The BLM Knockout HCT 116 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population carrying BLM gene disruption in the HCT116 human colorectal carcinoma cell line. This heterogeneous loss-of-function model avoids clonal selection bias, facilitating robust assessment of BLM-dependent phenotypes. CRISPR/Cas9-mediated disruption abolishes BLM helicase activity, providing a tool for studying genome maintenance and cancer biology.
The parental HCT116 line is an epithelial colorectal carcinoma with a KRAS G13D mutation, MLH1 deficiency, and MSI-H phenotype, while retaining wild-type p53. This background promotes mismatch repair-driven mutagenesis and impaired DNA damage signaling, creating a permissive environment for DNA repair interaction studies. HCT116 cells are widely used in cancer research owing to their genetic stability and reproducible growth, making them a reliable host for knockout generation.
BLM encodes a RecQ DNA helicase that maintains genome stability by unwinding complex DNA substrates during replication and repair. It functions within the BLM-TOP3A-RMI1-RMI2 complex to resolve Holliday junctions, suppress sister chromatid exchanges, and ensure chromosome segregation. Upstream regulators ATM and ATR activate BLM in response to DNA breaks and replication stress, while BLM cooperates with BRCA1, RAD51, and FANCD2 in homologous recombination. BLM also interacts with MLH1 and EXO1 during mismatch repair and with WRN for telomere maintenance. Knockout abrogates these activities, causing recombination intermediate accumulation, elevated sister chromatid exchanges, and chromosomal instability.
In the HCT116 background, BLM disruption synergizes with MLH1 deficiency and MSI-H to further destabilize the genome, accelerating mutation accumulation and replication stress. This combinatorial defect mimics aspects of Bloom syndrome and recapitulates concurrent mismatch repair and helicase deficiencies in colorectal cancers. The polyclonal population retains the KRAS G13D oncogenic driver, enabling studies of oncogene-induced replication stress and synthetic lethality with DNA repair inhibitors. Accordingly, this model is valuable for exploring therapeutic vulnerabilities in MSI-H colorectal cancers with BLM loss, particularly sensitivity to PARP inhibitors.
Researchers employ this polyclonal knockout product for DNA repair pathway dissection, genomic instability research, and preclinical drug sensitivity screening. Suitable assays include sister chromatid exchange, comet assay, ??H2AX immunofluorescence/flow cytometry, homologous recombination reporters, DNA fiber analysis, and colony formation under drug treatment. This model also supports synthetic lethality screens and chemosensitivity testing with PARP inhibitors, replication stress inducers, and other chemotherapeutics, aiding identification of new strategies for DNA repair-deficient cancers. For further details and ordering information, please contact Ascent Research.
