title: Celecoxib inhibits MDR1 expression through COX-2-dependent mechanism in human hepatocellular carcinoma (HepG2) cell line.
abstract: The role of COX-2 in the regulation of the expression of MDR1, a P-glycoprotein involved in hepatocellular carcinoma cell line, HepG2, was studied in the present investigation. Celecoxib, a selective inhibitor of COX-2, at 25 microM concentration increased the accumulation of doxorubicin in HepG2 cells and enhanced the sensitivity of the cells to doxorubicin by tenfold. The induction of MDR1 expression by PGE2 and its downregulation by celecoxib or by COX-2 knockdown suggests that the enhanced sensitivity of HepG2 cells to doxorubicin by celecoxib is mediated by the downregulation of MDR1 expression, through COX-2-dependent mechanism. Further studies revealed the involvement of AP-1 in the celecoxib-induced downregulation of MDR1 expression. These experimental studies correlated well with in silico predictions and further suggested the inactivation of the signal transduction pathways involving ERK, JNK and p38. The present study thus demonstrates the usefulness of COX-2 intervention in overcoming the drug resistance in HepG2 cells.
authors.affiliation: Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
authors.forename: Karnati R
authors.initials: KR
authors.lastname: Roy
authors.forename: Gorla V
authors.initials: GV
authors.lastname: Reddy
authors.forename: Leela
authors.initials: L
authors.lastname: Maitreyi
authors.forename: Smita
authors.initials: S
authors.lastname: Agarwal
authors.forename: Chandrani
authors.initials: C
authors.lastname: Achari
authors.forename: Shireen
authors.initials: S
authors.lastname: Vali
authors.forename: Pallu
authors.initials: P
authors.lastname: Reddanna
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000378:metabolism*; D000068579:Celecoxib; D049109:Cell Proliferation / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D004317:Doxorubicin / Q000378:metabolism / Q000494:pharmacology; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000201:enzymology / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology*; D013449:Sulfonamides / Q000494:pharmacology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D052246:Cyclooxygenase 2 Inhibitors; D011720:Pyrazoles; D013449:Sulfonamides; D004317:Doxorubicin; D051546:Cyclooxygenase 2; D000068579:Celecoxib