title: Arachidonic acid suppresses growth of human lung tumor A549 cells through down-regulation of ALDH3A1 expression.
abstract: Expression of aldehyde dehydrogenase 3A1 (ALDH3A1) in certain normal and tumor cells is associated with protection against the growth inhibitory effect of reactive aldehydes generated during membrane lipid peroxidation. We found that human lung tumor (A549) cells, which express high levels of ALDH3A1 protein, were significantly less susceptible to the antiproliferative effects of 4-hydroxynonenal compared to human hepatoma HepG2 or SK-HEP-1 cells that lack ALDH3A1 expression. However, A549 cells became susceptible to lipid peroxidation products when they were treated with arachidonic acid. The growth suppression of A549 cells induced by arachidonic acid was associated with increased levels of lipid peroxidation and with reduced ALDH3A1 enzymatic activity, protein, and mRNA levels. Furthermore, arachidonic acid treatment of the A549 cells resulted in an increased expression of peroxisome proliferator-activated receptor gamma (PPARgamma), whereas NF-kappaB binding activity was inhibited. Blocking PPARgamma using a selective antagonist, GW9662, prevented the arachidonic acid-mediated reduction of ALDH3A1 expression as well as the growth inhibition of A549 cells, suggesting the central role of PPARgamma in these phenomena. The increase in PPARgamma and the reduction in ALDH3A1 were also prevented by exposing cells to vitamin E concomitant with arachidonic acid treatment. In conclusion, our data show that the arachidonic acid-induced suppression of A549 cell growth is associated with increased lipid peroxidation and decreased ALDH3A1 expression, which may be due to activation of PPARgamma.
authors.affiliation: Department of Experimental Medicine and Oncology, University of Turin, Corso Raffaello 30, 10125 Turin, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Muzio
authors.forename: Antonella
authors.initials: A
authors.lastname: Trombetta
authors.forename: Marina
authors.initials: M
authors.lastname: Maggiora
authors.forename: Germana
authors.initials: G
authors.lastname: Martinasso
authors.forename: Vasilis
authors.initials: V
authors.lastname: Vasiliou
authors.forename: Natalie
authors.initials: N
authors.lastname: Lassen
authors.forename: Rosa A
authors.initials: RA
authors.lastname: Canuto
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics*; D016718:Arachidonic Acid / Q000494:pharmacology*; D001483:Base Sequence; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D017931:DNA Primers; D015536:Down-Regulation / Q000187:drug effects*; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D008175:Lung Neoplasms / Q000201:enzymology / Q000473:pathology*; D047495:PPAR gamma / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D047495:PPAR gamma; D012333:RNA, Messenger; D016718:Arachidonic Acid; C480021:ALDH3A1 protein, human; D000444:Aldehyde Dehydrogenase