The HMOX1 Knockout DLD-1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal cell population derived from the human colorectal adenocarcinoma cell line DLD-1. This product features targeted disruption of the HMOX1 gene, which encodes heme oxygenase-1, through CRISPR/Cas9-mediated gene editing. The polyclonal format provides a heterogeneous knockout pool, enabling robust and reproducible loss-of-function studies in an isogenic background. Researchers can use this model to interrogate the role of HMOX1 in cellular stress responses and tumor biology without the clonal variation inherent in single-cell?Cderived lines. The cells are suitable for a broad range of in vitro assays including gene expression analysis, enzymatic activity measurement, and phenotype-based screens.
DLD-1 is a well-characterized human colorectal adenocarcinoma cell line originally isolated from a primary tumor. This adherent epithelial line is widely used in colorectal cancer research due to its defined genetic landscape, which includes pathogenic mutations in APC, TP53, and KRAS??three of the most frequently altered genes in sporadic colorectal carcinogenesis. The DLD-1 model recapitulates key aspects of tumor progression, such as dysregulated Wnt/??-catenin signaling, defective DNA damage response, and constitutive MAPK pathway activation. Consequently, DLD-1 serves as a versatile platform for investigating molecular mechanisms driving colorectal tumorigenesis, metastasis, and therapeutic resistance. The isogenic HMOX1 knockout variant allows direct comparison with wild-type DLD-1 cells, facilitating dissection of HMOX1-dependent phenotypes.
HMOX1 catalyzes the rate-limiting step in heme degradation, cleaving the porphyrin ring to yield equimolar amounts of biliverdin, carbon monoxide (CO), and free iron. This enzymatic activity places HMOX1 at the nexus of multiple cellular processes. Under basal conditions, HMOX1 expression is low but is potently induced by a variety of stress stimuli, including oxidative stress, heme overload, and inflammatory cytokines. The transcriptional induction is primarily governed by the antioxidant transcription factor NRF2, which dissociates from KEAP1 and binds to antioxidant response elements (AREs) in the HMOX1 promoter, while BACH1 acts as a transcriptional repressor under non-stressed conditions. Additional upstream regulators include HIF1A under hypoxia, and pro-inflammatory mediators such as IL6 and lipopolysaccharide. Once induced, HMOX1 exerts cytoprotective effects through its reaction products: biliverdin is rapidly reduced to bilirubin by biliverdin reductase, and both biliverdin and bilirubin act as potent lipid-soluble antioxidants; CO at low concentrations signals through soluble guanylyl cyclase and MAPK pathways to promote anti-inflammatory, anti-apoptotic, and vasodilatory responses; labile iron released during heme catabolism upregulates the iron storage protein ferritin, which sequesters redox-active iron and attenuates Fenton chemistry. HMOX1 interacts directly with cytochrome P450 reductase (POR) for electron transfer and functionally cooperates with BACH1 and NRF2 to maintain redox homeostasis. Downstream targets of HMOX1-mediated signaling include enhanced expression of ferritin, the anti-apoptotic protein BCL2, and the anti-inflammatory cytokine IL10, collectively underpinning its role in cellular resilience.
In the DLD-1 colorectal adenocarcinoma background, HMOX1??s antioxidant and anti-inflammatory functions may significantly influence tumor cell fate. Colorectal cancer cells often experience elevated oxidative stress due to metabolic rewiring and inflammation, and HMOX1 induction can promote survival, proliferation, and evasion of apoptosis, potentially contributing to a malignant phenotype. The presence of mutant TP53 in DLD-1 cells may intersect with HMOX1-mediated cytoprotection, as wild-type p53 has been shown to repress HMOX1 expression. Moreover, KRAS-driven signaling can enhance NRF2 activity, leading to sustained HMOX1 expression and adaptation to oxidative stress. By simultaneously disrupting the APC, TP53, and KRAS pathways in the context of HMOX1 deficiency, this knockout model allows researchers to dissect the interplay between oncogenic signaling and redox regulation. Studies employing this system can clarify whether HMOX1 operates as a tumor suppressor in early stages or as a facilitator of tumor progression and resistance in advanced colorectal cancer.
This knockout cell population is engineered for diverse experimental applications. It serves as a critical tool for investigating HMOX1-dependent responses to oxidative stress, ferroptosis, and inflammatory stimuli. Researchers can measure heme oxygenase enzyme activity, quantify bilirubin production, and assess intracellular reactive oxygen species (ROS) levels using fluorescent probes. The model is well suited for evaluating the impact of HMOX1 loss on cell proliferation, apoptosis, and ferroptosis induction, including lipid peroxidation analysis following glutathione depletion or GPX4 inhibition. Additionally, the cells enable studies on drug resistance mechanisms, as HMOX1 has been implicated in chemoresistance in colorectal cancer. Transwell migration and invasion assays can be employed to probe HMOX1??s role in metastasis, while NRF2/ARE reporter systems can delineate transcriptional regulation of the HMOX1 locus. Western blotting and RT-qPCR serve to confirm target gene disruption and monitor downstream signaling events. For further information on this HMOX1 knockout model or related products, please contact Ascent Research.
