title: Modelling genetic and clinical heterogeneity in epithelial ovarian cancers.
abstract: The biology underlying early-stage epithelial ovarian cancer (EOC) development is poorly understood. Identifying biomarkers associated with early-stage disease could have a significant impact on reducing mortality. Here, we describe establishment of a three-dimensional (3D) in vitro genetic model of EOC initiation and early-stage neoplastic progression. Normal primary ovarian epithelial (POE) cells, immortalized using hTERT (immortalised ovarian epithelial [IOE] cells), were partially transformed by overexpressing the CMYC oncogene (IOE(CMYC) cells). Subsequent expression of mutant alleles of KRAS (KRAS(G12V)) or BRAF (BRAF(V600E)) created double-mutant lines (IOE(CMYC.KRAS) and IOE(CMYC.BRAF)). The transformed phenotype of IOE(CMYC) cells was further enhanced in concert with KRAS(G12V)/BRAF(V600E) expression, as in vitro analyses indicated that IOE(CMYC) cells had undergone morphological and phenotypic changes characteristic of neoplastic progression. When cultured as 3D spheroids, IOE cells underwent growth arrest, reminiscent of nonproliferative, unstimulated POE in vivo. In contrast, IOSE(CMYC+BRAF/KRAS) cells formed highly proliferative, poly-aggregate spheroid structures, showing increased expression of the Wilms tumour 1 tumourigenic marker and MIB1 proliferation marker. Transcriptomic analyses identified different gene expression profiles between the different cell lines and novel candidate genes (e.g. RGS4, CTGF and THBS1) that are somatically altered in EOCs. Gene expression signatures were compared with signatures from primary EOCs; tumours with IOE(CMYC) 'like' signatures were more likely to be high grade (P = 0.018); tumours with BRAF signatures were associated with improved relapse-free survival (P = 0.003). In conclusion, we have established in vitro 3D models of early-stage EOCs, which reflect genetic and phenotypic heterogeneity of the disease. Molecular genetic characteristics of these models correlated with molecular and clinical features of primary EOCs.
authors.affiliation: UCL EGA Institute for Women's Health, University College London, London, UK.
authors.forename: Kate
authors.initials: K
authors.lastname: Lawrenson
authors.forename: Duncan
authors.initials: D
authors.lastname: Sproul
authors.forename: Barbara
authors.initials: B
authors.lastname: Grun
authors.forename: Maria
authors.initials: M
authors.lastname: Notaridou
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Benjamin
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Jacobs
authors.forename: Dimitra
authors.initials: D
authors.lastname: Dafou
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Sims
authors.forename: Simon A
authors.initials: SA
authors.lastname: Gayther
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D000077216:Carcinoma, Ovarian Epithelial; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008875:Middle Aged; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000401:mortality / Q000473:pathology; D009375:Neoplasms, Glandular and Epithelial / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D061251:Primary Cell Culture; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D048493:Proto-Oncogene Proteins B-raf / Q000502:physiology*; D016271:Proto-Oncogene Proteins c-myc / Q000502:physiology*; D016283:Proto-Oncogene Proteins p21(ras); D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D019098:Telomerase / Q000502:physiology; D018631:ras Proteins / Q000502:physiology*
chemical_list: D014408:Biomarkers, Tumor; C117307:KRAS protein, human; C489427:MYC protein, human; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; C509186:TERT protein, human; D019098:Telomerase; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins