Melatonin pre-treatment mitigates SHSY-5Y cells against oxaliplatin induced mitochondrial stress and apoptotic cell death

PLoS One. 2017 Jul 21;12(7):e0180953. doi: 10.1371/journal.pone.0180953. eCollection 2017.

Abstract

Oxaliplatin (Oxa) treatment to SH-SY5Y human neuroblastoma cells has been shown by previous studies to induce oxidative stress, which in turn modulates intracellular signaling cascades resulting in cell death. While this phenomenon of Oxa-induced neurotoxicity is known, the underlying mechanisms involved in this cell death cascade must be clarified. Moreover, there is still little known regarding the roles of neuronal mitochondria and cytosolic compartments in mediating Oxa-induced neurotoxicity. With a better grasp of the mechanisms driving neurotoxicity in Oxa-treated SH-SY5Y cells, we can then identify certain pathways to target in protecting against neurotoxic cell damage. Therefore, the purpose of this study was to determine whether one such agent, melatonin (Mel), could confer protection against Oxa-induced neurotoxicity in SH-SY5Y cells. Results from the present study found Oxa to significantly reduce SH-SY5Y cell viability in a dose-dependent manner. Alternatively, we found Mel pre-treatment to SH-SY5Y cells to attenuate Oxa-induced toxicity, resulting in a markedly increased cell viability. Mel exerted its protective effects by regulating reactive oxygen species (ROS) production and reducing superoxide radicals inside Oxa-exposed. In addition, we observed pre-treatment with Mel to rescue Oxa-treated cells by protecting mitochondria. As Oxa-treatment alone decreases mitochondrial membrane potential (Δψm), resulting in an altered Bcl-2/Bax ratio and release of sequestered cytochrome c, so Mel was shown to inhibit these pathways. Mel was also found to inhibit proteolytic activation of caspase 3, inactivation of Poly (ADP Ribose) polymerase, and DNA damage, thereby allowing SH-SY5Y cells to resist apoptotic cell death. Collectively, our results suggest a role for melatonin in reducing Oxa induced neurotoxicity. Further studies exploring melatonin's protective effects may prove successful in eliciting pathways to further alter the neurotoxic pathways of platinum compounds in cancer treatment.

MeSH terms

  • Antineoplastic Agents / toxicity*
  • Apoptosis / drug effects*
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Cytochromes c / metabolism
  • Dose-Response Relationship, Drug
  • Drug Evaluation, Preclinical
  • Humans
  • Melatonin / pharmacology*
  • Membrane Potential, Mitochondrial / drug effects
  • Membrane Potential, Mitochondrial / physiology
  • Mitochondria / drug effects*
  • Mitochondria / metabolism
  • Neuroprotective Agents / pharmacology*
  • Organoplatinum Compounds / toxicity*
  • Oxaliplatin
  • Oxidative Stress / drug effects
  • Oxidative Stress / physiology
  • Reactive Oxygen Species / metabolism
  • Superoxides / metabolism
  • bcl-2-Associated X Protein / metabolism

Substances

  • Antineoplastic Agents
  • BAX protein, human
  • Neuroprotective Agents
  • Organoplatinum Compounds
  • Reactive Oxygen Species
  • bcl-2-Associated X Protein
  • Oxaliplatin
  • Superoxides
  • Cytochromes c
  • Melatonin

Grants and funding

Dr. Mohammad Waseem was a recipient of a Senior Research Fellowship from University Grants Commission Basic Science Research [(UGC-BSR), Grant No.-F-7/91/2007). Dr. Heena Tabassum is grateful to Department of Science and Technology, Government of India, for financial grant (DST Cognitive Science Initiative Program, sanction no. SR/CSI/PDF-76/ 2012). The Grant no. [2016/001070/HS)], received as Extramural Research Grant from the Science and Engineering Research Board, New Delhi, Government of India, to Prof. Suhel Parvez is also thankfully acknowledged.