title: Co-option of Liver Vessels and Not Sprouting Angiogenesis Drives Acquired Sorafenib Resistance in Hepatocellular Carcinoma.
abstract: The anti-angiogenic Sorafenib is the only approved systemic therapy for advanced hepatocellular carcinoma (HCC). However, acquired resistance limits its efficacy. An emerging theory to explain intrinsic resistance to other anti-angiogenic drugs is 'vessel co-option,' ie, the ability of tumors to hijack the existing vasculature in organs such as the lungs or liver, thus limiting the need for sprouting angiogenesis. Vessel co-option has not been evaluated as a potential mechanism for acquired resistance to anti-angiogenic agents.
  
  
  
  To study sorafenib resistance mechanisms, we used an orthotopic human HCC model (n = 4-11 per group), where tumor cells are tagged with a secreted protein biomarker to monitor disease burden and response to therapy. Histopathology, vessel perfusion assessed by contrast-enhanced ultrasound, and miRNA sequencing and quantitative real-time polymerase chain reaction were used to monitor changes in tumor biology.
  
  
  
  While sorafenib initially inhibited angiogenesis and stabilized tumor growth, no angiogenic 'rebound' effect was observed during development of resistance unless therapy was stopped. Instead, resistant tumors became more locally infiltrative, which facilitated extensive incorporation of liver parenchyma and the co-option of liver-associated vessels. Up to 75% (±10.9%) of total vessels were provided by vessel co-option in resistant tumors relative to 23.3% (±10.3%) in untreated controls. miRNA sequencing implicated pro-invasive signaling and epithelial-to-mesenchymal-like transition during resistance development while functional imaging further supported a shift from angiogenesis to vessel co-option.
  
  
  
  This is the first documentation of vessel co-option as a mechanism of acquired resistance to anti-angiogenic therapy and could have important implications including the potential therapeutic benefits of targeting vessel co-option in conjunction with vascular endothelial growth factor receptor signaling.
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Kuczynski
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Melissa
authors.initials: M
authors.lastname: Yin
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Avinoam
authors.initials: A
authors.lastname: Bar-Zion
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Christina R
authors.initials: CR
authors.lastname: Lee
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Henriett
authors.initials: H
authors.lastname: Butz
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Shan
authors.initials: S
authors.lastname: Man
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Frances
authors.initials: F
authors.lastname: Daley
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Peter B
authors.initials: PB
authors.lastname: Vermeulen
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: George M
authors.initials: GM
authors.lastname: Yousef
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: F Stuart
authors.initials: FS
authors.lastname: Foster
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Reynolds
authors.affiliation: Affiliations of authors: Department of Medical Biophysics, University of Toronto, Toronto, Canada (EAK, FSF, RSK); Physical Sciences Platform (MY, FSF) and Biological Sciences Platform (CRL, SM, RSK), Sunnybrook Research Institute, Toronto, Canada; Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa, Israel (ABZ); Keenan Research Centre, St. Michael's Hospital, Toronto, Canada (HB, GMY); The Breast Cancer Now Toby Robins Research Centre, Mary-Jean Mitchell Green Building, The Institute of Cancer Research, London, UK (FD, PBV, ARR); Translational Cancer Research Unit, GZA Hospitals St. Augustinus, Antwerp, Belgium (PBV).
authors.forename: Robert S
authors.initials: RS
authors.lastname: Kerbel
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001808:Blood Vessels / Q000000981:diagnostic imaging / Q000473:pathology; D006528:Carcinoma, Hepatocellular / Q000098:blood supply* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D003287:Contrast Media; D004195:Disease Models, Animal; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D008099:Liver / Q000098:blood supply*; D008113:Liver Neoplasms / Q000098:blood supply* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D008297:Male; D051379:Mice; D016513:Mice, SCID; D035683:MicroRNAs / Q000032:analysis; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000517:prevention & control; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000627:therapeutic use; D053495:Osteopontin / Q000097:blood; D010671:Phenylurea Compounds / Q000627:therapeutic use*; D012097:Repressor Proteins / Q000235:genetics; D017423:Sequence Analysis, RNA; D015398:Signal Transduction / Q000235:genetics; D000077157:Sorafenib; D014463:Ultrasonography; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000097:blood; D014746:Vimentin / Q000235:genetics; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1 / Q000235:genetics
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D018952:Antigens, CD34; D000970:Antineoplastic Agents; D003287:Contrast Media; D018398:Homeodomain Proteins; D035683:MicroRNAs; D010671:Phenylurea Compounds; D012097:Repressor Proteins; C506896:Spp1 protein, mouse; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D014746:Vimentin; C492363:ZEB2 protein, human; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1; C467480:vascular endothelial growth factor A, mouse; D053495:Osteopontin; D009536:Niacinamide; D000077157:Sorafenib