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Identification of novel candidate biomarkers of epithelial ovarian cancer by profiling the Secretomes of three-dimensional genetic models of ovarian carcinogenesis.Lawrenson, Kate; Mhawech-Fauceglia, Paulette; Worthington, Jenny; Spindler, Tassja J.; O'Brien, Darragh; Lee, Janet M.; Spain, Georgia; Sharifian, Maryam; Wang, Guisong; Darcy, Kathleen M.; et al. (Wiley, 2014-09-09)Epithelial ovarian cancer is still considered the most lethal gynecological malignancy and improved early detection of ovarian cancer is crucial to improving patient prognoses. To address this need, we tested whether candidate EOC biomarkers can be identified using three-dimensional in vitro models. We quantified changes in the abundance of secreted proteins in a 3D genetic model of early-stage EOC, generated by expressing CMYC and KRAS(G12V) in TERT-immortalized normal ovarian epithelial cells. Cellular proteins were labeled in live cells using stable isotopic amino acid analogues, and secreted proteins identified and quantified using liquid chromatography-tandem mass spectrometry. 37 and 55 proteins were differentially expressed by CMYC and CMYC+KRAS(G12V) expressing cells respectively (P<0.05; >2-fold). We evaluated expression of the top candidate biomarkers in ˜210 primary EOCs: CHI3L1 and FKBP4 are both expressed by >96% of primary EOCs, and FASN and API5 are expressed by 86% and 75% of cases. High expression of CHI3L1 and FKBP4 was associated with worse patient survival (P=0.042 and P=0.002 respectively). Expression of LGALS3BP was positively associated with recurrence (P=0.0001) and suboptimal debulking (P=0.018) suggesting that these proteins may be novel prognostic biomarkers. Furthermore, within early stage tumours (I/II), high expression of API5, CHI3L1 and FASN was associated with high tumour grade (P=3x10(-4) , P=0.016, P=0.010, respectively). We show in vitro cell biology models of early-stage cancer development can be used to identify novel candidate biomarkers for disease, and report the identification of proteins that represent novel potential candidate diagnostic and prognostic biomarkers for this highly lethal disease. © 2014 Wiley Periodicals, Inc.
Microcell-mediated chromosome transfer identifies EPB41L3 as a functional suppressor of epithelial ovarian cancers.Dafou, Dimitra; Grun, Barbara; Sinclair, Jonathan; Lawrenson, Kate; Benjamin, Elizabeth C.; Hogdall, Estrid; Kruger-Kjaer, Susanne; Christensen, Lise; Sowter, Heidi M.; Al-Attar, Ahmed; et al. (2010-07)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 EPB41L3 (erythrocyte membrane protein band 4.1-like 3, alternative names DAL-1 and 4.1B) was a candidate ovarian cancer-suppressor gene. Immunoblot analysis showed that EPB41L3 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.