Tumor Cells in Microgravity

Abstract

The excessive proliferation and metastasis of tumor cells are due to frequent genetic alterations 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 simulations, 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 cancer 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 underline new clues to the tumor initiation, process, diagnosis, and therapy.

Microgravity, Stem Cells, and Cancer: A New Hope for Cancer Treatment

“…Furthermore, EMT is also involved in other steps in the cancer process. Under microgravity, the TGF- β signaling pathway simultaneously inhibits the expression of two EMT-induced genes, snail1 and snail2 , and promotes apoptosis [ 20 , 21 ].…”

Breast Cancer Cells in Microgravity: New Aspects for Cancer Research

“…In addition, s-µ g attenuated the expression of integrin-β1 and integrin-β4 and affected adhesion signaling by decreasing FAK, PYK2, and ILK kinase activity in MCF-7 cells [ 72 ]. Chen [ 90 ] later proposed that both decreased integrin expression and downregulated FA kinase activities are key processes in suppression of breast cancer cell migration under s-µ g . Most recently, Shi et al [ 91 ] performed experiments with MCF-7 cells on an RWV and reported that EMT transcription factors (Snail, Twist, and ZEB1) are also involved in the alteration of cell adhesion properties under s-µ g .…”

Changes in the Surface Expression of Intercellular Adhesion Molecule 3, the Induction of Apoptosis, and the Inhibition of Cell-Cycle Progression of Human Multidrug-Resistant Jurkat/A4 Cells Exposed to a Random Positioning Machine

“…Space experiments are of great value for the study of various physiological characteristics of the human body; health problems; and, in particular, cancer [1][2][3]. Microgravity allows one to explore the molecular and cellular mechanisms of the biological effects on cellular stress and the transformation of normal and tumor cells with a change in gravity [4][5][6].…”

“…Many reports have indicated that simulated microgravity affects cellular morphology, proliferation, apoptosis, invasion, and migration while inhibiting cancerous cell growth and invasion [6][7][8][9][10][11][12][13]. After simulated-microgravity exposure, apoptosis has been observed in glial cells [7], endothelial cells [8], thyroid cancer cells [9], and Jurkat cells [5].…”

“…Recently, in vitro microgravity has been of particular interest as a system for both studying cancer mechanisms and for testing anticancer drugs [6,19,20]. Multicellular spheroids are a model for studying the mechanisms of angiogenesis and pharmacological testing of chemotherapeutic agents [21][22][23].…”