Abstract 3484: A long non-coding RNA, H19, as a novel therapeutic target for pancreatic cancer metastasis

Abstract

Abstract Long non-coding RNAs (lncRNAs) comprise mRNA-like transcripts longer than 200 ribonucleotides and lack significant open reading frames. Recently, long non-coding RNAs have been reported to play important roles in epigenetic regulation, and acts on precursors or inhibitor of micro RNA. In our previous studies, we injected PANC-1, human pancreatic cancer cells into the spleens of NOG mice, and established a lung metastasis-derived cell line from lung metastatic nodules. Lung metastasis derived pancreatic cells had a high metastatic ability to liver and lungs compared with the parental cells (Matsuda et al., Am J Pathol, 2014). To examine the different gene expressions between the lung metastasis derived cells and parental cells, we performed a DNA microarray analysis. We found that 11 genes were expressed at greater than 10-fold levels in lung metastasis derived cancer cells compared to their parental cells. H19 showed an 82.4-fold increase in expression levels, and it was the second most increased and the only non-protein coding gene in the 11 genes. H19 is an imprinted lncRNA transcribed exclusively from the maternal allele and H19 gene produces a 2.3 kilo base pair long non-coding RNA. Two microRNAs, miR-675-3p and miR-675-5p are embedded in the exon1 of H19 and these miRNAs are reported to correlate with cell proliferation. H19 is an oncofetal RNA expressed in developing embryos and in tumors including bladder, breast, gastric, pancreatic, hepatocellular, and prostate cancers. Studies have shown that H19 enhances cancer invasion and metastasis; however, its role in cancer remains debatable. We examined the roles of H19 in pancreatic cancer growth and metastasis. Quantitative RT-PCR analysis using human pancreatic cancer tissues showed that H19 was more highly expressed in cancer tissues than the adjacent normal tissues in 11 of 18 cases. Branched DNA in situ hybridization analysis using tissue microarrays showed that H19 was detected in 17% (23/139) of invasive ductal carcinomas, and its expression positively correlated with higher histological tumor grades (P < 0.0001). H19 was expressed in 9 pancreatic cancer cell lines at various levels. Overexpression of H19 in PANC-1 cells induced higher motilities, whereas H19 inhibition using shRNA and siRNA showed opposite results; however, cell growth rates were unaffected in vitro. Expression levels of miR-675-3p and miR-675-5p altered as similar to the H19 levels in both H19 increased PANC-1 cells and H19 decreased cells. Tail vein injection of H19 shRNA vector-transfected PANC-1 cells markedly inhibited metastasis in the liver and lungs of immunodeficient mice. These findings suggest that H19 plays an important role in pancreatic cancer metastasis and H19 is a novel therapeutic target for metastasis of pancreatic cancer. Citation Format: Toshiyuki Ishiwata, Hisashi Yoshimura, Yoko Matsuda, Naoshi Ishikawa, Kaiyo Takubo, Tomio Arai, Junko Aida. A long non-coding RNA, H19, as a novel therapeutic target for pancreatic cancer metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3484. doi:10.1158/1538-7445.AM2017-3484