The CD44 Knockout NCI-H1975 Polyclonal Cells are a genetically engineered cell population derived from the human lung adenocarcinoma NCI-H1975 cell line, modified via CRISPR/Cas9-mediated disruption of the CD44 gene. This polyclonal knockout product comprises a heterogeneous mixture of cells, each carrying gene-editing events within the CD44 locus, establishing a loss-of-function model without clonal isolation. The CD44 knockout impairs expression of the corresponding transmembrane glycoprotein, enabling functional interrogation of CD44-dependent cellular processes in a non-small cell lung cancer background.
The host NCI-H1975 cell line is an epithelial model of human lung adenocarcinoma harboring endogenous EGFR L858R and T790M mutations, which confer constitutive kinase activity and resistance to first-generation EGFR tyrosine kinase inhibitors. This dual-mutant background is widely employed to investigate mechanisms of acquired drug resistance, tumor progression, and metastasis in NSCLC. NCI-H1975 cells exhibit robust invasive and migratory capacities, making them particularly suitable for studying the contributions of adhesion receptors like CD44 to aggressive cancer phenotypes.
CD44 functions as a transmembrane glycoprotein receptor for hyaluronan (HA) and osteopontin (OPN), transducing signals that regulate adhesion, migration, and survival. Ligand binding recruits ERM proteins (ezrin, radixin, moesin) to link CD44 to the actin cytoskeleton and promotes co-receptor interactions with EGFR and c-Met, thereby activating PI3K/Akt, MAPK/ERK, NF-??B, and Rho GTPase cascades. CD44 expression and activity are modulated by cytokines (TNF-??, TGF-??) and growth factors (EGF) and are stabilized under hypoxic conditions via HIF-1??. Key downstream effectors include the transcription factors Snail and Twist, MMP-9, Akt, and ERK, which collectively orchestrate epithelial-mesenchymal transition (EMT), cell motility, and matrix degradation. CD44 also contributes to ??-catenin stabilization, reinforcing Wnt pathway signaling.
In the context of EGFR-mutant lung adenocarcinoma, CD44 has been associated with enhanced metastatic dissemination and reduced sensitivity to EGFR-targeted agents. The NCI-H1975 knockout model allows precise dissection of CD44-mediated signaling networks that underlie EMT, matrix degradation, and chemoresistance. By eliminating CD44 expression, researchers can assess alterations in hyaluronan binding, cytoskeletal reorganization, and downstream phosphorylation events, thereby clarifying the receptor’s contribution to the aggressive behavior of this NSCLC subtype.
This knockout polyclonal cell model enables functional studies of CD44 in lung adenocarcinoma, including migration/invasion (Transwell), hyaluronan binding, and western blot analysis of phospho-Akt and phospho-ERK. It supports flow cytometric verification of CD44 ablation, RT-qPCR of EMT markers (Snail, Twist, MMP-9), and viability assays with EGFR inhibitors to examine drug resistance. These applications facilitate target validation and mechanism-of-action studies. For further information, please contact Ascent Research.
