Intracellular mechanics and TBX3 expression jointly dictate the spreading mode of melanoma cells in 3D environments

Abstract

AbstractCell stiffness and T-box transcription factor 3 (TBX3) expression have been identified as biomarkers of melanoma metastasis in 2D environments. This study aimed to determine how mechanical and biochemical properties of melanoma cells change during cluster formation in 3D environments. Vertical growth phase (VGP) and metastatic (MET) melanoma cells were embedded in 3D collagen matrices of 2 and 4 mg/ml collagen concentrations, representing low and high matrix stiffness. Mitochondrial fluctuations, intracellular stiffness, and TBX3 expression were quantified before and during cluster formation. In isolated cells, mitochondrial fluctuations decreased and intracellular stiffness increased with increase in disease stage from VGP to MET and increase in matrix stiffness. TBX3 was overexpressed in soft matrices but diminished in stiff matrices for VGP and MET cells. Cluster formation of VGP cells was excessive in soft matrices but limited in stiff matrices, whereas for MET cells it was limited in soft and stiff matrices. In soft matrices, VGP cells did not change the intracellular properties, whereas MET cells exhibited increased mitochondrial fluctuations and decreased TBX3 expression. In stiff matrices, mitochondrial fluctuations and TBX3 expression increased in VGP and MET, and intracellular stiffness increased in VGP but decreased in MET cells. Mitochondrial activity, cellular stiffness, and TBX3 expression jointly affected cluster formation and metastasis in melanoma with contributions that vary with changes in environmental properties. This study highlights the importance of considering the biophysical and biochemical properties of the malignant cells and the extracellular environment for advancing targeted melanoma therapies.