title: The interaction of celecoxib with MDR transporters enhances the activity of mitomycin C in a bladder cancer cell line.
abstract: BACKGROUND
  An in vitro model was developed to understand if celecoxib could synergize with Mitomycin C (MMC), commonly used for the prevention of non-muscle invasive bladder cancer recurrence, and eventually elucidate if the mechanism of interaction involves multi drug resistance (MDR) transporters.
  
  
  METHODS
  UMUC-3, a non COX-2 expressing bladder cancer cell line, and UMUC-3-CX, a COX-2 overexpressing transfectant, as well as 5637, a COX-2 overexpressing cell line, and 5637si-CX, a non COX-2 expressing silenced 5637 cell line, were used in the present study. The expression of COX-2 and MDR pumps (P-gp, MDR-1 and BCRP) was explored through western blot. The anti-proliferative effect of celecoxib and MMC was studied with MTT test. Three biological permeability assays (Drug Transport Experiment, Substrate Transporter Inhibition, and ATP cell depletion) were combined to study the interaction between MDR transporters and celecoxib. Finally, the ability of celecoxib to restore MMC cell accumulation was investigated.
  
  
  RESULTS
  The anti-proliferative effect of celecoxib and MMC were investigated alone and in co-administration, in UMUC-3, UMUC-3-CX, 5637 and 5637si-CX cells. When administered alone, the effect of MMC was 8-fold greater in UMUC-3. However, co-administration of 1 μM, 5 μM, and 10 μM celecoxib and MMC caused a 2,3-fold cytotoxicity increase in UMUC-3-CX cell only. MMC cytotoxicity was not affected by celecoxib co-administration either in 5637, or in 5637si-CX cells. As a result of all finding from the permeability experiments, celecoxib was classified as P-gp unambiguous substrate: celecoxib is transported by MDR pumps and interferes with the efflux of MMC. Importantly, among all transporters, BCRP was only overexpressed in UMUC-3-CX cells, but not in 5637 and 5637si-CX.
  
  
  CONCLUSIONS
  The UMUC-3-CX cell line resembles a more aggressive phenotype with a lower response to MMC compared to the wt counterpart. However, the administration of celecoxib in combination to MMC causes a significant and dose dependent gain of the anti-proliferative activity. This finding may be the result of a direct interaction between celecoxib and MDR transporters. Indeed, BCRP is overexpressed in UMUC-3-CX, but not in UMUC-3, 5637, and 5637si-CX, in which celecoxib is ineffective.
authors.affiliation: Sezione di Urologia e Andrologia, Dipartimento dell'Emergenza e dei Trapianti di Organi (DETO), Università Aldo Moro di Bari, Bari 70124, Italy. vincenzo.pagliarulo@uniba.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Pagliarulo
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ancona
authors.forename: Mauro
authors.initials: M
authors.lastname: Niso
authors.forename: Nicola Antonio
authors.initials: NA
authors.lastname: Colabufo
authors.forename: Marialessandra
authors.initials: M
authors.lastname: Contino
authors.forename: Luigi
authors.initials: L
authors.lastname: Cormio
authors.forename: Amalia
authors.initials: A
authors.lastname: Azzariti
authors.forename: Arcangelo
authors.initials: A
authors.lastname: Pagliarulo
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D001692:Biological Transport; D000068579:Celecoxib; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D018432:Drug Resistance, Multiple; D015870:Gene Expression; D006801:Humans; D016685:Mitomycin / Q000494:pharmacology*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011720:Pyrazoles / Q000378:metabolism*; D013449:Sulfonamides / Q000378:metabolism*; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000903:Antibiotics, Antineoplastic; D000068579:Celecoxib; D051546:Cyclooxygenase 2; D016685:Mitomycin; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D011720:Pyrazoles; D013449:Sulfonamides; C116614:ABCG2 protein, human; C421109:multidrug resistance-associated protein 1