TY - JOUR
T1 - Upregulation of drug transporter expression by osteopontin in prostate cancer cellss
AU - Hsieh, I. Shan
AU - Huang, Wei Hsun
AU - Liou, Houng Chi
AU - Chuang, Woei Jer
AU - Yang, Rong Sen
AU - Fu, Wen Mei
PY - 2013/5
Y1 - 2013/5
N2 - Multidrug resistance is a major cause of chemotherapy failure. Recent studies indicate that drug resistance can be rapidly induced by some soluble factors, such as cytokines, chemokines, growth factors, and cell adhesion factors in the tumor microenvironment. Osteopontin (OPN), an extracellular matrix protein, has a functional arginine-glycine-aspartic acid (RGD) domain for binding to integrin. Here we found OPN expression to be upregulated by hypoxic condition in PC-3 prostate tumor cells. OPN increased the mRNA and protein expression of pglycoprotein (P-gp), a subfamily of ATP-binding cassette transporter in a concentration- and time-dependent manner. The increase in P-gp transporter by OPN was mediated by binding to avb3 integrin. Daunomycin (DUN), a chemotherapeutic agent with autofluorescence, was used to evaluate the pump activity, and OPN increased the drug pumping-out activity. OPN inhibited DUN-induced cell death, which was antagonized by avb3 monoclonal antibody. Long-term treatment with DUN further enhanced the expression of OPN. Knockdown of endogenous OPN potentiated the DUN-induced apoptosis of PC-3 cells. Furthermore, knockdown of OPN enhanced cell death caused by other drugs, including paclitaxel, doxorubicin, actinomycin- D, and rapamycin, which are also P-gp substrates. The animal studies also showed that OPN knockdown enhanced the cytotoxic action of DUN. These results indicate that OPN is a potential therapeutic target for cancer therapy to reduce drug resistance in sensitive tumors.
AB - Multidrug resistance is a major cause of chemotherapy failure. Recent studies indicate that drug resistance can be rapidly induced by some soluble factors, such as cytokines, chemokines, growth factors, and cell adhesion factors in the tumor microenvironment. Osteopontin (OPN), an extracellular matrix protein, has a functional arginine-glycine-aspartic acid (RGD) domain for binding to integrin. Here we found OPN expression to be upregulated by hypoxic condition in PC-3 prostate tumor cells. OPN increased the mRNA and protein expression of pglycoprotein (P-gp), a subfamily of ATP-binding cassette transporter in a concentration- and time-dependent manner. The increase in P-gp transporter by OPN was mediated by binding to avb3 integrin. Daunomycin (DUN), a chemotherapeutic agent with autofluorescence, was used to evaluate the pump activity, and OPN increased the drug pumping-out activity. OPN inhibited DUN-induced cell death, which was antagonized by avb3 monoclonal antibody. Long-term treatment with DUN further enhanced the expression of OPN. Knockdown of endogenous OPN potentiated the DUN-induced apoptosis of PC-3 cells. Furthermore, knockdown of OPN enhanced cell death caused by other drugs, including paclitaxel, doxorubicin, actinomycin- D, and rapamycin, which are also P-gp substrates. The animal studies also showed that OPN knockdown enhanced the cytotoxic action of DUN. These results indicate that OPN is a potential therapeutic target for cancer therapy to reduce drug resistance in sensitive tumors.
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U2 - 10.1124/mol.112.082339
DO - 10.1124/mol.112.082339
M3 - Article
C2 - 23434829
AN - SCOPUS:84876544010
SN - 0026-895X
VL - 83
SP - 968
EP - 977
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 5
ER -