Abstracts of scientific publications

Centrosomes, which mediate accurate chromosome segregation during mitosis, undergo duplication precisely once per cell division at the G(1)/S boundary. Recently, we described centrosome aberrations as a possible cause of aneuploidy in acute myeloid leukemia (AML) and found a correlation of the percentage of cells carrying abnormal centrosomes to their cytogenetic risk profile. To elucidate the molecular events responsible for the development of centrosome aberrations in AML, tumor RNA of 29 AML samples was hybridized to cDNA microarrays. The microarrays comprised some 2800 different genes with relevance to hematopoiesis, tumorigenesis and mitosis and included a set of 359 centrosome-associated genes. We identified two gene expression signatures, which allowed an accurate classification according to the extent of centrosome aberrations and the ploidy status in 28 of 29 patients each. Specifically, 18 genes were present in both signatures, including genes that code for cell cycle regulatory proteins (cyclin A2, cyclin D3, cyclin H, CDK6, p18(INK4c), p21(Cip1), PAK1) and centrosome-associated proteins (pericentrin, alpha2-tubulin, NUMA1, TUBGCP2, PRKAR2A). In conclusion, the high expression of centrosome-associated genes matches the description of centrosome aberrations in several tumor types. Moreover, in AML the identification of G(1)/S-phase stimulatory genes suggests that one mechanism of aneuploidy induction might be the deregulation of centrosome replication at the G(1)/S boundary.