Long noncoding RNAs (lncRNA)  have been demonstrated to extensively participate in a wide spectrum of biological activities ranging from embryogenesis and cancer progression. HOX transcript antisense RNA (Hotair), an lncRNA located in the HOXC locus, has been reported to play an important role in carcinogenesis. As a well‐known oncogene, it potentiates cancer metastasis and tumor progression. And it also serves as a biomarker for poor prognosis and tumor recurrence. In this study, Hotair was found to be upregulated in colorectal cancer (CRC) cells and clinical specimens. Further investigation showed that knockdown of Hotair dramatically suppressed cell proliferation and colony formation, suggesting that Hotair may stimulate tumorigenesis of CRC. The enhancer of zeste homolog 2 (EZH2), a regulator of epigenetic modification, was upregulated in CRC cells and clinical samples. And the silence of EZH2 significantly suppressed cell viability and colony formation. Furthermore, the RNA immunoprecipitation assay revealed that Hotair directly bound EZH2 in CRC cells. In conclusion, Hotair mediated tumorigenesis via recruiting EZH2, which might shed light on the development of a novel therapeutic approach for patients with CRC.

Rectal cancer (RC) is a common malignant tumor with high mortality. MR imaging plays an important role in treatment decision making of RC. Unfortunately, the contents (gas and feces) in the rectum often induce artifacts and thus negatively affect the depicting and staging of RC. We developed a new protocol for MR rectography using oral administration of iso-osmotic mannitol to distend lumen after bowel cleansing preparation. Fused MR rectography and high resolution diffusion weighted imaging (DWI) is then performed to facilitate detection and staging of RC. Our present technique can eliminate the effect of gas and feces on image quality, especially on DWI, and can achieve satisfactory bowel distention, lesion depicture and visualization of surgical planes. Fused high resolution DWI and MR rectography can be a promising technique to improve the accuracy of RC local staging.

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