The CBL Knockout 786-O Polyclonal Cells are a heterogeneous population of 786-O human renal clear cell carcinoma epithelial cells with CRISPR/Cas9-mediated disruption of the CBL gene. Generated through pooled transfection and selection, these polyclonal knockout cells contain a mixture of editing outcomes. As a polyclonal population, they are not clonally derived and do not guarantee biallelic knockout. The cells provide a physiologically relevant loss-of-function model for studying CBL-dependent signaling in a cancer cell context.
The 786-O host cell line was derived from a primary clear cell renal adenocarcinoma of a 58-year-old male. It harbors an inactivating VHL mutation, making it a widely used model for clear cell renal cell carcinoma (ccRCC). The VHL loss leads to constitutive HIF pathway activation, promoting tumorigenic properties. Introducing CBL knockout into this VHL-mutant background creates a compound genetic model for dissecting cooperative signaling events in renal cancer.
CBL encodes an E3 ubiquitin-protein ligase that negatively regulates receptor tyrosine kinase (RTK) signaling. Activated by upstream receptors including EGFR and MET, CBL is recruited via adaptors GRB2 and SHC and promotes ubiquitination of these RTKs with E2 enzymes such as UBE2D1, targeting them for lysosomal degradation. This terminates downstream cascades, notably MAPK/ERK (MAPK1/3) and PI3K-AKT (AKT1). CBL also ubiquitinates non-receptor kinases like SRC and SYK. Through these interactions, CBL serves as a critical brake on proliferative and survival signaling.
In 786-O cells, CBL knockout disrupts this negative regulation, likely sustaining RTK signaling. Combined with the VHL mutation that already elevates HIF-driven growth factor secretion, CBL loss may amplify EGFR-MAPK/ERK and PI3K-AKT pathways, enhancing proliferation, migration, and drug resistance. This compound model is valuable for studying the interplay of two tumor suppressors frequently altered in ccRCC, and is particularly suited for investigating resistance to TKIs targeting EGFR or MET.
This polyclonal knockout product enables a variety of assays. Researchers can compare ubiquitination and degradation of EGFR or MET via ubiquitination assays and co-immunoprecipitation. Signaling outputs can be measured by western blotting for phospho-EGFR, phospho-AKT, and phospho-ERK1/2. Functional studies include proliferation (MTT, BrdU), migration/invasion, and cell cycle analysis by flow cytometry. Drug sensitivity testing with tyrosine kinase inhibitors can elucidate CBL’s role in therapeutic response. For inquiries, contact Ascent Research.
