Activating enhancer-binding protein-2α induces cyclooxygenase-2 expression and promotes nasopharyngeal carcinoma growth
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Dingbo Shi1,*, Xiangsheng Xiao1,*, Yun Tian1,*, Lijun Qin3, Fangyun Xie1, Rui Sun1, Jingshu Wang1, Wenbin Li1, Tianze Liu1, Yao Xiao2, Wendan Yu2, Wei Guo2, Yuqing Xiong1, Huijuan Qiu1, Tiebang Kang1, Wenlin Huang1,4, Chong Zhao1 and Wuguo Deng1,4
1 Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, China
2 Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
3 Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
4 State Key Laboratory of Targeted Drug for Tumors of Guangdong Province, Guangzhou Double Bioproduct Inc., Guangzhou, China
* These authors contributed equally to this manuscript
Chong Zhao, email:
Wuguo Deng, email:
Keywords: AP-2α, COX-2, p300, nasopharyngeal carcinoma
Received: November 07, 2014 Accepted: December 26, 2014 Published: December 31, 2014
Activating enhancer-binding protein-2α (AP-2α) regulates the expression of many cancer-related genes. Here, we demonstrated a novel mechanism by which AP-2α up-regulated cyclooxygenase-2 (COX-2) expression to promote the growth of nasopharyngeal carcinomas (NPCs). High expression of AP-2α in NPC cell lines and tumor tissues from NPC patients was detected and significantly correlated with COX-2 expression. Overexpression of AP-2α and COX-2 in tumor tissues was associated with advanced tumor stage, clinical progression, and short survival of patients with NPCs. Knockdown of AP-2α by siRNA markedly inhibited COX-2 expression and PGE2 production in NPC cells. Exogenous expression of AP-2α up-regulated the COX-2 and PGE2. Knockdown of AP-2α also significantly suppressed cell proliferation in NPC cells in vitro and tumor growth in a NPC xenograft mouse model. Moreover, we found that p300 played an important role in the AP-2α/COX-2 pathway. AP-2α could co-localize and interact with p300 in NPC cells. Overexpression of the p300, but not its histone acetyltransferase (HAT) domain deletion mutant, promoted the acetylation of AP-2α and its binding on the COX-2 promoter, thereby up-regulated COX-2 expression. Our results indicate that AP-2α activates COX-2 expression to promote NPC growth and suggest that the AP-2α/COX-2 signaling is a potential therapeutic target for NPC treatment.
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