Delta-catenin蛋白通过抑制JNK通路活性而减少肺癌细胞的凋亡

背景与目的：作为黏附蛋白catenin家族中的一员,Delta-catenin蛋白可以促进肿瘤细胞的增殖和侵袭,然而其提高肿瘤细胞增殖能力的机制并不清楚。本研究检测了Delta-catenin对肺癌细胞凋亡的影响及其与丝裂原活化蛋白激酶(mitogen-activated protein hinase,MAPK)信号通路蛋白的关系,并初步探索了Delta-catenin促进肿瘤细胞侵袭增殖的可能机制。方法：采用蛋白[质]印迹法(Western blot)检测肺癌细胞过表达Delta-catenin前后p38、c-jun氨基末端激酶(c-jun N-terminal kinase,JNK)蛋白活性的变化,同时利用流式细胞术检测了肿瘤细胞凋亡数量的改变,还通过Matrigel基质胶侵袭实验检测了肿瘤细胞侵袭数量的变化。结果：与未处理组和空载体对照组相比,过表达Delta-catenin后肺癌细胞的p38蛋白活性没有变化(P＞0.05),但JNK的蛋白活性却显著减少(P＜0.05),与此同时,肿瘤细胞的凋亡比例显著下降(P＜0.05),而肿瘤细胞的侵袭能力却明显增强(P＜0.05)。结论：Delta-catenin可能通过抑制肺癌细胞JNK通路的活性而减少肿瘤细胞的凋亡,进而促进肿瘤细胞的侵袭。     

扇贝多肽通过调节c-jun和COX-2抑制UVA诱导的HaCaT细胞凋亡

目的复制UVA诱导的HaCaT细胞凋亡模型,研究UVA对细胞内c-jun和环氧合酶-2(cyclooxygenase-2,COX-2)的影响,从而探究扇贝多肽(Polypeptide from Chlamys far-reri,PCF)抑制UVA引起的HaCaT细胞凋亡的分子机制。方法实验分为5组:正常对照组、UVA模型组、UVA+5.69mmol.L-1PCF组、UVA+2.84mmol.L-1PCF组、UVA+1.42mmol.L-1PCF组。应用实时荧光定量PCR和蛋白印迹法检测细胞内c-jun的表达;RT-PCR结合蛋白质印迹法检测细胞内COX-2的表达;琼脂糖凝胶电泳分析PCF和COX-2特异性抑制剂celecoxib对UVA诱导HaCaT细胞凋亡的影响。结果预先加入PCF和celecoxib均可明显抑制8J.cm-2UVA诱导的HaCaT细胞凋亡;UVA照射HaCaT细胞后COX-2mRNA及蛋白表达水平增加,与对照组相比差异有显著性(P<0.01);1.42~5.69mmol.L-1剂量范围内的PCF可剂量依赖性抑制UVA引起的细胞内COX-2mR-NA及蛋白表达(P<0.05,P<0.01);PCF也抑制了UVA引起的HaCaT细胞内c-jun表达的增加,且呈量效关系(P<0.05,P<0.01)。结论UVA诱导HaCaT细胞发生凋亡时,细胞内COX-2和c-jun的表达明显增加,PCF通过抑制细胞内COX-2和c-jun的表达而发挥其抗凋亡作用。     

Mitogen-activated protein kinases mediate arsenic-induced down-regulation of survivin in human lung adenocarcinoma cells

Survivin is a member of the inhibitors of apoptosis protein (IAP) family and is highly expressed in various cancer cells. However, the molecular mechanisms regulating survivin expression remain unclear. In this study, we investigated the role of mitogen-activated protein kinases (MAPKs) in regulating survivin in the human lung adenocarcinoma cell line H1355 in response to arsenic trioxide (As⁽³⁺⁾). Our data indicated that As⁽³⁺⁾ induced cytotoxicity accompanied by down-regulation of survivin, cleavage of Poly ADP-ribosyl polymerase (PARP) and activations of MAPKs, including ERK1/2, p38 and c-jun N-terminal kinase (JNK). We found that blockage of p38 or JNK activation attenuated the As⁽³⁺⁾-induced survivin down-regulation and PARP cleavage with significant reversal of cell viability, however, by only 5–8%. On the other hand, the MEK inhibitor PD098059 or the ubiquitin-proteasome inhibitor MG-132 exhibited little effect on survivin down-regulation and PARP cleavage induced by As⁽³⁺⁾. In this study, we demonstrated that As⁽³⁺⁾ could down-regulate survivin via activations of p38 and JNK in an ubiquitin-proteasome independent pathway and lead to cytotoxicity and apoptosis in the human lung adenocarcinoma cell line H1355.     

加味补肝汤对糖尿病大鼠坐骨神经中c—jun表达的影响

目的观察加味补肝汤对糖尿病大鼠坐骨神经中c-jun mRNA表达的影响，探讨其对实验性糖尿病大鼠周围神经病变的防治作用。方法以链脲佐菌素诱发糖尿病模型。分别于治疗后4周、8周两个时间点处死大鼠，用逆转录-聚合酶链反应（RT-PCR）技术测定坐骨神经中c-jun mRNA的表达，用黄嘌呤氧化酶法测定血清SOD活力。结果治疗后4、8周模型组大鼠c-jun mRNA表达明显高于正常对照组（P〈0．05），加味补肝汤组c-jun mRNA表达明显低于同期模型组（P〈0．05）；治疗后4、8周模型组大鼠SOD活力明显低于正常对照组（P〈0．05），加味补肝汤组SOD活力明显高于同期模型组（P〈0．05）。结论加味补肝汤对实验性糖尿病大鼠周围神经病变有一定的防治作用。     

The adaptor Lnk (SH2B3): an emerging regulator in vascular cells and a link between immune and inflammatory signaling

A better knowledge of the process by which inflammatory extracellular signals are relayed from the plasma membrane to specific intracellular sites is a key step to understand how inflammation develops and how it is regulated. This review focuses on Lnk (SH2B3) a member, with SH2B1 and SH2B2, of the SH2B family of adaptor proteins that influences a variety of signaling pathways mediated by Janus kinase and receptor tyrosine kinases. SH2B adaptor proteins contain conserved dimerization, pleckstrin homology, and SH2 domains. Initially described as a regulator of hematopoiesis and lymphocyte differentiation, Lnk now emerges as a key regulator in hematopoeitic and non hematopoeitic cells such as endothelial cells (EC) moderating growth factor and cytokine receptor-mediated signaling. In EC, Lnk is a negative regulator of TNF signaling that reduce proinflammatory phenotype and prevent EC from apoptosis. Lnk is a modulator in integrin signaling and actin cytoskeleton organization in both platelets and EC with an impact on cell adhesion, migration and thrombosis. In this review, we discuss some recent insights proposing Lnk as a key regulator of bone marrow-endothelial progenitor cell kinetics, including the ability to cell growth, endothelial commitment, mobilization, and recruitment for vascular regeneration. Finally, novel findings also provided evidences that mutations in Lnk gene are strongly linked to myeloproliferative disorders but also autoimmune and inflammatory syndromes where both immune and vascular cells display a role. Overall, these studies emphasize the importance of the Lnk adaptor molecule not only as prognostic marker but also as potential therapeutic target.     

Immunohistochemical Localization of Selected Early Response Genes Expressed in Trabecular Bone of Young Rats Given hPTH 1-34

Intermittent administration of parathyroid hormone (PTH) increases trabecular bone mass in vivo by stimulating bone formation. To further characterize the cellular and molecular mediators of the anabolic response to PTH, we examined the effect of intermittent synthetic hPTH 1-34 on the expression and localization of selected early response genes, c-fos, c-jun, c-myc, and IL-6 protein, in bone tissue by immunohistochemistry. Young male Sprague-Dawley rats, 70–100 g, were injected s.c. with 8 μg/100 g PTH or vehicle control, once daily for 5 days. Femurs were harvested 1 and 24 hours after the fifth injection, then fixed, decalcified, processed for wax embedding, and sections were immunostained. Early response genes, c-fos, c-jun and IL-6, were strongly expressed in osteoblasts, osteocytes, and megakaryocytes in bones 1 hour after PTH, when compared with vehicle-treated controls or sections from rats, 24 hours after PTH injection. Osteoblasts, osteocytes, and megakaryocytes were also positive for c-myc but the differences in stain intensity between control and treated groups were marginal. Also, scattered islands of hematopoietic cells in the marrow stained intensely for IL-6 by 1 hour after PTH, but the stain intensity decreased to control level 24 hours after the last PTH injection. Scattered islands of hematopoietic cells in the bone marrow stained more strongly for c-fos than either c-jun or c-myc, but neither localization nor stain intensity were regulated by PTH at the time points examined. We conclude that during the immediate early phase of the anabolic response, PTH regulates c-fos, c-jun, and IL-6 expression in osteoblasts, osteocytes, megakaryocytes, and selected bone marrow hematopoietic cells in bone. Received: 7 July 1998 / Accepted: 10 June 1999     

Heat shock protein expression in hearts hypertrophied by genetic and nongenetic hypertension

Summary Genetically hypertensive animals are characterized by greater thermosensitivity and overexpression of heat shock proteins (HSP) upon thermal stimulation. We examined HSP72 expression under conditions of brief coronary occlusion or thermal stimulation, and the effects of the severity of these stimuli and of myocardial hypertrophy on the expression in hearts of spontaneously hypertensive rat (SHR) and Wistar Kyoto rat (WKY) groups, A snare was created around the left coronary artery in the SHR (n=16) and WKY (n=19) groups. In 7 WKY rats, the ascending aorta was banded and a snare was created simultaneously (WKY-AoB). By tying the snare, 4 weeks later, we applied 5- or 10-min coronary occlusion without opening the chest. For thermal stimulation, the SHR (n=13) and WKY (n=11) rats were placed in a 42°C chamber for 15 or 40 min. The mRNA or protein level was estimated 1 or 24h after stimulation. In the SHR vs WKY groups, the mRNA and protein levels were higher after 5-min occlusion or 15-min thermal stimulation. After 10-min occlusion or 40-min thermal stimulation the difference was no longer observed. The overexpression was not observed in the WKY-AoB group despite the presence of hypertrophy similar to that seen in the SHR group (3.11±0.11 vs 3.20±0.06 mg/g in left ventricular weight/body weight). The HSP72 was overexpressed in hearts of genetically hypertensive animals after brief ischemia. Differential expression between the two groups was observed after mild stimuli, but not after more severe stimuli. Cardiac hypertrophy was not a major factor for determining the overexpression of HSP72.