The HBP1 Knockout NCI-H1975 Polyclonal Cells provide a CRISPR/Cas9-mediated loss-of-function model in a polyclonal format, derived from the NCI-H1975 human lung adenocarcinoma cell line. This population contains a spectrum of HBP1 edits, facilitating pooled studies that avoid clonal selection bias. The polyclonal nature is particularly advantageous for drug response profiling and signaling pathway interrogation, where cellular heterogeneity more accurately mirrors in vivo tumor conditions.
The parental NCI-H1975 line originates from a female non-smoker with lung adenocarcinoma and carries activating EGFR mutations (L858R and T790M). These mutations drive constitutive kinase activity and confer resistance to first-generation EGFR TKIs but retain susceptibility to third-generation agents such as osimertinib. Consequently, NCI-H1975 is a standard model for studying acquired resistance mechanisms in EGFR-mutant NSCLC, making it an optimal host for investigating the functional interplay between tumor suppressor inactivation, Wnt pathway activation, and TKI responsiveness.
HBP1 (HMG-box transcription factor 1) functions as a transcriptional repressor and tumor suppressor, critically inhibiting Wnt/??-catenin signaling. It directly interacts with LEF/TCF transcription factors??such as LEF1 and TCF7L2??and recruits corepressor complexes containing HDAC1 to repress target genes like CCND1 (cyclin D1) and MYC, thereby restraining cell cycle progression. HBP1 can also induce CDKN1A (p21) and CDKN2A (p16), reinforcing cell cycle arrest and senescence programs. Its expression and activity are controlled by upstream regulators including E2F, p53, TGF-??, and Wnt ligands, establishing intricate feedback mechanisms that govern the equilibrium between proliferation and growth suppression.
Disruption of HBP1 in NCI-H1975 cells is predicted to derepress Wnt/??-catenin signaling, leading to upregulation of proliferative drivers CCND1 and MYC, heightened proliferation, and possibly diminished sensitivity to EGFR inhibitors. Given that aberrant Wnt pathway activation constitutes a recognized resistance mechanism in EGFR-mutant NSCLC, this knockout model enables dissection of how HBP1 loss cooperates with oncogenic EGFR signaling to promote aggressive tumor behavior. Moreover, it allows assessment of cellular responses to osimertinib and Wnt pathway inhibitors, potentially revealing synergistic therapeutic vulnerabilities.
The HBP1 Knockout NCI-H1975 Polyclonal Cells support a broad array of research applications, from characterizing Wnt pathway deregulation in EGFR-mutant adenocarcinoma to evaluating the tumor-suppressive roles of HBP1 and probing drug resistance paradigms. Key assays include quantitative western blotting for CCND1 and MYC, RT-qPCR analysis of Wnt targets (e.g., AXIN2), TOP/FOP Flash reporter assays for ??-catenin-driven transcription, MTT-based proliferation and colony formation assays, Annexin V apoptosis detection, and dose-response studies with osimertinib or selective Wnt inhibitors. RNA-sequencing can further map genome-wide transcriptional alterations consequent to HBP1 loss. For additional information or technical support, please contact Ascent Research.
