Tumorigenicity-associated characteristics of human iPS cell lines

PLoS One. 2018 Oct 4;13(10):e0205022. doi: 10.1371/journal.pone.0205022. eCollection 2018.

Abstract

Human induced pluripotent stem cells (hiPSCs) represent promising raw materials of human cell-based therapeutic products (hCTPs). As undifferentiated hiPSCs exhibit intrinsic tumorigenicity properties that enable them to form teratomas, hCTPs containing residual undifferentiated hiPSCs may cause tumor formation following transplantation. We first established quantitative and sensitive tumorigenicity testing of hiPSCs dissociated into single cells using NOD/Shi-scid IL2Rγnull (NOG) mice by inhibiting apoptosis of hiPSCs with a Rho kinase inhibitor. To examine different features in tumorigenicity of various hiPSCs, 10 commonly available hiPSC lines were subjected to in vivo tumorigenicity testing. Transplanted hiPSC lines showed remarkable variation in tumor incidence, formation latency, and volumes. Most of the tumors formed were classified as immature teratomas. However, no signs of malignancies, such as carcinoma and sarcoma, were recognized in the tumors. Characteristics associated tumorigenicity of hiPSCs were investigated with microarray analysis, karyotype analysis, and whole exome sequencing. Gene expression profiling and pathway analysis supported different features of hiPSC lines in tumorigenicity. hiPSC lines showed chromosomal abnormalities in some lines and 61-77 variants of cancer-related genes carrying effective nonsynonymous mutations, which were confirmed in the COSMIC databases. In this study, the chromosomal abnormalities and cancer-related gene mutations observed in hiPSC lines did not lead to the malignancy of tumors derived from hiPSCs. Our results suggest that the potential tumorigenicity risk of hCTPs containing residual undifferentiated hiPSCs is dependent on not only amounts of undifferentiated hiPSCs but also features of the cell lines used as raw materials, a finding that should be considered from the perspective of quality of hCTPs used.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinogenesis* / genetics
  • Cell Line
  • Exome / genetics
  • Humans
  • Induced Pluripotent Stem Cells / pathology*
  • Karyotype
  • Transcriptome

Grants and funding

The present work was supported by a Research Grant from the Japanese Ministry of Health, Labour and Welfare (http://www.mhlw.go.jp/english/) (H25-JITSUYOKA(SAISEI)-IPPAN-008) and the Japan Agency for Medical Research and Development (https://www.amed.go.jp/en/) (15bk0104014h0103 to YS, 15bk0104014h0203 to SY, 16bk0104006h0104 to YS, 16bk0104006h0204 to SY, 17bk0104006j0105 to YS, and 17bk0104006j0205 to SY). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.