Differential Expression of Wnts, β-catenin and E-cadherin in hEFs and Normal, Abnormal Karyotype hES Cells during Culture in vitro

Human embryonic fibroblasts （hEFs） can well maintain the pluripotency in human embryonic stem cells （hESs）. However, recent research and reports indicated that a few of hES cell lines acquired genomic alteration during long-term culture of hES cells in vitro. This will directly restrict the therapy use of hES cells. Wnts are secreted lipid-modified signaling proteins that influence multiple processes ranging from cell proliferation to stem cell loss. Activation of Wnt signaling in many tissues has also been associated with cancer. Unchecked Wnt signaling and loss of cadherin expression can promote tumorigenesis. In this study, we found the caryotype of one hES cell line chHES-3 changed with duplication of 1 p32-1p36 area after 34 passages. The results of RT-PCR indicated Wnt7a was expressed in hEFs after culture normal karyotype hES cells, but not expressed in control and abnormal karyotype hES cells. Wnt3 was expressed in hEFs after culture abnormal karyotype hES cells, not expressed in control and normal karyotype hES cells. Wnt3, Wnt9a and WntlOb were detected weakly expression in normal hES cells, but higher in abnormal hES cells. At the same time, Wnt3a, Wnt4, Wnt5b, Wnt7a, Wnt8b and Wnt11 were expressed and E-cadherin was not tested in abnormal hES cells compared with normal hES cells. All that indicated Wnt7a was need for culture normal karyotype hES cells and Wnt3 was need for culture abnormal karyotype hES cells on hEFs. Wnt3, Wnt9a and WntlOb high expression in hES cells and absence of E-cadherin may cause hES cells karyotype change.