Reversion effects of curcumin on multidrug resistance of MNNG/HOS human osteosarcoma cells in vitro and in vivo through regulation of P-glycoprotein.
BACKGROUND
P-glycoprotein (P-gp) encoded by ATP-binding cassette sub-family B member 1 (ABCB1) gene is a kind of ATP-dependent drug transporter, which plays important roles in multidrug resistance (MDR) of human cancers, such as osteosarcoma. Curcumin is a natural phenolic coloring compound originating from the rhizomes of Curcuma longa, which is proved to possess antitumor biological activities including reversion of MDR. However, the effect and molecular mechanisms of curcumin to osteosarcoma MDR remain unclear.


METHODS
We established a human osteosarcoma drug-resistant cell line MNNG/HOS/MTX by pulse exposure to methotrexate (MTX) and verified that the new cell lines were cross-resistant to other anticancer agents. Then, according to the cytotoxicity assay, we reversed MDR of MNNG/HOS/MTX by 30 µmol/L curcumin, and detected the mechanisms of curcumin reversing MDR through Real-time PCR, Western blotting assay, and Rhodamine123 (Rh123) transport test. Finally, we evaluated the effect of curcumin reversing MDR in vivo by MNNG/HOS/MTX cells xenograft-nude mice model.


RESULTS
MNNG/HOS/MTX was proved to be a human osteosarcoma MDR cell line. MTT tumor chemosensitivity test indicates that 30 µmol/L curcumin attenuates the half maximal inhibitory concentration (IC50) and resistance index (RI) to MTX, diamminedichloroplatinum (DDP), adriamycin (ADM), ifosfamide (IFO), and epirubicin (EPI) in MNNG/HOS/MTX cells (P < 0.05). Real-time PCR and Western blotting assays demonstrated that curcumin down-regulated P-gp expression of MNNG/HOS/MTX cells. Rh123 transport test showed that curcumin inhibited the transport function of P-gp in vitro. In vivo studies showed that curcumin displayed the features of sensitizing antitumor drugs and inhibiting the proliferation, invasion, and metastasis of osteosarcoma MDR cells.


CONCLUSIONS
Down-regulation of P-gp and inhibition of the function of P-gp efflux pump may contribute to MDR reversion induced by curcumin in vitro and in vivo.
Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China.
Meng
M
Si
Jie
J
Zhao
Xin
X
Li
Ji-Guang
JG
Tian
Yong-Gang
YG
Li
Jian-Min
JM
Li
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D045744:Cell Line, Tumor; D003474:Curcumin; D018432:Drug Resistance, Multiple / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D012516:Osteosarcoma / Q000188:drug therapy* / Q000235:genetics
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D003474:Curcumin; D008727:Methotrexate