Forkhead box K2 promotes human colorectal cancer metastasis by upregulating ZEB1 and EGFR

Theranostics. 2019 May 31;9(13):3879-3902. doi: 10.7150/thno.31716. eCollection 2019.

Abstract

Background: Metastasis is the major reason for high recurrence rates and poor survival among patients with colorectal cancer (CRC). However, the underlying molecular mechanism of CRC metastasis is unclear. This study aimed to investigate the role of forkhead box K2 (FOXK2), one of the most markedly increased FOX genes in CRC, and the mechanism by which it is deregulated in CRC metastasis. Methods: FOXK2 levels were analyzed in two independent human CRC cohorts (cohort I, n = 363; cohort II, n = 390). In vitro Transwell assays and in vivo lung and liver metastasis models were used to examine CRC cell migration, invasion and metastasis. Chromatin immunoprecipitation and luciferase reporter assays were used to measure the binding of transcription factors to the promoters of FOXK2, zinc finger E-box binding homeobox 1 (ZEB1) and epidermal growth factor receptor (EGFR). Cetuximab was utilized to treat FOXK2-mediated metastatic CRC. Results: FOXK2 was significantly upregulated in human CRC tissues, was correlated with more aggressive features and indicated a poor prognosis. FOXK2 overexpression promoted CRC migration, invasion and metastasis, while FOXK2 downregulation had the opposite effects. ZEB1 and EGFR were determined to be direct transcriptional targets of FOXK2 and were essential for FOXK2-mediated CRC metastasis. Moreover, activation of EGFR signaling by EGF enhanced FOXK2 expression via the extracellular regulated protein kinase (ERK) and nuclear factor (NF)-κB pathways. The EGFR monoclonal antibody cetuximab significantly inhibited FOXK2-promoted CRC metastasis. In clinical CRC tissues, FOXK2 expression was positively correlated with the expression of p65, ZEB1 and EGFR. CRC patients who coexpressed p65/FOXK2, FOXK2/ZEB1 and FOXK2/EGFR had poorer prognosis. Conclusions: FOXK2 serves as a prognostic biomarker in CRC. Cetuximab can block the EGF-NF-κB-FOXK2-EGFR feedback loop and suppress CRC metastasis.

Keywords: Forkhead box K2; cetuximab; colorectal cancer; epidermal growth factor receptor; metastasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Animals
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Movement / genetics
  • Cetuximab / pharmacology
  • Cetuximab / therapeutic use
  • Cohort Studies
  • Colorectal Neoplasms / drug therapy
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / pathology*
  • Epithelial-Mesenchymal Transition / drug effects
  • Epithelial-Mesenchymal Transition / genetics
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism
  • Female
  • Forkhead Transcription Factors / metabolism*
  • Gene Expression Regulation, Neoplastic* / drug effects
  • Humans
  • MAP Kinase Signaling System / drug effects
  • Male
  • Mice, Inbred BALB C
  • Mice, Nude
  • Multivariate Analysis
  • NF-kappa B / metabolism
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • Neoplasm Recurrence, Local / pathology
  • Prognosis
  • Survival Analysis
  • Transcriptional Activation / drug effects
  • Transcriptional Activation / genetics
  • Up-Regulation / drug effects
  • Up-Regulation / genetics*
  • Zinc Finger E-box-Binding Homeobox 1 / genetics*
  • Zinc Finger E-box-Binding Homeobox 1 / metabolism

Substances

  • Forkhead Transcription Factors
  • NF-kappa B
  • ZEB1 protein, human
  • Zinc Finger E-box-Binding Homeobox 1
  • interleukin binding factor
  • EGFR protein, human
  • ErbB Receptors
  • Cetuximab