The Effects Of Simulated Microgravity On Centrosome And BUB1 In Human Osteosarcoma Cells

The main factors of the space environment which can influence human bodies are ionizing radiation and sustaining microgravity. Many studies showed that space microgravity can cause physiological and pathological changes to astronauts'bodies. To investigate the damages of human cells under microgravity effects, here the changes of microtubule cytoskeleton, centrosomes and spindle checkpoint protein BUB1 in human osteosarcoma cell lines (U-2 OS, MG-63 and Saos-2) were analyzed under simulated microgravity effect generating by clinostat. In this study, the results showed that under the simulated microgravity effect for 72 hours the microtubules cytoskeleton in human osteosarcoma cell lines were in disorder. The rates of multipolar spindle in human osteosarcoma cell U-2 OS increased under simulated microgravity effect and became higher with simulated microgravity times lengthened. It was detected that on polars of bipolar and abnormal multipolar spindle in human osteosarcoma cell lines U-2 OS, MG-63 and Saos-2 there were centrosomes existed by immunofuorescence staining of Centrin-2; but the expression of centrosomes componentγ-tubulin didn't showed significantly upregulated in U-2 OS and MG-63 cells under simulated microgravity effect by Western Blot analysis, prompting that the appearance of extra centrosome under simulated microgravity effect was not due to extra centrosome replication occured. The real time quantitative reverse transcription PCR (qRT-PCR) analysis and Western Blot analysis showed that the expression of the spindle assembly checkpoint protein BUB1 in U-2 OS and MG-63 cells upregulated both in mRNA level and protein level under simulated microgravity effect. These results with respect to the change of centrosome and checkpoint protein BUB1 under of simulated microgravity effect research has not been reported in space biology studies, so it may be a reference for space biology research in related areas.