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miR-7 suppresses stomach cancer

Date:
August 10, 2015
Source:
The Rockefeller University Press
Summary:
The microRNA miR-7 suppresses stomach cancer by inhibiting a key signaling pathway, and that this protective mechanism is compromised by the cancer-causing bacterium H. pylori, researchers announce. Finding drugs capable of inducing miR-7 could therefore prove to be an effective treatment against the progression of gastric cancer.
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Zhao et al. identify a regulatory circuit in human gastric cells that becomes compromised by H. pylori-induced inflammation and leads to the development of stomach cancer.
Credit: Zhao et al., 2015

A study in The Journal of Cell Biology reveals that the microRNA miR-7 suppresses gastric (stomach) cancer by inhibiting a key signaling pathway, and that this protective mechanism is compromised by the cancer-causing bacterium H. pylori. Finding drugs capable of inducing miR-7 could therefore prove to be an effective treatment against the progression of gastric cancer.

Gastric cancer is the fourth most common cancer and the third leading cause of cancer-related deaths worldwide, according to the National Institutes of Health. miR-7, which is frequently decreased in gastric cancers, can stop the cancer cells from spreading to other tissues by inhibiting a particular growth factor receptor (called IGF1R). Whether miR-7 also suppresses earlier stages of gastric cancer is unknown, however, so researchers in China screened for new targets of the microRNA.

Dai-Ming Fan and colleagues found that miR-7 directly targets the genes RELA and FOS, which encode proteins involved in the pro-oncogenic NF-κB and AP-1 signaling pathways, respectively. In human gastric cancer samples, low miR-7 levels correlated with elevated levels of RELA and FOS proteins and poor patient survival. Increasing levels of miR-7 reduced RELA and FOS levels and inhibited tumor growth in mice.

The researchers found that, as well as directly suppressing RELA expression, miR-7 could control the protein's activation by targeting its upstream kinase (IKKε) in the NF-κB pathway. Yet, this same pathway was itself able to repress miR-7 expression, indicating that miR-7 would be unable to restrain RELA's activity if the NF-κB pathway were strongly activated.

Chronic H. pylori infection is a major risk factor for gastric cancer, in part because the bacterium can hyperactivate the NF-κB pathway. Accordingly, Fan and colleagues found that culturing H. pylori with gastric cells activated IKKε and RELA, and reduced the expression of miR-7, a potentially key step in the transformation of healthy gastric cells into malignant ones.


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Materials provided by The Rockefeller University Press. Note: Content may be edited for style and length.


Journal Reference:

  1. X.-D. Zhao, Y.-Y. Lu, H. Guo, H.-H. Xie, L.-J. He, G.-F. Shen, J.-F. Zhou, T. Li, S.-J. Hu, L. Zhou, Y.-N. Han, S.-L. Liang, X. Wang, K.-C. Wu, Y.-Q. Shi, Y.-Z. Nie, D.-M. Fan. MicroRNA-7/NF- B signaling regulatory feedback circuit regulates gastric carcinogenesis. The Journal of Cell Biology, 2015; DOI: 10.1083/jcb.201501073

Cite This Page:

The Rockefeller University Press. "miR-7 suppresses stomach cancer." ScienceDaily. ScienceDaily, 10 August 2015. <www.sciencedaily.com/releases/2015/08/150810091857.htm>.
The Rockefeller University Press. (2015, August 10). miR-7 suppresses stomach cancer. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2015/08/150810091857.htm
The Rockefeller University Press. "miR-7 suppresses stomach cancer." ScienceDaily. www.sciencedaily.com/releases/2015/08/150810091857.htm (accessed May 23, 2017).

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