title: Energy-requiring uptake of prostasomes and PC3 cell-derived exosomes into non-malignant and malignant cells.
abstract: 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.
authors.affiliation: Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Karl Göran
authors.initials: KG
authors.lastname: Ronquist
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden.
authors.forename: Claire
authors.initials: C
authors.lastname: Sanchez
authors.affiliation: Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Louise
authors.initials: L
authors.lastname: Dubois
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Chioureas
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden.
authors.forename: Pedro
authors.initials: P
authors.lastname: Fonseca
authors.affiliation: Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Larsson
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Ullén
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Yachnin
authors.affiliation: Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Ronquist
authors.affiliation: Department of Oncology-Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden; theoharis.panaretakis@ki.se.
authors.forename: Theocharis
authors.initials: T
authors.lastname: Panaretakis
keywords: ATPase; energy metabolism; exosome uptake; exosomes; extracellular ATP; extracellular vesicles; glycolysis; prostasomes; prostate cancer