Validating the eCyPA/CD147 signaling complex for myeloma therapy

 描述（由申请人提供）： 背景：多发性骨髓瘤（MM）是一种在骨髓（BM）中积聚的浆细胞癌症。尽管治疗方法最近取得了进展，但它仍然无法治愈，迫切需要新颖且更有效的疗法。然而，最近出现了一种新的治疗模式，该模式通过破坏 BM 微环境（“土壤”）对 MM 细胞（“种子”）的趋向性，有望改善患者的治疗结果。由于 BM 血管生成是 MM 进展的一个标志，与疾病阶段相关，因此很明显，在 MM 细胞和 BM 微环境之间的相互作用中，那些具有 BM 内皮细胞 (BMEC) 的细胞必定在 MM 进展中发挥重要作用。初步数据：在研究 MM 细胞与 BM 微环境的相互作用过程中，我们发现了经典 Wnt 信号传导的关键作用，它是细胞间通讯和趋向性的管道，最终导致促迁移、增殖和存活基因的转录激活。 Wnt 信号传导的末端效应器是一种转录复合物，其中包括另外两种信号传导蛋白：β-连环蛋白和 BCL9。此外，在使用 BM 组织微阵列进行免疫组织化学研究期间，我们观察到 BMEC 中受限且高水平的 BCL9 表达，但其他 BM 细胞中未观察到。此外，通过蛋白质组学分析，我们发现细胞外亲环蛋白 A (eCyPA) 是 Wnt/ß-catenin/BCL9 复合物的下游转录靶标，该复合物由 BMEC 分泌，但其他 BM 基质细胞不分泌，并促进 MM 中的多效性信号传导变化，包括增强 eCyPA 受体 CD14 的表达。此外，敲除 BMEC 中的 eCyPA 或 MM 细胞中的 CD147 显着降低 MM 细胞的迁移和增殖。工作假设：(i) BMEC 发出的信号对于 MM 进展至关重要； (ii) eCyPA 在 BMEC 的信号输出中发挥关键作用，调节 MM 细胞的迁移、侵袭、定植、生长、存活和耐药性。因此，靶向 MM 细胞上的 eCyPA 与其同源受体 CD147 之间的相互作用可治疗 MM，特别是对于对标准化疗具有获得性耐药的病例。目标：(i) 进一步表征 BMEC 在 MM 进展中的作用，(ii) 验证 eCyPA/CD147 信号复合物作为 MM 治疗靶点的作用，(iii) 识别和功能表征 BMEC 分泌的促进 MM 进展的其他信号分子，以及 (iii) 开发高通量筛选试验来识别 eCyPA/CD147 相互作用的小分子抑制剂，以用于未来开发 MM 靶向疗法。预期结果：i) 验证 eCyPA/CD147 信号复合物作为 MM 治疗的有效无毒靶标的作用； ii) 鉴定 MM 进展的新型潜在生物标志物和治疗靶点。对医学的更广泛影响：针对表达 CD147 并“归巢”于 BM 的 MM 和其他血液恶性肿瘤开发更有效的靶向疗法。

 DESCRIPTION (provided by applicant): Background: Multiple Myeloma (MM) is a cancer of plasma cells that accumulate in the bone marrow (BM). Despite recent advances in treatments, it remains incurable and there is urgent need of novel and more effective therapies. However, there has recently surfaced a new treatment paradigm that shows great promise to improve patient outcome by disrupting the tropism that the BM microenvironment, the `soil', plays on MM cells, the `seeds'. Since BM angiogenesis is a hallmark of MM progression that correlates with disease stage, it became evident that among the interactions between MM cells and the BM microenvironment, those with BM endothelial cells (BMECs) must play an important role in MM progression. Preliminary data: During studies of the interaction of MM cells with the BM microenvironment, we uncovered a critical role of canonical Wnt signaling, a conduit for cell-cell communication and tropism culminating in transcriptional activation of pro- migration, proliferation, and survival genes. The terminal effector of Wnt signaling is a transcriptional complex that includes two other signaling proteins, ß-catenin and BCL9. Moreover, during immunohistochemical studies using BM tissue microarrays, we observed restricted and high-level BCL9 expression in BMECs but not other BM cells. In addition, using proteomic analysis we have documented that extracellular Cyclophilin A (eCyPA) is a downstream transcriptional target of the Wnt/ß-catenin/BCL9 complex, which is secreted by BMECs but not other BM stromal cells and promote pleiotropic signaling changes in MM including enhanced expression of CD14, the know receptor of eCyPA. Furthermore, knockdown of either eCyPA in BMECs or CD147 in MM cells markedly decreased migration and proliferation of MM cells. Working hypothesis: (i) signaling from BMECs is essential for MM progression; (ii) eCyPA plays critical roles in the signaling output from BMECs that modulate migration, invasion, colonization, growth, survival, and drug resistance of MM cells. Thus, targeting the interaction between eCyPA and its cognate receptor CD147 on MM cells is therapeutic for MM, particularly for cases with acquired resistance to standard chemotherapy. Goals: (i) to further characterize the role of BMECs in MM progression, (ii) to validate the role of the eCyPA/CD147 signaling complex as therapeutic target for MM, (iii) to identify and functionally characterize additional signaling molecules secreted by BMECs that promote MM progression, and (iii) to develop a high throughput screening assay to identify small molecule inhibitors of eCyPA/CD147 interaction for future development of targeted therapies for MM. Expected results: i) validate role of eCyPA/CD147 signaling complex as effective nontoxic target for MM therapy; ii) identification of novel potential biomarkers of MM progression and therapeutic targets. Broader implications for medicine: Development of more effective targeted therapies for MM and other hematologic malignancies that express CD147 and 'home in' the BM.