TY - JOUR
T1 - Silvestrol exhibits significant in vivo and in vitro antileukemic activities and inhibits FLT3 and miR-155 expressions in acute myeloid leukemia
AU - Alachkar, Houda
AU - Santhanam, Ramasamy
AU - Harb, Jason G.
AU - Lucas, David M.
AU - Oaks, Joshua J.
AU - Hickey, Christopher J.
AU - Pan, Li
AU - Kinghorn, A. Douglas
AU - Caligiuri, Michael A.
AU - Perrotti, Danilo
AU - Byrd, John C.
AU - Garzon, Ramiro
AU - Grever, Michael R.
AU - Marcucci, Guido
N1 - Funding Information:
This work was supported by the U.S. National Cancer Institute [P01-CA125066 to ADK, SPORE P50-CA140158 to JCB, and The Ohio State University Comprehensive Cancer Center Core Grant].
PY - 2013/12/1
Y1 - 2013/12/1
N2 - Background: Activating mutations [internal tandem duplication (ITD)] or overexpression of the FMS-like tyrosine kinase receptor-3 (FLT3) gene are associated with poor outcome in acute myeloid leukemia (AML) patients, underscoring the need for novel therapeutic approaches. The natural product silvestrol has potent antitumor activity in several malignancies, but its therapeutic impact on distinct molecular high-risk AML subsets remains to be fully investigated. We examined here the preclinical activity of silvestrol in FLT3-ITD and FLT3 wild-type (wt) AML. Methods. Silvestrol in vitro anti-leukemic activity was examined by colorimetric cell viability assay, colony-forming and flow cytometry assays assessing growth inhibition and apoptosis, respectively. Pharmacological activity of silvestrol on FLT3 mRNA translation, mRNA and protein expression was determined by RNA-immunoprecipitation, qRT-PCR and immunoblot analyses, respectively. Silvestrol in vivo efficacy was investigated using MV4-11 leukemia-engrafted mice. Results: Silvestrol shows antileukemia activity at nanomolar concentrations both in FLT3-wt overexpressing (THP-1) and FLT3-ITD (MV4-11) expressing AML cell lines (IC50 = 3.8 and 2.7 nM, respectively) and patients' primary blasts [IC50 = ∼12 nM (FLT3-wt) and ∼5 nM (FLT3-ITD)]. Silvestrol increased apoptosis (∼4fold, P = 0.0001), and inhibited colony-formation (100%, P < 0.0001) in primary blasts. Silvestrol efficiently inhibited FLT3 translation reducing FLT3 protein expression by 80-90% and decreased miR-155 levels (∼60%), a frequently co-regulated onco-miR in FLT3-ITD-positive AML. The median survival of silvestrol-treated vs vehicle-treated mice was 63 vs 29 days post-engraftment, respectively (P < 0.0001). Conclusions: Silvestrol exhibits significant in vivo and in vitro antileukemic activities in AML through a novel mechanism resulting in inhibition of FLT3 and miR-155 expression. These encouraging results warrant a rapid translation of silvestrol for clinical testing in AML.
AB - Background: Activating mutations [internal tandem duplication (ITD)] or overexpression of the FMS-like tyrosine kinase receptor-3 (FLT3) gene are associated with poor outcome in acute myeloid leukemia (AML) patients, underscoring the need for novel therapeutic approaches. The natural product silvestrol has potent antitumor activity in several malignancies, but its therapeutic impact on distinct molecular high-risk AML subsets remains to be fully investigated. We examined here the preclinical activity of silvestrol in FLT3-ITD and FLT3 wild-type (wt) AML. Methods. Silvestrol in vitro anti-leukemic activity was examined by colorimetric cell viability assay, colony-forming and flow cytometry assays assessing growth inhibition and apoptosis, respectively. Pharmacological activity of silvestrol on FLT3 mRNA translation, mRNA and protein expression was determined by RNA-immunoprecipitation, qRT-PCR and immunoblot analyses, respectively. Silvestrol in vivo efficacy was investigated using MV4-11 leukemia-engrafted mice. Results: Silvestrol shows antileukemia activity at nanomolar concentrations both in FLT3-wt overexpressing (THP-1) and FLT3-ITD (MV4-11) expressing AML cell lines (IC50 = 3.8 and 2.7 nM, respectively) and patients' primary blasts [IC50 = ∼12 nM (FLT3-wt) and ∼5 nM (FLT3-ITD)]. Silvestrol increased apoptosis (∼4fold, P = 0.0001), and inhibited colony-formation (100%, P < 0.0001) in primary blasts. Silvestrol efficiently inhibited FLT3 translation reducing FLT3 protein expression by 80-90% and decreased miR-155 levels (∼60%), a frequently co-regulated onco-miR in FLT3-ITD-positive AML. The median survival of silvestrol-treated vs vehicle-treated mice was 63 vs 29 days post-engraftment, respectively (P < 0.0001). Conclusions: Silvestrol exhibits significant in vivo and in vitro antileukemic activities in AML through a novel mechanism resulting in inhibition of FLT3 and miR-155 expression. These encouraging results warrant a rapid translation of silvestrol for clinical testing in AML.
UR - https://www.scopus.com/pages/publications/84874930771
U2 - 10.1186/1756-8722-6-21
DO - 10.1186/1756-8722-6-21
M3 - Article
C2 - 23497456
AN - SCOPUS:84874930771
SN - 1756-8722
VL - 6
JO - Journal of Hematology and Oncology
JF - Journal of Hematology and Oncology
IS - 1
M1 - 21
ER -