The CASP8 Knockout SK-HEP-1 Polyclonal Cells product provides a CRISPR/Cas9-edited polyclonal knockout population targeting the CASP8 gene in the human SK-HEP-1 hepatic adenocarcinoma cell line. This loss-of-function model enables investigation of caspase-8, an initiator caspase that governs extrinsic apoptosis, necroptosis suppression, and inflammatory signaling. The polyclonal format delivers a heterogeneous genetic background with robust target gene disruption, suitable for studying complex cell death pathways and regulatory networks.
The host SK-HEP-1 cell line was derived from the ascitic fluid of a 52-year-old male with liver adenocarcinoma and displays both endothelial/mesenchymal and carcinoma characteristics. This dual phenotype renders it a relevant model for hepatocellular carcinoma biology, endothelial-like features, and cancer cell plasticity. SK-HEP-1 cells are widely utilized in liver cancer research, including studies on drug resistance, metastasis, and vascular mimicry, establishing an appropriate platform for dissecting caspase-8-dependent mechanisms in a tumor context.
Caspase-8 functions as an initiator caspase activated downstream of death receptors Fas and TRAIL-R1/2 upon ligand binding (FasL, TRAIL). Recruitment of FADD and procaspase-8 to the DISC triggers auto-cleavage and activation, cleaving executioner caspases CASP3 and CASP7 to induce apoptosis. Additionally, caspase-8 proteolytically targets RIPK1 and RIPK3, suppressing necroptosis, and regulates NF-??B signaling and IL-1?? processing. Interactions with c-FLIP, TRADD, and ARC further shape cell fate decisions. Consequently, CASP8 disruption abolishes death receptor-mediated apoptosis and relieves necroptosis inhibition, permitting RIPK1-RIPK3-MLKL-driven necroptotic death, while perturbing inflammatory pathways, offering insight into cell death crosstalk.
In the SK-HEP-1 cell background, CASP8 knockout ablates extrinsic apoptosis, conferring resistance to TRAIL- and FasL-induced killing. The absence of caspase-8 predisposes these polyclonal cells to RIPK1/RIPK3-dependent necroptosis, particularly under conditions that block apoptosis or trigger necroptosis. This model enables dissection of apoptosis-necroptosis balance in liver cancer, assessment of therapeutic necroptosis induction, and investigation of caspase-8-independent inflammatory processes like NF-??B signaling and pyroptosis. It is highly relevant for probing cell death resistance mechanisms in hepatocellular carcinoma and for identifying compounds that drive tumor cells toward immunogenic necroptotic demise.
Research applications encompass detailed apoptosis signaling dissection using Western blot for CASP8, cleaved caspases, and DISC components; cell viability and death mode discrimination via Annexin V/PI flow cytometry with TRAIL or anti-Fas agonists; necroptosis induction and validation with necrostatin-1 rescue; caspase-8 activity assays; RT-qPCR for transcriptional targets; and co-immunoprecipitation to examine complex formation. The polyclonal population is also well-suited for genetic screens, drug response profiling, and mechanistic studies of inflammatory pathways intersecting with cell death. For further details, please contact Ascent Research.
