ECM Mechanoregulation in Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma is a relatively rare, but devastating tumor, because of the difficulties in providing early diagnosis and effective treatments with conventional chemo- and radiotherapies. Patients usually present pleural effusions that can be used for diagnostic purposes by cytological analysis. This effusion cytology may take weeks or months to establish and has a limited sensitivity (30%-60%). Then, it is becoming increasingly urgent to develop alternative investigative methods to support the diagnosis of mesothelioma at an early stage when this cancer can be treated successfully. To this purpose, mechanobiology provides novel perspectives into the study of tumor onset and progression and new diagnostic tools for the mechanical characterization of tumor tissues. Here, we report a mechanical and biophysical characterization of malignant pleural mesothelioma cells as additional support to the diagnosis of pleural effusions. In particular, we examined a normal mesothelial cell line (Met5A) and two epithelioid mesothelioma cell lines (REN and MPP89), investigating how malignant transformation can influence cellular function like proliferation, cell migration, and cell spreading area with respect to the normal ones. These alterations also correlated with variations in cytoskeletal mechanical properties that, in turn, were measured on substrates mimicking the stiffness of patho-physiological ECM.

X-rays effects on cytoskeleton mechanics of healthy and tumor cells.

Alterations in the cytoskeleton structure are frequently found in several diseases and particularly in cancer cells. It is also through the alterations of the cytoskeleton structure that cancer cells acquire most of their common features such as uncontrolled cell proliferation, cell death evasion, and the gaining of migratory and invasive characteristics. Although radiation therapies currently represent one of the most effective treatments for patients, the effects of X-irradiation on the cytoskeleton architecture are still poorly understood. In this case we investigated the effects, over time of two different doses of X-ray irradiation, on cell cytoskeletons of BALB/c3T3 and Sv40-transformed BALB/c 3T3 cells (SVT2). Biophysical parameters - focal adhesion size, actin bundles organization, and cell mechanical properties - were measured before and after irradiations (1 and 2 Gy) at 24 and 72 h, comparing the cytoskeleton properties of normal and transformed cells. The differences, before and after X-irradiation, were revealed in terms of cell morphology and deformability. Finally, such parameters were correlated to the alterations of cytoskeleton dynamics by evaluating cell adhesion at the level of focal adhesion and cytoskeleton mechanics. X-irradiation modifies the structure and the activity of cell cytoskeleton in a dose-dependent manner. For transformed cells, radiation sensitively increased cell adhesion, as indicated by paxillin-rich focal adhesion, flat morphology, a well-organized actin cytoskeleton, and intracellular mechanics. On the other hand, for normal fibroblasts IR had negligible effects on cytoskeletal and adhesive protein organization. © 2016 Wiley Periodicals, Inc.

Mechanical phenotyping of cells and extracellular matrix as grade and stage markers of lung tumor tissues.

The mechanical cross-talk between cells and the extra-cellular matrix (ECM) regulates the properties, functions and healthiness of the tissues. When this is disturbed it changes the mechanical state of the tissue components, singularly or together, and cancer, along with other diseases, may start and progress. However, the bi-univocal mechanical interplay between cells and the ECM is still not properly understood. In this study we show how a microrheology technique gives us the opportunity to evaluate the mechanics of cells and the ECM at the same time. The mechanical phenotyping was performed on the surgically removed tissues of 10 patients affected by adenocarcinoma of the lung. A correlation between the mechanics and the grade and stage of the tumor was reported and compared to the mechanical characteristics of the healthy tissue. Our findings suggest a sort of asymmetric modification of the mechanical properties of the cells and the extra-cellular matrix in the tumor, being the more compliant cell even though it resides in a stiffer matrix. Overall, the simultaneous mechanical characterization of the tissues constituents (cells and ECM) provided new support for diagnosis and offered alternative points of analysis for cancer mechanobiology. STATEMENT OF SIGNIFICANCE: When the integrity of the mechanical cross-talk between cells and the extra-cellular matrix is disturbed cancer, along with other diseases, may initiate and progress. Here, we show how a new technique gives the opportunity to evaluate the mechanics of cells and the ECM at the same time. It was applied on surgically removed tissues of 10 patients affected by adenocarcinoma of the lung and a correlation between the mechanics and the grade and stage of the tumor was reported and compared to the mechanical characteristics of the healthy tissue.