Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Breast cancer is genetically heterogeneous, and recent studies have underlined a prominent contribution of epigenetics to the development of this disease. To uncover new synthetic lethalities with known breast cancer oncogenes, we screened an epigenome-focused short hairpin RNA library on a panel of engineered breast epithelial cell lines. Here we report a selective interaction between the NOTCH1 signaling pathway and the SUMOylation cascade. Knockdown of the E2-conjugating enzyme UBC9 (UBE2I) as well as inhibition of the E1-activating complex SAE1/UBA2 using ginkgolic acid impairs the growth of NOTCH1-activated breast epithelial cells. We show that upon inhibition of SUMOylation NOTCH1-activated cells proceed slower through the cell cycle and ultimately enter apoptosis. Mechanistically, activation of NOTCH1 signaling depletes the pool of unconjugated small ubiquitin-like modifier 1 (SUMO1) and SUMO2/3 leading to increased sensitivity to perturbation of the SUMOylation cascade. Depletion of unconjugated SUMO correlates with sensitivity to inhibition of SUMOylation also in patient-derived breast cancer cell lines with constitutive NOTCH pathway activation. Our investigation suggests that SUMOylation cascade inhibitors should be further explored as targeted treatment for NOTCH-driven breast cancer.

Original publication




Journal article



Publication Date





3780 - 3790


Apoptosis, Blotting, Western, Breast Neoplasms, Cell Cycle, Cell Line, Cell Line, Tumor, Cell Proliferation, Coculture Techniques, Flow Cytometry, Gene Expression Regulation, Neoplastic, Humans, Microscopy, Fluorescence, RNA Interference, Receptor, Notch1, Reverse Transcriptase Polymerase Chain Reaction, SUMO-1 Protein, Salicylates, Signal Transduction, Small Ubiquitin-Related Modifier Proteins, Sumoylation, Transcriptional Activation, Ubiquitin-Activating Enzymes, Ubiquitin-Conjugating Enzymes, Ubiquitins