Bellone S, Roque D, Cocco E, Gasparrini S, Bortolomai I, Buza N, Abu-Khalaf M, Silasi DA, Ratner E, Azodi M, Schwartz PE, Rutherford TJ, Pecorelli S, Santin AD. Downregulation of membrane complement inhibitors CD55 and CD59 by siRNA sensitises uterine serous carcinoma overexpressing Her2/neu to complement and antibody-dependent cell cytotoxicity in vitro: implications for trastuzumab-based immunotherapy.
Br J Cancer 2012;
106:1543-50. [PMID:
22531721 PMCID:
PMC3341945 DOI:
10.1038/bjc.2012.132]
[Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background:
We evaluated the expression of CD46, CD55 and CD59 membrane-bound complement-regulatory
proteins (mCRPs) in primary uterine serous carcinoma (USC) and the ability of small
interfering RNA (siRNA) against these mCRPs to sensitise USC to complement-dependent
cytotoxicity (CDC) and antibody (trastuzumab)-dependent cellular cytotoxicity (ADCC)
in vitro.
Methods:
Membrane-bound complement-regulatory proteins expression was evaluated using real-time
PCR (RT–PCR) and flow cytometry, whereas Her2/neu expression and
c-erbB2 gene amplification were assessed using immunohistochemistry, flow
cytometry and fluorescent in-situ hybridisation. The biological effect of
siRNA-mediated knockdown of mCRPs on HER2/neu-overexpressing USC cell lines was
evaluated in CDC and ADCC 4-h chromium-release assays.
Results:
High expression of mCRPs was found in USC cell lines when compared with normal
endometrial cells (P<0.05). RT–PCR and FACS analyses demonstrated that
anti-mCRP siRNAs were effective in reducing CD46, CD55 and CD59 expression on USC
(P<0.05). Baseline complement-dependent cytotoxicity (CDC) against USC
cell lines was low (mean±s.e.m.=6.8±0.9%) but significantly
increased upon CD55 and CD59 knockdown (11.6±0.8% and
10.7±0.9%, respectively, P<0.05). Importantly, in the absence
of complement, both CD55 and CD59, but not CD46, knockdowns significantly augmented ADCC
against USC overexpressing Her2/neu.
Conclusion:
Uterine serous carcinoma express high levels of the mCRPs CD46, CD55 and CD59. Small
interfering RNA inhibition of CD55 and CD59, but not CD46, sensitises USC to both CDC
and ADCC in vitro, and if specifically targeted to tumour cells, may
significantly increase trastuzumab-mediated therapeutic effect in vivo.
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