Multisite studies for validation and improvement of a highly efficient culture assay for detection of undifferentiated human pluripotent stem cells intermingled in cell therapy products

• Published in: Cytotherapy (Oxford, England) Vol. 23; no. 2; pp. 176 - 183
• Main Authors: Watanabe, Takeshi, Yasuda, Satoshi, Kusakawa, Shinji, Kuroda, Takuya, Futamura, Mayumi, Ogawa, Mitsuhide, Mochizuki, Hidemi, Kikkawa, Eri, Furukawa, Hatsue, Nagaoka, Masato, Sato, Yoji
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.02.2021
• Subjects: cell therapy products; detection sensitivity; multisite experiments; pluripotent stem cells; standardization; tumorigenicity; standardization; tumorigenicity; pluripotent stem cells; cell therapy products; multisite experiments; detection sensitivity
• ISSN: 1465-3249; 1477-2566
• DOI: 10.1016/j.jcyt.2020.07.009

The Multisite Evaluation Study on Analytical Methods for Non-Clinical Safety Assessment of Human-Derived Regenerative Medical Products (MEASURE) is a Japanese experimental public–private partnership initiative, which aims to standardize methodology for tumorigenicity evaluation of human pluripotent stem cell (hPSC)-derived cell therapy products (CTPs). Undifferentiated hPSCs possess tumorigenic potential, and thus residual undifferentiated hPSCs are one of the major hazards for the risk of tumor formation from hPSC-derived CTPs. Among currently available assays, a highly efficient culture (HEC) assay is reported to be one of the most sensitive for the detection of residual undifferentiated hPSCs. MEASURE first validated the detection sensitivity of HEC assay and then investigated the feasibility of magnetic-activated cell sorting (MACS) to improve sensitivity. The multisite experiments confirmed that the lower limit of detection under various conditions to which the human induced pluripotent stem cell lines and culture medium/substrate were subjected was 0.001%. In addition, MACS concentrated cells expressing undifferentiated cell markers and consequently achieved a detection sensitivity of 0.00002%. These results indicate that HEC assay is highly sensitive and robust and that the application of MACS on this assay is a promising tool for further mitigation of the potential tumorigenicity risk of hPSC-derived CTPs.