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：
7596470
负责人：
LISA M SHANTZ
金额：
$ 7.74万
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/7596470
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 Cyclin D1 Cytoskeletal Modeling Development Dimethyl Sulfoxide Early treatment Epidermis Epigenetic Process Estrogen Receptors Evaluation Exons Formalin Future Generations Genes Genetic Hair follicle structure Human Immune Incidence Individual Keratin Kidney Transplantation Knock-out Lead Link Macrolide Antibiotics Malignant Neoplasms Medicine Messenger RNA Mitogens Mus Mutate Mutation 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 Role Sampling Sirolimus Site Skin Skin Cancer Skin Carcinogenesis Skin Carcinoma Skin Neoplasms Staging Stem cells Structure System Tamoxifen Testing Time Transgenic Organisms Translations Transplant Recipients Tumor Promoters Tumor Promotion Untranslated Regions Work analog c-myc Genes cancer chemoprevention carcinogenesis cell growth college design epidermis cell high risk inhibitor/antagonist keratinocyte mTOR protein mouse model promoter protective effect protein expression recombinase research study response tumor tumor initiation tumorigenesis

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）：癌发生是由肿瘤的发生、促进和进展驱动的。肿瘤的进展会发生多种表观遗传变化，这些变化是高危个体化学预防药物早期干预的潜在目标。哺乳动物雷帕霉素靶标 (mTOR) 位于 Rasand PI 3 激酶控制途径的下游，可被大量促癌突变激活。 mTOR 复合物 mTORC1 和 mTORC2 控制多种细胞过程，包括核糖体生物发生、细胞骨架组织和蛋白质合成，使 mTOR 成为细胞生长的中心调节因子。天然存在的大环内酯类抗生素雷帕霉素及其类似物是 mTORC1 的高度特异性抑制剂，并且几种雷帕霉素类似物正在进行针对多种恶性肿瘤的临床试验。虽然 mTOR 抑制作为一种化疗策略具有很大的前景，但 mTOR 在化学预防中的作用在很大程度上仍未得到探索。最近的临床试验表明，与服用钙调神经磷酸酶抑制剂的患者相比，服用雷帕霉素作为免疫抑制剂的肾移植患者患非黑色素瘤皮肤癌的几率显着降低，这表明 mTOR 是化学预防皮肤癌的有效靶点。我们提供的初步证据表明，mTOR 小鼠皮肤中 mTOR 的减少会降低 4EBP1 磷酸化，并减弱鸟氨酸脱羧酶 (ODC) 对肿瘤启动子 TPA 的反应。与许多增殖相关基因一样，ODC mRNA 包含一个长的 5'-非翻译区，以帽子依赖性方式进行调节。因此，mTOR 抑制带来的翻译变化可以显着影响总蛋白。拟议的实验将使用 CreLoxP 方法通过条件删除来敲除皮肤中的 mTOR。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 K14CreERT 小鼠杂交，该小鼠表达与雌激素受体融合的他莫昔芬诱导性 Cre 重组酶，生成 K14CreERT/mTORlox/lox 小鼠。将他莫昔芬涂抹在皮肤上会触发由角蛋白14启动子驱动的Cre表达，从而消除毛囊外根鞘和毛囊间表皮基底细胞层中的mTOR。 mTOR 的缺失将抑制 mTORC1 和 mTORC2 依赖性途径，这与雷帕霉素不同，雷帕霉素被认为在大多数系统中抑制 mTORC1 但激活 mTORC2。我们将在两个特定目标中使用 DMBA/TPA 诱导皮肤肿瘤发生的两阶段小鼠模型，旨在确定 mTOR 对于增殖相关基因在肿瘤促进中的早期反应至关重要，并且 mTOR 消融可降低皮肤肿瘤的发生率和多重性。目标 1 将生成并表征 K14CreERT/mTORlox/lox 小鼠，而目标 2 将测试条件 mTOR 消融对 DMBA/TPA 治疗小鼠的蛋白质表达和皮肤肿瘤发展的影响。这些研究将验证 mTOR 作为化学预防的靶点，并导致未来的工作确定 mTOR 控制的肿瘤促进所需的遗传和表观遗传变化。