Abstract 160: ZFAS1, long non-coding RNA with significance in colorectal cancer
Authors: Thorenoor Nithyananda , Vychytilova Petra , Mlcochova Jitka , Hombach Sonja , Kretz Markus , Sana Jiri , Slaby Ondrej 
Published: August 2015

Abstract
Introduction: Colorectal cancer (CRC) is one of the most common cancers in the world. However, the existence of multiple known carcinogens and varying genetic backgrounds makes it difficult to determine which factors are most important in the development of CRC. Therefore, the identification of a bona fide molecule involved in progression of CRC has been greatly sought after. Long noncoding RNAs (lncRNA) are emerging as key molecules in human cancer, and some of them were shown to have potential for cancer diagnosis and prognosis. ZFAS1, an lncRNA, has been recently revealed involving in human breast cancer as putative tumor suppressor. However, whether ZFAS1 is involved in CRC pathogenesis or could serve as novel biomarker in CRC is unknown.
Patients and methods: By use of high throughput technology we identified ZFAS1 as one of the highly up-regulated lncRNA in CRC tissue. Thus, aim of the current study was to explore the correlation between ZFAS1 expression and progression of CRC and its clinical significance. The expression levels of ZFAS1 were determined by quantitative real-time PCR and in selected cases by Northern blot and evaluated in larger cohort (120 cases) of CRC tissues and cell lines (HCT116, DLD1, SW620), which were compared to paired adjacent normal tissues or normal colonic cell lines. The potential relationship between ZFAS1 levels in tumor tissues and the clinicopathological features of CRC was also evaluated. Further, we assessed whether ZFAS1 influences cell proliferation, apoptosis, cell cycle and migration in-vitro. The different isoforms of ZFAS1 were determined by RACE-PCR and protein interacting partners of ZFAS1 were analyzed by pull-down experiment and mass spectrometry. The identified candidate proteins were evaluated by RNA-IP.
Results: Our results showed that ZFAS1 expression in CRC tissues and cell lines were significantly increased compared with matched normal tissues (p &lt; 0.0001). In addition, siRNA-mediated knockdown of ZFAS1 expression significantly influenced the proliferation of CRC cells (p &lt; 0.05) Interestingly, ZFAS1 intronically hosts three C/D box snoRNAs (SNORDs): SNORD12, 12B, and 12B. The general assumption that noncoding SNORD-host transcripts function only as vehicles to generate snoRNAs, knockdown of ZFAS1 in a CRC cell lines resulted in decreased cellular proliferation, while not substantially altering the levels of the SNORDs.
Conclusion: Our current study demonstrates that ZFAS1 levels are increased in CRC tissue and influences significantly proliferation of CRC cells in vitro, indicating its potential oncogenic functioning in CRC.
The work has been supported by Project CZ.1.07/2.3.00/30.0037, and IGA MZCR NT13549-4/2012, NT13860-4/2012.
Citation Format: Nithyananda Thorenoor, Petra Vychytilova, Jitka Mlcochova, Sonja Hombach, Markus Kretz, Jiri Sana, Ondrej Slaby. ZFAS1, long non-coding RNA with significance in colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 160. doi:10.1158/1538-7445.AM2015-160