Identification of genes regulated by Wnt/beta-catenin pathway and involved in apoptosis via microarray analysis.

Background: Wnt/beta-catenin pathway has critical roles in development and oncogenesis. Although significant progress has been made in understanding the downstream signaling cascade of this pathway, little is known regarding Wnt/beta-catenin pathway modification of the cellular apoptosis.

Methods: To identify potential genes regulated by Wnt/beta-catenin pathway and involved in apoptosis, we used a stably integrated, inducible RNA interference (RNAi) vector to specific inhibit the expression and the transcriptional activity of beta-catenin in HeLa cells. Meanwhile, we designed an oligonucleotide microarray covering 1384 apoptosis-related genes. Using oligonucleotide microarrays, a series of differential expression of genes was identified and further confirmed by RT-PCR.

Results: Stably integrated inducible RNAi vector could effectively suppress beta-catenin expression and the transcriptional activity of beta-catenin/TCF. Meanwhile, depletion of beta-catenin in this manner made the cells more sensitive to apoptosis. 130 genes involved in some important cell-apoptotic pathways, such as PTEN-PI3K-AKT pathway, NF-kappaB pathway and p53 pathway, showed significant alteration in their expression level after the knockdown of beta-catenin.

Conclusion: Coupling RNAi knockdown with microarray and RT-PCR analyses proves to be a versatile strategy for identifying genes regulated by Wnt/beta-catenin pathway and for a better understanding the role of this pathway in apoptosis. Some of the identified beta-catenin/TCF directed or indirected target genes may represent excellent targets to limit tumor growth.