1. Her2/neu extracellular domain shedding in uterine serous carcinoma: implications for immunotherapy with trastuzumab.
- Author
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Todeschini, P, Cocco, E, Bellone, S, Varughese, J, Lin, K, Carrara, L, Guzzo, F, Buza, N, Hui, P, Silasi, D-A, Ratner, E, Azodi, M, Schwartz, P E, Rutherford, T J, Pecorelli, S, and Santin, A D
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EPIDERMAL growth factor ,TRASTUZUMAB ,IMMUNOHISTOCHEMISTRY ,IN situ hybridization ,FLOW cytometry ,GENE amplification ,ANTIBODY-dependent cell cytotoxicity - Abstract
Background: We evaluated shedding of epidermal growth factor type II receptor (Her2/neu) extracellular domain (ECD) in primary uterine serous carcinoma (USC) cell lines and in the serum of USC patients and its biological effects in experiments of trastuzumab-induced cytotoxicity in vitro.Methods: Her2/neu expression was evaluated by immunohistochemistry (IHC), real-time PCR and flow cytometry, while c-erbB2 gene amplification was assessed using fluorescent in situ hybridisation (FISH). Her2/neu ECD levels in the supernatants of USC cell lines and in the serum of 38 USC patients and 19 controls were tested using ELISA. The biologic effect of Her2/neu ECD on trastuzumab-induced antibody-dependent cell-mediated cytotoxicity (ADCC) was evaluated in 5-h chromium-release assays.Results: Five out of ten USC cell lines overexpressed Her2/neu by IHC and showed amplification of the c-erbB2 gene. High levels of Her2/neu ECD were found in supernatants of all FISH-positive tumours. In contrast, FISH-negative USC was negative for Her2/neu ECD shedding. Serum Her2/neu ECD levels in patients harbouring 3+Her2/neu tumours were higher than those found in healthy women (P=0.02) or USC patients with 2+ or 1+/negative Her2/neu expression (P=0.02). In cytotoxicity experiments, trastuzumab-mediated ADCC was significantly decreased by the addition of Her2/neu ECD-containing supernatants (P=0.01).Conclusion: FISH-positive c-erbB2 USC cell lines shed high levels of Her2/neu ECD. High levels of Her2/neu ECD in USC patients may reduce trastuzumab-mediated ADCC in vitro and potentially neutralise its therapeutic effect in vivo. [ABSTRACT FROM AUTHOR]- Published
- 2011
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