The BRCA1 Knockout MDA-MB-231 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal knockout cell population originating from the MDA-MB-231 human breast adenocarcinoma line. These polyclonal knockout cells carry a spectrum of heterogeneous BRCA1 gene disruptions, resulting in a diverse collection of loss-of-function alleles. This population-based format eliminates clonal selection artifacts and provides a physiologically relevant model for investigating BRCA1 deficiency within a mixed genetic context, mirroring the heterogeneity of BRCA1-mutated cancers.
MDA-MB-231 is a triple-negative breast cancer (TNBC) cell line established from a pleural effusion of a metastatic mammary adenocarcinoma. It is ER-negative, PR-negative, and HER2-negative, with mutations in TP53, KRAS (G13D), and BRAF (G464V). The cells display a highly invasive, mesenchymal-like phenotype, making them an excellent platform for examining TNBC biology and BRCA1-dependent processes in a clinically relevant genetic background.
BRCA1 is a tumor suppressor central to homology-directed repair of DNA double-strand breaks. Upon DNA damage, ATM/ATR kinases phosphorylate BRCA1, promoting its interaction with BARD1. The BRCA1-BARD1 complex facilitates RAD51 loading and strand invasion, while also regulating cell cycle checkpoints via p53 and transcriptional targets. Interacting proteins include BRCA2, PALB2, CtIP, and BACH1; downstream effectors encompass 53BP1, p21, and GADD45. Loss of BRCA1 disrupts these functions, causing reliance on error-prone repair and genomic instability.
In the MDA-MB-231 background, BRCA1 knockout eliminates homologous recombination capacity, creating a synthetic lethal vulnerability to PARP inhibitors such as olaparib. Combined with p53 deficiency, this leads to heightened genomic instability and increased invasive potential, mirroring features of BRCA1-mutated breast cancers. The model is thus a valuable tool for dissecting DNA damage response networks and evaluating targeted therapies.
Applications include DNA repair and synthetic lethality studies using clonogenic survival, RAD51 foci immunofluorescence, and flow cytometric cell cycle analysis. Researchers employ this model for PARP inhibitor sensitivity testing, drug resistance profiling, and analysis of the Fanconi anemia pathway. The polyclonal population is particularly suited for high-throughput screens, RNA-seq, and chromatin architecture assays. For further details and technical support, please contact Ascent Research.
