Pterostilbene inhibits lung cancer through induction of apoptosis.

BACKGROUND: Lung cancer remains the leading cause of cancer mortality in the United States. Resveratrol is a potent antioxidant found in grapes that inhibits several types of cancer, including lung cancer. Herein, we investigated the effects of pterostilbene, an analog of resveratrol found in blueberries, on lung cancer, in vitro. We hypothesized that pterostilbene would inhibit lung cancer cell growth in vitro by a pro-apoptotic mechanism. METHODS: Two lung cancer cell lines (NCI-H460 and SK-MES-1) were cultured using standard techniques. Cells were treated with increasing doses of pterostilbene (10-100 microM). Cell viability was measured at 24, 48, and 72h using a MTT assay. Apo-ONE Caspase-3/7 assay was used to evaluate caspase activity. T-test and two-way ANOVA were used for statistical analysis. RESULTS: Pterostilbene significantly decreased cell viability in lung cancer cells in a concentration- and time-dependent manner (P<0.001). Concentrations greater than 20 microM of pterostilbene produced significant growth inhibition by 72h (P<0.001). Apoptosis and caspase-3/7 activity were significantly increased by pterostilbene treatment (P<0.05). CONCLUSIONS: Pterostilbene inhibits growth via apoptosis induction in vitro. Further in vitro mechanistic studies and in vivo experiments are warranted to determine the potential role for pterostilbene in lung cancer treatment or prevention.

Pterostilbene inhibits breast cancer in vitro through mitochondrial depolarization and induction of caspase-dependent apoptosis.

BACKGROUND: Epidemiologic studies suggest that diets high in fruits and vegetables reduce cancer risk. Resveratrol, a compound present in grapes, has been shown to inhibit a variety of primary tumors. Pterostilbene, an analogue of resveratrol found in blueberries, has both antioxidant and antiproliferative properties. We hypothesized that pterostilbene would induce apoptosis and inhibit breast cancer cell growth in vitro. METHODS: Breast cancer cells were treated with graduated doses of pterostilbene. Cell viability was measured by MTT assay. Apoptosis was evaluated via DNA fragmentation assay and TUNEL assay. Apo-ONE caspase-3/7 assay was used to evaluate caspase activity. Flow cytometry was used to evaluate mitochondrial depolarization, superoxide formation, and cell cycle. Student's t-test and two-way ANOVA with Bonferroni posttests were utilized for statistical analysis. RESULTS: Pterostilbene decreased breast cancer cell viability in a concentration- and time-dependent manner. Pterostilbene treatment increased caspase-3/7 activity and apoptosis in both cell lines. Caspase-3/7 inhibitors completely reversed pterostilbene's effects on cell viability. Pterostilbene treatment triggered mitochondrial depolarization, increased superoxide anion, and caused alteration in cell cycle. CONCLUSIONS: Pterostilbene treatment inhibits the growth of breast cancer in vitro through caspase-dependent apoptosis. Mitochondrial membrane depolarization and increased superoxide anion may contribute to the activation downstream effector caspases. Caspase inhibition leads to complete reversal of pterostilbene's effect on cell viability. Further in vitro mechanistic studies and in vivo experiments are warranted to determine its potential for the treatment of breast cancer.

Effects of pterostilbene on melanoma alone and in synergy with inositol hexaphosphate.

BACKGROUND: Pterostilbene and inositol-6-phosphate (IP6) have been shown to inhibit melanoma growth in vitro. However, pterostilbene's mechanism of action has not been clearly demonstrated. We aimed to further investigate the mechanism of action for pterostilbene and to determine whether combination treatment with IP6 produced synergistic growth inhibition. METHODS: Melanoma cells were treated with increasing doses of pterostilbene, IP6, or combinations thereof. Cell viability was measured at 24 hours, 48 hours, and 72 hours using a MTT assay. Caspase activity and vascular endothelial growth factor (VEGF) production were measured using enzyme-linked immunosorbent assay (ELISA). Analysis of variance (ANOVA) and t tests were used for statistical analysis. RESULTS: Pterostilbene inhibits melanoma growth in vitro in association with increased effector caspase activity. Combination treatment with inositol hexaphosphate produces synergistic growth inhibition, greater than either treatment alone. CONCLUSIONS: Pterostilbene produces caspase-dependent apoptosis in melanoma cell lines. Combination treatment with IP6 produces synergistic growth inhibition. Both compounds have significant potential for a therapeutic role in the treatment of melanoma.