Bioengineering of a tumour-stroma 3D-tumouroid co-culture model of hypopharyngeal cancer.

Head and neck cancer (HNC) differs at anatomical sites and hypopharyngeal cancer (HPC) is a type of HNC. The non-surgical treatment option for advanced cases of HPC is radiotherapy (RT) with or without chemotherapy but survival is poor. Thus, new treatment approaches in combination with RT are essential. Yet, obtaining post-RT treated tumour specimens and lack of animal models with identical anatomical sites are the major translational research barriers. To overcome these barriers, for the first time, we have developed a tumour-stroma based in vitro three-dimensional (3D)-tumouroid co-culture model of HPC by growing FaDu and HS-5 cells together to mimic the complex tumour-microenvironment in a Petri dish. Before growing the cells together, imaging flow cytometry revealed distinct epithelial and non-epithelial characteristics of the cells. Growth rate of the 3D-tumouroid co-culture was significantly higher compared to the tumouroid monoculture of FaDu. Histology and morphometric analysis were done for the characterisation as well as the development of hypoxia was measured by CAIX immunostaining in this 3D-tumouroid co-culture. Taken together, this innovative in vitro 3D model of HPC resembles many features of the original tumour. The wider application of this pre-clinical research tool is in understanding newer combination (e.g. immunotherapy) treatment approaches with RT in HPC and beyond.