CHANGES IN GENE EXPRESSION OF HepG2 CELLS EXPOSED TO MICROGRAVITY

Abstract

The impact of microgravity and space radiation has been previously studied on certain cell lines, and the findings indicated there were cytological and other alterations of the cells as well as changes in gene expression profiles. The effects of microgravity reported include reduction in growth activation and decline in growth rate in the total cell population (Tipton et al, 1996), increase in apoptosis rate (Lewis et al., 1998), cell cycle changes (Arbogast et al., 1999), and chromosomal damage (Hammond et al. 1999). Other studies have also reported that microgravity induced changes in the cell cytoskeleton (Lewis et al., 1998) and increased expression of various key transcription factors in the hepatocellular carcinoma cell line (HepG2) grown under simulated microgravity conditions (Khaoutov et al., 2001). However, no study has been conducted on HepG2 in real spaceflight. This study was one of the space experiments flown to the ISS in October 2007 as part of Malaysia’s Space Science Programme. We took this opportunity to send the HepG2 cell line and study the changes in gene expression of the cells in microgravity at T0 and T72 in comparison to the pre-launched ground controls (T-96)