title: Increase of Intracellular Cyclic AMP by PDE4 Inhibitors Affects HepG2 Cell Cycle Progression and Survival.
abstract: Type 4 cyclic nucleotide phosphodiesterases (PDE4) are major members of a superfamily of enzymes (PDE) involved in modulation of intracellular signaling mediated by cAMP. Broadly expressed in most human tissues and present in large amounts in the liver, PDEs have in the last decade been key therapeutic targets for several inflammatory diseases. Recently, a significant body of work has underscored their involvement in different kinds of cancer, but with no attention paid to liver cancer. The present study investigated the effects of two PDE4 inhibitors, rolipram and DC-TA-46, on the growth of human hepatoma HepG2 cells. Treatment with these inhibitors caused a marked increase of intracellular cAMP level and a dose- and time-dependent effect on cell growth. The concentrations of inhibitors that halved cell proliferation to about 50% were used for cell cycle experiments. Rolipram (10 μM) and DC-TA-46 (0.5 μM) produced a decrease of cyclin expression, in particular of cyclin A, as well as an increase in p21, p27 and p53, as evaluated by Western blot analysis. Changes in the intracellular localization of cyclin D1 were also observed after treatments. In addition, both inhibitors caused apoptosis, as demonstrated by an Annexin-V cytofluorimetric assay and analysis of caspase-3/7 activity. Results demonstrated that treatment with PDE4 inhibitors affected HepG2 cell cycle and survival, suggesting that they might be useful as potential adjuvant, chemotherapeutic or chemopreventive agents in hepatocellular carcinoma. J. Cell. Biochem. 118: 1401-1411, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Massimi
authors.affiliation: Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Cardarelli
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Galli
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Maria Federica
authors.initials: MF
authors.lastname: Giardi
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Ragusa
authors.affiliation: Liver Research Unit, Bambino Gesù Children's Hospital and IRCC, Rome, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Panera
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Cinque
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Cifone
authors.affiliation: Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Biagioni
authors.affiliation: Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Giorgi
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D058988:Phosphodiesterase 4 Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D011621:Pteridines / Q000494:pharmacology; D020889:Rolipram / Q000494:pharmacology
chemical_list: D018797:Cell Cycle Proteins; D058988:Phosphodiesterase 4 Inhibitors; D010879:Piperazines; D011621:Pteridines; C081896:7-benzylamino-6-chloro-2-piperazino-4-pyrrolidinopteridine; D000242:Cyclic AMP; D020889:Rolipram
keywords: APOPTOSIS; CYCLIC NUCLEOTIDE PHOSPHODIESTERASE; CYCLINS; DC-TA-46; HUMAN HEPATOCARCINOMA CELLS; HepaRG; LIVER; ROLIPRAM