IADR Abstract Archives
Tumour-stromal Crosstalk in Metastatic Lymph Nodes of Oral Cancer.
Objectives: Oral Squamous Cell Carcinoma (OSCC) is a significant cause of morbidity and mortality worldwide. The prognosis for patients with metastatic tumour invasion out of neck lymph nodes, termed extracapsular spread (ECS), is particularly poor. Cells of the tumour microenvironment, including myofibroblasts and endothelial cells, promote primary tumour development, including epithelial-mesenchymal transition (EMT). However, their contribution to ECS development is largely unexplored.
This work aims to determine the abundance of these stromal cell types in ECS positive and negative lymph nodes and examine this mechanistically in in vitro co-culture models.
Methods: ECS-positive (n=22) and negative (n=22) paired tumour specimens were examined for EMT markers (Slug, Snail, Twist, ZEB1), lymphatic (D2-40) and vascular (CD34) endothelial cells and myofibroblasts (αSMA) using immunohistochemistry. Oral cancer cell lines (OCCLs) derived from OSCC and lymph node metastases were incubated with conditioned media (CM) from oral fibroblasts, myofibroblasts and cancer-associated fibroblasts (CAFs). The expression of EMT markers by OCCLs was analysed using western blotting and qRT-PCR. The effect of OCCL CM on endothelial cell tubule formation in Matrigel was also examined.
Results: Vascular density and αSMA expression were significantly elevated, and Snail and Slug were significantly depleted, in ECS+ nodes compared to ECS- (p<0.05). However, lymphovascular density, Twist and ZEB1 did not differ between ECS+ and ECS- groups.
Myofibroblast (experimentally-derived CAF) and primary CAF-derived CM had limited effect on EMT marker expression in OCCLs. Lymph node metastases-derived OCCLs BICR22 and TR146 showed a significant increase in ZEB1 and Slug mRNA expression, respectively, in response to myofibroblast CM (P<0.05).
OCCL CM increased tubule formation in lymphatic and vascular endothelial cells, reaching significance only for primary tumour-derived OCCLs (p<0.05).
Conclusions: This novel work indicates fibroblasts and endothelial cells may play a role in the development of ECS. With further work this could lead to novel treatment strategies for patients with advanced OSCC.
This work aims to determine the abundance of these stromal cell types in ECS positive and negative lymph nodes and examine this mechanistically in in vitro co-culture models.
Methods: ECS-positive (n=22) and negative (n=22) paired tumour specimens were examined for EMT markers (Slug, Snail, Twist, ZEB1), lymphatic (D2-40) and vascular (CD34) endothelial cells and myofibroblasts (αSMA) using immunohistochemistry. Oral cancer cell lines (OCCLs) derived from OSCC and lymph node metastases were incubated with conditioned media (CM) from oral fibroblasts, myofibroblasts and cancer-associated fibroblasts (CAFs). The expression of EMT markers by OCCLs was analysed using western blotting and qRT-PCR. The effect of OCCL CM on endothelial cell tubule formation in Matrigel was also examined.
Results: Vascular density and αSMA expression were significantly elevated, and Snail and Slug were significantly depleted, in ECS+ nodes compared to ECS- (p<0.05). However, lymphovascular density, Twist and ZEB1 did not differ between ECS+ and ECS- groups.
Myofibroblast (experimentally-derived CAF) and primary CAF-derived CM had limited effect on EMT marker expression in OCCLs. Lymph node metastases-derived OCCLs BICR22 and TR146 showed a significant increase in ZEB1 and Slug mRNA expression, respectively, in response to myofibroblast CM (P<0.05).
OCCL CM increased tubule formation in lymphatic and vascular endothelial cells, reaching significance only for primary tumour-derived OCCLs (p<0.05).
Conclusions: This novel work indicates fibroblasts and endothelial cells may play a role in the development of ECS. With further work this could lead to novel treatment strategies for patients with advanced OSCC.