已知小的细胞外囊泡(sEV)从癌细胞释放,并通过与受体细胞的串扰促进癌症进展。我们以前报道过表达αVβ3整合素的sEV,一种在侵袭性神经内分泌前列腺癌(NEPrCa)中上调的蛋白质,有助于受体细胞的神经内分泌分化(NED)。这里,我们检查了αVβ3表达对sEV蛋白含量的影响,密度和功能。本研究中使用的sEV通过碘克沙醇密度梯度分离,并通过纳米粒子跟踪分析进行表征,免疫印迹和单囊泡分析。我们的含有αVβ3的sEV的蛋白质组学图谱显示,与对照sEV相比,参与凋亡和坏死的典型效应子的下调以及肿瘤细胞存活因子的上调。我们还表明,sEV中αVβ3的表达导致EV标志物的不同重新定位(Alix,CD81,CD9)到低密度sEV亚群。这种低密度重新定位不依赖于细胞外基质(ECM)蛋白与sEV的相互作用。这个sEV子集包含αVβ3和αVβ3下游效应子,NgR2,NEPrCa的新型标记。我们显示,与不表达αVβ3的sEV相比,含有αVβ3的sEV装载有更高量的NgR2。机械上,我们证明了含有NgR2的sEV不会影响sEV标记谱,但是当体内瘤内注射时,它们促进肿瘤生长并诱导NED。我们表明,表达NgR2的sEV增加了粘着斑激酶(FAK)的激活,已知的癌细胞增殖的启动子,在受体细胞中。我们还显示NgR2模拟含有αVβ3的sEV的作用,因为它在体内显示NgR2转染子的生长增加,与对照细胞相比。总的来说,我们的结果描述了货物发生的变化,含有αVβ3整合素及其效应子的癌细胞来源的sEV的密度和功能,NgR2,不影响sEV四跨膜蛋白谱。
It is known that small extracellular vesicles (sEVs) are released from cancer cells and contribute to cancer progression via crosstalk with recipient cells. We have previously reported that sEVs expressing the αVβ3 integrin, a protein upregulated in aggressive neuroendocrine prostate cancer (NEPrCa), contribute to neuroendocrine differentiation (NED) in recipient cells. Here, we examine the impact of αVβ3 expression on sEV protein content, density and function. sEVs used in this study were isolated by iodixanol density gradients and characterized by nanoparticle tracking analysis, immunoblotting and single vesicle analysis. Our proteomic profile of sEVs containing αVβ3 shows downregulation of typical effectors involved in apoptosis and necrosis and an upregulation of tumour cell survival factors compared to control sEVs. We also show that the expression of αVβ3 in sEVs causes a distinct reposition of EV markers (Alix, CD81, CD9) to a low-density sEV subpopulation. This low-density reposition is independent of extracellular matrix (ECM) protein interactions with sEVs. This sEV subset contains αVβ3 and an αVβ3 downstream effector, NgR2, a novel marker for NEPrCa. We show that sEVs containing αVβ3 are loaded with higher amounts of NgR2 as compared to sEVs that do not express αVβ3. Mechanistically, we demonstrate that sEVs containing NgR2 do not affect the sEV marker profile, but when injected in vivo intratumorally, they promote tumour growth and induce NED. We show that sEVs expressing NgR2 increase the activation of focal adhesion kinase (FAK), a known promoter of cancer cell proliferation, in recipient cells. We also show that NgR2 mimics the effect of sEVs containing αVβ3 since it displays increased growth of NgR2 transfectants in vivo, as compared to control cells. Overall, our results describe the changes that occur in cargo, density and functions of cancer cell-derived sEVs containing the αVβ3 integrin and its effector, NgR2, without affecting the sEV tetraspanin profiles.