The Role of Egfl6 in Tumor Immunity

卵巢癌(OvCa)死亡率极高，显然需要新的治疗方法。 接近了。一种这样的方法是免疫检查点抑制(ICI)治疗。不幸的是，尽管 在许多卵巢癌患者中存在抗肿瘤效应细胞，ICI疗法在卵巢癌中的应答率较低。 其中一个原因可能是大量免疫抑制髓系来源的抑制细胞(MDSCs)和 卵巢中存在肿瘤相关巨噬细胞(TAMs)。美赞臣和都是负向调节免疫 在癌症和治疗方法中，可以扰乱这些细胞的招募/功能可以增强ICI 回应。干扰多药耐药干细胞/的潜在治疗靶点是Egfl6。Egfl6是一种发育生长因子 它被认为可以调节细胞的迁移、增殖和分化，并且在OvCa中高表达。 我们发现过度表达Egf6的小鼠的粒细胞和单核细胞数量都增加了。 骨髓(BM)和脾。Egfl6治疗骨髓髓系细胞与整合素相关 P-Syk依赖性增加，并分化为IL-10+和S100A9+粒细胞MDSC。小鼠肿瘤 与对照相比，(1)MDSC积累量和M2- 像一样，(Iii)表达与中性粒细胞胞外陷阱(Net)相关的CXCL2和CLEC5a 形成，以及(Iii)对ICI治疗难治。因此，我们假设Egfl6通过Syk激活促进了一种 在肿瘤中通过增加骨髓间充质干细胞/及其Net的产生而抑制TME。作为一种 延伸到这一点，我们假设抑制Egfl6将增强ICI治疗的疗效。测试我们的 假设：SA1。探讨髓系细胞Egfl6信号转导中对Syk的需求。作为系统 是粒细胞整合素信号转导所必需的，我们假设靶向干扰Syk将阻止Egfl6- 依赖粒细胞堆积。使用特定的Syk抑制剂化合物和Syk-KO 粒细胞/单核细胞，我们将剖析Egfl6-Syk调节轴。SA2.试析Egfl6在NETS中的作用 ICI治疗的形成和耐药性。我们发现表达Egfl6的肿瘤水平升高，并出现网状感染 Egfl6诱导CXCL2和CLEC5a，这两个与NETsis相关的因子。这两种情况下都会发生 以及缺乏ICI治疗。我们假设Egfl6通过Net的诱导，限制了抗肿瘤免疫 提高对ICI治疗的抵抗力。我们将使用CXCL2和CLEC5a介导的抑制/KO方法来 明确Egfl6诱导蚊媒中毒的机制以及Egfl6诱导的蚊媒中毒对ICI细胞毒作用的影响 豁免权。评估Egfl6中和抗体对ICI治疗和抗肿瘤疗效的影响 豁免权。我们将使用免疫活性ICI反应的小鼠OvCa模型来评估 Egfl6中和抗体，以克服Egfl6介导的免疫抑制。综合这些研究将 OvCa介导的肿瘤免疫抑制新机制的研究及EGFL6抗体的验证 一种新的治疗方法，以加强卵巢癌患者的ICI治疗。

Ovarian cancer (OvCa) has an extremely high mortality rate, indicating a clear need for new therapeutic approaches. One such approach is immune checkpoint inhibitor (ICI) therapy. Unfortunately, despite the presence of anti-tumor effector cells in many OvCa patients, ICI therapies have poor response rates in OvCa. One reason for this may large numbers of immunosuppressive myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) present in the OvCa. Both MDSC and TAM negatively regulate immunity in cancer and therapeutic approaches which can disrupt the recruitment/function of these cells can enhance ICI response. A potential therapeutic target to disrupt MDSC/TAM is Egfl6. Egfl6 is a developmental growth factor which is known to regulate cellular migration, proliferation, and differentiation and is highly expressed in OvCa. We found that mice which overexpress Egfl6 have increased numbers of granulocytes and monocytes in both the bone marrow (BM) and spleen. Egfl6 treatment of BM myeloid cells was associated with an integrin dependent increase in p-Syk, and differentiation to IL-10+ and S100A9+ granulocytic MDSC. Murine tumors which overexpress Egfl6, compared to controls, (i) have a significant increase in MDSC accumulation and M2- like TAM, (iii) express CXCL2 and CLEC5a, factors associated with neutrophil extracellular traps (NETs) formation, and (iii) are refractory to ICI therapy. We thus hypothesize that Egfl6, via Syk activation, promotes an immunosuppressive TME by increasing numbers of MDSC/TAM and their production of NETs in tumors. As an extension of this, we hypothesize that inhibition of Egfl6, will enhance the efficacy of ICI therapy. To test our hypotheses, we propose: SA1. To evaluate the requirement for Syk in Egfl6 signaling on myeloid cells. As Syk is required for integrin signaling in granulocytes, we hypothesize that targeted disruption of Syk will prevent Egfl6- dependent granulocyte accumulation. Using specific Syk inhibitor compounds and Syk-KO granulocytes/monocytes, we will dissect the Egfl6-Syk regulatory axis. SA2. To analyze the role of Egfl6 in NETs formation and resistance to ICI therapy. We found Egfl6 expressing tumors have increased levels and NETosis and that Egfl6 induces CXCL2 and CLEC5a, factors associated with NETosis. This occurs both in the presence and absence of ICI therapy. We hypothesize that Egfl6, by induction of NETs, limits the anti-tumor immunity promoting resistance to ICI therapy. We will use CXCL2 and CLEC5a mediated inhibition/KO approaches to define the mechanisms by which Egfl6 induces NETosis and the impact of Egfl6 induced NETosis on ICI cytotoxic immunity. SA 3. Evaluate the impact of Egfl6 neutralizing antibody on the efficacy of ICI therapy and anti-tumor immunity. We will use an immune competent ICI responsive murine OvCa model to evaluate the ability of an Egfl6 neutralizing antibody to overcome Egfl6 mediated immune suppression. Combined these studies will characterize a novel mechanism of OvCa mediated tumor immune suppression and validate EGFL6 antibody as a novel therapeutic approach to enhance ICI therapy in OvCa patients.