title: Enhanced shedding of extracellular vesicles from amoeboid prostate cancer cells: potential effects on the tumor microenvironment.
abstract: The gene encoding the cytoskeletal regulator DIAPH3 is lost at high frequency in metastatic prostate cancer, and DIAPH3 silencing evokes a transition to an amoeboid tumor phenotype in multiple cell backgrounds. This amoeboid transformation is accompanied by increased tumor cell migration, invasion, and metastasis. DIAPH3 silencing also promotes the formation of atypically large (> 1 μm) membrane blebs that can be shed as extracellular vesicles (EV) containing bioactive cargo. Whether loss of DIAPH3 also stimulates the release of nano-sized EV (e.g., exosomes) is not established. Here we examined the mechanism of release and potential biological functions of EV shed from DIAPH3-silenced and other prostate cancer cells. We observed that stimulation of LNCaP cells with the prostate stroma-derived growth factor heparin-binding EGF-like growth factor (HB-EGF), combined with p38MAPK inhibition caused EV shedding, a process mediated by ERK1/2 hyperactivation. DIAPH3 silencing in DU145 cells also increased rates of EV production. EV isolated from DIAPH3-silenced cells activated AKT1 and androgen signaling, increased proliferation of recipient tumor cells, and suppressed proliferation of human macrophages and peripheral blood mononuclear cells. DU145 EV contained miR-125a, which suppressed AKT1 expression and proliferation in recipient human peripheral blood mononuclear cells and macrophages. Our findings suggest that EV produced as a result of DIAPH3 loss or growth factor stimulation may condition the tumor microenvironment through multiple mechanisms, including the proliferation of cancer cells and suppression of tumor-infiltrating immune cells.
authors.affiliation: Division of Cancer Biology and Therapeutics; Departments of Surgery, Pathology and Laboratory Medicine, and Biomedical Sciences; Samuel Oschin Comprehensive Cancer Institute; Cedars-Sinai Medical Center; Los Angeles, CA USA; Urological Diseases Research Center; Boston Children's Hospital; Boston, MA USA; Department of Surgery; Harvard Medical School; Boston, MA USA.
authors.forename: Jayoung
authors.initials: J
authors.lastname: Kim
authors.affiliation: Urological Diseases Research Center; Boston Children's Hospital; Boston, MA USA; Department of Surgery; Harvard Medical School; Boston, MA USA.
authors.forename: Samantha
authors.initials: S
authors.lastname: Morley
authors.affiliation: Program in Cellular and Molecular Medicine; Boston Children's Hospital; Harvard Medical School; Boston, MA USA.
authors.forename: Minh
authors.initials: M
authors.lastname: Le
authors.affiliation: Division of Immunology; Boston Children's Hospital; Harvard Medical School; Boston, MA USA.
authors.forename: Denis
authors.initials: D
authors.lastname: Bedoret
authors.affiliation: Division of Immunology; Boston Children's Hospital; Harvard Medical School; Boston, MA USA.
authors.forename: Dale T
authors.initials: DT
authors.lastname: Umetsu
authors.affiliation: Division of Cancer Biology and Therapeutics; Departments of Surgery, Pathology and Laboratory Medicine, and Biomedical Sciences; Samuel Oschin Comprehensive Cancer Institute; Cedars-Sinai Medical Center; Los Angeles, CA USA; Urological Diseases Research Center; Boston Children's Hospital; Boston, MA USA; Department of Surgery; Harvard Medical School; Boston, MA USA.
authors.forename: Dolores
authors.initials: D
authors.lastname: Di Vizio
authors.affiliation: Division of Cancer Biology and Therapeutics; Departments of Surgery, Pathology and Laboratory Medicine, and Biomedical Sciences; Samuel Oschin Comprehensive Cancer Institute; Cedars-Sinai Medical Center; Los Angeles, CA USA; Urological Diseases Research Center; Boston Children's Hospital; Boston, MA USA; Department of Surgery; Harvard Medical School; Boston, MA USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Freeman
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000728:Androgens / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D055252:Cell-Derived Microparticles / Q000473:pathology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D000080865:Formins; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D059016:Tumor Microenvironment / Q000276:immunology / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000728:Androgens; C484571:DIAPH3 protein, human; D000080865:Formins; C531888:MIRN125 microRNA, human; D035683:MicroRNAs; C494918:AKT1 protein, human; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: AKT1; EMT; amoeboid; extracellular vesicles; immune cells; miR125a; microvesicles; prostate cancer