title: Cotransplantation of mouse embryonic stem cells and bone marrow stromal cells following spinal cord injury suppresses tumor development.
abstract: Embryonic stem (ES) cells are a potential source for treatment of spinal cord injury (SCI). Although one of the main problems of ES cell-based cell therapy is tumor formation, there is no ideal method to suppress tumor development. In this study, we examined whether transplantation with bone marrow stromal cells (BMSCs) prevented tumor formation in SCI model mice that received ES cell-derived grafts containing both undifferentiated ES cells and neural stem cells. Embryoid bodies (EBs) formed in 4-day hanging drop cultures were treated with retinoic acid (RA) at a low concentration of 5 x 10(-9) M for 4 days, in order to allow some of the ES cells to remain in an undifferentiated state. RA-treated EBs were enzymatically digested into single cells and used as ES cell-derived graft cells. Mice transplanted with ES cell-derived graft cells alone developed tumors at the grafted site and behavioral improvement ceased after day 21. In contrast, no tumor development was observed in mice cotransplanted with BMSCs, which also showed sustained behavioral improvement. In vitro results demonstrated the disappearance of SSEA-1 expression in cytochemical examinations, as well as attenuated mRNA expressions of the undifferentiated markers Oct3/4, Utf1, Nanog, Sox2, and ERas by RT-PCR in RA-treated EBs cocultured with BMSCs. In addition, MAP2-immunopositive cells appeared in the EBs cocultured with BMSCs. Furthermore, the synthesis of NGF, GDNF, and BDNF was confirmed in cultured BMSCs, while immunohistochemical examinations demonstrated the survival of BMSCs and their maintained ability of neurotrophic factor production at the grafted site for up to 5 weeks after transplantation. These results suggest that BMSCs induce undifferentiated ES cells to differentiate into a neuronal lineage by neurotrophic factor production, resulting in suppression of tumor formation. Cotransplantation of BMSCs with ES cell-derived graft cells may be useful for preventing the development of ES cell-derived tumors.
authors.affiliation: Department of Neurosurgery, Nara Medical University, Nara 634-8521, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Matsuda
authors.forename: Masahide
authors.initials: M
authors.lastname: Yoshikawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Kimura
authors.forename: Yukiteru
authors.initials: Y
authors.lastname: Ouji
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakase
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Nishimura
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Nonaka
authors.forename: Hayato
authors.initials: H
authors.lastname: Toriumi
authors.forename: Shuichi
authors.initials: S
authors.lastname: Yamada
authors.forename: Mariko
authors.initials: M
authors.lastname: Nishiofuku
authors.forename: Kei
authors.initials: K
authors.lastname: Moriya
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Ishizaka
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Nakamura
authors.forename: Toshisuke
authors.initials: T
authors.lastname: Sakaki
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D016026:Bone Marrow Transplantation / Q000379:methods*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D053595:Embryonic Stem Cells; D007150:Immunohistochemistry; D051379:Mice; D009369:Neoplasms / Q000473:pathology*; D009414:Nerve Growth Factors / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013119:Spinal Cord Injuries / Q000473:pathology / Q000628:therapy*; D033581:Stem Cell Transplantation / Q000379:methods*; D013234:Stem Cells / Q000166:cytology* / Q000473:pathology; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism / Q000637:transplantation
chemical_list: D009414:Nerve Growth Factors