Tumor exosomes induce tunneling nanotubes in lipid raft-enriched regions of human mesothelioma cells.
Tunneling nanotubes (TnTs) are long, non-adherent, actin-based cellular extensions that act as conduits for transport of cellular cargo between connected cells. The mechanisms of nanotube formation and the effects of the tumor microenvironment and cellular signals on TnT formation are unknown. In the present study, we explored exosomes as potential mediators of TnT formation in mesothelioma and the potential relationship of lipid rafts to TnT formation. Mesothelioma cells co-cultured with exogenous mesothelioma-derived exosomes formed more TnTs than cells cultured without exosomes within 24-48 h; and this effect was most prominent in media conditions (low-serum, hyperglycemic medium) that support TnT formation (1.3-1.9-fold difference). Fluorescence and electron microscopy confirmed the purity of isolated exosomes and revealed that they localized predominantly at the base of and within TnTs, in addition to the extracellular environment. Time-lapse microscopic imaging demonstrated uptake of tumor exosomes by TnTs, which facilitated intercellular transfer of these exosomes between connected cells. Mesothelioma cells connected via TnTs were also significantly enriched for lipid rafts at nearly a 2-fold higher number compared with cells not connected by TnTs. Our findings provide supportive evidence of exosomes as potential chemotactic stimuli for TnT formation, and also lipid raft formation as a potential biomarker for TnT-forming cells.
Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN 55455, USA.
Venugopal
V
Thayanithy
Moore Laboratory, Department of Cell Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Victor
V
Babatunde
Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, University of Minnesota, Minneapolis, MN 55455, USA.
Elizabeth L
EL
Dickson
Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN 55455, USA.
Phillip
P
Wong
Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Sanghoon
S
Oh
Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Xu
X
Ke
Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Afsar
A
Barlas
Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Sho
S
Fujisawa
Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Yevgeniy
Y
Romin
Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
André L
AL
Moreira
Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Robert J
RJ
Downey
Departments of Medicine and Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA.
Clifford J
CJ
Steer
Department of Surgery, University of Minnesota, Minneapolis, MN 55455, USA.
Subbaya
S
Subramanian
Molecular Cytology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Katia
K
Manova-Todorova
Moore Laboratory, Department of Cell Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Malcolm A S
MAS
Moore
Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: emil-lou@umn.edu.
Emil
E
Lou
D001692:Biological Transport / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology*; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D055354:Exosomes / Q000378:metabolism*; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism*; D008654:Mesothelioma / Q000378:metabolism*; D043942:Nanotubes; D015398:Signal Transduction; D059016:Tumor Microenvironment
Exosomes; Intercellular communication; Intercellular transfer; Lipid rafts; Mesothelioma; Tunneling nanotubes