American Association for Cancer Research
15357163mct150443-sup-150340_1_supp_3057096_nrgbx6.png (58.37 kB)

Supplemental Fig. S4 from Specific CP110 Phosphorylation Sites Mediate Anaphase Catastrophe after CDK2 Inhibition: Evidence for Cooperation with USP33 Knockdown

Download (58.37 kB)
posted on 2023-04-03, 15:20 authored by Shanhu Hu, Yun Lu, Bernardo Orr, Kristina Godek, Lisa Maria Mustachio, Masanori Kawakami, David Sekula, Duane A. Compton, Sarah Freemantle, Ethan Dmitrovsky

Knock-down of Usp33 in murine lung cancer cells does not affect CP110 protein expression. Effects of Usp33 knock-down at 24,48, 72 and 96 hours on CP110 expression in ED-1 cells.



Chromosomal instability (CIN) is a hallmark of solid tumor biology and is implicated in carcinogenesis. Preferentially eliminating malignant cells by targeting CIN and aneuploidy is an attractive antineoplastic strategy. We previously reported that CDK2 antagonism causes lung cancer cells to undergo anaphase catastrophe and apoptosis through inhibition of phosphorylation of the centrosomal protein CP110. Cells with activating KRAS mutations were particularly sensitive to CDK2 inhibition due to downregulation of CP110 protein levels. This study investigated mechanisms of CDK2 antagonism that mediate anaphase catastrophe via changes in CP110 protein expression and how activated KRAS affects CP110 levels in lung cancers. Site-directed mutagenesis revealed candidate CDK phosphorylation sites of CP110 (residues Ser 170 and Thr 194) critical for conferring anaphase catastrophe by altering centrosome clustering in mitosis. Intriguingly, KRAS mutation can promote CP110 protein degradation by upregulating the ubiquitin ligase SCFcyclinF, which targets CP110 protein for destabilization. Finally, CDK2 inhibitor response was enhanced when combined with knockdown of the deubiquitinase USP33 that in turn accelerates CP110 protein degradation. Thus, this study provides molecular pharmacologic insights into how CP110 expression regulates response to CDK2 inhibition. An improved understanding of in vitro antineoplastic mechanisms of combining CDK2 antagonism with induced CP110 repression provides a rationale for exploring clinical consequences of this strategy. Taken together, preclinical findings obtained from combining CDK2 inhibition with USP33 repression have implications for treating patients with non–small cell lung cancers. Mol Cancer Ther; 14(11); 2576–85. ©2015 AACR.

Usage metrics

    Molecular Cancer Therapeutics



    Ref. manager