Novel NEK2 signaling pathways in myeloma progression - Bauer Diversity Supplement

项目摘要 多发性骨髓瘤(MM)是一种以广泛的结构和数字为特征的浆细胞恶性肿瘤 染色体异常。通过比较样本的连续基因表达谱(GEP) 在基线、强化化疗期间和复发时，我们发现了染色体不稳定(CIN)。 MM病预后不良的相关基因。CIN基因之一，丝氨酸苏氨酸激酶 NEK2基因是完全缓解(CR)患者骨髓瘤细胞中表达上调最显著的基因 微小残留病(MRD)和串联移植后化疗早期复发。 我们已经证明，对NEK2的药物或遗传抑制可以延缓肿瘤的生长并诱导细胞 骨髓瘤中的细胞凋亡和NEK2的高表达也与许多其他肿瘤的不良预后有关 癌症。去泛素酶(DUB)USP7稳定NEK2蛋白，导致核因子-2的激活。 κB/乙酰肝素酶途径，也参与骨破坏。然而，目前尚不清楚NEK2是否也 激活USP7。此外，我们还发现NEK2负性调节PD-L1的表达，很可能是通过 表观遗传修饰。高危骨髓瘤细胞显示PD-L1低水平表达，并对 免疫检查站封锁。因此，我们假设NEK2促进骨髓瘤细胞存活，药物 通过激活脱泛素酶USP7和组蛋白甲基转移酶而产生的抗性和疾病进展 EZH2.为了严格检验这一假设，我们将：(1)确定主要的去泛素化目标 通过Nek2-USP7复合体调节不同水平Nek2表达和表达的Nek2转基因小鼠 控制。我们将重点选择可能的蛋白质作为原则证明，以确定USP7作为 这个综合体中的信号中枢。(2)确定NEK2抑制免疫应答的机制 使用Nek2基因敲除小鼠和生化方法阻断骨髓瘤细胞中的检查点。以及，(3) 利用原代骨髓瘤细胞开发治疗耐药和复发骨髓瘤的新免疫疗法 基因Nek2基因敲除小鼠模型和骨髓瘤小鼠模型。由强劲的初步数据支持， 为这一应用提供了强有力的理论基础，拟议的研究有望促进新的、有针对性的 防治骨髓瘤进展和复发的方法。我们预测我们的结果 将延伸到骨髓瘤之外，也适用于其他血液学和实体肿瘤。

Project Summary Multiple Myeloma (MM) is a plasma cell malignancy characterized by extensive structural and numerical chromosomal abnormalities. By comparing consecutive gene expression profiles (GEP) of samples at baseline, during intensive chemotherapy, and at relapse, we have identified chromosomal instability (CIN) genes associated with poor prognosis in MM disease. One of the CIN genes, the serine-threonine kinase NEK2 is the most significantly upregulated gene in myeloma cells in patients in complete remission (CR) with minimal residual disease (MRD) and at relapse early during chemotherapy following tandem transplantations. We have shown that pharmacological or genetic inhibition of NEK2 delays tumor growth and induces cell apoptosis in myeloma and high expression of NEK2 has also been related to poor outcomes in many other cancers. The deubiquitinase (DUB) USP7 stabilizes NEK2 protein resulting in the activation of the NF- κB/heparanase pathway, also involved in bone destruction. However, it is unknown whether NEK2 also activates USP7. In addition, we have found that NEK2 negatively regulates PD-L1 expression, most likely via epigenetic modification. High-risk myeloma cells show low levels of PD-L1 expression and are resistant to immune checkpoint blockade. Therefore, we hypothesize that NEK2 promotes myeloma cell survival, drug resistance, and disease progression by activating the deubiquitinase USP7 and the histone methyltransferase EZH2. In order to rigorously test this hypothesis, we will: (1) Identify the major deubiquitination targets regulated by the Nek2-Usp7 complex using Nek2-transgenic mice with varying levels of Nek2 expression and controls. We will focus on selecting probable proteins as a proof-of-principle to establish the role of Usp7 as the signaling hub in this complex. (2) Determine the mechanisms by which NEK2 inhibits responses to immune checkpoint blockade in myeloma cells using Nek2-knockout mice and biochemical approaches. And, (3) Develop novel immune therapies for drug-resistant and relapsed myelomas using primary myeloma cells, a genetic Nek2-knockout mouse model, and a myeloma mouse model. Supported by strong preliminary data that provide a strong rationale for this application, the proposed research is poised to facilitate novel, targeted approaches to the prevention and treatment of myeloma progression and relapse. We predict that our results will extend beyond myeloma and also apply to other hematological and solid tumors.