A novel assay to screen siRNA libraries identifies protein kinases as required for chromosome transmission

One of the hallmarks of cancer is chromosome instability (CIN), which leads to aneuploidy, translocations and other chromosome aberrations. However, in the vast majority of human tumors the molecular basis of CIN remains unknown, partially because not all genes controlling chromosome transmission have yet been identified. To address this question, we have developed an experimental high-throughput imaging (HTI) siRNA assay that allows the identification of novel CIN genes. Our method uses a human artificial chromosome (HAC) expressing the GFP transgene. When this assay was applied to screen a siRNA library of protein kinases we identified PINK1, TRIO, IRAK1, PNCK, and TAOK1 as potential novel genes whose knockdown induces various mitotic abnormalities and results in chromosome loss. The HAC-based assay can be applied for screening different siRNA libraries (cell cycle regulation, DNA damage response, epigenetics, transcription factors) to identify additional genes involved in CIN. Identification of the complete spectrum of CIN genes will reveal new insights into mechanisms of chromosome segregation and may expedite the development of novel therapeutic strategies to target the CIN phenotype in cancer cells.