Preventive effect of methanol extract from Agrocybe cylindracea (MEAC) mushroom on the cooking oil fumes-induced expressions of cyclooxygenase-2 via suppression of nuclear factor-kappaB (NF-kB) in CL-3 cells

Methanol extract from Agrocybe cylindracea strain B (MEAC) mushroom is reported to suppress reactive oxygen species (ROS) production and DNA oxidative damage induced by cooking oil fumes (COF). This study examined the effects of MEAC on COF-stimulated expression of the cyclooxygenase-2 (COX-2) and cytochrome P450 CYP1A1 genes in human lung adenocarcinoma CL-3 cells. MEAC did not alter COF-stimulated CYP1A1 mRNA expression. However, MEAC significantly inhibited COF (100 μg/mL) stimulation of COX-2 mRNA and protein levels in a dose-dependent manner. The concentration of MEAC that decreased COF-stimulated COX-2 protein expression by 50% was 500 μg/mL. These data suggest that MEAC selectively affects particular types of the COF-mediated genes. COX-2 is reported to be regulated by the nuclear factor-kappaB (NF-kB) pathway. The gel retardation assay was used and showed that MEAC alone did not alter the basal NF-kB DNA binding activity; in the presence of COF, it dose-dependently suppressed COF-increased activity of NF-kB. These data suggest that MEAC may exert its anti-COF action on COX-2 gene expression via the NF-kB pathway. The results of this study support that MEAC mediates the COF-stimulated ROS production and DNA damage in CL-3 lung cancer cells.