Anti-sense morpholino oligonucleotide assay shows critical involvement for NF-kappaB activation in the production of Wnt-1 protein by HepG2 cells: oncology implications.

The link of proto-oncogenic protein Wnt-1 production with NF-kappaB activation has been functionally demonstrated in PC12 cells, a rat pheochromocytoma cell line of neural crest lineage, while it is not yet verified in human cells. The link can be indirectly supported in our previous report that functional proteomics identifies enhanced expression of NF-kappaB-associated Wnt-1 production in human hepatocellular carcinoma tissues. This study aimed to further validate this link in human cells using anti-sense strategy. The effects of sequence-specific anti-sense morpholino oligonucleotides (ONs) targeting against pre-mRNA sequences of human p50 and p65 subunits of NF-kappaB as well as Wnt-1 genes were investigated. It revealed that all the three morpholino ONs inhibited NF-kappaB activation in human hepatoblastoma cell line HepG2 cells along with decreased Wnt-1 production. Chromatin immunoprecipitation assay ascertained the direct binding of NF-kappaB-p50 to the Wnt-1 promoter. Additionally, anti-P50 and anti-P65 morpholino ONs also repressed the phosphorylation of Ikappa Balpha which temporarily correlated with the inhibition of NF-kappaB activation accompanied by decreased Wnt-1 production by HepG2 cells. In summary, NF-kappaB activation is critically involved in the production of Wnt-1 by HepG2 cells. These results may have important oncology implications in treating patients with NF-kappaB-associated Wnt-1-producing cancers.