Abstract 4130: TRIM37 expression levels dictate susceptibility to centrosome removal, supporting Plk4 inhibition as a potential new strategy for targeting neuroblastoma
Authors: Meitinger Franz , Davis Robert L. , Kabeche Ruth , Anzola John V. , Wong Yao Liang , Shiau Andrew K. , Desai Arshad , Oegema Karen 
Published: August 2018

Abstract
Centrosomes are the major microtubule-organizing centers in animal cells. Centrosomes catalyze microtubule assembly to accelerate formation of the bipolar mitotic spindle that segregates chromosomes during cell division. To analyze the effect of centrosome removal in normal and cancer cells, we developed centrinone, a potent, specific and cellularly-active inhibitor of the protein kinase polo-like kinase 4 (Plk4), which is essential for centrosome duplication (Wong et al., 2015, Science 348:1155-60). Centrosome-less cells take longer to execute mitosis, and trigger a mitotic stress signaling pathway that results in p53 stabilization and apoptosis and/or senescence of the resulting daughter cells. Failure to form a spindle can also lead to apoptosis during mitosis or exit from mitosis without chromosome segregation (mitotic slippage). In a genome-wide CRISPR/Cas9 loss-of-function screen for resistance to centrinone, we had previously shown that loss of the ubiquitin ligase TRIM37 makes spindle assembly more robust to centrosome removal (Meitinger et al., 2016, J Cell Biol. 214:155-66), raising the possibility that high levels of TRIM37 might increase sensitivity to centrosome removal. Here, we describe the use of single-cell live imaging assays to identify determinants of vulnerability of cancer cells to centrosome removal. Among a panel of 37 tested cell lines, neuroblastoma-derived cell lines were the most sensitive to centrosome removal, exhibiting high levels of apoptosis and rapid loss of viability following treatment with centrinone. We found that sensitivity to centrosome removal correlated with TRIM37 expression levels. Upon centrosome depletion, cells with high TRIM37 levels, particularly neuroblastoma cells, exhibited greatly increased mitotic duration and frequency of mitotic failure. p53 positive neuroblastoma cell lines exhibited apoptosis resulting from mitotic stress-mediated p53 activation and from mitotic failure. Surprisingly, p53 negative neuroblastoma cell lines, which are unable to sense mitotic stress, were also highly sensitive to centrosome removal, with cell death in this case resulting from high rates of mitotic failure. TRIM37 deletion restored the ability of cells to proliferate in centrinone. Thus, centrosome removal via Plk4 inhibition appears to be a promising strategy for therapeutic treatment of neuroblastomas and potentially other cancers with high levels of TRIM37 expression.
Citation Format: Franz Meitinger, Robert L. Davis, Ruth Kabeche, John V. Anzola, Yao Liang Wong, Andrew K. Shiau, Arshad Desai, Karen Oegema. TRIM37 expression levels dictate susceptibility to centrosome removal, supporting Plk4 inhibition as a potential new strategy for targeting neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4130.