The CASP8 Knockout 786-O Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the CASP8 gene encoding caspase-8 in the human 786-O renal cell carcinoma cell line. This polyclonal knockout model provides a loss-of-function system for studying caspase-8-dependent signaling mechanisms in an epithelial tumor background. By using CRISPR/Cas9-mediated gene disruption, the product enables researchers to investigate the roles of caspase-8 without the need for transient knockdown approaches, offering a stable and versatile tool for in vitro functional assays.
The 786-O cell line is derived from a primary clear cell adenocarcinoma of the kidney and is a widely used model for clear cell renal cell carcinoma (ccRCC). These cells harbor a VHL mutation, reflecting the frequent loss of von Hippel-Lindau tumor suppressor function in ccRCC, which leads to constitutive stabilization of hypoxia-inducible factors (HIFs) and altered signaling networks. The adherent epithelial morphology and well-characterized genetic background of 786-O make it suitable for apoptosis, necroptosis, and drug response studies, particularly in the context of kidney cancer biology.
Caspase-8, encoded by CASP8, is an initiator caspase critical for death receptor-mediated apoptosis. Upon ligation of death receptors such as Fas, TRAIL, or TNF-alpha, caspase-8 is recruited to the death-inducing signaling complex (DISC) via the adaptor FADD, where it undergoes dimerization and autocatalytic activation. Active caspase-8 directly cleaves downstream effector caspases, including caspase-3 and caspase-7, and also cleaves the Bcl-2 family member BID to truncated BID (tBID), which engages the mitochondrial apoptotic pathway by promoting cytochrome c release. Beyond apoptosis, caspase-8 participates in necroptosis through interactions with RIPK1 and RIPK3, and modulates inflammatory signals from Toll-like receptors and RIG-I-like receptors. Regulatory factors such as c-FLIP and TRAF2 modulate caspase-8 activity.
In the 786-O ccRCC model, CASP8 knockout provides a valuable tool to dissect the contributions of caspase-8 to cell death and survival pathways often dysregulated in renal cancer. Since VHL loss can influence apoptotic sensitivity and necroptotic signaling, the absence of caspase-8 in this genetic background allows researchers to evaluate compensatory mechanisms, resistance to TRAIL or FasL-induced apoptosis, and the interplay between extrinsic apoptosis and HIF-driven pathways. This polyclonal knockout population avoids clonal artifacts, enabling the study of heterogeneous responses and the identification of subpopulation-specific vulnerabilities.
Typical applications include apoptosis and necroptosis studies using assays such as Annexin V staining and cell viability measurements with necroptosis inhibitors. The knockout cells are suitable for high-content screening of caspase-8 modulators, co-immunoprecipitation experiments examining DISC formation, and western blotting to validate downstream target cleavage, including caspase-3 and BID processing. Additionally, these cells can be employed in renal cell carcinoma drug resistance studies, where caspase-8 function is often linked to chemotherapeutic sensitivity. Researchers may use flow cytometry to assess death receptor-induced cell death and explore crosstalk between apoptosis and inflammatory signaling pathways. For further information or assistance, please contact Ascent Research.
