Piperlongumine inhibits cell growth and enhances TRAIL-induced apoptosis in prostate cancer cells

Objective: To investigate whether piperlongumine can sensitize prostate cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and trigger apoptosis in prostate cells.Methods: Human prostate cancer cell lines PC3, LNCaP, and VCaP were cultured with piperlongumine and TRAIL. Then, cell proliferation, migration, caspase activation, apoptotic protein expressions, and death receptor expressions were measured. Results: Piperlongumine inhibited cell proliferation at low doses (<10 μM) alone and in combination with TRAIL (25 ng/mL), induced apoptosis, and suppressed cyclooxygenase activation. Additionally, piperlongumine induced expression of death receptors which potentiated TRAIL-induced apoptosis in cancer cells but did not affect decoy receptors. Piperlongumine also downregulated tumor cell-survival pathways, inhibited colony formation and migration of cancer cells alone or in combination with TRAIL. The combination of piperlongumine with TRAIL was found to be synergistic. Conclusions: Our findings indicate that piperlongumine can sensitize cancer cells to TRAIL through the upregulation of death receptors and can trigger apoptosis with the downregulation of anti-apoptotic proteins.

Fluoride and aluminum release from restorative materials using ion chromatography

OBJECTIVE: The aim of this study was to determine the amounts of fluoride and aluminum released from different restorative materials stored in artificial saliva and double-distilled water. Material and METHODS: Cylindrical specimens (10 x 1 mm) were prepared from 4 different restorative materials (Kavitan Plus, Vitremer, Dyract Extra, and Surefil). For each material, 20 specimens were prepared, 10 of which were stored in 5 mL artificial saliva and 10 of which were stored in 5 mL of double-distilled water. Concentrations of fluoride and aluminum in the solutions were measured using ion chromatography. Measurements were taken daily for one week and then weekly for two additional weeks. Data were analyzed using two-way ANOVA and Duncan's multiple range tests (p<0.05). RESULTS: The highest amounts of both fluoride and aluminum were released by the resin-modified glass ionomer cement Vitremer in double-distilled water (p<0.05). All materials released significantly more fluoride in double-distilled water than in artificial saliva (p<0.05). In artificial saliva, none of the materials were observed to release aluminum. CONCLUSION: It was concluded that storage media and method of analysis should be taken into account when the fluoride and aluminum release from dental materials is assessed.