小细胞肺癌干细胞信号通路的研究进展

小细胞肺癌是具有高度侵袭性的肺肿瘤,其主要临床特征是化疗有效率高但易在短时间内复发转移,这一特点可能与肿瘤干细胞的存在有关。肿瘤干细胞被认为是恶性肿瘤发生发展、耐药、复发及转移的根源。目前多认为肿瘤干细胞与正常干细胞有着相同的信号通路,如Hedgehog、Notch、Wnt等通路。本文就这几条信号通路在小细胞肺癌干细胞中所起的作用以及针对这几条信号通路治疗药物的研究进展和可能的信号通路交互作用等方面进行综述。     

过度活化Notch1信号促进肾癌细胞增殖的机制研究

目的 研究Notch1信号过度活化对肾癌细胞增殖的影响及其可能的分子机制。方法 首先应用免疫组织化学法检测120例肾透明细胞癌患者的肿瘤组织中Notch1的表达水平,并结合患者的临床病理特征进行比较。然后在肾癌细胞系ACHN中开展体外的机制和功能研究。用Western blot检测Notch1过度活化对PI3K/Akt信号通路的调控。并进一步分析Notch1和PI3K/Akt信号通路对细胞增殖和细胞周期的影响。结果 120例肾透明细胞癌组织标本中,有64例高表达Notch1,占53.3%。Notch1在直径≥7cm的肿瘤中的表达强度要高于直径＜7cm的肿瘤(P = 0.005)。与局限期(TNM Ⅰ～Ⅱ)肾癌相比,进展期(TNM Ⅲ～Ⅳ期)肾癌有高表达Notch1的趋势(P = 0.062)。结论 肾癌细胞中过度活化的Notch1信号,通过上调PI3K/Akt信号通路的活性,加快了肿瘤细胞的增殖,进而促进肾癌的发生、发展。该发现提供了一种可能的肾透明细胞癌发生的新机制和潜在分子药靶。     

Notch1和表皮生长因子受体在舌鳞癌及癌前病变中的表达

目的研究舌鳞癌（TSCC）及癌前病变中Notch1的表达,探讨其与表皮生长因子受体（EGFR）之间的潜在关系。方法免疫组化检测41例人TSCC、39例舌黏膜白斑（LP）和7例正常舌黏膜标本中Notch1和EGFR的表达。结果在正常舌黏膜和LP中,Notch1阳性表达主要位于角化层,部分颗粒层和棘层细胞也有表达,基底层无表达;而EGFR阳性表达主要位于基底层,棘层少见表达,颗粒层和角化层无表达。在TSCC中,Notch1阳性表达多见于癌巢中鳞状化生的角化细胞及类棘层细胞,周边细胞无表达;而EGFR阳性表达主要位于癌巢周边细胞,鳞状化生的角化细胞及类棘层细胞无表达。结论Notch1在舌黏膜上皮中促进细胞分化,在TSCC中起抑癌作用;而EGFR的表达可能抑制Notch1的表达,以维持细胞增殖,并促进TSCC发生发展。     

High tumor levels of IL6 and IL8 abrogate preclinical efficacy of the γ-secretase inhibitor, RO4929097

Interest continues to build around the early application of patient selection markers to prospectively identify patients likely to show clinical benefit from cancer therapies. Hypothesis generation and clinical strategies often begin at the preclinical stage where responder and nonresponder tumor cell lines are first identified and characterized. In the present study, we investigate the drivers of in vivo resistance to the γ-secretase inhibitor RO4929097. Beginning at the tissue culture level, we identified apparent IL6 and IL8 expression differences that characterized tumor cell line response to RO4929097. We validated this molecular signature at the preclinical efficacy level identifying additional xenograft models resistant to the in vivo effects of RO4929097. Our data suggest that for IL6 and IL8 overexpressing tumors, RO4929097 no longer impacts angiogenesis or the infiltration of tumor associated fibroblasts. These preclinical data provide a rationale for preselecting patients possessing low levels of IL6 and IL8 prior to RO4929097 dosing. Extending this hypothesis into the clinic, we monitored patient IL6 and IL8 serum levels prior to dosing with RO4929097 during Phase I. Interestingly, the small group of patients deriving some type of clinical benefit from RO4929097 presented with low baseline levels of IL6 and IL8. Our data support the continued investigation of this patient selection marker for RO4929097 and other types of Notch inhibitors undergoing early clinical evaluation.     

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目的    探讨姜黄素对人口腔鳞癌细胞的增殖抑制作用及作用机制。方法    2009年3—12月于青岛大学医学院选用人舌鳞癌细胞系Tca8113及其脑转移亚系Tb为研究对象,分别用6.25、12.5、25、50 μmol／L姜黄素处理,阴性对照仅加入RPMI1640培养液,用MTT法测定细胞增殖抑制率;以免疫细胞化学方法检测25 μmol／L姜黄素处理后细胞内β-连环蛋白和Notch1的表达。结果    姜黄素对口腔鳞癌细胞Tca8113及Tb增殖有明显抑制作用,并呈剂量依赖性。免疫细胞化学检测结果表明,25 μmol／L姜黄素作用口腔鳞癌细胞系Tca8113及Tb 24 h后即可明显下调β-连环蛋白的表达水平（P < 0.05）,上调Notch1表达水平（P < 0.05）。结论    姜黄素对人口腔鳞癌细胞系Tca8113及Tb的增殖具有抑制作用,其作用机制可能与细胞内β-连环蛋白表达水平下调和Notch1表达水平上调有关。     

Antiangiogenic agents and targets: A perspective

The first generation of clinically useful antiangiogenic agents focused on VEGF and targets in the VEGF pathway. The strengths and limitations of these therapeutics are now clear. Some tumors do not respond to VEGF-directed therapies de novo and others become non-responsive or resistant over time by switching to other angiogenic pathways. The next generation of angiogenesis-directed therapeutics will expand the field beyond the VEGF pathway and become more disease selective. Placental growth factor, a protein closely related to VEGF, is induced as tumors lose responsiveness to VEGF-directed therapies. Angiopoietins 1 and 2 are being targeted with a unique peptibody, a human recombinant Fc constant region fused to peptides, in clinical trials. The HGF/c-Met pathway is upregulated in some tumors as an alternate angiogenic pathway. The CXCL12 (SDF-1)/CXCR4 pathway represents a stromal chemokine axis involved in tumor angiogenesis. CXCR2 is a G-protein coupled receptor with several ligands including interleukin-8 and other angiogenic cytokines and may represent a useful target for antiangiogenic agents. The notch pathway is being investigated as a target in the setting of tumor angiogenesis. Sphingosine-1-phosphate is a bioactive lipid that can be neutralized with a monoclonal antibody. The anti-S-1-P antibody is under investigation as an antiangiogenic agent. Finally, several multi-targeted kinase inhibitors each with a unique pattern of inhibitory potency are in clinical trial with a focus on antiangiogenic activity. The expansion of the scope of potential antiangiogenic agents in or entering clinical trial should allow the development of antiangiogenic combination regimens and single agents that address diseases refractory to VEGF-directed therapeutics.     

Osteogenic oxysterol, 20(S)‐hydroxycholesterol,induces notch target gene expression in bone marrow stromal cells

We previously reported that specific oxysterols stimulate osteogenic differentiation of pluripotent bone marrow stromal cells (MSCs) through activation of hedgehog (Hh) signaling and may serve as potential future therapies for intervention in osteopenia and osteoporosis. In this study we report that the osteogenic oxysterol 20(S)‐hydroxycholesterol (20S) induces the expression of genes associated with Notch signaling. Using M2‐10B4 (M2) MSCs, we found that 20S significantly induced HES‐1, HEY‐1, and HEY‐2 mRNA expression compared with untreated cells, with maximal induction after 48 hours, whereas the nonosteogenic oxysterols did not. Similar observations were made when M2 cells were treated with sonic hedgehog (Shh), and the specific Hh pathway inhibitor cyclopamine blocked 20S‐induced Notch target gene expression. 20S did not induce Notch target genes in Smo^?/? mouse embryonic fibroblasts, further confirming the role of Hh signaling in 20S‐induced expression of Notch target genes. Despite the inability of liver X‐receptor (LXR) synthetic ligand TO901317 to induce Notch target genes in M2 cells, LXR knockdown studies using siRNA showed inhibition of 20S‐induced HEY‐1 but not HES‐1 expression, suggesting the partial role of LXR signaling in MSC responses to 20S. Moreover, 20S‐induced Notch target gene expression was independent of canonical Notch signaling because neither 20S nor Shh induced CBF1 luciferase reporter activity or NICD protein accumulation in the nucleus, which are hallmarks of canonical Notch signaling activation. Finally, HES‐1 and HEY‐1 siRNA transfection significantly inhibited 20S‐induced osteogenic genes, suggesting that the pro‐osteogenic effects of 20S are regulated in part by HES‐1 and HEY‐1. © 2010 American Society for Bone and Mineral Research     

烧伤创面内Notch信号因子变化临床研究

目的探讨Notch信号在创面愈合中的作用,为临床治疗提供依据。方法选取2015年5月至2016年5月西京医院烧伤外科收治的中重度烧伤患者25例为研究对象。分别切取烧伤创面不同部位标本行ABC免疫复合物法免疫组织化学染色,观察判断组织中Notch1、Jagged1、NICD蛋白的含量和分布情况。结果受体Notch1、配体Jagged1、活化信号NICD在烧伤创面内有明显的一致表达。在创面上皮愈合边缘部位,三者均表达最强;在创面中心肉芽部位,三者表达较弱;正常皮肤组织三者无明显的表达。结论烧伤创面内不同部位受体Notch1、配体Jagged1、活化信号NICD的表达强度和分布情况不同,其变化与创面愈合密切相关,在促进创面愈合方面有很重要的作用。     

Notch信号通路在肝癌细胞迁移过程中的作用及机制

目的:探讨Notch信号通路在肝癌细胞迁移过程中的作用及相关机制。方法:体外培养肝癌细胞系SMMC-7721、MHCC97H和正常非肿瘤肝细胞系HL-7702,利用Transwell小室检测细胞的迁移能力,Western blot检测Notch1、Snail、E-cadherin、COX-2(环氧化酶-2)蛋白的表达。分别采用5μmol/L DAPT（3,5-二氟苯乙酰-L-丙氨酰-S苯基甘氨酸t-丁酯,γ-分泌酶抑制剂）阻断Notch信号通路和50μmol/L NS-398阻断COX-2,比较对细胞迁移能力的影响以及对肝癌细胞中Snail、E-cadherin表达的影响。结果:Notch1、Snail、E-cadherin、COX-2参与了肝癌细胞迁移过程,DAPT通过阻断Notch显著上调E-cadherin,影响细胞的迁移（P<0.05）,下调Snail和COX-2,NS-398通过阻断COX-2影响细胞的迁移（P<0.05）。结论:Notch信号通路在肝癌细胞迁移过程中起着非常重要的作用,其机制初步认为与Snail、E-cadherin、COX-2的表达有关。