Silvestrol

Silvestrol inhibited protein synthesis in MDA-MB-231 breast and PC-3 prostate cancer cell lines with IC50 ~60 nM following a 1 h exposure) [1]. Silvestrol inhibited cell growth with an IC50 of 12.5-86 nM in four different HCC cell lines [3].
Silvestrol, a member of flavagline family of natural products from the genus of Aglaia exhibiting anti-cancer activity in vitro and in vivo and inhibiting translation initiation, was shown to be capable of modulating chemosensitivity in a mechanism-based mouse model.
Preclinical study: A previous study demonstrated that silvestrol showed antileukemia activity at nanomolar concentrations in both 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)]. Moreover, silvestrol was observed to efficiently inhibite FLT3 translation resulting in a decrese of FLT3 protein expression by 80–90%. Animal study indicated that the median survival of silvestrol-treated mice significantly increased (silvestrol-treated vs vehicle-treated = 63 vs 29 days postengraftment) [2]. Another study showed that silvestrol could increase the activities of apoptosis and caspase 3/7. In vivo, the antitumor effect was found with 0.4 mg/kg silvestrol, and the survival of tumor-bearing mice was improved with a median survival time of 42 and 28 days in the silvestrol and control groups, respectively [3].
Clinical study: Currently, there is no clinical data about the anti-cancer efficacy of silvestrol. A grant application proposeed to pursue a Phase I clinical trial to assess the safety, maximum tolerated dose, pharmacokinetic and pharmacodynamic properties, and preliminary efficacy of silvestrol in patients with relapsed, refractory Chronic lymphocytic leukemia (Pre-Clinical and Clinical Development of Silvestrol in Chronic Lymphocytic).
References:
[1] Cencic R, Carrier M, Galicia-Vázquez G, Bordeleau ME, Sukarieh R, Bourdeau A, Brem B, Teodoro JG, Greger H, Tremblay ML, Porco JA Jr, Pelletier J Antitumor activity and mechanism of action of the cyclopenta[b]benzofuran, silvestrol. PLoS One. 2009;4(4):e5223. doi: 10.1371/journal.pone.0005223.
[2] Alachkar H, Santhanam R, Harb JG, Lucas DM, Oaks JJ, Hickey CJ, Pan L, Kinghorn AD, Caligiuri MA, Perrotti D, Byrd JC, Garzon R, Grever MR, Marcucci G. Silvestrol exhibits significant in vivo and in vitro antileukemic activities and inhibits FLT3 and miR-155 expressions in acute myeloid leukemia. J Hematol Oncol. 2013;6:21. doi: 10.1186/1756-8722-6-21.
[3] Kogure T, Kinghorn AD, Yan I, Bolon B, Lucas DM, Grever MR, Patel T. Therapeutic potential of the translation inhibitor silvestrol in hepatocellular cancer. PLoS One. 2013;8(9):e76136. doi: 10.1371/journal.pone.0076136.