ASC modulates HIF-1α stability and induces cell mobility in OSCC

Cell Death Dis. 2020 Sep 3;11(9):721. doi: 10.1038/s41419-020-02927-7.

Abstract

High-level expression of ASC (Apoptosis-associated speck-like protein containing a CARD) leads to lymph node metastasis in OSCC, but the underlying mechanism remains unclear. Here, we show that HIF-1α participates in ASC-induced metastasis. We identified 195 cell-motion-associated genes that were highly activated in ASC-overexpressed SAS_ASC cells; of them, 14 representative genes were found to be overexpressed in OSCC tissues in our previously reported RNA-seq dataset, OSCC-Taiwan. Nine of the 14 genes were also upregulated in OSCC-TCGA samples. Among the nine genes, RRAS2, PDGFA, and VEGFA, were correlated with poor overall survival of patients in OSCC-TCGA dataset. We further demonstrated that the promoters of these 14 ASC-induced genes contained binding motifs for the transcription-regulating factor, HIF-1α. We observed that ASC interacted with and stabilized HIF-1α in both the cytoplasm and the nucleus under normoxia. Molecules involved in the HIF-1α pathway, such as VHL and PHD2, showed no difference in their gene and protein levels in the presence or absence of ASC, but the expression of HIF-1α-OH, and the ubiquitination of HIF-1α were both decreased in SAS_ASC cells versus SAS_con cells. The migration and invasion activities of SAS_ASC cells were reduced when cells were treated with the HIF-1α synthesis inhibitor, digoxin. Taken together, our results demonstrate that the novel ASC-HIF-1α regulatory pathway contributes to lymph node metastasis in OSCC, potentially suggesting a new treatment strategy for OSCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CARD Signaling Adaptor Proteins / metabolism*
  • Cell Line, Tumor
  • Cell Movement / physiology
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Lymphatic Metastasis
  • Mouth Neoplasms / genetics
  • Mouth Neoplasms / metabolism*
  • Mouth Neoplasms / pathology
  • Squamous Cell Carcinoma of Head and Neck / metabolism*
  • Squamous Cell Carcinoma of Head and Neck / pathology
  • Tumor Microenvironment
  • Up-Regulation

Substances

  • CARD Signaling Adaptor Proteins
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • PYCARD protein, human