Interacting Signaling Pathways that Initiate Squamous Cell Carcinogenesis

引发鳞状细胞癌变的相互作用信号通路

基本信息

批准号：
9343520
负责人：
STUART H. YUSPA
金额：
$ 119.42万
依托单位：
DIVISION OF BASIC SCIENCES - NCI
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/9343520
关键词：
Alleles Benign Biochemistry Biological Biological Response Modifiers Biology Bladder CXCL1 gene CXCL2 gene Carcinoma Cell Culture Techniques Cells Characteristics Clonal Evolution Colon Control Groups Cultured Cells Development Disintegrins Elements Epidermal Growth Factor Receptor Epidermis Epigenetic Process Epithelial Cells Epithelium Esophagus Event Feedback Gene Expression Profile Genes Genetic Growth HRAS gene Human Indium Inflammation Inflammatory Interleukin-1 alpha Interruption KRAS2 gene Lesion Ligands Malignant Conversion Malignant Neoplasms Malignant Squamous Cell Neoplasm Mediating Membrane Methods Modeling Molecular Molecular Profiling Mus Mutation Oncogenic Oral cavity Papilloma Pathogenesis Pathway interactions Patients Pharmaceutical Preparations Phenotype Phospholipase C Premalignant Protocols documentation RNA Signal Pathway Skin Skin Carcinogenesis Skin Neoplasms Specificity Squamous Cell Squamous Cell Papillomas Squamous cell carcinoma Staging Stimulus TP53 gene Testing Tissue Array Analysis Tissues Transcend Transforming Growth Factor beta Transgenic Mice Tyrosine Up-Regulation angiogenesis autocrine carcinogenesis chemokine dimethylbenzanthracene in vivo keratinocyte knock-down migration mutant neoplastic overexpression paracrine prevent programs promoter receptor rho senescence src-Family Kinases therapeutic target tumor tumor initiation

项目摘要

In the skin model activating mutations in H-ras, K-ras and N-ras are sufficient to produce the clonal benign squamous papilloma expressing the phenotype of the initiated cell. Utilizing H-ras transduced isolated primary keratinocytes, we have demonstrated that oncogenic Ras upregulates EGFR ligands, establishing a positive feedback loop through EGFR, thus increasing proliferation and simultaneously activating src kinases to tyrosine phosphorylate and inactivate PKC delta, thereby inhibiting PKC-dependent keratinocyte terminal differentiation. Contemporaneous H-ras mediated activation of phospholipase C and PKCalpha establishes a second feedback loop through IL-1alpha and its receptor, activating MyD88 and NFkB to establish a unique gene expression profile characteristic of both initiated cells and papillomas. Interruption of any of these interacting pathways by drugs, knockdown or genetic deletion reduces or prevents tumor formation. An important downstream effector of these interacting pathways is the upregulation and release of chemokines such as CXCL1 and CXCL2 that act in a paracrine mode to attract inflammatory cells and stimulate angiogenesis and an autocrine mode to promote migration of initiated cells. Interruption of any of these pathways inhibits tumor formation. We have also discovered a fundamental function for Adam17, a disintegrin required for the release of EGFR ligands from their membrane attachment. Knockdown of Adam17 prevents the activation of EGFR in H-ras transformed keratinocytes. Preliminary studies indicate that H-ras mediates Adam17 activity via as yet undetermined action on iRhom1 and iRhom2 that are required for Adam17 membrane localization and maturation. Tissue array analysis of human skin tumors indicates that MET is abundantly expressed in progressing squamous carcinomas along with its ligand HGF. We induced tumors with DMBA and TPA on transgenic mice that overexpress HGF and noted a marked increase in papillomas and carcinomas relative to control groups. Further analysis revealed that activation of MET in epidermis is sufficient to initiate tumor formation after TPA promotion in the absence of DMBA. In isolated keratinoctyes, activation of MET mimics the H-ras initiated phenotype reproducing the EGFR and other required feedback loops. However, the application of DMBA to mice with activated MET produces more carcinomas with K-ras mutations than application of DMBA to control mice where H-ras mutations dominate, suggesting that tissue context influences the selection of ras mutations in tumors. RNA profiling of initiated mouse keratinocytes produced by MET or H-ras activation has revealed signature gene expression changes common to both and not previously associated with tumor initiation. Current studies are extending the analysis to K-ras initiated keratinocytes and using knockdown or overexpression approaches to test for critical elements in the common expression profiles essential for initiation and tumor formation. The pathways that have been defined for transforming mouse keratinocytes are also being tested in human keratinocytes transformed by the oncogenic H-, K- and N- ras alleles. Keratinocytes and other epithelial cells may respond to oncogenic stimuli such as mutant ras alleles by activating a senescence program. Current studies indicate that this program in keratinocytes is mediated by the Rho pathway and depends on the activation of p19/Arf and p21. Antagonism of this pathway provides an opportunity to evaluate the cellular biochemistry associated with premalignant progression and malignant conversion.

在皮肤模型中，激活 H-ras、K-ras 和 N-ras 突变足以产生表达起始细胞表型的克隆良性鳞状乳头状瘤。利用 H-ras 转导的分离原代角质形成细胞，我们证明致癌 Ras 上调 EGFR 配体，通过 EGFR 建立正反馈环，从而增加增殖并同时激活 src 激酶，使酪氨酸磷酸化并使 PKC δ 失活，从而抑制 PKC 依赖性角质形成细胞末端差异化。 H-ras 介导的磷脂酶 C 和 PKCα 的同时激活通过 IL-1α 及其受体建立了第二个反馈回路，激活 MyD88 和 NFkB，从而建立起始细胞和乳头状瘤的独特基因表达谱特征。通过药物、基因敲低或基因缺失来中断任何这些相互作用的途径，可以减少或预防肿瘤的形成。这些相互作用途径的一个重要下游效应器是趋化因子（例如 CXCL1 和 CXCL2）的上调和释放，它们以旁分泌模式作用以吸引炎症细胞并刺激血管生成，以自分泌模式作用以促进起始细胞的迁移。任何这些途径的中断都会抑制肿瘤的形成。我们还发现了 Adam17 的一个基本功能，即 EGFR 配体从膜附着物上释放所需的解整合素。 Adam17 的敲低可阻止 H-ras 转化的角质形成细胞中 EGFR 的激活。初步研究表明，H-ras 通过对 Adam17 膜定位和成熟所需的 iRhom1 和 iRhom2 的尚未确定的作用来介导 Adam17 活性。人类皮肤肿瘤的组织阵列分析表明，MET 及其配体 HGF 在进展性鳞状癌中大量表达。我们用 DMBA 和 TPA 在过度表达 HGF 的转基因小鼠上诱导肿瘤，并注意到相对于对照组，乳头状瘤和癌明显增加。进一步分析表明，在缺乏 DMBA 的情况下，在 TPA 促进后，表皮中 MET 的激活足以引发肿瘤形成。在分离的角质细胞中，MET 的激活模仿 H-ras 启动的表型，复制 EGFR 和其他所需的反馈环路。然而，与应用 DMBA 控制 H-ras 突变占主导地位的小鼠相比，将 DMBA 应用于具有激活 MET 的小鼠会产生更多带有 K-ras 突变的癌症，这表明组织环境影响肿瘤中 ras 突变的选择。对 MET 或 H-ras 激活产生的起始小鼠角质形成细胞进行 RNA 分析，揭示了两者共有的特征基因表达变化，并且之前与肿瘤发生无关。目前的研究正在将分析扩展到 K-ras 启动的角质形成细胞，并使用敲低或过表达方法来测试启动和肿瘤形成所必需的常见表达谱中的关键元素。已确定的用于转化小鼠角质形成细胞的途径也在由致癌 H-、K- 和 N-ras 等位基因转化的人类角质形成细胞中进行测试。角质形成细胞和其他上皮细胞可能通过激活衰老程序来响应致癌刺激，例如突变的 ras 等位基因。目前的研究表明，角质形成细胞中的这一程序是由 Rho 途径介导的，并且依赖于 p19/Arf 和 p21 的激活。该途径的拮抗作用提供了评估与癌前进展和恶性转化相关的细胞生物化学的机会。