Evaluation of mTOR as a chemoprevention target in skin cancer

mTOR 作为皮肤癌化学预防靶点的评估

基本信息

批准号：
7475350
负责人：
LISA M SHANTZ
金额：
$ 7.68万
依托单位：
PENNSYLVANIA STATE UNIV HERSHEY MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-01 至 2010-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7475350
关键词：
1-Phosphatidylinositol 3-Kinase 5&apos Untranslated Regions Ablation Affect Alleles Apoptosis Basal Cell Biogenesis Biological CCI-779 Calcineurin inhibitor Catalytic Domain Cell physiology Cells Chemoprevention Chemopreventive Agent Chimeric Proteins Clinical Trials Complex Condition Cyclin D1 Cytoskeletal Modeling Development Dimethyl Sulfoxide Early Intervention Epidermis Epigenetic Process Estrogen Receptors Evaluation Exons Formalin Future Generations Genes Genetic Hair follicle structure Human Immune Incidence Individual Kidney Transplantation Knock-out Lead Link Macrolide Antibiotics Malignant Neoplasms Medicine Messenger RNA Mitogens Mus Mutate Mutation Numbers Nutrient Ornithine Decarboxylase Outcome Paraffin Embedding Pathway interactions Patients Phosphorylation Phosphotransferases Pilot Projects Plant Roots Process Protein Biosynthesis Protein Kinase Proteins Protocols documentation RNA Ribosomes Risk Role Sampling Sirolimus Site Skin Skin Cancer Skin Carcinogenesis Skin Carcinoma Skin Neoplasms Staging Stem cells Structure System Tamoxifen Testing Thinking Time Transgenic Organisms Translations Transplant Recipients Tumor Promoters Tumor Promotion Untranslated Regions Week Work analog c-myc Genes carcinogenesis cell growth college design epidermis cell human FRAP1 protein inhibitor/antagonist keratin 14, K14 keratinocyte mouse model promoter protective effect protein expression recombinase research study response size tumor tumor initiation tumorigenesis

1-Phosphatidylinositol 3-Kinase 5&apos Untranslated Regions Ablation Affect Alleles Apoptosis Basal Cell Biogenesis Biological CCI-779 Calcineurin inhibitor Catalytic Domain Cell physiology Cells Chemoprevention Chemopreventive Agent Chimeric Proteins Clinical Trials Complex Condition Cyclin D1 Cytoskeletal Modeling Development Dimethyl Sulfoxide Early Intervention Epidermis Epigenetic Process Estrogen Receptors Evaluation Exons Formalin Future Generations Genes Genetic Hair follicle structure Human Immune Incidence Individual Kidney Transplantation Knock-out Lead Link Macrolide Antibiotics Malignant Neoplasms Medicine Messenger RNA Mitogens Mus Mutate Mutation Numbers Nutrient Ornithine Decarboxylase Outcome Paraffin Embedding Pathway interactions Patients Phosphorylation Phosphotransferases Pilot Projects Plant Roots Process Protein Biosynthesis Protein Kinase Proteins Protocols documentation RNA Ribosomes Risk Role Sampling Sirolimus Site Skin Skin Cancer Skin Carcinogenesis Skin Carcinoma Skin Neoplasms Staging Stem cells Structure System Tamoxifen Testing Thinking Time Transgenic Organisms Translations Transplant Recipients Tumor Promoters Tumor Promotion Untranslated Regions Week Work analog c-myc Genes carcinogenesis cell growth college design epidermis cell human FRAP1 protein inhibitor/antagonist keratin 14, K14 keratinocyte mouse model promoter protective effect protein expression recombinase research study response size tumor tumor initiation tumorigenesis

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项目摘要

DESCRIPTION (provided by applicant): Carcinogenesis is driven by tumor initiation, promotion and progression. There are a variety of epigenetic changes that occur with tumor promotion that are potential targets for early intervention by chemopreventive agents in high-risk individuals. The mammalian target of rapamycin (mTOR), which is downstream of both Rasand PI 3-kinase-controlled pathways, is activated by a large number of cancer-promoting mutations. The mTOR complexes mTORC1 and mTORC2 control diverse cellular processes, including ribosome biogenesis, cytoskeletal organization and protein synthesis, making mTOR a central regulator of cell growth. The naturally occurring macrolide antibiotic rapamycin and its analogues are highly specific inhibitors of mTORC1, and several rapamycin analogues are undergoing clinical trials against a variety of malignancies. While mTOR inhibition offers much promise as a chemotherapeutic strategy, the role of mTOR in chemoprevention has remained largely unexplored. Recent clinical trials establishing that renal transplant patients administered rapamycin as an immune suppressant suffer from significantly fewer non-melanoma skin cancers compared to patients taking calcineurin inhibitors have suggested mTOR as a valid target for chemoprevention of skin carcinogenesis. We present preliminary evidence that the reduction of mTOR in the skin of mTOR mice decreases 4EBP1 phosphorylation and blunts the induction of ornithine decarboxylase (ODC) in response to the tumor promoter TPA. Like many proliferation-associated genes, the ODC mRNA contains a long 5'- untranslated region that is regulated in a cap-dependent manner. Thus, changes in translation brought about by mTOR inhibition can dramatically affect total protein. The proposed experiments will knock out mTOR in the skin by conditional deletion using a CreLoxP approach. Mice containing a floxed mTOR allele, provided by our collaborator Dr. C.J. Lynch, will be crossed with commercially available K14CreERT mice, which express a tamoxifen-inducible Cre recombinase fused to the estrogen receptor, to generate K14CreERT/mTORlox/lox mice. Application of tamoxifen to the skin triggers expression of Cre driven by the keratin 14 promoter, which will ablate mTOR in the outer root sheath of the hair follicle and the basal cell layer of the interfollicular epidermis. Deletion of mTOR will inhibit both mTORC1- and mTORC2-dependent pathways, unlike rapamycin, which is thought to inhibit mTORC1 but activate mTORC2 in most systems. We will use the two-stage mouse model of DMBA/TPA-induced skin tumorigenesis in two Specific Aims designed to establish that mTOR is critical for the early response of proliferation-associated genes in tumor promotion, and mTOR ablation reduces skin tumor incidence and multiplicity. Aim 1 will generate and characterize K14CreERT/mTORlox/lox mice, while Aim 2 will test the effect of conditional mTOR ablation on protein expression and skin tumor development in DMBA/TPA-treated mice. These studies will validate mTOR as a target for chemoprevention, and lead to future work identifying the genetic and epigenetic changes necessary for tumor promotion that are controlled by mTOR.

描述（由申请人提供）：致癌作用是由肿瘤的启动，促进和进展驱动的。肿瘤促进发生了多种表观遗传变化，这些变化是化学预防药物早期干预的潜在靶标。雷帕霉素的哺乳动物靶标（MTOR）是两种RASAND PI 3-激酶控制途径的下游，被大量促进癌症的突变激活。 MTOR复合物MTORC1和MTORC2控制了各种细胞过程，包括核糖体生物发生，细胞骨架组织和蛋白质合成，使MTOR成为细胞生长的核心调节剂。天然存在的大花环抗生素雷帕霉素及其类似物是MTORC1的高度特异性抑制剂，几种雷帕霉素类似物正在针对多种恶性肿瘤进行临床试验。尽管MTOR抑制作用作为化学治疗策略提供了很大的希望，但MTOR在化学预防中的作用仍未得到探索。最近的临床试验表明，与服用钙调神经磷酸酶抑制剂相比，肾移植患者将雷帕霉素作为免疫抑制剂的非黑质膜皮肤癌的遭受了明显较少的非黑质膜皮肤癌，这表明MTOR是对皮肤癌发生化学预订的有效靶标。我们提供了初步证据，表明MTOR小鼠皮肤中MTOR的减少可降低4EBP1磷酸化，并钝化鸟氨酸脱羧酶（ODC），以响应肿瘤启动子TPA。像许多相关基因一样，ODC mRNA包含一个长5'-未翻译区域，以帽依赖性方式调节。因此，MTOR抑制作用带来的翻译变化会极大地影响总蛋白质。提出的实验将使用Creloxp方法通过条件缺失在皮肤中淘汰MTOR。由我们的合作者C.J. Lynch博士提供的含有Floxed MTOR等位基因的小鼠将与市售的K14Creert小鼠交叉，该小鼠表达了与雌激素受体融合的他莫昔芬可诱导的重组酶，以使K14Creert/mtorlolox/lox/lox mice融合在一起。他莫昔芬在皮肤上的应用触发了由角蛋白14启动子驱动的CRE的表达，该启动子将在毛囊的外根鞘中释放MTOR，以及胶体间表皮的基底细胞层。与雷帕霉素不同，MTOR的缺失将抑制MTORC1-和MTORC2依赖性途径，而雷帕霉素被认为可以抑制MTORC1，但在大多数系统中激活MTORC2。我们将使用两个特定目的使用DMBA/TPA诱导的皮肤肿瘤发生的两阶段小鼠模型，旨在确定MTOR对于肿瘤促进中增殖相关基因的早期反应至关重要，MTOR消融降低了皮肤肿瘤的发生率和多重性。 AIM 1将产生并表征K14Creert/mtorlox/Lox小鼠，而AIM 2将测试有条件的MTOR消融对DMBA/TPA处理的小鼠中蛋白质表达和皮肤肿瘤发育的影响。这些研究将验证MTOR作为化学预防的靶标，并导致未来的工作确定由MTOR控制的肿瘤促进所必需的遗传和表观遗传学变化。