WNT2B: comparative integromics and clinical applications (Review).

We cloned and characterized human WNT2B (WNT13) in 1996. Following our discovery of human WNT2B, others and we characterized mouse, rat, chicken and zebrafish WNT2B orthologs. Here, comparative integromics analyses on WNT2B and its clinical applications are reviewed. WNT2B-ST7L-CAPZA1 locus at human chromosome 1p13.2 and WNT2-ST7-CAPZA2 locus at human chromosome 7q31.2 are paralogous regions within the human genome. Two splicing variants occur from human WNT2B gene due to alternative promoters. WNT2B splicing variant 1 encodes secreted-type glycoprotein with WNT domain (WNT2B isoform 1), while WNT2B splicing variant 2 encodes transmembrane-type glycoprotein with WNT domain (WNT2B isoform 2). WNT2B splicing variant 2 is the evolutionarily conserved major transcript of human WNT2B gene. Mammalian WNT2B orthologs acquired the transmembrane domain and integrin-targeting RGD motif during vertebrate evolution. Human WNT2B isoform 2 and other vertebrate WNT2B orthologs are canonical WNTs to determine cell fate through the activation of beta-catenin/TCF signaling pathway and SNAIL/EMT signaling pathway. E box and CCAAT box are conserved within mammalian WNT2B promoters. WNT2B functions as the stem cell factor for neural or retinal progenitor cells during embryogenesis, and also for gastric cancer, esophageal cancer and skin basal cell carcinoma during carcinogenesis. Anti-WNT2B monoclonal antibody could be applied as selection marker of stem cells in the field of stem cell biology. Soluble WNT2B protein or small molecule WNT2B mimic compounds could be developed for stem cell expansion in the fields of tissue engineering and regenerative medicine. Anti-WNT2B monoclonal antibodies, WNT2B RNAi compounds, or small molecule WNT2B inhibitors could be developed as novel therapeutic agents for gastric cancer and esophageal cancer in the field of clinical oncology.