Targeting ligand-independent CSF3R dimerization in chronic neutrophilic leukemia

碳水化合物对蛋白质的修饰，称为糖基化，在癌症中通常是调节失调的。一 慢性中性粒细胞白血病(CNL)就是一个例子，这是一种罕见的疾病，其特征是 中性粒细胞。超过80%的已发表的CNL病例是由集落刺激因子3受体突变引起的 (CSF3R)。这种突变导致O-连接糖基化减少以及配体非依赖性增加 二聚化。然而，这两个发现之间的关系尚不清楚，也没有治疗方法 锁定突变的表位。这个项目的中心假设是糖基化的丧失减少了立体结构 阻碍CSF3R二聚化，并揭示了靶向治疗的癌症特异性表位。在目标1中，质量 光谱分析将识别野生型蛋白上存在但突变变体中缺失的多糖。 此外，突变的CSF3R的晶体结构将揭示糖基化缺失如何重塑受体 界面，并促进配体无关的二聚化。在目标2中，酵母展示蛋白的筛选将 确定与突变的但不是野生型CSF3R结合的候选基因。针对突变蛋白的生物制剂将 在体外被验证为标记细胞和阻断二聚体，并选择性地消除癌细胞 CNL小鼠模型。结合起来，这项工作将展示如何理解 糖基化有助于药物的发现。这项工作是由詹妮弗博士在斯坦福大学共同赞助的 Cochran和Carolyn Bertozzi分别是蛋白质工程和糖生物学领域的领导者。这个项目也是 通过与最先发现CSF3R突变的Julia Maxson博士的合作得到支持。这位博士 工作将为研究生涯提供必要的培训，弥合分子机制之间的差距 癌症和药物开发。

The modification of proteins with carbohydrates, called glycosylation, is commonly dysregulated in cancer. One example is chronic neutrophilic leukemia (CNL), a rare disease characterized by the uncontrolled growth of neutrophils. Over 80% of published CNL cases result from a mutation in the colony-stimulating factor 3 receptor (CSF3R). This mutation results in decreased O-linked glycosylation as well as increased ligand-independent dimerization. However, the relationship between these two findings is not known and there are no therapies that target the mutated epitope. The central hypothesis of this project is the loss of glycosylation decreases steric hindrance for CSF3R dimerization and reveals a cancer-specific epitope for targeted therapy. In Aim 1, mass spectrometry will identify the glycans that are present on the wild-type protein but missing in the mutated variant. Additionally, crystal structures of mutant CSF3R will reveal how the loss of glycosylation remodels the receptor interface and promotes ligand-independent dimerization. In Aim 2, screens of yeast-displayed proteins will identify candidates which bind to mutated, but not wild-type CSF3R. Biologics specific to the mutated protein will be validated for labeling cells and blocking dimerization in vitro, and selectively eliminating cancer cells in a mouse model of CNL. Combined, this work will demonstrate how understanding the structural effects of glycosylation facilitates drug discovery. This work is co-sponsored at Stanford University by Drs. Jennifer Cochran and Carolyn Bertozzi, leaders in protein engineering and glycobiology, respectively. This project is also supported through a collaboration with Dr. Julia Maxson, who first discovered the CSF3R mutation. This doctoral work will provide essential training for a research career, bridging the gap between molecular mechanisms of cancer and drug development.