Inhibition of Autophagy Potentiated the Antitumor Effect of Nedaplatin in Cisplatin-Resistant Nasopharyngeal Carcinoma Cells

PLoS One. 2015 Aug 19;10(8):e0135236. doi: 10.1371/journal.pone.0135236. eCollection 2015.

Abstract

Nedaplatin, a cisplatin analog, was developed to reduce the toxicity of cisplatin, whereas it can be cross-resistant with cisplatin in some circumstances. This study aimed to investigate the role of autophagy in nedaplatin induced cell death in cisplatin-resistant nasopharyngeal carcinoma cells. Here, we showed that HNE1/DDP and CNE2/DDP cells were resistant to nedaplatin-induced cell death with reduced apoptotic activity. Nedaplatin treatment resulted in autophagosome accumulation and increased expression of LC3-II, indicating the induction of autophagy by nedaplatin in HNE1/DDP and CNE2/DDP cells. Inhibition of autophagy by Bafilomycin A1 (Baf A1) and 3-Methyladenine (3-MA) remarkably enhanced the antitumor efficacy of nedaplatin in HNE1/DDP and CNE2/DDP cells, suggesting that the resistance to nedaplatin-induced cell death was caused by enhanced autophagy in nedaplatin-resistant NPC cells. Additionally, Baf A1 enhanced reactive oxygen species (ROS) generation and apoptosis induced by nedaplatin in HNE1/DDP cells. Mechanistically, nedaplatin treatment caused activation of ERK1/2 and suppression of Akt/mTOR signaling pathways. While inhibition of ERK1/2 by MEK1/2 inhibitor, U0126, could reduce the expression of LC3-II in nedaplatin-resistant NPC cells. Furthermore, suppression of ROS could inhibit nedaplatin-induced ERK activation in HNE1/DDP cells, indicating that ROS and ERK were involved in nedaplatin-induced autophagy. Together, these findings suggested that autophagy played a cytoprotective role in nedaplatin-induced cytotoxicity of HNE1/DDP and CNE2/DDP cells. Furthermore, our results highlighted a potential approach to restore the sensitivity of cisplatin-resistant nasopharyngeal cancer cells to nedaplatin in combination with autophagy inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Autophagy / drug effects*
  • Butadienes / pharmacology
  • Carcinoma
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Survival
  • Cisplatin / pharmacology
  • Drug Resistance, Neoplasm / physiology*
  • Enzyme Activation / drug effects
  • Extracellular Signal-Regulated MAP Kinases / antagonists & inhibitors
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Humans
  • Macrolides / pharmacology
  • Microtubule-Associated Proteins / biosynthesis
  • Nasopharyngeal Carcinoma
  • Nasopharyngeal Neoplasms / drug therapy
  • Nasopharyngeal Neoplasms / pathology*
  • Nitriles / pharmacology
  • Organoplatinum Compounds / pharmacology*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • Antineoplastic Agents
  • Butadienes
  • MAP1LC3A protein, human
  • Macrolides
  • Microtubule-Associated Proteins
  • Nitriles
  • Organoplatinum Compounds
  • Reactive Oxygen Species
  • U 0126
  • 3-methyladenine
  • bafilomycin A1
  • nedaplatin
  • MTOR protein, human
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • Extracellular Signal-Regulated MAP Kinases
  • Adenine
  • Cisplatin

Grants and funding

This study was supported by funds from National Key Basic Research Program of China (2015CB931800), Shanghai Science and Technology Commission (13431900303); and Shanghai Health and Family Planning Commission (2013012). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.