DOC-2/hDab-2 inhibits ILK activity and induces anoikis in breast cancer cells through an Akt-independent pathway

DOC-2/hDab-2 was identified due to the loss of its expression in primary ovarian cancer cells. It is believed that loss of DOC-2/hDab-2 expression is one of the early events of ovarian malignancy. These results suggest a function of DOC-2/hDab-2 as a tumor suppressor. However, it is not clear how DOC-2/hDab-2 negatively regulates cancer cell growth. In this report, we demonstrate that DOC-2/hDab-2 expression in breast cancer cells resulted in sensitivity to suspension-induced cell death (anoikis). This event was associated with the down-regulation of the integrin-linked kinase (ILK) activity. Since ILK is a key factor in regulating the cellular signaling in responding to the extracellular signals through adhesion molecules like integrins, our results indicate that DOC-2/hDab-2 may prevent tumor growth and invasion by modulating the anti-apoptotic ILK pathway.