Targeting the Chromosomal Passenger Complex Subunit INCENP Induces Polyploidization, Apoptosis, and Senescence in Neuroblastoma

Abstract

Chromosomal passenger complex (CPC) has been demonstrated to be a potential target of cancer therapy by inhibiting Aurora B or survivin in different types of cancer including neuroblastoma. However, chemical inhibition of either Aurora B or survivin does not target CPC specifically due to off-target effects or CPC-independent activities of these two components. In a previous chromatin-focused siRNA screen, we found that neuroblastoma cells were particularly vulnerable to loss of INCENP, a gene encoding a key scaffolding component of the CPC. In this study, INCENP was highly expressed by neuroblastoma cells, and its expression decreased following retinoic acidinduced neuroblastoma differentiation. Elevated levels of INCENP were significantly associated with poor prognosis in primary tumors of neuroblastoma patients with high-risk disease. Genetic silencing of INCENP reduced the growth of both MYCN-wild-type and MYCN-amplified neuroblasto-ma cell lines in vitro and decreased the growth of neuroblastoma xenografts in vivo, with significant increases in murine survival. Mechanistically, INCENP depletion suppressed neuroblastoma cell growth by inducing polyploidization, apoptosis, and senescence. In most neuroblastoma cell lines tested in vitro, apoptosis was the primary cell fate after INCENP silencing due to induction of DNA damage response and activation of the p53-p21 axis. These results confirm that CPC is a therapeutic target in neuroblastoma, and targeting INCENP is a novel way to disrupt the activity of CPC and inhibit tumor progression in neuroblastoma.Significance: Dysregulation of INCENP contributes to neuroblastoma tumorigenesis and targeting INCENP presents a novel strategy to disrupt the activity of chromosomal passenger complex and inhibit neuroblastoma progression. INCENP encodes the inner centromere protein (INCENP), which is the structural and regulatory component of the chromosomal passenger complex (CPC) comprised of INCENP, survivin, Borealin, and the Aurora B kinase (9). CPC is responsible for proper chromosomal alignment, segregation, and cytokinesis during the mitosis (9). In the CPC, INCENP plays two critical roles: firstly, it functions as a scaffold protein coordinating assembly of this complex by interacting with all the other three components, and secondarily, the interaction between INCENP and Aurora B is necessary for activation of the Aurora B kinase, the catalytic subunit of this complex (9). Thus, disruption of INCENP expression leads to dissociation of the whole complex and limits Aurora B kinase activity (10, 11). Targeting the CPC has been led by strategies aimed at targeting survivin or Aurora B kinase in neuroblastoma because inhibition of either of them significantly blocks neuroblastoma tumor cell growth in vitro and xenograft growth in vivo (12-15). Recent genome-wide meta-analyses

Localization matters: nuclear-trapped Survivin sensitizes glioblastoma cells to temozolomide by elevating cellular senescence and impairing homologous recombination

“…This further reinforces transcriptional repression of RAD51 and thereby leads to highly reduced HR activity, which results in persistent DSBs and the generation of chromosome aberrations, senescence progression and its maintenance. Of note, also silencing of INCENP induced polyploidization, apoptosis, and senescence in neuroblastoma cells, highlighting the importance of proper CPC localization for the prevention of senescence [46]. Opposite, overexpression of wt-Survivin might enhance proper targeting of the CPC complex and reduce cytokinesis failure and senescence, thereby lowering TMZ-induced RAD51 and HR repression, which we could observe at RNA and, particularly, at protein level, where under overexpression of Survivin, RAD51 was stabilized.…”

Inhibition of Aurora Kinase B activity disrupts development and differentiation of salivary glands

“…The DNA damage response triggered after aurora kinase inhibition may direct the cells to repair the break, undergo apoptosis, or become senescent 25 . Immunostaining for the apoptotic marker cleaved caspase-3 showed abundant epithelial expression following Barasertib treatment compared with controls (Fig.…”

“…Previous studies have shown that these irregular nuclei arise with AURKB inhibitors because cells enter M phase and condense their chromosomes, yet they eventually decondense without proper segregation and form mostly single and irregular-shaped nuclei 20 . These chromatin aberrations are reported to increase the DNA damage response 25 and lead to cell death or cell cycle arrest in highly proliferating cells 39 . Our data demonstrate the formation of p.H2AX foci in the treated explants, suggesting that loss of AURKB rapidly predisposed the highly proliferating bud cells to double-strand DNA breaks (DSB).…”

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“…Another study showed that CDCA5, which is transcribed by E2F1, promotes oncogenesis by enhancing cell proliferation and inhibiting apoptosis via the AKT pathway in HCC [ 30 ]. In addition, INCENP dysregulation has also been confirmed to be related to the occurrence and development of a variety of tumors [ 31-34 ]. INCENP depletion can suppress neuroblastoma cell growth by inducing polyploidization, apoptosis, and senescence [ 31 ].…”