Effects of Simulated Microgravity on Colorectal Cancer Organoids Growth and Drug Response

Cellular and molecular dynamics of human cells are constantly affected by gravity. Alteration of the gravitational force disturbs the cellular equilibrium, which might modify physiological and molecular characteristics. Nevertheless, biological responses of cancer cells to reduced gravitational force remains obscure. Here, we aimed to comprehend not only transcriptomic patterns but drug responses of colorectal cancer (CRC) under simulated microgravity. We established four organoids directly from CRC patients, and organoids cultured in 3D clinostat were subjected to genome wide expression profiling and drug library screening. Our observations revealed changes in cell morphology and an increase in cell viability under simulated microgravity compared to their static controls. Transcriptomic analysis highlighted a significant dysregulation in the TBC1D3 family of genes. The upregulation of cell proliferation observed under simulated microgravity conditions was further supported by enriched cell cycle processes, as evidenced by the functional clustering of mRNA expressions using cancer hallmark and gene ontology terms. Our drug screening results indicated an enhanced response rate to 5-FU under conditions of simulated microgravity, suggesting potential implications for cancer treatment strategies in simulated microgravity. Four colorectal cancer (CRC) organoids were cultured under microgravity using clinostat and compared the organoids cultured in normal gravity. In the operational context of the 3D clinostat, certain forces such as Coriolis, radial, and frictional forces were deemed negligible. This assessment is based on the relatively minimal angular velocities achieved by the two axes of the clinostat, specifically, the inner frame rotating at 0.683 revolutions per minute (rpm) and the outer frame at 0.913 rpm. The transcriptomic landscape of four CRC organoids cultured under microgravity was analyzed using RNA-seq.