Abstract
BackgroundAberrant expression of long noncoding RNAs (lncRNAs) has frequently been reported in cancer studies, including those of colorectal cancer (CRC). Increasing evidence suggests that lncRNAs are significantly correlated with the pathogenesis, development and metastasis of cancer. Loc554202 is a 2166-bp transcript on human chromosome 9p21.3, the expression of which is dysregulated in breast and lung cancer cells. However, its role in CRC remains under investigation.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR) was carried out to assess the relative expression of Loc554202 in CRC cell lines and tissues. Gain and/or loss of function approaches were used to investigate the potential functional roles in cell proliferation and apoptosis in vitro and in vivo. qRT-PCR, western-blotting and immunohistochemistry were used to evaluate the mRNA and protein expression of apoptosis-related factors.ResultsLoc554202 was significantly downregulated in cancerous tissues and CRC cell lines compared with adjacent normal tissue and a normal human intestinal epithelial cell line. Low Loc554202 expression was closely associated with advanced pathologic stage and a larger tumor size. The overexpression of Loc554202 decreased the cell proliferation and induced apoptosis in vitro and hindered tumorigenesis in vivo. Loc554202 regulated cell apoptosis partly through the activation of specific caspase cleavage cascades.ConclusionOur results suggest that Loc554202 may play an important role in the progression of CRC and could be a candidate prognostic biomarker or a target for new cancer therapies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-015-0217-7) contains supplementary material, which is available to authorized users.
Highlights
Colorectal cancer (CRC), as the third most common cancer affecting the gastrointestinal tract, is a common type of cancer worldwide, and is associated with a high mortality rate due to its rapid progression and advanced tumor presentation at the time of diagnosis [1,2,3]
To further understand the significance of Loc554202 expression in colorectal cancer (CRC), we evaluated the correlation of Loc554202 expression with various clinicopathological features (Table 1)
We examined the expression of Loc554202 in five human colorectal cancer cell lines (HT-29, SW480, RKO, HCT116, and DLD1) and a normal colonic epithelial cell (HCoEpiC)
Summary
Colorectal cancer (CRC), as the third most common cancer affecting the gastrointestinal tract, is a common type of cancer worldwide, and is associated with a high mortality rate due to its rapid progression and advanced tumor presentation at the time of diagnosis [1,2,3]. Increasing evidence has shown that lncRNAs have important biological functions are closely related to human diseases, especially cancer [7,8,9,10]. They may function as oncogenes [11, 12] or anti-oncogenes [13, 14] similar to protein-coding genes, and their dysregulated expression is significantly correlated with carcinogenesis [15]; Ding et al Journal of Experimental & Clinical Cancer Research (2015) 34:100 they may be considered to be promising candidate biomarkers for diagnosing cancer and may represent therapeutic target in the future.
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