Colorectal cancer (CRC) is one of the leading causes of cancer-related mortality worldwide (1). The majority of CRC patients are in advanced stages of the disease before any symptoms appear, so the survival rate after diagnosis is very low. It’s clear that earlier detection of CRC and improved diagnostic and therapeutic approaches will be key in improving survival rates. To achieve this goal, researchers must first gain a better understanding of the mechanisms that lead to CRC and identify new biomarkers.
Long non-coding RNAs (lncRNAs) are a class of newly identified non-coding RNA molecules that are regarded as key regulators in many biological processes. Recent studies show that lncRNAs are often dysregulated in various cancers, including CRC (view list), making a strong case for using lncRNAs as potential cancer markers (read the blog post). Also, dysregulation of lncRNA in cancer cells often induces apoptosis, or cell death, suggesting that lncRNAs can be useful as therapeutic targets.
lncRNA Loc554202, a 2166-bp transcript on human chromosome 9p21.3, is the host gene of miR-31 and dysregulated in breast (2) and lung (3) cancer cells. Loc554202’s role in CRC was unclear until a recent study by Ding and colleagues (4).
The research group analyzed Loc554202 expression in human CRC tissues and cell lines using quantitative real-time polymerase chain reaction (qRT-PCR). Ding and colleagues found that Loc554202 expression was decreased in CRC tissue samples and cell lines compared to normal samples. Its downregulation was associated with an advanced pathological stage and a large tumor size. Functional studies of Loc554202 indicated that its increased expression could decrease cell proliferation and induce apoptosis in vitro and in vivo. Cell apoptosis was partially regulated through activation of specific caspase cleavage cascades.
The researchers’ findings are the first to suggest that lncRNA Loc554202 acts as a tumor-inhibiting factor in CRC. While follow-up investigations are necessary to strengthen these findings, this study sheds light on a lncRNA as a potential prognostic biomarker or a target for new cancer therapies.
Want to know more about lncRNAs in CRC? Check out the table below, and view the top 84 lncRNAs differentially expressed in tumors vs normal tissue here!
|lncRNA||Role in CRC|
|H19||Targets RB to promote human CRC cell growth / suppresses polyp count in mouse CRC|
|MEG3||Inhibits tumor cell proliferation by inducing p53 accumulation|
|CCAT1||Possibly an early biomarker – overexpressed in metastases and peripheral blood|
|CRNDE||Another possible early biomarker, overexpressed in CRC tissues|
|OCC-1||Overexpressed in CRC samples|
|PCAT-1||Biomarker of poor prognosis when overexpressed in CRC tissues|
|PVT-1||Anti-apoptotic function in CRC|
|SNHG16 (ncRAN)||Increases migration and invasion of CRC cells in vitro|
Information in the table compiled from References 5-8.
1. Siegel, R., Desantis, C. and Jemal, A. (2014) Colorectal cancer statistics. CA Cancer J. Clin. 64,104.
2. Shi, Y. et al. (2014) Long non-coding RNA Loc554202 regulates proliferation and migration in breast cancer cells. Biochem. Biophys. Res. Commun. 446, 448.
3. Xi, S. et al. (2010) Cigarette smoke induces C/EBP-beta-mediated activation of miR-31 in normal human respiratory epithelia and lung cancer cells. PLOS One. 5, e13764.
4. Ding, J. et al. (2015) Long non-coding RNA Loc554202 induces apoptosis in colorectal cancer cells via the caspase cleavage cascades. J. Exp. Clin. Cancer Res. 11, 100.
5. Gene list, Human Cancer PathwayFinder RT² lncRNA PCR Array.
6. Ye, L-C. et al. (2015) Involvement of long non-coding RNA in colorectal cancer: from benchtop to bedside. Oncol. Lett. 9, 1039. (Review)
7. Takahashi, Y. et al. (2014) Amplification of PVT-1 is involved in poor prognosis via apoptosis inhibition in colorectal cancers. Br. J. Cancer 110, 164.