Preventing chemoresistance of human breast cancer cell line, MCF-7 with celecoxib.
OBJECTIVE
To investigate the preventive effect of celecoxib, a specific cyclooxygenase-2 (Cox-2) inhibitor, on the development of chemoresistance in breast cancer cell line, MCF-7, and explore the mechanism of the action.


METHODS
Chemoresistance phenotype was established by treating MCF-7 cells with 0.05 μg/ml doxorubicin for 7 days, and then the effect of preventive chemoresistance was investigated by the combination of same dose of doxorubicin with 10 μM celecoxib. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay was used to assess cytostatic efficacy of doxorubicin and 50% inhibiting concentration (IC(50)) of MCF-7 cells. RT-PCR was performed to examine mRNA expression of multidrug resistance gene 1 (MDR1) and its transcription factors c-Jun and NF-κB. Western blotting analysis was performed to detect the expression of protein. Flow cytometry (FCM) was applied to analyze the expression and function of P-glycoprotein (P-gp). Electrophoretic gel mobility shift assay (EMSA) was performed to determine the DNA-binding activity of nuclear transcription factors AP-1 and NF-κB.


RESULTS
Compared with sensitive MCF-7 cells, MDR1 and its transcription factors c-Jun and NF-κB were up-regulated at both mRNA level (P < 0.01) and protein level (P < 0.01) by treatment with 0.05 μg/ml doxorubicin for 7 days. After co-incubation with both the same dose of doxorubicin and 10 μM celecoxib for 7 days, both mRNA level and protein level of MDR1, c-Jun and NF-κB up-regulated by doxorubicin were partly reversed (P < 0.01); DNA-binding activity of nuclear transcription factors AP-1 and NF-κB were inhibited; and the function of P-gp was decreased (P < 0.01). When MCF-7 cells were treated with increasing doses of doxorubicin in the presence of 10 μM celecoxib, IC50 value of doxorubicin and doxorubicin plus 10 μM celecoxib was 0.67 ± 0.03 and 0.38 ± 0.04 μg/ml, respectively (P < 0.01).


CONCLUSIONS
Celecoxib effectively prevents the development of chemoresistance in breast cancer cell line MCF-7 induced by doxorubicin, which was partly involved in inhibiting the expression and DNA-binding activity of nuclear transcription factors AP-1 and NF-κB and downstream expression and function of P-gp. Furthermore, cytostatic efficacy of celecoxib and doxorubicin on MCF-7 cell was synergistic.
Chen
Chen
C
The Affiliated People's Hospital, Jiangsu University, Zhenjiang, People's Republic of China.
Shen
Hui Ling
HL
Yang
Jing
J
Chen
Qiao Yun
QY
Xu
Wen Lin
WL
D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics; D000068579:Celecoxib; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000235:genetics / Q000502:physiology*; D005260:Female; D006801:Humans; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism
C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D052246:Cyclooxygenase 2 Inhibitors; D016328:NF-kappa B; D011720:Pyrazoles; D012333:RNA, Messenger; D013449:Sulfonamides; D018808:Transcription Factor AP-1; D004317:Doxorubicin; D000068579:Celecoxib