Matrix-metalloproteinases in head and neck carcinoma-cancer genome atlas analysis and fluorescence imaging in mice

Otolaryngol Head Neck Surg. 2014 Oct;151(4):612-8. doi: 10.1177/0194599814545083. Epub 2014 Aug 4.

Abstract

Objective: (1) Obtain matrix-metalloproteinase (MMP) expression profiles for head and neck squamous cell carcinoma (HNSCC) specimens from the Cancer Genomic Atlas (TCGA). (2) Demonstrate HNSCC imaging using MMP-cleavable, fluorescently labeled ratiometric activatable cell-penetrating peptide (RACPP).

Study design: Retrospective human cohort study; prospective animal study.

Setting: Translational research laboratory.

Subjects and methods: Patient clinical data and mRNA expression levels of MMP genes were downloaded from TCGA data portal. RACPP provides complementary ratiometric fluorescent contrast (increased Cy5 and decreased Cy7 intensities) when cleaved by MMP2/9. HNSCC-tumor bearing mice were imaged in vivo after RACPP injection. Histology was evaluated by a pathologist blinded to experimental conditions. Zymography confirmed MMP-2/9 activity in xenografts. RACPP was applied to homogenized human HNSCC specimens, and ratiometric fluorescent signal was measured on a microplate reader for ex vivo analysis.

Results: Expression of multiple MMPs including MMP2/9 is greater in patient HNSCC tumors than matched control tissue. In patients with human papilloma virus positive (HPV+) tumors, higher MMP2 and MMP14 expression correlates with worse 5-year survival. Orthotopic tongue HNSCC xenografts showed excellent ratiometric fluorescent labeling with MMP2/9-cleavable RACPP (sensitivity = 95.4%, specificity = 95.0%). Fluorescence ratios were greater in areas of higher tumor burden (P < .03), which is useful for intraoperative margin assessment. Ex vivo, human HNSCC specimens showed greater cleavage of RACPP when compared to control tissue (P = .009).

Conclusions: Human HNSCC tumors show increased mRNA expression of multiple MMPs including MMP2/9. We used RACPP, a ratiometric fluorescence assay of MMP2/9 activity, to show improved occult tumor identification and margin clearance. Ex vivo assays using RACPP in biopsy specimens may identify patients who will benefit from intraoperative RACPP use.

Keywords: fluorescence imaging; head and neck squamous cell carcinoma; human papilloma virus; the Cancer Genomic Atlas.

Publication types

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

MeSH terms

  • Animals
  • Carcinoma, Squamous Cell / enzymology*
  • Carcinoma, Squamous Cell / mortality
  • Carcinoma, Squamous Cell / virology
  • Cell Line, Tumor
  • Cell-Penetrating Peptides
  • Disease Models, Animal
  • Head and Neck Neoplasms / enzymology*
  • Head and Neck Neoplasms / mortality
  • Head and Neck Neoplasms / virology
  • Humans
  • Matrix Metalloproteinases / genetics
  • Matrix Metalloproteinases / metabolism*
  • Mice
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Neoplasm Transplantation
  • Optical Imaging
  • Papillomaviridae
  • RNA, Messenger / metabolism
  • Retrospective Studies
  • Squamous Cell Carcinoma of Head and Neck

Substances

  • Cell-Penetrating Peptides
  • Neoplasm Proteins
  • RNA, Messenger
  • Matrix Metalloproteinases