The Last Secrets For Docetaxel E7080

We examined CCS derived Docetaxel cell lines and observed that cMet was expressed and phosphorylated on tyrosine residues within the kinase Docetaxel domain in two of the three lines during normal growth.

To test the importance of c Met signaling in CCS, we examined cell viability after inhibiting c Met expression. Lentivirally expressed c Met directed shRNA was transduced into CCS cells. c Met directed shRNA greatly decreased DTC 1 or CCS292 viability whereas infection of control HEK293 cells had no effect on viability. We then explored potential mechanisms for c Met activation. E7080 Since activating c Met mutations have been identified in several cancers, we fully sequenced c met exons encoding the juxtamembrane domain through the tyrosine kinase domain. No activating mutations were detected in any of the three CCS cell lines tested. We next tested whether c Met activation could be mediated through an autocrine mechanism. HGF expression was assayed by ELISA of conditioned media derived from CCS cell lines.

CCS cells cultured in Matrigel invasion wells demonstrated a small degree of invasion in the presence of fresh serum containing growth media. However, invasion and migration was greatly enhanced when CCS292 conditioned media was placed below the membrane. Inhibition of MET expression significantly reduced chemotaxis. The simultaneous expression of E7080 c Met and HGF by CCS292 cells and the basal level of phospho c Met suggest that c Met may be activated by an autocrine pathway. The recent identification of a fully human monoclonal anti HGF antibody, offered an opportunity to study the effect of HGF inhibition on CCS. To demonstrate the activity of AMG 102 on CCS derived HGF, 501mel cells were treated with CCS conditioned media that had been pretreated with AMG 102. At all concentrations tested, AMG 102 completely blocked cMet activation.

The data using either an inhibitor of HGF or the c Met kinase inhibitor suggest that c Met plays a vital role in a subset of CCS and that its activity plays a dominant role in stimulation of two pathways central to cell proliferation and survival.