CBL Knockout A-549 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal cell population derived from the A-549 human lung adenocarcinoma cell line, engineered for loss-of-function studies of the CBL gene. This knockout model disrupts CBL expression across a heterogeneous cell pool, providing a valuable tool for investigating the functional consequences of CBL deficiency in a cancer-relevant epithelial background. The polyclonal nature maintains genetic diversity while enabling consistent ablation of the target gene, making it suitable for population-based functional assays without the clonal selection artifacts often encountered in monoclonal knockout lines.
The parental A-549 cell line was established from the lung adenocarcinoma of a 58-year-old Caucasian male and exhibits an adherent epithelial morphology with molecular features of alveolar type II cells. Notably, A-549 cells harbor wild-type KRAS and EGFR alleles, which is particularly advantageous for dissecting CBL-dependent signaling because it avoids confounding mutations in these major oncogenic drivers. This wild-type status ensures that observed phenotypic changes following CBL knockout primarily reflect the loss of CBL regulatory function rather than epistatic interactions with pre-existing activating mutations.
CBL encodes an E3 ubiquitin-protein ligase that acts as a critical negative regulator of receptor tyrosine kinase (RTK) signaling. Upon growth factor stimulation, CBL is rapidly recruited to activated receptors such as EGFR, MET, and PDGFRA through its interaction with adaptor proteins including GRB2, CRK, and NCK. CBL then catalyzes the conjugation of ubiquitin, often in collaboration with UBE2D-family E2 enzymes, leading to receptor ubiquitination, endocytosis, and lysosomal degradation. This process effectively attenuates signal transduction downstream of RTKs. CBL also interacts with CIN85 and CD2AP to facilitate receptor internalization, and its activity is regulated by upstream kinases such as SRC and FYN. Disruption of CBL therefore results in sustained activation of downstream effectors like PI3K p85, SRC, and in immunological contexts, SYK and ZAP70, thereby enhancing cell proliferation and survival signals.
The A-549 CBL knockout model holds particular significance for lung adenocarcinoma research. Because CBL functions as a tumor suppressor in certain settings, its inactivation can potentiate oncogenic RTK output in the absence of activating receptor mutations. This polyclonal knockout population enables researchers to model CBL loss-of-function scenarios that may parallel genetic lesions observed in myelodysplastic syndromes and juvenile myelomonocytic leukemia, and can be applied to investigate how CBL deficiency cooperates with other molecular alterations in driving malignant phenotypes in lung epithelial cells. Given that A-549 cells are EGFR wild-type, this model is also an ideal platform for examining mechanisms of primary resistance to EGFR tyrosine kinase inhibitors, where enhanced receptor stability due to CBL loss may undermine drug efficacy.
This knockout product supports a wide range of experimental applications, including detailed signaling studies using EGF stimulation followed by Western blot analysis of phospho-EGFR and downstream targets, ubiquitination assays by immunoprecipitation of EGFR and anti-ubiquitin detection, and quantitative RT-PCR for CBL mRNA analysis. Functional assays such as MTS/MTT proliferation, transwell migration/invasion, and flow cytometry for EGFR surface expression can be used to assess phenotypic endpoints. Moreover, the polyclonal cells are well-suited for RNA-seq-based transcriptional profiling and synthetic lethality screens aimed at identifying vulnerabilities unique to CBL-deficient lung cancer cells. For technical specifications and ordering details, please contact Ascent Research.
