title: Silencing cAMP-response element-binding protein (CREB) identifies CYR61 as a tumor suppressor gene in melanoma.
abstract: Metastatic progression of melanoma is associated with overexpression and activity of cAMP-response element-binding protein (CREB). However, the mechanism by which CREB contributes to tumor progression and metastasis remains unclear. Here, we demonstrate that stably silencing CREB expression in two human metastatic melanoma cell lines, A375SM and C8161-c9, suppresses tumor growth and experimental metastasis. Analysis of cDNA microarrays revealed that CREB silencing leads to increased expression of cysteine-rich protein 61 (CCN1/CYR61) known to mediate adhesion, chemostasis, survival, and angiogenesis. Promoter analysis and chromatin immunoprecipitation assays demonstrated that CREB acts as a negative regulator of CCN1/CYR61 transcription by directly binding to its promoter. Re-expression of CREB in CREB-silenced cells rescued the low CCN1/CYR61 expression phenotype. CCN1/CYR61 overexpression resulted in reduced tumor growth and metastasis and inhibited the activity of matrix metalloproteinase-2. Furthermore, its overexpression decreased melanoma cell motility and invasion through Matrigel, which was abrogated by silencing CCN1/CYR61 in low metastatic melanoma cells. Moreover, a significant decrease in angiogenesis as well as an increase in apoptosis was seen in tumors overexpressing CCN1/CYR61. Our results demonstrate that CREB promotes melanoma growth and metastasis by down-regulating CCN1/CYR61 expression, which acts as a suppressor of melanoma cell motility, invasion and angiogenesis.
authors.affiliation: Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Andrey S
authors.initials: AS
authors.lastname: Dobroff
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Vladislava O
authors.initials: VO
authors.lastname: Melnikova
authors.forename: Gabriel J
authors.initials: GJ
authors.lastname: Villares
authors.forename: Maya
authors.initials: M
authors.lastname: Zigler
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Menashe
authors.initials: M
authors.lastname: Bar-Eli
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D055515:Cysteine-Rich Protein 61 / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000235:genetics; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism; D014183:Transplantation, Heterologous
chemical_list: C501848:CCN1 protein, human; C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D055515:Cysteine-Rich Protein 61; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2