Page 39 - SDIR5 Abstract book 21 12 2021.

IMAGING IN CANCER

The Role of Nek2 on Centrosome Clustering in Cancer Cells with Extra Centrosomes

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Batuhan Mert Kalkan , Selahattin Can Özcan , Ata Alpay Canbaz , Ceyda Açılan Ayhan
1 Koç University, Graduate School of Health Sciences, Istanbul, Turkey
2 Koc University, Translational Medicine Research Center (KUTTAM), Istanbul, Turkey
3 Koc University, School of Medicine, Istanbul, Turkey

Background: Unlike normal cells, cancer cells frequently exhibit extra centrosomes, which tend to form
multipolar spindles (MPS), triggering cell death. Nevertheless, cancer cells divide successfully by clustering
their extra centrosomes into two poles. Nek2 kinase is a key molecule regulating mitotic processes,
including centrosome cycle. In this project, we tested whether Nek2 has a role in centrosome clustering in
addition to its role in splitting centrioles, and which of the Nek2 targets might be responsible. This way, we
wish to find novel strategies that may selectively kill cancer cells exhibiting supernumerary centrosomes.
Materials-Methods: Unclustering effect of Nek2 was studied in cells with endogenously supernumerary
centrosomes (N1E115), or via induction of extra centrosomes via microtubule inhibitors and PLK4
overexpression (U2OS, MDA-MB-231). Nek2 was overexpressed under a Dox inducible promoter or
silenced using siRNA or knockout using gRNAs. Centrosomes were labelled using ɤ-Tubulin. Known Nek2
targets with relevant function were assessed for their involvement in centrosomal unclustering (C-NAP1,
Rootletin, Gas2L1, Trf1) using KO or siRNA. Live cell imaging was utilized to determine the duration of
metaphase. Results: Overexpression of Nek2 induced unclustering of extra centrosomes and lead to MPS,
while reduction of Nek2 reclustered the poles, leading bipolar divisions in the cell lines studied. Known
Nek2 targets tested have shown that they don't involve in the centrosome clustering mechanism which
Nek2 regulates. Nek2 organizes centrosome clustering independent of a known pathway orchestrated by
Kifc1 (HSET). Moreover, overexpression of Nek2 abridges the duration of metaphase, which could interfere
centrosome clustering events requiring time during metaphase. We are currently studying to elucidate the
mechanism of Nek2 regulating centrosome clustering in cancer cells. Conclusion: In our studies, we
assigned a novel function for Nek2 in centrosome clustering. Understanding the mechanism will provide
new translational approaches for cancer-specific treatment.
Keywords: Nek2, centrosome clustering, cancer

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