Non-Canonical Senescence Phenotype in Resistance to CDK4/6 Inhibitors in ER-Positive Breast Cancer.

ABSTRACT: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have transformed the treatment landscape for estrogen receptor-positive (ER+) breast cancer, yet resistance remains a major clinical challenge. Although CDK4/6i induce G₁ arrest and therapy-induced senescence (TIS), the exact nature of this senescent state and its contribution to resistance are not well understood. To explore this, we developed palbociclib- (2PR, 9PR, TPR) and abemaciclib- (2AR, 9AR, TAR) resistant ER+ breast cancer sublines through prolonged drug exposure over six months. Resistant cells demonstrated distinct phenotypic alterations, including cellular senescence, reduced mitochondrial membrane potential, and impaired glycolytic activity. Cytokine profiling and enzyme-linked immunosorbent assay (ELISA) validation

SUBMITTER: Mammadova A 

PROVIDER: S-EPMC12838639 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature