title: Antagonistic interactions between gemcitabine and 5-fluorouracil in the human pancreatic carcinoma cell line Capan-2.
abstract: Although the recently-developed Gemcitabine (GEM) has renewed interest in clinical research in pancreatic carcinoma, it offers modest improvement of tumor-related symptoms and marginal survival advantage, even when combined with other currently-available chemotherapeutic agents such as 5-Fluorouracil (5-FU). We hypothesized that this disappointing result could be due to an interaction between the two drugs affecting cytotoxic activity. We measured in-vitro growth inhibition, cell cycle distribution, gene and protein expression of apoptosis regulators bcl-2, bcl-x and survivin, NFkappaB and telomerase activities of human pancreatic carcinoma cell line Capan-2 following exposure to GEM and 5-FU singly or combined, by MTT assay and median effect analysis, flow cytometry, real-time RT-PCR, Western blotting, electrophoretic mobility shift assay (EMSA) and telomeric repeat amplification protocol (TRAP) assay, respectively. We found cell growth to be inhibited by both drugs, decreasing the percentage of cells in S and G2/M phases and inducing apoptosis, dependent on the levels of bcl-2, bcl-xL and survivin expression in the case of 5-FU, but not for GEM. Moreover, while telomerase activity was reduced equally by both drugs, 5-FU but not GEM effectively downregulated NFkappaB binding activity. Intriguingly, a substantial antagonistic effect was noticed when GEM was combined with 5-FU in the concentration range tested, with the exception of the TRAP assay. These indications of an antagonistic interaction between GEM and 5-FU in some pancreatic cancer context urge further investigation of both genetic and non-genetic differences to identify the variables most relevant for optimal selection and dosing of treatment for the individual patient.
authors.affiliation: Department of Clinical Physiopathology, University of Turin, and Department of Gastroenterology, San Giovanni Battista Hospital, Turin, Italy. graziella.bellone@unito.it
authors.forename: Graziella
authors.initials: G
authors.lastname: Bellone
authors.forename: Anna
authors.initials: A
authors.lastname: Carbone
authors.forename: Valeria
authors.initials: V
authors.lastname: Busso
authors.forename: Tiziana
authors.initials: T
authors.lastname: Scirelli
authors.forename: Alessandra
authors.initials: A
authors.lastname: Buffolino
authors.forename: Carlo
authors.initials: C
authors.lastname: Smirne
authors.forename: Anna
authors.initials: A
authors.lastname: Novarino
authors.forename: Oscar
authors.initials: O
authors.lastname: Bertetto
authors.forename: Luciano
authors.initials: L
authors.lastname: Tosetti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Emanuelli
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D053143:Caspase 2 / Q000378:metabolism; D061945:Caspase Inhibitors; D002453:Cell Cycle / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D005472:Fluorouracil / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D010190:Pancreatic Neoplasms / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D061945:Caspase Inhibitors; D012333:RNA, Messenger; D003841:Deoxycytidine; D053143:Caspase 2; D005472:Fluorouracil; D000093542:Gemcitabine