文章基本信息

标题：Simulated microgravity inhibits cell focal adhesions leading to reduced melanoma cell proliferation and metastasis via FAK/RhoA-regulated mTORC1 and AMPK pathways
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作者：Xin Tan ; Aizhang Xu ; Tuo Zhao 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：3769
DOI：10.1038/s41598-018-20459-1
语种：English
出版社：Springer Nature
摘要：Simulated microgravity (SMG) was reported to affect tumor cell proliferation and metastasis. However, the underlying mechanism is elusive. In this study, we demonstrate that clinostat-modelled SMG reduces BL6-10 melanoma cell proliferation, adhesion and invasiveness in vitro and decreases tumor lung metastasis in vivo. It down-regulates metastasis-related integrin α6β4, MMP9 and Met72 molecules. SMG significantly reduces formation of focal adhesions and activation of focal adhesion kinase (FAK) and Rho family proteins (RhoA, Rac1 and Cdc42) and of mTORC1 kinase, but activates AMPK and ULK1 kinases. We demonstrate that SMG inhibits NADH induction and glycolysis, but induces mitochondrial biogenesis. Interestingly, administration of a RhoA activator, the cytotoxic necrotizing factor-1 (CNF1) effectively converts SMG-triggered alterations and effects on mitochondria biogenesis or glycolysis. CNF1 also converts the SMG-altered cell proliferation and tumor metastasis. In contrast, mTORC inhibitor, rapamycin, produces opposite responses and mimics SMG-induced effects in cells at normal gravity. Taken together, our observations indicate that SMG inhibits focal adhesions, leading to inhibition of signaling FAK and RhoA, and the mTORC1 pathway, which results in activation of the AMPK pathway and reduced melanoma cell proliferation and metastasis. Overall, our findings shed a new light on effects of microgravity on cell biology and human health.