Supernatants from human osteosarcoma cultured cell lines induce modifications in growth and differentiation in THP-1 cells and in Phosphoinositide specific Phospholipase C enzymes

Introduction: molecular components in the microenvironment could affect cell growth, survival/apoptosis and proliferation. Immune system cells respond to molecules, such as cytokines, chemokines and growth factors, produced by the tumor and released in the surrounding microenvironment. Methods: we evaluated the morphological and functional changes in THP-1 cells cultured in culture medium mixed with the culture supernatant of one of three different osteosarcoma (OS) cell lines, namely 143B, HS888 and MG-63 cells. We analyzed the effect of supernatant from OS cultures upon morphology and growth of THP-1 cells, and expression of Phosphoinositide-specific PLC enzymes (PLCs). Results: in supernatants from each OS cell line we identified the presence of selected ILs, of TNF and GM-CSF. Each OS derived supernatant differently modified the growth rate of THP-1 cells, depending on the OS cell line. OS supernatants in the in vitro microenvironment of cells’ culture greatly modified the panel of expression of PLC enzymes expressed by THP-1 cells. THP-1 cells differently express PLC enzymes, depending on the origin of the supernatant. The differences in PLCs’ expression induced by adding OS supernatants to the cultures of THP-1 cells resulted statistically significant for PLCB1 and PLCG2 genes. Conclusions: OS supernatants induce the differentiation of THP-1 cells into macrophages. THP-1 cells cultured in OS supernatants express different panels of expression of PLC enzymes. The panel of expression of PLC enzymes differs during the differentiation of monocyte/macrophage lineage THP-1 cells.