The HCCS Knockout SK-HEP-1 Polyclonal Cells comprise a CRISPR/Cas9-edited polyclonal cell population derived from the SK-HEP-1 human liver adenocarcinoma line, in which the HCCS gene has been disrupted via CRISPR/Cas9-mediated genome editing. This polyclonal knockout model provides a genetically heterogeneous loss-of-function system, enabling the study of HCCS-dependent processes in a hepatic carcinoma background. The cells are suitable for investigating the functional consequences of HCCS ablation on mitochondrial respiration, cytochrome c maturation, and intrinsic apoptosis without the selection bias of clonal variants.
The parental SK-HEP-1 cell line is a widely utilized human hepatocellular carcinoma model of male, epithelial origin. It retains many characteristics of hepatocyte function and is frequently employed in liver cancer research, drug metabolism studies, and hepatic pathophysiology. The line??s tumorigenic properties, combined with its hepatic lineage, make it an ideal host for dissecting the intersection between mitochondrial bioenergetics and malignant transformation. SK-HEP-1 cells express key components of the oxidative phosphorylation pathway and apoptotic machinery, facilitating the assessment of HCCS-mediated phenotypes.
HCCS encodes holocytochrome c-type synthase, a mitochondrial heme lyase that catalyzes the covalent attachment of heme to apocytochrome c, a critical step in cytochrome c maturation. This conversion is essential for cytochrome c to function both as an electron carrier in respiratory chain complex IV and as a pro-apoptotic factor upon release into the cytosol. HCCS activity is regulated by transcription factors such as NRF1 and TFAM that coordinate mitochondrial biogenesis. Its primary direct interactant is cytochrome c (CYCS), and it cooperates with cytochrome c oxidase (COX) assembly factors to ensure proper incorporation into the electron transport chain. Downstream, mature cytochrome c facilitates electron shuttling between complex III and IV, while also binding Apaf-1 to activate Caspase-9 and initiate the intrinsic apoptosis cascade. Disruption of HCCS thus uncouples mitochondrial respiration from programmed cell death signaling.
In the SK-HEP-1 hepatocellular carcinoma background, HCCS knockout profoundly alters the cellular response to metabolic and apoptotic stimuli. Loss of functional HCCS impairs cytochrome c heme loading, diminishing cytochrome c oxidase activity and reducing oxidative phosphorylation efficiency, while simultaneously blunting caspase-mediated cell death. This dual deficiency is particularly relevant in liver cancer, where metabolic reprogramming and apoptosis evasion are hallmarks of disease progression. The model serves as a valuable tool for studying mitochondrial complex IV deficiency, cytochrome c-linked neurodegeneration, and the role of mitochondrial dysfunction in cancer metabolism. By leveraging the polyclonal population, researchers can examine heterogeneous adaptive mechanisms that arise upon HCCS ablation.
Researchers can employ these polyclonal knockout cells in a variety of assays to probe mitochondrial dysfunction. Western blot analysis of cytochrome c levels and SDS-PAGE-based detection of holocytochrome c formation provide direct measures of HCCS activity. Functional studies can include cytochrome c oxidase activity assays, caspase-3/9 activation profiling, and oxygen consumption rate (OCR) measurements to assess respiratory chain function. Mitochondrial membrane potential (????m) can be monitored via fluorescent dyes, while RT-qPCR for mitochondrial genes evaluates downstream transcriptional adaptations. This product supports investigations into mitochondrial disorders, apoptosis mechanisms, cancer metabolic rewiring, and drug screening for compounds that modulate mitochondrial fitness. For further information, please contact Ascent Research.
