Abstract PR001: Cancer stem cells as origin of tumor associated immune cells

Abstract Development of cancer stem cell (CSC) models from induced pluripotent stem cells (iPSCs) for different types of cancers will help to investigate the tumorigenesis and tumor microenvironment heterogeneity. In this context, our lab have developed a novel method to generate CSCs from iPSCs under cancer microenvironment using conditioned medium from different cancer cell lines. On the other hand, the ability of CSCs to exhibit different hematopoietic cells is still unclear. In our previous study, BT549 cell line conditioned media was used to obtain CSCs. CSCs (miPSCs-BT) converted from mouse iPSCs were tumorigenic and expressed stemmens and cancer stem cell markers. CSCs converted from miPSCs and injected into mice were used. CSCs isolated from malignant tumor were cultured in absence of Leukemia Inhibitory Factor(LIF) where undifferentiated cells were selected using puromycin. Non-adherent cells (NACs) arising from adherent CSCs collected and their viability, the morphology and the expression of hematopoietic cell markers were investigated. NACs were also injected into the tail vein of busulfan conditioned Balb/c nude mice. CSCs were also induced to differentiate into macrophages while using IL3 and SCF. The round nucleated NACs were viable, positive for hematopoietic lineage markers and had CD34 positive subpopulation as well as the ability of homing to the bone marrow. Moreover, after 4 weeks of injection, Wright-Giemsa staining showed that the number of white blood cells was higher in injected mice with NACs comparing to the control. CSCs also showed the ability to differentiate toward macrophages. In conclusion, CSCs were demonstrated to have the potential to provide progenies with hematopoietic markers, morphology, and homing ability to the bone marrow, which could give new insight into the tumor microenvironment according to the plasticity of CSCs. This abstract is also being presented as PO057. Citation Format: Ghmkin Hassan, Said M. Afify, Akimasa Seno, Masaharu Seno. Cancer stem cells as origin of tumor associated immune cells [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2020 Oct 19-20. Philadelphia (PA): AACR; Cancer Immunol Res 2021;9(2 Suppl):Abstract nr PR001.