Mechanisms of bone invasion and tumor growth in models of head and neck cancer.

描述(申请人提供)：头颈部鳞状细胞癌(HNSCC)通常侵犯骨骼，与严重的发病率和减少患者的生存有关。该项目的主要目标是通过识别和靶向肿瘤诱导的骨吸收机制来抑制HNSCC的骨侵袭和生长。这些研究将利用骨侵袭性HNSCC的体外和体内模型，使用来自自发性HNSCC肿瘤的人类细胞系。将检验以下总体假设：HNSCC侵袭骨是由肿瘤诱导的骨吸收和肿瘤衍生细胞因子表达的恶性循环引起的。特别是，HNSCC来源的甲状旁腺激素相关蛋白(PTHrP)和前列腺素E2(PGE2)诱导破骨细胞性骨吸收，从骨基质中释放转化生长因子-β(TGF-P)。转化生长因子-J3诱导额外的肿瘤合成PTHrP和PGE2，这是已知的支持肿瘤生长和骨吸收。此外，将骨吸收抑制剂唑来膦酸和环氧合酶-2抑制剂美洛昔康联合使用，将阻断恶性循环，减少骨侵袭和肿瘤生长。提出了三个具体目标。首先，确定细胞因子阻断是否会抑制HNSCC诱导的骨吸收。将通过测量基质细胞RANKL和OPG(破骨细胞活性的介质)的表达、破骨细胞前细胞的分化和骨培养中释放的转化生长因子-J3来评估骨吸收。PTHrP受siRNA抑制，PGE2受美洛昔康抑制。其次，研究骨吸收对HNSCC增殖及PTHrP和COX-2表达的影响。我们将比较溶骨和非溶骨条件培养液中和抗体中和转化生长因子-β的效果。第三，确定多模式治疗(唑来膦酸联合美洛昔康)在体内外对肿瘤生长和骨侵袭的影响。共培养将被用来确定在有骨存在的情况下，治疗对HNSCC增殖和凋亡的影响。体内肿瘤生长和骨侵袭将使用原位、异种移植的表达荧光素酶的HNSCC裸鼠模型来测量，并用体内生物发光成像和微型CT进行定量。HNSCC占头颈部癌症的90%以上，位居世界第六大常见癌症。在过去的30年里，患者的存活率并没有显著提高。骨侵犯常发生，且与预后较差有关。这项研究将确定同时抑制骨吸收和COX-2活性是否能成功阻止HNSCC模型的骨侵袭和减少肿瘤生长。

DESCRIPTION (provided by applicant): Squamous cell carcinoma of the head and neck (HNSCC) commonly invades bone, which is associated with severe morbidity and reduced patient survival. The primary objective of this project is to inhibit bone invasion and growth of HNSCC by identifying and targeting mechanisms of tumor-induced bone resorption. These investigations will utilize in vitro and in vivo models of bone-invasive HNSCC, employing human cell lines derived from spontaneous HNSCC tumors. The following overall hypothesis will be tested: HNSCC invasion into bone is caused by a vicious cycle of tumor-induced bone resorption and expression of tumor-derived cytokines. Specifically, HNSCC-derived parathyroid hormone-related protein (PTHrP) and prostaglandin E2 (PGE2) induce osteoclastic bone resorption which releases transforming growth factor-beta (TGF-P) from the bone matrix. TGF-J3 induces additional tumor-synthesis of PTHrP and PGE2 which are known to support tumor growth as well as bone resorption. Furthermore, combining a bone resorption inhibitor, zoledronic acid, with a cyclooxygenase-2 inhibitor, meloxicam, will block the vicious cycle and reduce bone invasion and tumor growth. Three specific aims are proposed. First, determine if cytokine blockade will inhibit HNSCC-induced bone resorption. Resorption will be evaluated by measuring stromal cell expression of RANKL and OPG (mediators of osteoclast activity), differentiation of pre-osteoclast cells, and TGF-J3 release from bone cultures. PTHrP will be reduced with siRNA, and PGE2 will be inhibited by meloxicam. Second, examine how bone resorption affects HNSCC proliferation and expression of PTHrP and COX-2. The effects of conditioned medium from lytic and non-lytic bone will be compared, with and without antibody neutralization of TGF-p. Third, determine the effect of multimodal therapy (zoledronic acid combined with meloxicam) on tumor growth and bone invasion in vitro and in vivo. Co-cultures will be used to determine the effect of treatment on HNSCC proliferation and apoptosis in the presence of bone. In vivo tumor growth and bone invasion will be measured using orthotopic, xenograft nude mouse models of luciferase-expressing HNSCC, quantitated with in vivo bioluminescent imaging and micro-CT. HNSCC represents over 90% of head and neck cancers, the 6th most common cancer in the world. Patient survival has not significantly improved over the past 30 years. Bone invasion frequently occurs and is associated with a poorer prognosis. This study will determine if simultaneous inhibition of bone resorption and COX-2 activity will successfully block bone invasion and reduce tumor growth in models of HNSCC.