Cisplatin exposure causes c-Myc-dependent resistance to CDK4/6 inhibition in HPV-negative head and neck squamous cell carcinoma

Cell Death Dis. 2019 Nov 14;10(11):867. doi: 10.1038/s41419-019-2098-8.

Abstract

The loss of p16 is a signature event in Human Papilloma Virus (HPV)-negative head and neck squamous cell carcinoma (HNSCC) that leads to increased Cyclin Dependent Kinase 4/6 (CDK) signaling. Palbociclib, a CDK4/6 inhibitor, is active for the treatment of a subset of HNSCC. In this study, we analyzed patient response data from a phase I clinical trial of palbociclib in HNSCC and observed an association between prior cisplatin exposure and CDK inhibitor resistance. We studied the effects of palbociclib on cisplatin-sensitive and -resistant HNSCC cell lines. We found that while palbociclib is highly effective against chemo-naive HNSCC cell lines and tumor xenografts, prior cisplatin exposure induces intrinsic resistance to palbociclib in vivo, a relationship that was not observed in vitro. Mechanistically, in the course of provoking a DNA damage-resistance phenotype, cisplatin exposure upregulates both c-Myc and cyclin E, and combination treatment with palbociclib and the c-Myc bromodomain inhibitor JQ1 exerts a synergistic anti-growth effect in cisplatin-resistant cells. These data show the benefit of exploiting the inherent resistance mechanisms of HNSCC to overcome cisplatin- and palbociclib resistance through the use of c-Myc inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Cell Line, Tumor
  • Cetuximab / administration & dosage
  • Cisplatin / administration & dosage*
  • Cisplatin / adverse effects
  • Cyclin-Dependent Kinase 4 / genetics*
  • Drug Resistance, Neoplasm / drug effects
  • Female
  • Heterografts
  • Humans
  • Male
  • Mice
  • Papillomaviridae / genetics
  • Papillomaviridae / pathogenicity
  • Papillomavirus Infections / drug therapy
  • Papillomavirus Infections / genetics
  • Papillomavirus Infections / pathology
  • Protein Kinase Inhibitors / administration & dosage
  • Proto-Oncogene Proteins c-myc / genetics*
  • Squamous Cell Carcinoma of Head and Neck / drug therapy*
  • Squamous Cell Carcinoma of Head and Neck / genetics
  • Squamous Cell Carcinoma of Head and Neck / pathology

Substances

  • MYC protein, human
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins c-myc
  • CDK4 protein, human
  • Cyclin-Dependent Kinase 4
  • Cetuximab
  • Cisplatin