| Popis: |
Growth hormone Receptor (GHR) is a class I cytokine receptor. Under normal conditions, it is expressed in most tissues of the body.In addition to its presence in healthy tissue, GHR has been detected in cancer cells and tumors. There has been accumulating evidence that implicates GHR activation in carcinogenesis. Most research to date has focused on breast and prostate cancer, with a few studies in other cancer types. A limited number of studies have investigated a direct effect of GH on cancer cells, and even fewer have examined the mechanism of GH action in cancer cells. Our investigations began with a survey of gene expression in the 60 cell lines of the National Cancer Institute’s NCI60 panel. All of the metastatic melanoma lines examined show high expression of GHR. Five of the melanoma cell lines were treated with GH. In three of the cell lines, GH treatment increases cell growth. In one cell line, GH has a biphasic effect based on dose; a low dose moderately inhibits cell growth, while a high dose induces growth. Cell signaling pathways were analyzed as well. Some activation of mTOR was detected, along with strong STAT5 phosphorylation with GH treatment. These findings may have relevance to growth and invasion of metastatic melanoma cells in vivo. Further studies are warranted to determine if therapeutic interventions aimed at GH signaling might be beneficial in treatment of metastatic melanoma. |
