Two-photon microscopy is effective in visualizing the spread of squamous cell carcinoma of the tongue, according to a study in the Journal of Visualized Experiments (July 25, 2011).
Orthotopic mouse models of oral cancer have been developed to facilitate the study of factors that impact invasion and serve as a model system for evaluating antitumor therapeutics, noted the study authors, from the Mary Babb Randolph Cancer Center at West Virginia University.
"In these systems, visualization of disseminated tumor cells within oral cavity tissues has typically been conducted by either conventional histology or with in vivo bioluminescent methods," they wrote. "A primary drawback of these techniques is the inherent inability to accurately visualize and quantify early tumor cell invasion arising from the primary site in three dimensions."
So they developed a protocol that combines an established model for squamous cell carcinoma of the tongue (SCOT) with two-photon imaging to allow multivectorial visualization of lingual tumor spread.
First, they engineered an OSC-19 head and neck tumor cell line to express the F-actin binding peptide LifeAct fused to the mCherry fluorescent protein. They then injected mice with these cells and found that this method reliably formed tumors on the tongue that could be visualized using two-photon microscopy.
This technique allows for the orthotopic visualization of tumor mass and locally invading cells in excised tongues without disrupting the regional tumor microenvironment, the authors noted. It also allows tumor cell invasion to be quantified by calculating the distances that invaded cells move from the primary tumor site.
"Overall this procedure provides an enhanced model system for analyzing factors that contribute to SCOT invasion and therapeutic treatments tailored to prevent local invasion and distant metastatic spread," the researchers concluded.
