CLA as a Mediator of Human Prostate Tumor Metastasis

描述（由申请人提供）：人前列腺肿瘤细胞迁移至骨是一种转移过程，优先于前列腺肿瘤转移至其他远端部位。最近的研究结果表明，人前列腺肿瘤细胞表现出增强的粘附能力，人骨髓内皮细胞（BMEC）相比，细胞粘附血管内皮细胞在其他组织。人前列腺肿瘤细胞粘附分子在迁移到骨髓之前在血流（剪切应力）下启动与人BMEC的血管内结合是未知的。选择素是一类在剪切应力下介导细胞粘附相互作用的细胞粘附分子，并且由于内皮（E）-选择素在人BMEC上组成型表达，我们假设人前列腺肿瘤细胞上的E-选择素配体有助于启动对BMEC的粘附并导致骨髓中的优先细胞沉积。我们已经获得的初步证据表明，来自骨转移的人前列腺肿瘤细胞系表达白细胞E-选择素配体，皮肤淋巴细胞相关抗原（CLA）。令人惊讶的是，骨转移性前列腺肿瘤细胞上表达的CLA似乎在功能和结构上与白细胞上的CLA相同。由于CLA的表达是白细胞进入骨的关键，我们假设，CLA也发挥了重要作用，在侵袭性的人前列腺肿瘤细胞迁移到骨。本研究的目的是确定CLA是否是人骨转移性前列腺肿瘤细胞上的主要E-选择素配体，研究CLA合成的新型抑制剂4-F-GIcNAc是否会阻止人前列腺肿瘤细胞与BMEC E-选择素结合并干扰人前列腺肿瘤骨转移。因此，我们将利用平行板流动室方法学来比较和对比由人骨转移性前列腺肿瘤细胞表达的候选E-选择素配体（包括CLA），并分析在剪切应力条件下4-F-GlcNAc对前列腺肿瘤细胞粘附于人BMEC的影响。此外，我们将采用自发性人前列腺肿瘤转移的小鼠模型来研究4-F-GlcNAc在预防骨转移中的体内功效。这些研究将有助于揭示E-选择素配体（S），即CLA，在介导人前列腺肿瘤细胞向骨迁移中的重要性，并刺激新型抗转移治疗剂（如4-F-GlcNAc）的开发。

DESCRIPTION (provided by applicant): Migration of human prostate tumor cells to bone is a metastatic process that occurs preferentially to prostate tumor metastasis to other distant sites. Recent findings suggest that human prostate tumor cells exhibit augmented adhesive capabilities to human bone marrow endothelium (BMEC) compared with cell adhesion to vascular endothelium in other tissues. Human prostate tumor cell adhesion molecules that initiate intravascular binding to human BMEC under blood flow (shear stress) prior to emigration into bone marrow are unknown. The selectins are a class of cell adhesion molecules that mediate cell adhesion interactions under shear stress, and since endothelial (E)-selectin is constitutively expressed on human BMEC, we hypothesize that E-selectin ligand(s) on human prostate tumor cells help initiate adhesion to BMEC and cause preferential cell lodgement in the bone marrow. We have obtained preliminary evidence showing that a human prostate tumor cell line derived from bone metastases expresses the leukocyte E-selectin ligand, cutaneous lymphocyte-associated antigen (CLA). Surprisingly, CLA expressed on bone-metastatic prostate tumor cells appears to be functionally and structurally identical to CLA on leukocytes. Since CLA expression is critical for leukocyte entry into bone, we hypothesize that CLA also plays an important role in migration of aggressive human prostate tumor cells to bone. The objectives of this proposal are to establish whether CLA is the principal E-selectin ligand on human bone-metastatic prostate tumor cells, to investigate whether 4-F-GIcNAc, a novel inhibitor of CLA synthesis, will prevent human prostate tumor cell binding to BMEC E-selectin and interfere with human prostate tumor metastasis to bone. Accordingly, we will utilize parallel-plate flow chamber methodology to compare and contrast candidate E-selectin ligand(s), including CLA, expressed by human bone-metastatic prostate tumor cells and analyze the effects of 4-F-GIcNAc on prostate tumor cell adhesion to human BMEC under shear stress conditions. Furthermore, we will employ a mouse model of spontaneous human prostate tumor metastasis to investigate in vivo efficacy of 4-F-GIcNAc in preventing bone metastasis. These studies will help reveal the importance of E-selectin ligand(s), namely CLA, in mediating the migration of human prostate tumor cells to bone and stimulate the development of novel anti-metastatic therapeutics, such 4-F-GIcNAc.