Soluble EpCAM levels in ascites correlate with positive cytology and neutralize catumaxomab activity in vitro.
BMC Cancer
; 15: 372, 2015 May 07.
Article
em En
| MEDLINE
| ID: mdl-25947366
ABSTRACT
BACKGROUND:
EpCAM is highly expressed on membrane of epithelial tumor cells and has been detected as soluble/secreted (sEpCAM) in serum of cancer patients. In this study we established an ELISA for in vitro diagnostics to measure sEpCAM concentrations in ascites. Moreover, we evaluated the influence of sEpCAM levels on catumaxomab (antibody)--dependent cellular cytotoxicity (ADCC).METHODS:
Ascites specimens from cancer patients with positive (C+, n = 49) and negative (C-, n = 22) cytology and ascites of patients with liver cirrhosis (LC, n = 31) were collected. All cell-free plasma samples were analyzed for sEpCAM levels with a sandwich ELISA system established and validated by a human recombinant EpCAM standard for measurements in ascites as biological matrix. In addition, we evaluated effects of different sEpCAM concentrations on catumaxomab-dependent cell-mediated cytotoxicity (ADCC) with human peripheral blood mononuclear cells (PBMNCs) and human tumor cells.RESULTS:
Our ELISA showed a high specificity for secreted EpCAM as determined by control HEK293FT cell lines stably expressing intracellular (EpICD), extracellular (EpEX) and the full-length protein (EpCAM) as fusion proteins. The lower limit of quantification was 200 pg/mL and the linear quantification range up to 5,000 pg/mL in ascites as biological matrix. Significant levels of sEpCAM were found in 39% of C+, 14% of C- and 13% of LC ascites samples. Higher concentrations of sEpCAM were detectable in C+ (mean 1,015 pg/mL) than in C- (mean 449 pg/mL; p = 0.04) or LC (mean 326 pg/mL; p = 0.01). Soluble EpCAM concentration of 1 ng/mL significantly inhibited ADCC of PBMNCs on EpCAM overexpressing target cells.CONCLUSION:
Elevated concentrations of sEpCAM can be found in a subgroup of C+ and also in a small group of C- patients. We consider that sEpCAM levels in different tumor entities and individual patients should be evaluated prior to applying anti-EpCAM antibody-based cancer therapies, since sEpCAM neutralizes catumaxomab activity, making therapy less efficient.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ascite
/
Moléculas de Adesão Celular
/
Anticorpos Biespecíficos
/
Antígenos de Neoplasias
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
BMC Cancer
Assunto da revista:
NEOPLASIAS
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Áustria