Hypoxia and HIF in Sarcomagenesis

描述(申请人提供)：软组织肉瘤是来源于肌肉、结缔组织和软骨的间充质细胞的实体瘤。恶性纤维组织细胞瘤(MFH)是肉瘤中最具侵袭性和最常见的亚型，具有高度转移性。肿瘤内低氧被认为促进肉瘤转移，包括MFH，转移到远处。然而，这一过程的分子基础尚不清楚。最近，低氧诱导因子(HIF)11及其几个转录靶点，包括转录因子FOXM1，已被基因芯片分析确定为转移性MFH肉瘤的标志物。FOXM1的表达调控在肉瘤中可能特别重要，因为FOXM1与许多其他人类癌症的肿瘤形成和转移有关。HIF和FOXM1都是RAS途径的潜在下游效应因子，在多达50%的MFH肿瘤中发现了RAS突变。这一建议的中心假设是HIF活性在低氧肉瘤中增加，促进FOXM1的表达和转移。基于这一假设，我将追求三个具体目标。目的1：探讨缺氧和缺氧诱导因子对肉瘤细胞增殖、凋亡和衰老的影响及其分子机制。具体目的2：明确低氧、低氧诱导的迁移/侵袭和氧化应激反应在肉瘤细胞系中的作用及其分子基础。具体目标3：利用可诱导的小鼠肉瘤和人类异种移植瘤模型，研究HIFs和FOXM1在体内的作用。为了完成这些研究，我将结合细胞生物学、生物化学、免疫组织化学、遗传学和动物模型的体外和体内方法。本研究的目的是阐明低氧和HIF依赖的肉瘤形成和发展的潜在机制。这些研究的长期目标将是确定新的治疗靶点，这将促进肉瘤的新治疗，并提供关于一般肿瘤形成和肺部转移的重要线索。 公共卫生相关性：MFH是50-70岁成年人中最常见的肉瘤类型。它也是最具侵袭性的肉瘤类型，五年存活率只有24%。目前肉瘤的治疗方法有手术、放疗和化疗。然而，这种疾病的靶向治疗是有限的，因为它在分子水平上的特征很差。也没有专门针对转移性肉瘤细胞的治疗方法。因此，我建议研究肉瘤的形成和发展的机制，以促进靶向治疗的发展。

DESCRIPTION (provided by applicant): Soft tissue sarcomas are solid tumors derived from mesenchymal cells of muscle, connective tissue, and cartilage. Malignant fibrous histiocytoma (MFH), the most aggressive and most commonly diagnosed subtype of sarcoma is highly metastatic. Intratumoral hypoxia has been proposed to facilitate metastasis of sarcomas, including MFH, to distant sites. However, the molecular basis of this process is unknown. Recently, hypoxia inducible factor (HIF)11 and several of its transcriptional targets, including the transcription factor FOXM1, have been identified as markers of metastatic MFH sarcoma by microarray analysis. Regulation of FOXM1 expression may be particularly important in sarcomas, as FOXM1 has been associated with tumor formation and metastasis in numerous other human cancers. Both HIF and FOXM1 are potential downstream effectors of the Ras pathway and Ras mutations are found in up to 50% of MFH tumors. The central hypothesis of this proposal is that HIF activity is increased in hypoxic sarcomas, promoting expression of FOXM1 and metastasis. Based on this hypothesis I will pursue three specific aims. Specific Aim 1: To determine the effects and underlying molecular mechanisms of hypoxia and HIF on proliferation, apoptosis, and senescence of sarcoma cell lines in vitro. Specific Aim 2: To define the effects and molecular basis of hypoxia and HIF- mediated migration/invasion and oxidative stress responses in sarcoma cell lines. Specific Aim 3: To examine the role of HIFs and FOXM1 in vivo using an inducible mouse model of sarcoma and human xenograft tumors. To complete these studies I will combine in vitro and in vivo methods of cell biology, biochemistry, immunohistochemistry, genetics, and animal modeling. The objective of this research proposal is to elucidate the underlying mechanisms of hypoxia and HIF-dependent sarcoma formation and progression. The long-term goal of these studies will be to identify novel therapeutic targets, which will facilitate new treatments for sarcoma and provide important clues about general tumor formation and metastasis to the lung. PUBLIC HEALTH RELEVANCE: MFH is the most commonly diagnosed type of sarcoma in adults ages 50 -70. It is also the most aggressive type of sarcoma and has a five-year survival rate of only 24%. The current treatments for sarcoma are surgery, radiation, and chemotherapy. However, targeted treatments for this disease are limited because it is poorly characterized at the molecular level. There are also no treatments that specifically target metastatic sarcoma cells. Therefore, I propose to investigate the mechanisms of sarcoma formation and progression in order to facilitate the development of targeted therapeutics.