Malignant melanoma cells acquire resistance to DNA interstrand cross-linking chemotherapeutics by p53-triggered upregulation of DDB2/XPC-mediated DNA repair

Oncogene. 2014 Apr 10;33(15):1964-74. doi: 10.1038/onc.2013.141. Epub 2013 Apr 22.

Abstract

Malignant melanoma is a cancer characterized by high chemoresistance although p53 is rarely mutated. Here, we show that p53 wild-type melanoma cells acquire resistance to cell death induced by fotemustine (FM), which is a representative of alkylating DNA interstrand cross-linking agents used in melanoma therapy. We show that drug-induced resistance is a result of p53-dependent upregulation of the nucleotide excision repair (NER) genes xeroderma pigmentosum complementation group C (XPC) and damaged DNA-binding protein 2 (DDB2), which stimulate the repair of DNA interstrand cross-links (ICLs) arising from O(6)-chloroethylguanine. Consequently, TP53 mutated cells are unable to repair ICLs, leading to prolonged ATM, ATR and checkpoint kinase 1 (CHK1) activation, and finally apoptosis. The roles of p53 and NER in ICL-triggered cell death were confirmed by knockdown of p53 and XPC. Upregulation of XPC and DDB2 in p53wt cells following a single drug treatment is a robust and sustained response that lasts for up to 1 week. Pretreatment with an inducing dose followed by a high and toxic dose of FM provoked an adaptive response as the killing outcome of the challenge dose was reduced. Upregulation of XPC and DDB2 was also observed in a melanoma mouse xenograft model following systemic administration of FM. Additionally, XPC and DDB2 induction occurred upon treatment with other cross-linking anticancer drugs, such as cisplatin and mafosfamide, indicating it is a general response of cancer cells to this group of chemotherapeutics. Collectively, the data indicate that p53-dependent upregulation of XPC and DDB2 is a key mechanism upon genotoxic stress, whereby melanoma cells acquire resistance towards DNA cross-linking agents. To our knowledge, this is the first demonstration of upregulation of NER following a single dose of a DNA interstrand cross-linker, which is a robust and long-lasting effect that impacts the killing response of cancer cells to subsequent treatments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Cell Line, Tumor
  • DNA Damage / genetics
  • DNA Repair / genetics*
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / genetics
  • Drug Resistance, Neoplasm / genetics*
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Neoplastic
  • Heterografts
  • Humans
  • Immunoblotting
  • Melanoma / genetics*
  • Melanoma / metabolism
  • Mice
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*
  • Up-Regulation

Substances

  • Antineoplastic Agents
  • DDB2 protein, human
  • DNA-Binding Proteins
  • Tumor Suppressor Protein p53
  • XPC protein, human