The physiological functions of
butyrylcholinesterase (BChE) and its role in
malignancy remain unexplained. Our studies in children newly diagnosed with
neuroblastoma indicated that BChE expressions is proportional to MYCN amplification suggesting that pathogenesis of high-risk disease may be related to the persistent expression of abnormally high levels of
tumor-associated BChE. BChE-deficient
neuroblastoma cells (KO [knockout]) were produced from MYCN -amplified BE(2)-C cells (WT [wild-type]) by the CRISPR-Cas9 targeted disruption of the BCHE locus. KO cells have no detectable BChE activity. The compensatory
acetylcholinesterase activity was not detected. The average population doubling time of KO cells is 47.0±2.4 hours, >2× longer than WT cells. Reduced proliferation rates of KO cells were accompanied by the loss of
N-Myc protein and a significant deactivation of
tyrosine kinase receptors associated with the aggressive
neuroblastoma phenotype including Ros1, TrkB, and Ltk. Tumorigenicity of WT and KO cells in male mice was essentially identical. In contrast, KO xenografts in female mice were very small (0.37±0.10 g), ~3× smaller compared with WT xenografts (1.11±0.30 g). Unexpectedly, KO xenografts produced changes in plasma BChE similarly to WT
tumors but lesser in magnitude. The disruption of BCHE locus in MYCN -amplified
neuroblastoma cells decelerates proliferation and produces
neuroblastoma cells that are less aggressive in female mice.