Tumor Cells in Microgravity

Abstract

The excessive proliferation and metastasis of tumor cells are due to frequent genetic alter- ations and subsequent stimulation of abnormal signal transduction pathways. Inventing and improving novel therapeutic strategies are critically needed. However, it remains unknown which of these pathways is essential to tumor initiation and progression. A weightless environment on Earth is a rare phenomenon, achieved using various simu- lations, but brings about changes of internal cellular structure and interactions among cells not normally seen under normal terrestrial gravitational conditions. For this reason, spaceflight experiments are of great value for cell biology research in general and for can- cer research in particular. Many experiments indicate that microgravity, more so actual spaceflight as opposed to simulations, induces changes in the expression and secretion of genes as well as proteins involved in cancer cell proliferation, metastasis, and survival, shifting the cells toward a less aggressive phenotype. Therefore, studies on the biological features and gene expression of tumors cells under microgravity conditions may under- line new clues to the tumor initiation, process, diagnosis, and therapy.