Abstract 3165: Docosahexaenoic acid attenuates survival and progression in subtype-specific breast cancer by modifying Myc activity

Overexpression of Myc in breast cancer is associated with poor prognosis and has a unique profile distribution among subtypes. Myc overexpression has been shown to be greatest in basal-like tumors, ∼50%, and least in luminal Her2-overexpressing tumors, ∼9%. Previous studies from our laboratory have identified a relationship between docosahexaenoic acid (DHA, C22:6 n-3) treatment and Myc activity and the effect seems to be specific to the breast cancer subtype and Myc overexpression profile, but is still unclear. In the current study, we investigated the effect of DHA on tumor growth, survival, and invasion in a high Myc expressing cell line, basal-like MDA-MB-231, and a low Myc expressing cell line, luminal Her2-overexpressing BT-474, in vitro. Basal expression analysis confirmed Myc overexpression levels in each cell line. While DHA treatment in the basal-like MDA-MB-231 cells significantly decreased Myc transcriptional activity and p-T58/S62-c-Myc phosphorylation status, the opposite response was observed with DHA treatment in the BT-474 luminal Her2-overexpressing cells, significantly enhancing Myc transcriptional activity and phosphorylation status. Although different responses in Myc activity existed between the two subtype-specific breast cancers, cell viability and apoptosis assays produced similar findings, revealing decreased cellular viability and increased early and late-apoptotic cellular status in response to DHA treatment. Additionally, dramatic decreases in...
Source: Cancer Research - Category: Cancer & Oncology Authors: Tags: Tumor Biology Source Type: research