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Functional characterization of 15-lipoxygenase-1 expression in human colorectal carcinoma cell line ht-29

Tunçay, Seda
Colorectal carcinoma (CRC) is often lethal when invasion and/or metastasis occur. 15-lipoxygenase-1 (15-LO-1), an enzyme of the inflammatory eicosanoid pathway, oxidatively metabolizes linoleic acid and its expression is repressed in CRC. In the present study, the hypothesis that the lack of 15-LO-1 expression in CRC cells may contribute to the tumorigenesis was investigated. Therefore 15-LO-1 was introduced to colon cancer cell line HT-29 that does not have detectable levels of the 15-LO-1. The HT-29 cells were transiently transfected with the eukaryotic expression vector pcDNA3.1-15-LO-1 and the effects of 15-LO-1 expression on the proliferation, apoptosis as wells as metastatic potential of the cells were investigated. Cellular proliferation was analyzed by MTT assay and the apoptotic potential of 15-LO-1 was evaluated by acridine orange, floating cell ratio and caspase-3 assays as well as expression levels of the antiapoptotic protein XIAP. Cellular migration and invasion were investigated by Boyden chamber migration and Matrigel invasion assay.The data indicates that 15-LO-1 expression significantly decreased cell proliferation and increased apoptosis. In addition, a significant reduction was observed in migratory and invasive capacity 15-LO-1 expression also significantly reduced the expression of metastasis associated 1 protein (MTA-1). Taken together we propose that 15-LO-1 expression in CRC can inhibit colon cancer cell growth through induction of apoptotic cell death and may contribute to the inhibition of metastatic capacity in vitro which may be exploited for therapeutic purposes.