吲哚美辛对CML细胞增殖抑制效应与STAT信号转导途径抑制相关

本研究的目的是观察吲哚美辛作用下慢性粒细胞白血病(CML)细胞增殖抑制过程中JAK2、STAT1和STAT5蛋白质表达水平的变化及细胞内分布，揭示吲哚美辛抑制CML细胞增殖的分子机制。采用MTT及台盼蓝拒染法检测吲哚美辛对CML细胞的增殖抑制作用，用Western blot分析CML细胞JAK2、STAT1和STAT5蛋白质表达，用间接免疫荧光技术观察STAT1和STAT5在吲哚美辛干预的CML细胞中的定位及变化，结果表明：400μmol／L浓度的吲哚美辛能明显抑制CML细胞增殖及STAT1、STAT5蛋白质表达，但对JAK2蛋白无影响；STAT1和STAT5主要分布于细胞胞浆中。结论：吲哚美辛可抑制CML细胞增殖，其机制可能与药物下调STAT1、STAT5蛋白质表达或与阻断细胞生长信号传导有关。     

Acylglycerol kinase augments JAK2/STAT3 signaling in esophageal squamous cells

JAK2 activity is tightly controlled through a self-inhibitory effect via its JAK homology domain 2 (JH2), which restricts the strength and duration of JAK2/STAT3 signaling under physiological conditions. Although multiple mutations within JAK2, which abrogate the function of JH2 and sustain JAK2 activation, are widely observed in hematological malignancies, comparable mutations have not been detected in solid tumors. How solid tumor cells override the autoinhibitory effect of the JH2 domain to maintain constitutive activation of JAK2/STAT3 signaling remains puzzling. Herein, we demonstrate that AGK directly interacted with the JH2 domain to relieve inhibition of JAK2 and activate JAK2/STAT3 signaling. Overexpression of AGK sustained constitutive JAK2/STAT3 activation, consequently promoting the cancer stem cell population and augmenting the tumorigenicity of esophageal squamous cell carcinoma (ESCC) cells both in vivo and in vitro. Furthermore, AGK levels significantly correlated with increased STAT3 phosphorylation, poorer disease-free survival, and shorter overall survival in primary ESCC. More importantly, AGK expression was significantly correlated with JAK2/STAT3 hyperactivation in ESCC, as well as in lung and breast cancer. These findings uncover a mechanism for constitutive activation of JAK2/STAT3 signaling in solid tumors and may represent a prognostic biomarker and therapeutic target.     

PP2A-activating drugs selectively eradicate TKI-resistant chronic myeloid leukemic stem cells

The success of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) depends on the requirement for BCR-ABL1 kinase activity in CML progenitors. However, CML quiescent HSCs are TKI resistant and represent a BCR-ABL1 kinase–independent disease reservoir. Here we have shown that persistence of leukemic HSCs in BM requires inhibition of the tumor suppressor protein phosphatase 2A (PP2A) and expression — but not activity — of the BCR-ABL1 oncogene. Examination of HSCs from CML patients and healthy individuals revealed that PP2A activity was suppressed in CML compared with normal HSCs. TKI-resistant CML quiescent HSCs showed increased levels of BCR-ABL1, but very low kinase activity. BCR-ABL1 expression, but not kinase function, was required for recruitment of JAK2, activation of a JAK2/β-catenin survival/self-renewal pathway, and inhibition of PP2A. PP2A-activating drugs (PADs) markedly reduced survival and self-renewal of CML quiescent HSCs, but not normal quiescent HSCs, through BCR-ABL1 kinase–independent and PP2A-mediated inhibition of JAK2 and β-catenin. This led to suppression of human leukemic, but not normal, HSC/progenitor survival in BM xenografts and interference with long-term maintenance of BCR-ABL1–positive HSCs in serial transplantation assays. Targeting the JAK2/PP2A/β-catenin network in quiescent HSCs with PADs (e.g., FTY720) has the potential to treat TKI-refractory CML and relieve lifelong patient dependence on TKIs.     

Gene Therapy of Mpl Deficiency: Challenging Balance Between Leukemia and Pancytopenia

Signaling of the thrombopoietin (THPO) receptor MPL is critical for the maintenance of hematopoietic stem cells (HSCs) and megakaryocytic differentiation. Inherited loss-of-function mutations of MPL cause severe thrombocytopenia and aplastic anemia, a syndrome called congenital amegakaryocytic thrombocytopenia (CAMT). With the aim to assess the toxicity of retroviral expression of Mpl as a basis for further development of a gene therapy for this disorder, we expressed Mpl in a murine bone marrow transplantation (BMT) model. Treated mice developed a profound yet transient elevation of multilineage hematopoiesis, which showed morphologic features of a chronic myeloproliferative disorder (CMPD) with progressive pancytopenia. Ten percent of mice (3/27) developed erythroleukemia, associated with insertional activation of Sfpi1 and Fli1. The majority of transplanted mice developed a progressive pancytopenia with histopathological features of a myelodysplastic syndrome (MDS)–like disorder. To avoid these adverse reactions, improved retroviral vectors were designed that mediate reduced and more physiological Mpl expression. Self-inactivating γ-retroviral vectors were constructed that expressed Mpl from the phosphoglycerate kinase (PGK) or the murine Mpl promoter. Mice that received BM cells expressing Mpl from the Mpl promoter were free of any previously observed adverse reactions.     

Targeting an IKBKE cytokine network impairs triple-negative breast cancer growth

Triple-negative breast cancers (TNBCs) are a heterogeneous set of cancers that are defined by the absence of hormone receptor expression and HER2 amplification. Here, we found that inducible IκB kinase–related (IKK-related) kinase IKBKE expression and JAK/STAT pathway activation compose a cytokine signaling network in the immune-activated subset of TNBC. We found that treatment of cultured IKBKE-driven breast cancer cells with CYT387, a potent inhibitor of TBK1/IKBKE and JAK signaling, impairs proliferation, while inhibition of JAK alone does not. CYT387 treatment inhibited activation of both NF-κB and STAT and disrupted expression of the protumorigenic cytokines CCL5 and IL-6 in these IKBKE-driven breast cancer cells. Moreover, in 3D culture models, the addition of CCL5 and IL-6 to the media not only promoted tumor spheroid dispersal but also stimulated proliferation and migration of endothelial cells. Interruption of cytokine signaling by CYT387 in vivo impaired the growth of an IKBKE-driven TNBC cell line and patient-derived xenografts (PDXs). A combination of CYT387 therapy with a MEK inhibitor was particularly effective, abrogating tumor growth and angiogenesis in an aggressive PDX model of TNBC. Together, these findings reveal that IKBKE-associated cytokine signaling promotes tumorigenicity of immune-driven TNBC and identify a potential therapeutic strategy using clinically available compounds.     

Lnk constrains myeloproliferative diseases in mice

Hematopoietic stem and progenitor cell (HSPC) expansion is regulated by intrinsic signaling pathways activated by cytokines. The intracellular kinase JAK2 plays an essential role in cytokine signaling, and activating mutations in JAK2 are found in a number of hematologic malignancies. We previously demonstrated that lymphocyte adaptor protein (Lnk, also known as Sh2b3) binds JAK2 and attenuates its activity, thereby limiting HSPC expansion. Here we show that loss of Lnk accelerates and exacerbates oncogenic JAK2-induced myeloproliferative diseases (MPDs) in mice. Specifically, Lnk deficiency enhanced cytokine-independent JAK/STAT signaling and augmented the ability of oncogenic JAK2 to expand myeloid progenitors in vitro and in vivo. An activated form of JAK2, unable to bind Lnk, caused greater myeloid expansion than activated JAK2 alone and accelerated myelofibrosis, indicating that Lnk directly inhibits oncogenic JAK2 in constraining MPD development. In addition, Lnk deficiency cooperated with the BCR/ABL oncogene, the product of which does not directly interact with or depend on JAK2 or Lnk, in chronic myeloid leukemia (CML) development, suggesting that Lnk also acts through endogenous pathways to constrain HSPCs. Consistent with this idea, aged Lnk^–/– mice spontaneously developed a CML-like MPD. Taken together, our data establish Lnk as a bona fide suppressor of MPD in mice and raise the possibility that Lnk dysfunction contributes to the development of hematologic malignancies in humans.     

MiR-467b调控JAK/STAT信号通路在脂多糖诱导ATDC5细胞增殖及炎症反应中的作用

目的:探讨miR-467b调控JAK/STAT信号通路在脂多糖(lipopolysaccharide,LPS)诱导ATDC5细胞增殖及炎症反应中的作用。方法:将ATDC5细胞分为4组:对照组、LPS组、NC mimics组、miR-467b mimics组。于转染培养48 h后收集细胞并进行后续实验:采用ELISA检测各组细胞TNF-α、IL-1β水平;采用qRT-PCR法检测各组细胞miR-467b的表达水平;采用MTT法检测各组细胞的增殖能力;采用蛋白质印迹和qRT-PCR法检测各组细胞JAK/STAT信号通路相关基因的蛋白质及mRNA表达水平。结果:与对照组相比,LPS组和NC mimics组ATDC5细胞TNF-α、IL-1β的表达水平均显著升高、miR-467b的表达水平显著降低(P<0.05);MTT实验结果表明:LPS组在24、48、72 h的吸光度值显著降低(P<0.05)。蛋白质印迹结果发现:与对照组相比,LPS组和NC mimics组ATDC5细胞STAT1、STAT3、JAK2、p-STAT1、p-STAT3、p-JAK2蛋白表达水平及STAT1、STAT3、JAK2 mRNA表达水平均显著升高,差异具有统计学意义(P<0.05)。与NC mimics组相比,miR-467b mimics组TNF-α、IL-1β的表达水平均显著降低而miR-467b的表达水平显著升高(P<0.05);过表达miR-467b后,细胞在24、48、72 h的吸光度值显著升高(P<0.05),而STAT1、STAT3、JAK2、p-STAT1、p-STAT3、p-JAK2蛋白表达水平及STAT1、STAT3、JAK2 mRNA表达水平均显著降低(P<0.05)。结论:LPS刺激ATDC5细胞后可通过激活JAK/STAT3信号通路引起细胞炎性损伤,过表达miR-467b后可抑制JAK/STAT3信号通路的活化,降低ATDC5细胞的炎症水平。     

针灸对阿尔茨海默病大鼠的治疗作用及相关信号通路研究

目的 研究针灸对阿尔茨海默病大鼠的治疗作用及相关信号通路。方法 取40只SD大鼠,随机分为对照组(正常大鼠,不处理)、假手术组(大鼠双侧海马CA1区注射等量生理盐水)、模型组(建立阿尔茨海默病模型)、干预组(建立阿尔茨海默病模型+针灸),每组各10只。取各组大鼠脑组织,经苏木精-伊红染色行病理学检查;比较各组大鼠脑皮层区Janus激酶2(JAK2)、信号转导子和转录激活子3(STAT3)和炎性细胞因子白细胞介素1 (IL-1)、白细胞介素6(IL-6)阳性细胞数比率;采用免疫印迹法检测大鼠脑皮层区JAK2和STAT3蛋白表达情况。结果 病理学检查提示,模型组和干预组大鼠均出现不同程度的病理改变,且干预组的病理损伤程度明显轻于模型组。模型组、干预组大鼠脑皮层区JAK2、STAT3、IL-1和IL-6阳性细胞数比率较对照组、假手术组均明显升高(P <0. 01);干预组大鼠脑皮层区JAK2、STAT3、IL-1和IL-6阳性细胞数比率较模型组明显下降(P <0. 01)。免疫印迹法检测可知,相比对照组、假手术组,模型组、干预组大鼠脑皮层区JAK2和STAT3蛋白表达水平均明显升高(P <0. 01);相比模型组,干预组大鼠脑皮层区JAK2和STAT3蛋白表达水平均明显下降(P <0. 01)。结论 针灸治疗可有效减轻阿尔茨海默病大鼠脑损伤,其原因可能在于针灸治疗可下调JAK2和STAT3蛋白表达,阻滞JAK2/STAT3信号通路的异常活化,抑制炎性细胞因子的表达,从而可抑制慢性炎症反应的进展,减轻病情程度,起到良好的治疗作用。     

雷公藤内酯醇抑制小鼠肾小球系膜细胞表达CXCL10的实验研究

目的探讨雷公藤内酯醇(triptolide,TPL)对γ干扰素(interferon-γ,IFN-γ)诱导的小鼠肾小球系膜细胞(SV40MES13)表达趋化因子CXCL10 m RNA的影响及其可能机制。方法将对数生长期SV40MES13随机分为空白组、刺激组、干预组,用不同浓度的IFN-γ(0U/ml~2000U/ml)刺激细胞不同时间(0h~48h)后,观察细胞表达CXCL10 m RNA的变化;用CCK-8法检测不同浓度(2ng/ml~20ng/ml)TPL对SV40MES13生存率的影响,选用细胞生存率大于90%的TPL用于后续实验,观察TPL对SV40MES13表达CXCL10 m RNA的影响;选用JAK/STAT信号通路特异性抑制剂AG490干预细胞,探讨IFN-γ是否通过JAK/STAT信号通路诱导CXCL10表达;收集以上细胞,用Real-Time PCR技术检测各组CXCL10 m RNA表达水平。结果 IFN-γ能诱导SV40MES13表达CXCL10 m RNA,并呈时间、剂量依赖性;AG490具有抑制IFN-γ诱导的SV40MES13表达CXCL10 m RNA;TPL具有抑制IFN-γ诱导的SV40MES13表达CXCL10 m RNA的作用。结论 IFN-γ可能通过激活JAK/STAT信号通路,诱导SV40MES13表达CXCL10 m RNA;TPL具有抑制IFN-γ诱导的SV40MES13表达CXCL10的作用。     

IL-33 signaling contributes to the pathogenesis of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are characterized by the clonal expansion of one or more myeloid cell lineage. In most cases, proliferation of the malignant clone is ascribed to defined genetic alterations. MPNs are also associated with aberrant expression and activity of multiple cytokines; however, the mechanisms by which these cytokines contribute to disease pathogenesis are poorly understood. Here, we reveal a non-redundant role for steady-state IL-33 in supporting dysregulated myelopoiesis in a murine model of MPN. Genetic ablation of the IL-33 signaling pathway was sufficient and necessary to restore normal hematopoiesis and abrogate MPN-like disease in animals lacking the inositol phosphatase SHIP. Stromal cell–derived IL-33 stimulated the secretion of cytokines and growth factors by myeloid and non-hematopoietic cells of the BM, resulting in myeloproliferation in SHIP-deficient animals. Additionally, in the transgenic JAK2^V617F model, the onset of MPN was delayed in animals lacking IL-33 in radio-resistant cells. In human BM, we detected increased numbers of IL-33–expressing cells, specifically in biopsies from MPN patients. Exogenous IL-33 promoted cytokine production and colony formation by primary CD34⁺ MPN stem/progenitor cells from patients. Moreover, IL-33 improved the survival of JAK2^V617F-positive cell lines. Together, these data indicate a central role for IL-33 signaling in the pathogenesis of MPNs.     

血小板源性生长因子-DD对肾小球系膜细胞JAK/STAT信号途径的影响

目的 探讨血小板源性生长因子-DD(PDGF-DD)对肾小球系膜细胞JAK/STAT信号途径的影响.方法 将实验用人肾小球系膜细胞分成对照组、PDGF-DD组(20μg/L)和PDGF-DD+AG490组(20 μg/L PDGF-DD+10 μmol/L AG490).采用免疫组化、蛋白印迹法、反转录聚合酶链反应等方法观察PDGF-DD对肾小球系膜细胞p-JAK2、STAT3、p-STAT3、SOCS1和SOCS3的蛋白及mRNA表达的影响.结果 PDGF-DD刺激后肾小球系膜细胞p-JAK2、STAT3、p-STAT3、SOCS1和SOCS3表达增强,AG490抑制上述蛋白的表达(P＜0.05或＜0.01).结论 PDGF-DD能够激活肾小球系膜细胞JAK/STAT信号途径,促进系膜细胞增殖.     

红细胞生成素受体介导的白血病细胞5纱增殖信号传导的研究

目的 检测白血病细胞系红细胞生成素受体（ＥｐｏＲ）的表达并阐明ＥｐｏＲ介导的白血病细胞系ＫＯＣＬ－３３增殖信号传导途径。方法 用生物系酰基化Ｅｐｏ及流式细胞仪检测白血 纱ＫＯＣＬ－３３细胞中几种信号传导蛋白 酷氨酸磷酸化。结果 （１）除Ｔ淋巴细胞系外,其余细胞纱ＥｐｏＲ表达均为阳性,阳性率为１８％～９９％,均值５２％。不同类型的细胞系ＥｐｏＲ阳性率的差异没有统计学意义。（２）９株细胞中７株细胞因受