To investigate gene(s) being regulated by ∆9-tetrahydrocannabinol (∆9-THC), we performed DNA microarray analysis of human breast cancer MDA-MB-231 cells, which are poorly differentiated breast cancer cells, treated with ∆9-THC for 48 hr at an IC50 concentration of approximately 25 µM. Among the highly up-regulated genes (> 10-fold) observed, fatty acid 2-hydroxylase (FA2H) was significantly induced (17.8-fold). Although the physiological role of FA2H has not yet been fully understood, FA2H has been shown to modulate cell differentiation. The results of Oil Red O staining after ∆9-THC exposure showed the distribution of lipid droplets (a sign of the differentiated phenotype) in cells. Taken together, the results obtained here indicate that FA2H is a novel ∆9-THC-regulated gene, and that ∆9-THC induces differentiation signal(s) in poorly differentiated MDA-MB-231 cells.
2013 The Japanese Society of Toxicology