Downregulation of HuR Inhibits the Progression of Esophageal Cancer through Interleukin-18

다국어 초록 (Multilingual Abstract)

Purpose The purpose of this study was to investigate the effect of human antigen R (HuR) downregulation and the potential target genes of HuR on the progression of esophageal squamous cell carcinoma (ESCC).
Materials and Methods In this study, a proteomics assay was used to detect the expression of proteins after HuR downregulation, and a luciferase assay was used to detect the potential presence of a HuR binding site on the 3’-untranslated region (3'-UTR) of interleukin 18 (IL-18). In addition, colony formation assay, MTT, EdU incorporation assay, Western blot, flow cytometry, immunohistochemistry, transwell invasion assay, and wound healing assay were used.
Results In the present study, we found that the expression of both HuR protein and mRNA levels were higher in tumor tissues than in the adjacent tissues. HuR downregulation significantly suppressed cell proliferation. In addition, the metastasis of esophageal cancer cells was inhibited, while the expression of E-cadherin was increased and the expression of matrix metalloproteinase (MMP) 2, MMP9, and vimentin was decreased after HuR knockdown.
Moreover, silencing of HuR disturbed the cell cycle of ESCC cells mainly by inducing G1 arrest. Furthermore, proteomics analysis showed that downregulation of HuR in TE-1 cells resulted in 100 upregulated and 122 downregulated proteins, including IL-18 as a significantly upregulated protein. The expression of IL-18 was inversely regulated by HuR. IL-18 expression was decreased in ESCC tissues, and exogenous IL-18 significantly inhibited the proliferation and metastasis of ESCC cells. The 3'-UTR of IL-18 harbored a HuR binding site, as shown by an in vitro luciferase assay.
Conclusion HuR plays an important role in the progression of esophageal carcinoma by targeting IL-18, which may be a potential therapeutic target for the treatment of ESCC.

참고문헌 (Reference)

1 Danilin S, "von Hippel-Lindau tumor suppressor genedependent mRNA stabilization of the survival factor parathyroid hormone-related protein in human renal cell carcinoma by the RNA-binding protein HuR" 30 : 387-396, 2009

2 Williams TK, "pp32 (ANP32A) expression inhibits pancreatic cancer cell growth and induces gemcitabine resistance by disrupting HuR binding to mRNAs" 5 : e15455-, 2010

3 Liu P, "Upregulation of PAX2 promotes the metastasis of esophageal cancer through interleukin-5" 35 : 740-754, 2015

4 Zotti T, "The emerging role of TRAF7 in tumor development" 232 : 1233-1238, 2017

5 Zhao J, "TIP30 induces apoptosis under oxidative stress through stabilization of p53 messenger RNA in human hepatocellular carcinoma" 68 : 4133-4141, 2008

6 Chen M, "Systematic review and meta-analysis of tumor biomarkers in predicting prognosis in esophageal cancer" 13 : 539-, 2013

7 Zhang W, "RNA-binding protein HuR regulates nuclear import of protein" 129 : 4025-4033, 2016

8 Heinonen M, "Prognostic role of HuR in hereditary breast cancer" 13 : 6959-6963, 2007

9 Li K, "Leptin promotes breast cancer cell migration and invasion via IL-18 expression and secretion" 48 : 2479-2487, 2016

10 Carrascal MT, "Interleukin-18 binding protein reduces b16 melanoma hepatic metastasis by neutralizing adhesiveness and growth factors of sinusoidal endothelium" 63 : 491-497, 2003

11 Chu PC, "Insulin-like growth factor-I receptor is suppressed through transcriptional repression and mRNA destabilization by a novel energy restriction-mimetic agent" 34 : 2694-2705, 2013

12 Markowitz GJ, "Inflammation-dependent IL18 signaling restricts hepatocellular carcinoma growth by enhancing the accumulation and activity of tumor-infiltrating lymphocytes" 76 : 2394-2405, 2016

13 Ott CA, "Induction of exportin-5 expression during melanoma development supports the cellular behavior of human malignant melanoma cells" 7 : 62292-62304, 2016

14 Tong YS, "Identification of the long non-coding RNA POU3F3 in plasma as a novel biomarker for diagnosis of esophageal squamous cell carcinoma" 14 : 3-, 2015

15 Ko CY, "IL-18-induced interaction between IMP3 and HuR contributes to COX-2 mRNA stabilization in acute myeloid leukemia" 99 : 131-141, 2016

16 Yuan Z, "HuR, a key post-transcriptional regulator, and its implication in progression of breast cancer" 25 : 1331-1340, 2010

17 Kundu P, "HuR protein attenuates miRNA-mediated repression by promoting miRISC dissociation from the target RNA" 40 : 5088-5100, 2012

18 Leijon H, "HuR in pheochromocytomas and paragangliomas: overexpression in verified malignant tumors" 124 : 757-763, 2016

19 Romeo C, "HuR contributes to TRAIL resistance by restricting death receptor 4 expression in pancreatic cancer cells" 14 : 599-611, 2016

20 Brennan CM, "HuR and mRNA stability" 58 : 266-277, 2001

21 Wu C, "Genomewide association analyses of esophageal squamous cell carcinoma in Chinese identify multiple susceptibility loci and gene-environment interactions" 44 : 1090-1097, 2012

22 Muralidharan R, "Folate receptor-targeted nanoparticle delivery of HuR-RNAi suppresses lung cancer cell proliferation and migration" 14 : 47-, 2016

23 Denkert C, "Expression of the ELAV-like protein HuR in human colon cancer: association with tumor stage and cyclooxygenase-2" 19 : 1261-1269, 2006

24 Ge J, "Essential roles of RNA-binding protein HuR in activation of hepatic stellate cells induced by transforming growth factor-beta1" 6 : 22141-, 2016

25 Latorre E, "Downregulation of HuR as a new mechanism of doxorubicin resistance in breast cancer cells" 11 : 13-, 2012

26 Mrena J, "Cyclooxygenase-2 is an independent prognostic factor in gastric cancer and its expression is regulated by the messenger RNA stability factor HuR" 11 : 7362-7368, 2005

27 Kotta-Loizou I, "Current evidence and future perspectives on HuR and breast cancer development, prognosis, and treatment" 18 : 674-688, 2016

28 Vidal-Vanaclocha F, "Clinical and experimental approaches to the pathophysiology of interleukin-18 in cancer progression" 25 : 417-434, 2006

29 Cha JD, "Association between expression of embryonic lethal abnormal vision-like protein HuR and cyclooxygenase-2 in oral squamous cell carcinoma" 33 : 627-637, 2011