title: Distinction of two different classes of small-cell lung cancer cell lines by enzymatically inactive neuron-specific enolase.
abstract: Neuron specific enolase (NSE) is widely used as a neuro-endocrine marker. However the presence of NSE in many non-neuroendocrine tissues has raised questions on the specificity of NSE. We have investigated NSE immunoreactivity (NSA-ag), gamma-enolase activity and total enolase activity in small cell lung cancer (SCLC) cell lines. During well-controlled exponential growth comparison of NSE-ag content and gamma-enolase activity with the doubling-time (Td) and NSE-ag content with gamma-enolase and total enolase activity led to a clear distinction of two types of cell line: variant cell lines plus part of the classic cell lines (type I) and the remaining classic cell lines (type II). The distinction was based upon both an abrupt 6-fold increase of gamma-enolase activity and an 18-fold increase of NSE-ag, which for the larger part was enzymatically inactive. Within each group the increase of NSE-ag content was significantly correlated with the increase of gamma-enolase activity and both NSE-ag content and gamma-enolase activity increased linearly with Td. It is concluded that gamma-enolase seems to be associated with the regulation of growth rate and that a compound with the gamma-enolase antigen but without enzyme activity can distinguish two different classes of SCLC cell lines. Furthermore the demonstration that NSE-ag can represent the active enzyme as well as an enzymatically inactive compound may explain why a controversy about neuron- or non-specificity of NSE exists.
authors.affiliation: Department of Medical Oncology, University Hospital, Rotterdam, The Netherlands.
authors.forename: T A
authors.initials: TA
authors.lastname: Splinter
authors.forename: C F
authors.initials: CF
authors.lastname: Verkoelen
authors.forename: M
authors.initials: M
authors.lastname: Vlastuin
authors.forename: T C
authors.initials: TC
authors.lastname: Kok
authors.forename: G
authors.initials: G
authors.lastname: Rijksen
authors.forename: K G
authors.initials: KG
authors.lastname: Haglid
authors.forename: F
authors.initials: F
authors.lastname: Boomsma
authors.forename: A
authors.initials: A
authors.lastname: van de Gaast
mesh_terms: D018288:Carcinoma, Small Cell / Q000145:classification / Q000201:enzymology* / Q000473:pathology; D002455:Cell Division; D006801:Humans; D010751:Phosphopyruvate Hydratase / Q000032:analysis*; D014407:Tumor Cells, Cultured / Q000201:enzymology / Q000473:pathology
chemical_list: D010751:Phosphopyruvate Hydratase