Although prostate cancer PC 3 cells are responsive to exogenous selleck chemicals HGF, our previous study showed that these cells exhibit a high basal level of autophosphorylated c Met, suggesting that c Met could be constitutively acti vated even in the absence of exogenous HGF. How ever, whether such constitutive c Met activation occurs in an autocrine Inhibitors,Modulators,Libraries manner is controversial. Some studies suggest the existence of an HGFc Met autocrine loop, whereas others indicate that PC 3 cells do not express HGF. The current study examines the expression and function of HGF produced by PC 3 cells and the response of these cells to an anti HGF neutralizing antibody or the small molecule Met kinase inhibitor, BMS 777607.

Results HGF mRNA could be detected in PC 3 however Inhibitors,Modulators,Libraries secreted HGF is not consistent with the purified HGF protein We first tested the gene expression of both the HGF ligand and c Met receptor in PC 3 and DU145 cells. subunit of purified recombinant human HGF. CM of Inhibitors,Modulators,Libraries PC 3 was not functional To determine whether the released HGF possessed biological function, serum starved DU145 cells were incubated with CM from PC 3 cells. DU145 cells were used because these prostate cancer cells do not phos phorylate c Met without exogenous HGF. Unlike pure HGF, CM from PC 3 cells could not induce either scattering or migration in DU145 cells. Fur thermore, CM without serum failed to induce phosphorylation of c Met in the catalytic residues and downstream molecules ERK and Akt, which could be achieved by add ing pure HGF. To rule out the possibility that the secreted HGF may be inactivated in the ab sence of serum, CM with 10% FBS was tested.

The results showed that c Met was not phosphorylated by serum containing CM. PC 3 Inhibitors,Modulators,Libraries was not responsive to the anti HGF neutralizing antibody The results of Figure 2 shown that CM from PC 3 cells cannot activate c Met in DU145 cells. a Inhibitors,Modulators,Libraries cell line which does not express the HGF ligand but has the c Met re ceptor. To explore the functional effect of the secreted HGF on PC 3 cells themselves, cells selleck screening library were incubated with 10 ugml of an anti HGF neutralizing antibody. This dose of the antibody, shown to be sufficient to neutralize HGF, did not reduce PC 3 cell proliferation, colony formation or migration, as compared to nIgG. Anti HGF neutralizing antibody did not block constitutive c Met signaling in PC 3 To confirm that the anti HGF antibody could block the c Met pathway, PC 3 cells were incubated with the anti HGF antibody under various conditions. Although phos phorylated c Met and downstream targets such as Akt and ERK were suppressed by the anti HGF antibody in a dose dependent fashion in the presence of exogenous HGF, in the absence of HGF, these signaling molecules were not eliminated by the anti HGF antibody as com pared to nIgG.