title: Cooperation of amphiregulin and insulin-like growth factor-1 inhibits Bax- and Bad-mediated apoptosis via a protein kinase C-dependent pathway in non-small cell lung cancer cells.
abstract: Amphiregulin (AR) and insulin-like growth factor-1 (IGF1) are growth factors known to promote non-small cell lung cancer (NSCLC) survival. We have previously published that 1) AR and IGF1, secreted by H358 NSCLC cells, cooperate to protect those cells and H322 NSCLC cells from serum-starved apoptosis; 2) H358 cells resist Bax-induced apoptosis through an inhibition of Bax conformational change. We show here that the antiapoptotic activity of the AR/IGF1 combination is specifically abolished by the PKC inhibitors calphostin C and staurosporine, but not by the MAPK and phosphatidylinositol 3-kinase inhibitors PD98059 and wortmannin, suggesting the involvement of a PKC-dependent and MAPK- and phosphatidylinositol 3-kinase-independent survival pathway. The PKCdelta inhibitor rottlerin restores apoptosis induced by serum deprivation. In addition, phosphorylation of PKCdelta and PKCzeta/lambda, but not of PKCalpha/beta(II), increases in serum-starved H358 cells and in H322 cells treated with an AR/IGF1 combination and is blocked by calphostin C. The combination of AR and IGF1 increases p90(rsk) and Bad phosphorylation as well as inhibiting the conformational change of Bax by a PKC-dependent mechanism. Finally, PKCdelta, PKCzeta, or p90(rsk) small interfering RNAs block the antiapoptotic activity of AR/IGF1 combination but have no effect on partial apoptosis inhibition observed with each factor used alone. Constitutively active PKC expression inhibits serum deprivation-induced apoptosis, whereas a catalytically inactive form of p90(rsk) restores it. Thus, AR and IGF1 cooperate to prevent apoptosis by activating a specific PKC-p90(rsk)-dependent pathway, which leads to Bad and Bax inactivation. This signaling pathway is different to that used by single factor.
authors.affiliation: Groupe de Recherche sur le Cancer du Poumon, INSERM U578, Institut Albert Bonniot, La Tronche, France.
authors.forename: Amandine
authors.initials: A
authors.lastname: Hurbin
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Coll
authors.forename: Laurence
authors.initials: L
authors.lastname: Dubrez-Daloz
authors.forename: Bernard
authors.initials: B
authors.lastname: Mari
authors.forename: Patrick
authors.initials: P
authors.lastname: Auberger
authors.forename: Christian
authors.initials: C
authors.lastname: Brambilla
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Favrot
mesh_terms: D066258:Amphiregulin; D000730:Androstadienes / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000503:physiopathology*; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000502:physiology; D045744:Cell Line, Tumor; D016895:Culture Media, Serum-Free; D066255:EGF Family of Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006023:Glycoproteins / Q000502:physiology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000502:physiology; D008175:Lung Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008954:Models, Biological; D009281:Naphthalenes / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D019311:Staurosporine / Q000494:pharmacology; D000077191:Wortmannin; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D000730:Androstadienes; C494819:BAD protein, human; C494826:BAX protein, human; D002352:Carrier Proteins; D016895:Culture Media, Serum-Free; D066255:EGF Family of Proteins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D007527:Isoenzymes; D009281:Naphthalenes; D000081082:Phosphoinositide-3 Kinase Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D007334:Insulin-Like Growth Factor I; D011493:Protein Kinase C; D019311:Staurosporine; C058819:calphostin C; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin