title: Increased expression of multidrug resistance-associated proteins in bladder cancer during clinical course and drug resistance to doxorubicin.
abstract: Overexpression of the P-glycoprotein/multidrug resistance 1 (MDR1) and multidrug resistance protein 1 (MRP1) gene is closely associated with the clinical outcome of various malignancies, and it is involved in responses to some anticancer chemotherapeutic agents including doxorubicin. Six human MRP subfamily members (MRP2-7) with structural similarities to MRP1 have been identified. Recently, the relationships between MRP2 and MRP3 expression levels of some cancer cells and drug sensitivity to doxorubicin have been reported, but the relationship between the clinical samples and drug sensitivity remains unclear. We determined the expressions of the MDR1, MRP1, MRP2 and MRP3 gene in bladder cancer during the clinical course and sought to learn whether the expression was correlated with drug responses to doxorubicin. Doxorubicin, used in chemotherapeutic treatment including intravesical and systemic chemotherapy, is an important anticancer agent for the treatment of bladder cancer. We used quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis for our study, and the sensitivity to doxorubicin in bladder cancer was determined using the in vitro succinate dehydrogenase inhibition test. Using 47 clinical samples of bladder cancer, we confirmed the significant correlation of MDR1, MRP1 and MRP3 mRNA levels with resistance to doxorubicin. We showed that the expression of MDR1, MRP1, MRP2 and MRP3 in recurrent tumors and residual tumors after chemotherapeutic treatment was higher than that in untreated primary tumors. In particular, the MDR1 expression in residual tumors was 5.7-fold higher than that in untreated primary tumors.
authors.affiliation: Department of Medical Biochemistry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tada
authors.forename: Morimasa
authors.initials: M
authors.lastname: Wada
authors.forename: Toshiro
authors.initials: T
authors.lastname: Migita
authors.forename: Jun
authors.initials: J
authors.lastname: Nagayama
authors.forename: Eiji
authors.initials: E
authors.lastname: Hinoshita
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Mochida
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Maehara
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tsuneyoshi
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kuwano
authors.forename: Seiji
authors.initials: S
authors.lastname: Naito
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004317:Doxorubicin / Q000494:pharmacology* / Q000627:therapeutic use; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics*; D015999:Multivariate Analysis; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D004317:Doxorubicin; D026901:Membrane Transport Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger; C000715087:ABCC2 protein, human; C114462:multidrug resistance-associated protein 3; C421109:multidrug resistance-associated protein 1