The effect of imidazoquinoxaline agent EAPB0503 on the proliferation and differentiation potential of mesenchymal stem cells

Abstract

Background and purpose: The imidazoquinoxaline compound EAPB0503, an analogue of imiquimod, exhibits anti-tumor properties against various types of leukemias. However, the impact of EAPB0503 on non-cancerous cells, particularly mesenchymal stem cells (MSCs), is not well-elucidated. Numerous studies highlight the interplay between MSCs and leukemic cells within the bone marrow (BM) niche, influencing leukemogenesis and the development of drug resistance. Building on previous research, this study investigates the influence of EAPB0503 on MSCs derived from the bone marrow, specifically examining its effects on proliferation and differentiation potential. Method: In this research, the impact of EAPB0503 on an in vitro model of bone marrow-derived mesenchymal stem cells (BM-MSCs) was examined. The assessment focused on the cells' survival and their ability to differentiate into the osteogenic lineage after treatment with EAPB0503, assessed through staining with alkaline phosphatase and Alizarin Red S. Additionally, the study analyzed stemness and osteogenic markers in BM-MSCs, including N cadherin, connexin 43 (Cx43), alkaline phosphatase (ALP), NFκB, β-Catenin, and Snail, using various techniques such as quantitative real-time PCR (qPCR), Western blot, and immunofluorescence. Results: EAPB0503 at the concentration of 0.1 µM did not have any major effects on cell proliferation and cell number and osteogenic differentiation at the phenotypic and at the molecular level. However, at a higher concentration (0.5 µM), EAPB0503 reduced cell proliferation and induced morphological changes. In addition, it compromised osteogenic differentiation by downregulating osteogenic markers at transcript and protein levels Conclusion: EAPB0503 does not seem to compromise healthy non-cancer cells, namely BM-MSCs. This is of particular importance in leukemia treatment research; as EAPB0503 has proven effective against leukemic cells and given the tight interplay between hematopoietic cells (such as leukemic cells) and MSCs in the BM niche. More work is underway to determine the effect of EAPB0503 in co-culture systems of leukemia cells and MSCs