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: Ting Lan, Yongchang Chen, Jianrong Sang, Yan Wu, Ying Wang, Lu Jiang, Yan Tao
• Journal: Oncology reports (Oncol Rep) Vol. 27 Issue 6 Pg. 2039-44 (Jun 2012) ISSN: 1791-2431 [Electronic] Greece
• PMID: 22427012 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• GRB2 Adaptor Protein
• GRB2 protein, human
• SOS1 Protein
• Thionucleotides
• 8-((4-chlorophenyl)thio)cyclic-3',5'-GMP
• Epidermal Growth Factor
• ErbB Receptors
• Cyclic GMP-Dependent Protein Kinase Type II
• Cyclic GMP-Dependent Protein Kinases
• PRKG2 protein, human
• JNK Mitogen-Activated Protein Kinases
• MAP Kinase Kinase 7
• MAP2K7 protein, human
• ras Proteins
• Cyclic GMP

Topics

• Apoptosis
• Breast Neoplasms (metabolism)
• Cell Line, Tumor
• Cyclic GMP (analogs & derivatives, pharmacology)
• Cyclic GMP-Dependent Protein Kinase Type II
• Cyclic GMP-Dependent Protein Kinases (metabolism)
• Epidermal Growth Factor (metabolism, pharmacology)
• ErbB Receptors (metabolism)
• Female
• GRB2 Adaptor Protein (metabolism)
• Humans
• JNK Mitogen-Activated Protein Kinases (metabolism)
• MAP Kinase Kinase 7 (metabolism)
• MAP Kinase Signaling System (drug effects)
• Phosphorylation
• SOS1 Protein (metabolism)
• Thionucleotides (pharmacology)
• ras Proteins (biosynthesis, metabolism)