Poster

Influence of mechanical stress and confinement in the development of time dependent resistance to cisplatin

Yasmin Antonelli¹, René Krüger², Nicolás Tobar^1,3, Zhe Wang¹, Lennart Linke¹, Christine Selhuber-Unkel¹, Aldo Leal-Egaña¹

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The tumor microenvironment plays a critical role in disease progression, with mechanical stimuli sensed by cancer cells emerging as key factors in stimulating malignancy, alongside traditional genetic and metabolic hallmarks. In this study, we evaluated the role of the confinement and mechanical stress, in promoting the expression of essential cancer hallmarks observed in vivo by replicating the biomechanical milieu sensed by malignant cells during the early stages of disease.
Using the breast cancer cell line MDA-MB-231 as example, in this work we show that cells immobilized in a semi-degradable hydrogel scaffold exhibited greater resistance to the anticancer drug cisplatin, compared to those cultured in traditional 2D flasks or as 3D suspended spheroids. Cells grown in the hydrogel scaffold displayed a time-dependent resistance, correlating with the mechanical preconditioning in the scaffold, and suggesting that mechanical stress and confinement may tune several mechanisms by which cells become resistant, such as their capability to metabolize and excrete these drugs, to name a few. In contrast, this temporal resistance pattern was absent in cells cultured as 3D spheroids, further supporting the hypothesis that mechanical stimuli actively contribute to cisplatin resistance. To investigate the impact of mechanical stimulation, we conducted a biomechanical characterization of cancer cells grown in our 3D model. This included measuring cell stiffness through nanoindentation, as well as directly assessing stiffness within the 3D environment, using Brillouin microscopy. Preliminary results indicate that cell stiffness increases with extended culture time in the 3D milieu. However, further analyses are required to explore potential correlations between increased cell stiffness and drug resistance, including cytoskeletal alterations and changes in membrane fluidity. To further understand the molecular mechanisms driving this resistance, we performed temporal proteomic analysis to compare protein expression profiles across different culture conditions and examine how these profiles evolve over time. The goal of this approach is to identify pathways that are differentially expressed in distinct growth environments and change as cisplatin resistance develops.
This study offers a novel approach aimed at deepening our understanding of the tumor microenvironment, particularly how mechanical stress and confinement contribute to cell resistance. These insights could provide valuable information for tailoring treatment strategies at different stages of disease progression.