Mechanical regulation of cell biology: investigating the impact of uniaxial 1hz cyclic stress on osteosarcoma cells

In the past decade, there has been a growing recognition of the significant impact of mechanobiology on the progression and metastasis of solid tumors, particularly in the context of osteosarcoma. Despite advancements in curative approaches, survival rates for osteosarcoma, the most prevalent form of primary bone cancer, have plateaued, posing new therapeutic challenges. Recent studies have revealed the ability of osteosarcoma cells to modulate malignancy in response to extracellular stimuli. This study aims to elucidate the biological responses induced by selected uniaxial cyclic stretching (1Hz, 24-hour cycle, 0.5% strain) in two human osteosarcoma cell lines: the moderately aggressive SAOS-2 and the highly aggressive U-2 OS. Employing uniaxial-stretching technology, we explore morpho-functional changes and mechanosensitive molecules involved in mechanotransduction in these cell models in vitro. Our findings reveal that cyclic stretching induces significant morphological and phenotypic changes in osteosarcoma cells, indicating increased aggressiveness in both cell lines. Through advanced imaging techniques such as atomic force microscopy (AFM), confocal, and fluorescence microscopy, we demonstrate that 1Hz-24h cyclic stimulus increases nuclear surface area, disrupting the nuclearcytoplasmic ratio (N/C) a crucial morphological indicator of malignancy. Cellbased biochemical assays associate these changes with alterations in adhesiveness and migration, critical properties influencing the metastatic process in osteosarcoma. Intriguingly, while U-2 OS cells exhibit increased resistance, SAOS-2 cells become more susceptible to doxorubicin-induced cytotoxicity following mechanical stimulation, potentially due to dysregulation of energy metabolism and oxidative redox state, as suggested by LC-MS-based metabolomic data. 10 Furthermore, our investigation identifies the role of TRPV1 as a major contributor and TRPA1 as a minor contributor among the TRP family mechanosensitive channels in mediating morphological and functional changes within osteosarcoma cells in response to a 1Hz-24h strain. These findings offer valuable insights into the cellular mechanisms underlying osteosarcoma cells' response to mechanical stimuli. In conclusion, this study underscores the critical role of mechanobiology in osteosarcoma progression and provides a foundation for future exploration in uncovering mechanically induced changes in cell morphology and phenotype, thereby opening new avenues in cancer research.