title: HDAC inhibition amplifies gap junction communication in neural progenitors: potential for cell-mediated enzyme prodrug therapy.
abstract: Enzyme prodrug therapy using neural progenitor cells (NPCs) as delivery vehicles has been applied in animal models of gliomas and relies on gap junction communication (GJC) between delivery and target cells. This study investigated the effects of histone deacetylase (HDAC) inhibitors on GJC for the purpose of facilitating transfer of therapeutic molecules from recombinant NPCs. We studied a novel immortalized midbrain cell line, NGC-407 of embryonic human origin having neural precursor characteristics, as a potential delivery vehicle. The expression of gap junction protein connexin 43 (Cx43) was analyzed by western blot and immunocytochemistry. While Cx43 levels were decreased in untreated differentiating NGC-407 cells, the HDAC inhibitor 4-phenylbutyrate (4-PB) increased Cx43 expression along with increased membranous deposition in both proliferating and differentiating cells. Simultaneously, Ser 279/282-phosphorylated form of Cx43 was declined in both culture conditions by 4-PB. The 4-PB effect in NGC-407 cells was verified by using HNSC.100 human neural progenitors and Trichostatin A. Improved functional GJC is of imperative importance for therapeutic strategies involving intercellular transport of low molecular-weight compounds. We show here an enhancement by 4-PB, of the functional GJC among NGC-407 cells, as well as between NGC-407 and human glioma cells, as indicated by increased fluorescent dye transfer.
authors.affiliation: Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden. zahidul.khan@ki.se
authors.forename: Zahidul
authors.initials: Z
authors.lastname: Khan
authors.forename: Monira
authors.initials: M
authors.lastname: Akhtar
authors.forename: Thomas
authors.initials: T
authors.lastname: Asklund
authors.forename: Bengt
authors.initials: B
authors.lastname: Juliusson
authors.forename: Per M
authors.initials: PM
authors.lastname: Almqvist
authors.forename: Tomas J
authors.initials: TJ
authors.lastname: Ekström
mesh_terms: D002450:Cell Communication / Q000187:drug effects; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D018031:Connexin 43 / Q000032:analysis / Q000378:metabolism; D016503:Drug Delivery Systems; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D017629:Gap Junctions / Q000737:chemistry / Q000187:drug effects*; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D009474:Neurons / Q000201:enzymology* / Q000637:transplantation*; D010654:Phenylbutyrates / Q000494:pharmacology; D011355:Prodrugs / Q000008:administration & dosage*; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000201:enzymology
chemical_list: D018031:Connexin 43; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D010654:Phenylbutyrates; D011355:Prodrugs; C012589:trichostatin A; C075773:4-phenylbutyric acid