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

描述（由申请人提供）：头颈部鳞状细胞癌（HNSCC）通常侵袭骨，这与严重的发病率和患者生存率降低有关。本研究的主要目的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。这些研究将利用体外和体内骨侵袭性HNSCC模型，采用来自自发性HNSCC肿瘤的人细胞系。将检验以下总体假设：HNSCC侵入骨是由肿瘤诱导的骨吸收和肿瘤源性细胞因子表达的恶性循环引起的。具体而言，HNSCC衍生的甲状旁腺相关蛋白（PTHrP）和前列腺素E2（PGE 2）诱导骨细胞骨吸收，其从骨基质释放转化生长因子-β（TGF-β）。TGF-β 3诱导PTHrP和PGE 2的额外肿瘤合成，已知PTHrP和PGE 2支持肿瘤生长以及骨吸收。此外，将骨吸收抑制剂唑来膦酸与环氧合酶-2抑制剂美洛昔康联合使用，将阻断恶性循环并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RANKL和OPG（破骨细胞活性介质）的基质细胞表达、破骨细胞前体细胞的分化和骨培养物中TGF-β 3的释放来评价吸收。siRNA可降低PTHrP，美洛昔康可抑制PGE 2。其次，研究骨吸收如何影响HNSCC增殖和PTHrP和考克斯-2的表达。将比较溶解性和非溶解性骨的条件培养基的作用，有和没有抗体中和TGF-β。第三，确定多模式治疗（唑来膦酸联合美洛昔康）对体外和体内肿瘤生长和骨侵袭的作用。将使用共培养物来确定在骨存在的情况下处理对HNSCC增殖和凋亡的影响。将使用表达端粒酶的HNSCC的原位异种移植裸鼠模型测量体内肿瘤生长和骨侵袭，用体内生物发光成像和micro-CT定量。HNSCC占头颈部癌症的90%以上，是世界上第六大最常见的癌症。在过去的30年里，患者的生存率没有显著提高。骨侵犯经常发生，并且与较差的预后相关。本研究将确定同时抑制骨吸收和考克斯-2活性是否将成功阻断骨侵袭并减少HNSCC模型中的肿瘤生长。

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.