Abstract 516: Long noncoding RNA NEAT1 promotes lung metastasis of soft tissue sarcoma

Abstract

Abstract Soft tissue sarcomas (STS) are malignant tumors from diverse mesenchymal tissues. About 40% STS patients develop fatal lung metastasis with a median survival of 15 months. The mechanisms driving the development of lung metastasis in sarcoma patients are poorly understood. Therefore, our lab has developed a genetically engineered mouse model (GEMM) of high-grade primary STS with conditional mutations in Kras and Trp53 (KP) where 40% of mice tumors develop lung metastasis. This KP model recapitulates human patients with Undifferentiated Pleomorphic Sarcoma (UPS), one of the most common subtypes of STS diagnosed in adults. RNA sequencing (RNA-Seq) was performed on paired primary and lung metastases in KP mouse sarcomas and determined that the expression of the long non-coding RNA (lncRNA) Neat1 is increased in lung metastases compared to paired primary tumors. Real time PCR (qPCR) in 22 paired KP mouse primary sarcomas and lung metastases further confirmed that Neat1 is significantly upregulated in lung metastases. In addition, RNA-Seq data from 5 pairs of human primary sarcomas and matched lung metastases also showed that NEAT1 levels are increased in lung metastases. Furthermore, NEAT1 RNA in situ hybridization (ISH) on tissue microarrays (TMAs) of human primary UPS and lung metastases determined that the expression of NEAT1 is upregulated in lung metastases. Next, CRISPR/Cas9 technology was applied to delete Neat1 in primary mouse sarcoma cells and loss of expression of Neat1 was confirmed by qPCR and northern blot in knockout (KO) clones. In addition, loss of Neat1 significantly reduced lung metastasis in vivo following tail vein injection of these modified cells into nude mice. To further test that loss of Neat1 reduces lung metastasis in primary sarcoma mouse model, primary tumors with Neat1 deletion are generated in GEMMs using in vivo CRISPR/Cas9 technology and KrasLSL-G12D/+; Trp53Flox/Flox; Neat1-/- (KPN) mouse model. Finally, RNA-Seq and capture hybridization analysis of RNA targets (CHART) are performed to determine mechanisms by which Neat1 regulates lung metastasis. Overall, these results suggest that upregulation of Neat1 promotes lung metastasis of soft tissue sarcoma and NEAT1 is a potential target to prevent or treat lung metastasis in sarcoma patients. Citation Format: Jianguo Huang, Eric Xu, Mohit Sachdeva, Timothy Robinson, Xiaodi Qin, Dadong Zhang, Kouros Owzar, Nalan Gokgoz, Andrew Seto, Irene Andrulis, Jay Wunder, Tomoyo Okada, Samuel Singer, Alexander Lazar, Brian Rubin, David G. Kirsch. Long noncoding RNA NEAT1 promotes lung metastasis of soft tissue sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 516.