title: Rab27A regulates exosome secretion from lung adenocarcinoma cells A549: involvement of EPI64.
abstract: Exosomes are small membrane vesicles secreted into the extracellular compartment by exocytosis. The unique composition of exosomes can be transported to other cells which allow cells to exert biological functions at distant sites. However, in lung cancer, the regulation of exosome secretion was poorly understood. In this study, we employed human lung adenocarcinoma A549 cells to determine the exosome secretion and involved regulation mechanism. We found that Rab27A was expressed in A549 cells and the reduction of Rab27A by Rab27A-specific shRNA could significantly decrease the secretion of exosome by A549 cells. EPI64, a candidate GAP that is specific for Rab27, was also detected in A549 cells. By pull-down assay, we found that EPI64 participated in the exosome secretion of A549 cells by acting as a specific GAP for Rab27A, not Rab27B. Overexpression of EPI64 enhanced exosome secretion. Taken together, in A549 cells, EPI64 could regulate the exosome secretion by functioning as a GAP specific for Rab27A.
authors.affiliation: Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, 710038, China.
authors.forename: Wenhai
authors.initials: W
authors.lastname: Li
authors.forename: Yunsheng
authors.initials: Y
authors.lastname: Hu
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.forename: Yong
authors.initials: Y
authors.lastname: Han
authors.forename: Guoliang
authors.initials: G
authors.lastname: Han
authors.forename: Jiakuan
authors.initials: J
authors.lastname: Chen
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Li
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D000077192:Adenocarcinoma of Lung; D045744:Cell Line, Tumor; D055354:Exosomes / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism*; D000075745:rab27 GTP-Binding Proteins
chemical_list: D020690:GTPase-Activating Proteins; D034741:RNA, Small Interfering; C425805:TBC1D10A protein, human; D000075745:rab27 GTP-Binding Proteins; C066694:RAB27A protein, human; D020691:rab GTP-Binding Proteins
keywords: A549cells; EPI64; GAP; Lung cancer; Rab27A; exosome secretion