The IBTK Knockout NCI-H1975 Polyclonal Cells represent a CRISPR/Cas9-engineered polyclonal knockout cell population derived from the human NCI-H1975 lung adenocarcinoma cell line, featuring targeted disruption of the IBTK gene. This polyclonal pool provides a heterogeneous loss-of-function model for studying IBTK-dependent signaling without clonal selection bias. The knockout product is supplied as a mixed population of edited cells, ensuring broad representation of functional consequences of IBTK ablation.
The NCI-H1975 cell line was established from a non-small cell lung adenocarcinoma and harbors activating EGFR L858R and resistance-conferring T790M mutations, making it a well-characterized model for EGFR-driven oncogenesis and acquired tyrosine kinase inhibitor (TKI) resistance. These cells exhibit adherent epithelial morphology and are widely used to investigate mechanisms of EGFR signaling, apoptosis resistance, and therapeutic response in lung cancer.
IBTK encodes the inhibitor of Bruton??s tyrosine kinase, a substrate recognition adaptor for the CUL3-RBX1 E3 ubiquitin ligase complex. Upon B-cell receptor (BCR) activation, IBTK interacts with CUL3 and RBX1 to recruit the E2 ubiquitin-conjugating enzymes, facilitating polyubiquitination and proteasomal degradation of downstream targets including Bruton??s tyrosine kinase (BTK) and IKZF1. This targeted degradation negatively modulates BCR-proximal signaling and attenuates downstream NF-??B pathway activation, as I??B?? degradation and subsequent nuclear translocation of p65/p50 NF-??B dimers are reduced. Transcriptional regulation of IBTK itself can be influenced by NF-??B activity, forming a feedback loop that fine-tunes BCR and NF-??B signaling outputs.
In the context of NCI-H1975 lung adenocarcinoma with oncogenic EGFR mutations, IBTK disruption facilitates investigation of ubiquitin-dependent regulatory mechanisms that intersect with pro-survival and apoptotic signaling. Although IBTK is classically positioned within BCR signaling cascades, its functional engagement with the CUL3-RBX1 ubiquitin ligase and NF-??B transcription factors is relevant for understanding how protein turnover influences the balance between proliferation and apoptosis in EGFR-driven tumors. The polyclonal knockout model allows researchers to interrogate how IBTK loss affects the stability of downstream substrates such as BTK and IKZF1, and how this might alter NF-??B-dependent gene expression programs, cytokine production, and chemosensitivity.
This knockout product enables study of the ubiquitin-proteasome-dependent regulation of NF-??B signaling by IBTK, using techniques such as co-immunoprecipitation of the CUL3-RBX1-IBTK complex, ubiquitination assays for BTK and IKZF1, and NF-??B luciferase reporter assays to quantify transcriptional activity. The polyclonal cells are suited for apoptosis profiling (e.g., annexin V staining), cell proliferation assays, and drug sensitivity screening, particularly in the presence of BTK inhibitors or EGFR TKIs, to uncover resistance mechanisms. For further information regarding lot-specific editing efficiency and validation, please contact Ascent Research.
