A Noncanonical Role of Fructose-1, 6-Bisphosphatase 1 Is Essential for Inhibition of Notch1 in Breast Cancer.

Breast cancer is a leading cause of death in women worldwide, but the underlying mechanisms of breast tumorigenesis remain unclear. Fructose-1, 6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis, was recently shown to be a tumor suppressor in breast cancer. However, the mechanisms of FBP1 as a tumor suppressor in breast cancer remain to be explored. Here we showed that FBP1 bound to Notch1 in breast cancer cells. Moreover, FBP1 enhanced ubiquitination of Notch1, further leading to proteasomal degradation via FBXW7 pathway. In addition, we found that FBP1 significantly repressed the transactivation of Notch1 in breast cancer cells. Functionally, Notch1 was involved in FBP1-mediated tumorigenesis of breast cancer cells in vivo and in vitro. Totally, these findings indicate that FBP1 inhibits breast tumorigenesis by regulating Notch1 pathway, highlighting FBP1 as a potential therapeutic target for breast cancer. IMPLICATIONS: We demonstrate FBP1 as a novel regulator for Notch1 in breast cancer. ©2020 American Association for Cancer Research.