Abstract 5203: Long non-coding RNA H19 as a novel therapeutic target for pancreatic cancer

Abstract

Abstract Long non-coding RNAs (lncRNAs), non-protein coding transcripts longer than 200 nucleotides, have been recently reported to play important roles in carcinogenesis and cancer metastasis through epigenetic regulation. In the present study, we examined the expression levels and roles of lncRNA in pancreatic cancer to elucidate whether lncRNA could be a novel candidate for pancreatic cancer therapy. First, we injected PANC-1 and PK-45H, pancreatic ductal adenocarcinoma cells into the spleens of NOD/Shi-scid, IL-2Rγnull (NOG) mice, and then established novel cell lines from liver and lung metastatic nodules. Microarray analysis revealed that H19, a member of lncRNA, and CTAG1A and CTAG2, cancer-testis antigens, were the most increased RNAs in PANC-lung-1A cells from lung metastasis as compared to the parental cells (82.4, 84.4 and 62.2-fold, respectively). Quantitative RT-PCR (qRT-PCR) confirmed higher levels of H19 mRNA in the metastatic cell lines from PANC-1 and PK-45H cells than in PANC-Skin cells from subcutaneous tumors. H19 is an imprinted non-coding RNA, and the H19 gene produces a 2.3 kb lncRNA during embryogenesis. Its expression is low or non-existent in normal human tissues. H19 is abundantly expressed in liver, breast, endometrial and bladder cancers, but the roles of H19 that have been reported in these cancers are controversial. In six of 10 pancreatic carcinoma cell lines, the H19 levels determined by qRT-PCR were higher than those of immortalized pancreatic ductal epithelial cell lines (HPDE 4 and 6). Established pancreatic cancer cells from liver metastasis of the same patient (PK-45H) showed higher H19 mRNA levels than those from primary tumor (PK-45P). In situ hybridization analysis using branched DNA probe for H19 mRNA showed that H19 was expressed in ductal cells, but not in acinar and islet cells in normal pancreatic tissues. On the other hand, H19 was strongly expressed in pancreatic cancer cells in 6 out of 38 (16%) pancreatic ductal adenocarcinoma tissues. siRNA targeting H19 was transfected to PANC-lung-1A cells to clarify the roles of H19 in the metastatic cells. The cell proliferation rate was not altered in the siRNA transfected metastatic cells, but cell migration, as observed using a Boyden chamber assay, and sphere formation were significantly decreased in the cells. H19 mRNA in PANC-1 cells was more abundantly detected in the spheres than the non-sphere cells. These findings suggest that H19 lncRNA plays important roles in the metastasis and cancer stem cell functions of pancreatic cancer. H19 is a novel candidate as a therapeutic target for pancreatic cancer metastasis. Note: This abstract was not presented at the meeting. Citation Format: Hisashi Yoshimura, Yoko Matsuda, Taeko Suzuki, Zenya Naito, Toshiyuki Ishiwata. Long non-coding RNA H19 as a novel therapeutic target for pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5203. doi:10.1158/1538-7445.AM2014-5203