The Influence of VE-Cadherin on Adhesion and Incorporation of Breast Cancer Cells into Vascular Endothelium

Identification of Neural (N)-Cadherin as a Novel Endothelial Cell Receptor for Fibrin and Localization of the Complementary Binding Sites

Based on the high structural homology between vascular endothelial (VE)-cadherin and neural (N)-cadherin, we hypothesized that fibrin, which is known to interact with VE-cadherin and promote angiogenesis through this interaction, may also interact with N-cadherin. To test this hypothesis, we prepared fibrin and its plasmin-produced and recombinant fragments covering practically all parts of the fibrin molecule. We also prepared the soluble extracellular portion of N-cadherin (sN-cadherin), which includes all five extracellular N-cadherin domains, and studied its interaction with fibrinogen, fibrin, and the aforementioned fibrin fragments using two independent methods, ELISA and SPR. The experiments confirmed our hypothesis, revealing that fibrin interacts with sN-cadherin with high affinity. Furthermore, the experiments localized the N-cadherin binding site within the fibrin βN-domains. Notably, the recombinant dimeric (β15-66)2 fragment, corresponding to these domains and mimicking their dimeric arrangement in fibrin, preserved the N-cadherin-binding properties of fibrin. To localize the fibrin binding site within N-cadherin, we performed ELISA and SPR experiments with (β15-66)2 and recombinant N-cadherin fragments representing its individual extracellular domains and combinations thereof. The results obtained indicate that the interaction of fibrin with N-cadherin occurs through the third and fifth extracellular domains of the latter. This is in contrast to our previous study, which revealed that fibrin interacts only with the third extracellular domain of VE-cadherin. In conclusion, our study identified N-cadherin as a novel receptor for fibrin and localized complementary binding sites within both fibrin and N-cadherin. The pathophysiological role of this interaction remains to be established.

Unravelling heterogeneous effects of cancer‑associated fibroblasts on poor prognosis markers in breast cancer EM‑G3 cell line: In vitro‑targeted treatment (anti‑IL-6, anti‑VEGF-A, anti‑MFGE8) based on transcriptomic profiling

Breast cancer is the most frequently diagnosed cancer in women worldwide. Although dramatically increased survival rates of early diagnosed cases have been observed, late diagnosed patients and metastatic cancer may still be considered fatal. The present study's main focus was on cancer‑associated fibroblasts (CAFs) which is an active component of the tumor microenvironment (TME) regulating the breast cancer ecosystem. Transcriptomic profiling and analysis of CAFs isolated from breast cancer skin metastasis, cutaneous basal cell carcinoma, and squamous cell carcinoma unravelled major gene candidates such as IL6, VEGFA and MFGE8 that induced co‑expression of keratins‑8/‑14 in the EM‑G3 cell line derived from infiltrating ductal breast carcinoma. Western blot analysis of selected keratins (keratin‑8, ‑14, ‑18, ‑19) and epithelial‑mesenchymal transition‑associated markers (SLUG, SNAIL, ZEB1, E‑/N‑cadherin, vimentin) revealed specific responses pointing to certain heterogeneity of the studied CAF populations. Experimental in vitro treatment using neutralizing antibodies against IL-6, VEGF‑A and MFGE8 attenuated the modulatory effect of CAFs on EM‑G3 cells. The present study provided novel data in characterizing and understanding the interactions between CAFs and EM‑G3 cells in vitro. CAFs of different origins support the pro‑inflammatory microenvironment and influence the biology of breast cancer cells. This observation potentially holds significant interest for the development of novel, clinically relevant approaches targeting the TME in breast cancer. Furthermore, its implications extend beyond breast cancer and have the potential to impact a wide range of other cancer types.

Adhesion to the Brain Endothelium Selects Breast Cancer Cells with Brain Metastasis Potential

Tumor cells metastasize from a primary lesion to distant organs mainly through hematogenous dissemination, in which tumor cell re-adhesion to the endothelium is essential before extravasating into the target site. We thus hypothesize that tumor cells with the ability to adhere to the endothelium of a specific organ exhibit enhanced metastatic tropism to this target organ. This study tested this hypothesis and developed an in vitro model to mimic the adhesion between tumor cells and brain endothelium under fluid shear stress, which selected a subpopulation of tumor cells with enhanced adhesion strength. The selected cells up-regulated the genes related to brain metastasis and exhibited an enhanced ability to transmigrate through the blood-brain barrier. In the soft microenvironments that mimicked brain tissue, these cells had elevated adhesion and survival ability. Further, tumor cells selected by brain endothelium adhesion expressed higher levels of MUC1, VCAM1, and VLA-4, which were relevant to breast cancer brain metastasis. In summary, this study provides the first piece of evidence to support that the adhesion of circulating tumor cells to the brain endothelium selects the cells with enhanced brain metastasis potential.

Protein Profiling of Breast Carcinomas Reveals Expression of Immune-Suppressive Factors and Signatures Relevant for Patient Outcome

In cancer, the complex interplay between tumor cells and the tumor microenvironment results in the modulation of signaling processes. By assessing the expression of a multitude of proteins and protein variants in cancer tissue, wide-ranging information on signaling pathway activation and the status of the immunological landscape is obtainable and may provide viable information on the treatment response. Archived breast cancer tissues from a cohort of 84 patients (no adjuvant therapy) were analyzed by high-throughput Western blotting, and the expression of 150 proteins covering central cancer pathways and immune cell markers was examined. By assessing CD8α, CD11c, CD16 and CD68 expression, immune cell infiltration was determined and revealed a strong correlation between event-free patient survival and the infiltration of immune cells. The presence of tumor-infiltrating lymphocytes was linked to the pronounced activation of the Jak/Stat signaling pathway and apoptotic processes. The elevated phosphorylation of PPARγ (pS112) in non-immune-infiltrated tumors suggests a novel immune evasion mechanism in breast cancer characterized by increased PPARγ phosphorylation. Multiplexed immune cell marker assessment and the protein profiling of tumor tissue provide functional signaling data facilitating breast cancer patient stratification.

Mechanisms of Cell Adhesion Molecules in Endocrine-Related Cancers: A Concise Outlook

Chemotherapy is a critical treatment for endocrine-related cancers; however, chemoresistance and disease recurrence remain a challenge. The interplay between cancer cells and the tumor microenvironment via cell adhesion molecules (CAMs) promotes drug resistance, known as cell adhesion-mediated drug resistance (CAM-DR). CAMs are cell surface molecules that facilitate cell-to-cell or cell-to-extracellular matrix binding. CAMs exert an adhesion effect and trigger intracellular signaling that regulates cancer cell stemness maintenance, survival, proliferation, metastasis, epithelial-mesenchymal transition, and drug resistance. To understand these mechanisms, this review focuses on the role of CD44, cadherins, selectins, and integrins in CAM-DR in endocrine-related cancers.

Comparative study of the effects of cigarette smoke versus next generation tobacco and nicotine product extracts on endothelial function

Tobacco smoking and hemodynamic forces are key stimuli for the development of endothelial dysfunction. As an alternative to smoking, next generation tobacco and nicotine products (NGP) are now widely used. However, little is known about their potential pro-inflammatory and atherogenic effects on the endothelium. In this study, we analyzed key parameters of endothelial function after exposure to aqueous smoke extracts (AqE) of a heated tobacco product (HTP), an electronic cigarette (e-cig), a conventional cigarette (3R4F) and pure nicotine. All experiments were performed under atheroprotective high laminar or atherogenic low flow with primary human endothelial cells. Treatment with 3R4F, but not alternative smoking products, reduced endothelial cell viability and wound healing capability via the PI3K/AKT/eNOS(NOS3) pathway. Laminar flow delayed detrimental effects on cell viability by 3R4F treatment. 3R4F stimulation led to activation of NRF2 antioxidant defense system at nicotine concentrations ≥0.56 μg/ml and increased expression of its target genes HMOX1 and NQO1. Treatment with HTP revealed an induction of HMOX1 and NQO1 at dosages with ≥1.68 μg/ml nicotine, whereas e-cig and nicotine exposure had no impact. Analyses of pro-inflammatory genes revealed an increased ICAM1 expression under 3R4F treatment. 3R4F reduced VCAM1 expression in a dose-dependent manner; HTP treatment had similar but milder effects; e-cig and nicotine treatment had no impact. SELE expression was induced by 3R4F under static conditions. High laminar flow prevented this upregulation. Stimulation with laminar flow led to downregulation of CCL2 (MCP-1). From this downregulated level, only 3R4F increased CCL2 expression at higher concentrations. Finally, under static conditions, all components increased adhesion of monocytes to endothelial cells. Interestingly, only stimulation with 3R4F revealed increased monocyte adhesion under atherosclerosis-prone low flow. In conclusion, all product categories activated anti-oxidative or pro-inflammatory patterns. NGP responses were typically lower than in 3R4F exposed cells. Also, 3R4F stimulation led to an impaired endothelial wound healing and induced a pro-inflammatory phenotype compared to NGP treatment.