title: Identification of apilimod as a first-in-class PIKfyve kinase inhibitor for treatment of B-cell non-Hodgkin lymphoma.
abstract: We identified apilimod as an antiproliferative compound by high-throughput screening of clinical-stage drugs. Apilimod exhibits exquisite specificity for phosphatidylinositol-3-phosphate 5-kinase (PIKfyve) lipid kinase and has selective cytotoxic activity in B-cell non-Hodgkin lymphoma (B-NHL) compared with normal cells. Apilimod displays nanomolar activity in vitro, and in vivo studies demonstrate single-agent efficacy as well as synergy with approved B-NHL drugs. Using biochemical and knockdown approaches, and discovery of a kinase domain mutation conferring resistance, we demonstrate that apilimod-mediated cytotoxicity is driven by PIKfyve inhibition. Furthermore, a critical role for lysosome dysfunction as a major factor contributing to apilimod's cytotoxicity is supported by a genome-wide CRISPR screen. In the screen,TFEB(master transcriptional regulator of lysosomal biogenesis) and endosomal/lysosomal genesCLCN7,OSTM1, andSNX10were identified as important determinants of apilimod sensitivity. These findings thus suggest that disruption of lysosomal homeostasis with apilimod represents a novel approach to treat B-NHL.
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Sophia
authors.initials: S
authors.lastname: Gayle
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Sean
authors.initials: S
authors.lastname: Landrette
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Neil
authors.initials: N
authors.lastname: Beeharry
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Chris
authors.initials: C
authors.lastname: Conrad
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Marylens
authors.initials: M
authors.lastname: Hernandez
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Paul
authors.initials: P
authors.lastname: Beckett
authors.affiliation: Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Yale University School of Medicine, New Haven, CT.
authors.forename: Shawn M
authors.initials: SM
authors.lastname: Ferguson
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Talya
authors.initials: T
authors.lastname: Mandelkern
authors.affiliation: Department of Cancer Pharmacology, Crown Bioscience Inc., Beijing, People's Republic of China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Howard Hughes Medical Institute, New Haven, CT; and.|Department of Genetics, Yale University School of Medicine, New Haven, CT.
authors.forename: Tian
authors.initials: T
authors.lastname: Xu
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rothberg
authors.affiliation: LAM Therapeutics, Guilford, CT.
authors.forename: Henri
authors.initials: H
authors.lastname: Lichenstein
mesh_terms: D000970:Antineoplastic Agents; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D004353:Drug Evaluation, Preclinical / Q000379:methods; D011992:Endosomes / Q000187:drug effects / Q000235:genetics; D057166:High-Throughput Screening Assays; D006801:Humans; D006835:Hydrazones; D016393:Lymphoma, B-Cell / Q000188:drug therapy*; D008247:Lysosomes / Q000187:drug effects / Q000235:genetics; D009025:Morpholines / Q000627:therapeutic use*; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D011743:Pyrimidines; D014227:Triazines / Q000627:therapeutic use*
chemical_list: D000970:Antineoplastic Agents; D006835:Hydrazones; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D014227:Triazines; C492139:PIKFYVE protein, human; C504227:apilimod