LncRNA HOTAIR promotes colon cancer development by down-regulating miRNA-34a

C.-L. Peng, X.-J. Zhao, C.-C. Wei, J.-W. Wu

Department of Gastrointestinal Surgery, Suzhou First People’s Hospital, Suzhou, China. wjw@gmc.edu.cn

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• Oncology

OBJECTIVE: To investigate the characteristics of long non-coding RNA (lncRNA) HOTAIR in colon cancer, and to further explore its function in the development of colon cancer and its potential regulatory mechanisms.

PATIENTS AND METHODS: Quantitative Real-time polymerase chain reaction (qRT-PCR) was performed to detect HOTAIR expression in 72 colon cancer tissues along with adjacent normal tissues. Meanwhile, the relationship between HOTAIR level and colon cancer pathological parameters and patient prognosis were analyzed, respectively. QRT-PCR further verified the HOTAIR expression in colon cancer cells. Besides, knockdown and overexpression of HOTAIR models were constructed using lentivirus in HT29 and HCT-116 colon cancer cell lines. Cell counting kit-8 (CCK-8), 5-ethynyl-2’-deoxyuridine (EDU) and cell colony formation assays were used to analyze the effects of HOTAIR on biological function of colon cancer cell. In addition, dual luciferase reporter gene assay was performed to explore the underlying mechanisms.

RESULTS: QRT-PCR results showed that HOTAIR expression in colon cancer was significantly higher than that in normal tissues. The incidence of distant metastasis was higher in patients with high expression of HOTAIR while their survival rate was lower than that of patients with low HOTAIR expression. Meanwhile, cell proliferation, invasion as well as migration ability of the cells in HOTAIR knockdown group was significantly decreased than those in the negative control group. QRT-PCR results showed that mRNA levels of miR-34a and HOTAIR in colon cancer tissues were negatively correlated. Besides, luciferase reporter gene assay revealed that overexpression of miR-34a significantly attenuated the luciferase activity of the wild-type HOTAIR vector group without attenuating the mutant HOTAIR vector group (p>0.05) In addition, the recovery experiment also found a mutual regulation between HOTAIR and miR-34a, together they could affect the malignant progression of colon cancer.

CONCLUSIONS: HOTAIR expression was significantly increased in colon cancer, which was in association with distant metastasis and poor prognosis of colon cancer. In addition, HOTAIR may promote malignant progression of colon cancer by regulating miR-34a.

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