Cancer-associated fibroblasts: culprits or victims in cannibalism of oral squamous cell carcinoma cells?

The purpose of this study is to evaluate whether cancer-associated fibroblasts (CAF) promote cannibalistic activity of oral cancer cells and/or act as targets of these cells.

TCC has been described for more than a century through histomorphological analyses of cell-in-cell structures in tumours.

However, only in recent years, the improvement of 3D culture methods have allowed us to study the homotypic and heterotypic interactions that occur in the tumor microenvironment, associated with malignant tumour progression.

Recent reports in breast cancer have provided evidence that mesenchymal stem cells, which share several features with CAF, promote TCC and malignant behaviour in 3D co-cultures.

To date, little is known of the mechanisms underlying TCC in oral cancer, and nothing is known of the contribution of CAF.

Given the evidence that TCC selects and/or maintains a more aggressive malignant cell population, and, knowing that CAFs represent an abundant population that plays a fundamental role in modulating malignant cell behavior, understanding the influence of CAF on TCC will reveal new aspects of oral cancer biology and could identify novel biomarkers and/or therapeutic targets.

To address this, oral squamous cell carcinoma (OSCC; the most common form of oral cancer) spheroids will be established from OSCC-cell and CAF cocultures.

Tumour cells and fibroblasts will be labeled with fluorescent dyes (Blue and Green, respectively) and the interaction between these cells will be studied through flow cytometry and high content screening.

The identification and location of cell-in-cell structures will be performed on confocal microscopy, through immunostaining for pan-cytokeratins (epithelial phenotype cells), vimentin (mesenchymal phenotype cells) and p16INK4A (cell senescence), respectively.

Next, we will evaluate the effects of the interaction between OSCC and CAF on cancer cell behaviour and their gene expression, using RNAseq and Proteomics to identify key molecular pathways involved.

This will provide a platform to improve disease outcomes by developing novel therapeutic targets and prognostic biomarkers identified here in subsequent studies building on the collaboration fostered by this award.