ZNF32 contributes to the induction of multidrug resistance by regulating TGF-β receptor 2 signaling in lung adenocarcinoma

Cell Death Dis. 2016 Oct 20;7(10):e2428. doi: 10.1038/cddis.2016.328.

Abstract

Multidrug resistance (MDR) is one of the most important contributors to the high mortality of cancer and remains a major concern. We previously found that zinc finger protein 32 (ZNF32), an important transcription factor associated with cancer in Homo sapiens, protects tumor cells against cell death induced by oxidative stress and other stimuli. We thus hypothesized that ZNF32 might enable the tolerance of cancer cells to anti-tumor drugs because higher ZNF32 expression has been found in cancer tissues and in drug-resistant lung adenocarcinoma (AC) cells. In this study, we found that ZNF32 is upregulated by Sp1 (specificity protein 1) in response to drug treatment and that ZNF32 promotes drug resistance and protects AC cells against cisplatin or gefitinib treatment. ZNF32 overexpression in AC cells conferred resistance to EGFR (epidermal growth factor receptor) inhibitors by enhancing MEK/ERK activation. Moreover, ZNF32 was found to directly bind to the TGF-βR2 (transforming growth factor-beta receptor 2) promoter to promote its expression, and ZNF32-induced resistance was mediated by enhancing TGF-βR2 expression and activating the TGF-βR2/SMAD2 pathway. In both a mouse model and ex vivo cultured patient samples, a high level of ZNF32 expression was closely associated with worse overall survival and cisplatin resistance. ZNF32 appears to be a potential inducer of drug resistance that could increase the expression of the drug resistance-associated gene TGF-βR2 and subsequently facilitate the induction of drug resistance during both conventional chemotherapy and novel target therapy. Thus, ZNF32-associated target therapy is a potential novel adjuvant therapy that might effectively prevent the occurrence of multidrug resistance (MDR) during chemotherapy and improve the survival of patients with AC.

MeSH terms

  • Adenocarcinoma / metabolism*
  • Adenocarcinoma / pathology
  • Adenocarcinoma of Lung
  • Cell Line, Tumor
  • Drug Resistance, Multiple*
  • Drug Resistance, Neoplasm*
  • Drug Synergism
  • HEK293 Cells
  • Humans
  • Kruppel-Like Transcription Factors / metabolism*
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / pathology
  • Protein Serine-Threonine Kinases / metabolism*
  • Receptor, Transforming Growth Factor-beta Type II
  • Receptors, Transforming Growth Factor beta / metabolism*
  • Signal Transduction*
  • Sp1 Transcription Factor / metabolism
  • Survival Analysis
  • Transforming Growth Factor beta / metabolism
  • Up-Regulation

Substances

  • Kruppel-Like Transcription Factors
  • Receptors, Transforming Growth Factor beta
  • Sp1 Transcription Factor
  • Transforming Growth Factor beta
  • ZNF32 protein, human
  • Protein Serine-Threonine Kinases
  • Receptor, Transforming Growth Factor-beta Type II