CEP131 Abrogates CHK1 Inhibitor-Induced Replication Defects and Is Associated with Unfavorable Outcome in Neuroblastoma

Abstract

Checkpoint kinase 1 (CHK1) plays a key role in genome surveillance and integrity throughout the cell cycle. Selective inhibitors of CHK1 (CHK1i) are undergoing clinical evaluation for various human malignancies, including neuroblastoma. Recently, we reported that CHK1i, PF-477736, induced a p53-mediated DNA damage response. As a result, the cancer cells were able to repair DNA damage and became less sensitive to CHK1i. In this study, we discovered that PF-477736 increased expression of MDM2 oncogene along with CHK1i-induced replication defects in neuroblastoma NB-39-nu cells. A mass spectrometry analysis of protein binding to MDM2 in the presence of CHK1i identified the centrosome-associated family protein 131 (CEP131), which was correlated with unfavorable prognosis of neuroblastoma patients. We revealed that MDM2 was associated with CEP131 protein degradation, whereas overexpression of CEP131 accelerated neuroblastoma cell growth and exhibited resistance to CHK1i-induced replication defects. Thus, these findings may provide a future therapeutic strategy against centrosome-associated oncogenes involving CEP131 as a target in neuroblastoma.

Clinical Response to a PARP Inhibitor and Chemotherapy in a Child with BARD1-Mutated Refractory Neuroblastoma: A Case Report

“…We demonstrate for the first time that bi-allelic loss of BARD1 confers a targetable vulnerability in this disease. In our cohort of 59 NBLs, we found 3 cases with P/LP germline mutations in HRR genes ( Figure 1 D ), consistent with recent genomic profiling of HR-NBL germline and tumor samples, which showed multiple defective DNA repair mechanisms ( ATRX , 11q LOH, ATM , H2AFX , CHK1 , CEP131 and MRE11 ) 41 – 45 . Published studies of drug exposure experiments using in vitro cell line models and in vivo zebrafish models also suggest that patients with such defects may benefit from a similar therapeutic strategy 46 – 56 .…”

FGFR2 loss sensitizes MYCN‐amplified neuroblastoma CHP134 cells to CHK1 inhibitor–induced apoptosis

“…Generation of a stable cell line transduced with a lentiviral-mediated expression system was performed using the ViraPower Lentiviral Gateway Expression Kit (Invitrogen), as described previously. 26…”

Mdm2-Mediated Downmodulation of GRK2 Restricts Centrosome Separation for Proper Chromosome Congression

“…Our group and others have identified Mdm2 as the main E3 ligase implicated in GRK2 turnover upon GPCR stimulation [ 33 , 34 , 35 ], although the E3 ligase targeting GRK2 during the G2 remains to be identified [ 31 ]. Interestingly, downregulation of the centrosome-associated protein CEP131 by Mdm2 has been associated with centrosome amplification [ 36 , 37 ]; however, no effects in centrosome separation have been described so far. Our results show that control of GRK2 stability by Mdm2 is an intrinsic event in the regulation of centrosome separation that counterbalances EGF-induced and GRK2-mediated activation of the MST2–Nek2A module.…”