Modulation of Early Neutrophil Granulation: The Circulating Tumor Cell-Extravesicular Connection in Pancreatic Ductal Adenocarcinoma

Tumor cells dissociate from the primary site and enter into systemic circulation (circulating tu-mor cells, CTCs) either alone or Tumor cells dissociate from the primary site and enter into systemic circulation (circulating tu-mor cells, CTCs) either alone or as tumor microemboli (clusters); the latter having an increased predisposition towards forming distal metastases than single CTCs. The formation of clusters is, in part, created by contacts between cell–cell junction proteins and/or cytokine receptor pairs with other cells such as neutrophils, platelets, fibroblasts, etc. In the present study, we provide evidence for an extravesicular (EV) mode of communication between pancreatic cancer CTCs and neutrophils. Our results suggest that the EV proteome of CTCs contain signaling proteins that can modulate degranulation and granule mobilization in neutrophils and, also, contain tis-sue plasminogen activator and other proteins that can regulate cluster formation. By exposing naïve neutrophils to EVs isolated from CTCs, we further show how these changes are modulated in a dynamic fashion indicating evidence for a deeper EV based remodulatory effect on com-panion cells in clusters.as tumor microemboli (clusters); the latter having an increased predisposition towards forming distal metastases than single CTCs. The formation of clusters is, in part, created by contacts between cell–cell junction proteins and/or cytokine receptor pairs with other cells such as neutrophils, platelets, fibroblasts, etc. In the present study, we provide evidence for an extravesicular (EV) mode of communication between pancreatic cancer CTCs and neutrophils. Our results suggest that the EV proteome of CTCs contain signaling proteins that can modulate degranulation and granule mobilization in neutrophils and, also, contain tis-sue plasminogen activator and other proteins that can regulate cluster formation. By exposing naïve neutrophils to EVs isolated from CTCs, we further show how these changes are modulated in a dynamic fashion indicating evidence for a deeper EV based remodulatory effect on com-panion cells in clusters.

肿瘤细胞从原发灶脱离后，可单独或作为肿瘤微栓子（细胞簇）进入体循环，此类循环肿瘤细胞（circulating tumor cells, CTCs）中，以细胞簇形式存在的群体相较于单个CTCs，形成远端转移的倾向性更高。细胞簇的形成部分源于细胞-细胞连接蛋白和/或细胞因子受体对与中性粒细胞、血小板、成纤维细胞等其他细胞的相互接触。本研究为胰腺癌CTCs与中性粒细胞之间的细胞外囊泡（extracellular vesicle, EV）通讯模式提供了实验证据。研究结果显示，CTCs的EV蛋白质组含有可调控中性粒细胞脱颗粒及颗粒动员的信号蛋白，同时还包含组织型纤溶酶原激活物等可调控细胞簇形成的蛋白。通过将未受刺激的中性粒细胞暴露于CTCs来源的EV中，本研究进一步以动态方式揭示了上述调控过程，证明了EV对簇内伴随细胞存在更为深层次的重塑调控效应。