[Frontiers in Bioscience E3, 1221-1228, June 1, 2011]

NADPH treatment decreases C6 glioma cell survival by increasing oxidative stress

Yingxin Ma1, Heyu Chen1, Cuiping Zhao1, Weiliang Xia1, Weihai Ying1,2

1Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, P.R. China, 2Institute of Neurology, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, P.R. China

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Materials
3.2. Cell cultures
3.3. Lactate dehydrogenase (LDH) assay
3.4. Determinations of nuclear condensation
3.5. Flow cytometry-based propidium iodide (PI) staining
3.6. Trypan blue assay
3.7. Dihydroethidium (DHE) assay
3.8. Statistical analyses
4. Results
4.1. NADPH treatment can dose-dependently decrease the survival of C6 glioma cells
4.2. Oxidative stress mediates the effects of NADPH on C6 glioma cell survival
4.3. NADPH oxidase and PARP play significant roles in the effects of NADPH on C6 glioma cell survival
4.4. Altered calcium homeostasis is involved in the effects of NADPH on C6 glioma cell survival
5. Discussion
6. Acknowledgments
7. References

1. ABSTRACT

NADPH (nicotinamide adenine dinucleotide phosphate, reduced form) plays pivotal roles in antioxidation and reductive biosynthesis. However, the effect of NADPH treatment on cell survival is unknown. In this study, we determined the effect of NADPH treatment on the survival of glioma cells. Treatment of C6 glioma cells with as low as 1 mM NADPH for 24 hrs induced a significant decrease in the survival of the glioma cells, while NADPH treatment had no effect on the survival of primary astrocyte cultures. We also found that NADPH treatment increased intracellular oxidative stress. Three antioxidants and the NADPH oxidase inhibitor, apocynin, attenuated the effect of NADPH. Poly(ADP-ribose) polymerase (PARP) activation appears to be a downstream effector of the oxidative stress, since PARP inhibitors reduced the effect of NADPH. Calcium chelator, BAPTA-AM, also attenuated the effect of NADPH. Collectively, these data indicate a novel property of NADPH: NADPH decreases glioma cell survival by inducing the NADPH oxidase-dependent increase in oxidative stress and by PARP activation. These results also suggest a potential therapeutic effect of NADPH on gliomas.