Down‐regulation of long non‐coding RNA HOTAIR inhibits invasion and migration of oesophageal cancer cells via up‐regulation of microRNA‐204
Authors: Yuan Zhuang
Lu-Ning Li
Peng Tan
Xiu-Tian Zhang
Zong-Bu Yu
Ai-Hua Wang
Journal: Journal of Cellular and Molecular Medicine (2019)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: HOX transcript antisense RNA; MicroRNA-204; homeobox C8; invasion; long non-coding RNA
Affiliations: Department of Gastroenterology, Linyi People's Hospital, Linyi, P.R. China., Internal Medicine Teaching and Research Section, Shandong Medical College, Linyi, P.R. China., Histology and Embryology Teaching and Research Section, Shandong Medical College, Linyi, P.R. China.

Abstract:  Oesophageal cancer is a progressive tumour with high mortality. However, therapies aimed at treating oesophageal cancer remain relatively limited. Accumulating studies have highlighted long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR), microRNA-204 (miR-204) and homeobox C8 (HOXC8) in the progression of oesophageal cancer. Herein, we tried to demonstrate the function of HOTAIR, miR-204 and HOXC8 in oesophageal cancer and their relationship. Differentially expressed genes involved in oesophageal cancer were identified. The endogenous expression of HOTAIR and miR-204 in oesophageal cancer cell lines was altered to elucidate their effects and to identify the interaction among HOTAIR, miR-204 and HOXC8. We also explored the underlying regulatory mechanisms of HOTAIR and miR-204 with siRNA against HOTAIR, miR-204 mimic or miR-204 inhibitor. Cell proliferation, migration, invasion and apoptosis were subsequently detected. Xenograft in nude mice was induced to evaluate tumourigenicity. miR-204 was down-regulated, while HOTAIR and HOXC8 were up-regulated in the oesophageal cancer tissues. HOTAIR could competitively bind to miR-204 and miR-204 could further target HOXC8. The oesophageal cancer cells treated with si-HOTAIR or miR-204 mimic exhibited decreased expression levels of HOXC8, Vimentin and MMP-9, but increased E-cadherin level. Silenced HOTAIR or elevated miR-204 inhibited proliferation, migration and invasion, along with stimulated apoptosis of oesophageal cancer cells. In summary, our results show that lncRNA HOTAIR could specifically bind to miR-204 as a competing endogenous RNA and regulate miR-204 and HOXC8. Hence, down-regulation of HOTAIR could inhibit progression of oesophageal cancer, indicating a novel target for oesophageal cancer treatment. 

Retracted: No

PubPeer comments:
 Please can the authors clarify if the samples used in the Biomolecules paper (2019) were the same as those used in the Life Sciences paper (2020) indicated below? If they were different, then what was the difference? Both papers analyzed TIPE expression in lung cancer tissues and the Tissue microarray section detailing the tissues analyzed is identical, including the specific number of tissues for each subtype. This relates to Figure 1 in both papers. The data trends look similar in both papers but not identical, suggesting that this is not a duplication. Probably, there were technical differences in the 2 papers. A clarification from the authors will be appreciated. **Paper 1: Inflection of Akt mTOR STAT-3 cascade in TNF-u03b1 induced protein 8 mediated human lung carcinogenesis. Life Sciences (2020). PMID: 32976884.** 2.1. Tissue microarray Immunohistochemical analysis was done to analyze the expression of TIPE in different stages, grades and pathological conditions of lung cancer tissues compared to normal lung tissues. For this analysis, tissue microarray (TMA) which contained paraffin-embedded tissues (US Biomax, Inc., Cat. No. LC1503) from different individuals were used. The slide comprised of a total of 75 tissues (duplicated cores from the same patient in all cases) which include **29 adenocarcinoma, 3 adenosquamous carcinoma, 29 squamous cell carcinoma, 2 bronchioalveolar carcinoma, 4 small cell undifferentiated carcinoma, 2 large cell carcinoma, 1 neuroendocrine carcinoma and 5 normal lung tissues** (Suppl. Table 1). **Paper 2: TIPE2 Induced the Proliferation, Survival, and Migration of Lung Cancer Cells Through Modulation of Akt mTOR NF-u0014B Signaling Cascade. Biomolecules (2019).** 2.1. Tissue Microarray Expression of TIPE2 in normal lung tissues and diu000berent stages of lung cancer tissues was determined with the help of immunohistochemical analysis using tissue microarray (TMA) containing parau000en-embedded normal and malignant lung tissues (US Biomax, Inc., Cat. No. LC1503, Derwood, MD, USA). The TMA slide contained a total of 75 tissues, 150 cores (duplicated cores from the same patient in all cases) from diu000berent individuals: **29 adenocarcinoma, 3 adenosquamous carcinoma, 29 squamous cell carcinoma, 2 bronchioalveolar carcinoma, 4 small cell undiu000berentiated carcinoma, 2 large cell carcinoma, 1 neuroendocrine carcinoma, and 5 normal lung tissues **(Table S1). ![file] ,