title: Essential role of the cGMP/PKG signaling pathway in regulating the proliferation and survival of human renal carcinoma cells.
abstract: Phosphodiesterase type 5 (PDE5) plays a key role in regulating the intracellular cyclic GMP (cGMP) concentration, which influences anti-proliferative and pro-apoptotic mechanisms in multiple carcinomas. PDE5 inhibitors, such as exisulind and its analogs have anticancer activities. In this study, we found that suppressing PDE5 gene expression by PDE5 siRNA inhibited cell proliferation and induced apoptosis in OS-RC-2 human renal cell carcinoma cells. These effects were enhanced by 8-Br-cGMP, a cell membrane permeable cGMP derivative, and were inhibited by KT5823, a protein kinase G (PKG) inhibitor, indicating that PKG was activated by intracellular cyclic GMP. In addition, there was a reduction in both the mRNA and protein expression of cyclin D1, while p21 protein expression was increased; the reduction in cyclin D1 expression was blocked by the proteasome inhibitor, MG132, or c-Jun N-terminal kinase (JNK) inhibitor; both β-catenin and JNK were phosphorylated by activated PKG. Furthermore, p21 protein expression was decreased in Sp1 siRNA transfected-cells treated with 8-Br-cGMP, indicating that p21 may be partly controlled by the PKG activation through Sp1. Furthermore, we found that PKG Iβ was responsible for the anticancer activities. Our findings indicate that the downregulation of PKG-activated genes, such as cyclin D1 partly accounts for the pro-apoptotic effects in PDE5 siRNA-transfected OS-RC-2 cells.
authors.affiliation: Department of Urologic Surgery, Ningbo Urology and Nephrology Hospital, Ningbo, Zhejiang 315000, P.R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Wenzhou Key Laboratory of Surgery, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang 325000, P.R. China.
authors.forename: Jianjian
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Urologic Surgery, Ningbo Urology and Nephrology Hospital, Ningbo, Zhejiang 315000, P.R. China.
authors.forename: Xuping
authors.initials: X
authors.lastname: Yao
authors.affiliation: Department of Urologic Surgery, Ningbo Yinzhou People's Hospital, Zhejiang 315000, P.R. China.
authors.forename: Guobin
authors.initials: G
authors.lastname: Weng
authors.affiliation: Department of Pediatric Rheumatology and Immunology, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315000, P.R. China.
authors.forename: Ling
authors.initials: L
authors.lastname: Wu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002227:Carbazoles / Q000494:pharmacology; D002292:Carcinoma, Renal Cell / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000235:genetics / Q000378:metabolism*; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D058986:Phosphodiesterase 5 Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D015398:Signal Transduction; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D013467:Sulindac / Q000031:analogs & derivatives / Q000494:pharmacology; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D002227:Carbazoles; D050759:Cyclin-Dependent Kinase Inhibitor p21; D058986:Phosphodiesterase 5 Inhibitors; D016329:Sp1 Transcription Factor; D051176:beta Catenin; C073601:KT 5823; D019938:Cyclin D1; D013467:Sulindac; C016276:8-bromocyclic GMP; D048031:JNK Mitogen-Activated Protein Kinases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D006152:Cyclic GMP; C025463:sulindac sulfone