NQO1-Mediated Tumor-Selective Lethality and Radiosensitization for Head and Neck Cancer

Mol Cancer Ther. 2016 Jul;15(7):1757-67. doi: 10.1158/1535-7163.MCT-15-0765. Epub 2016 Apr 12.

Abstract

Ionizing radiation (IR) is a key therapeutic regimen for many head and neck cancers (HNC). However, the 5-year overall survival rate for locally advanced HNCs is approximately 50% and better therapeutic efficacy is needed.

Nad(p)h: quinone oxidoreductase 1 (NQO1) is overexpressed in many cancers, and β-lapachone (β-lap), a unique NQO1 bioactivatable drug, exploits this enzyme to release massive reactive oxygen species (ROS) that synergize with IR to kill by programmed necrosis. β-Lap represents a novel therapeutic opportunity in HNC leading to tumor-selective lethality that will enhance the efficacy of IR. Immunohistochemical staining and Western blot assays were used to assess the expression levels of NQO1 in HNC cells and tumors. Forty-five percent of endogenous HNCs expressed elevated NQO1 levels. In addition, multiple HNC cell lines and tumors demonstrated elevated levels of NQO1 expression and activity and were tested for anticancer lethality and radiosensitization by β-lap using long-term survival assays. The combination of nontoxic β-lap doses and IR significantly enhanced NQO1-dependent tumor cell lethality, increased ROS, TUNEL-positive cells, DNA damage, NAD(+), and ATP consumption, and resulted in significant antitumor efficacy and prolonged survival in two xenograft murine HNC models, demonstrating β-lap radiosensitization of HNCs through a NQO1-dependent mechanism. This translational study offers a potential biomarker-driven strategy using NQO1 expression to select tumors susceptible to β-lap-induced radiosensitization. Mol Cancer Ther; 15(7); 1757-67. ©2016 AACR.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Catalase / genetics
  • Catalase / metabolism
  • Cell Death / drug effects
  • Cell Death / genetics
  • Cell Line, Tumor
  • Cell Survival / genetics
  • Cell Survival / radiation effects
  • Disease Models, Animal
  • Enzyme Activation
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Expression*
  • Head and Neck Neoplasms / drug therapy
  • Head and Neck Neoplasms / genetics*
  • Head and Neck Neoplasms / metabolism
  • Head and Neck Neoplasms / pathology
  • Humans
  • NAD(P)H Dehydrogenase (Quinone) / genetics*
  • NAD(P)H Dehydrogenase (Quinone) / metabolism
  • Naphthoquinones / pharmacology
  • Radiation Tolerance / genetics*
  • Radiation, Ionizing*
  • Radiation-Sensitizing Agents / pharmacology
  • Reactive Oxygen Species / metabolism
  • Survival Analysis
  • Xenograft Model Antitumor Assays

Substances

  • Naphthoquinones
  • Radiation-Sensitizing Agents
  • Reactive Oxygen Species
  • beta-lapachone
  • Adenosine Triphosphate
  • Catalase
  • NAD(P)H Dehydrogenase (Quinone)
  • NQO1 protein, human