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mTOR-dependent pathways in skin carcinogenesis

皮肤癌发生中的 mTOR 依赖性途径

基本信息

批准号：
8145690
负责人：
LISA M SHANTZ
金额：
$ 18.96万
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：
2010
资助国家：
美国
起止时间：
2010-09-21 至 2013-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8145690
关键词：
Ablation Address Alleles Apoptosis Apoptotic Back Biogenesis Biological Assay Bromodeoxyuridine CD34 gene Calcineurin inhibitor Calcium Cell Proliferation Cell Size Cells Clinical Trials Defect Development Differentiation Antigens Differentiation and Growth Epidermis Epithelial Estrogen Receptors Eukaryota Event Gene Expression Profile Generations Growth Growth Factor Hair follicle structure Homeostasis Human Immune In Vitro Integrins Ker10 protein Keratin Kidney Transplantation Label Maintenance Malignant Conversion Malignant Neoplasms Malignant neoplasm of prostate Measures Modeling Mus Mutation Newborn Infant Normal Cell Nude Mice Nutrient Oncogenic Papilloma Pathway interactions Patients Phenotype Prevention therapy Protein Biosynthesis Proteins Public Health Raptors Ribosomes Role Series Sirolimus Skin Skin Cancer Skin Carcinogenesis Skin Carcinoma Skin Neoplasms Small Interfering RNA Stem cells Tamoxifen Topical application Transplant Recipients Tumor Promoters Tumor Promotion Ultraviolet B Radiation Work Xenograft procedure analog base carcinogenesis cell growth cell transformation chemotherapy comparative dimethylbenzanthracene inhibitor/antagonist insight irradiation keratinocyte keratinocyte differentiation knock-down mTOR protein mouse model neoplastic cell novel prevent protein complex public health relevance recombinase research study response stem tumor tumor initiation ultraviolet irradiation v-Ha-ras Oncogene

项目摘要

DESCRIPTION (provided by applicant): The mammalian target of rapamycin (mTOR) is a central regulator of cell growth that is activated by a large number of cancer-promoting mutations. mTOR exists in two multi-protein complexes: mTORC1, which activates protein synthesis, and mTORC2, which is upstream of Akt-dependent anti-apoptotic pathways. The mTORC1 inhibitor Rapamycin and its analogues are in clinical trials against a variety of malignancies. While mTOR inhibition offers much promise as a chemotherapeutic strategy, the differential roles of mTORC1- and mTORC2-dependent pathways in carcinogenesis have only begun to be explored. A role for mTOR-controlled pathways in non-melanoma skin cancer (NMSC) has been suggested in recent clinical trials showing that renal transplant patients administered Rapamycin as an immune suppressant suffer from significantly fewer NMSCs compared to patients taking Calcineurin inhibitors. The central hypothesis of the proposed work is that both mTORC1 and mTORC2 activities within keratinocyte stem cells are essential for the initiation and promotion of NMSC. We show that topical application of Rapamycin to mouse skin inhibits epidermal hyperproliferation in response to the tumor promoter TPA and sensitizes keratinocytes to apoptosis following UV irradiation. It is known that mTORC2 can also respond to Rapamycin treatment, either by activation or inhibition, and mTORC2 is required for the development of prostate cancers dependent on Akt hyperactivation. Aberrant Akt activation has also been demonstrated in mouse models of NMSC. The proposed experiments will use a CreLoxP approach to differentiate between mTORC1- and mTORC2-specific effects in NMSC by creating mouse lines with conditional deletion of Raptor to abrogate mTORC1 or Rictor to abrogate mTORC2 in the skin. A number of studies have indicated that stem cells within the hair follicle bulge give rise to NMSC. Thus, mice with a floxed raptor or rictor allele will be crossed with K5CreERT2 mice, allowing Raptor or Rictor deletion to occur in the follicular bulge upon topical Tamoxifen application. We will use these mice to address the hypothesis that both mTORC1 and mTORC2 activities are required to maintain keratinocyte stem cell homeostasis and to become oncogenically transformed. Aim 1 will examine the effect of Raptor or Rictor deletion on the development of skin tumors using the classical DMBA/TPA initiation-promotion model, and will analyze the stem cell apoptotic response to DMBA. In Aim 2, changes in the stem and progenitor cell compartments that occur with loss of Raptor or Rictor will be evaluated. To measure the response to a primary oncogenic event, isolated Raptor ? ?Cre or Rictor / -Cre keratinocytes will be transduced with v-Ha-ras. Differentiation changes and the ability to form papillomas on nude mice will be assessed. Aim 3 will perform transcriptional profiling of stem cell-enriched Raptor / -Cre and Rictor / -Cre keratinocytes, allowing insight into other potential targets in NMSC. If our hypothesis is confirmed, these studies will provide a strong rationale for development of mTORC1- and mTORC2-specific inhibitors in skin and other epithelial tumors. PUBLIC HEALTH RELEVANCE: Our research studies the role of mTOR-dependent pathways in development of non-melanoma skin cancer. Since skin cancers are the most common form of malignancies world-wide, identification of possible targets for prevention and therapy is highly relevant to public health. Understanding the role of the mTORC1 and mTORC2 protein complexes is also of great importance because the mTOR inhibitor Rapamycin has shown great promise in chemotherapy of a variety of human cancers.

描述（由申请人提供）：哺乳动物雷帕霉素靶标（mTOR）是细胞生长的中央调节因子，可被大量促癌突变激活。 mTOR 存在于两种多蛋白复合物中：mTORC1（激活蛋白质合成）和 mTORC2（Akt 依赖性抗凋亡途径的上游）。 mTORC1 抑制剂雷帕霉素及其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 mTORC1 和 mTORC2 依赖性途径在癌发生中的不同作用才刚刚开始被探索。最近的临床试验表明，mTOR 控制的通路在非黑色素瘤皮肤癌 (NMSC) 中发挥作用，表明使用雷帕霉素作为免疫抑制剂的肾移植患者与服用钙调神经磷酸酶抑制剂的患者相比，其 NMSC 数量明显减少。这项工作的中心假设是角质形成细胞干细胞内的 mTORC1 和 mTORC2 活性对于 NMSC 的启动和促进至关重要。我们发现，在小鼠皮肤上局部施用雷帕霉素可抑制表皮对肿瘤促进剂 TPA 的过度增殖，并使角质形成细胞对紫外线照射后的细胞凋亡敏感。众所周知，mTORC2 也可以通过激活或抑制对雷帕霉素治疗做出反应，并且 mTORC2 是依赖于 Akt 过度激活的前列腺癌发展所必需的。异常的 Akt 激活也在 NMSC 小鼠模型中得到证实。拟议的实验将使用 CreLoxP 方法来区分 NMSC 中 mTORC1 和 mTORC2 特异性效应，方法是创建具有条件删除 Raptor 的小鼠品系，以消除皮肤中的 mTORC1 或 Rictor 来消除 mTORC2。许多研究表明，毛囊凸起内的干细胞会产生 NMSC。因此，具有 floxed raptor 或 rictor 等位基因的小鼠将与 K5CreERT2 小鼠杂交，从而在局部应用他莫昔芬时，在毛囊隆起处发生 Raptor 或 Rictor 缺失。我们将使用这些小鼠来解决以下假设：mTORC1 和 mTORC2 活性都是维持角质形成细胞干细胞稳态和致癌转化所必需的。目标 1 将使用经典的 DMBA/TPA 启动-促进模型检查 Raptor 或 Rictor 缺失对皮肤肿瘤发展的影响，并将分析干细胞对 DMBA 的凋亡反应。在目标 2 中，将评估因 Raptor 或 Rictor 损失而发生的干细胞和祖细胞区室的变化。为了测量对主要致癌事件的反应，分离了猛禽？ ?Cre 或 Rictor / -Cre 角质形成细胞将用 v-Ha-ras 转导。将评估分化变化和在裸鼠上形成乳头状瘤的能力。 Aim 3 将对富含干细胞的 Raptor / -Cre 和 Rictor / -Cre 角质形成细胞进行转录分析，从而深入了解 NMSC 中的其他潜在靶标。如果我们的假设得到证实，这些研究将为皮肤和其他上皮肿瘤中 mTORC1 和 mTORC2 特异性抑制剂的开发提供强有力的理论依据。公共健康相关性：我们的研究研究 mTOR 依赖性途径在非黑色素瘤皮肤癌发展中的作用。由于皮肤癌是世界范围内最常见的恶性肿瘤，因此确定可能的预防和治疗目标与公共卫生高度相关。了解 mTORC1 和 mTORC2 蛋白复合物的作用也非常重要，因为 mTOR 抑制剂雷帕霉素在多种人类癌症的化疗中显示出巨大的前景。