TY - JOUR
T1 - A novel combination of withaferin A and sorafenib shows synergistic efficacy against both papillary and anaplastic thyroid cancers
AU - Cohen, Stephanie M.
AU - Mukerji, Ridhwi
AU - Timmermann, Barbara N.
AU - Samadi, Abbas K.
AU - Cohen, Mark S.
N1 - Funding Information:
This work was supported in part by funding from the National Institutes of Health Centers of Biomedical Research Excellence ( P20 RR015563 to B.M.T.) as well as the Institute for Advancing Medical Innovation (M.S.C.) and the Department of Surgery at the University of Kansas Medical Center.
PY - 2012/12
Y1 - 2012/12
N2 - Background: Sorafenib (SO), a multikinase-targeted inhibitor in clinical trials for papillary and anaplastic cancers, shows limited efficacy with moderate toxicity. Withaferin A (WA), a natural withanolide, shows potent preclinical anticancer activity in thyroid cancers through multiple cytotoxic mechanisms including heat-shock protein inhibition. We hypothesized that combination therapy (WA + SO) would have a synergistic effect against anaplastic and papillary carcinoma cells at lower sorafenib doses. Methods: Human papillary (BCPAP) and anaplastic (SW1736) thyroid cancer cell lines were evaluated after treatment with SO, WA, or their combination at different doses. Proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium and trypan blue exclusion; apoptosis and cell-cycle arrest was measured by flow cytometry. Western analysis confirmed apoptosis (Poly ADP ribose polymerase [PARP] and caspase-3 cleavage) and Raf inhibition. Experiments were repeated in triplicate and were evaluated statistically with significance set at a P value of less than.05. Results: The concentration of drug at which 50% of the cells are inhibited (IC50) in BCPAP were 6.3 μmol/L (SO),.155 μmol/L (WA), and.055 μmol/L (IC50WA + 50% IC50SO), whereas in SW1736 cells the concentration was 7.6 μmol/L (SO), 2.5 μmol/L (WA), and 1.4 μmol/L (IC50WA + 50% IC50SO). Combination (WA + SO) at IC50 decreased cell viability to 19% (from 50% individually). Apoptosis levels on flow cytometry in anaplastic cells increased significantly from 0% to 2% (SO or WA alone) to 89% (combo at IC50, P <.001). Combination therapy apoptosis (PARP cleavage and caspase-3 inactivation) and BRAF/Raf-1 down-regulation were dose-dependent starting at 50% IC50 levels. Cell-cycle modulation was significant with combination treatment (35% increase in G2 arrest at 50% IC50SO + WA and 70% increase at 75% IC50SO + WA; P <.01). Conclusions: Combination therapy with sorafenib + withaferin showed synergistic efficacy in papillary and anaplastic cancers in vitro with significant induction of apoptosis. This combination achieved potent anticancer activity with lower overall doses of sorafenib, indicating a potential strategy to decrease sorafenib toxicity in future translational studies.
AB - Background: Sorafenib (SO), a multikinase-targeted inhibitor in clinical trials for papillary and anaplastic cancers, shows limited efficacy with moderate toxicity. Withaferin A (WA), a natural withanolide, shows potent preclinical anticancer activity in thyroid cancers through multiple cytotoxic mechanisms including heat-shock protein inhibition. We hypothesized that combination therapy (WA + SO) would have a synergistic effect against anaplastic and papillary carcinoma cells at lower sorafenib doses. Methods: Human papillary (BCPAP) and anaplastic (SW1736) thyroid cancer cell lines were evaluated after treatment with SO, WA, or their combination at different doses. Proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium and trypan blue exclusion; apoptosis and cell-cycle arrest was measured by flow cytometry. Western analysis confirmed apoptosis (Poly ADP ribose polymerase [PARP] and caspase-3 cleavage) and Raf inhibition. Experiments were repeated in triplicate and were evaluated statistically with significance set at a P value of less than.05. Results: The concentration of drug at which 50% of the cells are inhibited (IC50) in BCPAP were 6.3 μmol/L (SO),.155 μmol/L (WA), and.055 μmol/L (IC50WA + 50% IC50SO), whereas in SW1736 cells the concentration was 7.6 μmol/L (SO), 2.5 μmol/L (WA), and 1.4 μmol/L (IC50WA + 50% IC50SO). Combination (WA + SO) at IC50 decreased cell viability to 19% (from 50% individually). Apoptosis levels on flow cytometry in anaplastic cells increased significantly from 0% to 2% (SO or WA alone) to 89% (combo at IC50, P <.001). Combination therapy apoptosis (PARP cleavage and caspase-3 inactivation) and BRAF/Raf-1 down-regulation were dose-dependent starting at 50% IC50 levels. Cell-cycle modulation was significant with combination treatment (35% increase in G2 arrest at 50% IC50SO + WA and 70% increase at 75% IC50SO + WA; P <.01). Conclusions: Combination therapy with sorafenib + withaferin showed synergistic efficacy in papillary and anaplastic cancers in vitro with significant induction of apoptosis. This combination achieved potent anticancer activity with lower overall doses of sorafenib, indicating a potential strategy to decrease sorafenib toxicity in future translational studies.
KW - Anaplastic thyroid cancer
KW - Novel therapy
KW - Papillary thyroid cancer
KW - Sorafenib
KW - Synergistic effects
KW - Withaferin A
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U2 - 10.1016/j.amjsurg.2012.07.027
DO - 10.1016/j.amjsurg.2012.07.027
M3 - Article
C2 - 23231932
AN - SCOPUS:84870975246
SN - 0002-9610
VL - 204
SP - 895
EP - 901
JO - American Journal of Surgery
JF - American Journal of Surgery
IS - 6
ER -