RESUMEN
Deregulated expression of microRNAs has been associated with angiogenesis. Studying the miRNome of locally advanced breast tumors we unsuspectedly found a dramatically repression of miR-204, a small non-coding RNA with no previous involvement in tumor angiogenesis. Downregulation of miR-204 was confirmed in an independent cohort of patients and breast cancer cell lines. Gain-of-function analysis indicates that ectopic expression of miR-204 impairs cell proliferation, anchorage-independent growth, migration, invasion, and the formation of 3D capillary networks in vitro. Likewise, in vivo vascularization and angiogenesis were suppressed by miR-204 in a nu/nu mice model. Genome-wide profiling of MDA-MB-231 cells expressing miR-204 revealed changes in the expression of hundred cancer-related genes. Of these, we focused on the study of pro-angiogenic ANGPT1 and TGFßR2. Functional analysis using luciferase reporter and rescue assays confirmed that ANGPT1 and TGFßR2 are novel effectors downstream of miR-204. Accordingly, an inverse correlation between miR-204 and ANGPT1/TGFßR2 expression was found in breast tumors. Knockdown of TGFßR2, but not ANGPT1, impairs cell proliferation and migration whereas inhibition of both genes inhibits angiogenesis. Taken altogether, our findings reveal a novel role for miR-204/ANGPT1/TGFßR2 axis in tumor angiogenesis. We propose that therapeutic manipulation of miR-204 levels may represent a promising approach in breast cancer.
Asunto(s)
Angiopoyetina 1/biosíntesis , Neoplasias de la Mama/irrigación sanguínea , Neoplasias de la Mama/metabolismo , MicroARNs/biosíntesis , Proteínas de Neoplasias/biosíntesis , Neovascularización Patológica/metabolismo , Proteínas Serina-Treonina Quinasas/biosíntesis , ARN Neoplásico/biosíntesis , Receptores de Factores de Crecimiento Transformadores beta/biosíntesis , Angiopoyetina 1/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/terapia , Femenino , Humanos , Células MCF-7 , MicroARNs/genética , Proteínas de Neoplasias/genética , Neovascularización Patológica/genética , Neovascularización Patológica/patología , Neovascularización Patológica/terapia , Proteínas Serina-Treonina Quinasas/genética , ARN Neoplásico/genética , Receptor Tipo II de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/genéticaRESUMEN
Breast cancer is the second-leading cause of death among Mexican women >35 years of age. At the molecular level, changes in many genetic pathways have been reported to be associated with this neoplasm. To analyze these changes, we determined gene expression profiles and chromosomal structural alterations in tumors from Mexican women. We obtained mRNA to identify expression profiles with microarray technology, and DNA to determine amplifications and deletions, in 10 fresh sporadic breast tumor biopsies without treatment, as well as in 10 nonaffected breast tissues. Expression profiles were compared with genetic changes observed by comparative genomic hybridization (CGH). We compared the expression profiles against the structural alterations from the studied genes by means of microarrays; at least 17 of these genes correlated with DNA copy number alterations. We found that the following genes were overexpressed: LAMC1, PCTK3, CCNC, CCND1, FGF3, PCTK2, L1CAM, BGN, and PLXNB3 (alias PLEXR). Underexpressed genes included CASP9, FGR, TP73, HSPG2, and ERCC1; genes turned off included FRAP1, EPHA2 (previously ECK), IL12A, E2F5, TNFRSF10B, TNFRSF10A, EFNB3, and BCL2. The results will allow us, in the near future, to outline genes that could serve as diagnostic, prognostic, or target therapy markers for the Mexican population.
