title: Cytogenetic heterogeneity and their serial dynamic changes during acquisition of cytogenetic aberrations in cultured mesenchymal stem cells.
abstract: To minimize the risk of tumorigenesis in mesenchymal stem cells (MSCs), G-banding analysis is widely used to detect chromosomal aberrations in MSCs. However, a critical limitation of G-banding is that it only reflects the status of metaphase cells, which can represent as few as 0.01% of tested cells. During routine cytogenetic testing in MSCs, we often detect chromosomal aberrations in minor cell populations. Therefore, we aimed to investigate whether such a minority of cells can expand over time or if they ultimately disappear during MSC passaging. We passaged MSCs serially while monitoring quantitative changes for each aberrant clone among heterogeneous MSCs. To investigate the cytogenetic status of interphase cells, which represent the main population, we also performed interphase FISH analysis, in combination with G-banding and telomere length determination. In human adipose tissue-derived MSCs, 4 types of chromosomal aberrations were found during culturing, and in umbilical cord MSCs, 2 types of chromosomal aberrations were observed. Sequential dynamic changes among heterogeneous aberrant clones during passaging were similar to the dynamic changes observed in cancer stem cells during disease progression. Throughout all passages, the quantitative G-banding results were inconsistent with those of the interphase FISH analysis. Interphase FISH revealed hidden aberrations in stem cell populations with normal karyotypes by G-banding analysis. We found that telomere length gradually decreased during passaging until the point at which cytogenetic aberrations appeared. The present study demonstrates that rare aberrant clones at earlier passages can become predominant clones during later passages. Considering the risk of tumorigenesis due to aberrant MSCs, we believe that our results will help to establish proper safety guidelines for MSC use. In particular, we believe it is critical to test for chromosomal aberrations using both G-banding and FISH to ensure the safety of human stem cells that are manufactured in vitro for clinical applications.
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Kim
authors.affiliation: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyong Ok
authors.initials: KO
authors.lastname: Im
authors.affiliation: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Si Nae
authors.initials: SN
authors.lastname: Park
authors.affiliation: Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji Seok
authors.initials: JS
authors.lastname: Kwon
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Seon Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Laboratory of Immunology and Cancer Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea; Transplantation Research Institute, Seoul National University College of Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Keunhee
authors.initials: K
authors.lastname: Oh
authors.affiliation: Laboratory of Immunology and Cancer Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea; Transplantation Research Institute, Seoul National University College of Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Dong-Sup
authors.initials: DS
authors.lastname: Lee
authors.affiliation: Department of Biochemistry and Molecular Biology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Department of Biochemistry and Molecular Biology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Seong Who
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Lab of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Mi
authors.initials: M
authors.lastname: Jang
authors.affiliation: Lab of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Gene
authors.initials: G
authors.lastname: Lee
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Asthma Center and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Yeon-Mok
authors.initials: YM
authors.lastname: Oh
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Asthma Center and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Sang Do
authors.initials: SD
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: soonlee@snu.ac.kr.
authors.forename: Dong Soon
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects; D000818:Animals; D045744:Cell Line, Tumor; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D022202:Chromosomes, Artificial, Bacterial; D002999:Clone Cells; D036101:Cord Blood Stem Cell Transplantation; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase / Q000235:genetics; D007621:Karyotyping; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008677:Metaphase / Q000235:genetics; D051379:Mice; D016688:Mice, Inbred NOD; D016615:Telomere
keywords: Cytogenetic aberration; Fluorescence hybridization; Heterogeneity; Mesenchymal stem cells; Telomere