Bay11-7082 inhibits the disintegration of the lymphendothelial barrier triggered by MCF-7 breast cancer spheroids; the role of ICAM-1 and adhesion

Abstract

Background:Many cancers spread through lymphatic routes, and mechanistic insights of tumour intravasation into the lymphatic vasculature and targets for intervention are limited. The major emphasis of research focuses currently on the molecular biology of tumour cells, while still little is known regarding the contribution of lymphatics.Methods:Breast cancer cell spheroids attached to lymphendothelial cell (LEC) monolayers were used to investigate the process of intravasation by measuring the areas of ‘circular chemorepellent-induced defects' (CCID), which can be considered as entry gates for bulky tumour intravasation. Aspects of tumour cell intravasation were furthermore studied by adhesion assay, and siRNA-mediated knockdown of intracellular adhesion molecule-1 (ICAM-1). Replacing cancer spheroids with the CCID-triggering compound 12(S)-hydroxyeicosatetraenoic acid (HETE) facilitated western blot analyses of Bay11-7082- and baicalein-treated LECs.Results:Binding of LECs to MCF-7 spheroids, which is a prerequisite for CCID formation, was mediated by ICAM-1 expression, and this depended on NF-κB and correlated with the expression of the prometastatic factor S100A4. Simultaneous inhibition of NF-κB with Bay11-7082 and of arachidonate lipoxygenase (ALOX)-15 with baicalein prevented CCID formation additively.Conclusion:Two mechanisms contribute to CCID formation: ALOX15 via the generation of 12(S)-HETE by MCF-7 cells, which induces directional migration of LECs, and ICAM-1 in LECs under control of NF-κB, which facilitates adhesion of MCF-7 cells to LECs.

Impact of cell lines included in enterovirus isolation protocol on perception of nonpolio enterovirus species C diversity

“…This demonstrates that MCF-7s sensitivity and bias for ECs is similar to that already described for HEp-2 (Arita et al, 2005;Rakoto-Andrianarivelo et al, 2007;Bessaud et al, 2012;Sadeuh-Mba et al, 2013). The expression of ICAM-1, the cell surface receptor for a good number of NPESC members (Newcombe et al, 2003), on MCF-7 is well documented (Komi and Lassila, 2000;Rosette et al, 2005;Viola et al, 2013). This might partly account for replication of the NPESC isolates on MCF-7 but not on RD cell line which lack ICAM-1 expression on the cell surface (Newcombe et al, 2003).…”

“…Despite this, the indigenous NPESC members recombining with OPV to make cVDPV2 in Nigeria are yet to be isolated and described. Therefore, in this study, including MCF-7 cell line, with documented expression of ICAM-1 (Komi and Lassila, 2000;Rosette et al, 2005;Viola et al, 2013), and another cell line, we analysed sewage samples from northern Nigeria for NPESC members. The results of this study confirm the circulation of NPESC members in northern Nigeria.…”

In vitro inhibition of breast cancer spheroid-induced lymphendothelial defects resembling intravasation into the lymphatic vasculature by acetohexamide, isoxsuprine, nifedipin and proadifen

“…Recent studies showed that the activity of NF- κ B (in addition to the activity of ALOX12/15 of MCF-7 cells) contributes to CCID formation (Vonach et al , 2011; Viola et al , 2012). Therefore, we assesed the effect of acetohexamide, isoxsuprine, nifedipin and proadifen on NF- κ B activity using a luciferase reporter fused to a NF- κ B-responsive promoter.…”

“…We simplified the three-dimensional co-culture cell model and replaced MCF-7 spheroids (as source of 12(S)-HETE stimulation) by direct 12(S)-HETE treatment, which allowed to perform western blot analyses. Interestingly, 12(S)-HETE transiently downregulated Erk1/2 phosphorylation (Vonach et al , 2011; Viola et al , 2012). Acetohexamide, isoxsuprine, nifedipin and proadifen inhibited one or more mobility markers (MLC2, MYPT and paxillin) in LECs (Figure 5A–D), thereby providing a molecular explanation for attenuated LEC migration.…”

“…In this model, the sizes of the cell-free areas (CCIDs) are measured that are formed in the endothelial monolayer directly underneath 12(S)-HETE-secreting tumour spheroids, which is a mechanistic cause for this phenomenon (Madlener et al , 2010; Kerjaschki et al , 2011; Vonach et al , 2011; Viola et al , 2012). MCF-7 spheroids were washed in PBS and transferred to cytotracker-stained LEC monolayers that were seeded into 24-well plates (Costar 3524; Sigma-Aldrich) in 2 ml EGM2 MV medium.…”