The B2M Knockout HCT 116 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population produced by targeted disruption of the B2M gene in the HCT 116 human colorectal carcinoma cell line. This polyclonal format comprises a diverse pool of edited cells, each carrying distinct mutations that collectively abrogate beta-2-microglobulin expression. As a population-based knockout model, it avoids the limitations of single-cell-derived clones and provides a versatile tool for functional studies under conditions that maintain cellular heterogeneity.
HCT 116 is a widely used epithelial cell line established from a human colorectal carcinoma with microsatellite instability-high (MSI-H) status. These cells harbor activating mutations in KRAS and PIK3CA, making them a relevant model for studying oncogenic signaling and tumor progression. HCT 116 cells retain an adherent morphology and are tumorigenic in immunocompromised mice, facilitating both in vitro and in vivo experimentation. Their genetic profile partially recapitulates the molecular alterations frequently observed in sporadic colorectal cancers, thereby providing a tractable system for dissecting cancer biology.
Beta-2-microglobulin (B2M) is the non-covalently bound light chain of MHC class I molecules (HLA-A, -B, -C). Its assembly in the endoplasmic reticulum requires chaperones calnexin, calreticulin, ERp57, and tapasin, and the peptide transporter TAP. Surface peptide-MHC I complexes present endogenous antigens to CD8+ T cells. B2M also interacts with the transferrin receptor (TFRC) to regulate iron uptake. B2M transcription is induced by IFN?? via STAT1 and IRF1, and by NF-??B and TNF??. Disruption of B2M eliminates surface MHC I, impairing CD8+ T cell recognition while potentially triggering NK cell cytotoxicity due to missing-self.
In HCT 116 cells, which are MSI-H and harbor KRAS and PIK3CA mutations, B2M knockout abrogates MHC class I-dependent antigen presentation, mirroring immune evasion strategies observed in colorectal tumors. This model enables dissection of how oncogenic signaling pathways intersect with immune recognition, and how loss of MHC I influences tumor cell sensitivity to NK cells and immunotherapy. The polyclonal nature preserves population heterogeneity, making it suitable for studying both clonal dynamics and bulk responses.
This B2M knockout model is suited for cancer immunology applications including T cell and NK cell cytotoxicity assays, validation of CAR-T and bispecific T-cell engagers, and screening for immune checkpoint inhibitors that may restore MHC I expression. Representative assays comprise flow cytometry for surface MHC class I, western blotting for B2M and HLA heavy chains, RT-qPCR, IFN?? stimulation, and co-culture with primary immune cells; in vivo xenograft studies can further evaluate tumor-immune interactions. For further assistance, contact Ascent Research.
