A natural small molecule, catechol, induces c-Myc degradation by directly targeting ERK2 in lung cancer.

// Do Young Lim 1 , Seung Ho Shin 1, 2 , Mee-Hyun Lee 1, 3 , Margarita Malakhova 1 , Igor Kurinov 4 , Qiong Wu 3, 5 , Jinglong Xu 5, 7 , Yanan Jiang 5, 7 , Ziming Dong 5, 7 , Kangdong Liu 3, 5, 6, 7 , Kun Yeong Lee 1 , Ki Beom Bae 1 , Bu Young Choi 8 , Yibin Deng 1 , Ann Bode 1 , Zigang Dong 1, 3, 5, 6, 7 1 The Hormel Institute, University of Minnesota, MN, USA 2 Program in Biomedical Informatics and Computational Biology, University of Minnesota, Minneapolis, MN, USA 3 The China-US (Henan) Cancer Institute, Zhengzhou, Henan, China 4 Cornell University, NE-CAT, Argonne, IL, USA 5 The Pathophysiology Department, The School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Hunan, China 6 The Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou, Henan, China 7 The Collaborative Innovation Center of Henan Province for Cancer Chemoprevention, Zhengzhou, China 8 Pharmaceutical Science and Engineering, School of Convergence Bioscience and Technology, Seowon University, Cheongju, Chungbuk, South Korea Correspondence to: Zigang Dong, email: zgdong@hi.umn.edu Keywords: catechol, lung cancer, ERK2, c-Myc, natural compound Received: January 06, 2016      Accepted: April 10, 2016      Published: May 07, 2016 ABSTRACT Various carcinogens induce EGFR/RAS/MAPK signaling, which is critical in the development of lung cancer. In particular, constitutive activation of extracellular signal-regulated kinase 2 (ERK2) is observed in many lung cancer patients, and therefore developing compounds capable of targeting ERK2 in lung carcinogenesis could be beneficial. We examined the therapeutic effect of catechol in lung cancer treatment. Catechol suppressed anchorage-independent growth of murine KP2 and human H460 lung cancer cell lines in a dose-dependent manner. Catechol inhibited ERK2 kinase activity in vitro , and its direct binding to the ERK2 active site was confirmed by X-ray crystallography. Phosphorylation of c-Myc, a substrate of ERK2, was decreased in catechol-treated lung cancer cells and resulted in reduced protein stability and subsequent down-regulation of total c-Myc. Treatment with catechol induced G1 phase arrest in lung cancer cells and decreased protein expression related to G1-S progression. In addition, we showed that catechol inhibited the growth of both allograft and xenograft lung cancer tumors in vivo . In summary, catechol exerted inhibitory effects on the ERK2/c-Myc signaling axis to reduce lung cancer tumor growth in vitro and in vivo , including a preclinical patient-derived xenograft (PDX) model. These findings suggest that catechol, a natural small molecule, possesses potential as a novel therapeutic agent against lung carcinogenesis in future clinical approaches.