Metformin induces apoptosis of lung cancer cells through activating JNK/p38 MAPK pathway and GADD153

There are epidemiological and experimental evidences that metformin, an insulin-sensitizer agent widely used for diabetes treatment, has inhibitory effects on the growth of various human cancers. However, the underlying molecular mechanisms for its anti-neoplastic activity has not been yet clarified and the effect of metformin on human lung cancer remains unknown. In this study we revealed for the first time that metformin treatment led to increased apoptosis in human lung cancer cell lines A549 and NCI-H1299 and significantly inhibited the cells proliferation in a?dose- and time-dependent manner, which was further demonstrated by the data obtained from A549 tumor xenografts in nude mice. We also found that metformin treatment can activate AMP-activated protein kinase, JNK/p38 MAPK signaling pathway and caspases, as well as upregulate the expression of growth arrest and DNA damage inducible gene 153 (GADD153). Either blockade of JNK/p38 MAPK pathway or knockdown of GADD153 gene abrogated the apoptosis-inducing effect of metformin. Taken together, our data suggest that metformin inhibits the growth of lung cancer cells and induces apoptosis through activating JNK/p38 MAPK pathway and GADD153.     

Stabilization of IFN-gamma mRNA by MAPK p38 in IL-12- and IL-18-stimulated human NK cells

The rapid induction of interferon-gamma (IFN-gamma) by innate cytokines such as interleukin 12 (IL-12) and IL-18 is critical for immunity against infectious pathogens. We investigated the molecular mechanisms underlying this response. IL-12 and IL-18 rapidly and synergistically induced the secretion of IFN-gamma by freshly purified human peripheral blood lymphocytes. At early time points, IFN-gamma was expressed almost exclusively by natural killer cells and in both CD56bright and CD56dim subpopulations. Mitogen-activated protein kinase p38 was activated strongly by IL-18 and weakly by IL-12 in natural killer cells but was not activated by either cytokine in T cells. The expression of IFN-gamma mRNA and protein was dose-dependently blocked by SB203580, a specific inhibitor of mitogen-activated protein kinase p38, which also caused a dramatic destabilization of IFN-gamma mRNA. The 3' untranslated region (UTR) of IFN-gamma mRNA conferred p38 responsiveness to a heterologous reporter mRNA. Therefore, the synergistic induction of IFN-gamma by IL-12 and IL-18 in natural killer cells is mediated at least in part by p38-dependent and 3' UTR-mediated stabilization of IFN-gamma mRNA.     

血管紧张素-(1-7)对人脐动脉平滑肌细胞p38MAPK通路的抑制作用

目的 探讨血管紧张素-(1-7)[Ang-(1-7)]阻断血管紧张素Ⅱ(AngⅡ)致炎作用的可能机制.方法 用DMEM培养基培养血管平滑肌细胞(VSMCs),待细胞生长至80％融合时无血清培养12小时后分为两组:Ⅰ组:对照组、AngⅡ组、Ang-(1-7)组、AngⅡ+Ang-(1-7)组、AngⅡ+ Ang-(1-7)+ A-779组、A-779组;Ⅱ组:对照组、AngⅡ组、AngⅡ+不同浓度Ang-(1-7)组.上述两组作用一定时间后收集细胞,用Western blot方法测定细胞p38丝裂原活化蛋白激酶(p38MAPK)蛋白磷酸化表达.结果 Ang-(1-7)(1000 nmol/L)可拮抗AngⅡ(100 nmol/L)诱导的VSMCs p38MAPK磷酸化表达,且呈剂量依赖性,随着Ang-(1-7)剂量的增加,p38MAPK磷酸化表达逐渐减弱.结论 Ang-(1-7)呈剂量依赖性抑制AngⅡ激活人脐动脉平滑肌细胞p38MAPK通路的作用,从而可能拮抗AngⅡ的致炎作用.     

Apogossypol derivative BI-97C1 (Sabutoclax) targeting Mcl-1 sensitizes prostate cancer cells to mda-7/IL-24-mediated toxicity

Limited options are available for treating patients with advanced prostate cancer (PC). Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24), an IL-10 family cytokine, exhibits pleiotropic anticancer activities without adversely affecting normal cells. We previously demonstrated that suppression of the prosurvival Bcl-2 family member, myeloid cell leukemia-1 (Mcl-1), is required for mda-7/IL-24-mediated apoptosis of prostate carcinomas. Here we demonstrate that pharmacological inhibition of Mcl-1 expression with the unique Apogossypol derivative BI-97C1, also called Sabutoclax, is sufficient to sensitize prostate tumors to mda-7/IL-24-induced apoptosis, whereas ABT-737, which lacks efficacy in inhibiting Mcl-1, does not sensitize mda-7/IL-24-mediated cytotoxicity. A combination regimen of tropism-modified adenovirus delivered mda-7/IL-24 (Ad.5/3-mda-7) and BI-97C1 enhances cytotoxicity in human PC cells, including those resistant to mda-7/IL-24 or BI-97C1 alone. The combination regimen causes autophagy that facilitates NOXA- and Bim-induced and Bak/Bax-mediated mitochondrial apoptosis. Treatment with Ad.5/3-mda-7 and BI-97C1 significantly inhibits the growth of human PC xenografts in nude mice and spontaneously induced PC in Hi-myc transgenic mice. Tumor growth inhibition correlated with increased TUNEL staining and decreased Ki-67 expression in both PC xenografts and prostates of Hi-myc mice. These findings demonstrate that pharmacological inhibition of Mcl-1 with the Apogossypol derivative, BI-97C1, sensitizes human PCs to mda-7/IL-24-mediated cytotoxicity, thus potentially augmenting the therapeutic benefit of this combinatorial approach toward PC.     

Soluble Fas ligand activates the sphingomyelin pathway and induces apoptosis in luteal steroidogenic cells independently of stress-activated p38(MAPK)

Fas ligand (FasL) is implicated as a mediator of luteolysis. However, a gap exists in our understanding of the Fas-mediated signaling mechanisms that are involved in either the loss of progesterone production or the structural regression of the corpus luteum. In the present study we investigated the acute and chronic effects of FasL with respect to activation of cytokine/stress-induced signaling pathways and apoptosis in bovine steroidogenic cells. More specifically, we investigated soluble FasL (sFasL)-activated production of ceramide, a second messenger of the sphingomyelin pathway, and activation of p38(MAPK), a member of the MAPK family. sFasL activated the sphingomyelin pathway, as evidenced by a 2-fold increase (P < 0.05) in the production of ceramide. Pretreatment with imipramine (50 micro M), an inhibitor of acid sphingomyelinase activity, attenuated (75%; P < 0.05) sFasL-induced ceramide production, suggesting that the increase in ceramide was partially the result of acid sphingomyelinase-mediated hydrolysis of sphingomyelin. Treatment of luteal cells with sFasL or a cell-permeable ceramide analog (C8) for 24-48 h resulted in a significant increase (P < 0.05) in apoptosis. Western blot analysis revealed that sFasL had little effect on the activation of p38(MAPK) in primary bovine luteal steroidogenic cells. Furthermore, pretreatment with the p38(MAPK) inhibitor SB203580 failed (P > 0.05) to inhibit sFasL- or C8-induced death. Although sFasL did not alter basal progesterone levels detected in the culture medium, C8 caused a significant increase (P < 0.05) in progesterone concentrations within the medium. Collectively, these data suggest that the role of FasL in luteolysis may be to activate the stress-induced sphingomyelin pathway that, in turn, serves as a mediator of apoptosis.     

p38丝裂原活化蛋白激酶在顺铂诱导癌周肝硬化肝细胞株凋亡中的作用

目的 探讨p38丝裂原活化蛋白激酶(MAPK)通路在顺铂诱导正常肝细胞、癌周肝硬化肝细胞和肝癌细胞凋亡过程中的作用.方法 应用流式细胞仪、电镜、免疫细胞化学、激光扫描共聚焦显微镜和Western blot检测正常肝细胞株HL-7702、癌周肝硬化肝细胞株QSG-7701和肝癌细胞株QGY-7703加入顺铂和p38MAPK特异性抑制剂SB203580后的凋亡情况,以及p38MAPK、细胞分裂周期25同源体B(CDC25B)、p34cdc2和细胞周期素B1的表达.组间数据的比较采用单因素方差分析和SNK-q检验,P＜0.05为差异有统计学意义.结果 正常肝细胞、癌周肝硬化肝细胞和肝癌细胞株加顺铂后,凋亡率均明显增加,以癌周肝硬化肝细胞株最明显(从0.8%增高到41.5%);用顺铂+SB203580处理后,癌周肝硬化肝细胞株的凋亡率降低(28.1%),细胞周期阻滞于S期.电镜、免疫细胞化学、激光扫描共聚焦显微镜均观察到细胞凋亡形态.癌周肝硬化肝细胞分别用顺铂和顺铂+SB203580后,p38MAPK相对表达量分别为0.51±0.05和0.53±0.04,CDC25B相对表达量分别为0.61±0.04和0.59±0.03,p34cdc2相对表达量分别为1.08±0.16和1.21±0.15,与空白对照组(p38MAPK、CDC25B和p34cdc2的相对表达量分别为0.43±0.02、0.28±0.05和1.01±0.12)比较,差异有统计学意义(F=20.056,P＜0.05).结论 顺铂通过p38MAPK通路诱导癌周肝硬化肝细胞凋亡,而正常肝细胞和肝癌细胞的凋亡诱导途径可能不同.     

p38MAPK对大鼠肾小球系膜细胞表达COX-2的影响

目的 探讨p38丝裂原活化蛋白激酶（p38MAPK）和环氧化酶2（COX-2）的关系,从而研究p38MAPK和COX-2在糖尿病肾病（DN）中的作用机制.方法 分别以高葡萄糖、高胰岛素、过氧化氢和糖基化终产物孵育大鼠肾小球系膜细胞系HBZY-1;先以p38MAPK特异抑制剂SB203580预处理细胞系HBZY-1,再给予上述4种因素孵育细胞系HBZY-1,观察细胞系HBZY-1 p38MAPK和COX-2的表达.结果 高葡萄糖、高胰岛素、过氧化氢和糖基化终产物均可独立激活p38MAPK,使其磷酸化表达量增加,COX-2表达也明显增加;SB203580预处理后,COX-2表达被显著抑制.结论 p38MAPK调控COX-2的表达,表明p38MAPK是COX-2的上游激酶之一,p38MAPK和COX-2可能在DN的发生发展过程中起重要作用.     

Involvement of p38 MAPK,JNK, p42/p44 ERK and NF-kappaB in IL-1beta-induced chemokine release in human airway smooth muscle cells

Asthma is an inflammatory disease, in which eotaxin, MCP-1 and MCP-3 play a crucial role. These chemokines have been shown to be expressed and produced by IL-1beta-stimulated human airway smooth muscle cells (HASMC) in culture. In the present study we were interested to unravel the IL-1beta-induced signal transduction leading to chemokine production. Using Western blot, we observed an activation of p38 MAPK, JNK kinase and p42/p44 ERK when HASMC were stimulated with IL-1beta. We also observed a significant decrease in the expression and the release of eotaxin, MCP-1 and MCP-3 in the presence of SB203580, an inhibitor of p38 MAPK (71 +/- 6%, P < 0.05, n = 8 and 39 +/- 10% P < 0.01, n = 10 respectively), curcumin, an inhibitor of JNK kinase (83 +/- 4.9% and 88 +/- 3.4% respectively, P < 0.01, n = 4). U0126, an inhibitor of p42/p44 ERK, also produced a significant decrease in chemokine production (46.3 +/- 9%, P < 0.01 n = 10 and 67.8 +/- 12%, P < 0.01, n = 12). Pyrrolydine dithiocarbamate, an inhibitor of NF-kappaB was also able to reduce the eotaxin, MCP-1 and MCP-3 expression and production (50 +/- 13%, P < 0.05, n = 10 and 23 +/- 7%, P < 0.05, n = 12). We conclude that p38 MAPK, JNK kinase, ERK and NF-kappaB are involved in the IL-1beta-induced eotaxin, MCP-1, and MCP-3 expression and release in HASMC.     

冲击波通过P2X7受体激活人骨髓间充质干细胞的p38 MAPK通路

目的探讨体外冲击波是否通过促使ATP向细胞外释放激活P2X7受体信号通路并诱导人骨髓间充质干细胞(hMSCs)p38 MAPK激酶活化。方法用即时RT-PCR检测P2X7受体mRNA的表达;通过免疫印迹法评估P2X7受体和p38 MAPK激酶的表达;用ATP水解酶、P2X7受体的siRNA、p38 MAPK激酶抑制剂以及P2受体的抑制剂评估ATP释放、P2X7受体在冲击波诱导hMSCs p38 MAPK激酶磷酸化中的作用。结果 (能量密度0.18 mJ/mm2,作用0、50、100或150次)冲击波可引起细胞内的ATP(⁶.9μmol/L)向外释放,冲击波(能量密度0.18 mJ/mm2,作用0、50、100或150次)和细胞外的ATP(0.16.9μmol/L)向外释放,冲击波(能量密度0.18 mJ/mm2,作用0、50、100或150次)和细胞外的ATP(0.1¹μmol/L)能够促使p38 MAPK激酶活化。用ATP水解酶消除细胞外ATP、用siRNA或抑制剂抑制P2X7受体抑制p38 MAPK激酶的活化。结论冲击波引起的细胞内ATP向外释放,能够有效激活P2X7受体传导信号通路,引起hMSCs向成骨细胞的p38MAPK激酶活化,这可能是冲击波疗法的机制所在。     

Fas (CD95)- and tumor necrosis factor-mediated apoptosis in liver endothelial cells: role of caspase-3 and the p38 MAPK.

Recently, we showed that TNF enhances the susceptibility of endothelial cells from murine liver sinusoids (LEC) to Fas-mediated apoptosis, suggesting that signals transduced by Fas and TNF receptors may synergistically increase intracellular death signals in these cells. In this work we evaluated whether caspase-3 and p38 are involved in LEC apoptosis induced by Fas and TNF. Here we show that LEC treated with Fas agonist (Jo2 mAb at 0.1 microg/ml) and TNF had a greater caspase-3 activity (twofold increase) than cells treated with each factor alone. There was a strong correlation between caspase-3 activity and cell killing induced by Jo2/TNF, indicating that this caspase plays a critical role in this process. Likewise, there was a significant increase in caspase-8 activity in LEC treated with Jo2 and TNF, compared with untreated cells or cells treated with each factor alone. Apoptosis of LEC induced by Jo2/TNF was partially reversed by SB203580, a p38 inhibitor, suggesting that p38 is involved in apoptosis of these cells. To our knowledge, this is the first report that apoptosis induced by Fas/TNF in LEC is associated with coactivation of both caspase-3 and p38. Potentially, both caspase-3 and p38 may be of great importance in endothelial cell pathology as molecular targets for preventing vascular damage due to endothelial cell apoptosis.     

亚硒酸钠对大鼠肾小球系膜细胞p38MAPK和COX-2表达的调控

目的探讨p38丝裂原活化蛋白激酶(p38 mitogen-activated protein kinase,p38MAPK)和环氧化酶-2(cvclooxygenase-2,COX-2)的关系,从而研究p38MAPK和COX-2在糖尿病肾病中的作用及硒在防治糖尿病肾病中的作用机制。方法分别以高葡萄糖、高胰岛素、过氧化氢和糖基化终末产物孵育大鼠肾小球系膜细胞系HBZY-1;先给予p38MAPK特异性抑制剂SB203580和亚硒酸钠分别预处理细胞系HBZY-1后,再给予上述4种因素孵育细胞系HBZY-1,观察细胞系HBZY-1 p38MAPK和COX-2的蛋白表达。结果高葡萄糖、高胰岛素、过氧化氢和糖基化终末产物均可独立激活p38MAPK,使其磷酸化表达量增加,COX-2蛋白表达也明显增加;SB203580预处理后,COX-2蛋白表达被显著抑制;亚硒酸钠预处理后,p38MAPK磷酸化被明显抑制,同时COX-2蛋白表达明显降低。结论p38MAPK调控COX-2的表达,表明p38MAPK是COX-2的上游激酶之一,p38MAPK和COX-2在糖尿病肾病的发生发展过程中起重要作用;亚硒酸钠可通过抑制p38MAPK而抑制COX-2表达,从而表明硒能有效地防治糖尿病肾病。     

Mycobacterium bovis-mediated induction of human beta-defensin-2 in epithelial cells is controlled by intracellular calcium and p38MAPK

Induction of human beta defensin-2 (HBD-2) by mycobacteria has been reported. However, the molecular mechanism(s) by which mycobacteria up-regulates HBD-2 gene expression in epithelial cells remains poorly understood. In this work, we provide evidence that the induction of HBD-2 mRNA in response to Mycobacterium bovis bacillus Calmette-Guerin (BCG) was inhibited in a dose-dependent manner by pretreatment with a cell-permeable BAPTA-AM, which chelates intracellular calcium. Our data also demonstrate that HBD-2 mRNA induction by M. bovis in A549 lung epithelial cells requires activation of calmodulin. Interestingly, HBD-2 mRNA expression in response to M. bovis BCG was attenuated by pretreatment with SB203580 (an inhibitor of p38 mitogen-activated protein kinase [MAPK]), but not by an inhibitor of extracellular signal-regulated kinase (ERK): PD98059. Furthermore, we found that a second p38 MAPK inhibitor (SB202190) significantly blocked M. bovis BCG-mediated HBD-2 induction in A549 lung epithelial cells. Together, these data suggest that M. bovis BCG induces HBD-2 mRNA expression in A549 lung epithelial cells at least in part mediated through intracellular calcium flux as well as activation of signaling protein of p38MAPK, but not ERK.     

p38信号通路在内皮细胞微粒诱导人脐静脉内皮细胞表达细胞间黏附分子-1中的作用

目的观察p38信号通路（P38MAPK）在内皮细胞微粒（EMPs）诱导人脐静脉内皮细胞（HU—VECs）表达细胞间黏附分子-1（ICAM-1）中的作用。方法将体外培养的HUVECs随机分组：①EMPs不同时点观察组：用EMPs（终浓度105／m1）分别刺激细胞0、3、6、12、24h;②EMPs不同剂量作用组：分别用终浓度为0、10^2、10^3、10^4、10^5／ml的EMPs刺激细胞24h;③EMPs＋p38MAPK特异性抑制剂SB203580组：在EMPs（终浓度10^5／ml）刺激前,与终浓度为5μmol／L的SB203580共同孵育30min。用蛋白免疫印迹法（Western blot）测定p38MAPK磷酸化表达,实时荧光定量PCR测定ICAM—1mRNA的表达。结果EMPs可激活p38MAPK,使磷酸化p38MAPK蛋白表达量及ICAM—1mRNA表达量增加,且呈剂量和时间依赖性。p38MAPK特异性拈抗剂SB203580可显著抑制EMPs的此作用。结论p38信号通路可能部分参与了对EMPs诱导HUVECs表达ICAM-1的调控。     

Development of innate CD4+ alpha-chain variable gene segment 24 (Valpha24) natural killer T cells in the early human fetal thymus is regulated by IL-7

Natural killer (NK) T cells are innate CD1d-restricted immune cells involved in regulation of immune tolerance, tumor immunity, and immunity to infectious pathogens. Human alpha-chain variable gene segment 24 (Valpha24) NK T cells exist in the periphery as two functionally distinct subsets: one CD4+ and one CD4- subset. However, the developmental pathway of human Valpha24 NK T cells is not well understood. Here, we show that Valpha24 NK T cells develop in the fetal thymus. The relative number of intrathymic NK T cell precursors decline in a linear manner with gestational age, and they are very rare in the neonatal thymus, indicating that these cells preferentially develop in the early fetal thymus. Their restriction element, CD1d, is expressed by a vast majority of thymocytes. A majority of intrathymic Valpha24 NK T cell progenitors are CD4+, whereas a minority are CD4/8(+/+). CD4+ Valpha24 NK T cell precursors show features of mature NK T cells, such as high levels of their semiinvariant T cell receptor and CD3 and some expression of CD161, whereas the CD4/8(+/+) precursors seem less mature. The cytokine IL-7 shows a biphasic effect on Valpha24 NK T cell progenitors in fetal thymic organ culture, with high doses driving proliferation of immature CD161-progenitors and low doses supporting survival and maturation. Thus, the data demonstrate that human Valpha24 NK T cells of the CD4+, but not the CD4-, subset develop in the early fetal thymus. Furthermore, data suggest an intrathymic pathway of CD4+ Valpha24 NK T cell development that is regulated by IL-7.