Targeting HPV16 E6-p300 interaction reactivates p53 and inhibits the tumorigenicity of HPV-positive head and neck squamous cell carcinoma

Oncogene. 2014 Feb 20;33(8):1037-46. doi: 10.1038/onc.2013.25. Epub 2013 Mar 11.


The incidence of human papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HNSCC) has rapidly increased over the past 30 years, prompting the suggestion that an epidemic maybe on the horizon. Therefore, there is a clinical need to develop alternate therapeutic strategies to manage the growing number of HPV-positive HNSCC patients. High-risk HPV E6 inactivates p53 through two distinct mechanisms; association with E6AP to degrade p53 and association with p300 to block p300-mediated p53 acetylation and activation. In this study, we determined if targeting the E6-p300 interaction is an effective approach to reactivate p53 in HPV-positive HNSCC. Ectopic expression of the CH1 domain of p300 in HPV-positive HNSCC blocks the association between E6 and p300, increases total and acetylated p53 levels and enhances p53 transcriptional activity. Moreover, expression of p21, miR-34a and miR-200c are increased, demonstrating functional p53 reactivation. CH1 overexpression in HPV-positive HNSCC has a global anticancer effect resulting in a decrease in cell proliferation and clonogenic survival and an increase in apoptosis. The in vivo tumor-initiating ability of HPV-positive HNSCC is severely compromised with CH1 overexpression, in part through a reduction in the cancer-initiating cell population. A novel small-molecule CH1 inhibitor, CH1iB, reactivates p53 and potentiates the anticancer activity of cis-platinum in HPV-positive HNSCC cells. Our work shows that CH1-domain inhibitors represent a novel class of p53-reactivation therapeutics for managing HPV-positive HNSCC patients.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alphapapillomavirus / isolation & purification*
  • Carcinoma, Squamous Cell / metabolism*
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / virology
  • Head and Neck Neoplasms / metabolism*
  • Head and Neck Neoplasms / pathology
  • Head and Neck Neoplasms / virology
  • Humans
  • Oncogene Proteins, Viral / metabolism*
  • Repressor Proteins / metabolism*
  • Tumor Suppressor Protein p53 / metabolism*
  • p300-CBP Transcription Factors / metabolism*


  • E6 protein, Human papillomavirus type 16
  • Oncogene Proteins, Viral
  • Repressor Proteins
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • p300-CBP Transcription Factors
  • p300-CBP-associated factor