Punicalagin induces apoptotic and autophagic cell death in human U87MG glioma cells

• Published in: Acta pharmacologica Sinica Vol. 34; no. 11; pp. 1411 - 1419
• Main Authors: Wang, Shyang-guang, Huang, Ming-hung, Li, Jui-hsiang, Lai, Fu-i, Lee, Horng-mo, Hsu, Yuan-nian
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.11.2013; Nature Publishing Group
• Subjects: AMP-Activated Protein Kinases - metabolism; Antineoplastic Agents, Phytogenic - administration & dosage; Antineoplastic Agents, Phytogenic - isolation & purification; Antineoplastic Agents, Phytogenic - pharmacology; Apoptosis; Apoptosis - drug effects; Autophagy - drug effects; Biomedical and Life Sciences; Biomedicine; Cell Cycle - drug effects; Cell death; Cell Line, Tumor; Cell Survival - drug effects; Dose-Response Relationship, Drug; Flow Cytometry; Glioma - drug therapy; Glioma - pathology; Humans; Hydrolyzable Tannins - administration & dosage; Hydrolyzable Tannins - isolation & purification; Hydrolyzable Tannins - pharmacology; Immunology; Internal Medicine; Medical Microbiology; Original; original-article; Pharmacology/Toxicology; Phosphorylation; Punica granatum; Punicaceae - chemistry; Vaccine; chloroquine; human glioma; autophagy; z-DEVD-fmk; p27; punicalagin; apoptosis; AMPK; microtubule-associated protein light chain 3
• ISSN: 1671-4083; 1745-7254
• DOI: 10.1038/aps.2013.98

Aim: To investigate the effects of punicalagin, a polyphenol isolated from Punica granatum, on human U87MG glioma cells in vitro . Methods: The viability of human U87MG glioma cells was evaluated using MTT assay. Cell cycle was detected with flow cytometry analysis. The levels of Bcl-2, cleaved caspase-9, cleaved poly(ADP-ribose) polymerase (PARP), phosphor-AMPK and phosphor-p27 at Thr198 were measured using immunoblot analyses. Caspase-3 activity was determined with spectrophotometer. To determine autophagy, LC3 cleavage and punctate patterns were examined. Results: Punicalagin (1-30 μg/mL) dose-dependently inhibited the cell viability in association with increased cyclin E level and decreased cyclin B and cyclin A levels. The treatment also induced apoptosis as shown by the cleavage of PARP, activation of caspase-9, and increase of caspase-3 activity in the cells. However, pretreatment of the cells with the pan-caspase inhibitor z-DEVD-fmk (50 μmol/L) did not completely prevent the cell death. On the other hand, punicalagin treatment increased LC3-II cleavage and caused GFP-LC3-II-stained punctate pattern in the cells. Suppressing autophagy of cells with chloroquine (1-10 μmol/L) dose-dependently alleviated the cell death caused by punicalagin. Punicalagin (1-30 μg/mL) also increased the levels phosphor-AMPK and phosphor-p27 at Thr198 in the cells, which were correlated with the induction of autophagic cell death. Conclusion: Punicalagin induces human U87MG glioma cell death through both apoptotic and autophagic pathways.