BioProject

Tetraploidization, or genome doubling, is a prominent event in tumorigenesis, primarily because cell division in polyploid cells is error-prone and produces aneuploid cells. More...

Tetraploidization, or genome doubling, is a prominent event in tumorigenesis, primarily because cell division in polyploid cells is error-prone and produces aneuploid cells. This study investigates changes in gene expression evoked in acute and adapted tetraploid cells and their impact on cell-cycle progression. Acute polyploidy was generated by knockdown of essential regulator of cytokinesis Anillin, which resulted in cytokinesis failure and formation of binucleate cells, or by chemical inhibition of Aurora kinases, causing abnormal mitotic exit with formation of single cells with aberrant nuclear morphology. Transcriptome analysis of these acute tetraploid cells revealed common signatures of activation of the tumor-suppressor protein p53. Suppression of proliferation in these cells was dependent on p53 and its transcriptional target - Cdk inhibitor p21. Rare proliferating tetraploid cells can emerge from acute polyploid populations. Gene expression analysis of single-cell derived, adapted tetraploid clones showed upregulation of several p53 target genes and cyclin D2, the activator of Cdk4/6/2. Overexpression of cyclin D2 in diploid cells strongly potentiated the ability to proliferate with increased DNA content despite the presence of functional p53. These results point out that p53-mediated suppression of proliferation of polyploid cells can be averted by increased levels of oncogenes such as Cyclin D2, elucidating a possible route for tetraploidy-mediated genomic instability in carcinogenesis. Overall design: Three biological replicates of cells derived from isolated 2N and 4N single cells were assessed for differences in gene expression by RNA Seq for a total of 18 samples. Less...