Cyclic mechanical strain alters tissue‐factor activity in rat osteosarcoma cells cultured on a titanium substrate

Abstract

Tissue factor (TF), a transmembrane glycoprotein, plays a role in the initiation of blood coagulation at sites of vascular injury. Activated products of coagulation may then enhance inflammatory responses. The present investigation assesses the ability of rat osteosarcoma (UMR-106) cells cultured on titanium alloy (Ti6Al4V) to express differential surface TF activity in response to cyclic mechanical strain. Strains ranged from -2000 micro-strain to +2000 micro-strain, and durations from 5, 10, and 20 min per day over 5 days to 24 h continuous stimulation. ROS cells exhibited significant TF activity as demonstrated by the conversion of Factor X to Factor Xa. Strains of +2000 micro-strain with 5-20-min duration exhibited decreased TF activity with duration from 1.4E-04 nM/cell to 8.7E-05 nM/cell. Additionally, ROS cells stimulated with calcium ionophore (A23187) exhibited at least twice the activity of nonstimulated cells. Strains of +1340 micro-strain with 5-20-min duration exhibited an increasing trend with 4.15E-05 nM/cell to 7.38E-05 nM/cell. Strain direction had no significant effect on TF activity. Thus, both mechanical and chemical stimuli induce differential expression of TF activity by ROS cells cultured on Ti6Al4V, a phenomenon that may potentiate or regulate the inflammatory responses associated with the implantation of orthopedic biomaterials.

Cyclic Stretch-Induced Mechanical Stress Applied at 1 Hz Frequency Can Alter the Metastatic Potential Properties of SAOS-2 Osteosarcoma Cells

“…SAOS-2 cells were assessed using atomic force microscopy, confocal microscopy, and cell-based assays. As cyclic mechanical strain has been reported to affect osteosarcoma cell biology depending on the frequency by which the stretch is applied to cells [38], we started the investigation by screening the best frequency capable of inducing the widest biological response. Our results demonstrated that a 1 Hz frequency of mild mechanical stretching (corresponding to 0.5% Ɛ elongation) applied for 3 days was able to increase the proliferation rate (Supplementary Figure S1A).…”

“…Mechanical stresses from the microenvironment have been reported to regulate the PI3K/Akt signaling pathway (the most activated downstream effectors in the oncogenic landscape), promoting the expression of MMP-2 and MMP-9, thus degrading ECM and enabling osteosarcoma cell invasion and metastasis [29][30][31]. Several MMPs have been associated with mature invadopodia [38], including MMP-2, which was found to have an upregulated expression following mechanical stimulation [44].…”