Sensitivity to inhibition of DNA repair by Olaparib in novel oropharyngeal cancer cell lines infected with Human Papillomavirus

PLoS One. 2018 Dec 13;13(12):e0207934. doi: 10.1371/journal.pone.0207934. eCollection 2018.

Abstract

The incidence of Human Papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is increasing rapidly in the UK. Patients with HPV-positive OPSCC generally show superior clinical responses relative to HPV-negative patients. We hypothesised that these superior responses could be associated with defective repair of DNA double strand breaks (DSB). The study aimed to determine whether defective DNA repair could be associated with sensitivity to inhibition of DNA repair using the PARP inhibitor Olaparib. Sensitivity to Olaparib, and induction and repair of DNA damage, were assessed in a panel of 8 OPSCC cell-lines, including 2 novel HPV-positive lines. Effects on cell cycle distribution and levels of PARP1 and p53 were quantified. RNA-sequencing was used to assess differences in activity of DNA repair pathways. Two HPV-positive OPSCC lines were sensitive to Olaparib at potentially therapeutic doses (0.1-0.5 μM). Two HPV-negative lines were sensitive at an intermediate dose. Four other lines, derived from HPV-positive and HPV-negative tumours, were resistant to PARP inhibition. Only one cell-line, UPCISCC90, showed results consistent with the original hypothesis i.e. that in HPV-positive cells, treatment with Olaparib would cause accumulation of DSB, resulting in cell cycle arrest. There was no evidence that HPV-positive tumours exhibit defective repair of DSB. However, the data suggest that a subset of OPSCC may be susceptible to PARP-inhibitor based therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Carcinoma, Squamous Cell / drug therapy*
  • Carcinoma, Squamous Cell / metabolism
  • Carcinoma, Squamous Cell / virology
  • Cell Cycle Checkpoints / drug effects
  • Cell Line, Tumor
  • DNA Breaks, Double-Stranded
  • DNA Repair / drug effects*
  • Gene Expression Profiling
  • Humans
  • Oropharyngeal Neoplasms / drug therapy*
  • Oropharyngeal Neoplasms / metabolism
  • Oropharyngeal Neoplasms / virology
  • Papillomaviridae / pathogenicity*
  • Papillomavirus Infections / drug therapy*
  • Papillomavirus Infections / metabolism
  • Papillomavirus Infections / virology
  • Phthalazines / pharmacology*
  • Piperazines / pharmacology*
  • Poly (ADP-Ribose) Polymerase-1 / metabolism
  • Poly(ADP-ribose) Polymerase Inhibitors / pharmacology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • Antineoplastic Agents
  • Phthalazines
  • Piperazines
  • Poly(ADP-ribose) Polymerase Inhibitors
  • RNA, Messenger
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • PARP1 protein, human
  • Poly (ADP-Ribose) Polymerase-1
  • olaparib

Grants and funding

This study was supported by grant funding from Cancer Research Wales, Grant number CRW/201203. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.