title: Structure-function correlation of G6, a novel small molecule inhibitor of Jak2: indispensability of the stilbenoid core.
abstract: Somatic mutations in the Jak2 protein, such as V617F, cause aberrant Jak/STAT signaling and can lead to the development of myeloproliferative neoplasms. This discovery has led to the search for small molecule inhibitors that target Jak2. Using structure-based virtual screening, our group recently identified a novel small molecule inhibitor of Jak2 named G6. Here, we identified a structure-function correlation of this compound. Specifically, five derivative compounds of G6 having structural similarity to the original lead compound were obtained and analyzed for their ability to (i) inhibit Jak2-V617F-mediated cell growth, (ii) inhibit the levels of phospho-Jak2, phospho-STAT3, and phospho-STAT5; (iii) induce apoptosis in human erythroleukemia cells; and (iv) suppress pathologic cell growth of Jak2-V617F-expressing human bone marrow cells ex vivo. Additionally, we computationally examined the interactions of these compounds with the ATP-binding pocket of the Jak2 kinase domain. We found that the stilbenoid core-containing derivatives of G6 significantly inhibited Jak2-V617F-mediated cell proliferation in a time- and dose-dependent manner. They also inhibited phosphorylation of Jak2, STAT3, and STAT5 proteins within cells, resulting in higher levels of apoptosis via the intrinsic apoptotic pathway. Finally, the stilbenoid derivatives inhibited the pathologic growth of Jak2-V617F-expressing human bone marrow cells ex vivo. Collectively, our data demonstrate that G6 has a stilbenoid core that is indispensable for maintaining its Jak2 inhibitory potential.
authors.affiliation: Department of Physiology and Functional Genomics, Laboratory Medicine, University of Florida College of Medicine, Gainesville, Florida 32610, USA.
authors.forename: Anurima
authors.initials: A
authors.lastname: Majumder
authors.forename: Lakshmanan
authors.initials: L
authors.lastname: Govindasamy
authors.forename: Andrew
authors.initials: A
authors.lastname: Magis
authors.forename: Róbert
authors.initials: R
authors.lastname: Kiss
authors.forename: Tímea
authors.initials: T
authors.lastname: Polgár
authors.forename: Rebekah
authors.initials: R
authors.lastname: Baskin
authors.forename: Robert W
authors.initials: RW
authors.lastname: Allan
authors.forename: Mavis
authors.initials: M
authors.lastname: Agbandje-McKenna
authors.forename: Gary W
authors.initials: GW
authors.lastname: Reuther
authors.forename: György M
authors.initials: GM
authors.lastname: Keseru
authors.forename: Kirpal S
authors.initials: KS
authors.lastname: Bisht
authors.forename: Peter P
authors.initials: PP
authors.lastname: Sayeski
mesh_terms: D019943:Amino Acid Substitution; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D053614:Janus Kinase 2 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D011087:Polycythemia Vera / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000235:genetics / Q000378:metabolism; D013267:Stilbenes / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D047428:Protein Kinase Inhibitors; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050799:STAT5 Transcription Factor; D013267:Stilbenes; C507924:JAK2 protein, human; D053614:Janus Kinase 2