The CBLC Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population targeting the human CBLC gene. This product provides a loss-of-function model in the HAP1 cell line, a near-haploid human chronic myeloid leukemia-derived model. The use of polyclonal knockout cells offers a heterogeneous population with gene disruption, suitable for studying CBLC-dependent signaling pathways without the selection pressure of single-cell clones.
HAP1 cells are derived from the KBM-7 chronic myeloid leukemia cell line and possess a near-haploid karyotype, with the exception of a partial duplication of chromosome 15. They retain expression of the BCR-ABL fusion oncogene, a hallmark of chronic myeloid leukemia. The near-haploid genome simplifies genetic manipulation and facilitates CRISPR-based functional genomics screens, making HAP1 a widely adopted model for studying gene function, particularly in the context of cancer-relevant signaling pathways.
The CBLC gene encodes a member of the Cbl family of E3 ubiquitin-protein ligases, which function as negative regulators of receptor tyrosine kinase (RTK) signaling. CBLC is activated by upstream signals including EGF stimulation, EGFR, PDGFR, and SRC family kinase-mediated tyrosine phosphorylation. Once recruited to activated RTKs via adaptor proteins such as GRB2 and CIN85, CBLC cooperates with E2 conjugating enzymes UBE2L3 and UBE2D to catalyze ubiquitination of the receptor, targeting it for lysosomal degradation. This process attenuates downstream signaling through the RAS-RAF-MEK-ERK and PI3K-AKT pathways. Consequently, CBLC disruption leads to sustained phosphorylation of ERK and AKT, enhanced cell proliferation signals, and impaired receptor downregulation.
In the HAP1 cellular context, knockout of CBLC abolishes a critical negative feedback loop controlling RTK abundance and signaling. The BCR-ABL-positive background of HAP1 cells, which intrinsically activates PI3K-AKT and MAPK pathways, may interact with CBLC loss to further dysregulate signal transduction. This makes the CBLC knockout HAP1 polyclonal cells particularly relevant for dissecting the interplay between Cbl-mediated receptor degradation and oncogenic kinase signaling in myeloproliferative neoplasms and acute myeloid leukemia. Additionally, the near-haploid nature ensures that disruption of the single CBLC allele leads to complete loss of protein expression, enhancing the model’s utility for high-throughput screens and drug sensitivity assays.
Researchers can employ this polyclonal knockout cell population to investigate Cbl-dependent regulation of RTK signaling, with applications in cancer biology, functional genomics, and drug discovery. Typical experiments include western blot analysis of CBLC, EGFR, phospho-ERK, and phospho-AKT to confirm signaling perturbations, as well as EGFR degradation time-course assays and ubiquitination assays to assess receptor trafficking. Cell viability assays and RT-qPCR for downstream target genes provide complementary readouts for phenotypic and transcriptomic consequences of CBLC loss. This model is also suited for large-scale CRISPR modifier screens and for testing sensitivity to targeted therapeutics that rely on RTK degradation. For further information, please contact Ascent Research.
