The tumor microenvironment promotes cancer progression and cell migration

// Viviana Salvatore 1 , Gabriella Teti 1 , Stefano Focaroli 1 , Maria Carla Mazzotti 2 , Antonio Mazzotti 3 , Mirella Falconi 1 1 DIBINEM, University of Bologna Department of Biomedical and Neuromotor Sciences, 40126 Bologna, Italy 2 DIMEC, University of Bologna, Department of Medical and Surgical Sciences, 40126 Bologna, Italy 3 Rizzoli Orthopaedhic Institute, 40136 Bologna, Italy Correspondence to: Mirella Falconi, email: mirella.falconi@unibo.it Keywords: tumor microenvironment, osteosarcoma, human fibroblasts, co-culture, tumor stroma Received: July 14, 2016 Accepted: November 04, 2016 Published: December 24, 2016 ABSTRACT The tumor microenvironment contributes to cancer progression, in part through interactions between tumor and normal stromal cells. This study analyzed morphological and molecular changes induced in co-cultured human fibroblasts (HFs) and the MG-63 osteosarcoma cell line. Co-cultured cell monolayers were morphologically analyzed using high resolution scanning electron microscopy (HR-SEM), and trans-well assays were performed to assess cell migration and invasion. Proteins involved in inflammatory responses, cancer cell invasion, and angiogenesis were assessed using western blotting. HR-SEM showed progressive spatial orientation loss by fibroblasts in contact with MG-63s, while MG-63s proliferated rapidly and invaded HF space. Trans-well assays showed enhanced MG-63 migration in the presence of HFs. IL-6 expression was increased in co-cultured HFs, possibly stimulated by TNF-α. HFs do not normally express YKL-40 but did so in co-culture. Band densitometric analyses showed that increasing YKL-40 expression was followed by VEGF overexpression, especially in MG-63s. Finally, our results confirmed fibroblasts as the main matrix metalloproteinase source in this tumor microenvironment. Our study sheds new light on how tumor-stroma interactions promote tumor development and progression, and may support identification of novel anti-cancer therapeutics.