Tenascin-C increases lung metastasis by impacting blood vessel invasions

Zhen Sun,Thomas Hussenet,Devadarssen Murdamoothoo,Gerhard Christofori,Renate Kain,Catherine Bourdon,Inés Velázquez-Quesada,Gertraud Orend,Carole Mathelin,Michael Van Der Heyden,William Erne,Claire Deligne,Caroline Spenlé,Constance Ahowesso,Felicitas Oberndorfer,Thomas Loustau,P Mangin ,Olivier Lefèbvre ,Gerlinde Avérous ,Kim S Midwood ,Marie–Pierre Chenard ,Alev Yılmaz ,Cherine Abou-Fayçal ,André Oszwald ,Albrecht Klein

doi:10.1016/j.matbio.2019.07.001

Abstract

Metastasis is a major cause of death in cancer patients. The extracellular matrix molecule tenascin-C is a known promoter of metastasis, however the underlying mechanisms are not well understood. To further analyze the impact of tenascin-C on cancer progression we generated MMTV-NeuNT mice that develop spontaneous mammary tumors, on a tenascin-C knockout background. We also developed a syngeneic orthotopic model in which tumor cells derived from a MMTV-NeuNT tumor. Tumor cells were transfected with control shRNA or with shRNA to knockdown tenascin-C expression and, were grafted into the mammary gland of immune competent, wildtype or tenascin-C knockout mice. We show that stromal-derived tenascin-C increases metastasis by reducing apoptosis and inducing the cellular plasticity of cancer cells located in pulmonary blood vessels invasions (BVI), before extravasation. We characterized BVI as organized structures of tightly packed aggregates of proliferating tumor cells with epithelial characteristics, surrounded by Fsp1+ cells, internally located platelets and, a luminal monolayer of endothelial cells. We found extracellular matrix, in particular, tenascin-C, between the stromal cells and the tumor cell cluster. In mice lacking stromal-derived tenascin-C, the organization of pulmonary BVI was significantly affected, revealing novel functions of host-derived tenascin-C in supporting the integrity of the endothelial cell coat, increasing platelet abundance, tumor cell survival, epithelial plasticity, thereby promoting overall lung metastasis. Many effects of tenascin-C observed in BVI including enhancement of cellular plasticity, survival and migration, could be explained by activation of TGF-β signaling. Finally, in several human cancers, we also observed BVI to be surrounded by an endothelial monolayer and to express tenascin-C. Expression of tenascin-C is specific to BVI and is not observed in lymphatic vascular invasions frequent in breast cancer, which lack an endothelial lining. Given that BVI have prognostic significance for many tumor types, such as shorter cancer patient survival, increased metastasis, vessel occlusion, and organ failure, our data revealing a novel mechanism by which stromal tenascin-C promotes metastasis in human cancer, may have potential for diagnosis and therapy.

Highlights

Despite earlier diagnosis and improved treatment a high number of cancer patients die due to cancerrelated complications, tumor recurrence and, most frequently, metastasis [1]
Tumor cells disseminate from the primary tumor and invade blood or lymphatic vessels where they can be found as circulating tumor cells appearing in a variety of forms as ranging from single cells or small cell clusters up to multicellular tumor cell aggregates or tumor emboli
Tumor emboli can be classified as blood vessel invasions (BVI) or lymphatic vessel invasions (LVI), all together covered by the term lympho-vascular invasions [2e4]

Summary

Introduction

Despite earlier diagnosis and improved treatment a high number of cancer patients die due to cancerrelated complications, tumor recurrence and, most frequently, metastasis [1]. Tumor cells disseminate from the primary tumor and invade blood or lymphatic vessels where they can be found as circulating tumor cells appearing in a variety of forms as ranging from single cells or small cell clusters up to multicellular tumor cell aggregates or tumor emboli. Tumor emboli can be classified as blood vessel invasions (BVI) or lymphatic vessel invasions (LVI), all together covered by the term lympho-vascular invasions [2e4]. The presence of vascular invasions in the primary tumor and the distant organ correlates with poorer cancer patient survival, increased metastasis, vessel occlusion and organ failure [5,6]. Very little is known about the cellular composition of vascular invasions, nor whether there are differences in BVI in comparison to LVI

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Conclusion