Shear stress induces internalization of E-cadherin and invasiveness in metastatic oesophageal cancer cells by a Src-dependent pathway.
Metastatic disease is dependent on tumor cell migration through the venous and lymphatic systems and requires dynamic rearrangement of adherens junctions. Endocytosis of cadherins is a key mechanism to dynamically arrange adherens junctions, signaling, and motility in tumor cells; however, the role of shear in regulating this process in metastatic cells is unknown. In this study, the role of shear in regulating cell surface expression of E-cadherin was investigated. We found that exposure to venous shear (shear rate, 200/s) induced internalization of E-cadherin in adherent metastatic oesophageal tumor cells (OC-1 tumor cell line). Internalized E-cadherin was found localized to Rab5-positive endosomes and was not present in lysosomes. As the Src family of tyrosine kinase have been implicated in regulating cadherin expression, we investigated the role of shear in regulating E-cadherin through Src activity. Pretreatment of OC-1 cells with the specific Src kinase inhibitor 4-amino-5- (4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1) prevented shear-induced internalization of E-cadherin. Direct measurement of Src activity (phosphorylation on Y416) showed that Src is activated in sheared OC-1 cells and that the shear-induced increase in phospho-Src is inhibited by the presence of PP1. Moreover, we show that shear stress significantly increased the invasive capacity of OC-1 cells (P < 0.001), a process inhibited by the presence of PP1. These results indicate a novel role for shear in regulating the endocytosis of E-cadherin and invasiveness in metastatic cells.
Lawler
Karen
K
Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland.
O'Sullivan
Gerald
G
Long
Aideen
A
Kenny
Dermot
D
D015820:Cadherins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival; D003600:Cytosol / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D013314:Stress, Mechanical; D020696:rab5 GTP-Binding Proteins / Q000378:metabolism
D015820:Cadherins; D039302:Integrin alphaVbeta3; D020696:rab5 GTP-Binding Proteins