title: A screen for Fli-1 transcriptional modulators identifies PKC agonists that induce erythroid to megakaryocytic differentiation and suppress leukemogenesis.
abstract: The ETS-related transcription factor Fli-1 affects many developmental programs including erythroid and megakaryocytic differentiation, and is frequently de-regulated in cancer. Fli-1 was initially isolated following retrovirus insertional mutagenesis screens for leukemic initiator genes, and accordingly, inhibition of this transcription factor can suppress leukemia through induction of erythroid differentiation. To search for modulators of Fli-1, we hereby performed repurposing drug screens with compounds isolated from Chinese medicinal plants. We identified agents that can transcriptionally activate or inhibit a Fli-1 reporter. Remarkably, agents that increased Fli-1 transcriptional activity conferred a strong anti-cancer activity upon Fli-1-expressing leukemic cells in culture. As opposed to drugs that suppress Fli1 activity and lead to erythroid differentiation, growth suppression by these new Fli-1 transactivating compounds involved erythroid to megakaryocytic conversion (EMC). The identified compounds are structurally related to diterpene family of small molecules, which are known agonists of protein kinase C (PKC). In accordance, these PKC agonists (PKCAs) induced PKC phosphorylation leading to activation of the mitogen-activated protein kinase (MAPK) pathway, increased cell attachment and EMC, whereas pharmacological inhibition of PKC or MAPK diminished the effect of our PKCAs. Moreover, in a mouse model of leukemia initiated by Fli-1 activation, the PKCA compounds exhibited strong anti-cancer activity, which was accompanied by increased presence of CD41/CD61 positive megakaryocytic cells in leukemic spleens. Thus, PKC agonists offer a novel approach to combat Fli-1-induced leukemia, and possibly other cancers,by inducing EMC in part through over-activation of the PKC-MAPK-Fli-1 pathway.
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.
authors.forename: Tangjingjun
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: College of Ecology, Lishui University, Zhejiang, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Deng
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|The Laboratory of Cell Biochemistry and Topogenic Regulation, College of Bioengineering and Faculty of Sciences, Chongqing University, Chongqing, China.
authors.forename: Jialei
authors.initials: J
authors.lastname: Song
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Han
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|School of Pharmaceutical Sciences, Guizhou University, Guizhou, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Xia
authors.affiliation: Department of Anatomy, Norman Bethune College of Medicine, Jilin University, Changchun, China.
authors.forename: You-Jun
authors.initials: YJ
authors.lastname: Li
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Maksym
authors.initials: M
authors.lastname: Plachynta
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Mu
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Yan
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Mu
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Luo
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Division of Advanced Diagnostics, Toronto General Research Institute-University Health Network, Toronto, Ontario, Canada.
authors.forename: Eldad
authors.initials: E
authors.lastname: Zacksenhaus
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|School of Pharmaceutical Sciences, Guizhou University, Guizhou, China.|State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.
authors.forename: Xiaojiang
authors.initials: X
authors.lastname: Hao
authors.affiliation: Department of Biology and Chemistry, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou, China.|State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, China.
authors.forename: Yaacov
authors.initials: Y
authors.lastname: Ben-David
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D004224:Diterpenes / Q000494:pharmacology*; D015672:Erythroid Precursor Cells / Q000187:drug effects / Q000473:pathology; D006801:Humans; D020014:K562 Cells; D004915:Leukemia, Erythroblastic, Acute / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D020935:MAP Kinase Signaling System; D008533:Megakaryocytes / Q000187:drug effects / Q000473:pathology; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism*; D041681:NIH 3T3 Cells; D011493:Protein Kinase C / Q000378:metabolism*; D051789:Proto-Oncogene Protein c-fli-1 / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D054852:Small Molecule Libraries / Q000494:pharmacology*; D015534:Trans-Activators
chemical_list: D004224:Diterpenes; C098179:FLII protein, human; C497426:Fli1 protein, mouse; D008840:Microfilament Proteins; D051789:Proto-Oncogene Protein c-fli-1; D018160:Receptors, Cytoplasmic and Nuclear; D054852:Small Molecule Libraries; D015534:Trans-Activators; D011493:Protein Kinase C
keywords: Fli-1; PKC; drug screens; erythroid and megakaryocytic differentiation; leukemia therapy