KMT2C mutations in diffuse type gastric adenocarcinoma promote epithelial-to-mesenchymal transition

Soo-Jeong Cho, Changhwan Yoon, Jun-Ho Lee, Kevin K Chang, Jian-xian Lin, Young Ho Kim, Myeong-Cherl Kook, Bülent A. Aksoy, Do Joong Park, Hassan Ashktorab, Duane Smoot, Nikolaus Schultz (+1 others)
2018 Clinical Cancer Research  
Purpose: Lauren diffuse-type gastric adenocarcinomas (DGAs) are generally genomically stable. We identified lysine (K)-specific methyltransferase 2C (KMT2C) as a frequently mutated gene and examined its role in DGA progression. Experimental Design: We performed whole exome sequencing on tumor samples of 27 patients with DGA who underwent gastrectomy. Lysine (K)-specific methyltransferase 2C (KMT2C) was analyzed in DGA cell lines and in patient tumors. Results: KMT2C was the most frequently
more » ... ost frequently mutated gene (11 of 27 tumors [41%]). KMT2C expression by immunohistochemistry in tumors from 135 patients with DGA undergoing gastrectomy inversely correlated with more advanced tumor stage (P ¼ 0.023) and worse overall survival (P ¼ 0.017). KMT2C shRNA knockdown in nontransformed HFE-145 gastric epithelial cells promoted epithelial-to-mesenchymal transition (EMT) as demonstrated by increased expression of EMT-related proteins N-cadherin and Slug. Migration and invasion in gastric epithelial cells following KMT2C knockdown increased by 47-to 88fold. In the DGA cell lines MKN-45 and SNU-668, which have lost KMT2C expression, KMT2C re-expression decreased expression of EMT-related proteins, reduced cell migration by 52% to 60%, and reduced cell invasion by 50% to 74%. Flank xenografts derived from KMT2C-expressing DGA organoids, compared with wild-type organoids, grew more slowly and lost their infiltrative leading edge. EMT can lead to the acquisition of cancer stem cell (CSC) phenotypes. KMT2C re-expression in DGA cell lines reduced spheroid formation by 77% to 78% and reversed CSC resistance to chemotherapy via promotion of DNA damage and apoptosis. Conclusions: KMT2C is frequently mutated in certain populations with DGA. KMT2C loss in DGA promotes EMT and is associated with worse overall survival. Clin Cancer Res; 24(24); 6556-69. Ó2018 AACR. Analysis and interpretation of data (e.g., statistical analysis, biostatistics, computational analysis):
doi:10.1158/1078-0432.ccr-17-1679 pmid:30108106 fatcat:eiufmgso4jclnistt5ihxw4ffy