The inhibition of aromatase alters the mechanical and rheological properties of non-small-cell lung cancer cell lines affecting cell migration (original) (raw)
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Journal of Biomedical Materials Research Part A, 2016
Biomechanical properties of the tumor microenvironment, including matrix/substrate stiffness, play a significant role in tumor evolution and metastasis. Epithelial to Mesenchymal Transition (EMT) is a fundamental biological process that is associated with increased cancer cell migration and invasion. The goal of this study was to investigate (1) how substrate stiffness modulates the migration behaviors of lung adenocarcinoma cells (A549) and (2) if stiffness-induced changes in cell migration correlate with biochemical markers of EMT. Collagen-coated polydimethylsiloxane (PDMS) substrates and an Ibidi migration assay were used to investigate how substrate stiffness alters the migration patterns of A549 cells. RT-PCR, western blotting and immunofluorescence were used to investigate how substrate stiffness alters biochemical markers of EMT, that is, E-cadherin and N-cadherin, and the phosphorylation of focal adhesion proteins. Increases in substrate stiffness led to slower, more directional migration but did not alter the biochemical markers of EMT. Interestingly, growth factor (i.e., Transforming Growth Factor-b) stimulation resulted in similar levels of EMT regardless of substrate stiffness. We also observed decreased levels of phosphorylated focal adhesion kinase (FAK) and paxillin on stiffer substrates which correlated with slower cell migration. These results indicate that substrate stiffness modulates lung cancer cell migration via focal adhesion signaling as opposed to EMT signaling.
Mechanical and Systems Biology of Cancer
Computational and Structural Biotechnology Journal
Mechanics and biochemical signaling are both often deregulated in cancer, leading to cancer cell phenotypes that exhibit increased invasiveness, proliferation, and survival. The dynamics and interactions of cytoskeletal components control basic mechanical properties, such as cell tension, stiffness, and engagement with the extracellular environment, which can lead to extracellular matrix remodeling. Intracellular mechanics can alter signaling and transcription factors, impacting cell decision making. Additionally, signaling from soluble and mechanical factors in the extracellular environment, such as substrate stiffness and ligand density, can modulate cytoskeletal dynamics. Computational models closely integrated with experimental support, incorporating cancer-specific parameters, can provide quantitative assessments and serve as predictive tools toward dissecting the feedback between signaling and mechanics and across multiple scales and domains in tumor progression.
2016
Biomechanical properties of the tumor microenvironment, including matrix/substrate stiffness, play a significant role in tumor evolution and metastasis. Epithelial to Mesenchymal Transition (EMT) is a fundamental biological process that is associated with increased cancer cell migration and invasion. The goal of this study was to investigate (1) how substrate stiffness modulates the migration behaviors of lung adenocarcinoma cells (A549) and (2) if stiffness-induced changes in cell migration correlate with biochemical markers of EMT. Collagen-coated polydimethylsiloxane (PDMS) substrates and an Ibidi migration assay were used to investigate how substrate stiffness alters the migration patterns of A549 cells. RT-PCR, western blotting and immunofluorescence were used to investigate how substrate stiffness alters biochemical markers of EMT, that is, E-cadherin and N-cadherin, and the phosphorylation of focal adhesion proteins. Increases in substrate stiffness led to slower, more directional migration but did not alter the biochemical markers of EMT. Interestingly, growth factor (i.e., Transforming Growth Factor-b) stimulation resulted in similar levels of EMT regardless of substrate stiffness. We also observed decreased levels of phosphorylated focal adhesion kinase (FAK) and paxillin on stiffer substrates which correlated with slower cell migration. These results indicate that substrate stiffness modulates lung cancer cell migration via focal adhesion signaling as opposed to EMT signaling.
Mechanical properties of fibroblasts depend on level of cancer transformation
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2014
Recently, it was revealed that tumor cells are significantly softer than normal cells. Although this phenomenon is well known, it is connected with many questions which are still unanswered. Among these questions are the molecular mechanisms which cause the change in stiffness and the correlation between cell mechanical properties and their metastatic potential. We studied mechanical properties of cells with different levels of cancer transformation. Transformed cells in three systems with different transformation types (monooncogenic N-RAS, viral and cells of tumor origin) were characterized according to their morphology, actin cytoskeleton and focal adhesion organization. Transformation led to reduction of cell spreading and thus decreasing the cell area, disorganization of actin cytoskeleton, lack of actin stress fibers and decline in the number and size of focal adhesions. These alterations manifested in a varying degree depending on type of transformation. Force spectroscopy by atomic force microscopy with spherical probes was carried out to measure the Young's modulus of cells. In all cases the Young's moduli were fitted well by log-normal distribution. All the transformed cell lines were found to be 40-80% softer than the corresponding normal ones. For the cell system with a low level of transformation the difference in stiffness was less pronounced than for the two other systems. This suggests that cell mechanical properties change upon transformation, and acquisition of invasive capabilities is accompanied by significant softening.
Mechanical Force Affects Expression of an In Vitro Metastasis-Like Phenotype in HCT-8 Cells
Biophysical Journal, 2010
Cancer deaths are primarily caused by metastases, not by the parent tumor. During metastasis, malignant cells detach from the parent tumor, and spread through the circulatory system to invade new tissues and organs. The physical-chemical mechanisms and parameters within the cellular microenvironment that initiate the onset of metastasis, however, are not understood. Here we show that human colon carcinoma (HCT-8) cells can exhibit a dissociative, metastasis-like phenotype (MLP) in vitro when cultured on substrates with appropriate mechanical stiffness. This rather remarkable phenotype is observed when HCT-8 cells are cultured on gels with intermediate-stiffness (physiologically relevant 21-47 kPa), but not on very soft (1 kPa) and very stiff (3.6 GPa) substrates. The cell-cell adhesion molecule E-Cadherin, a metastasis hallmark, decreases 4.73 5 1.43 times on cell membranes in concert with disassociation. Both specific and nonspecific cell adhesion decrease once the cells have disassociated. After reculturing the disassociated cells on fresh substrates, they retain the disassociated phenotype regardless of substrate stiffness. Inducing E-Cadherin overexpression in MLP cells only partially reverses the MLP phenotype in a minority population of the dissociated cells. This important experiment reveals that E-Cadherin does not play a significant role in the upstream regulation of the mechanosensing cascade. Our results indicate, during culture on the appropriate mechanical microenvironment, HCT-8 cells undergo a stable cell-state transition with increased in vitro metastasis-like characteristics as compared to parent cells grown on standard, very stiff tissue culture dishes. Nuclear staining reveals that a large nuclear deformation (major/minor axis ratio, 2:5) occurs in HCT-8 cells when cells are cultured on polystyrene substrates, but it is markedly reduced (ratio, 1:3) in cells grown on 21 kPa substrates, suggesting the cells are experiencing different intracellular forces when grown on stiff as compared to soft substrates. Furthermore, MLP can be inhibited by blebbistatin, which inactivates myosin II activity and relaxes intracellular forces. This novel finding suggests that the onset of metastasis may, in part, be linked to the intracellular forces and the mechanical microenvironment of the tumor.
Elastic modulus and migration capability of drug treated leukemia cells K562
Biochemical and Biophysical Research Communications, 2019
Leukemia is a commonly seen disease caused by abnormal differentiation of hematopoietic stem cells and blasting in bone marrow. Despite drugs are used to treat the disease clinically, the influence of these drugs on leukemia cells' biomechanical properties, which are closely related to complications like leukostasis or infiltration, is still unclear. Due to non-adherent and viscoelastic nature of leukemia cells, accurate measurement of their elastic modulus is still a challenging issue. In this study, we adopted ratejump method together with optical tweezers indentation to accurately measure elastic modulus of leukemia cells K562 after phorbol 12-myristate 13-acetate (PMA), all-trans retinoic acid (ATRA), Cytoxan (CTX), and Dexamethasone (DEX) treatment, respectively. We found that compared to control sample, K562 cells treated by PMA showed nearly a threefold increase in elastic modulus. Transwell experiment results suggested that the K562 cells treated with PMA have the lowest migration capability. Besides, it was shown that the cytoskeleton protein gene a-tubulin and vimentin have a significant increase in expression after PMA treatment by qPCR. The results indicate that PMA has a significant influence on protein expression, stiffness, and migration ability of the leukemia cell K562, and may also play an important role in the leukostasis in leukemia.
Estrogen Modulates Epithelial Breast Cancer Cell Mechanics and Cell-to-Cell Contacts
Materials
Excessive estrogen exposure is connected with increased risk of breast cancer and has been shown to promote epithelial-mesenchymal-transition. Malignant cancer cells accumulate changes in cell mechanical and biochemical properties, often leading to cell softening. In this work we have employed atomic force microscopy to probe the influence of estrogen on the viscoelastic properties of MCF-7 breast cancer cells cultured either in normal or hormone free-medium. Estrogen led to a significant softening of the cells in all studied cases, while growing cells in hormone free medium led to an increase in the studied elastic and viscoelastic moduli. In addition, fluorescence microscopy shows that E-cadherin distribution is changed in cells when culturing them under estrogenic conditions. Furthermore, cell-cell contacts seemed to be weakened. These results were supported by AFM imaging showing changes in surfaces roughness, cell-cell contacts and cell height as result of estrogen treatment. T...
Multicellular architecture of malignant breast epithelia influences mechanics
PloS one, 2014
Cell-matrix and cell-cell mechanosensing are important in many cellular processes, particularly for epithelial cells. A crucial question, which remains unexplored, is how the mechanical microenvironment is altered as a result of changes to multicellular tissue structure during cancer progression. In this study, we investigated the influence of the multicellular tissue architecture on mechanical properties of the epithelial component of the mammary acinus. Using creep compression tests on multicellular breast epithelial structures, we found that pre-malignant acini with no lumen (MCF10AT) were significantly stiffer than normal hollow acini (MCF10A) by 60%. This difference depended on structural changes in the pre-malignant acini, as neither single cells nor normal multicellular acini tested before lumen formation exhibited these differences. To understand these differences, we simulated the deformation of the acini with different multicellular architectures and calculated their mecha...
Breast Cancer Cells Adapt Contractile Forces to Overcome Steric Hindrance
Biophysical Journal, 2019
Cell migration through the extracellular matrix (ECM) is governed by the interplay between cell generated propulsion forces, adhesion forces, and resisting forces arising from the steric hindrance of the matrix. Steric hindrance in turn depends on matrix porosity, matrix deformability, cell size, and cell deformability. In this study, we investigate how cells respond to changes in steric hindrance that arise from altered cell mechanical properties. Specifically, we measure traction forces, cell morphology and invasiveness of MDA-MB 231 breast cancer cells in three-dimensional (3-D) collagen gels. To modulate cell mechanical properties, we either decrease nuclear deformability by 2-fold overexpression of the nuclear protein lamin A, or we introduce into the cells stiff polystyrene beads with a diameter larger than the average matrix pore size. Despite this increase of steric hindrance, we find that cell invasion is only marginally inhibited, as measured by the fraction of motile cells and the mean invasion depth. To compensate for increased steric hindrance, cells employ two alternative strategies. Cells with higher nuclear stiffness increase their force polarity, whereas cells with large beads increase their net contractility. Under both conditions, the collagen matrix surrounding the cells stiffens dramatically and carries increased strain energy, suggesting that increased force polarity and increased net contractility are functionally equivalent strategies for overcoming an increased steric hindrance.