Chromosomal aneuploidy affects the global proteome equilibrium of colorectal cancer cells

Chromosomal aneuploidy has been identified as a prognostic factor in the majority of sporadic carcinomas. However, it is not known how chromosomal aneuploidy affects chromosome-specific protein expression in particular, and the cellular proteome equilibrium in general.

The aim was to detect chromosomal aneuploidy-associated expression changes in cell clones carrying trisomies found in colorectal cancer.

We used microcell-mediated chromosomal transfer to generate three artificial trisomic cell clones of the karyotypically stable, diploid, yet mismatch-deficient, colorectal cancer cell line DLD1--each of them harboring one extra copy of either chromosome 3, 7 or 13. Protein expression differences were assessed by two-dimensional gel electrophoresis and mass spectrometry, compared to whole-genome gene expression data, and evaluated by PANTHER classification system and Ingenuity Pathway Analysis (IPA).

In total, 79 differentially expressed proteins were identified between the trisomic clones and the parental cell line. Up-regulation of PCNA and HMGB1 as well as down-regulation of IDH3A and PSMB3 were revealed as trisomy-associated alterations involved in regulating genome stability.

These results show that trisomies affect the expression of genes and proteins that are not necessarily located on the trisomic chromosome, but reflect a pathway-related alteration of the cellular equilibrium.