ALDH isozymes downregulation affects cell growth, cell motility and gene expression in lung cancer cells.
BACKGROUND
Aldehyde dehydrogenase isozymes ALDH1A1 and ALDH3A1 are highly expressed in non small cell lung cancer. Neither the mechanisms nor the biologic significance for such over expression have been studied.


METHODS
We have employed oligonucleotide microarrays to analyze changes in gene profiles in A549 lung cancer cell line in which ALDH activity was reduced by up to 95% using lentiviral mediated expression of siRNA against both isozymes (Lenti 1+3). Stringent analysis methods were used to identify gene expression patterns that are specific to the knock down of ALDH activity and significantly different in comparison to wild type A549 cells (WT) or cells similarly transduced with green fluorescent protein (GFP) siRNA.


RESULTS
We confirmed significant and specific down regulation of ALDH1A1 and ALDH3A1 in Lenti 1+3 cells and in comparison to 12 other ALDH genes detected. The results of the microarray analysis were validated by real time RT-PCR on RNA obtained from Lenti 1+3 or WT cells treated with ALDH activity inhibitors. Detailed functional analysis was performed on 101 genes that were significantly different (P < 0.001) and their expression changed by > or = 2 folds in the Lenti 1+3 group versus the control groups. There were 75 down regulated and 26 up regulated genes. Protein binding, organ development, signal transduction, transcription, lipid metabolism, and cell migration and adhesion were among the most affected pathways.


CONCLUSIONS
These molecular effects of the ALDH knock-down are associated with in vitro functional changes in the proliferation and motility of these cells and demonstrate the significance of ALDH enzymes in cell homeostasis with a potentially significant impact on the treatment of lung cancer.
Moreb
Jan S
JS
Department of Medicine, University of Florida, Gainesville, Florida, USA. morebjs@medicine.ufl.edu
Baker
Henry V
HV
Chang
Lung-Ji
LJ
Amaya
Maria
M
Lopez
M Cecilia
MC
Ostmark
Blanca
B
Chou
Wayne
W
D000444:Aldehyde Dehydrogenase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000080924:Aldehyde Dehydrogenase 1 Family; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002877:Chromosomes, Human / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008175:Lung Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D034741:RNA, Small Interfering; D050697:Retinal Dehydrogenase
D004791:Enzyme Inhibitors; D007527:Isoenzymes; D034741:RNA, Small Interfering; D000080924:Aldehyde Dehydrogenase 1 Family; C480021:ALDH3A1 protein, human; D000444:Aldehyde Dehydrogenase; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase