1
|
Integrated Cytogenetic and High-Resolution Array CGH Analysis of Genomic Alterations Associated with MYCN Amplification. Cytogenet Genome Res 2011; 134:27-39. [DOI: 10.1159/000324698] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2010] [Indexed: 01/05/2023] Open
|
2
|
Mechanisms of Plk4 haploinsufficiency in hepatocellular carcinogenesis. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.11100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
11100 Background: The pathogenesis of hepatocellular carcinoma (HCC) is multifactorial and includes genetic predisposition, though the precise nature of the latter is as yet poorly understood. Mice heterozygous for the polo like kinase Plk4 develop spontaneous HCC and human HCC cases show a high rate of LOH (loss of heterozygosity) at the Plk4 locus. We hypothesize that Plk4 is a haploinsufficient tumor suppressor in man. The purpose of this study was to investigate the mechanisms by which a 50% reduction of Plk4 leads to carcinogenesis. Methods: We established Plk4± and Plk4+/+ murine embryonic fibroblast cell lines (MEFs) in vitro. 5 of 5 Plk4+/+ MEF lines senesced at passage 7–8 as expected, while 9 of 9 Plk4±MEF lines immortalized in culture under NIH 3T3 protocol. The latter were used at passage 15–20 for in vivo tumorigenesis studies. Results: Plk4± MEFs demonstrated increased ploidy with increased passage number. By passage 4, Plk4± MEFs showed a near tetraploid karyotype as well as multiple chromosomal rearrangements and deletions, as assessed by Spectral Karyotype (SKY) Analysis. 5 out of 9 late passage Plk4± MEF lines injected into NOD-SCID mice grew tumors, with a latency of 3 to 12 weeks. By contrast, injection of Plk4+/+ MEFs yielded no tumors. Tumors generated from injection of Plk4± MEFs were harvested, cultured and submitted to SKY analysis; this showed increased clonal rearrangements and deletions compared to the parent cell lines. Conclusion: A 50% reduction in Plk4 expression results in immortalization, aneuploidy and chromosomal instability in vitro, and tumorigenicity in vivo. These results demonstrate that insufficient levels of Plk4, whether due to mutation or LOH, can contribute to the pathogenesis of HCC. No significant financial relationships to disclose.
Collapse
|