The CBS Knockout 786-O Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the CBS gene in the 786-O human renal adenocarcinoma cell line. This polyclonal population contains a heterogeneous mix of cells with diverse editing events at the target locus, avoiding the clonal biases associated with single-cell-derived lines. By abolishing CBS expression, these cells provide a versatile loss-of-function model for investigating transsulfuration-dependent processes without the limitations of monoclonal selection. Researchers can leverage this tool to examine population-level effects on sulfur amino acid metabolism, hydrogen sulfide signaling, and associated redox dynamics.
The 786-O host cell line originates from a primary clear cell renal cell carcinoma and serves as a well-characterized epithelial renal carcinoma model. These cells are deficient in the von Hippel-Lindau (VHL) tumor suppressor, leading to constitutive stabilization of hypoxia-inducible factor 1-alpha (HIF-1alpha) and mimicking the pseudohypoxic state common in clear cell renal carcinomas. The adherent epithelial morphology and well-documented genetic background make 786-O cells a robust platform for studying metabolic vulnerabilities, drug responses, and tumorigenic signaling in renal cancer research.
CBS encodes cystathionine beta-synthase, a pyridoxal phosphate-dependent enzyme that condenses homocysteine and serine to produce cystathionine, the committing step of the transsulfuration pathway. This reaction, allosterically activated by S-adenosylmethionine, directs methionine-derived sulfur toward cysteine biosynthesis and generates the gasotransmitter hydrogen sulfide (H2S). CBS functions upstream of cystathionine gamma-lyase (CTH) and interacts with heme as a regulatory cofactor. The enzyme is transcriptionally controlled by SP1 and HIF-1alpha, placing it at the intersection of one-carbon metabolism, oxygen sensing, and cellular stress responses. Downstream, CBS activity influences cysteine availability, glutathione synthesis, and protein persulfidation.
Knocking out CBS in the 786-O background disrupts the transsulfuration pathway, blocking cystathionine and cysteine production and severely attenuating H2S release. Given the VHL-deficient, HIF-1alpha-active context, this model enables dissection of how renal carcinoma cells adapt to impaired sulfur amino acid metabolism and altered redox homeostasis. The loss of CBS-dependent sulfide signaling may impact mitochondrial function, cell proliferation, and survival under nutrient-depleted conditions, revealing potential metabolic liabilities that could be exploited therapeutically in clear cell renal cell carcinoma.
These polyclonal knockout cells are suited for diverse experimental approaches, including western blotting and RT-qPCR for CBS validation, metabolomic profiling of homocysteine and cystathionine, H2S detection with fluorescent probes, and viability assays under cysteine deprivation. Additional applications encompass glutathione measurement, proliferation and migration studies, and proteomic analysis of protein sulfhydration. Such investigations advance understanding of transsulfuration-driven tumor biology, redox regulation, and H2S-mediated signaling. For further information, please contact Ascent Research.
