Viscoelastic Liquid Matrix with Faster Bulk Relaxation Time Reinforces the Cell Cycle Arrest Induction of the Breast Cancer Cells via Oxidative Stress

Beyond stiffness: deciphering the role of viscoelasticity in cancer evolution and treatment response

There is increasing evidence that cancer progression is linked to tissue viscoelasticity, which challenges the commonly accepted notion that stiffness is the main mechanical hallmark of cancer. However, this new insight has not reached widespread clinical use, as most clinical trials focus on the application of tissue elasticity and stiffness in diagnostic, therapeutic, and surgical planning. Therefore, there is a need to advance the fundamental understanding of the effect of viscoelasticity on cancer progression, to develop novel mechanical biomarkers of clinical significance. Tissue viscoelasticity is largely determined by the extracellular matrix (ECM), which can be simulatedin vitrousing hydrogel-based platforms. Since the mechanical properties of hydrogels can be easily adjusted by changing parameters such as molecular weight and crosslinking type, they provide a platform to systematically study the relationship between ECM viscoelasticity and cancer progression. This review begins with an overview of cancer viscoelasticity, describing how tumor cells interact with biophysical signals in their environment, how they contribute to tumor viscoelasticity, and how this translates into cancer progression. Next, an overview of clinical trials focused on measuring biomechanical properties of tumors is presented, highlighting the biomechanical properties utilized for cancer diagnosis and monitoring. Finally, this review examines the use of biofabricated tumor models for studying the impact of ECM viscoelasticity on cancer behavior and progression and it explores potential avenues for future research on the production of more sophisticated and biomimetic tumor models, as well as their mechanical evaluation.

Outlook and opportunities for engineered environments of breast cancer dormancy

Dormant, disseminated breast cancer cells resist treatment and may relapse into malignant metastases after decades of quiescence. Identifying how and why these dormant breast cancer cells are triggered into outgrowth is a key unsolved step in treating latent, metastatic breast cancer. However, our understanding of breast cancer dormancy in vivo is limited by technical challenges and ethical concerns with triggering the activation of dormant breast cancer. In vitro models avoid many of these challenges by simulating breast cancer dormancy and activation in well-controlled, bench-top conditions, creating opportunities for fundamental insights into breast cancer biology that complement what can be achieved through animal and clinical studies. In this review, we address clinical and preclinical approaches to treating breast cancer dormancy, how precisely controlled artificial environments reveal key interactions that regulate breast cancer dormancy, and how future generations of biomaterials could answer further questions about breast cancer dormancy.

Special Issue "Role of Apoptosis and Cellular Senescence in Cancer and Aging"

The intention of this Special Issue is to elucidate the role of apoptosis and cellular senescence in different pathological processes, such as cancer and aging [...].

Effects of matrix viscoelasticity on cell-matrix interaction, actin cytoskeleton organization, and apoptosis of osteosarcoma MG-63 cells

Many recent reports have shown the effects of viscoelasticity of the extracellular matrix on the spreading, migration, proliferation, survival and cell-matrix interaction of mesenchymal stem cells and normal cells. However, the effect of matrix viscoelasticity on the behavior of tumor cells is still in the state of preliminary exploration. To this aim, we prepared a viscoelastic hydrogel matrix with a storage modulus of about 2 kPa and a loss modulus adjustable from 0 to 600 Pa, through adding linear alginate and regulating the compactness of a polyacrylamide covalent network. Overall, the addition of viscous components inhibited the apoptosis of osteosarcoma MG-63 cells, while it promoted their spreading and proliferation and in particular led to a well-developed cytoskeleton organization. However, with the increase of the viscous fraction, this trend was reversed, and the apoptosis of MG-63 cells gradually increased with gradually decreased spreading and proliferation, accompanied by a surprising manner change of the cytoskeleton from fusiform cells dominated by focal adhesion to dendritic cells dominated by pseudopodia. Besides the upregulation of MAPK, Ras, Rap1 and PI3K-Akt pathways commonly involved in mechanotransduction, the upregulation of the Wnt pathway and inhibited endoplasmic reticulum stress-mediated apoptosis were observed for the viscous matrix with a low loss modulus. The high viscosity matrix showed additional involvement of Hippo and NF-kappa B signaling pathways related to the cell-matrix interaction, with downregulation of the endoplasmic reticulum stress pathway and upregulation related to mitochondrial organization. Our study would provide insight into the effect of viscosity on fundamental behaviors of tumor cells and might have important implications in designing antitumor materials.