabsorption. The results of a reverse transcription-polymerase chain reaction (RT-PCR) indicated that the level of AQP1 mRNA was increased in the testis and vas deferens, but decreased in the epididymis from the early postnatal period through puberty to adulthood. The results of Western blot analyses largely matched the RT-PCR findings for AQP1. AQP1 was immunohistochemically localized on the plasma membrane in the epithelia of rete testis and vas deferens at postnatal day 70, although it was hardly detectable at postnatal day 15. Nevertheless, AQP1 was expressed in the epithelia of the efferent duct and the initial segment of caput epididymis at postnatal day 15 and persisted into adulthood. The results taken together suggest that the expression and localization of AQP1 in mouse testis, epididymis and vas deferens are a stage-, tissue- and region-specific pattern and provide obvious clues that a possible relationship exists between the functional application of AQP1 for water reabsorption, and male reproduction and maturation.
Co-reporter:Jie Chen, Bing Liu, Jiayi Yuan, Jie Yang, ... Xuejun Li
Molecular Oncology (February 2012) Volume 6(Issue 1) pp:62-72
Publication Date(Web):1 February 2012
DOI:10.1016/j.molonc.2011.11.003
The high metastatic potential of non-small cell lung cancers (NSCLCs) is closely correlated with the elevated expression of vascular endothelial growth factor (VEGF) and resultant tumor angiogenesis. However, no effective strategies against VEGF expression have been available in NSCLCs therapy. This study demonstrated that elevated reactive oxygen species (ROS) levels derived from both mitochondria and NADPH oxidase were required for VEGF expression in NSCLC cells. Atorvastatin administration could significantly inhibit VEGF expression both in vitro and in vivo via inhibition of ROS production. Atorvastatin inhibited ROS generation partly through suppression of Rac1/NADPH oxidase activity. Specifically, atorvastatin could upregulate the activity of glutathione peroxidase (GPx) and catalase, which are responsible for elimination of hydrogen peroxide (H2O2) in the mitochondria and peroxisomes, respectively. Thus, inhibition of ROS production by concomitant suppression of Rac1/NADPH oxidase activity and upregulation of the activity of GPx and catalase contributes critically to atorvastatin-reduced VEGF expression in NSCLCs. Atorvastatin may be a potential alternative against VEGF expression and angiogenesis in NSCLCs therapy.Highlights► Both mitochondria and NADPH oxidase are required for VEGF expression in NSCLCs. ► Atorvastatin suppresses VEGF expression in NSCLCs via inhibition of ROS production. ► Atorvastatin inhibits ROS production mostly via suppression of NADPH oxidase. ► Atorvastatin can upregulate the activity of GPx and catalase.
Co-reporter:Yan Xu, Jingjie Zhang, Jing Han, Xueyang Pan, ... Xuejun Li
Molecular Oncology (August 2012) Volume 6(Issue 4) pp:405-417
Publication Date(Web):1 August 2012
DOI:10.1016/j.molonc.2012.03.005
Lung carcinogenesis is a complex process in an unregulated inflammatory environment. Curcumin has been extensively investigated as a multi-target anti-tumor and anti-inflammation compound. In this paper, we demonstrate a novel inflammation-related mechanism for curcumin-induced inhibition of lung tumor growth. We found that neutrophil elastase, an important regulator of inflammatory processes, directly triggered tumor cell proliferation in human lung adenocarcinoma A549 cells, and curcumin could completely suppress the excess tumor proliferation induced by neutrophil elastase. α1-antitrypsin is synthesized by tumor cells and is the natural inhibitor of neutrophil elastase. We found that curcumin counteracted the decrease of α1-antitrypsin induced by neutrophil elastase by inducing the promoter activity of α1-antitrypsin and promoting its expression in A549 cells. The inhibition of neutrophil elastase-induced proliferation by curcumin was dependent on the PI3K/Akt pathway. Knockdown of α1-antitrypsin by siRNA further enhanced the tumor cell proliferation induced by neutrophil elastase and significantly blocked the anti-proliferation effect of curcumin against neutrophil elastase. Curcumin remarkably inhibited the primary tumor growth of Lewis lung carcinoma (LLC) in C57BL/6 mice. We further showed that curcumin upregulated the level of α1-antitrypsin in primary tumor tissue by promoting its local expression, and the protein level of neutrophil elastase in tumor tissue was obviously decreased in mice treated with curcumin. Overall, our results suggest that neutrophil elastase and α1-antitrypsin play important roles in modulating lung tumor proliferation in inflammatory microenvironment and curcumin inhibits neutrophil elastase-induced tumor proliferation via upregulating α1-antitrypsin expression in vitro and in vivo.Highlights► Neutrophil elastase (NE) directly triggers lung tumor cell proliferation. ► Curcumin completely suppresses the excess tumor proliferation induced by NE. ► Curcumin blocks NE-induced tumor proliferation via upregulating α1-antitrypsin in lung cancer. ► Curcumin is a potential alternative against inflammation-related tumor growth.
Co-reporter:Haopeng Yang, Xuejun Li
Acta Pharmaceutica Sinica B (August 2012) Volume 2(Issue 4) pp:396-402
Publication Date(Web):August 2012
DOI:10.1016/j.apsb.2012.05.003
