The Function and Mechanism of microRNA-155 in Breast Cancer

A research article of Liu Mo-Fang´s group and Wang En-Duo´s group in Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences was recently published on Cancer Research (70(8) April 15, 2010). The work studied the function and mechanism of microRNA-155 (miR-155) in breast cancer.

 

miR-155 is normally restricted to hematopoietic cells and required for lymphocyte development. The microRNA is also observed to be overexpressed in hematopoietic malignancies and various solid tumors, including breast, lung, colon, pancreatic, and thyroid cancers. However, the role of miR-155 in cancers, especially in breast tumorigenesis, has not yet been defined.

 

Shuai Jiang and his colleagues found miR-155 significantly promotes the proliferation and anchorage-independent growth of breast cancer cells in vitro, and stimulates the tumor growth of breast cancer cells in Xenograft assays in nude mice, indicating that miR-155 acts as an oncomiR in breast cancer cells. They further demonstrated that downregulation of tumor suppressor gene socs1 and consequently contributing to constitutive STAT3 activation in breast cancer by miR-155 is an authentic mechanism of miR-155-mediated oncogenesis in breast tumors. Importantly, the cross-talk between miR-155, socs1, and STAT3 signaling may provide a new mechanism for inflammation-associated tumorigenesis and suggests the potential use of miR-155 and SOCS1 in cancer therapy.

 

This work was supported by grants from the Ministry of Science and Technology of China, the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the Science and Technology Commission of Shanghai Municipality.