TRAF4 promotes tumorigenesis of breast cancer through activation of Akt

Increasing evidence suggests that tumor necrosis factor receptor-associated factor 4 (TRAF4) is an oncogene which is frequently overexpressed in many human carcinomas. Although TRAF4 was originally identified in breast cancer, the underlying mechanism of TRAF4 in tumorigenesis remains largely unknown. In the present study, we found that TRAF4 was overexpressed in cancer cells, and RNA interference (RNAi)-mediated gene knockdown of TRAF4 decreased cell growth, cell migration and invasion. Next, we found that TRAF4 promoted cell survival kinase Akt membrane recruitment, which is essential for Akt activation. Furthermore, we demonstrated a direct interaction between Akt and TRAF4. Additionally, overexpression of constitutively activated Akt reversed cell growth arrest in TRAF4 gene-silenced cells. Taken together, our data indicate that TRAF4 plays an important role in tumorigenesis of breast cancer through direct interaction and activation of Akt, implying that TRAF4 may be a potential molecular target for breast cancer prevention and therapy.