Microcell-mediated chromosome transfer identifies EPB41L3 as a functional suppressor of epithelial ovarian cancers

Dimitra Dafou, Barbara Grun, John Sinclair, Kate Lawrenson, Elizabeth C Benjamin, Estrid Vilma Solyom Høgdall, Susanne Kruger-Kjaer, Lise Christensen, Heidi M Sowter, Ahmed Al-Attar, Richard Edmondson, Stephen Darby, Andrew Berchuck, Peter W Laird, C Leigh Pearce, Susan J Ramus, Ian J Jacobs, Simon A Gayther

    35 Citationer (Scopus)

    Abstract

    We used a functional complementation approach to identify tumor-suppressor genes and putative therapeutic targets for ovarian cancer. Microcell-mediated transfer of chromosome 18 in the ovarian cancer cell line TOV21G induced in vitro and in vivo neoplastic suppression. Gene expression microarray profiling in TOV21G+18 hybrids identified 14 candidate genes on chromosome 18 that were significantly overexpressed and therefore associated with neoplastic suppression. Further analysis of messenger RNA and protein expression for these genes in additional ovarian cancer cell lines indicated that EPB47 L3 (erythrocyte membrane protein band 4.1-like 3, alternative names DAL-1 and 4.1 B) was a candidate ovarian cancer-suppressor gene. Immunoblot analysis showed that EPB41'L3 was activated in TOV21G+18 hybrids, expressed in normal ovarian epithelial cell lines, but was absent in 15 (78%) of 19 ovarian cancer cell lines. Using immunohistochemistry, 66% of 794 invasive ovarian tumors showed no EPB41L3 expression compared with only 24% of benign ovarian tumors and 0% of normal ovarian epithelial tissues. EPB41L3 was extensively methylated in ovarian cancer cell lines and primary ovarian tumors compared with normal tissues (P = .00004), suggesting this may be the mechanism of gene inactivation in ovarian cancers. Constitutive reexpression of EPB41L3 in a three-dimensional multicellular spheroid model of ovarian cancer caused significant growth suppression and induced apoptosis. Transmission and scanning electron microscopy demonstrated many similarities between EPB41L3-expressing cells and chromosome 18 donor-recipient hybrids, suggesting that EPB41L3 is the gene responsible for neoplastic suppression after chromosome 18 transfer. Finally, an inducible model of EPB41L3 expression in three-dimensional spheroids confirmed that reexpression of EPB41L3 induces extensive apoptotic cell death in ovarian cancers.

    OriginalsprogEngelsk
    TidsskriftNeoPlasia
    Vol/bind12
    Udgave nummer7
    Sider (fra-til)579-89
    Antal sider11
    ISSN1522-8002
    StatusUdgivet - 1 jul. 2010

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