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Previous studies have implicated vestigial like 3 (VGLL3), a chromosome 3p12.3 gene that encodes a putative transcription co‐factor, as a candidate tumor suppressor gene (TSG) in high‐grade serous ovarian carcinomas (HGSC), the most common type of epithelial ovarian cancer. A complementation analysis based on microcell‐mediated chromosome transfer (MMCT) using a centric fragment of chromosome 3 (der3p12‐q12.1) into the OV‐90 ovarian cancer cell line haploinsufficient for 3p and lacking VGLL3 expression was performed to assess the effect on tumorigenic potential and growth characteristics. Genetic characterization of the derived MMCT hybrids revealed that only the hybrid that contained an intact VGLL3 locus exhibited alterations of tumorigenic potential in a nude mouse xenograft model and various in vitro growth characteristics. Only stable OV‐90 transfectant clones expressing low levels of VGLL3 were derived. These clones exhibited an altered cytoplasmic morphology characterized by numerous single membrane bound multivesicular‐bodies (MVB) that were not attributed to autophagy. Overexpression of VGLL3 in OV‐90 was achieved using a lentivirus‐based tetracycline inducible gene expression system, which also resulted in MVB formation in the infected cell population. Though there was no significant differences in various in vitro and in vivo growth characteristics in a comparison of VGLL3‐expressing clones with empty vector transfectant controls, loss of VGLL3 expression was observed in tumors derived from mouse xenograft models. VGLL3 gene and protein expression was significantly reduced in HGSC samples (>98%, p

The genetic analysis of nontumorigenic radiation hybrids generated by transfer of chromosome 3 fragments into the tumorigenic OV-90 ovarian cancer cell line identified the 3p12.3-pcen region as a candidate tumor suppressor gene (TSG) locus. In the present study, polymorphic microsatellite repeat analysis of the hybrids further defined the 3p12.3-pcen interval to a 16.1 Mb common region containing 12 known or hypothetical genes: 3ptel-ROBO2-ROBO1-GBE1-CADM2-VGLL3-CHMP2B-POU1F1-HTR1F-CGGBP1-ZNF654-C3orf38-EPHA3-3pcen. Seven of these genes, ROBO1, GBE1, VGLL3, CHMP2B, CGGBP1, ZNF654, and C3orf38, exhibited gene expression in the hybrids, placing them as top TSG candidates for further analysis. The expression of all but one (VGLL3) of these genes was also detected in the parental OV-90 cell line. Mutations were not identified in a comparative sequence analysis of the predicted protein coding regions of these candidates in OV-90 and donor normal chromosome 3 contig. However, the nondeleterious sequence variants identified in the transcribed regions distinguished parent of origin alleles for ROBO1, VGLL3, CHMP2B, and CGGBP1 and cDNA sequencing of the hybrids revealed biallelic expression of these genes. Interestingly, underexpression of VGLL3 and ZNF654 were observed in malignant ovarian tumor samples as compared with primary cultures of normal ovarian surface epithelial cells or benign ovarian tumors, and this occurred regardless of allelic content of 3p12.3-pcen. The results taken together suggest that dysregulation of VGLL3 and/or ZNF654 expression may have affected pathways important in ovarian tumorigenesis which was offset by the transfer of chromosome 3 fragments in OV-90, a cell line hemizygous for 3p.

Although prostate cancer is still the most diagnosed cancer in men, most genes implicated in its progression are yet to be identified. Chromosome abnormalities have been detected in human prostate tumors, many of them associated with prostate cancer progression. Indeed, alterations (including deletions or amplifications) of more than 15 human chromosomes have been reported in prostate cancer. We hypothesized that transferring normal human chromosomes into human prostate cancer cells would interfere with their tumorigenic and/or metastatic properties. We used microcell-mediated chromosome transfer to introduce human chromosomes 10, 12, 17, and 18 into highly tumorigenic (PC-3M-Pro4) and highly metastatic (PC-3M-LN4) PC-3-derived cell lines. We tested the in vitro and in vivo properties of these hybrids. Introducing chromosome 18 into the PC-3M-LN4 prostate cancer cell line greatly reduced its tumorigenic phenotype. We observed retarded growth in soft agar, decreased invasiveness through Matrigel, and delayed tumor growth into nude mice, both subcutaneously and orthotopically. This phenotype is associated with a marker in the 18q21 region. Combined with the loss of human chromosome 18 regions often seen in patients with advanced prostate cancer, our results show that chromosome 18 encodes one or more tumor-suppressor genes whose inactivation contributes to prostate cancer progression. © 2005 Wiley-Liss, Inc.