用组织芯片技术研究JAK/Stat 5在肝癌组织中的表达及意义

目的研究肝癌中心癌组织、边缘癌组织和非癌肝硬化组织中JAK/Stat 5的表达特性及其意义。方法利用组织芯片技术和免疫组化SP法检测JAK/Stat 5在肝癌组织和非癌肝硬化组织的表达。结果中心癌组织JAK、Stat 5平均光密度值明显高于边缘癌组织(P<0.05);中心癌组织、边缘癌组织JAK、Stat 5表达率及表达强度明显高于非癌肝硬化组织;JAK、Stat 5表达阳性率与肝癌病理类型、分化程度无关。结论JAK、Stat 5表达与肝癌发生有密切关系,JAK/Stat 5表达异常可能在细胞恶性转化中起重要作用;边缘癌组织中JAK、Stat 5呈阳性表达的肝细胞可能是具有恶性潜能的癌前细胞群。     

Stat3与肿瘤的侵袭转移

Stat3是信号传导与转录激活因子家族(STATs)的成员之一,是一种重要的核转录因子,被细胞外细胞因子、生长因子等多肽类配体激活,作用于细胞核内特异的DNA片段,调控靶基因的转录,促进肿瘤细胞的增殖、血管形成、侵袭转移及免疫逃逸。诸多肿瘤细胞系及人的癌变组织中存在Stat3持续激活,因而Stat3有可能成为肿瘤分子治疗的新靶点。     

STAT3 入核分子机制的初步研究

为了研究Stat3入核的分子机制,将SV40大T抗原的经典核定位序列NLS(nuclear localization sequence)分别融合在Stat3-GFP分子和缺失突变体Dstat3-GFP的分子之间,构建Stat3-NLS-GFP和Dstat3-NLS-GFP融合分子。转染293T细胞,以NLS-GFP为阳性对照,通过激光共聚焦显微镜的观察融合分子的亚细胞位置,未经白介素-6刺激的Stat3-NLS-GFP和经白介素-6刺激的Stat3-GFP呈胞核分布,未经白介素-6刺激的Stat3-GFP和Dstat3-NLS-GFP呈胞浆分布,初步证明Stat3入核是由于获得了核定位序列。     

维生素E促进小鼠H-22移植瘤的作用及机制

[目的]利用H-22荷瘤小鼠研究维生素E(vitamin E,VE)对肿瘤发生发展的作用及机制。[方法]建立H-22小鼠荷瘤模型,计算肿瘤指数与肝脏指数,利用试剂盒检测血糖、血清低密度脂蛋白(low density lipoprotein,LDL)、总胆固醇(total cholesterol,TC)以及碱性磷酸酶(alkaline phosphatase,AKP)水平,利用苏木素-伊红染色与Real-time PCR检测VE对肿瘤发展和转移的作用及分子机制。[结果]肿瘤-VE组LDL水平、肿瘤组和肿瘤-VE组TC、AKP水平显著高于对照组(LDL,P 0.05; TC,P 0.01; AKP,P 0.001)。肿瘤组织中肿瘤-VE组小鼠p27K ip1、Stat3以及Cxcl12基因表达水平显著高于肿瘤组(p27~(Kip1)和Stat3,P 0.05,Cxcl12,P 0.01)。肝脏组织中肿瘤-VE组Jak2、Pigf及Cxcl12基因表达水平显著高于肿瘤组(P 0.05),且肿瘤组Jak2、Pigf及Cxcl12基因表达水平显著高于对照组(P 0.05)。[结论] VE处理的H-22荷瘤小鼠肿瘤组织中p27~(Kip1)、Stat3及Cxcl12表达水平显著升高,肝脏组织中Jak2、Pigf及Cxcl12表达水平显著升高,VE可能通过调控细胞周期、肿瘤转移及炎症相关基因的表达促进小鼠H-22肿瘤的发展。     

STAT3 入核分子机制的初步研究

为了研究Stat3入核的分子机制,将SV40大T 抗原的经典核定位序列NLS(nuclear localization sequence)分别融合在Stat3-GFP分子和缺失突变体Dstat3-GFP的分子之间,构建Stat3-NLS-GFP和Dstat3-NLS-GFP融合分子。转染293T细胞,以NLS-GFP为阳性对照,通过激光共聚焦显微镜的观察融合分子的亚细胞位置,未经白介素-6刺激的Stat3-NLS-GFP和经白介素-6刺激的Stat3-GFP呈胞核分布,未经白介素-6刺激的Stat3-GFP和Dstat3-NLS-GFP呈胞浆分布. 初步证明Stat3入核是由于获得了核定位序列。     

慢性炎症对肿瘤干细胞的调控

大量研究已证实肿瘤干细胞是肿瘤耐药、复发和转移的根源.慢性炎症与肿瘤的发生和发展密切相关,肿瘤炎性微环境中的IL-6、IL-8、EGF等炎性因子和生长因子激活了肿瘤干细胞内NF-κB/Stat3信号通路,维持肿瘤干细胞的自我更新能力,从而促进肿瘤的生长和转移.深入研究肿瘤炎性微环境对肿瘤干细胞的调控机制,可以使我们找到潜在的治疗靶点,为攻克肿瘤带来新的思路和手段.     

Targeting Stat3 induces senescence in tumor cells and elicits prophylactic and therapeutic immune responses against breast cancer growth mediated by NK cells and CD4+ T cells

Aberrant Stat3 activation and signaling contribute to malignant transformation by promoting cell cycle progression, inhibiting apoptosis, and mediating tumor immune evasion. Stat3 inhibition in tumor cells induces the expression of chemokines and proinflammatory cytokines, so we proposed to apply Stat3-inhibited breast cancer cells as a source of immunogens to induce an antitumor immune response. Studies were performed in two murine breast cancer models in which Stat3 is activated: progestin-dependent C4HD cells and 4T1 cells. We immunized BALB/c mice with irradiated cancer cells previously transfected with a dominant-negative Stat3 vector (Stat3Y705F) in either a prophylactic or a therapeutic manner. Prophylactic administration of breast cancer cells transfected with Stat3Y705F (Stat3Y705F-breast cancer cells) inhibited primary tumor growth compared with administration of empty vector-transfected cells in both models. In the 4T1 model, 50% of the challenged mice were tumor free, and the incidence of metastasis decreased by 90%. In vivo assays of C4HD tumors showed that the antitumor immune response involves the participation of CD4(+) T cells and cytotoxic NK cells. Therapeutic immunization with Stat3Y705F-breast cancer cells inhibited tumor growth, promoted tumor cell differentiation, and decreased metastasis. Furthermore, inhibition of Stat3 activation in breast cancer cells induced cellular senescence, contributing to their immunogenic phenotype. In this work, we provide preclinical proof of concept that ablating Stat3 signaling in breast cancer cells results in an effective immunotherapy against breast cancer growth and metastasis. Moreover, our findings showing that Stat3 inactivation results in induction of a cellular senescence program disclose a potential mechanism for immunotherapy research.