Development of Small Molecule MEIS Inhibitors that modulate HSC activity

Abstract

<jats:title>Abstract</jats:title><jats:p><jats:italic>Meis1</jats:italic>, which belongs to TALE-type class of homeobox gene family, appeared as one of the key regulators of hematopoietic stem cell (HSC) self-renewal and a potential therapeutical target. However, small molecule inhibitors of MEIS1 remained unknown. This led us to develop inhibitors of MEIS1 that could modulate HSC activity. To this end, we have established a library of relevant homeobox family inhibitors and developed a high-throughput <jats:italic>in silico</jats:italic> screening strategy against homeodomain of MEIS proteins using the AutoDock Vina and PaDEL-ADV platform. We have screened over a million druggable small molecules <jats:italic>in silico</jats:italic> and selected putative MEIS inhibitors (MEISi) with no predicted cytotoxicity or cardiotoxicity. This was followed by <jats:italic>in vitro</jats:italic> validation of putative MEIS inhibitors using MEIS dependent luciferase reporter assays and analysis in the <jats:italic>ex vivo</jats:italic> HSC assays. We have shown that small molecules named MEISi-1 and MEISi-2 significantly inhibit MEIS-luciferase reporters <jats:italic>in vitro</jats:italic> and induce murine (LSKCD34<jats:sup>low</jats:sup> cells) and human (CD34<jats:sup>+</jats:sup>, CD133<jats:sup>+</jats:sup>, and ALDH<jats:sup>hi</jats:sup> cells) HSC self-renewal <jats:italic>ex vivo</jats:italic>. In addition, inhibition of MEIS proteins results in downregulation of <jats:italic>Meis1</jats:italic> and MEIS1 target gene expression including Hif-1α, Hif-2α and HSC quiescence modulators. MEIS inhibitors are effective <jats:italic>in vivo</jats:italic> as evident by induced HSC content in the murine bone marrow and downregulation of expression of MEIS target genes. These studies warrant identification of first-in-class MEIS inhibitors as potential pharmaceuticals to be utilized in modulation of HSC activity and bone marrow transplantation studies.</jats:p>

Mapping the native interaction surfaces of PREP1 with PBX1 by cross-linking mass-spectrometry and mutagenesis

“…It must be noticed that the use of the HXR9 in clinics has not been reported. Moreover, targeting the MEIS homeodomain by using small molecule derived from compound collections screenings seems effective 73 , but does not impair dimerization with PBX nor nuclear localization of MEIS.…”

BML‐260 promotes the growth of cord blood and mobilized peripheral blood hematopoietic stem and progenitor cells with improved reconstitution ability

“…No: P9172‐1G) and incubated at 37°C and 5% CO 2 for 15 min. Following the staining, the cells were analyzed by flow cytometry compared to DMSO control as we have done previously 26 . On the other hand, the human mPB‐CD34 + were seeded on 30 000 cells per well in the expansion medium.…”

Cell Biology Meets Cell Metabolism: Energy Production Is Similar in Stem Cells and in Cancer Stem Cells in Brain and Bone Marrow

“…79 Meis1 is in particular highly expressed in HSCs. 80 Meis1 regulates HSC metabolism and redox state by inducing HIF-1α and HIF-2α expression. 67 Meis1 is a transcription activator-like effector (TALE)-type transcription factor.…”

“…It cooperates with PBX1 and HOXA9 transcription factors to transactivate target genes such as those of HIF-1α and HIF-2α. 80 Knockdown of Meis1 causes downregulation of HIF-1 and HIF-2 activity with concomitant increased ROS levels and loss of HSC quiescence. 81 Meis1 levels are frequently upregulated in AML.…”

“…81 Meis1 levels are frequently upregulated in AML. 2,55,82 Recently, Turan et al 80 developed two small molecule Meis1 inhibitors to modulate HSC activity as Meis1 is a key regulator of HSCs. Meis1 inhibition downregulates HIF-1 and HIF-2 activity and reduces HSC quiescence.…”