title: Exosomal HIF1α supports invasive potential of nasopharyngeal carcinoma-associated LMP1-positive exosomes.
abstract: It has emerged recently that exosomes are potential carriers of pro-tumorigenic factors that participate in oncogenesis. However, whether oncogenic transcription factors are transduced by exosomes is unknown. Hypoxia-inducible factor-1α (HIF1α) transcriptionally regulates numerous key aspects of tumor development and progression by promoting a more aggressive tumor phenotype, characterized by increased proliferation and invasiveness coupled with neoangiogenesis. It has been shown that the principal oncoprotein of Epstein-Barr virus (EBV), latent membrane protein 1 (LMP1), drives oncogenic processes and tumor progression of the highly invasive EBV malignancy, nasopharyngeal carcinoma (NPC). We now demonstrate that endogenous HIF1α is detectable in exosomes and that LMP1 significantly increases levels of HIF1α in exosomes. HIF1 recovered from exosomes retains DNA-binding activity and is transcriptionally active in recipient cells after exosome uptake. We also show that treatment of EBV-negative cells with LMP1-exosomes increases migration and invasiveness of NP cell lines in functional assays, which correlates with the phenotype associated with epithelial-mesenchymal transition (EMT). In addition, we provide evidence that HIF1α itself participates in exosome-mediated pro-metastatic effects in recipient cells, as exosome-mediated delivery of active and inactive forms of HIF1α results in reciprocal changes in the expression of E- and N-cadherins associated with EMT. Further, immunohistochemical analysis of NPC tumor tissues revealed direct correlation between protein levels of LMP1 and of the endosome/exosome marker tetraspanin, CD63, which suggests an increase in exosome formation in this EBV-positive malignancy. We hypothesize that exosome-mediated transfer of functional pro-metastatic factors by LMP1-positive NPC cells to surrounding tumor cells promotes cancer progression.
authors.affiliation: 1] Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA [2] Division of Otolaryngology, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Aga
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Bentz
authors.affiliation: Dipartimento di Medicina Clinica e Molecolare, Università di Roma La Sapienza, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Raffa
authors.affiliation: Dipartimento di Medicina Clinica e Molecolare, Università di Roma La Sapienza, Rome, Italy.
authors.forename: M R
authors.initials: MR
authors.lastname: Torrisi
authors.affiliation: Division of Otolaryngology, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kondo
authors.affiliation: Division of Otolaryngology, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Wakisaka
authors.affiliation: Division of Otolaryngology, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yoshizaki
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Pagano
authors.affiliation: 1] Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA [2] Department of Cell Biology and Physioligy, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: J
authors.initials: J
authors.lastname: Shackelford
mesh_terms: D002277:Carcinoma; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D004247:DNA / Q000737:chemistry; D058750:Epithelial-Mesenchymal Transition; D055354:Exosomes / Q000378:metabolism; D057809:HEK293 Cells; D004854:Herpesvirus 4, Human / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010641:Phenotype; D011485:Protein Binding; D060149:Tetraspanin 30 / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000378:metabolism*; D014945:Wound Healing
chemical_list: C554586:CD63 protein, human; C037662:EBV-associated membrane antigen, Epstein-Barr virus; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D060149:Tetraspanin 30; D014763:Viral Matrix Proteins; D004247:DNA