Immortalized Mouse Lymphatic Endothelial Cells-SV40

LEC–Cancer Cell Adhesion Induces Reciprocal Changes in Actin Reorganization

Cell adhesion in carcinogenesis is positively and negatively regulated, enabling cancer cells to attach to other cells and the extracellular matrix, favoring their permanence at the cancer stem cells (CSCs) niche or their migration and dissemination to distant sites. The actin cytoskeleton plays a critical role in cell adhesion and migration. Therefore, this study sought to identify the occurrence of changes in actin organization at sites of heterotypic cell–cell interaction between lymphatic endothelial cells (LECs) and the cancer cell lines.

For this purpose, we used the immortalized mouse LEC line and two mouse skin squamous carcinoma cell lines, PDV and HaCa4, both of which express the CSC marker SOX2. In individual cell cultures, LEC cells grew as compact adhesive cell monolayers, displaying a well-defined cortical actin network forming a honeycomb pattern with radial bundles of actin fibers at cell–cell contact sites. On the other hand, epithelial PDV and the epithelioid HaCa4 cells established cell–cell contacts with a polarized actin cytoskeleton organization.

Upon co-culture, we observed distinct morphological changes in both LECs and cancer cells. LEC cells exhibited a more elongated organization and no longer formed a close monolayer. Instead, they organized into an open network, establishing contact with cancer cells. The actin cytoskeleton of LEC and cancer cells appeared reorganized, and areas of directed actin membrane protrusions were evident at heterotypic cell adhesion sites, along with the presence of actin bundles and lamellipodia membrane protrusions. These results underscore the existence of productive adhesive interactions involving the actin cytoskeleton between LECs and cancer cells.