P-015 - HOTAIR can determine the proliferation and invasiveness of gastrointestinal stromal tumor

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics GIST
Translational Research
Presenter N.K. Lee
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors N.K. Lee1, S.K. Lee1, J.H. Lee1, W.K. Kim2, S. Yun3, C.H. Park1, Y.Y. Choi1, H. Kim3
  • 1Yonsei University College of Medicine, Seoul/KR
  • 2Department of Internal Medicine Department of Pathology, Seoul/KR
  • 3Institute of Gastroenterology Department of Internal Medicine Department of Pathology, Seoul/KR

Abstract

Introduction

Long non-coding RNAs (lncRNAs) are recently known to play a crucial role in initiation and metastasis of tumor. We reported that HOX antisense intergenic RNA (HOTAIR) inhibit the apoptosis and promote invasion and migration of gastric cancer cell lines. Here we investigate the effect of HOTAIR on the malignant potentials of gastrointestinal stromal tumor.

Methods

HOTAIR expression was determined by qRT-PCR in GISTs cells and fresh frozen tissues, which were surgically resected from patient with gastric GIST. Total RNA extraction was conducted using TRizol and the qRT-PCR was carried out with SYBR green method. Down regulation of HOTAIR was accomplished with two different siRNAs. Cell proliferation by HOTAIR knockdown was measured through MTS assay. To dissect cell death, apoptosis and cell cycle arrest using PI/Annexin V staining were analyzed on flow cytometry. Biologic marker including EMT, apoptosis, and cell cycles were tested on western blot. Transwell matrigel invasion assay was performed to analyze metastasis after HOTAIR silencing.

Results

The expression of HOTAIR was relatively higher in the high-risk malignancy subgroup compared to the low-risk subgroup. HOTAIR silencing by two different siRNAs leads to significant decrease in cell invasion of GIST-T1 and GIST882. Knockdown of HOTAIR decreased the expression of mesenchymal markers including snail, vimentin and zeb1. The cell proliferation Of GIST-T1 and GIST882 after treatment siHOTAIR was significantly decreased. Apoptotic profiling of GIST-T1 and GIST882 by siHOTAIR revealed that significantly increased expression of Cytochrome C, PARP and cleaved PARP. Inhibition of HOTAIR in GIST-T1 induced cell cycle arrest in G2/M and this cell cycle regulatory checkpoint related markers including P21 and P53 were shown increased expression on western blot. In particular, subG1 by siHOTAIR was statistically increased in GIST882 and this finding led to differential expression of pro and anti-apoptotic markers.

Conclusion

Malignant potentials of GIST were related with the expression of HOTAIR, so HOTAIR can be a biomarker or therapeutic target for GIST.