title: Tumor-Free Transplantation of Patient-Derived Induced Pluripotent Stem Cell Progeny for Customized Islet Regeneration.
abstract: Human induced pluripotent stem cells (iPSCs) and derived progeny provide invaluable regenerative platforms, yet their clinical translation has been compromised by their biosafety concern. Here, we assessed the safety of transplanting patient-derived iPSC-generated pancreatic endoderm/progenitor cells. Transplantation of progenitors from iPSCs reprogrammed by lentiviral vectors (LV-iPSCs) led to the formation of invasive teratocarcinoma-like tumors in more than 90% of immunodeficient mice. Moreover, removal of primary tumors from LV-iPSC progeny-transplanted hosts generated secondary and metastatic tumors. Combined transgene-free (TGF) reprogramming and elimination of residual pluripotent cells by enzymatic dissociation ensured tumor-free transplantation, ultimately enabling regeneration of type 1 diabetes-specific human islet structures in vivo. The incidence of tumor formation in TGF-iPSCs was titratable, depending on the oncogenic load, with reintegration of the cMYC expressing vector abolishing tumor-free transplantation. Thus, transgene-free cMYC-independent reprogramming and elimination of residual pluripotent cells are mandatory steps in achieving transplantation of iPSC progeny for customized and safe islet regeneration in vivo.
  
  
  CONCLUSIONS
  Pluripotent stem cell therapy for diabetes relies on the safety as well as the quality of derived insulin-producing cells. Data from this study highlight prominent tumorigenic risks of induced pluripotent stem cell (iPSC) products, especially when reprogrammed with integrating vectors. Two major underlying mechanisms in iPSC tumorigenicity are residual pluripotent cells and cMYC overload by vector integration. This study also demonstrated that combined transgene-free reprogramming and enzymatic dissociation allows teratoma-free transplantation of iPSC progeny in the mouse model in testing the tumorigenicity of iPSC products. Further safety assessment and improvement in iPSC specification into a mature β cell phenotype would lead to safe islet replacement therapy for diabetes.
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Moustafa M
authors.initials: MM
authors.lastname: El Khatib
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Seiga
authors.initials: S
authors.lastname: Ohmine
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Egon J
authors.initials: EJ
authors.lastname: Jacobus
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Tonne
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Salma G
authors.initials: SG
authors.lastname: Morsy
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Holditch
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Claire A
authors.initials: CA
authors.lastname: Schreiber
authors.affiliation: Laboratory of Animal Health and Hygiene, Department of Biological Production Science, College of Agriculture, Ibaraki University, Ibaraki, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Uetsuka
authors.affiliation: PRESTO, Japan Science and Technology Agency, Saitama, Japan Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Noemi
authors.initials: N
authors.lastname: Fusaki
authors.affiliation: Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Wigle
authors.affiliation: Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USA Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Andre
authors.initials: A
authors.lastname: Terzic
authors.affiliation: Division of Endocrinology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Yogish C
authors.initials: YC
authors.lastname: Kudva
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA ikeda.yasuhiro@mayo.edu.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D000067470:Cellular Reprogramming Techniques; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis / Q000378:metabolism / Q000601:surgery*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis / Q000601:surgery*; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors; D064593:Heterografts; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism / Q000473:pathology / Q000637:transplantation*; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D016381:Islets of Langerhans Transplantation / Q000009:adverse effects / Q000379:methods*; D015603:Keratinocytes / Q000378:metabolism / Q000473:pathology / Q000637:transplantation*; D016086:Lentivirus / Q000235:genetics; D008297:Male; D016513:Mice, SCID; D010641:Phenotype; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D012038:Regeneration; D018243:Teratocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D014162:Transfection
chemical_list: D007328:Insulin; C489427:MYC protein, human; D016271:Proto-Oncogene Proteins c-myc
keywords: Insertional mutagenesis; Integration; Teratoma; Type 1 diabetes; iPS cells