C61
The Wnt signalling pathway and regulation of breast cancer stem-like cells
Rebecca Lamb, Robert Clarke
The University of Manchester, Manchester, UK
There is evidence that breast cancers contain tumourgenic stem-like cells and that de-regulation of their self-renewal plays a role in disease development. Accumulating data suggests a role of the Wnt pathway in breast cancer therefore we aimed to investigate Wnt expression and its role in stem-like cells.
Using qRT-PCR, we investigated the expression of 26 Wnt pathway genes using 5 immortalised normal, 6 oestrogen receptor-alpha (ER)-positive, and 5 ER-negative breast cancer cell lines. We identified several statistically significant differences (P≤ 0.05): Upregulation of Wnt targets AXIN2, WISP2 and LEF1 and a decrease in WNT10A and the Wnt inhibitor DKK1 were observed in breast cancer compared to normal cell lines. ER-positive cell lines had decreased WNT5a, WNT5b, WISP1, LBH and SFRP1 compared to ER-negative.
MCF7 breast cancer cells were cultured using non-adherent conditions which enrich for self-renewing stem-like cells growing as mammospheres (MS). MS harvested after 1, 4 and 7 days had increased Wnt activation compared to cells cultured in adherent conditions. We therefore used DKK1 to inhibit Wnt signalling in MCF7 cells and showed a significant reduction in MS formation (P≤ 0.05).
Our data suggest that the Wnt pathway plays an important role in breast cancer and that Wnt signalling regulates breast cancer stem-like cell self-renewal.
