Tumour cell CD99 regulates transendothelial migration via CDC42 and actin remodelling

Abstract

Metastasis requires tumour cells to cross endothelial cell (EC) barriers using pathways similar to those used by leucocytes during inflammation. Cell surface CD99 is expressed by healthy leucocytes and EC and participates in inflammatory transendothelial migration (TEM). Tumour cells also express CD99 and we have analysed its role in tumour progression and cancer cell TEM. Tumour cell CD99 was required for adhesion to ECs, but inhibited invasion of the endothelial barrier and migratory activity. Furthermore, CD99 depletion in tumour cells caused redistribution of the actin cytoskeleton and increased activity of the Rho GTPase CDC42, known for its role in actin remodelling and cell migration. In a xenograft model of breast cancer, tumour cell CD99 expression inhibited metastatic progression and patient samples showed reduced expression of the CD99 gene in brain metastases compared to matched primary breast tumours. We conclude that CD99 negatively regulates CDC42 and cell migration. However, CD99 has both pro- and anti-tumour activity and our data suggests that this results in part from its functional linkage to CDC42 and the diverse signalling pathways downstream of this Rho GTPase.

Pro- and anti-tumour activities of CD146/MCAM in breast cancer result from its heterogeneous expression and association with epithelial to mesenchymal transition

“…MDA-MB-231 and BrM cells (2 x10 5 /ml) were CTG labelled as described in (32), before seeding to confluent EC monolayers in 1:1 ECMB:RPMI media. MDA-MB-231 and BrM cell migration was halted at 18 h by fixing in 4% PFA for 10 min followed by washing twice in 1x PBS (250µl for upper chamber and 500µl for lower chamber).…”

“…Cancer cell spreading and intercalation into endothelial monolayers is indicative of cancer cell transmigration (32)(33)(34). Intercalation was determined by live cell imaging as previously described (32,35).…”

“…Cancer cell spreading and intercalation into endothelial monolayers is indicative of cancer cell transmigration (32)(33)(34). Intercalation was determined by live cell imaging as previously described (32,35). Briefly, endothelial cells were seeded to 96 well plates at a density of 1x10 4 /well in 100μl to achieve confluent monolayers in 24-48 h. Once confluent endothelial monolayers were established, CTG labelled cancer cells (as described in adhesion assay) were seeded onto endothelial monolayers at a density of 1x10 4 per well in 50μl of media (total media volume 150μl including endothelial culture medium).…”

“…Images were taken every 5 min for 4 h using 20x objective. Images were analysed as previously described (32).…”

Fucoxanthin prevents breast cancer metastasis by interrupting circulating tumor cells adhesion and transendothelial migration

“…Cell adhesion molecules (CAMs) expressed on the surface of endothelial cells play a critical role in attracting CTCs to adhere to the vascular endothelium, and the expression of CAMs including VCAM-1, ICAM-1, and E-selectin is regulated by inflammatory factor-induced NF-lB signaling pathway (Hoesel and Schmid, 2013;Lu et al, 2014;Lian et al, 2016;Lu et al, 2019a). Transendothelial migration of CTCs is similar to the pathway used by leukocytes during inflammation (Reymond et al, 2013;Mannion et al, 2021). Regulatory molecules involved in the transendothelial migration of leukocytes and cancer cells could serve as potential targets for pharmaceutical compound screening (Salminen et al, 2020).…”