TY - JOUR
T1 - High expression of sphingosine kinase 1 and S1P receptors in chemotherapy-resistant prostate cancer PC3 cells and their camptothecin-induced up-regulation
AU - Akao, Yukihiro
AU - Banno, Yoshiko
AU - Nakagawa, Yoshihito
AU - Hasegawa, Nobuko
AU - Kim, Tack Joong
AU - Murate, Takashi
AU - Igarashi, Yasuyuki
AU - Nozawa, Yoshinori
N1 - Funding Information:
This work was supported in part by Grants-in-Aid for Scientific Research (B) (09480162) and (C) (17510175) from the Ministry of Education, Science, Sports and Culture of Japan.
PY - 2006/4/21
Y1 - 2006/4/21
N2 - Although most of pharmacological therapies for cancer utilize the apoptotic machinery of the cells, the available anti-cancer drugs are limited due to the ability of prostate cancer cells to escape from the anti-cancer drug-induced apoptosis. A human prostate cancer cell line PC3 is resistant to camptothecin (CPT). To elucidate the mechanism of this resistance, we have examined the involvement of sphingosine kinase (SPHK) and sphingosine 1-phosphate (S1P) receptor in CPT-resistant PC3 and -sensitive LNCaP cells. PC3 cells exhibited higher activity accompanied with higher expression levels of protein and mRNA of SPHK1, and also elevated expression of S1P receptors, S1P1 and S1P3, as compared with those of LNCaP cells. The knockdown of SPHK1 by small interfering RNA and inhibition of S1P receptor signaling by pertussis toxin in PC3 cells induced significant inhibition of cell growth, suggesting implication of SPHK1 and S1P receptors in cell proliferation in PC3 cells. Furthermore, the treatment of PC3 cells with CPT was found to induce up-regulation of the SPHK1/S1P signaling by induction of both SPHK1 enzyme and S1P1/S1P3 receptors. These findings strongly suggest that high expression and up-regulation of SPHK1 and S1P receptors protect PC3 cells from the apoptosis induced by CPT.
AB - Although most of pharmacological therapies for cancer utilize the apoptotic machinery of the cells, the available anti-cancer drugs are limited due to the ability of prostate cancer cells to escape from the anti-cancer drug-induced apoptosis. A human prostate cancer cell line PC3 is resistant to camptothecin (CPT). To elucidate the mechanism of this resistance, we have examined the involvement of sphingosine kinase (SPHK) and sphingosine 1-phosphate (S1P) receptor in CPT-resistant PC3 and -sensitive LNCaP cells. PC3 cells exhibited higher activity accompanied with higher expression levels of protein and mRNA of SPHK1, and also elevated expression of S1P receptors, S1P1 and S1P3, as compared with those of LNCaP cells. The knockdown of SPHK1 by small interfering RNA and inhibition of S1P receptor signaling by pertussis toxin in PC3 cells induced significant inhibition of cell growth, suggesting implication of SPHK1 and S1P receptors in cell proliferation in PC3 cells. Furthermore, the treatment of PC3 cells with CPT was found to induce up-regulation of the SPHK1/S1P signaling by induction of both SPHK1 enzyme and S1P1/S1P3 receptors. These findings strongly suggest that high expression and up-regulation of SPHK1 and S1P receptors protect PC3 cells from the apoptosis induced by CPT.
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U2 - 10.1016/j.bbrc.2006.02.070
DO - 10.1016/j.bbrc.2006.02.070
M3 - Article
C2 - 16516161
AN - SCOPUS:33644886904
SN - 0006-291X
VL - 342
SP - 1284
EP - 1290
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -
