Estrogen receptor beta reduces colon cancer metastasis through a novel miR-205-PROX1 mechanism

• Colon cancer is a common cause of cancer death in the Western world. Accumulating evidence supports a protective role of estrogen via estrogen receptor beta (ER beta) but the mechanism of action is not known. Here, we elucidate a molecular mechanism whereby ER beta represses the oncogenic prospero homebox 1 (PROX1) through the upregulation of miR-205. We show that PROX1 is a potential target of miR-205 and that in clinical specimens from The Cancer Genome Atlas data, ER beta and miR-205 are decreased in colorectal cancer tissue compared to non-tumorous colon, while PROX1 levels are increased. Through mechanistic studies in multiple colorectal cancer cell lines, we show that ER beta upregulates miR-205, and that miR-205 targets and represses PROX1 through direct interaction with its 3' UTR. Through the generation of intestine-specific ER beta knockout mice, we establish that this pathway is correspondingly regulated in normal intestinal epithelial cells in vivo. Functionally, we demonstrate that miR-205 decreases cell proliferation and decreases migratory and invasive potential of colon cancer cells, leading to a reduction of micrometastasis in vivo. In conclusion, ER beta in both normal and cancerous colon epithelial cells upregulates miRNA-205, which subsequently reduces PROX1 through direct interaction with its 3' UTR. This results in reduced proliferative and metastatic potential of the cells. Our study proposes a novel pathway that may be exploited using ER beta-selective agonists and/or miR-205-replacement therapy in order to improve preventive and therapeutic approaches against colon cancer.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

Nyckelord

colorectal cancer

PROX1

estrogen receptor

microRNA

metastasis

Publikations- och innehållstyp

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