title: Effect of eosinophil cationic protein (ECP) on Hodgkin lymphoma cell lines.
abstract: OBJECTIVE
  In Hodgkin lymphoma (HL), tumor eosinophilia indicates poor prognosis, probably caused by eosinophil-induced stimulation of tumor cells. Our aim was to investigate the effects of eosinophil cationic protein (ECP) on HL tumor cells in vitro.
  
  
  METHODS
  A fluorometric microculture cytotoxicity assay was used to measure the survival index of cells from the HL cell lines: HDLM-2 (T-cell origin, nodular sclerosis histology), KMH2 (B-cell origin, mixed cellularity), and L428 (B-cell origin, nodular sclerosis) after incubation with ECP97arg variants with different glycosylations and with ECP97thr. Flow cytometry monitored the effects of ECP on markers of cell death.
  
  
  RESULTS
  For KMH2 and L428, ECP was cytotoxic with a dose-response relationship similar to a previously investigated small-cell lung cancer cell line. HDLM-2 was more sensitive to ECP at low concentrations, but reached a plateau (survival index of 70%) at 0.018 μM. The IC(50) for KMH2 and L428 were 0.2 and 0.15 μM, respectively. The IC(50) was never reached for HDLM-2. All tested ECP variants displayed similar activity in HDLM-2, in contrast to KMH2 and L428, which were more sensitive to less glycosylated ECP. Positive DNA staining (propidium iodide) of HDLM-2 cells treated with ECP indicated cell death by necrosis.
  
  
  CONCLUSIONS
  ECP is cytotoxic for HL tumor cells even at low concentrations, but heterogeneity between cell lines exists and not all tumor cells are eradicated. Two cell lines of B-cell origin, KMH2 and L428, were sensitive to ECP in a dose-response manner, but for HDLM-2, which is of T-cell origin, the cytotoxicity reached a plateau.
authors.affiliation: Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden. Ingrid.Glimelius@onkologi.uu.se
authors.forename: Ingrid
authors.initials: I
authors.lastname: Glimelius
authors.forename: Jenny
authors.initials: J
authors.lastname: Rubin
authors.forename: Marie
authors.initials: M
authors.lastname: Fischer
authors.forename: Daniel
authors.initials: D
authors.lastname: Molin
authors.forename: Rose-Marie
authors.initials: RM
authors.lastname: Amini
authors.forename: Per
authors.initials: P
authors.lastname: Venge
authors.forename: Gunilla
authors.initials: G
authors.lastname: Enblad
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D047150:Eosinophil Cationic Protein / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004804:Eosinophils / Q000378:metabolism*; D005434:Flow Cytometry; D006031:Glycosylation; D006689:Hodgkin Disease / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020128:Inhibitory Concentration 50; D017730:Ki-1 Antigen / Q000378:metabolism; D008970:Molecular Weight; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D017730:Ki-1 Antigen; D047150:Eosinophil Cationic Protein