The GUSB Knockout HCT 116 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population engineered for disruption of the GUSB gene in the HCT 116 human colorectal carcinoma epithelial cell line. This polyclonal population provides a heterogeneous loss-of-function model for studying beta-glucuronidase deficiency without clonal selection, enabling robust functional screening and pooled analysis. The knockout cells are generated using CRISPR/Cas9-mediated genome editing to introduce targeted gene disruption, offering a versatile tool for pharmacological and genetic investigations of lysosomal metabolism and glycosaminoglycan degradation pathways.
HCT 116 is a widely studied epithelial cell line derived from a male patient with colorectal carcinoma. The cells harbor KRAS G13D and PIK3CA mutations, are mismatch repair proficient, and retain wild-type p53, features that reflect key oncogenic drivers and genomic stability profiles observed in colorectal tumors. This genetic background makes HCT 116 a relevant model for dissecting tumor biology, drug metabolism, and prodrug activation in a colorectal carcinoma context. The availability of this GUSB knockout background in HCT 116 facilitates examination of lysosomal function in transformed colonic epithelia.
The GUSB gene encodes beta-glucuronidase, a lysosomal acid hydrolase that catalyzes the hydrolytic removal of glucuronic acid residues from the non-reducing termini of glycosaminoglycans such as dermatan sulfate, heparan sulfate, and chondroitin sulfate, as well as from steroid glucuronides. Biochemically, beta-glucuronidase activity is essential for the stepwise degradation of complex carbohydrates within lysosomes and for the reactivation of glucuronidated hormones and xenobiotics. The enzyme is transcriptionally regulated by upstream factors including the androgen receptor, TFEB, and Sp1, and its intracellular trafficking and catalytic function depend on interactions with the mannose-6-phosphate receptor, the protective protein cathepsin A, and the sphingolipid activator saposin B. Within the broader glycosaminoglycan degradation network, GUSB operates alongside lysosomal hydrolases such as IDUA, SGSH, NAGLU, ARSB, GALNS, and GLB1, whose coordinated actions are necessary for complete substrate processing. Loss of GUSB activity disrupts this cascade, leading to accumulation of partially degraded glycosaminoglycan fragments that engage downstream pathological mechanisms.
Disruption of GUSB in HCT 116 cells recapitulates the lysosomal storage pathology characteristic of mucopolysaccharidosis type VII (Sly syndrome), a disorder marked by the buildup of partially catabolized glycosaminoglycans in lysosomes. In the context of colorectal carcinoma, this knockout model allows investigators to explore how lysosomal dysfunction intersects with oncogenic KRAS and PIK3CA signaling. Because beta-glucuronidase participates in the reactivation of glucuronidated hormones and the deconjugation of drug metabolites, the GUSB-deficient HCT 116 model is particularly relevant for studying hormone reactivation in colorectal cancer and for evaluating cytochrome P450?Cdependent drug metabolism pathways that yield glucuronide conjugates. The retention of wild-type p53 and mismatch repair proficiency further permits studies of lysosomal stress responses and genomic integrity in a defined cancer genetic background.
This polyclonal knockout cell product supports diverse research applications, including mucopolysaccharidosis type VII disease modeling, lysosomal storage disorder investigation, and drug metabolism studies focusing on glucuronide prodrug activation. Researchers can employ enzymatic activity assays using fluorogenic substrates to confirm GUSB deficiency, quantify glycosaminoglycan accumulation via the dimethylmethylene blue (DMMB) binding assay, and assess protein expression changes by Western blotting and immunofluorescence for lysosomal markers. Cell viability assays with glucuronide prodrugs enable functional screening of compounds that rely on beta-glucuronidase?Cmediated activation, while RT-qPCR provides transcriptional profiling of pathway components. For detailed technical specifications, protocols, or ordering information, please contact Ascent Research.
