Featured Article: Downregulation of transgelin blocks interleukin-8 utilization and suppresses vasculogenic mimicry in breast cancer cells

Abstract

Vasculogenic mimicry (VM) is an angiogenic-independent mechanism of blood vessel formation whereby aggressive tumor cells undergo formation of capillarylike structures. Thus, interventions aimed at angiogenesis might not target the entire tumor vasculature. A more holistic approach is therefore needed in the development of improved antivascular agents.Transgelin, an actin-binding protein, has been associated with multiple stages of cancer development such as proliferation, migration and invasion, but little is known about its role in vasculogenic mimicry. We present here, an additional mechanism by which transgelin promotes malignancy by way of its association with the occurrence of VM. Although transgelin knockdown did not affect the transcript levels of most of the angiogenesis-related genes in this study, it was associated with the inhibition of the uptake of IL-8, accompanied by suppressed VM, indicating that transgelin is required for VM. These observations are relevant to the future development of efficient antivascular agents. AbstractVasculogenic mimicry (VM) is a non-classical mechanism recently described in many tumors, whereby cancer cells, rather than endothelial cells, form blood vessels. Transgelin is an actin-binding protein that has been implicated in multiple stages of cancer development. In this study, we investigated the role of transgelin in VM and assessed its effect on the expression of endothelial and angiogenesis-related genes during VM in MDA-MB-231 breast cancer cells. We confirmed the ability of MDA-MB-231 cells to undergo VM through a tube formation assay. Flow cytometry analysis revealed an increase in the expression of the endothelial-related markers VE-cadherin and CD34 in cells that underwent VM, compared with those growing in a monolayer, which was confirmed by immunocytochemistry. We employed siRNA to silence transgelin, and knockdown efficiency was determined by western blot analyses. Downregulation of transgelin suppressed cell proliferation and tube formation, but increased IL-8 levels in Matrigel cultures. RT-PCR analyses revealed that the expression of IL-8, VE-cadherin, and CD34 was unaffected by transgelin knockdown, indicating that increased IL-8 expression was not due to enhanced transcriptional activity. More importantly, the inhibition of IL-8/CXCR2 signaling also resulted in suppression of VM with increased IL-8 levels, confirming that increased IL-8 levels after transgelin knockdown was due to inhibition of IL-8 uptake. Our findings indicate that transgelin regulates VM by enhancing IL uptake. These observations are relevant to the future development of efficient antivascular agents.

Transgelin Silencing Induces Different Processes in Different Breast Cancer Cell Lines

“…The detection of TAGLN expression in BT 549 and PMC 42 cells is in agreement with its expression in TNBC tumors and other TNBC cell lines [ 16,33 ] and in the immortalized normal epithelial breast cell lines, MCF10A and MCF12A. [ 13 ] We confirmed the association of TAGLN with the actin cytoskeleton in both cell lines.…”

“…[ 17 ] It also impairs tube formation during vasculogenic mimicry in the TNBC cell line, MDA MB 231. [ 16 ] In contrast, restoration of TAGLN expression inhibits the migration of the colorectal cancer cell lines, DLD1, [ 10 ] and LoVo, [ 8 ] and the bladder carcinoma cell line, TSGH‐8301. [ 36 ] Decreases in migration after TAGLN restoration [ 37 ] as well as after TAGLN silencing, [ 18 ] have been described in different studies of SW480 colorectal cancer cells.…”

“…[ 15 ] Silencing of TAGLN expression leads to the suppression of cell proliferation and tube formation in MDA MB 231 cells. [ 16 ] Several studies have reported the role of TAGLN in the migration and invasion of cancer cells. However, TAGLN has both positive and negative roles in these processes, depending on the cell line.…”

Role of Matrix Metalloproteinases in Angiogenesis and Cancer

“…In the tumoral microenvironment, there is a complex and dynamically interacting areas involving stromal cells (fibroblasts, myofibroblasts, neuroendocrine cells and immune cells), blood vessels, lymphatic network, and ECM (157,158), resulting in a tremendous heterogeneity observed in cancer cells. This condition is because tumor cells express and modulate a broad group of signaling pathways including immune modulatory pathways of cytokines and chemokines, which participate in the progression and establishment of cancer cells (Tables 1, 2) (159)(160)(161)(162)(163)(164)(165)(166)(167)(168)(169). In this regard, both cytokines and chemokines induce the expression and activity of MMPs, which in turn allow for the activation of pro-inflammatory signaling pathways as well as the activating receptors, for example, expressed on the surface of T cells and NK cells.…”

Systematic identification of drug-based prognostic biomarkersby integrating multiomics in breast cancer

“…Wang [33] found that ACSL1 mRNA expression levels were significantly upregulated in clinical breast cancer tissues, and oncoprotein Hepatitis B virus X-interacting protein upregulated ACSL1 in breast cancer by activating transcription factor Sp1. The Aikins study [34] found that transgelin is an actin-binding protein associated with multiple stages of cancer development, such as proliferation, migration, and invasion. The authors studied the role of transgelin in vasculogenic mimicry (VM) and evaluated the effects of VM on endothelial cell-and angiogenesis related-gene expression in MDA-MB-231 breast cancer cells.…”