癌基因Stat3与肿瘤治疗

Star3信号传导通路接受生长因子、细胞因子等细胞外信号刺激，作用于细胞核内特异的DNA片段，调控靶基因如cyclin D1与bcl—X等的转录，直接影响细胞的增殖、分化与凋亡。研究结果显示Star3蛋白异常激活与多种恶性肿瘤发生、发展密切相关，被定义为癌基因，目前已有学者以Star3为靶点进行肿瘤治疗研究，取得了初步结果，但有关Star3的详细作用机制尚未明确，有待于进一步深入研究。     

转录信号传导子与激活子3在宫颈癌及宫颈癌上皮内瘤变中的表达及临床意义

目的探讨转录信号传导子与激活子3(Stat3)在宫颈鳞状细胞癌和宫颈上皮内瘤变(CIN)中的表达及与临床病理特征的关系,及其在宫颈癌病变中的可能作用。方法应用免疫组织化学SP法,检测44例宫颈鳞状细胞癌,50例宫颈上皮内瘤变,15例正常宫颈组织中Stat3蛋白的表达水平。结果Stat3在宫颈鳞状细胞癌组中的阳性表达率为84.1%(37/44),明显高于宫颈上皮内瘤变组,P<0.05;亦明显高于正常宫颈组织,P<0.01;同时发现Stat3表达率与宫颈癌组织学分期有关,P<0.05。结论Stat3过表达可能在宫颈鳞状细胞癌的发生、发展及分化过程中起重要作用。     

STAT3与肿瘤的关系

目前在分子水平及信号传导通路方面研究疾病的病因和发病机制已成为国内外研究的热点.其中,STAT3信号传导途径参与体内多种细胞因子的信号转导过程,在调节细胞的增殖、分化、存活和凋亡中具有重要作用,是体内多条致癌性信号传导通路汇聚的焦点,在多种肿瘤细胞中均发现了STAT3蛋白的持续性激活.研究表明,STAT3通路的激活与肿瘤的发生、发展及恶性生物学行为密切相关,并有望成为肿瘤治疗的新靶点.     

肝细胞癌中MAPK和Stat3磷酸化与c-fos和c-jun蛋白表达的关系

目的:探讨肝细胞癌中MAPK和Stat3磷酸化与c-fos和c-jun蛋白表达的关系。方法:利用SP免疫组织化学技术检测55例肝细胞癌(hepatocellulancarcinoma,HCC)及其癌旁肝组织中p42/44MAPK、p-Stat3、c-fos和c-jun蛋白的表达。结果:HCC组织中p42/44MAPK、p-Stat3、c-fos和c-jun蛋白的阳性率和阳性信号强度显著高于癌旁肝组织(P<0.01);在HCC和癌旁肝组织中p42/44MAPK和c-fos蛋白表达强度呈正相关;p-Stat3与c-jun蛋白亦呈正相关;但p42/44MAPK和p-Stat3信号强度之间均无明显相关性。结论:本资料提示Ras/Raf/MAPK和JAKs/Stat3信号级联异常可能在细胞恶性转化中均起重要作用;癌旁组织中呈p42/44MAPK和p-Stat3阳性的肝细胞可能是具有恶性潜能的癌前细胞群,推测MAPK和Stat3激活可能是HCC发生的早期事件。     

信号传导子及转录激活子3、Nanog基因在食管癌组织中的表达及其临床意义

目的:探讨信号传导子及转录激活子3（STAT3）、Nanog基因在食管癌组织中的表达及其临床意义。方法:收集本院收治的100例行手术切除的食管癌患者为研究对象。采用免疫组织化学法、Western blot法检测癌组织、癌旁组织中STAT3、Nanog的表达,记录患者临床病理参数并随访。统计分析STAT3、Nanog表达与患者临床病理参数的关系及对患者预后的影响。结果:免疫组化结果显示,STAT3、Nanog蛋白均主要表达于食管癌细胞的胞核及胞质,在癌旁组织中也有少量表达。STAT3在癌组织中的阳性率（56.0%,56/100）显著高于癌旁组织（30.0%,30/100）;Nanog在癌组织中的阳性率（74.0%,74/100）也明显高于癌旁组织（18.0%,18/100）。肿瘤分化程度、浸润深度、淋巴结转移、远处转移是影响患者STAT3阳性表达的独立性危险因素,且分化程度越低、TNM分期越晚,STAT3阳性率越高。肿瘤分化程度、淋巴结转移、远处转移是影响患者Nanog阳性表达的独立性危险因素,且分化程度越低、N分期、M分期越晚,Nanog阳性率越高。Western blot检测结果显示,STAT3、Nanog的分子量分别为88 kDa、66 kDa,且在癌组织内的表达强度显著高于癌旁组织。随访时间截止至2017年11月30日,全组患者随访3～46个月,中位随访时间12.5个月。STAT3（＋）与STAT3（-）患者的中位生存时间分别为9.5个月、17.8个月,差异具有统计学意义（χ2=16.33,P=0.000）;Nanog（＋）与Nanog（-）患者的中位生存时间分别为7.8个月、16.6个月,差异具有统计学意义（χ2=17.93,P=0.000）。结论:STAT3、Nanog在食管癌患者中阳性率较高,与肿瘤分化程度、TNM分期有一定的关系。与阴性患者相比,STAT3、Nanog阳性表达患者的中位生存时间明显较短,可作为判断患者预后的潜在因子。     

不同Stat6表型乳腺癌细胞IL-4/Stat6信号通路调节基因表达的研究

目的:探讨不同乳腺癌细胞株Stat6活化分型的可行性及IL-4的作用机制.方法:流式细胞仪测定不同Stat6表型细胞株ZR-75-1和BT-20的早期凋亡率;应用Affymetrix基因芯片测定IL-4刺激前后的基因表达谱变化.结果:Stat6null表型细胞与Stat6high相比早期凋亡增加(40%vs 12%);在Star6null细胞株有2 193个基因/转录产物表达升高,而Stat6high细胞株中2 600个基因/转录产物表达升高,且Stat6high细胞和Stat6null细胞中与凋亡和转移相关的基因表达谱明显不同;但不论在Stat6high还是Stat6null细胞株,IL-4均上调CCL26、SOCS1、CISH、EGLN3和SIDT1基因,而下调DUSP1、FOS和FOSB基因.结论:在乳腺癌细胞中,IL-4可能像在免疫细胞中一样,通过Stat6或非Stat6途径而发挥功能.     

miR-29a对人胃癌细胞增殖、迁移的影响及其机制研究

目的：探讨微小RNA-29a（miR-29a）对人胃癌细胞增殖、迁移的影响及其机制。方法：胃癌SGC-7901细胞随机分为miR-29a转染组、质粒对照组、空白对照组、信号转导子与转录激活子3（STAT3）抑制组。miR-29a转染组、质粒对照组采用脂质体转染法分别将has-miR-29a mimics质粒、siRNA对照质粒转染至人胃癌SGC-7901细胞,STAT3抑制组细胞加入STAT3抑制剂溶液,空白对照组不做处理。实时荧光定量聚合酶链反应（qPCR）和Western blot法检测转染后细胞中miR-29a、血管内皮生长因子（VEGF）、STAT3、细胞周期蛋白D1（cyclin D1）mRNA和蛋白的表达情况;MTT、划痕实验分别检测细胞增殖和迁移情况。结果：qPCR和Western blot实验结果显示,与空白对照组和质粒对照组比较,miR-29a转染组的miR-29a相对表达水平升高,VEGF、cyclin D1 mRNA及蛋白相对表达水平与p-STAT3/STAT3比值均下降（P < 0.01）。MTT实验与划痕实验结果显示,与空白对照组和质粒对照组比较,miR-29a转染组细胞在培养24、48、72 h的细胞相对增殖率及迁移率降低（P < 0.01）。与空白对照组比较,STAT3抑制组细胞的cyclin D1 mRNA及蛋白相对表达水平、p-STAT3/STAT3比值均降低,细胞相对增殖率与迁移率降低（P < 0.01）。结论：miR-29a能降低VEGF mRNA、蛋白的表达,抑制人胃癌细胞增殖和迁移,其机制可能与下调p-STAT3及cyclin D1的表达有关。     

miR-29a对人胃癌细胞增殖、迁移的影响及其机制研究

目的：探讨微小RNA-29a（miR-29a）对人胃癌细胞增殖、迁移的影响及其机制。方法：胃癌SGC-7901细胞随机分为miR-29a转染组、质粒对照组、空白对照组、信号转导子与转录激活子3（STAT3）抑制组。miR-29a转染组、质粒对照组采用脂质体转染法分别将has-miR-29a mimics质粒、siRNA对照质粒转染至人胃癌SGC-7901细胞，STAT3抑制组细胞加入STAT3抑制剂溶液，空白对照组不做处理。实时荧光定量聚合酶链反应（qPCR）和Western blot法检测转染后细胞中miR-29a、血管内皮生长因子（VEGF）、STAT3、细胞周期蛋白D1（cyclin D1）mRNA和蛋白的表达情况；MTT、划痕实验分别检测细胞增殖和迁移情况。结果：qPCR和Western blot实验结果显示，与空白对照组和质粒对照组比较，miR-29a转染组的miR-29a相对表达水平升高，VEGF、cyclin D1 mRNA及蛋白相对表达水平与p-STAT3/STAT3比值均下降（P < 0.01）。MTT实验与划痕实验结果显示，与空白对照组和质粒对照组比较，miR-29a转染组细胞在培养24、48、72 h的细胞相对增殖率及迁移率降低（P < 0.01）。与空白对照组比较，STAT3抑制组细胞的cyclin D1 mRNA及蛋白相对表达水平、p-STAT3/STAT3比值均降低，细胞相对增殖率与迁移率降低（P < 0.01）。结论：miR-29a能降低VEGF mRNA、蛋白的表达，抑制人胃癌细胞增殖和迁移，其机制可能与下调p-STAT3及cyclin D1的表达有关。     

STAT3在鼻咽癌中的表达特征及其与bcl—2和LMP1表达的关系

目的：探讨鼻咽癌中信号传导和转录激活子3(sTAT3)的表达特征及其与bcl-2和EB病毒潜在膜蛋白1(LMP1)表达的关系。方法：采用原位杂交和免疫组化法分别检测62例鼻咽癌组织中EB病毒EBER1的表达和STAT3、bcl-2和LMP1蛋白的表达。结果：鼻咽癌中EBER1阳性率为100．0％(62／62)；LMP1阳性率为61．3％(38／62)；STAT3和bcl-2阳性癌细胞占癌细胞总数的百分率跨度分别为5．0％～95．0％和0～100．0％。STAT3与bcl-2表达呈正相关，rs=0．444，P=0．000。STAT3与LMP1表达无显著相关性。结论：鼻咽癌细胞中STAT3呈持续表达状态(即异常激活状态)。STAT3的异常激活可能通过上调bcl-2这一抗凋亡基因的表达，从而延长了鼻咽癌细胞的生存时间。     

Inhibition of gp130 signaling in breast cancer blocks constitutive activation of Stat3 and inhibits in vivo malignancy

The cytokine receptor gp130 is the common signaling subunit of receptors used by the interleukin (IL)-6 cytokine family. gp130 is widely expressed in breast cancer cell lines and primary tumors. The role of gp130 in breast cancer in vivo is unknown. To study the effect of gp130 inhibition in breast cancer, endogenous gp130 signaling in breast cancer cell lines was blocked with a dominant-negative gp130 protein (DN gp130). DN gp130 inhibited constitutive Stat3 activation in breast cancer cells. Both gp130 and epidermal growth factor receptor (EGFR) have been implicated in constitutive Stat3 activation in breast cancer. There are known physical and functional interactions between gp130 and EGFR. Consistent with this, we show that DN gp130 inhibits signaling downstream of the EGFR in breast cancer cells. The effect of DN gp130 on breast cancer in vivo was assessed with an orthotopic nude mouse model. DN gp130 MDA-231 cells had markedly decreased engraftment, size, and metastasis compared with control cells. These results are particularly striking considering that DN gp130-expressing breast cancer cells grow faster in vitro. We hypothesized that DN gp130 expression results in inhibition of invasion and metastasis in vivo. Marked angiogenesis was present in tumors from control animals and was absent in tumors from DN gp130 animals. We additionally show that tissue inhibitor of metalloproteinase-3, an inhibitor of tumor invasion and angiogenesis, is up-regulated in both MDA-231 DN gp130 cells and tumors. These results, in light of the availability of several potential pharmacological inhibitors of gp130, suggest novel approaches to breast cancer therapy.     

激活和抑制Stat 3信号途径对胰腺癌细胞侵袭能力的影响

目的:通过激活和阻断人胰腺癌细胞中的Stat3信号转导通路,观察细胞株侵袭能力的变化并探讨其作用机制.方法:采用IL-6处理人胰腺癌细胞Capan-2,AG490处理人胰腺癌细胞SW1990后,MTT法检测细胞的增殖状态,免疫细胞化学法和Western 印迹法检测p-Stat3的表达,实时荧光定量PCR(real-time fluorogentic quantitative PCR, RFQ-PCR)和Western 印迹法检测血管内皮生长因子(vascular endothelial growth factor,VEGF)、基质金属蛋白酶-2(matrix metalloproteinase 2,MMP-2) mRNA及其蛋白的表达,体外侵袭实验检测细胞的侵袭能力.结果:IL-6可促进Capan-2细胞的增殖能力提高(P<0.05),p-Stat3的表达增强,VEGF和MMP-2 mRNA和蛋白表达明显升高(P<0.05),细胞侵袭能力增强.AG490可抑制SW1990细胞株的增殖(P<0.05),p-Stat3的表达下降,VEGF和MMP-2 mRNA和蛋白表达明显下降(P<0.05),侵袭能力减弱.结论:Stat3信号转导通路在胰腺癌侵袭过程中起着重要作用,以Stat3信号转导通路为靶点的基因治疗可能为胰腺癌治疗提供新的方向.     

IL-6/STAT3信号传导通路及其在肿瘤靶向治疗中的作用

白细胞介素-6(IL-6)与肿瘤患者的分期、预后、转归以及对化疗药物的敏感性有关,且在患者的肿瘤组织及血清中常呈过表达.IL-6主要通过介导信号转换和转录激活因子3(STAT3)信号传导通路(IL-6/STAT3信号传导通路)来调节肿瘤细胞的增殖和分化.因此,IL-6/STAT3信号传导通路的阻断,对肿瘤具有潜在治疗意...     

Roles of activated Src and Stat3 signaling in melanoma tumor cell growth

Activation of protein tyrosine kinases is prevalent in human cancers and previous studies have demonstrated that Stat3 signaling is a point of convergence for many of these tyrosine kinases. Moreover, a critical role for constitutive activation of Stat3 in tumor cell proliferation and survival has been established in diverse cancers. However, the oncogenic signaling pathways in melanoma cells remain to be fully defined. In this study, we demonstrate that Stat3 is constitutively activated in a majority of human melanoma cell lines and tumor specimens examined. Blocking Src tyrosine kinase activity, but not EGF receptor or JAK family kinases, leads to inhibition of Stat3 signaling in melanoma cell lines. Consistent with a role of Src in the pathogenesis of melanoma, we show that c-Src tyrosine kinase is activated in melanoma cell lines. Significantly, melanoma cells undergo apoptosis when either Src kinase activity or Stat3 signaling is inhibited. Blockade of Src or Stat3 is also accompanied by down-regulation of expression of the anti-apoptotic genes, Bcl-x(L) and Mcl-1. These findings demonstrate that Src-activated Stat3 signaling is important for the growth and survival of melanoma tumor cells.     

Requirement of Stat3 signaling for HGF/SF-Met mediated tumorigenesis.

Hepatocyte Growth Factor/Scatter Factor (HGF/SF) mediates a wide variety of cellular responses by acting through the Met tyrosine kinase receptor. Inappropriate expression of HGF/SF and/or Met has been found in most types of solid tumors and is often associated with poor prognosis. Importantly, constitutional and sporadic activating mutations in Met have been discovered in human papillary renal carcinomas and other cancers, while autocrine and paracrine signaling of this receptor/ligand pair has been shown to contribute to tumorigenesis and metastasis. Numerous downstream signaling molecules have been implicated in HGF/SF-Met mediated tumorigenesis and metastasis. Stat3 is a downstream signaling molecule activated by HGF/SF-Met signaling, and is reported to contribute to cell transformation induced by a diverse set of oncoproteins. Stat3 is constitutively activated in many primary tumors and tumor cell lines, suggesting that signaling by this molecule may be important for cell transformation. To address whether Stat3 is required for HGF/SF-Met mediated tumorigenesis and metastasis, we introduced a dominant-negative form of Stat3, Stat3beta into the human leiomyosarcoma cell line SK-LMS-1. We found that Stat3beta has no effect on the transformed morphology, proliferation, invasion or branching morphogenesis in vitro. By contrast, expression of Stat3beta affected HGF/SF-Met mediated anchorage-independent colony formation and prevented tumorigenic growth in athymic nu/nu mice. Thus, Met signaling through Stat3 provides an essential function for tumorigenic growth, which is manifested in vitro by loss of anchorage-independent growth.