Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden.
Department of Oncology-Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden.
J Extracell Vesicles. 2016 Mar 7;5:29877. doi: 10.3402/jev.v5.29877. eCollection 2016.
Epithelial cells lining the prostate acini release, in a regulated manner (exocytosis), nanosized vesicles called prostasomes that belong to the exosome family. Prostate cancer cells have preserved this ability to generate and export exosomes to the extracellular space. We previously demonstrated that human prostasomes have an ATP-forming capacity. In this study, we compared the capacity of extracellular vesicles (EVs) to generate ATP between normal seminal prostasomes and exosomes secreted by PC3 cells (PC3 exosomes), a prostate cancer cell line. Proteomic analyses identified enzymes of the glycolytic chain in both prostasomes and PC3 exosomes, and we found that both of them were capable of generating ATP when supplied with substrates. Notably, the net production of extracellular ATP was low for prostasomes due to a high ATPase activity contrary to an elevated net ATP level for PC3 exosomes because of their low ATPase activity. The uptake of the 2 types of EVs by normal prostate epithelial cells (CRL2221) and prostate cancer cells (PC3) was visualized and measured, demonstrating differential kinetics. Interestingly, this uptake was dependent upon an ongoing glycolytic flux involving extracellular ATP formation by EVs and/or intracellular ATP produced from the recipient cells. We conclude that the internalization of EVs into recipient cells is an energy-requiring process also demanding an active V-ATPase and the capacity of EVs to generate extracellular ATP may play a role in this process.
前列腺腺泡衬里的上皮细胞以受调控的方式（胞吐作用）释放纳米级囊泡，称为前列腺小体，属于外泌体家族。前列腺癌细胞保留了生成和向细胞外空间输出外泌体的能力。我们之前证明了人类前列腺小体具有生成 ATP 的能力。在这项研究中，我们比较了正常精液前列腺小体和 PC3 细胞（PC3 外泌体）分泌的外泌体生成 ATP 的能力，PC3 细胞是一种前列腺癌细胞系。蛋白质组学分析鉴定了前列腺小体和 PC3 外泌体中糖酵解链的酶，我们发现它们都能够在供应底物时生成 ATP。值得注意的是，由于 ATP 酶活性高，前列腺小体产生的细胞外 ATP 净产量低，而由于其 ATP 酶活性低，PC3 外泌体产生的细胞外 ATP 净水平较高。通过正常前列腺上皮细胞（CRL2221）和前列腺癌细胞（PC3）可视化和测量了 2 种 EV 的摄取，表明存在差异动力学。有趣的是，这种摄取依赖于持续的糖酵解通量，涉及 EV 生成细胞外 ATP 和/或来自受者细胞的细胞内 ATP。我们得出结论，EV 进入受体细胞的内化是一个需要能量的过程，也需要活跃的 V-ATPase，并且 EV 生成细胞外 ATP 的能力可能在这个过程中发挥作用。
