Premium
Down‐modulation of erbB2 activity is necessary but not enough in the differentiation of 3T3‐L1 preadipocytes
Author(s) -
Pagano Eleonora,
Coso Omar,
Calvo Juan Carlos
Publication year - 2007
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.21621
Subject(s) - adipogenesis , 3t3 l1 , mapk/erk pathway , microbiology and biotechnology , p38 mitogen activated protein kinases , phosphorylation , cell growth , 3t3 cells , kinase , chemistry , cellular differentiation , endocrinology , cancer research , medicine , biology , biochemistry , transfection , mesenchymal stem cell , gene
The high incidence of obesity‐related pathologies, led to the study of the mechanisms involved in preadipose cell proliferation and differentiation. Here, we demonstrate that modulation of erbB2, plays a fundamental role during proliferation and adipogenic induction of preadipocytes. Using 3T3‐L1 cells as model, we demonstrate that EGF (10 nM, 5 min) in addition to stimulate receptor tyrosine phosphorylation of both erbB2 and EGFR, is able to induce the heterodimer erbB2‐EGFR. We treated proliferating 3T3‐L1 cells with two inhibitors, AG 825 (IC 50 0.35 µM, 54 times more selective for erbB2 than for EGFR, IC 50 19 µM), and AG 879 (IC 50 of 1 µM for erbB2 versus 500 µM for EGFR). We found that both inhibited the proliferation on a dose‐dependent basis, reaching a 30% maximal inhibition at 100 µM ( P < 0.001) for AG825, and a 20% maximal inhibition at 10 µM ( P < 0.001) for AG 879. These results involve erbB2 in 3T3‐L1 proliferation. When studying the differentiation process, we found that the action of MIX–Dexa immediately activates MEK, JNK and p38 kinases. We observed that PD98059 and SP600125 (MEK–ERK and JNK inhibitors, respectively) added 1 h prior to the MIX–Dexa induction produced a decrease in erbB2 expression after 6 h, which is even greater than the one produced by the inducers, MIX–Dexa. This work supports erbB2 as a key factor in 3T3‐L1 adipogenesis, acting mostly and not only during the proliferative phase but also during the differentiation through modulation of both its expression and activity. J. Cell. Biochem. 104: 274–285, 2008. © 2007 Wiley‐Liss, Inc.