Disruption of the anaphase-promoting complex confers resistance to TTK inhibitors in triple-negative breast cancer

Abstract

TTK protein kinase (TTK), also known as Monopolar spindle 1 (MPS1), is a key regulator of the spindle assembly checkpoint (SAC), which functions to maintain genomic integrity. TTK has emerged as a promising therapeutic target in human cancers, including triple-negative breast cancer (TNBC). Several TTK inhibitors (TTKis) are being evaluated in clinical trials, and an understanding of the mechanisms mediating TTKi sensitivity and resistance could inform the successful development of this class of agents. We evaluated the cellular effects of the potent clinical TTKi CFI-402257 in TNBC models. CFI-402257 induced apoptosis and potentiated aneuploidy in TNBC lines by accelerating progression through mitosis and inducing mitotic segregation errors. We used genome-wide CRISPR/Cas9 screens in multiple TNBC cell lines to identify mechanisms of resistance to CFI-402257. Our functional genomic screens identified members of the anaphase-promoting complex/cyclosome (APC/C) complex, which promotes mitotic progression following inactivation of the SAC. Several screen candidates were validated to confer resistance to CFI-402257 and other TTKis using CRISPR/Cas9 and siRNA methods. These findings extend the observation that impairment of the APC/C enables cells to tolerate genomic instability caused by SAC inactivation, and support the notion that a measure of APC/C function could predict the response to TTK inhibition. Indeed, an APC/C gene expression signature is significantly associated with CFI-402257 response in breast and lung adenocarcinoma cell line panels. This expression signature, along with somatic alterations in genes involved in mitotic progression, represent potential biomarkers that could be evaluated in ongoing clinical trials of CFI-402257 or other TTKis.

Targeting the cell cycle in breast cancer: towards the next phase

“…Based on the APC/C-mediated biology of resistance to TTK inhibition, we investigated whether clinical tumours harbour alterations to APC/C complex components, which could be indicative of APC/C functional capacity and therefore predictive of TTK inhibitor response. These analyses revealed recurrent genetic disruption and gene expression changes in APC/C components in various tumour types [73]. Furthermore, we identified a two-gene metagene (ANAPC4 and CDC20 mRNA expression signature) that was strongly correlated with in vitro response to CFI-402257 in breast and lung cancer cell line panels that we tested.…”

“…Similar to other clinical kinase inhibitors, gatekeeper mutations in the active site of TTK have been described to confer resistance to TTK inhibitors in vitro [72], although the clinical relevance of such mutations must be evaluated prospectively in patients who develop resistance (Figure 2(d)). In a preclinical setting, we recently described delay of mitotic exit as a mechanism of TNBC resistance to the clinical TTK inhibitor, CFI-402257 using CRISPR/Cas9 functional genomic screens [73] ( Figure 2(d)). Our findings independently validated those of Sansregret et al who identified the same mechanism of resistance using siRNA screens with the tool compound reversine, another TTK inhibitor [74,75].…”

Upregulation of Thr/Tyr kinase Increases the Cancer Progression by Neurotensin and Dihydropyrimidinase-Like 3 in Lung Cancer

“…Reduced in TTK level or activity in tumors can lead to a decrease of cell viability and division; thus, inhibition of TTK has been regard as an attractive target for anti-cancer drug development [6][7][8]. TTK has been also reported that upregulation of TTK increases lung cancer progression due to X-linked deubiquitinase USP9X dysfunction [9,10]. With several therapeutic agents targeting TTK currently being evaluated as chemotherapy agents in clinical trials, better understanding of the molecular mechanisms mediating TTK-mediated oncogenic cascade could have a noteworthy impact by directorial their successful clinical application and preventing chemo-resistance development.…”

Recent Advances in the Development of Indazole‐based Anticancer Agents

“…Tyrosine threonine kinase (TTK), also known as monopolar spindle 1 (Mps1) or phosphotyrosine‐picked threonine kinase (PYT), is a key regulator of the spindle assembly checkpoint whose function is to maintain genomic integrity . TTK is overexpressed in a variety of solid cancers, and its expression level correlates with high histological grades in tumors .…”

“…Tyrosine threonine kinase (TTK), also knowna sm onopolar spindle 1( Mps1) or phosphotyrosine-picked threonine kinase (PYT), is ak ey regulator of the spindle assembly checkpoint whose function is to maintain genomic integrity. [63] TTK is overexpressed in av ariety of solid cancers,a nd its expression level correlates with high histological gradesi nt umors. [64][65][66] In contrast, reduction of the level of TTK by RNAii na neuploid cells could decrease the survival rate of cancerc ells andi nduce their apoptosis, [65] suggesting that TTK is ap romising target in the development of anticancer therapeutics.…”