NOTCH1 gene amplification promotes expansion of Cancer Associated Fibroblast populations in human skin

ABSTRACT: Cancer associated fibroblasts (CAFs) represent a key component of the tumor microenvironment. Possible genomic alterations in these cells remain a point of contention. The skin is constantly exposed to clastogenic insults, such as UVA light that can target directly the stromal compartment, therefore representing a relevant model to study. Here we report that CAFs from skin Squamous Cell Carcinoma (SCC) lesions display chromosomal alterations, with heterogeneous levels of NOTCH1 gene amplification that also occur, to a lesser extent, in dermal fibroblasts of apparently unaffected skin. The fraction of the latter cells harboring NOTCH1 gene amplification is expanded by chronic UVA exposure, which induces a DNA damage response (DDR) to which CAFs are resistant. The selective advantage conferred by NOTCH1 gene amplification and over-expression can be explained by NOTCH1 ability to block DDR-mediated growth arrest through competitive suppression of ATM-FOXO3a association and downstream signaling cascade. These findings are of translational significance as, in an orthotopic model of skin SCC, genetic or pharmacological inhibition of NOTCH1 activity suppresses cancer / stromal cells expansion. Thus, NOTCH1 amplification and increased expression contribute to CAFs evolution and are an attractive target for preventing cancer / stromal cell expansion.

ORGANISM(S): Homo sapiens

PROVIDER: GSE113577 | GEO | 2020/08/25

REPOSITORIES: GEO