The CD320 Knockout NCI-H1975 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal cell population derived from the NCI-H1975 human lung adenocarcinoma cell line, engineered for disruption of the CD320 gene. This loss-of-function model targets the transcobalamin receptor, crucial for cellular uptake of vitamin B12 (cobalamin) bound to transcobalamin II. The polyclonal format provides a heterogeneous knockout pool, avoiding clonal selection artifacts while enabling robust investigation of CD320-dependent mechanisms. The product is designed for advanced biomedical research applications, including metabolic studies and cancer biology.
The host NCI-H1975 cell line is a well-established model of non-small cell lung cancer (NSCLC), originating from a lung adenocarcinoma with documented EGFR T790M/L858R mutations. It is extensively utilized in drug resistance and signaling research, exhibiting metabolic reprogramming characteristic of tumor cells. The lung adenocarcinoma background offers a physiologically relevant system to examine cobalamin metabolism and its perturbations in a malignant epithelial context, making it suitable for dissecting vitamin B12’s role in cancer cell proliferation and survival.
At the molecular level, CD320 functions as a high-affinity receptor for transcobalamin II (TCN2), mediating clathrin-dependent endocytosis of the TCN2-cobalamin complex. Post-internalization, lysosomal degradation releases cobalamin, which acts as an essential cofactor for methionine synthase (MTR) and methylmalonyl-CoA mutase (MUT). MTR catalyzes homocysteine remethylation to methionine, connecting to folate-dependent one-carbon metabolism and nucleotide synthesis, while MUT converts methylmalonyl-CoA to succinyl-CoA in odd-chain fatty acid and branched-chain amino acid catabolism. Thus, CD320 is an upstream regulator of these critical enzymes, with its disruption impairing both cytosolic and mitochondrial cobalamin-dependent pathways, potentially altering homocysteine levels and methylmalonic acid accumulation.
In the NCI-H1975 context, CD320 knockout is expected to attenuate cobalamin uptake, leading to diminished methionine synthase and methylmalonyl-CoA mutase activities, which may compromise one-carbon metabolism and energy production. This could affect DNA methylation, glutathione synthesis, and cell cycle progression, highlighting the interplay between vitamin B12 homeostasis and lung adenocarcinoma biology. The model permits targeted investigation of metabolic vulnerabilities in NSCLC, offering insights into how transcobalamin receptor deficiency influences tumor cell fitness and response to nutrient-restricted environments.
Researchers can employ this polyclonal knockout population in a diverse array of assays, including radiolabeled cobalamin uptake experiments to quantify transport efficiency, methylmalonic acid quantification via LC-MS or enzymatic methods, methionine synthase activity assays, western blotting to verify CD320 loss, and cell proliferation studies in vitamin B12-depleted media to assess metabolic dependency. The model is particularly relevant for exploring methylmalonic aciduria, transcobalamin receptor deficiency, and cobalamin metabolic roles in cancer, as well as for conducting genetic or pharmacological rescue experiments. For more information, please contact Ascent Research.
