TNF contributes with RAC3-induced malignant transformation

MILENI SOARES MACHADO; LAURA C. PANELO; MARÍA C. LIRA; FRANCISCO D. ROSA; GABRIELA MARINO; MARÍA F. RUBIO; ALEJANDRO J. URTREGER; MÓNICA A. COSTAS

Mar del Plata

Congreso; LXIII Reunión Científica de la Sociedad Argentina de Investigación Clínica (SAIC); 2018

Sociedad Argentina de Investigación Clínica (SAIC)

RAC3 is a coactivator of steroid receptors and transcription factors and an important oncogene in tumor development. We have previously demonstrated that inflammatory cytokines increase the RAC3 expression and that high levels of this molecule could transform non-tumor cells into cancer stem cells. The aim of this work was to investigate if the inflammatory cytokine TNF could contribute to RAC3 transforming effect, maintaining or increasing stem properties. HEK293 cells (human embryonic kidney) overexpressing RAC3 (tumor) or not (non-tumoral) and other tumor cell lines (HeLa and T47D, silencing or not RAC3) were stimulated with TNF (10 ng/ml) or vehicle and analyzed for their mesenchymal properties, migratory, invasive behavior and signals that contribute to the stem phenotype. We found that TNF potentiated the RAC3 overexpression effects, increasing the mesenchymal phenotype, through the decrease of E-cadherin, increase of Vimentin (both by WB) and SNAIL (qPCR) respect to cells overexpressing RAC3 without TNF stimulus. It also increased migration capacity (wound assay) and metalloprotease production (zymography). In addition, TNF induced the nuclear translocation of β-Catenin (IF), and also, the transcriptional activity of TCF-b-Catenin (Luciferase reporter assay) under high expression of RAC3. All these actions were significantly decreased by sulfasalazine, an inhibitor of IKK. Our results demonstrate that TNF potentiates the transforming action of RAC3 overexpression, contributing to increase the mesenchymal phenotype and transduction signals of NF-kB and b-Catenin- dependent, both involved in the preservation of cancer stem cells. Therefore, our results suggest that inflammatory microenvironment could contribute to the initiation and propagation of tumors, increasing the expression of RAC3 and then enhancing its biological action.