To explore the relationship between UPR and autophagy in intestinal epithelial cells, we investigated whether autophagy was induced by endoplasmic reticulum (ER) stress in colon cancer cell lines. We demonstrated that autophagy was induced by ER stress in HT29, SW480, and Caco-2 cells. In these cells, inositol-requiring enzyme1 alpha (IRE1 alpha) and C/EBP homologous protein (CHOP) were involved in the ER stress-autophagy pathway, and CHOP was a regulator of IRE1 alpha, protein expression. Our findings suggest that CHOP promotes IRE1 alpha and autophagy especially in ER stress conditions. This study will provide important insights into the disclosure of the ER stress-autophagy pathway. (C) 2014 Elsevier Inc. All rights reserved.