The EFEMP1 Knockout 786-O Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population generated through targeted disruption of the EFEMP1 gene in the human 786-O renal cell carcinoma cell line. This heterogeneous knockout pool provides a robust loss-of-function model for investigating the role of fibulin-3 (EFEMP1) in extracellular matrix biology and tumor cell behavior. As a polyclonal population, it retains genetic diversity while uniformly lacking functional EFEMP1 expression, enabling studies that do not require clonal homogeneity. The cells are designed for researchers seeking to interrogate EFEMP1-dependent mechanisms in a well-characterized VHL-deficient kidney cancer background without the selection bias inherent in single-cell clones.
The parental 786-O cell line is derived from a primary clear cell renal cell carcinoma and harbors a natural VHL gene mutation, leading to constitutive activation of hypoxia-inducible factor (HIF) pathways under normoxic conditions. This genetic feature makes 786-O a cornerstone model for studying pseudohypoxic signaling, angiogenesis, and tumor progression in kidney cancer. The cells exhibit an epithelial morphology and are widely used to investigate renal carcinoma biology, including the response to hypoxia-driven gene expression programs and targeted therapeutics. The VHL-deficient background is particularly relevant for examining how extracellular and intracellular cues converge to regulate tumorigenic properties.
EFEMP1 encodes fibulin-3, a secreted extracellular matrix glycoprotein that mediates cell adhesion, migration, and proliferation. It acts as a contextual regulator of the TGF-?? and Wnt signaling pathways, interacting with integrin ??V??3, fibronectin, and tropoelastin to modulate focal adhesion dynamics and ECM integrity. Upstream, EFEMP1 expression is transactivated by SP1 and HIF-1?? in response to TGF-??1 and hypoxic stress, while epigenetic silencing via promoter methylation has been observed in some tumors. Downstream, EFEMP1 influences the expression of p53 and p21, suppresses MMP-2 and MMP-9 activity, and inhibits pro-survival cascades such as PI3K/AKT and MAPK/ERK, ultimately leading to reduced VEGF production and attenuated angiogenesis. Through these mechanisms, EFEMP1 functions as a putative tumor suppressor by restraining aberrant growth factor signaling and matrix remodeling.
In 786-O cells, disruption of EFEMP1 is predicted to release key restraints on oncogenic signaling, given the cell’s VHL-mutant background. Loss of fibulin-3 may enhance HIF-1??-driven transcriptional programs, augment TGF-??-mediated invasion, and reduce apoptosis through diminished p53 and caspase activation. This knockout model thus provides a valuable platform to dissect how the ECM component fibulin-3 integrates with hypoxic and cytokine-dependent pathways to modulate clear cell renal cell carcinoma aggressiveness. The polyclonal format is especially suited for functional screens, drug-response profiling, and studies requiring a population-level representation of EFEMP1 loss, mimicking heterogeneous tumor environments.
Researchers can employ these polyclonal knockout cells in a broad array of applications, including in vitro assays such as Boyden chamber migration/invasion, extracellular matrix adhesion, apoptosis detection via annexin V flow cytometry, and phospho-signaling analysis of AKT and ERK. In vivo, the cells are suitable for xenograft tumor growth studies to assess tumor initiation and progression, as well as angiogenesis assays using conditioned medium in tube formation experiments. The model also supports transcriptomic profiling by RNA-seq and protein interaction analyses by co-immunoprecipitation of known EFEMP1 binding partners like fibulin-1 and TIMP-3. These applications collectively enable comprehensive investigation of fibulin-3 function in renal cancer and beyond. For additional information or to explore custom modifications, please contact Ascent Research.
