CLA as a Mediator of Human Prostate Tumor Metastasis

描述（由申请人提供）：人类前列腺肿瘤细胞向骨的迁移是一个转移过程，优先发生于前列腺肿瘤向其他远处部位的转移。最近的研究结果表明，与其他组织的血管内皮细胞粘附相比，人前列腺肿瘤细胞对人骨髓内皮（BMEC）具有增强的粘附能力。人类前列腺肿瘤细胞粘附分子在血流（剪切应力）下，在迁移到骨髓之前，启动血管内与人BMEC的结合尚不清楚。选择素是一类细胞粘附分子，在剪切应力下介导细胞粘附相互作用，由于内皮(E)-选择素在人BMEC上组成性表达，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，并导致骨髓中的细胞优先沉积。我们已经获得了初步的证据表明，来源于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在功能和结构上似乎与白细胞上表达的CLA相同。由于CLA表达对白细胞进入骨至关重要，我们假设CLA在侵袭性前列腺肿瘤细胞向骨的迁移中也起重要作用。本研究的目的是确定CLA是否为人骨转移性前列腺肿瘤细胞上的主要e-选择素配体，并研究一种新型CLA合成抑制剂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室方法比较和对比候选e-选择素配体，包括CLA，在人骨转移性前列腺肿瘤细胞中表达，并分析在剪切应力条件下4-F-GIcNAc对前列腺肿瘤细胞粘附人BMEC的影响。此外，我们将采用小鼠自发性前列腺肿瘤转移模型来研究4-F-GIcNAc在体内预防骨转移的作用。这些研究将有助于揭示e -选择素配体（即CLA）在介导人前列腺肿瘤细胞向骨迁移中的重要性，并促进新型抗转移疗法的发展，如4-F-GIcNAc。

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.