title: A critical role of integrin-linked kinase, ch-TOG and TACC3 in centrosome clustering in cancer cells.
abstract: Many cancer cells contain more than two centrosomes, which imposes a potential for multipolar mitoses, leading to cell death. To circumvent this, cancer cells develop mechanisms to cluster supernumerary centrosomes to form bipolar spindles, enabling successful mitosis. Disruption of centrosome clustering thus provides a selective means of killing supernumerary centrosome-harboring cancer cells. Although the mechanisms of centrosome clustering are poorly understood, recent genetic analyses have identified requirements for both actin and tubulin regulating proteins. In this study, we demonstrate that the integrin-linked kinase (ILK), a protein critically involved in actin and mitotic microtubule organization, is required for centrosome clustering. Inhibition of ILK expression or activity inhibits centrosome clustering in several breast and prostate cancer cell lines that have centrosome amplification. Furthermore, cancer cells with supernumerary centrosomes are significantly more sensitive to ILK inhibition than cells with two centrosomes, demonstrating that inhibiting ILK offers a selective means of targeting cancer cells. Live cell analysis shows ILK perturbation leads cancer cells to undergo multipolar anaphases, mitotic arrest and cell death in mitosis. We also show that ILK performs its centrosome clustering activity in a focal adhesion-independent, but centrosome-dependent, manner through the microtubule regulating proteins TACC3 and ch-TOG. In addition, we identify a specific TACC3 phosphorylation site that is required for centrosome clustering and demonstrate that ILK regulates this phosphorylation in an Aurora-A-dependent manner.
authors.affiliation: Department of Integrative Oncology, British Columbia Cancer Research Centre of the BC Cancer Agency, Vancouver, British Columbia, Canada.
authors.forename: A B
authors.initials: AB
authors.lastname: Fielding
authors.forename: S
authors.initials: S
authors.lastname: Lim
authors.forename: K
authors.initials: K
authors.lastname: Montgomery
authors.forename: I
authors.initials: I
authors.lastname: Dobreva
authors.forename: S
authors.initials: S
authors.lastname: Dedhar
mesh_terms: D064127:Aurora Kinases; D001391:Azo Compounds / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D045744:Cell Line, Tumor; D018385:Centrosome / Q000378:metabolism*; D048749:Cytokinesis / Q000187:drug effects; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology; D034622:RNA Interference; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism; D000099200:Scaffold Protein ILK
chemical_list: D064127:Aurora Kinases; D001391:Azo Compounds; D008869:Microtubule-Associated Proteins; D017346:Protein Serine-Threonine Kinases; D011720:Pyrazoles; D000099200:Scaffold Protein ILK; C454180:CKAP5 protein, human; C552362:QLT 0267; C120551:TACC3 protein, human