JAK2/STAT3 targeted therapy suppresses tumor invasion via disruption of the EGFRvIII/JAK2/STAT3 axis and associated focal adhesion in EGFRvIII-expressing glioblastoma

Background

As a commonly mutated form of the epidermal growth factor receptor, EGFRvIII strongly promotes glioblastoma (GBM) tumor invasion and progression, but the mechanisms underlying this promotion are not fully understood.

Methods

Through gene manipulation, we established EGFRvIII-, wild-type EGFR-, and vector-expressing GBM cells. We used cDNA microarrays, bioinformatics analysis, target-blocking migration and invasion assays, Western blotting, and an orthotopic U87MG GBM model to examine the phenotypic shifts and treatment effects of EGFRvIII expression in vitro and in vivo. Confocal imaging, co-immunoprecipitation, and siRNA assays detected the focal adhesion-associated complex and their relationships to the EGFRvIII/JAK2/STAT3 axis in GBM cells.

Results

The activation of JAK2/STAT3 signaling is vital for promoting migration and invasion in EGFRvIII-GBM cells. AG490 or WP1066, the JAK2/STAT3 inhibitors, specifically destroyed EGFRvIII/JAK2/STAT3-related focal adhesions and depleted the activation of EGFR/Akt/FAK and JAK2/STAT3 signaling, thereby abolishing the ability of EGFRvIII-expressing GBM cells to migrate and invade. Furthermore, the RNAi silencing of JAK2 in EGFRvIII-expressing GBM cells significantly attenuated their ability to migrate and invade; however, as a result of a potential EGFRvIII-JAK2-STAT3 activation loop, neither EGFR nor STAT3 knockdown yielded the same effects. Moreover, AG490 or JAK2 gene knockdown greatly suppressed tumor invasion and progression in the U87MG-EGFRvIII orthotopic models.

Conclusion

Taken together, our data demonstrate that JAK2/STAT3 signaling is essential for EGFRvIII-driven migration and invasion by promoting focal adhesion and stabilizing the EGFRvIII/JAK2/STAT3 axis. Targeting JAK2/STAT3 therapy, such as AG490, may have potential clinical implications for the tailored treatment of GBM patients bearing EGFRvIII-positive tumors.     

通讯作者：花宝金(1964-),男,黑龙江人,主任医师,博士研究生导师,研究方向: 中医药防治肿瘤复发转移。稿件联系人：蒋树龙,E-mail:jnsljiang@163.com。联系电话：13506383007。

【】　目的：总结JAK2/STAT3/SOCS3信号通路的作用特点及其与肿瘤转移潜能的最新研究进展。方法：应用PubMed及CNKI期刊全文数据库,以“JAK2、STAT3、SOCS3、肿瘤和信号转导”为关键词,检索2000-01~2013-10的相关文献,共检索到英文文献343篇,中文文献66篇。文献纳入标准：１)JAK2/STAT3/SOCS3信号通路的生物学特征及作用机制;２)JAK2/STAT3/SOCS3信号通路与肿瘤微环境的关系及其与肿瘤侵袭转移之间的内在联系。根据纳入标准符合条件的30篇。结果：JAK2/STAT3信号通路的激活参与了肿瘤发生、发展、侵袭和转移等多个环节;SOCS3负性调控JAK2/STAT3通路,从而抑制肿瘤的增殖和生长;STAT3信号通路的激活促成了肿瘤炎性微环境的形成,参与了肿瘤血管生成、上皮间质转化(EMT)、细胞外基质(ECM)降解等多个环节,在肿瘤的侵袭和转移过程中发挥重要作用。结论：JAK2/STAT3/SOCS3信号通路与肿瘤转移密切相关,针对JAK2/STAT3/SOCS3信号通路多靶点干预是肿瘤防治研究的一个新方向。     

Cyy260, a novel small molecule inhibitor,suppresses non-small cell lung cancer cell growth via JAK2/STAT3 pathway

Non-small cell lung cancer (NSCLC) is a malignant tumor that accounts for the most new cancer cases and cancer-related deaths worldwide, and the proliferation and metastasis of NSCLC are the main reasons for treatment failure and patient death. Traditional chemotherapeutic drugs have low selectivity, which can kill cancer cells and cause damage to normal cells at the same time. Therefore, it is particularly important to study therapies that target cancer cells and to find low-toxicity, high-efficiency anticancer drugs. Cyy260 is a novel small molecule inhibitor that we synthesized for the first time. Here, we investigated the in vitro and in vivo antitumor activities of Cyy260 and explored the underlying mechanisms in NSCLC. Cyy260 had a concentration- and time-dependent inhibitory effect on NSCLC cells, but it was less toxic to normal cells. Cyy260 regulated apoptosis through intracellular and extracellular apoptotic pathways. In addition, Cyy260 could also induce cell cycle arrest, thereby inhibiting cell proliferation. Further analysis of molecular mechanisms showed that the JAK2/STAT3 signaling pathway was involved in the antitumor effect mediated by Cyy260. Analysis of subcutaneously transplanted tumors in mice showed that Cyy260 suppressed tumor growth in vivo. Our results proved that Cyy260 is a novel inhibitor of the JAK2/STAT3 pathway thus may have potential in therapy of NSCLC and other cancers.     

A VEGFR1 antagonistic peptide inhibits tumor growth and metastasis through VEGFR1-PI3K-AKT signaling pathway inhibition

Angiogenesis is central to the growth of cancers and VEGFR-1/Flt-1 plays an important role during the neovascularization under pathological conditions. We previously founded a VEGFR1 antagonistic peptide, F56, by screening the phage peptide library. We showed that DHFR-F56 chimeric protein displayed anti-tumor activity and inhibited angiogenesis, however the anti-tumor activity of monomeric F56 and the mechanism remain unclear. In this study, we found that the F56 didn’t affect VEGF-A induced endothelial cell proliferation, but reduced migration and tube formation of endothelial cells. F56 also inhibited the sprout of rat aortic endothelial cells, the angiogenesis of chicken embryo chorioallantoic membrane as well as the generation of subintestinal vein vessels (SIV) in zebrafish embryos. We found that F56 inhibited VEGF-induced phosphorylation of VEGFR1, as well as the phosphorylation of the downstream of PI3K-AKT axis. However, F56 had no effect on the phosphorylation of VEGFR2. Correlating with these effects, F56 inhibited xenograft growth of HT-29 and MGC-823 cells in BALB/c nude mice, and significantly suppressed the lung metastasis of B16 cells in C57BL/6 mice. Our study demonstrated that monomeric peptide F56 had a significant anti-tumor activity by inhibiting angiogenesis, and laid the foundation for its clinical application.     

Induction of metastatic potential by TrkB via activation of IL6/JAK2/STAT3 and PI3K/AKT signaling in breast cancer

In metastatic breast cancers, the acquisition of metastatic ability, which leads to clinically incurable disease and poor survival, has been associated with acquisition of epithelial-mesenchymal transition (EMT) program and self-renewing trait (CSCs) via activation of PI3K/AKT and IL6/JAK2/STAT3 signaling pathways. We found that TrkB is a key regulator of PI3K/AKT and JAK/STAT signal pathway-mediated tumor metastasis and EMT program. Here, we demonstrated that TrkB activates AKT by directly binding to c-Src, leading to increased proliferation. Also, TrkB increases Twist-1 and Twist-2 expression through activation of JAK2/STAT3 by inducing c-Src-JAK2 complex formation. Furthermore, TrkB in the absence of c-Src binds directly to JAK2 and inhibits SOCS3-mediated JAK2 degradation, resulting in increased total JAK2 and STAT3 levels, which subsequently leads to JAK2/STAT3 activation and Twist-1 upregulation. Additionally, activation of the JAK2/STAT3 pathway via induction of IL-6 secretion by TrkB enables induction of activation of the EMT program via induction of STAT3 nuclear translocation. These observations suggest that TrkB is a promising target for future intervention strategies to prevent tumor metastasis, EMT program and self-renewing trait in breast cancer.     

Icaritin suppresses multiple myeloma,by inhibiting IL-6/JAK2/STAT3

Icaritin is an active prenylflavonoid derived from Epimedium genus, a traditional Chinese medicine. Icaritin has a wide range of pharmacological and biological activities, including cardiovascular function improvement, hormone regulation and antitumor activity. Here, we investigated the effect of icaritin on multiple myeloma (MM) in vitro and in vivo. Icaritin inhibited cell growth of MM cell line and primary MM cells. In contrast, icaritin had low or no cytotoxic effect on normal hematopoiesis. We also demonstrated that in MM xenograft mouse models, icaritin suppressed tumor growth and decreased serum IL-6 and IgE levels, but did not show adverse reactions such as body weight loss. The anti-MM activity of icaritin was mainly mediated by inhibiting IL-6/JAK2/STAT3 signaling. We suggest that icaritin can be further tested in clinical trials in MM.     

Norcantharidin inhibits tumor angiogenesis via blocking VEGFR2/MEK/ERK signaling pathways

Norcantharidin (NCTD), the demethylated form of Cantharidin, a reagent isolated from blister beetles, has been shown to be an anti‐tumor agent capable of inhibiting proliferation as well as inducing apoptosis in many cancer cell lines. However, little is known about the effect of NCTD in tumor angiogenesis. In this study, we demonstrated that NCTD inhibited vascular endothelial growth factor (VEGF)‐induced cell proliferation, migration, invasion, and capillary tube formation of primary human umbilical vein endothelial cells (HUVECs) in a dose‐dependent manner. Furthermore, we showed NCTD inhibited tumor growth and angiogenesis of colon cancer cells (LOVO) in vivo. We then mechanistically described that NCTD specifically abrogated the phosphorylation/activation of vascular endothelial growth factor receptor‐2 (VEGFR2)/MEK/ERK pathway kinases, with little effect on the phosphorylation of p38 MAPK and Akt, and on Cox‐2 expression. In summary, our results indicate that NCTD is a potential inhibitor of tumor angiogenesis by blocking VEGFR2/MEK/ERK signaling.     

柴胡疏肝散对早期肝纤维化大鼠JAK2/STAT3信号通路的影响

目的: 研究柴胡疏肝散对早期肝纤维化大鼠JAK2/STAT3信号通路的影响。方法: 以CCl₄诱导造模,将SD大鼠50只按随机数字表法分为正常组(腹腔注射橄榄油+蒸馏水灌胃),模型组(腹腔注射40% CCl₄橄榄油溶液,蒸馏水灌胃),柴胡疏肝散低、中、高剂量组(腹腔注射40% CCl₄橄榄油溶液,同时分别按生药3.5,6.3,12.6 g/kg灌胃)。柴胡疏肝散给药至第10周,观察大鼠大体形态,计算肝系数;全自动生化分析仪测定血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST),酶联免疫吸附法(ELISA)检测血清透明质酸(HA)、Ⅲ型前胶原(PCⅢ)、Ⅳ型胶原(Ⅳ-C)变化;HE染色观察各组大鼠肝脏纤维化程度;荧光定量PCR(qPCR)法检测肝组织中的JAK2、STAT3 mRNA表达;Western blot法检测肝组织中JAK2和STAT3蛋白表达。结果: 与正常组比较,模型组大鼠血清ALT、AST、HA、PCⅢ、Ⅳ-C的含量均明显升高(P<0.01),HE染色显示模型组大鼠肝细胞出现明显水肿、坏死、炎性细胞浸润。与模型组比较,柴胡疏肝散低、中、高剂量组能抑制肝细胞坏死、炎性细胞浸润,且血清中ALT、AST、HA、PCⅢ、Ⅳ-C水平均显著降低(P<0.05或P<0.01);柴胡疏肝散中、高剂量组大鼠的肝系数显著降低(P<0.05);柴胡疏肝散各剂量组不同程度抑制肝组织中JAK2、STAT3 mRNA及蛋白的表达(P<0.05或P<0.01)。结论: 柴胡疏肝散对早期肝纤维化大鼠的保护作用可能与抑制JAK2/STAT3信号通路相关。     

STAT3 表达与肿瘤血管生成及放射敏感性关系的研究进展*

信号转导和转录活化因子3（STAT3）属于STATs 家族中重要一员,广泛表达于不同类型的细胞和组织中,并参与细胞生长、增殖、凋亡、恶性转化等生理和病理过程的调控。近年来,STAT3 在肿瘤血管生成及放疗敏感性方面的研究日益增多。研究表明STAT3 活化后,一方面通过直接调控血管内皮生长因子（VEGF）表达促进血管生成进而产生放疗抗拒;另一方面STAT3 通过活化缺氧诱导因子- 1α（HIF-1α）间接促进血管生成产生放疗耐受。此外,STAT3 还可以直接或通过HIF-1α 间接调控细胞周期蛋白D 1（CyclinD1）表达,使细胞周期由G 1 期快速进入S 期,促进细胞增殖,且CyclinD1 与放疗敏感性相关。由此发现,STAT3 通过直接和间接两种途径在肿瘤血管生成及放疗抗拒方面发挥作用。本文拟对此方面的相关研究新进展作一综述。     

ST8SIA1 inhibits the proliferation,migration and invasion of bladder cancer cells by blocking the JAK/STAT signaling pathway

Bladder cancer (BLCA) is the most common malignant tumor of the urinary system, with distant metastasis of the tumor being the main cause of death. The identification of an effective biomarker may provide a novel direction for BLCA diagnosis and treatment. The aim of the present study was to screen the BLCA-related genes involved in sialyl transferase (ST) dysregulation and to investigate the functional mechanisms of α-2,8-ST1 (ST8SIA1) in BLCA cells. Data from The Cancer Genome Atlas and Gene Expression Profiling Interactive Analysis databases suggested that the mRNA expression levels of ST8SIA1 were decreased in BLCA tissues compared with normal tissues, which was also demonstrated using immunohistochemistry and western blot analysis. The expression levels of ST8SIA1 were negatively associated with the pathological grade and invasiveness of BLCA. Western blot analysis revealed that the expression levels of ST8SIA1 were lower in BLCA cell lines than in a normal urothelial cell line. CCK-8, flow cytometry, wound healing, colony formation and Transwell assays indicated that ST8SIA1 overexpression attenuated the proliferation, migration and invasion of T24 and 5637 BLCA cells. Further experiments revealed that ST8SIA1 could inhibit the phosphorylation of Janus kinase (JAK)2 and STAT3, as well as decrease the expression levels of JAK/STAT pathway-targeting signal molecules, including MMP2, proliferating cell nuclear antigen, cyclin D1 and Bcl2 in two BLCA cell lines. In conclusion, to the best of our knowledge, the present study was the first to indicate that the antitumor effect of ST8SIA1 in BLCA cells was mediated by the JAK/STAT signaling pathway, and the results provided a novel target for the diagnosis and treatment of BLCA.     

Oral squamous cell carcinoma cell-derived GM-CSF regulates PD-L1 expression in tumor-associated macrophages through the JAK2/STAT3 signaling pathway

Previous study reported that gastric cancer-derived granulocyte-macrophage colony-stimulating factor (GM-CSF) could mediate neutrophil activation and induce PD-L1 expression through JAK2/STAT3 signaling pathway. Moreover, this pathway in various cancers could also regulate PD-L1 expression of tumor cells. Therefore, our study aimed to investigate whether the JAK2/STAT3 pathway regulates PD-L1 expression in tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC), which can help us achieve further understanding of immune escape mechanisms in OSCC. We induced human monocytes THP-1 into M0, M1, and M2 macrophages, and applied them to common medium and tumor-conditioned medium, the latter was collected from two types of OSCC cell line. Western blot and RT-PCR were used to detect PD-L1 expression and activation of JAK2/STAT3 pathway in macrophages under various conditions. We found that GM-CSF in tumor-conditioned medium from OSCC cells increased PD-L1 expression in M0 macrophages in a time-dependent manner. Moreover, both GM-CSF neutralizing antibody and JAK2/STAT3 pathway inhibitor AG490 could inhibited its up-regulation. In the meantime, we confirmed that GM-CSF indeed acted through JAK2/STAT3 pathway by measuring phosphorylation of key proteins in this pathway. Therefore, we concluded that OSCC cell-derived GM-CSF was able to up-regulate PD-L1 expression in TAMs through JAK2/STAT3 signaling pathway.     

miR-874 functions as a tumor suppressor by inhibiting angiogenesis through STAT3/VEGF-A pathway in gastric cancer

MicroRNAs are endogenously expressed, small non-coding RNAs that regulate gene expression by targeting mRNAs for translational repression or degradation. Our previous studies indicated that miR-874 played a suppressive role in gastric cancer (GC) development and progression. However, the role of miR-874 in tumor angiogenesis and the mechanisms underlying its function in GC remained to be clarified. Here, gain- and loss-of-function assays demonstrated that miR-874 inhibited the tumor angiogenesis of GC cells in vitro and in vivo. Through reporter gene and western blot assays, STAT3 was shown to be a direct target of miR-874. Overexpression of STAT3 rescued the loss of tumor angiogenesis caused by miR-874. Conversely, the STAT3-shRNA attenuated the increased tumor angiogenesis caused by the miR-874-inhibitor. Furthermore, the levels of miR-874 were inversely correlated with those of STAT3 protein in GC tissues. Taken together, these findings indicate that down-regulation of miR-874 contributes to tumor angiogenesis through STAT3 in GC, highlighting the potential of miR-874 as a target for human GC therapy.     

PYCR1 knockdown inhibits the proliferation,migration, and invasion by affecting JAK/STAT signaling pathway in lung adenocarcinoma

Lung adenocarcinoma (LUAD), as a form of non-small cell lung cancer (NSCLC), is the most frequently diagnosed lung cancer worldwide. To date, a few biomarkers have been reported to provide valuable information in guiding LUAD treatment. The aim of our study was to explore the functional role of pyrroline-5-carboxylate reductase 1 (PYCR1) in LUAD. Based on Oncomine database, we found that PYCR1 was highly expressed in LUAD tissues. We also confirmed an abnormal increase of PYCR1 expression in LUAD cell lines and patients' tissues. Through Kaplan-Meier plotter database, we further studied the prognostic values of PYCR1. The outcomes indicated that overexpressed PYCR1 associated with poor prognosis among LUAD patients. To further study the function of PYCR1 in LUAD, cell counting kit-8, colony-forming, scratch wound healing, and Transwell assays were conducted. The results suggested that knockdown of PYCR1 curbed cell proliferation, migration, and invasion in LUAD cell lines. Subsequently, we identified 50 top genes positively and negatively correlated with PYCR1 in LUAD, and conducted biological pathway enrichment analysis of these genes. Among those enriched pathways, we selected JAK/STAT signaling pathway for further analysis. The results of Western blot assays revealed that PYCR1 knockdown significantly increased the expression of Bcl-2 and c-Myc, and the phosphorylation level of JAK2 and STAT3. Taken together, this study unearthed that PYCR1 knockdown could inhibit tumor growth and affect the JAK/STAT signaling pathway in LUAD. This study may contribute to a better understanding of PYCR1 in LUAD and provide a potential biomarker for cancer prognosis.     

Gastrin acting on the cholecystokinin2 receptor induces cyclooxygenase-2 expression through JAK2/STAT3/PI3K/Akt pathway in human gastric cancer cells

Gastrin, cholecystokinin2 receptor (CCK2R), and cyclooxygenase-2 (COX-2) have been implicated in the carcinogenesis and progression of gastric cancer. Our study demonstrated that antagonist or siRNA against CCK2R blocked amidated gastrin (G17)-induced activation of STAT3 and Akt in gastric cancer cell lines. G17-increased COX-2 expression and cell proliferation were effectively blocked by CCK2R antagonist and inhibitors of JAK2 and PI3K. In addition, knockdown of STAT3 expression significantly attenuated G17-induced PI3K/Akt activation, COX-2 expression, and cell proliferation. These results suggest that CCK2R-mediated COX-2 up-regulation via JAK2/STAT3/PI3K/Akt pathway is involved in the proliferative effect of G17 on human gastric cancer cells.     

虫草素抑制JAK2/STAT3通路减轻肺癌大鼠放射性免疫功能损伤

目的 探讨虫草素通过JAK2/STAT3信号通路对肺癌大鼠放射性治疗免疫功能损伤的抑制作用。方法 50只大鼠建立荷瘤模型,另设正常组（10只）。建模成功大鼠随机分为模型组、放疗组、虫草素组、激动剂组和激动剂+虫草素组,每组10只。比较各组大鼠瘤重、肿瘤体积、抑瘤率、IL-6、TNF-α、脾指数、胸腺指数、T淋巴细胞亚群数量、JAK2、p-JAK2、STAT3和p-STAT3蛋白表达水平。结果 与正常组比较,模型组IL-6、TNF-α、CD8+、p-JAK2、p-STAT3升高,脾指数、胸腺指数、CD4+、CD4+/CD8+降低（P<0.05）;与模型组比较,放疗组瘤重、肿瘤体积、脾指数、胸腺指数、CD4+、CD4+/CD8+降低,IL-6、TNF-α、CD8+、p-JAK2和p-STAT3升高（P<0.05）;与放疗组比较,虫草素组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3降低,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8+升高,激动剂组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3升高,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8 +降低（P<0.05）;与激动剂+虫草素组比较,虫草素组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3降低,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8+升高,激动剂组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3升高,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8+降低（P<0.05）。结论 虫草素可有效抑制肺癌大鼠放射性治疗免疫功能损伤,其机制可能通过抑制JAK2/STAT3信号通路蛋白表达发挥调控作用。