Pterostilbene carboxaldehyde thiosemicarbazone, a resveratrol derivative inhibits 17ß-Estradiol induced cell migration and proliferation in HUVECs.

Angiogenesis plays important roles in tumor growth and metastasis, thus development of a novel angiogenesis inhibitor is essential for the improvement of therapeutics against cancer. Thrombospondins-1 (TSP-1) is a potent endogenous inhibitor of angiogenesis that acts through direct effects on endothelial cell migration, proliferation, survival, and activating apoptotic pathways. TSP-1 has been shown to disrupt estrogen-induced endothelial cell proliferation and migration. Here we investigated the potential of pterostilbene carboxaldehyde thiosemicarbazone (PTERC-T), a novel resveratrol (RESV) derivative, to inhibit angiogenesis induced by female sex steroids, particularly 17ß-Estradiol (E2), on Human umbilical vein endothelial cells (HUVECs) and to elucidate the involvement of TSP-1 in PTERC-T action. Our results showed that PTERC-T significantly inhibited 17ß-E2-stimulated proliferation of HUVECs and induced apoptosis as determined by annexin V/propidium iodide staining and cleaved caspase-3 expression. Furthermore, PTERC-T also inhibited endothelial cell migration, and invasion in chick chorioallantoic membrane (CAM) assay. In contrast, RESV failed to inhibit 17ß-E2 induced HUVECs proliferation and invasion at similar dose. PTERC-T was also found to increase TSP-1 protein expression levels in a dose-dependent manner which, however, was counteracted by co-incubation with p38MAPK or JNK inhibitors, suggesting involvement of these pathways in PTERC-T action. These results suggest that the inhibitory effect of PTERC-T on 17ß-E2 induced angiogenesis is associated, at least in part, with its induction of endothelial cell apoptosis and inhibition of cell migration through targeting TSP-1. Thus, PTERC-T could be considered as a potential lead compound for developing a class of new drugs targeting angiogenesis-related diseases.

Role of isothiocyanate conjugate of pterostilbene on the inhibition of MCF-7 cell proliferation and tumor growth in Ehrlich ascitic cell induced tumor bearing mice.

Naturally occurring pterostilbene (PTER) and isothiocyanate (ITC) attract great attention due to their wide range of biological properties, including anti-cancer, anti-leukemic, anti-bacterial and anti-inflammatory activities. A novel class of hybrid compound synthesized by introducing an ITC moiety on PTER backbone was evaluated for its anti-cancer efficacy in hormone-dependent breast cancer cell line (MCF-7) in vitro and Ehrlich ascitic tumor bearing mice model in vivo. The novel hybrid molecule showed significant in vitro anti-cancer activity (IC50=25 ± 0.38) when compared to reference compound PTER (IC50=65 ± 0.42). The conjugate molecule induced both S and G2/M phase cell cycle arrest as indicated by flow cytometry analysis. In addition, the conjugate induced cell death was characterized by changes in cell morphology, DNA fragmentation, activation of caspase-9, release of cytochrome-c into cytosol and increased Bax: Bcl-2 ratio. The conjugate also suppressed the phosphorylation of Akt and ERK. The conjugate induced cell death was significantly increased in presence of A6730 (a potent Akt1/2 kinase inhibitor) and PD98059 (a specific ERK inhibitor). Moreover, the conjugated PTER inhibited tumor growth in Ehrlich ascitic cell induced tumor bearing mice as observed by reduction in tumor volume compared to untreated animals. Collectively, the pro-apoptotic effect of conjugate is mediated through the activation of caspases, and is correlated with the blockade of the Akt and ERK signaling pathways in MCF-7 cells.