Extracellular Vesicles as Carriers of CD147 in Thyroid Tumor Microenvironment.

Rio de Janeiro

Congreso; XVI Latin American Thyroid Congress; 2017

Latin American Thyroid Society

Introduction: The influence of tumor-stromal crosstalk on tumor progression is recognized in different types of cancer. Tumor-secretedextracellular vesicles (EVs) act as intercellular messengers between tumor and stromal cells in local and distantmicroenvironments. The mechanisms by which tumor cells establish a permissive microenvironment that promotes thyroidcancer progression remain largely undefined. CD147 is a transmembrane glycoprotein that induces matrix metalloproteinases(MMPs) expression. CD147 level correlates with the dedifferentiation-degree of thyroid cancer and has also been suggested asa significant prognostic factor in differentiated thyroid carcinomas. In preliminary studies, we found that thyroid tumor cell-fibroblasts(Fb) interaction promotes the secretion and activation of MMPs and tumor cell migration. Objectives: To identifyEVs production and their CD147 expression as potential features of thyroid tumor malignant progression in a model of tumor-stromacell interaction. Methods: As an in vitro tumor-stroma cell interaction model, non-tumor cells (N-ThyOri), thyroidpapillary carcinoma cells (TPC-1) and thyroid anaplastic cells (8505c) were co-cultured with normal Fb. EVs were isolatedfrom conditioned media (CMs) by differential centrifugation and filtration steps. EVs ultrastructural features, and EVs sizesand populations in co-cultured and isolated cells were characterized by Transmission Electronic Microscopy (TEM) and DynamicLight Scattering. CD147 expression was analyzed by western blotting and immunogold labeling in EVs, and by indirectimmunofluorescence in whole cells. Results: Cell membrane periphery of thyroid cell-Fb co-cultures was rich in both roundand villi-like membrane projections. In contrast, TEM analysis of normal Fb or isolated thyroid cells revealed a smoother cellsurface. Isolated EVs from CMs ranged between 50-600 nm. The CD147 protein in EVs from CMs evidenced a higher expressionin TPC-1-Fb and 8505c-Fb co-cultures when compared to N-ThyOri-Fb co-cultures. By immunofluorescence, CD147expression in whole tumor thyroid cells displayed a dotted pattern during thyroid tumor cell-Fb co-culture. Conclusion: Theresults suggest that CD147 could play an active role in intercellular communication events in thyroid-tumor microenvironment,stimulating the release of MMPs by cells in this environment and the consequent migration and cellular invasion.