Radiotherapy is one of the main treatments for clinical cancer therapy. However, 
its application was limited due to lack of radiosensitivity in some cancers. 
Trichostatin A (TSA) is a classic histone deacetylases inhibitor (HDACi) that 
specifically inhibits the biochemical functions of HDAC and is demonstrated to 
be an active anticancer drug. However, whether it could sensitize colon cancer 
to radiation is not clear. Our results showed that TSA enhanced the 
radiosensitivity of colon cancer cells as determined by CCK-8 and clonogenic 
survival assay. Moreover, apoptotic cell death induced by radiation was enhanced 
by TSA treatment. Additionally, TSA also induced autophagic response in colon 
cancer cells, while autophagy inhibition led to cell apoptosis and enhanced the 
radiosensitivity of colon cancer cells. Our data suggested that inhibition of 
cytoprotective autophagy sensitizes cancer cell to radiation, which might be 
further investigated for clinical cancer radiotherapy.