Targeted disruption of the galectin-3 gene results in decreased susceptibility to NNK-induced lung tumorigenesis: An oligonucleotide microarray study

Purpose: Galectin-3, a β-galactoside-binding animal lectin is a multifunctional protein, which regulates cell growth, cell adhesion, cell proliferation, angiogenesis, and apoptosis, and in turn contributes to tumorigenesis and metastasis. The aim of this study was to clarify the role or related mechanisms of galectin-3 in lung carcinogenesis. Methods: We administrated 4-(methylnitrosamino)-1-(3-pyridyle)-1-butanone (NNK), a powerful chemical carcinogen into galectin-3 wild-type (gal3+/+) and galectin-3 knock-out (gal3-/-) CD1 mice by intraperitoneal injection, examined the expression status of 22,690 mouse genes of the NNK-induced tumors using Affymetrix GeneChip mouse expression 430 A arrays, and then analyzed functional network and gene ontology by Ingenuity Pathway Analysis. Real-time PCR was also employed to partially confirm the genechip data. Results: Compared with the gal3+/+ mice, the incidence of lung tumors was significantly low in gal3-/- mice after 32 weeks (28.6 vs 52.1%, P < 0.05). Pathway analysis indicated that galectin-3 up-regulated carcinogenesis-related genes (e.g. B-cell receptor, ERK/MAPK, and PPAR signalings) in normal condition, and lung cancer and NNK-induced gene expression associated with cellular growth (e.g. Wnt/β-catenin signaling) or immunological disease (e.g. EGF and PDGF signalings) in lung carcinogenesis with or without the galectin-3 control, respectively. Conclusion: Disrupted galectin-3 may attenuate the lung carcinogenesis due to its regulatory role in the B-cell receptor, ERK/MAPK, and PPAR signal pathways.