Abstract
Trichostatin A (TSA) has been demonstrated to exhibit various anticancer effects that influence cell cycle arrest, cell proliferation and apoptosis of cancer cells. A potential association between TSA and endoplasmic reticulum (ER) function has been suggested but its anticancer mechanism involving the induction of ER stress is unknown. p53 has previously been demonstrated to regulate ER function in response to stress but its role involving TSA and ER stress in cancer cells is poorly understood. The current study identified that TSA induced ER stress in wild type (WT) HCT116 human colon cancer cells. Following TSA treatment, the ER stress markers GRP78 and GRP94 significantly increased without hyperacetylation of their promoter regions. The inositol-requiring enzyme 1 α (IRE1α)/X-box binding protein 1 (XBP1) pathway was implicated due to an association of phosphorylated IRE1α and spliced XBP1 with ER stress. However, luciferase reporter assay indicated that splicing events were attenuated in HCT116 TP53(-/-) cells. Furthermore, cell viability and apoptosis were revealed to depend on p53 during TSA treatment. Cell viability increased and the apoptosis rate decreased in HCT116 TP53(-/-) cells compared with WT HCT116 cells undergoing TSA treatment. In conclusion, the current study revealed that TSA may induce ER stress via a p53-dependent mechanism in colon cancer cells. This provides information that may assist the development of treatments that exploit the anticancer function of TSA.