In analogy with past reports, we located that the Ras MAPK pathway was crucial for proliferation of ANBL 6 cells simply because the MEK1 2 inhibitors PD98059 and U126 each inhibited proliferation in these cells.
6A,B, we examined the skill of HGF and IL 6 to induce phosphorylation of Gab1 and Shp2 in ANBL 6 cells. Because these cells Fingolimod produce HGF endoge nously resulting in low c Met expression, we preincubated the cells over night with anti HGF serum to increase c Met expression before addition of IL 6 for 10 min with or without the presence of the c Met kinase inhibitor as indicated in Fig. 6A,B. IL 6 induced low phosphorylation of tyrosine 542 on Shp2 under these conditions. In contrast, HGF induced low but detectable phosphorylation of Gab1. Importantly, in the presence of HGF, the phosphorylation of Shp2 was further increased with IL 6. Furthermore, the Gab1 and Shp2 phosphorylation induced with the combination of HGF and IL 6 was markedly reduced in the presence of the c Met kinase inhibitor.
In the presence of IL 6 and endogenous HGF, NSC 87877 inhibited phosphorylation of p44 42 MAPK in ANBL 6 cells in a dose dependent manner, without affecting the phosphorylation of STAT3. These results suggest that whereas Shp2 is involved in p44 42 MAPK activation, it has no role in STAT3 phosphorylation which is entirely dependent on IL 6 in this setting. NSCLC Furthermore, the synergy observed in Ras MAPK signaling is dependent on the synergy in phosphatase activity of Shp2. The main nding reported here is that IL 6 induced proliferation may be dependent on c Met signaling in myeloma cells. The potentiating effect of HGF c Met on IL 6 signaling could be explained by two mechanisms: IL 6 increased the level of c Met on the cell surface of myeloma cells making cells more sensitive to HGF, and IL 6 relied on HGF c Met to fully activate the RasMAPK pathway possibly through Shp2 activation.
A recent publication Cell Cycle inhibitor also indicates that the level of c Met expression is important for the survival of myeloma cells as partly downregulation of c Met lead to myeloma cell death. Moreover, in vivo induction of the IGF 1 receptor has been reported in the murine myeloma model 5T33MM, and this induction was necessary for biological effects of IGF 1 in these experiments.
Monday, March 25, 2013
A Few Fingolimod Cell Cycle inhibitor Frauds And Ways To Protect Against It
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