Viral Status and Microenvironment In Oropharyngeal Cancer: A Therapeutic Target

Objectives: 1.Determine whether there is a difference between microenvironmental interactions in HPV-positive and -negative oropharyngeal carcinoma.
2.Establish whether these differences influence tumour behaviour
3.Define the underlying secretome responsible for altering tumour behaviour
4.Establish whether targeted therapeutics can limit microenvironmental support for tumour invasion in vitro, as evidence for therapeutic potential in-vivo
Methods: Conditioned media was collected from HPV-positive and HPV-negative oropharyngeal carcinoma lines and used to stimulate normal fibroblasts. Further conditioned media was then collected from the stimulated fibroblasts, and used in migration/ proliferation experiments. A multitude of techniques were used to determine candidate molecules responsible for observed differences between HPV-positive and -negative cell line interactions. Clinically relevant inhibitors were then used to confirm whether interactions could be disrupted in-vitro and also to validate candidate molecules. Finally, a range of functional and analytical toxicity assays were undertaken to confirm that the efficacy of these inhibitors was attributable to receptor targeting.
Results: HPV-negative lines consistently demonstrated increased migration in response to stimulated fibroblast media, whereas HPV-positive lines did not. HGF and IL-6 were identified as key factors promoting cell migrations. Co-incubation of Foretenib or INCB28060 led to near-total abrogation of the additional migrations; all toxicity assays confirmed this effect was due to receptor targeting.
Conclusions: HPV-negative lines induced a characteristic stromal reaction that supported migration. HGF has a central role in the modelled interactions, although supplementation of intracellular STAT activity via IL-6 and/or constitutive STAT activation appears to have compounded HGF's effect; these additional derangements noted in HPV-negative cell lines may be the consequence of greater tumour evolution in HPV-negative disease. Clinically-relevant cMet inhibitors show promise in therapeutically targeting Oropharyngeal Carcinoma, and may be employed on the basis of Virus status in combination with biomarker analysis.