Abstract:Cancer cell metastasis is the main cause of death in patients with cancer. Many studies have investigated the biochemical factors that affect metastasis; however, the role of physical factors such as fluid shear stress (FSS) in tumorigenesis and metastasis have been less investigated. Triple-negative breast cancer (TNBC) has a higher incidence of lymph node invasion and distant metastasis than other subtypes of breast cancer. In this study, we investigated the influence of FSS in regulating the malignant behav… Show more
“…2A, D and E). The data are in agreement with previous reports of FAK requirement to promote cell migration in MDA-MB-231 and MDA-MB-468 in breast cancer cell lines (35), and with the effect of FAK autophosphorylation at Y397 in cell migration, invasion, and proliferation of gastric carcinomas (36). Figure 2Leptin-induced FAK activation occurs in a Src-dependent manner in MDA-MB-231 and MCF7 breast cancer cells.…”
Section: Resultssupporting
confidence: 92%
“…6D and E). These data is consistent with the contribution of FAK to the highly invasive phenotype of the triple-negative MDA-MB-231 and BT549 cancer cells (35, 45). Figure 7Leptin-induced secretion, activation of MMP-2 and MMP-9 and invasion in MDA-MB-231 cells is Src-dependent.…”
Breast cancer is the most common invasive neoplasia, and the second leading cause of the cancer deaths in women worldwide. Mammary tumorigenesis is severely linked to obesity, one potential connection is leptin. Leptin is a hormone secreted by adipocytes, which contributes to the progression of breast cancer. Cell migration, metalloproteases secretion, and invasion are cellular processes associated with various stages of metastasis. These processes are regulated by the kinases FAK and Src. In this study, we utilized the breast cancer cell lines MCF7 and MDA-MB-231 to determine the effect of leptin on FAK and Src kinases activation, cell migration, metalloprotease secretion, and invasion. We found that leptin activates FAK and Src and induces the localization of FAK to the focal adhesions. Interestingly, leptin promotes the activation of FAK through a Src- and STAT3-dependent canonical pathway. Specific inhibitors of FAK, Src and STAT3 showed that the effect exerted by leptin in cell migration in breast cancer cells is dependent on these proteins. Moreover, we established that leptin promotes the secretion of the extracellular matrix remodelers, MMP-2 and MMP-9 and invasion in a FAK and Src-dependent manner. Our findings strongly suggest that leptin promotes the development of a more aggressive invasive phenotype in mammary cancer cells.
“…2A, D and E). The data are in agreement with previous reports of FAK requirement to promote cell migration in MDA-MB-231 and MDA-MB-468 in breast cancer cell lines (35), and with the effect of FAK autophosphorylation at Y397 in cell migration, invasion, and proliferation of gastric carcinomas (36). Figure 2Leptin-induced FAK activation occurs in a Src-dependent manner in MDA-MB-231 and MCF7 breast cancer cells.…”
Section: Resultssupporting
confidence: 92%
“…6D and E). These data is consistent with the contribution of FAK to the highly invasive phenotype of the triple-negative MDA-MB-231 and BT549 cancer cells (35, 45). Figure 7Leptin-induced secretion, activation of MMP-2 and MMP-9 and invasion in MDA-MB-231 cells is Src-dependent.…”
Breast cancer is the most common invasive neoplasia, and the second leading cause of the cancer deaths in women worldwide. Mammary tumorigenesis is severely linked to obesity, one potential connection is leptin. Leptin is a hormone secreted by adipocytes, which contributes to the progression of breast cancer. Cell migration, metalloproteases secretion, and invasion are cellular processes associated with various stages of metastasis. These processes are regulated by the kinases FAK and Src. In this study, we utilized the breast cancer cell lines MCF7 and MDA-MB-231 to determine the effect of leptin on FAK and Src kinases activation, cell migration, metalloprotease secretion, and invasion. We found that leptin activates FAK and Src and induces the localization of FAK to the focal adhesions. Interestingly, leptin promotes the activation of FAK through a Src- and STAT3-dependent canonical pathway. Specific inhibitors of FAK, Src and STAT3 showed that the effect exerted by leptin in cell migration in breast cancer cells is dependent on these proteins. Moreover, we established that leptin promotes the secretion of the extracellular matrix remodelers, MMP-2 and MMP-9 and invasion in a FAK and Src-dependent manner. Our findings strongly suggest that leptin promotes the development of a more aggressive invasive phenotype in mammary cancer cells.
“…We observed differential expression of genes in these pathways and network analysis revealed key interactions that possibly contribute in EMT promotion and increased adhesiveness to endothelial cells during metastatic progression. These ndings support previous studies that reported modulation of cell signalling pathways involved in tumor metastasis in response to uid shear stress exposure in other cell types 25,56,59,66,67 . However, the signalling pathways and molecular mechanisms through which uid ow promotes EMT and adhesion of breast cancer cells to endothelial cells remain elusive and was not the focus of studies presented herein.…”
Section: Discussionsupporting
confidence: 91%
“…representing the most clinically aggressive subtype of breast cancer. This particular subtype is highly studied due to its unique biology, overall poor prognosis, early pattern for metastases and relative lack of therapeutic targets compared to the other subtypes 50,55,56 . Previous in vitro studies in which cancer cells were exposed to uid shear stresses in the range of those encountered in the tumor microenvironment have demonstrated promotion or induction of EMT 12,14,25,57,58,59,60 .…”
Background: Fluid forces are an integral part of the tumor microenvironment through all phases of development and progression. However, it is not well understood how these forces affect key steps in the progression of breast cancer of Epithelial-to-Mesenchymal Transition (EMT) and adhesion to vascular wall endothelial cells. EMT is associated with the progression of most carcinomas through induction of new transcriptional programs within affected epithelial cells, resulting in cells becoming more motile and adhesive to endothelial cells.Methods: MDA-MB-231, SK-BR-3, BT-474, and MCF-7 cells and normal Human Mammary Epithelial Cells (HMECs) were exposed to fluid flow in a parallel-plate bioreactor system. Changes in gene expression were quantified using microarrays and qPCR, gene-gene interactions were elucidated using network analysis, and key modified genes were examined in clinical datasets. Changes in protein expression of key EMT markers between chemically induced EMT and flow-exposed cells were compared in immunocytochemistry assays. Finally, the ability of flow-stimulated and unstimulated cancer cells to adhere to an endothelial monolayer was evaluated in flow and static adhesion experiments.Results: Fluid flow stimulation resulted in upregulation of EMT inducers and downregulation of repressors. Specifically, Vimentin and Snail were upregulated both at the gene and protein expression levels in flow stimulated HMECs, suggesting progression towards an EMT phenotype. Flow-induced overexpression of a panel of cell adhesion genes was also observed. Network analysis revealed genes involved in cell flow responses including FN1, PLAU, and ALCAM. When evaluated in clinical datasets, overexpression of FN1, PLAU, and ALCAM was observed in patients with most subtypes of breast cancer. We also observed increased adhesion of flow-stimulated breast cancer cells compared to unstimulated controls, suggesting an increased potential to form secondary tumors at metastatic sites. Conclusions: This study shows that prolonged fluid force exposure on the order of 1 Pa promotes EMT and adhesion of breast cancer cells to an endothelial monolayer. Further, identified biomarkers were distinctly expressed in patient populations. A better understanding of how biophysical forces such as shear stress affect cellular processes involved in metastatic progression of breast cancer is important for identifying new molecular markers for disease progression, and for predicting metastatic risk.
“…Further, we show that this effect is more pronounced in the basal MDA-MB-231 cells, representing the most clinically aggressive subtype of breast cancer. This subtype is highly studied due to its unique biology, overall poor prognosis, early pattern for metastases and relative lack of therapeutic targets compared to the other subtypes (51,(58)(59)(60). Previous in vitro studies in which cancer cells were exposed to uid shear stresses in the range of those encountered in the tumor microenvironment have demonstrated promotion or induction of EMT (12,24,(61)(62)(63).…”
Background: Mechanical interactions between tumor cells and microenvironments are frequent phenomena during breast cancer progression, however, it is not well understood how interactions in the magnitude of those encountered in the vascular microenvironment affect expression of genes related to Epithelial-to-Mesenchymal Transition (EMT) and adhesion to endothelial cells. EMT is associated with the progression of most carcinomas through induction of new transcriptional programs within affected epithelial cells, resulting in cells becoming more motile and adhesive to endothelial cells. Methods: MDA-MB-231, SK-BR-3, BT-474, and MCF-7 cells and normal Human Mammary Epithelial Cells (HMECs) were exposed to fluid flow in a parallel-plate bioreactor system. Changes in gene expression were quantified using microarrays and qPCR, gene-gene interactions were elucidated using network analysis, and key modified genes were examined in clinical datasets. Changes in protein expression of key EMT markers between chemically induced EMT and flow-exposed cells were compared in immunocytochemistry assays. Finally, the ability of flow-stimulated and unstimulated cancer cells to adhere to an endothelial monolayer was evaluated in flow and static adhesion experiments. Results: Fluid flow stimulation resulted in upregulation of EMT inducers and downregulation of repressors. Specifically, Vimentin and Snail were upregulated both at the gene and protein expression levels in flow stimulated HMECs, suggesting progression towards an EMT phenotype. Flow-induced overexpression of a panel of cell adhesion genes was also observed. Network analysis revealed genes involved in cell flow responses including FN1, PLAU, and ALCAM. When evaluated in clinical datasets, overexpression of FN1, PLAU, and ALCAM was observed in patients with most subtypes of breast cancer. We also observed increased adhesion of flow-stimulated breast cancer cells compared to unstimulated controls, suggesting an increased potential to form secondary tumors at metastatic sites. Conclusions: This study shows that fluid forces on the order of 1 Pa promote EMT and adhesion of breast cancer cells to an endothelial monolayer and identified biomarkers were distinctly expressed in patient populations. A better understanding of how biophysical forces such as shear stress affect cellular processes involved in metastatic progression of breast cancer is important for identifying new molecular markers for disease progression, and for predicting metastatic risk.
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