Icariin potentiates the antitumor activity of gemcitabine in gallbladder cancer by suppressing NF-κB
Abstract
Dian-cai ZHANG, Jin-long LIU, Yong-bin DING, Jian-guo XIA*, Guo-yu CHEN*
Department of General Surgery, The First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
Aim: Gemcitabine has been increasingly prescribed for the treatment of gallbladder cancer. However, the response rate is low. The aim of this study is to determine whether icariin, a flavonoid isolated from Epimedi herba, could potentiate the antitumor activity of gemcitabine in gallbladder cancer.
Methods: Human gallbladder carcinoma cell lines GBC-SD and SGC-996 were tested. Cell proliferation and apoptosis were analyzed using MTT assay and flow cytometry, respectively. The expression of apoptosis- and proliferation-related molecules was detected with Western blotting. Caspase-3 activity was analyzed using colorimetric assay, and NF-κB activity was measured with ELISA. A gallbladder cancer xenograft model was established in female BALB/c (nu/nu) mice. The mice were intraperitoneally administered gemcitabine (125 mg/kg) in combination with icariin (40 mg/kg) for 2 weeks.
Results: Icariin (40–160 µg/mL) dose-dependently suppressed cell proliferation and induced apoptosis in both GBC-SD and SGC-996 cells, with SGC-996 cells being less sensitive to the drug. Icariin (40 µg/mL) significantly enhanced the antitumor activity of gemcitabine (0.5 µmol/L) in both GBC-SD and SGC-996 cells. The mice bearing gallbladder cancer xenograft treated with gemcitabine in combination with icariin exhibited significantly smaller tumor size than the mice treated with either drug alone. In GBC-SD cells, icariin significantly inhibited both the constitutive and gemcitabine-induced NF-κB activity, enhanced caspase-3 activity, induced G0-G1 phase arrest, and suppressed the expression of Bcl-2, Bcl-xL and surviving proteins.
Conclusion: Icariin, by suppressing NF-κB activity, exerts antitumor activity, and potentiates the antitumor activity of gemcitabine in gallbladder cancer. Combined administration of gemcitabine and icariin may offer a better therapeutic option for the patients with gallbladder cancer.
Keywords: gallbladder cancer; GBC-SD cell; SGC-996 cell; cancer xenograft model; icariin; gemcitabine; NF-κB; cell cycle arrest; apoptosis; synergistic effect
This work was supported by grants from National Natural Science Foundation of China ( No 30901443) and from the Opening Project of Medical Key Disciplines in Jiangsu Province (No XK03 200904).
* To whom correspondence should be addressed.
E-mail drjianguox@gmail.com (Jian-guo XIA); aroony@gmail.com (Guo-yu CHEN)
Received 2012-08-10 Accepted 2012-10-22
Keywords:
Department of General Surgery, The First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
Aim: Gemcitabine has been increasingly prescribed for the treatment of gallbladder cancer. However, the response rate is low. The aim of this study is to determine whether icariin, a flavonoid isolated from Epimedi herba, could potentiate the antitumor activity of gemcitabine in gallbladder cancer.
Methods: Human gallbladder carcinoma cell lines GBC-SD and SGC-996 were tested. Cell proliferation and apoptosis were analyzed using MTT assay and flow cytometry, respectively. The expression of apoptosis- and proliferation-related molecules was detected with Western blotting. Caspase-3 activity was analyzed using colorimetric assay, and NF-κB activity was measured with ELISA. A gallbladder cancer xenograft model was established in female BALB/c (nu/nu) mice. The mice were intraperitoneally administered gemcitabine (125 mg/kg) in combination with icariin (40 mg/kg) for 2 weeks.
Results: Icariin (40–160 µg/mL) dose-dependently suppressed cell proliferation and induced apoptosis in both GBC-SD and SGC-996 cells, with SGC-996 cells being less sensitive to the drug. Icariin (40 µg/mL) significantly enhanced the antitumor activity of gemcitabine (0.5 µmol/L) in both GBC-SD and SGC-996 cells. The mice bearing gallbladder cancer xenograft treated with gemcitabine in combination with icariin exhibited significantly smaller tumor size than the mice treated with either drug alone. In GBC-SD cells, icariin significantly inhibited both the constitutive and gemcitabine-induced NF-κB activity, enhanced caspase-3 activity, induced G0-G1 phase arrest, and suppressed the expression of Bcl-2, Bcl-xL and surviving proteins.
Conclusion: Icariin, by suppressing NF-κB activity, exerts antitumor activity, and potentiates the antitumor activity of gemcitabine in gallbladder cancer. Combined administration of gemcitabine and icariin may offer a better therapeutic option for the patients with gallbladder cancer.
Keywords: gallbladder cancer; GBC-SD cell; SGC-996 cell; cancer xenograft model; icariin; gemcitabine; NF-κB; cell cycle arrest; apoptosis; synergistic effect
This work was supported by grants from National Natural Science Foundation of China ( No 30901443) and from the Opening Project of Medical Key Disciplines in Jiangsu Province (No XK03 200904).
* To whom correspondence should be addressed.
E-mail drjianguox@gmail.com (Jian-guo XIA); aroony@gmail.com (Guo-yu CHEN)
Received 2012-08-10 Accepted 2012-10-22