Stem cell marker (Nanog) and Stat-3 signaling promote MicroRNA-21 expression and chemoresistance in hyaluronan/CD44-activated head and neck squamous cell carcinoma cells

Oncogene. 2012 Jan 12;31(2):149-60. doi: 10.1038/onc.2011.222. Epub 2011 Jun 20.


MicroRNAs are often associated with the pathogenesis of many cancers, including head and neck squamous cell carcinoma (HNSCC). In particular, microRNA-21 (miR-21) appears to have a critical role in tumor cell survival, chemoresistance and HNSCC progression. In this study, we investigated matrix hyaluronan (HA)-induced CD44 (a primary HA receptor) interaction with the stem cell markers, Nanog and Stat-3, in HNSCC cells (HSC-3 cells). Our results indicate that HA binding to CD44 promotes Nanog-Stat-3 (also tyrosine phosphorylated Stat-3) complex formation, nuclear translocation and transcriptional activation. Further analyses reveal that miR-21 is controlled by an upstream promoter containing Stat-3 binding site(s), while chromatin immunoprecipitation assays demonstrate that stimulation of miR-21 expression by HA/CD44 signaling is Nanog/Stat-3-dependent in HNSCC cells. This process results in a decrease of a tumor suppressor protein (PDCD4), and an upregulation of i nhibitors of the apoptosis family of proteins (IAPs) as well as chemoresistance in HSC-3 cells. Treatment of HSC-3 cells with Nanog- and/or Stat-3-specific small interfering RNAs effectively blocks HA-mediated Nanog-Stat-3 signaling events, abrogates miR-21 production and increases PDCD4 expression. Subsequently, this Nanog-Stat-3 signaling inhibition causes downregulation of survival protein (IAP) expression and enhancement of chemosensitivity. To further evaluate the role of miR-21 in tumor cell-specific functions, HSC-3 cells were also transfected with a specific anti-miR-21 inhibitor in order to silence miR-21 expression and block its target functions. Our results demonstrate that anti-miR-21 inhibitor not only upregulates PDCD4 expression but also decreases IAP expression and enhances chemosensitivity in HA-treated HNSCC cells. Together, these findings indicate that the HA-induced CD44 interaction with Nanog and Stat-3 has a pivotal role in miR-21 production leading to PDCD4 reduction, IAP upregulation and chemoresistance in HNSCC cells. This novel Nanog/Stat-3 signaling pathway-specific mechanism involved in miR-21 production is significant for the formation of future intervention strategies in the treatment of HA/CD44-activated HNSCC.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / metabolism*
  • Carcinoma, Squamous Cell / pathology
  • Cell Line, Tumor
  • Cell Nucleus / metabolism
  • Drug Resistance, Neoplasm*
  • Head and Neck Neoplasms / genetics
  • Head and Neck Neoplasms / metabolism*
  • Head and Neck Neoplasms / pathology
  • Homeodomain Proteins / metabolism*
  • Humans
  • Hyaluronan Receptors / metabolism*
  • Hyaluronic Acid / metabolism*
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Nanog Homeobox Protein
  • Promoter Regions, Genetic
  • STAT3 Transcription Factor / metabolism*
  • Signal Transduction*


  • Homeodomain Proteins
  • Hyaluronan Receptors
  • MIRN21 microRNA, human
  • MicroRNAs
  • NANOG protein, human
  • Nanog Homeobox Protein
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Hyaluronic Acid