The CBS Knockout HT29 Polyclonal Cells constitute a CRISPR/Cas9-edited polyclonal knockout cell population in which the gene encoding cystathionine beta-synthase (CBS) has been disrupted in the human HT29 colorectal adenocarcinoma cell line. This loss-of-function model enables researchers to interrogate the transsulfuration pathway within an intestinal epithelial context. By eliminating functional CBS expression, the cells offer a powerful tool for studying homocysteine metabolism, hydrogen sulfide (H2S) production, and downstream effects on redox homeostasis and sulfur amino acid utilization. The polyclonal nature of the knockout pool preserves the genetic heterogeneity inherent to cancer cell populations, providing a physiologically relevant background for dissecting CBS-dependent phenotypes without clonal selection artifacts.
HT29 cells are derived from a human colorectal adenocarcinoma and are widely employed as a model of intestinal epithelial biology. They exhibit an adherent, epithelial-like morphology and retain features of enterocytic differentiation, such as the expression of brush-border enzymes and mucins under appropriate culture conditions. This cell line is a cornerstone in colorectal cancer research, offering a robust platform for investigating tumor cell signaling, metabolic adaptation, and responses to therapeutic agents. The HT29 genetic background carries mutations in APC, TP53, and PI3KCA, among others, which recapitulate key oncogenic drivers, rendering it an ideal host for evaluating the contribution of CBS to cancer-associated metabolic reprogramming.
CBS catalyzes the condensation of homocysteine and serine to form cystathionine, a pivotal step in the transsulfuration pathway that ultimately generates cysteine, glutathione, taurine, and the gasotransmitter H2S. The enzyme is allosterically activated by S-adenosylmethionine (SAM) and requires heme as a cofactor, while its expression is regulated by the transcription factor SP1 and responds to oxidative stress and homocysteine levels. CBS-derived H2S exerts signaling functions through protein persulfidation and modulation of nitric oxide (NO) bioavailability, impacting processes such as angiogenesis, inflammation, and cellular bioenergetics. Downstream of CBS, cystathionine is further metabolized by cystathionine gamma-lyase (CSE) to yield cysteine, feeding into glutathione synthesis and taurine production, thus linking the methionine cycle to antioxidant defenses.
In the context of HT29 colorectal cancer cells, CBS occupies a critical nexus integrating sulfur metabolism with tumor cell behavior. Elevated homocysteine and altered transsulfuration flux have been associated with colorectal cancer progression and hyperhomocysteinemia-related cardiovascular risk. By ablating CBS, this knockout model permits direct assessment of how loss of enzymatic activity reshapes intracellular homocysteine and H2S pools, perturbing redox balance, proliferation, and metastatic potential. It allows researchers to disentangle the dual roles of H2S as a pro-survival signal and a cytoprotective molecule, clarifying its context-dependent effects on apoptosis, migration, and invasion in colorectal adenocarcinoma.
Research applications for the CBS Knockout HT29 Polyclonal Cells are broad and mechanistically focused. They are ideally suited for targeted metabolomics using LC-MS to profile changes in homocysteine, cystathionine, cysteine, and glutathione levels, and for validating H2S production via methylene blue or fluorescent probe assays. Functional studies can incorporate cell proliferation, apoptosis, and transwell migration/invasion assays to correlate CBS status with malignant phenotypes. The model serves as a valuable substrate for drug screening efforts aimed at transsulfuration pathway modulators, and for exploring the interplay between one-carbon metabolism and colorectal cancer biology. For technical inquiries and further details, please contact Ascent Research.
