title: Molecular inhibition of prostaglandin E2 with GW627368X: Therapeutic potential and preclinical safety assessment in mouse sarcoma model.
abstract: Prostaglandin E2, the major COX-2 product, acts via 4 functionally distinct prostanoid receptors, EP(1-4). PGE-2, through its receptors, feeds back to positively increase COX-2 expression augmenting its own synthesis thereby driving angiogenesis, while suppressing apoptosis and innate immunity. In addition to the well characterized PGE2/EP4/cAMP/PKA/CREB, EP4 activation increases GSK3 phosphorylation via PI3K and Akt consequently reducing β-catenin phosphorylation. EP4 induces angiogenesis by enhancing VEGF production via ERK activation. These effects of EP4 are asserted either directly or via EGFR transactivation depending on the type of cancer. In view of the safety concerns regarding long term use of COX-2 inhibitors and to find more effective alternatives, we evaluated the potential of EP4 prostanoid receptor as a target for treating cancer progression using a highly selective EP4 antagonist, 4-(4,9-diethoxy-1,3-dihydro-1-oxo-2H-benz[f]isoindol-2-yl)-N-(phenylsulfonyl)-benzeneacetamide. Oral administration of GW627368X showed significant tumor regression characterized by tumor reduction and induction of apoptosis. Reduction in prostaglandin E2 synthesis also led to reduced level of VEGF in plasma. Regulation of multiple pathways downstream of EP4 was evident by down regulation of COX-2, p-Akt, p-MAPK and p-EGFR. Considering wide distribution of the EP4 prostanoid receptor in major organs and the array of physiological processes it contributes to, the safety profile of the drug was analyzed. No major organ toxicity, immunosupression, behavioral change or change in blood parameters attributable to the drug was observed. The results assert the significance of EP4 prostanoid receptor as a therapeutic target as well as the safety of EP4 blockade by GW627368X.
authors.affiliation: a School of Medical Science and Technology; Indian Institute of Technology ; Kharagpur , West Bengal , India.
authors.forename: Sheetal
authors.initials: S
authors.lastname: Parida
authors.forename: Aditya
authors.initials: A
authors.lastname: Parekh
authors.forename: Goutam
authors.initials: G
authors.lastname: Dey
authors.forename: Sukhen C
authors.initials: SC
authors.lastname: Ghosh
authors.forename: Mahitosh
authors.initials: M
authors.lastname: Mandal
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism; D015232:Dinoprostone / Q000037:antagonists & inhibitors*; D004195:Disease Models, Animal; D006801:Humans; D054833:Isoindoles / Q000008:administration & dosage / Q000494:pharmacology*; D020935:MAP Kinase Signaling System; D051379:Mice; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D058309:Receptors, Prostaglandin E, EP4 Subtype / Q000378:metabolism; D012509:Sarcoma / Q000097:blood / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D013449:Sulfonamides / Q000008:administration & dosage / Q000494:pharmacology*; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D054833:Isoindoles; C515270:N-(2-(4-(4,9-diethoxy-1-oxo-1,3-dihydro-2H-benzo(f)isoindol-2-yl)phenyl)acetyl)benzene sulphonamide; D058309:Receptors, Prostaglandin E, EP4 Subtype; D013449:Sulfonamides; D051546:Cyclooxygenase 2; D051057:Proto-Oncogene Proteins c-akt; D015232:Dinoprostone
keywords: AC, Adenylyl cyclase; AIF, Apoptosis inducing factor; ALP, Serum alkaline phosphatase; BUN, Blood urea nitrogen; cAMP, Cyclic adenosine monophosphate; COX, Cyclooxygenase; CREB, cAMP response element-binding protein; EDTA, Ethylenediaminetetraacetic acid;; COX-2; GW627368X; VEGF; prostaglandins; prostanoid receptors