Influence of Exogenous Tissue Factor on Estrogen Receptorα Expression in Breast Cancer Cells: Involvement of β1-Integrin, PAR2, and Mitogen-Activated Protein Kinase Activation

Abstract

Increased expression of tissue factor (TF) has been associated with invasive forms of breast cancer. Conversely, the loss of estrogen receptor A (ERA) is associated with increased cell invasiveness. We have examined the influence of exogenous truncated recombinant TF (rTF) on ERA expression and cell invasiveness and investigated the mechanism of rTF signaling. The influence of rTF on ERA expression in MCF-7 and T47D cell lines was investigated using reverse transcription-PCR and ELISA. Cell invasion was measured using Boyden chamber-based invasion assays. Additionally, the interaction of fluorescein-labeled rTF with the surface of MCF-7 cells and particularly with B 1 -integrin was examined. Treatment of cells with rTF resulted in the downregulation of ERA mRNA and protein over 24 h, which required B 1 -integrin and involved the mitogen-activated protein kinase pathway but did not require PAR2 activation. The addition of rTF reduced estradiol-mediated cell proliferation as well as increased cell invasiveness requiring both PAR2 and B 1 -integrin activation. Fluorescein-labeled rTF was shown to bind to the surface of MCF-7 cells within 5 min and peaked at 15 min. The bound rTF colocalized with cellular B 1 -integrin and was disrupted in the presence of excess unlabeled rTF and an anti-B 1 polyclonal antibody. Finally, affinity purification of B 1 -integrin using rTF-conjugated agarose showed a requirement for the presence of divalent cations but not factor VIIa. The results indicate that rTF is capable of down-regulating ERA expression in breast cancer cells, resulting in decreases in estrogen-mediated cell proliferation and increased invasiveness. Furthermore, the mechanisms by which rTF induces these changes involve both PAR2 and B 1 -integrin.

Regulation of Alveolar Procoagulant Activity and Permeability in Direct Acute Lung Injury by Lung Epithelial Tissue Factor

“…The disruption of alveolar epithelial cell attachments to the basement membrane seen in microscopy of TF ΔLEpi mice raises the possibility that additional noncoagulant mechanisms are involved in permeability maintenance. For example, TF is known to interact with b1-integrin and actin during cancer metastasis (47,48). Whether TF interacts with b1-integrin or other cytoskeletal structures in lung epithelial cells is unknown, and is the focus of ongoing studies.…”

Induction of Endothelial Cell Proliferation by Recombinant and Microparticle-Tissue Factor Involves β1-Integrin and Extracellular Signal Regulated Kinase Activation

“…11 We have previously demonstrated the interaction of lipidated recombinant TF with the ␤1-integrin subunit and shown that this was independent of FVIIa. 10 However, the mechanism by which TF interacts with integrins remains unclear.…”

Breast cancer phenotypes regulated by tissue factor-factor VII pathway: Possible therapeutic targets

“…Exogenously synthesized TF in patients may affect a number of breast cancer cell characteristics. It was revealed that a paracrine effect of TF can influence the growth and metastasis of breast cancer cells [79] . Treatment of cells with recombinant TF, mimicking stromal-derived TF (Figure 3), enhances the invasive and proliferative properties of these cells.…”

“…Treatment of cells with recombinant TF, mimicking stromal-derived TF (Figure 3), enhances the invasive and proliferative properties of these cells. This occurs via activation of β1-integrins and/or PAR2-dependent signals, followed by inactivation of transcription of the estrogen receptor (ER) gene [79] (Figure 3). The involvement of integrins in TF-driven phenotype expressions of breast cancer cells is similar to the findings that association of TF integrated into plasma membrane of keratinocytes and breast cancer cells bind integrins and may support growth of breast tumor [30] .…”