CRISPR/Cas9-mediated gene disruption of CASP8 in K-562 cells yields a polyclonal knockout cell population that serves as a comprehensive loss-of-function model for studying caspase-8 functions. This heterogeneous pool of edited cells enables robust analysis of death receptor signaling, apoptosis, and necroptosis without the limitations of clonal selection, making it suitable for diverse functional genomics applications.
The K-562 cell line is a human chronic myelogenous leukemia model derived from the pleural effusion of a 53-year-old female patient in blast crisis. It is characterized by the BCR-ABL1 fusion oncogene and possesses an erythroleukemic phenotype with potential for erythroid and myeloid differentiation. Widely utilized in leukemia research, K-562 cells provide a context of oncogene-driven survival signaling and intrinsic apoptosis resistance, offering a clinically relevant background for probing programmed cell death pathways.
CASP8 encodes caspase-8, an initiator caspase recruited to the death-inducing signaling complex (DISC) after binding of death ligands??FasL, TRAIL, or TNF-????to their respective receptors (Fas, DR4/DR5, TNFR1). Within the DISC, caspase-8 interacts with the adaptor FADD and is regulated by the inhibitor c-FLIP. Autoactivated caspase-8 cleaves executioner caspases-3 and -7, directly triggering apoptosis, and truncates BID, promoting mitochondrial cytochrome c release and caspase-9 activation. In conditions where apoptosis is blocked, caspase-8 participates in necroptosis through RIPK1 and RIPK3 phosphorylation. Additionally, caspase-8 modulates inflammatory responses via NF-kappa B and Toll-like receptor signaling.
Disruption of CASP8 in K-562 leukemic cells creates a powerful tool to dissect the dependency on extrinsic apoptosis pathways in the presence of BCR-ABL1-mediated survival signals. This model enables investigation of the molecular mechanisms that govern the switch between apoptosis and necroptosis and facilitates the identification of therapeutic strategies to overcome death receptor resistance in CML and other hematopoietic malignancies.
These polyclonal knockout cells are applicable in a variety of assays, including Western blot verification of CASP8 protein loss, RT-qPCR for transcript levels, and flow cytometry with Annexin V/PI staining following treatment with death receptor ligands such as TRAIL or anti-Fas. They further support caspase-8 activity measurements, co-immunoprecipitation of DISC components, necroptosis induction monitored by RIPK3 phosphorylation, and high-throughput screening of small-molecule modulators of death receptor signaling. For additional information or ordering details, please contact Ascent Research.
