Cell fate decisions in Merkel cell carcinoma initiation and maintenance

默克尔细胞癌发生和维持的细胞命运决定

• 批准号: 10549793
• 负责人: ANDRZEJ A. DLUGOSZ
• 金额: $ 51.44万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-20 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10549793
• 关键词: Adult; Aggressive behavior; Alleles; Antigen Targeting; Antigens; Behavior; Biological; Cancer Etiology; Cancer Model; Cell Line; Cell Lineage; Cells; Collection; Coupled; Development; Doxycycline; Genetically Engineered Mouse; Grant; Growth; Human; Immune; Large T Antigen; Maintenance; Malignant Epithelial Cell; Malignant Neoplasms; Merkel Cells; Merkel cell carcinoma; Messenger RNA; Modeling; Molecular; Mus; Neuroendocrine Cell; Neuroendocrine Tumors; Neurosecretory Systems; Pathogenesis; Phenotype; Play; Polyomavirus; Polyomavirus Transforming Antigens; Pre-Clinical Model; Production; Proliferating; Property; Resistance; Role; Skin; Skin Cancer; Small T Antigen; Suspensions; TP53 gene; Testing; Touch sensation; Transcript; Transplantation; Variant; Viral; Viral Oncogene; Virus; Work; candidate identification; cell type; cellular engineering; epidermal stem cell; experimental study; in vivo; inducible Cre; insight; keratinocyte; knock-down; loss of function; mouse model; neoplastic cell; neuroendocrine phenotype; novel strategies; postmitotic; progenitor; stem cells; transcription factor; transcriptome; transgene expression; tumor; tumor progression; tumorigenesis; tumorigenic

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine skin cancer that frequently carries an integrated copy of Merkel cell polyomavirus (MCPyV) and expresses viral transforming antigens (TAgs) that likely play a key role in tumorigenesis. MCC tumor cells also express transcripts detected in normal, post- mitotic Merkel cells residing in skin, including a set of mRNAs encoding lineage-specific transcription factors implicated in neuroendocrine cell fate. Work from our lab and others established that MCPyV small T antigen (sTAg), +/- truncated large T antigen (tLTAg), is sufficient to drive transformation in vivo, but MCC-like tumors were not detected in any of these models despite TAg targeting to various potential tumor progenitor. The lack of a viable mouse model of MCC has been a major impediment to progress in this field. Normal Merkel cells arise from epidermal progenitors in specialized cellular compartments called touch domes, but the cell of origin of MCC is unknown. In an effort to override the apparent resistance of multiple cell types to MCPyV TAg-driven MCC development in genetically-engineered mice, we generated mice co- expressing the Merkel cell transcription factor Atoh1, together with MCPyV TAgs, in epidermal keratinocytes. These mice developed small collections of proliferating MCC-like tumor cells, and when coupled with deletion of one copy of p53, yielded gross tumors strikingly similar to human MCCs based on multiple criteria. Given the pivotal role of Atoh1 in MCC tumorigenesis we performed complementary loss-of-function studies, and discovered that Atoh1 knock-down converts human MCC cells from their typical neuroendocrine phenotype and growth in suspension, to cells with adherent growth, loss of neuroendocrine markers, and more aggressive behavior in vivo. We thus hypothesize that Atoh1 and other transcription factors governing Merkel cell fate play a pivotal role in MCC pathogenesis as well as maintenance of the neuroendocrine tumor phenotype. We propose the following aims to test this hypothesis. 1) Generate and characterize MCC-like tumors driven by MCPyV TAg expression targeted to candidate MCC progenitor cells. 2) Determine whether MCPyV TAg expression is required for mouse MCC maintenance. 3) Examine the role of Merkel cell lineage transcription factors in governing neuroendocrine cell fate and biological behavior of human MCC cell lines. These studies will yield new insights into the molecular basis of MCC and validate a much-needed mouse model of MCC.

默克尔细胞癌(MCC)是一种罕见的侵袭性神经内分泌皮肤癌，常伴有 默克尔细胞多瘤病毒(MCPyV)的整合拷贝，并表达病毒转化抗原(TAG)， 可能在肿瘤的发生过程中起着关键作用。MCC肿瘤细胞也表达在正常、 存在于皮肤中的有丝分裂默克尔细胞，包括一组编码谱系特异性转录因子的mRNAs 牵涉到神经内分泌细胞的命运。我们实验室和其他实验室的工作证实了MCPyV小T抗原 (STAG)，+/-截短的大T抗原(TLTAg)，足以驱动体内转化，但MCC样蛋白 尽管标记靶向于各种潜在的肿瘤前体细胞，但在这些模型中均未检测到肿瘤。 缺乏可行的MCC小鼠模型一直是这一领域取得进展的主要障碍。 正常的默克尔细胞起源于特殊细胞间隔中的表皮祖细胞，称为触觉 圆顶，但MCC的起源细胞尚不清楚。努力推翻多个国家的明显阻力 MCPyV标签驱动的MCC发育的细胞类型，我们在基因工程小鼠中产生了 在表皮角质形成细胞中表达默克尔细胞转录因子Atoh1和MCPyV标签。 这些小鼠产生了少量增殖的MCC样肿瘤细胞，当与缺失结合时 根据多个标准，一个拷贝的p53产生的肉眼肿瘤与人类MCC惊人地相似。vt.给出 Atoh1在MCC肿瘤发生中的关键作用我们进行了补充性功能丧失研究，并 发现Atoh1基因敲除可以将人MCC细胞从典型的神经内分泌表型转化为 悬浮生长，细胞贴壁生长，神经内分泌标志物丢失，更具侵袭性 活体内的行为。 因此，我们假设Atoh1和其他决定默克尔细胞命运的转录因子起着关键作用 MCC的发病机制以及神经内分泌肿瘤表型的维持。我们建议 以下内容旨在验证这一假说。1)MCPyV标签驱动的MCC样瘤的建立和鉴定 靶向候选MCC祖细胞的表达。2)判断MCPyV标签表达式是否为 鼠标MCC维护所需。3)研究默克尔细胞系转录因子在 控制神经内分泌细胞的命运和人类MCC细胞系的生物学行为。这些研究将产生 对MCC的分子基础的新见解，并验证了MCC急需的小鼠模型。