Curcumin enhances cisplatin-induced human laryngeal squamous cancer cell death through activation of TRPM2 channel and mitochondrial oxidative stress

Abstract

In this study, laryngeal tumor cells were killed through the production of excessive reactive oxygen species (ROS) and Ca2+ influx by cisplatin (CISP). Nevertheless, a resistance was determined against CISP treatment in the tumor cells. We have investigated the stimulating role of curcumin (CURC) on CISP-induced human laryngeal squamous cancer (Hep2) cell death through TRPM2 channel activation, and its protective role against the adverse effects of CISP in normal kidney (MPK) cells. Hep2 and MPK cells were divided into four groups as control group, CURC group (10μM for 24 hrs), CISP group (25 μM for 24 hrs), and CURC + CISP combination group. CISP-induced decrease of cell viability, cell count, glutathione peroxidase and glutathione level in Hep2 cells were further increased by CURC treatment, but the CISP-induced normal MPK cell death was reduced by the treatment. CISP-induced increase of apoptosis, Ca2+ fluorescence intensity, TRPM2 expression and current densities through the increase of lipid peroxidation, intracellular and mitochondrial oxidative stress were stimulated by CURC treatment. In conclusion, CISP-induced increases in mitochondrial ROS and cell death levels in Hep2 cells were further enhanced through the increase of TRPM2 activation with the effect of CURC treatment. CISP-induced drug resistance in Hep2 cells might be reduced by CURC treatment.

Resveratrol attenuates hypoxia-induced neuronal cell death, inflammation and mitochondrial oxidative stress by modulation of TRPM2 channel

“…Free Zn 2+ has apoptosis and oxidant actions via accumulation in the mitochondria for neurons 27 . Hence, intracellular free Zn 2+ depletion causes decrease in mitochondria ROS generation, caspase activities and [Ca 2+ ] i concentrations via increase of rGSH and GPx antioxidant levels in the renal collecting duct cells 45 . It is well known that grape products contain rich amount of RSV and hepatoprotective effect of grape seed oil against carbon tetrachloride-induced oxidative stress, Zn 2+ accumulation, rGSH depletion, apoptosis, caspase-3 activation in radiation exposed rats were recently reported 46 .…”

“…We investigated RSV-induced TRPM2 potentiation in the SH-SY5Y neurons and HEK293 cells by LSC microscope (LSM800, Zeiss, Ankara, Turkey) analyses as described in previous studies 45,49 . The cells were seeded 35 mm glass bottom dishes (Mattek Corporation Inc., Ashland, MA, USA) before the analyses.…”

“…Microplate reader assay of cell viability (MTT). Viability assays were performed by measuring mitochondrial reductase activity with MTT [3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide] (Sigma-Aldrich, Istanbul, Turkey) as described in previous studies 34,45,49 . Cells from the four groups were incubated in MTT solution (0.5 mg/ml) for 15 min and the media were removed.…”

“…For detecting the apoptosis level, we used a commercial kit (Biocolor Ltd., Northern Ireland) and the analyses were performed in a spectrophotometer (UV-1800, Shimadzu, Kyoto, Japan). Details of the apoptosis analyses were given in instructions of Biocolor Ltd. and elsewhere 45,49 .…”

“…To determine caspase-3 and −9 activity, the neurons in the control and treated with ACA groups were incubated with 2 ml of substrate solution for 1 h at 37 °C as previously described 45,49 . For assay of caspase-3 and −9 activities, cleavages of fluorogenic substrates (AC-DEVD-AMC for caspase −3 and ACDEVD-AMC for caspase-9) (Bachem, Bubendorf, Switzerland) were used.…”