Fas信号通路通过诱导EMT促进胃癌细胞的侵袭转移

目的探讨Fas信号通路促进胃癌细胞侵袭转移的可能相关机制。方法以低浓度FasL处理胃癌细胞株AGS,免疫印迹及ELISA检测上皮间质转化(epithelial-mesenehymal transition,EMT)的分子生物学标记改变;稳定沉默Snail及Twist转录因子,transwell小室侵袭实验检测FasL处理后胃癌细胞的侵袭能力;免疫印迹检测信号通路激活状态及相应的抑制效应。结果 FasL可以诱导AGS细胞株出现EMT表型,并可促进胃癌细胞的侵袭转移能力。同时该过程中出现ERK1/2信号通路的激活,而抑制ERK1/2信号通路,可以抑制FasL诱导EMT及提高肿瘤侵袭能力的作用。胃癌组织中相应分子生物学标记的表达变化符合EMT的发生。结论 Fas信号通路能够激活ERK1/2通路诱导EMT的发生,并且能通过该机制增强胃癌细胞AGS的活动能力。     

GSK-3β通过调节 Snail 参与 Fas 诱导的EMT过程

目的：探讨ERK、GSK3β和Snail在Fas诱导的EMT中的作用。方法选用结肠癌SW480细胞及胃癌AGS细胞作为研究对象,使用U0126以阻断其ERK/MAPK通路的激活,稳定转染GSK3βS9A以抑制其GSK3βSer9位点的磷酸化及信号转导,稳定转染Snail shRNA以抑制其Snail活性,并对接受上述处理的细胞分别给予低剂量FasL刺激后,再利用侵袭试验、免疫荧光、免疫印迹、RT-PCR、qRT-PCR、免疫共沉淀及荧光素酶报告基因等方式检测细胞的形态、功能变化。结果 Fas信号通路的激活可抑制E-cadherin的转录表达,且这一过程依赖于ERK/MAPK通路。通过转染稳定敲除Snail表达后,Fas对E-cadherin的转录抑制作用显著减弱。在细胞内过表达突变型GSK3βS9A可显著降低Fas通路激活后Snail的表达上调水平、E-cadherin的转录抑制水平及细胞的侵袭能力增加程度。免疫共沉淀提示, GSK3β与ERK、Snail在细胞核存在相互作用。结论在消化道肿瘤细胞中,Fas诱导EMT的调控机制包括ERK/MAPK通路的激活、ERK对GSK3β的磷酸化（Ser9位点）失活、GSK3β失活导致的Snail表达上调及核易位,以及Snail作用下的E-cadherin转录水平下调。     

IL-6表观遗传改变调节SOCS3在大肠癌发病机制中的作用

目的 检测大肠癌（CRC）中IL-6、SOCS3基因mRNA表达和启动子甲基化状态,以及STAT3基因mRNA表达水平,探讨大肠癌中IL-6、SOCS3基因表观遗传学改变及其对IL-6/STAT3通路的影响.方法 实时荧光定量PCR检测20例CRC癌组织及癌旁组织IL-6、SOCS3及STAT3基因mRNA水平,甲基化特异性PCR（MSP）检测SOCS3甲基化状态,亚硫酸氢盐测序（BSP）检测IL-6启动子甲基化状态.结果 与癌旁组织相比,癌组织中IL-6、STAT3 mR-NA表达显著增高（P＜0.05）,而SOCS3显著降低,IL-6与SOCS3表达呈负相关;癌组织中IL-6启动子-633、-611、-575、-575bp位点甲基化水平均降低,而SOCS3则呈现高度甲基化状态（P＜0.05）.结论 大肠癌中IL-6和SOCS3基因DNA甲基化状态异常,影响基因表达,从而诱导IL-6/STAT3信号转导通路持续活化,促进了大肠癌的发生发展.     

雨蛙素诱导的急性胰腺炎体外细胞模型的信号转导通路研究

目的 观察急性胰腺炎(AP)体外细胞模型Janus激酶/信号转导和转录激活子(JAK/STAT)信号转导通路及细胞因子表达的变化,探讨其机制.方法 应用雨蛙素处理大鼠胰腺外分泌细胞株AR42J细胞建立AP体外模型,再用雷帕霉素(RPM)及AG490干预.采用Western blotting检测细胞JAK1、磷酸化JAK1(P-JAK1)、STAT1、P-STAT1及TNF-α、IL-1β、IL-6蛋白表达水平;RT-PCR检测TNF-α、IL-1β、IL-6 mRNA表达;台盼蓝染色测定细胞存活率.结果 未经雨蛙素处理的AR42J细胞的JAK1、P-JAK1、STAT1、P-STAT1及TNF-α、IL-1β、IL-6蛋白的相对表达量分别为0.09±0.04、0.14±0.08、0.21±0.09、0.12±0.12、0.10±0.02、0.08±0.03、0.02±0.02.雨蛙素处理后,AR42J细胞上述蛋白的表达呈时间依赖性增加,24 h时的表达量分别为0.53±0.09、0.53±0.13、0.56±0.09、0.55±0.10、0.25±0.04、0.25±0.09、0.27±0.07,均较雨蛙素未处理组显著增加(P＜0.05).再分别应用RPM和AG490抑制24 h后,细胞TNF-α、IL-1β、IL-6蛋白表达量显著降低到0.17±0.03和0.17±0.01、0.15±0.05和0.14±0.07、0.19±0.04和0.19±0.05,它们的mRNA表达量也显著降低(P值均＜0.05);RPM和AG490抑制组的细胞存活率分别为(72.4±11.2)%、(69.7±9.8)%,均显著高于单用雨蛙素处理细胞组的(42.2±12.3)%(P＜0.05).结论 JAK1/STAT1信号通路早期参与雨蛙素诱导的AP细胞促炎症细胞因子释放.早期抑制JAK1/STAT1信号通路有利于控制AP的炎症反应.     

Nerve growth factor regulates CD133 function to promote tumor cell migration and invasion via activating ERK1/2 signaling in pancreatic cancer

BackgroundPerineural invasion (PNI) is extremely high frequency among the various metastatic routes in pancreatic cancer. Nerve growth factor, secreted by astroglial cells, exerts effects on tumor invasion in some cancer cells, but its function on migration and invasion in pancreatic cancer is still unclear. In the present study, we determined the effects of NGF on modulating tumor cell metastatic potential and invasion activity and explored its mechanisms in pancreatic cancer.MethodsNGF and CD133 expression were detected in tumor tissues using immunohistochemical analysis and Western blotting analysis. The effects of NGF on the regulation of CD133 expression and the promotion of cancer migration and invasion were investigated using wound healing and matrigel transwell assay. A related mechanism that NGF regulates CD133's function via activating ERK1/2 signaling also was observed.ResultsNGF/CD133 is overexpressed in human pancreatic cancer and promotes the migration and invasion of human pancreatic cancer cells through the activation of the ERK/CD133 signaling cascade. NGF/ERK signaling modulates the cancer cell EMT process, migration and invasion through the regulation of CD133 expression and its subcellular localization.ConclusionsNGF/CD133 signaling initiated the migration and invasion of pancreatic cancer cells. NGF/CD133 might be an effective and potent therapeutic target for pancreatic cancer metastasis, particularly in PNI.     

Characterization of the CXCR4 signaling in pancreatic cancer cells

CXCL12 and its receptor, CXCR4, are emerging as promising targets for modulating growth, angiogenesis, and metastasis in several human cancers. Indeed, blocking the receptor is sufficient to prevent metastasis and angiogenesis in experimental breast cancer xenografts. Recently, the biological effect of the CXCR4 in pancreatic cancer, one of the most deadly neoplastic diseases, has been reported. However, the molecular mechanism by which CXCR4 contributes to these properties is not completely understood. In this paper, we characterize the signaling pathways activated by CXCR4 in pancreatic cancer. We show that after CXCR4 activation, EGFR becomes tyrosine phosphorylated, and the kinase activity of this receptor, together with the activation of MMPs, Src, and PI3-Kinase, is required for CXCR4-mediated ERK activation. Analysis of this cascade in pancreatic cancer cells revealed that the ERK-mediated pathway regulates genes involved in angiogenesis, such as VEGF, CD44, HIF1α, and IL-8. Furthermore, ERK blockage inhibits the migration and tube formation of endothelial cells induced by CXCL12. Considering that inhibitors for several components of this pathway, including CXCR4 itself, are at different stages of clinical trials, this study provides theoretical justification for the clinical testing of these drugs in pancreatic cancer, thus extending the list of potential targets for treating this dismal disease.     

Fibroblast-derived CXCL12/SDF-1α promotes CXCL6 secretion and co-operatively enhances metastatic potential through the PI3K/Akt/m TOR pathway in colon cancer

AIM To investigate the underlying mechanism by which CXCL12 and CXCL6 influences the metastatic potential of colon cancer and internal relation of colon cancer and stromal cells. METHODS Western blotting was used to detect the expression of CXCL12 and CXCL6 in colon cancer cells and stromal cells. The co-operative effects of CXCL12 and CXCL6 on proliferation and invasion of colon cancer cells and human umbilical vein endothelial cells(HUVECs) were determined by enzyme-linked immunosorbent assay,and proliferation and invasion assays. The angiogenesis of HUVECs through interaction with cancer cells and stromal cells was examined by angiogenesis assay. We eventually investigated activation of PI3K/Akt/m TOR signaling by CXCL12 involved in the metastatic process of colon cancer.RESULTS CXCL12 was expressed in DLD-1 cancer cells and fibroblasts. The secretion level of CXCL6 by colon cancer cells and HUVECs were significantly promoted by fibroblasts derived from CXCL12. CXCL6 and CXCL2 could significantly enhance HUVEC proliferation and migration(P 0.01). CXCL6 and CXCL2 enhanced angiogenesis by HUVECs when cultured with fibroblast cells and colon cancer cells(P 0.01). CXCL12 also enhanced the invasion of colon cancer cells. Stromal cell-derived CXCL12 promoted the secretion level of CXCL6 and co-operatively promoted metastasis of colon carcinoma through activation of the PI3K/Akt/m TOR pathway.CONCLUSION Fibroblast-derived CXCL12 enhanced the CXCL6 secretion of colon cancer cells,and both CXCL12 and CXCL6 co-operatively regulated the metastasis via the PI3K/Akt/m TOR signaling pathway. Blocking this pathway may be a potential anti-metastatic therapeutic target for patients with colon cancer.     

Celecoxib suppresses proliferation and metastasis of pancreatic cancer cells by down-regulating STAT3 / NF-kB and L1CAM activities

Objective

To explore the molecular mechanisms of celecoxib-induced pancreatic cancer suppression in vivo and in vitro.

胃泌素对胃癌细胞EMT和Wnt/β-catenin信号通路相关基因表达的影响

目的探讨高表达胃泌素(gastrin)对胃癌细胞上皮间质转化(EMT)的影响及可能机制。方法用gastrin过表达质粒pcDNA3-gastrin及空载体pcDNA3.1转染胃癌细胞SGC-7901、MKN45,48 h后收集细胞蛋白,Western印迹检测鉴定gastrin表达,检测EMT相关标志物E-钙黏蛋白(cadherin)、N-cadherin、Snail及wnt/β-连环蛋白(catenin)信号通路相关基因wnt3α、β-catenin、c-myc的蛋白表达变化。结果在SGC-7901、MKN45细胞中成功过表达gastrin。与pcDNA3.1空载体转染组相比,pcDNA3.1-gastrin转染SGC-7901、MKN45细胞中上皮标志蛋白E-cadherin表达下调,间质标志蛋白N-cadherin、Snail表达上调,差异有统计学意义(P<0.05);同时Wnt/β-catenin通路蛋白相关蛋白wnt3α、β-catenin及其下游基因c-myc的表达上调,差异有统计学意义(P<0.05)。结论过表达gastrin能够激活Wnt/β-catenin信号通路和促进胃癌细胞SGC-7901和MKN45发生EMT。