Resveratrol Enhances Apoptotic and Oxidant Effects of Paclitaxel through TRPM2 Channel Activation in DBTRG Glioblastoma Cells

Abstract

Numerous studies have reported a strong association between increased production of reactive oxygen species (ROS) and the pathobiology of several diseases, and cancer in particular. Therefore, manipulation of cellular oxidative stress levels represents an important therapeutic target. Recently, resveratrol (RESV), a naturally occurring phytochemical, has been shown to sensitize several cell lines to the anticancer effects of other chemotherapeutic agents, including paclitaxel (PAX). However, the molecular mechanisms of action of RESV through oxidative sensitive TRPM2 channel activation remain unclear. The aim of this study was to evaluate the effect of combination therapy of RESV and PAX on activation of TRPM2 in DBTRG glioblastoma cells. DBTRG cells were divided into four treatment groups: control, RESV (50 μM), PAX (50 μM), and PAX + RESV for 24 hours. Our data shows that markers for apoptosis, mitochondrial membrane depolarization and mitochondrial function, intracellular steady-state ROS levels, caspase 3 activity, TRPM2 current density, and Ca2+ florescence intensity were significantly increased in DBTRG cells following treatment with PAX and RESV, respectively, although cell viability was also decreased by these treatments. These biochemical markers were further increased to favor the anticancer effects of PAX in DBTRG cells in combination with RESV. The PAX and RESV-mediated increase in current density and Ca2+ florescence intensity was decreased with a TRPM2 blocker. This suggests that for this combination therapy to have a substantial effect on apoptosis and cell viability, the TRPM2 channel must be stimulated.

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

“…However, we observed decrease of rGSH level and GPx activity in the SH-SY5Y cells exposed to HYPX, which were upregulated by the RSV treatment. These data are agreement with previous results showing decreased oxidation of thiol redox system members in the SH-SY5Y cells after RSV treatment, providing evidence for a protective effect of RSV through upregulation of rGSH and GPx in diminishing neuronal oxidative stress and inflammation during HYPX 3,24 . The observed decreases in ROS and MDA upon exposure of HYPX may therefore be due to the increase repair of respiratory chain enzyme complex activity through upregulation of rGSH and GPx redox system in the mitochondria of SH-SY5Y cells.…”

“…In the present study, we observed modulation of the TRPM2 channel via inhibition excessive ROS generation and increase of thiol redox cycle antioxidants (rGSH and GPx) in the HYPX-induced SH-SY5Y cell by the RSV and TRPM2 channel blocker (ACA and 2-APB) treatments. Similarly, we recently observed a modulator action of RSV on the TRPM2 channel activity in the DBTRG glioblastoma cells 24 .…”

“…In the present literature data, there is no report on the protective action of RSV against TRPM2 activation in cells during the HYPX. However, the results of our previous study indicated that RSV modulates mitochondrial biogenesis and apoptosis in DBTRG neuroblastoma cells via upregulation of TRPM2 channel activation and ROS generation during HYPX 24 . We found that RSV treatment of the SH-SY5Y neuronal cells subjected to CoCl 2 -induced HYPX modulated the structural membrane depolarization integrity and enhanced biogenesis of mitochondria and restored mitochondrial and cytosolic ROS generation functions via modulation of TRPM2.…”

“…Accumulating evidences suggest that HYPX induced death and apoptosis is mainly through the increase of TRPM2 activation in the neurons such as DBTRG glioblastoma and hippocampus 10,24 . However, there www.nature.com/scientificreports www.nature.com/scientificreports/ is no report on the neurotoxicity and neuronal death in the CoCl 2 -treated SH-SY5Y neurons.…”

“…Hence, we propose that modulation of TRPM2 in the RSV treatment might represent a mechanism controlling adverse neurotoxicity actions in the SH-SY5Y neuronal cells with hypoxia. One of the well-known hypoxia mimetic agents through inhibition of cellular oxygen uptake in cell line models is cobalt chloride (CoCl 2 ) 17,23,24 . It has been used in SH-SY5Y cell model for induction of hypoxia (HYPX).…”