A CRISPR/Cas9-edited polyclonal CD44 knockout cell population has been generated using the DLD-1 human colorectal adenocarcinoma cell line. This polyclonal pool disrupts CD44 gene function, providing a loss-of-function model that avoids clonal selection bias and preserves genetic heterogeneity. The knockout is suitable for population-level studies of CD44-dependent signaling and phenotypic alterations in a colorectal cancer context.
DLD-1 is an adherent epithelial-like cell line derived from a Duke’s type C colorectal adenocarcinoma. It is extensively used in cancer research due to its well-characterized genetic background, including mutations in APC, TP53, and KRAS. These features make DLD-1 an appropriate model for investigating colorectal tumor biology, metastasis, and therapeutic responses.
CD44 is a transmembrane receptor for extracellular matrix components such as hyaluronic acid (HA), osteopontin, and collagens. Ligand binding recruits ERM adaptor proteins (ezrin, radixin, moesin) and ankyrin, linking CD44 to the cytoskeleton and activating Src and PI3K. This triggers PI3K/Akt and MAPK/ERK signaling, promoting proliferation, survival, and migration. CD44 expression is stimulated by TNF-??, IL-1??, TGF-??, EGF, HGF, and transcription factors NF-??B and AP-1, and inhibited by p53. Downstream, CD44 upregulates MMP-9, uPA, Cyclin D1, Bcl-2, and mesenchymal markers Snail, Twist, Zeb1, N-cadherin, and vimentin, facilitating epithelial-mesenchymal transition.
In DLD-1 colorectal cancer cells, CD44 contributes to cancer stem cell maintenance, EMT, and metastasis. Its knockout disrupts the HA/CD44/ERM/Src/PI3K/Akt cascade, likely reducing Akt and ERK phosphorylation and suppressing invasion-related proteases such as MMP-9. Because DLD-1 cells have constitutive Wnt/??-catenin activity due to APC mutation, this model enables study of cross-talk between CD44-mediated adhesion signals and Wnt signaling in colorectal cancer progression.
Applications include colorectal cancer metastasis research, cancer stem cell biology, EMT studies, and evaluation of CD44-targeted therapies. Representative assays encompass western blotting and flow cytometry for knockout validation and signaling analysis (e.g., phospho-Akt, phospho-ERK), scratch wound healing and Transwell invasion assays for migration/invasion, cell adhesion assays for HA binding, colony formation and spheroid culture for clonogenicity, and drug sensitivity testing for chemoresistance. Transcriptomic profiling via RT-qPCR or RNA-seq can identify CD44-dependent gene programs. For further information, contact Ascent Research.
