Avaliação do papel biológico da enzima ácido graxo sintese (FASN) em células endoteliais linfáticas estimuladas ou não por células de melanoma

Author(s)

Débora Campanella Bastos

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2012-01-11

Examining board members

Edgard Graner; Oslei Paes de Almeida; Ricardo Della Coletta; Marinella Holzhausen; Jorge Esquiche León

• Advisor: Edgard Graner

Abstract

Fatty acid synthase (FASN) is responsible for de novo synthesis of long-chain fatty. FASN has emerged as a potential therapeutic target for human cancers since it's over expression is associated with depth of invasion and poor prognosis. Cerulenin and orlistat are pharmacological inhibitors of FASN and have been described as potential anti-tumor agents. Lymphatic vessels are the primary route of metastasis in several malignancies including melanomas. In previous studies performed in our laboratory, we demonstrated that FASN activity is essential for melanoma and oral squamous cell carcinoma progression, as its pharmacological inhibition with orlistat reduces lymphatic metastasis in both experimental intraperitoneal and subcutaneous melanomas and orthotopic tongue carcinomas. We also reported that cell culture medium previously conditioned by human melanoma cells in the presence of orlistat induces an anti-angiogenic phenotype mediated by VEGFA165b. Therefore, in order to understand a possible correlation between FASN and lymphangiogenesis, here we investigate the effects FASN inhibitors on the secretion of vascular endothelial growth factors (VEGF) -C and -D by murine (B16-F10) and human (SK-Mel-25) melanoma cells with the aid of qRT-PCR and ELISA assays. We also analyzed the effect of FASN blockage on tridimensional cultures of human lymphatic endothelial cells (HDLEC) and primary cultures of murine lymphatic endothelium. In addition, we also evaluated an indirect effect of the treatment with cerulenin and orlistat in SK-Mel-25 cells on HDLEC xx proliferation. The incubation of B16-F10 or SK-Mel-25 cells with cerulenin or orlistat modulated VEGF-C and -D expression by significantly inhibiting the former and increasing the latter. In addition, these drugs reduced the viability, proliferation, and migration as well as promoted apoptosis in human lymphatic endothelial cells (HDLEC). These compounds also inhibited lymphatic capillary formation in a murine ex vivo assay. Finally, conditioned media from orlistat-treated human melanoma cells resulted in an anti-lymphangiogenic phenotype. These data suggest that FASN inhibitiors reduce lymphangiogenesis by acting simultaneously in the lymphatic endothelium and melanoma cells. Taken together, the studies here presented explain, at least in part, the anti-metastatic effect of orlistat observed in experimental tumors and further suggest that FASN is a potential therapeutic target for melanomas (AU)

• FAPESP's process: 10/51090-1 - Evaluation of the biological role of fatty acid synthase (FASN) enzyme in lymphatic endothelial cells stimulated by malignant cells in culture
• Grantee: Débora Campanella Bastos
• Support Opportunities: Scholarships in Brazil - Doctorate