Pro-Apoptotic Activity of Artichoke Leaf Extracts in Human HT-29 and RKO Colon Cancer Cells.

(1) Background: Cynara cardunculus L. subsp. scolymus (L.) Hegi, popularly known as artichoke, is an herbaceous plant belonging to the Asteraceae family. Artichoke leaf extracts (ALEs) have been widely used in traditional medicine because of their hepatoprotective, cholagogic, hypoglycaemic, hypolipemic and antibacterial properties. ALEs are also recognized for their antioxidative and anti-inflammatory activities. In this study, we evaluated the cytotoxic, genotoxic, and apoptotic activities, as well as effect on cell growth of ALEs on human colon cancer HT-29 and RKO cells. HT-29 and RKO cells exhibit a different p53 status: RKO cells express the wild-type protein, whereas HT-29 cells express a p53-R273H contact mutant. (2) Methods: Four different ALEs were obtained by sequential extraction of dried artichoke leaves; ALEs were characterized for their content in chlorogenic acid, cynaropicrin, and caffeoylquinic acids. HT-29 and RKO cells were used for in vitro testing (i.e., cytotoxicity and genotoxicity assessment, cell cycle analysis, apoptosis induction). (3) Results: Two out of the four tested ALEs showed marked effects on cell vitality toward HT-29 and RKO tumour cells. The effect was accompanied by a genotoxic activity exerted at a non-cytotoxic concentrations, by a significant perturbation of cell cycle (i.e., with increase of cells in the sub-G1 phase), and by the induction of apoptosis. (4) Conclusions: ALEs rich in cynaropicrin, caffeoylquinic acids, and chlorogenic acid showed to be capable of affecting HT-29 and RKO colon cancer cells by inducing favourable biological effects: cell cycle perturbation, activation of mitochondrial dependent pathway of apoptosis, and the induction of genotoxic effects probably mediated by the induction of apoptosis. Taken together, these results weigh in favour of a potential cancer chemotherapeutic activity of ALEs.

Sulforaphane and Epigallocatechin Gallate Restore Estrogen Receptor Expression by Modulating Epigenetic Events in the Breast Cancer Cell Line MDA-MB-231: A Systematic Review and Meta-Analysis.

BACKGROUND/AIMS: Epigenetics refers to modifications in gene activity and expression without alteration at the DNA sequence. Environment and diet could influence gene expression. Diet modifications may be meaningful in preventing and treating chronic diseases, cancer included. Dietary bioactive compounds, such as polyphenols (e.g., curcumin, resveratrol, or epigallocatechin gallate [EGCG]) or isothiocyanate (e.g., sulforaphane [SFN]), can regulate histone acetylation. The aim of this systematic review and meta-analysis was to evaluate the effect of SFN and EGCG on breast cancer (BC) cells cultured in vitro. METHODS: Due to the enormous variability observed in study protocols and the innumerable genes involved, only studies analyzing the number of apoptotic cells in the MDA-MB-231 cell line were evaluated. The effect size (ES) was computed as the ratio of means. RESULTS: We identified 7 studies, 4 regarding the effect of 10 µM SFN on MDA-MB-231 cells (ES = 4.59, 95% confidence interval 4.05-5.20) and 3 focusing on the impact of 20 µM EGCG (ES = 2.84, 95% confidence interval 2.60-3.10). CONCLUSION: The findings suggest beneficial effects of dietary bioactive compounds such as SFN and EGCG and their effect on BC cells by restoring estrogen receptor gene expression, modulating epigenetic changes and events, and interfering with tumor growth rate. Publication bias limits the generalizability of the conclusions. High-quality studies are needed.

Acid sphingomyelinase as target of Lycium Chinense: promising new action for cell health.

BACKGROUND: Sphingomyelin plays very important roles in cell function under physiological and pathological conditions. Physical and chemical stimuli produce reactive oxygen species that stimulate acid sphingomyelinase to induce apoptosis. Antioxidant plants of the traditional Chinese Pharmacopoeia, such as Lycium Barbarum and Lycium Chinense, have become increasingly popular in Western countries. We investigated the effects of Lycium Chinense on acid sphingomyelinase and sphingomyelin species in relation to gene expression. METHODS: We prepared Lycium Chinense berry extracts and evaluated their antioxidant properties. Increasing amount of extracts was used to test cytotoxic and genotoxic effect on HepG2 cells. Gene expression, protein amount and enzyme activity of acid sphingomyelinase were tested by RT-PCR, immunoblotting and enzymatic activity assay, respectively. Sphingomyelin species were analyzed by UFLC MS/MS. A panel of 96 genes involved in oxidative stress, proliferation, apoptosis and cancer was used to test the effect of LC on gene expression. GLRX2, RNF7, and PTGS1 proteins were analyzed by immunoblotting. RESULTS: We showed that Lycium Chinense berries have high antioxidant properties, have an IC50value of 9.55 mg/mL, do not induce genotoxic effect and maintain high level of cell viability. The berry extracts inhibit acid sphingomyelinase activity and increase both very long fatty acid sphingomyelin species and unsaturated fatty acid sphingomyelin species. Among 96 genes, Lycium Chinense berries up-regulate Glutaredoxin 2 and Ring Finger Protein 7 genes and proteins, able to protect cells from apoptosis. Intrigantly, Lycium Chinense berries down-regulates Prostaglandin H synthase 1 gene but the protein is not expressed in HepG2 cells. CONCLUSION: The results identify acid sphingomyelinase as a novel target of Lycium Chinense berries to decrease saturated/unsaturated fatty acid sphingomyelin ratio, known to be useful for cell health. Consistent with these data, the berries regulate specifically gene expression to protect cells from apoptosis.

In Vitro Safety/Protection Assessment of Resveratrol and Pterostilbene in a Human Hepatoma Cell Line (HepG2).

The aim of this work was to evaluate in vitro the genotoxic and/or antigenotoxic effects of resveratrol (RESV) and pterostilbene (PTER) on HepG2 cells. Moreover, additional tests were performed to evaluate early and late apoptosis events induced by the tested stilbenes. RESV and PTER did not show any genotoxic activity. As regards antigenotoxicity testing, RESV and PTER showed a typical, U-shaped hormetic dose-response relationship characterized by a biphasic trend with small quantities having opposite effects to large ones. HepG2 cells treated with PTER exhibited a marked increase in early apoptosis (40.1%) at 250 microM; whereas, the highest concentration tested for both RESV and PTER significantly increased the proportion of HepG2 cells undergoing late apoptosis (32.5 and 51.2%, respectively). The observed pro-apoptotic activity could, at least in part, explain the hormetic response observed when the compounds were tested for antigenotoxicity (i.e., in the presence of induced DNA damage).