title: Type II cGMP-dependent protein kinase inhibits EGF-induced MAPK/JNK             signal transduction in breast cancer cells.
abstract: Our previous research data showed that type II cGMP-dependent protein kinase (PKGII) inhibited EGF-induced MAPK/ERK-mediated signal transduction through blocking the phosphorylation of EGFR caused by EGF. Since EGFR also mediates other MAPK-mediated signal transduction pathways, this study was designed to investigate whether PKGII inhibits EGF-induced MAPK/c-Jun N-terminal kinase (JNK) signal transduction. MCF-7 human breast cancer cells were infected with adenoviral constructs encoding the cDNA of PKGII (pAd-PKGII) to increase the expression of PKGII and treated with 8-pCPT-cGMP to activate the enzyme. Western blotting was applied to detect the phosphorylation/activation of EGFR, JNK, MKK7 and c-Jun. The Pull-down method was used to detect the activation of Ras protein. Co-IP was used to analyze the binding between Grb2 and Sos1. TUNEL staining was used to detect the apoptosis of MCF-7 cells. The results showed that EGF treatment increased the phosphorylation of EGFR, the binding between Grb2 and Sos1, the activation of Ras, and the phosphorylation/activation of MKK7, JNK and c-Jun, but decreased the apoptosis of the cells. Increase of PKGII activity through infection with pAd-PKGII and stimulation with 8-pCPT-cGMP efficiently reversed the above changes caused by EGF. The results suggest that PKGII also inhibits EGF-induced MAPK/JNK-mediated signal transduction and further confirmed that PKGII can block the activation of EGFR.
authors.affiliation: Laboratory Medicine, School of Medical Science, Jiangsu University, Zhenjiang, Jiangsu, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Lan
authors.forename: Yongchang
authors.initials: Y
authors.lastname: Chen
authors.forename: Jianrong
authors.initials: J
authors.lastname: Sang
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Lu
authors.initials: L
authors.lastname: Jiang
authors.forename: Yan
authors.initials: Y
authors.lastname: Tao
mesh_terms: D017209:Apoptosis; D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D062967:Cyclic GMP-Dependent Protein Kinase Type II; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D051380:GRB2 Adaptor Protein / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D048688:MAP Kinase Kinase 7 / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D010766:Phosphorylation; D020837:SOS1 Protein / Q000378:metabolism; D013873:Thionucleotides / Q000494:pharmacology; D018631:ras Proteins / Q000096:biosynthesis / Q000378:metabolism
chemical_list: D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D020837:SOS1 Protein; D013873:Thionucleotides; C055656:8-((4-chlorophenyl)thio)cyclic-3',5'-GMP; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D062967:Cyclic GMP-Dependent Protein Kinase Type II; D017869:Cyclic GMP-Dependent Protein Kinases; C569729:PRKG2 protein, human; D048031:JNK Mitogen-Activated Protein Kinases; D048688:MAP Kinase Kinase 7; C482569:MAP2K7 protein, human; D018631:ras Proteins; D006152:Cyclic GMP