Chemoresistance remains a major problem in the treatment of gastric cancer patients, leading to the serious limitation of efficacy of chemotherapeutic regime. However, the underlying mechanism remains largely unknown. In our present study, we for the first time found that knock down of KDM3A can promote apoptosis induced by chemoreagent Cisplatin and Paclitaxel through p53. Mechanistically, through promoting p53 binding to the promoter of PUMA. However, knock down of KDM3A as such doesn't affect p53 level. In addition, KDM3A can interact with p53K372me1 in protein protein interaction fashion, leading to the inactivation of p53, may eventually leading to chemoresistance of gastric cancer. (C) 2015 Elsevier Inc. All rights reserved.