Comparison of Phosphoinositide-Specific Phospholipase C Expression Panels of Human Osteoblasts Versus MG-63 and Saos Osteoblast-Like Cells

Abstract

Background: A large number of phospholipase C (PLC) enzymes, both mRNA transcripts and proteins, have been detected in osteoblasts, corroborating the importance of calcium regulation in bone tissue. MG-63 and SaOS-2 human osteosarcoma cell lines are actually considered osteoblast-like cells, and are therefore widely used as experimental models for osteoblasts. Objectives: Our aim was to verify whether MG-63 or SaOS-2 cells might also represent appropriate experimental osteoblast models for signal transduction studies, with special regard to the phosphoinositide (PI) pathway. We analyzed the expression and the subcellular distribution of enzymes related to calcium signal transduction (the PI-specific PLC family), which are known to possess high cell/tissue specificity. Materials and Methods:The expression of PLC genes was analyzed by performing RT-PCR experiments. The presence of PLC enzymes and their subcellular distribution within the cells was analyzed with immunofluorescence experiments. Results: Osteoblasts, MG-63 cells, and SaOS-2 cells have expression panels similar to those of PLC enzymes. However, slight differences were found in the expression of enzymes belonging to the PLCη subfamily. Conclusions: MG-63 and SaOS-2 osteosarcoma cell lines might not represent appropriate experimental models for studies that aim to analyze signal transduction in osteoblasts.

Expression and Localization of Phosphoinositide-Specific Phospholipases C in Cultured, Differentiating and Stimulated Human Osteoblasts

“…In this perspective, PLC enzymes were described to be involved in the regulation of mechanical loading, with special regard to PLC β2. In the present experiments, no transcript of PLCB2 was visualized in HOB cells shortly cultured after thawing (day 0), accordingly to literature data [51,59], but PLC β2 was observed in the perinuclear area of the cytoplasm. PLC β2 was mainly expressed in hematopoietic cell lines [60,61].…”

Phosphoinositide-specific phospholipase C isoforms are conveyed by osteosarcoma-derived extracellular vesicles

“…Previous reports described PI-PLC η2 in selected areas of the cytoplasm, highly concentrated close to the plasma membrane. With special regard to osteoblasts, the presence of PI-PLC η2 at the membrane level might be related to its role in bone remodeling, due to its high sensitivity to calcium levels, thereby coordinating both intracellular and extracellular stimuli (Lo Vasco et al 2016). Indeed, enzymes belonging to the PLC η sub-family, highly sensitive to changes in calcium levels, can modulate or sustained release of Ca2+ from intracellular stores through IP3 production, probably recruiting further PLC isoforms.…”

Supernatants From Human Osteosarcoma Cultured Cell Lines Induce Modifications in Growth and Differentiation of THP-1 Cells and Phosphoinositide- Specific Phospholipase C Enzymes

“…Literature data described the role of the PLC signal transduction in development and differentiation pathway [11][12][13][14]. The expression panel of PLCs is localization of PLC enzymes differs depending on the isoform and varies under different conditions; activation of quiescent cells with different stimuli induced variation of the PLCs expression [22][23][24][25], and abnormal expression of PLCs was described in nervous anomalies [3,13,14,16,17,[26][27][28] and tumors [17,18,23,24,29]. PLC inhibition [22,23] or silencing [20,21,30] can modify the growth and survival of selected tumors.…”