The CBS Knockout K-562 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the CBS gene in the K-562 human cell line. This pooled population consists of cells with heterogeneous gene disruptions, providing a versatile loss-of-function model without clonal selection. The polyclonal format allows assessment of CBS disruption across a diverse genetic background, minimizing clonal artifacts and reflecting the complexity of heterogeneous tumor populations.
K-562 is a human chronic myelogenous leukemia (CML) cell line derived from the pleural effusion of a patient in blast crisis. This line harbors the Philadelphia chromosome, resulting in the BCR-ABL1 fusion oncogene, a hallmark of CML that drives uncontrolled proliferation and resistance to apoptosis. K-562 cells are widely utilized as a model system for erythroleukemia and myeloid differentiation, offering a robust platform for studying leukemogenesis, signal transduction, and therapeutic interventions in the context of constitutively active tyrosine kinase signaling.
CBS encodes cystathionine beta-synthase, a heme-dependent enzyme that catalyzes the condensation of homocysteine and serine to form cystathionine, the rate-limiting step of the transsulfuration pathway. This reaction is allosterically activated by S-adenosylmethionine (SAM) and regulated by heme, glucocorticoids, and transcription factors SP1 and NF-Y; SUMOylation modulates its activity and localization. CBS interacts with pyridoxal-5′-phosphate and the chaperonin CCT complex. Its product cystathionine is cleaved by cystathionine gamma-lyase (CTH) to generate cysteine, a precursor for glutathione and hydrogen sulfide (H2S). Thus, CBS sits at a hub connecting homocysteine clearance to redox balance and gasotransmitter synthesis.
In the K-562 leukemic background, disruption of CBS impairs transsulfuration, leading to homocysteine accumulation and decreased cysteine and glutathione pools. This compromises the cell??s ability to buffer oxidative stress and produce H2S, which is implicated in cytoprotection and proliferation in cancer. The CBS knockout K-562 polyclonal cells thus model the interplay between BCR-ABL1-driven signaling and metabolic reprogramming, especially reliance on transsulfuration-derived antioxidants for survival.
These knockout cells support a wide range of investigations, including homocysteine-mediated toxicity, redox homeostasis, and hydrogen sulfide signaling in leukemia. Typical applications utilize Western blot, RT-qPCR, ELISA or HPLC for homocysteine measurement, and fluorometric probes for H2S detection. They are also suitable for cell proliferation (MTT) and apoptosis (Annexin V/PI flow cytometry) assays under oxidative stress, drug sensitivity screens targeting transsulfuration, and mass spectrometry-based metabolomic profiling. For additional details, contact Ascent Research.
