title: A small molecule screening strategy with validation on human leukemia stem cells uncovers the therapeutic efficacy of kinetin riboside.
abstract: Gene regulatory networks that govern hematopoietic stem cells (HSCs) and leukemia-initiating cells (L-ICs) are deeply entangled. Thus, the discovery of compounds that target L-ICs while sparing HSC is an attractive but difficult endeavor. Presently, most screening approaches fail to counter-screen compounds against normal hematopoietic stem/progenitor cells (HSPCs). Here, we present a multistep in vitro and in vivo approach to identify compounds that can target L-ICs in acute myeloid leukemia (AML). A high-throughput screen of 4000 compounds on novel leukemia cell lines derived from human experimental leukemogenesis models yielded 80 hits, of which 10 were less toxic to HSPC. We characterized a single compound, kinetin riboside (KR), on AML L-ICs and HSPCs. KR demonstrated comparable efficacy to standard therapies against blast cells in 63 primary leukemias. In vitro, KR targeted the L-IC-enriched CD34(+)CD38(-) AML fraction, while sparing HSPC-enriched fractions, although these effects were mitigated on HSC assayed in vivo. KR eliminated L-ICs in 2 of 4 primary AML samples when assayed in vivo and highlights the importance of in vivo L-IC and HSC assays to measure function. Overall, we provide a novel approach to screen large drug libraries for the discovery of anti-L-IC compounds for human leukemias.
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sean P
authors.initials: SP
authors.lastname: McDermott
authors.forename: Kolja
authors.initials: K
authors.lastname: Eppert
authors.forename: Faiyaz
authors.initials: F
authors.lastname: Notta
authors.forename: Methvin
authors.initials: M
authors.lastname: Isaac
authors.forename: Alessandro
authors.initials: A
authors.lastname: Datti
authors.forename: Rima
authors.initials: R
authors.lastname: Al-Awar
authors.forename: Jeff
authors.initials: J
authors.lastname: Wrana
authors.forename: Mark D
authors.initials: MD
authors.lastname: Minden
authors.forename: John E
authors.initials: JE
authors.lastname: Dick
mesh_terms: D000241:Adenosine / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D000970:Antineoplastic Agents / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D007701:Kinetin / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D007938:Leukemia / Q000188:drug therapy* / Q000473:pathology*; D051379:Mice; D016688:Mice, Inbred NOD; D008819:Mice, Nude; D016513:Mice, SCID; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000473:pathology; D054852:Small Molecule Libraries / Q000032:analysis*; D016896:Treatment Outcome; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D054852:Small Molecule Libraries; C527965:kinetin riboside; D000241:Adenosine; D007701:Kinetin