Persistent Activation of NF-?B in BRCA1-Deficient Mammary Progenitors Drives Aberrant Proliferation and Accumulation of DNA Damage.

ABSTRACT: Human BRCA1 mutation carriers and BRCA1-deficient mouse mammary glands contain an abnormal population of mammary luminal progenitors that can form 3D colonies in a hormone-independent manner. The intrinsic cellular regulatory defect in these presumptive breast cancer precursors is not known. We have discovered that nuclear factor kappaB (NF-?B) (p52/RelB) is persistently activated in a subset of BRCA1-deficient mammary luminal progenitors. Hormone-independent luminal progenitor colony formation required NF-?B, ataxia telangiectasia-mutated (ATM), and the inhibitor of kappaB kinase, IKK?. Progesterone (P4)-stimulated proliferation resulted in a marked enhancement of DNA damage foci in Brca1(-/-) mouse mammary. In vivo, NF-?B inhibition prevented recovery of Brca1(-/-) hormone-independent colony-forming cells. The majority of human BRCA1(mut/+) mammary glands showed marked lobular expression of nuclear NF-?B. We conclude that the aberrant proliferative capacity of Brca1(-/-) luminal progenitor cells is linked to the replication-associated DNA damage response, where proliferation of mammary progenitors is perpetuated by damage-induced, autologous NF-?B signaling.

SUBMITTER: Sau A 

PROVIDER: S-EPMC6850408 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature