title: Synergistic effects of 8-chlorocyclic-AMP and retinoic acid on induction of apoptosis in Ewing's sarcoma CHP-100 cells.
abstract: The enhanced expression of the regulatory subunit of cyclic AMP (cAMP)-dependent protein kinase type I, RIalpha, has been correlated with cancer cell growth. Retinoic acid (RA) has been shown to play an important role in the regulation of proliferation and differentiation in neoplastic cells. In the present study, the effects of cAMP analogue 8-chlorocyclic-AMP (8-Cl-cAMP) and RA (both singly and combined) on growth inhibition and apoptosis in Ewing's sarcoma CHP-100 cells were evaluated. The inhibitory effects of 8-Cl-cAMP and RA (9-cis-RA, 13-cis-RA, and all-trans-RA) on cell viability were time and dose related. The degree of growth inhibition induced by 9-cis-RA was the greatest among all of the RA analogues (13-cis-RA and all-trans-RA) examined. The combined effects of 8-Cl-cAMP and RA on the induction of growth arrest at the G0-G1 stage of the cell cycle, apoptosis, down-regulation of RIalpha, and cleavage of poly(ADP-ribose) polymerase were synergistic. In conclusion, it is clear that RA and 8-Cl-cAMP act in a synergistic fashion and have potential for combination chemotherapy for the treatment of malignant disease.
authors.affiliation: Cellular Biochemistry Section, Laboratory of Tumor Immunology and Biology, National Cancer Institute, Bethesda, Maryland 20892, USA.
authors.forename: R K
authors.initials: RK
authors.lastname: Srivastava
authors.forename: A R
authors.initials: AR
authors.lastname: Srivastava
authors.forename: Y S
authors.initials: YS
authors.lastname: Cho-Chung
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000031:analogs & derivatives* / Q000633:toxicity; D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D001859:Bone Neoplasms; D002453:Cell Cycle / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009707:Nucleosomes / Q000187:drug effects / Q000473:pathology; D012512:Sarcoma, Ewing; D014212:Tretinoin / Q000633:toxicity*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D009707:Nucleosomes; D015124:8-Bromo Cyclic Adenosine Monophosphate; D014212:Tretinoin; C044258:8-chloro-cyclic adenosine monophosphate