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bcl2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、bcl2和LMP1蛋白的表达。结果:鼻咽癌中EBER1阳性率为1000%(62/62);LMP1阳性率为613%(38/62);STAT3和bcl2阳性癌细胞占癌细胞总数的百分率跨度分别为50%~950%和0~1000%。STAT3与bcl2表达呈正相关,rs=0444,P=0000。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bcl2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。     

舒尼替尼体内诱导耐药鼻咽癌细胞表达NKG2DLs增强NK细胞的抑瘤作用

目的：探讨体内条件下舒尼替尼对耐药鼻咽癌CNE2/DDP细胞NKG2DLs（natural killer group 2 member D ligands)表达的诱导作用,及其对NK细胞抗肿瘤活性的影响。方法：建立ABCG2highCNE2/DDP和ABCG2lowCNE2/DDP细胞裸鼠皮下移植瘤模型,分如下8组：A、E组分别接种ABCG2high、ABCG2lowCNE2/DDP细胞,B、F组分别接种舒尼替尼处理的ABCG2high、ABCG2lowCNE2/DDP细胞,C、G组分别接种ABCG2high、ABCG2lowCNE2/DDP细胞后再输注NK细胞;D、H组接种舒尼替尼处理的ABCG2high、ABCG2lowCNE2/DDP细胞后再输注NK细胞。检测各组裸鼠成瘤时间、成瘤率、肿瘤体积和抑瘤率。免疫组织化学法检测移植瘤组织中NKG2DLs的表达。结果：A、B、C、D和E、F、G、H组肿瘤出现时间分别为(5.43±1.00)、(8.50±035)、(1110±1.25)、(13.56±1.23) d和 (9.00±1.00)、(12.30±0.78)、(14.50±0.50)、(17.25±0.77) d,其中舒尼替尼与NK细胞联合处理组（D 和H 组）成瘤时间最晚（P<0.01）。A、B、C、D和E、F、G、H组肿瘤质量分别为(2.63±089)、(1.00±003)、(065±0.08)、(0.21±0.27) g和(2.79±0.83)、(1.18±0.77)、(0.96±0.50)、(0.86±0.82) g,其中舒尼替尼与NK细胞联合处理组肿瘤质量最小（P<001）;舒尼替尼与NK细胞联合处理的D组和H组的抑瘤率分别为92%和69%。舒尼替尼上调移植瘤组织中NKG2DLs的表达,且ABCG2highCNE2/DDP细胞移植瘤中的NKG2DLs表达率高于ABCG2lowCNE2/DDP细胞。结论：舒尼替尼可在体内诱导CNE2/DDP移植瘤组织表达NKG2DLs,增强NK细胞的抗肿瘤作用。     

Interferon‐γ down‐regulates NKG2D ligand expression and impairs the NKG2D‐mediated cytolysis of MHC class I‐deficient melanoma by natural killer cells

NKG2D operates as an activating receptor on natural killer (NK) cells and costimulates the effector function of αβ CD8⁺ T cells. Ligands of NKG2D, the MHC class I chain‐related (MIC) and UL16 binding protein (ULBP) molecules, are expressed on a variety of human tumors, including melanoma. Recent studies in mice demonstrated that NKG2D mediates tumor immune surveillance, suggesting that antitumor immunity in humans could be enhanced by therapeutic manipulation of NKG2D ligand (NKG2DL) expression. However, signals and mechanisms regulating NKG2DL expression still need to be elucidated. Here, we asked whether the proinflammatory cytokine Interferon‐γ (IFN‐γ) affects NKG2DL expression in melanoma. Cell lines, established from MHC class I‐negative and ‐positive melanoma metastases, predominantly expressed MICA and ULBP2 molecules on their surface. Upon IFN‐γ treatment, expression of MICA, in some cases, also of ULBP2 decreased. Besides melanoma, this observation was made also for glioma cells. Down‐regulation of NKG2DL surface expression was dependent on the cytokine dose and the duration of treatment, but was neither due to an intracellular retention of the molecules nor to an increased shedding of ligands from the tumor cell surface. Instead, quantitative RT‐PCR revealed a decrease of MICA‐specific mRNA levels upon IFN‐γ treatment and siRNA experiments pointed to an involvement of STAT‐1 in this process. Importantly, IFN‐γ‐treated MHC class I‐negative melanoma cells were less susceptible to NKG2D‐mediated NK cell cytotoxicity. Our study suggests that IFN‐γ, by down‐regulating ligand expression, might facilitate escape of MHC class I‐negative melanoma cells from NKG2D‐mediated killing by NK cells. © 2008 Wiley‐Liss, Inc.     

AZD1480 delays tumor growth in a melanoma model while enhancing the suppressive activity of myeloid-derived suppressor cells

AZD1480 is a potent, competitive small-molecule inhibitor of JAK1/2 kinase which inhibits STAT3 phosphorylation and tumor growth. Here we investigated the effects of AZD1480 on the function of different immune cell populations in a melanoma model. When MO4 tumor-bearing mice were treated with AZD1480 we observed a strong inhibition of tumor growth as well as a prolonged survival. Moreover, a significant decrease in the percentage of myeloid-derived suppressor cells (MDSCs) was observed after treatment with AZD1480. However, AZD1480 enhanced the suppressive capacity of murine MDSCs while at the same time impairing the proliferative as well as the IFN-γ secretion capacity of murine T cells. The addition of AZD1480 to co-cultures of human MDSCs and T cells does not affect the suppressive activity of MDSCs but it does reduce the IFN-γ secretion and the proliferative capacity of T cells. We showed that although AZD1480 has the ability to delay the tumor growth of MO4 tumor-bearing mice, this drug has detrimental effects on several aspects of the immune system. These data indicate that systemic targeting of the JAK/STAT pathway by JAK1/2 inhibition can have divergent effects on tumor growth and anti-tumor immune responses.     

桦木酸通过抑制STAT3 的活化提高胰腺癌细胞对吉非替尼的敏感性

[摘要] 目的：探讨桦木酸（BEA）提高胰腺癌Panc-1、Miapaca-2 细胞对吉非替尼的敏感性及其潜在的作用机制。方法：细胞培养完成后,将对吉非替尼不敏感的Panc-1、Miapaca-2 细胞随机分为4 组：对照组、BEA组、吉非替尼组及BEA联合吉非替尼组,分别予以不处理、BEA、吉非替尼及BEA联合吉非替尼处理。MTS法检测BEA对2 种细胞的增敏效果,集落形成实验检测BEA协同吉非替尼的治疗效果,WB实验检测BEA对Panc-1 细胞凋亡相关蛋白的影响,流式细胞术检测BEA对Panc-1 细胞凋亡的影响,表面等离子体共振（SPR）实验验证信号转导子和转录激活子3（STAT3）和BEA的直接结合,分子对接和分子动力学模拟实验预测STAT3 和BEA的结合模式。结果：BEA协同增强Panc-1、Miapaca-2 细胞对吉非替尼的敏感性（P<0.05）,使其对两种细胞的IC50值均降低至原值的50%以下。吉非替尼联合BEA较单用吉非替尼或BEA促进Panc-1 细胞的凋亡以及凋亡相关蛋白cleaved-PARP和Bax 的表达,减少对凋亡抑制蛋白Bcl-2 的表达（均P<0.05 或P<0.01）。BEA对Panc-1 细胞中STAT3 的活化有剂量依赖性抑制作用（P<0.01）。BEA通过与STAT3 的Lys-591、Ser-613 形成氢键而稳定BEA与STAT3 的结合作用,同时BEA稳定在STAT3 的蛋白结合位点内,以此阻断STAT3 二聚发挥增敏作用。结论：联用BEA和吉非替尼显著抑制胰腺癌Panc-1、Miapaca-2 细胞的增殖并促进其凋亡,这种增敏作用可能是由BEA对STAT3 抑制作用所介导。     

胶质瘤细胞中IL-1RAP的作用及其与STAT3的关系

目的 研究白介素1受体辅助蛋白（IL-1RAP）在胶质瘤中的作用及其与转录活化因子3（STAT3）的关系。方法 构建IL-1RAP表达载体,转染胶质瘤细胞系U251,利用流式±细胞仪检测转染IL-1RAP对U251细胞周期及凋亡影响。利用免疫共沉淀钓取STAT3,检测转染IL-1RAP后STAT3的表达情况,并利用免疫荧光方法检测IL-1RAP与STAT3的共定位情况。结果 IL-1RAP蛋白定位于胶质瘤细胞核。与转染空质粒对照组相比,IL-1RAP有明显的促进肿瘤细胞凋亡[(52.10±5.51)% vs.(7.57± 0.54)%, P＜0.05]和周期阻滞作用[(68.22±1.96)% vs.(38.31±7.22)%, P＜0.05]。通过免疫共沉淀和共定位证实IL-1RAP和STAT3可以相互作用。结论 IL-1RAP有抑制胶质瘤细胞增殖、促进细胞凋亡的作用。IL-1RAP可能通过与STAT3相互作用进入细胞核发挥促进细胞凋亡和抑制细胞周期的作用。     

Increase of CIK cell efficacy by upregulating cell surface MICA and inhibition of NKG2D ligand shedding in multiple myeloma

Multiple myeloma, which is a monoclonal plasma cell malignancy, still remains incurable despite recent progress in our understanding of this disorder. Adoptive immunotherapy of multiple myeloma using cytokine‐induced killer cells is yielding promising results in clinical trials; however, some myeloma cells still evade immune surveillance by various unknown molecular mechanisms. This study aims at increasing the efficacy of cytokine‐induced killer cells in targeting this tumor, using selective small‐molecule inhibitors which increase and stabilize surface expression of the natural killer group 2, member D ligand, major histocompatibility complex class I polypeptide‐related sequence A (MICA) on myeloma cells. We treated 2 multiple myeloma cell lines—U266 and KMS‐12‐PE—with 3 drugs. One of these drugs (sodium butyrate) is a histone deacetylase inhibitor. Another drug which was used (matrix metalloproteinase inhibitor III) blocks ligand shedding while the third drug (phenylarsine oxide) obstructs surface ligand internalization. The effect of these drugs on cell viability was determined using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, surface ligand expression was examined using flow cytometry, and ligand shedding was assessed using enzyme‐linked immunosorbent assay. We demonstrated that cytokine‐induced killer cells have increased cytotoxicity against multiple myeloma cells after combined drug treatment than without drug pretreatment. We also established that this increased cytotoxicity was due to potent upregulation and stabilization of surface MICA on the surface of these tumor cell lines. Our study thus highlights further therapeutic options which could be used for the treatment of multiple myeloma patients.     

Multipotent mesenchymal stromal cells promote tumor growth in distinct colorectal cancer cells by a β1‐integrin‐dependent mechanism

Tumor–stroma interactions play an essential role in the biology of colorectal carcinoma (CRC). Multipotent mesenchymal stromal cells (MSC) may represent a pivotal part of the stroma in CRC, but little is known about the specific interaction of MSC with CRC cells derived from tumors with different mutational background. In previous studies we observed that MSC promote the xenograft growth of the CRC cell‐line DLD1. In the present study, we aimed to analyze the mechanisms of MSC‐promoted tumor growth using various in vitro and in vivo experimental models and CRC cells of different mutational status. MSC specifically interacted with distinct CRC cells and supported tumor seeding in xenografts. The MSC–CRC interaction facilitated three‐dimensional spheroid formation in CRC cells with dysfunctional E‐cadherin system. Stable knock‐downs revealed that the MSC‐facilitated spheroid formation depended on β1‐integrin in CRC cells. Specifically in α‐catenin‐deficient CRC cells this β1‐integrin‐dependent interaction resulted in a MSC‐mediated promotion of early tumor growth in vivo. Collagen I and other extracellular matrix compounds were pivotal for the functional MSC–CRC interaction. In conclusion, our data demonstrate a differential interaction of MSC with CRC cells of different mutational background. Our study is the first to show that MSC specifically compared to normal fibroblasts impact early xenograft growth of distinct α‐catenin deficient CRC cells possibly through secretion of extracellular matrix. This mechanism could serve as a future target for therapy and metastasis prevention.     

莱菔素通过阻断STAT3 信号通路杀伤三阴性乳腺癌细胞MDA-MB-468和MDA-MA-231

[摘要] 目的：探讨染色体区域维持因子1（CRM1）抑制剂莱菔素（LFS-01）通过抑制信号转导及转录激活因子3（STAT3）信号通路杀伤三阴性乳腺癌（TNBC）细胞的作用及其机制。方法：通过分子动力学模拟技术,验证LFS-01 是否可与CRM1 分子结构上的核输出信号（NES）口袋结合。通过CCK-8 法检测LFS-01 对4 种不同的乳腺癌细胞杀伤活力。用不同浓度的LFS-01 处理TNBC细胞MDA-MB-468 和MDA-MB-231,免疫荧光法检测CRM1 货物蛋白STAT3 以及带有NES序列的蛋白在细胞内定位的变化;WB检测LFS-01 对STAT-3 信号通路以及其下游蛋白表达的影响;WB、细胞免疫荧光和透射电镜法检测自噬的发生;通过流式细胞术检测药物对细胞周期和凋亡的影响。结果：分子动力学模拟结果表明,LFS-01 能够与CRM1 的NES口袋结合,显示其在结构上影响后者蛋白转运功能的可能性。LFS-01 能特异性杀伤TNBC 细胞MDA-MB-468 和MDA-MB-231。10 μmol/L LFS-01 处理后TNBC细胞中STAT3 和带有NES标签的蛋白均被阻滞于细胞核中,而在对照组中这些蛋白均匀分布在细胞质中。随着LFS-01 剂量的提高和处理时间的延长,MDA-MB-468 和MDA-MB-231 细胞中磷酸化STAT3 蛋白、Bcl-xL 和Cylin D1 表达均降低,细胞内自噬标志蛋白LC3B表达上升;同时出现高密度、多层的团状自噬小体;细胞周期阻滞于S 期,并且凋亡率显著升高（P<0.05 或P<0.01）。结论：LFS-01 可阻断CRM1 运载蛋白出核、进而抑制STAT3 信号通路的激活,从而促进TNBC 细胞MDA-MB-468 和MDA-MB-231 发生自噬、细胞周期阻滞和凋亡。