The CBL Knockout K-562 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed for disruption of the CBL gene in the human chronic myelogenous leukemia cell line K-562. This loss-of-function model provides a powerful tool for dissecting the signaling networks regulated by CBL, an E3 ubiquitin-protein ligase that negatively controls receptor tyrosine kinase (RTK) cascades.
The host cell line, K-562, was established from the pleural effusion of a chronic myelogenous leukemia patient in blast crisis and harbors the Philadelphia chromosome, yielding the constitutively active BCR-ABL1 fusion kinase. As a pluripotent hematopoietic line with lymphoblast morphology and erythroid differentiation capacity, K-562 is widely employed to study leukemogenic signaling, erythroid differentiation, and therapeutic responses in myeloid malignancies.
CBL functions as an E3 ubiquitin ligase that targets activated RTKs??including EGFR, PDGFR, and c-Kit??for ubiquitination and subsequent degradation, thereby attenuating downstream signaling. It interacts with adaptor proteins such as Grb2 and CrkL, the regulatory p85 subunit of PI3K, and endocytic regulators like CIN85 and endophilin. Upon receptor activation, CBL is recruited by Src and Abl family kinases and mediates ubiquitin-dependent downregulation of key signaling intermediates. Loss of CBL leads to sustained activation of the RAS-MAPK/ERK pathway (via the EGFR/Grb2/SOS/RAS/RAF/MEK/ERK axis) and the PI3K/AKT/mTOR pathway (downstream of PDGFR and c-Kit), as well as persistent signaling through the T-cell receptor/ZAP70/LAT/PLC??1 module.
In the context of K-562 cells, which already harbor oncogenic BCR-ABL1 driving both MAPK and PI3K pathways, CBL knockout removes a critical brake on RTK signaling, potentially exacerbating proliferative and survival signals. This dual oncogenic insult makes the model especially relevant for studying the cooperativity between BCR-ABL1 and loss-of-function CBL mutations observed in aggressive myeloid disorders such as juvenile myelomonocytic leukemia (JMML) and chronic myelomonocytic leukemia (CMML). The cells exhibit enhanced apoptotic resistance and altered drug sensitivity profiles, offering a platform to dissect mechanisms of transformation and to identify synthetic lethal interactions.
Typical applications include functional investigations of CBL in leukemogenesis, analysis of BCR-ABL1?CRTK crosstalk, and pharmacological profiling of tyrosine kinase inhibitors. Users can assess pathway activation by western blotting for phospho-ERK, phospho-AKT, and phospho-Src; monitor cell cycle and apoptosis via flow cytometry (Annexin V staining); perform ubiquitination assays and co-immunoprecipitation to examine receptor degradation; and conduct colony-forming assays and drug sensitivity screens. This polyclonal knockout population is an invaluable resource for researchers exploring the molecular underpinnings of CBL-driven malignancies. For additional technical details or ordering information, please contact Ascent Research.
