Lunatic Fringe Deficiency Cooperates with the Met/Caveolin Gene Amplicon to Induce Basal-like Breast Cancer

SummaryBasal-like breast cancers (BLBC) express a luminal progenitor gene signature. Notch receptor signaling promotes luminal cell fate specification in the mammary gland, while suppressing stem cell self-renewal. Here we show that deletion of Lfng, a sugar transferase that prevents Notch activation by Jagged ligands, enhances stem/progenitor cell proliferation. Mammary-specific deletion of Lfng induces basal-like and claudin-low tumors with accumulation of Notch intracellular domain fragments, increased expression of proliferation-associated Notch targets, amplification of the Met/Caveolin locus, and elevated Met and Igf-1R signaling. Human BL breast tumors, commonly associated with JAGGED expression, elevated MET signaling, and CAVEOLIN accumulation, express low levels of LFNG. Thus, reduced LFNG expression facilitates JAG/NOTCH luminal progenitor signaling and cooperates with MET/CAVEOLIN basal-type signaling to promote BLBC.

Graphical AbstractFigure optionsDownload full-size imageDownload high-quality image (182 K)Download as PowerPoint slideHighlights► Notch luminal fate and basal survival signals cooperate ► Lfng controls Notch activation in mammary stem and progenitor cells ► LFNG expression is consistently reduced in human basal-like breast cancer ► Lfng deletion cooperates with the Met/Cav amplicon to induce basal-like breast tumors