The CASP3 Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population with targeted disruption of the CASP3 gene in the HAP1 human cell line. This loss-of-function model enables investigation of caspase-3, the key executioner caspase in apoptosis, within a near-haploid background. The polyclonal format provides a heterogeneous pool of gene-edited cells, avoiding clonal biases and facilitating robust functional genomics and drug screening applications.
HAP1 cells originate from the KBM-7 chronic myeloid leukemia (CML) line and maintain a near-haploid karyotype with single copies of most chromosomes. This genetic simplicity makes them ideal for knockout screens because disruption of one allele directly yields phenotypic effects. HAP1 cells exhibit adherent, fibroblast-like growth and stable signaling characteristics, widely used for studying cancer biology, drug responses, and apoptotic regulation.
CASP3 functions as an executioner caspase activated by proteolytic cleavage downstream of initiator caspases CASP8 and CASP9 in response to extrinsic or intrinsic apoptotic stimuli. Death receptors FAS or TNFRSF1A recruit FADD and CASP8, whereas mitochondrial cytochrome c release promotes APAF1-mediated CASP9 activation. Active CASP3 cleaves substrates such as PARP1, ICAD, ROCK1, and lamin A/C, driving DNA fragmentation, membrane blebbing, and cell shrinkage. Its activity is regulated by XIAP, survivin, and SMAC/DIABLO, and it interacts with BCL2 family proteins, p53, and granzyme B. Caspase-3 also amplifies the apoptotic cascade by processing BID and procaspases.
In the HAP1 CML background, CASP3 disruption allows dissection of apoptosis mechanisms relevant to leukemia and drug resistance. The near-haploid state simplifies genetic analysis, making these cells suitable for systematic screens to identify pathways that bypass caspase-3 dependence. Researchers can probe the interplay between BCR-ABL signaling, p53 status, and apoptotic execution, revealing potential therapeutic vulnerabilities in CML and other cancers.
Applications include apoptosis pathway analysis, cancer drug response profiling, and high-throughput knockout screens. Validated assays for these cells include Western blot for cleaved CASP3, caspase-3 activity measurements, and PARP cleavage assays to confirm loss of function. Phenotypic consequences can be assessed by Annexin V/PI flow cytometry, TUNEL staining, and cell viability assays. The polyclonal nature also supports genome-wide CRISPR modifier screens to uncover alternative cell death mechanisms. For further assistance or custom applications, please contact Ascent Research.
