Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The . gov means it’s official. Federal government websites often end in VSports app下载. gov or . mil. Before sharing sensitive information, make sure you’re on a federal government site. .

Https

The site is secure V体育官网. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely. .

. 2018 Oct;20(10):965-974.
doi: 10.1016/j.neo.2018.08.002. Epub 2018 Aug 25.

Dual BRD4 and AURKA Inhibition Is Synergistic against MYCN-Amplified and Nonamplified Neuroblastoma

Joshua Felgenhauer  1 , Laura Tomino  1 , Julia Selich-Anderson  1 , Emily Bopp  2 , Nilay Shah  3
Affiliations

Dual BRD4 and AURKA Inhibition Is Synergistic against MYCN-Amplified and Nonamplified Neuroblastoma

Joshua Felgenhauer et al. Neoplasia. 2018 Oct.

Abstract

A majority of cases of high-risk neuroblastoma, an embryonal childhood cancer, are driven by MYC or MYCN-driven oncogenic signaling. While considered to be directly "undruggable" therapeutically, MYC and MYCN can be repressed transcriptionally by inhibition of Bromodomain-containing protein 4 (BRD4) or destabilized posttranslationally by inhibition of Aurora Kinase A (AURKA). Preclinical and early-phase clinical studies of BRD4 and AURKA inhibitors, however, show limited efficacy against neuroblastoma when used alone. We report our studies on the concomitant use of the BRD4 inhibitor I-BET151 and AURKA inhibitor alisertib. We show that, in vitro, the drugs act synergistically to inhibit viability in four models of high-risk neuroblastoma. We demonstrate that this synergy is driven, in part, by the ability of I-BET151 to mitigate reflexive upregulation of AURKA, MYC, and MYCN in response to AURKA inhibition VSports手机版. We then demonstrate that I-BET151 and alisertib are effective in prolonging survival in four xenograft neuroblastoma models in vivo, and this efficacy is augmented by the addition of the antitubule chemotherapeutic vincristine. These data suggest that epigenetic and posttranslational inhibition of MYC/MYCN-driven pathways may have significant clinical efficacy against neuroblastoma. .

PubMed Disclaimer

Figures

Figure 1
Figure 1
I-BET151 and alisertib are synergistic in their effects on neuroblastoma cell viability in vitro. Combination Index (CI) plots are shown for NB1643 (A), NB-SD (B), SK-N-SH (C), and SK-N-AS (D) neuroblastoma cell lines. Cells were treated with a combination of doses of I-BET151 and alisertib for 48 hours, as described in the methods, and images were obtained to quantify percentage confluence per well. Fraction affected (Fa) is defined as 100 − percent confluence and plotted on the x-axis. Each dose combination and the resultant Fa, as well as the Fa for each drug alone at individual doses, were entered into the Compusyn software. From these data, the CI for each dose combination was calculated, determined if the Fa observed was antagonistic (less than each drug's effect alone, CI >1), additive (equal to the effective of each drug alone, CI = 1), or greater-than additive (greater than the effect of each drug alone, CI <1). CI <0.7 is generally considered synergistic. For each cell line, a majority of drug combinations had CI <1, with Fa <0.5 for all such combinations. Representative experiments shown.
Figure 2
Figure 2
AURKA inhibition with alisertib induces increased RNA expression of oncogenes, which is mitigated by BRD4 inhibition with I-BET151. Cells were treated with 1 μM I-BET151, 1 μM alisertib, both drugs, or vehicle control for 24 hours, after which RNA was extracted from each cell line and used for RT-qPCR. Treatment with alisertib alone (dark gray bars) induced overexpression of most oncogenic targets tested in NB-SD (A), NB1643 (B) and SK-N-SH (C) cells, with less of an effect on SK-N-AS (D) cells except for AURKA. Co-treatment of the cells with I-BET151 reduced or entirely abrogated this overexpression for most target genes in all four cell lines. Relative expression shown using ddCt methods, with each gene's expression normalized first to housekeeping genes in each sample then against each gene's expression in the vehicle control. Three independent experiments performed, with mean and standard error plotted; one-way ANOVA based on treatment for NB-SD among the four treatment groups P = 0316, for NB1643 P = .0169, for SK-N-SH P = .0482, and for SK-N-AS P = .0079.
Figure 3
Figure 3
Dual AURKA and BRD4 inhibition is most efficacious in repressing target oncoprotein expression. Western blots of oncoprotein expression in four neuroblastoma cell lines. Cells were treated with 1 μM I-BET151, 1 μM alisertib, both drugs, or vehicle alone for 48 hours, after which cells were lysed and total protein harvested for Western blot. For all four cell lines, treatment with the AURKA inhibitor alisertib caused decreased p-AURKA levels and increased total AURKA expression, but with decreases in MYC and/or MYCN expression. Treatment with BRD4 inhibitor I-BET151 caused decreased in AURKA, MYC, and MYCN expression. Use of both inhibitors caused greater decrease in protein expression of AURKA, MYCN, and MYC as compared to alisertib alone in all three cell lines. Similar changes were seen on CDK4/6 and MCL1 in NB1643 and SK-N-SH cells and in CDK4 and BCL2 in NB-SD cells. SK-N-AS cells showed no effects on CDK6, MCL1, or BCL2 expression with any drug treatments. Immunoblot band intensity was quantified by densitometry and normalized against the actin control for each lane, then against the vehicle control for each cell line. Normalized expression for each band is shown directly below it. Three individual experiments were performed, with representative blots shown.
Figure 4
Figure 4
Drug combinations of I-BET151 and alisertib improve survival of mice with neuroblastoma tumor xenografts. Kaplan-Meier survival curves of tumor xenograft studies. See main text for description of treatment methods; n = 5 mice per treatment group. For mice treated with I-BET151, alisertib, both drugs, or vehicle alone, the two-drug combination was most efficacious as compared to vehicle control in extending survival (see main text for individual comparisons and P values, calculated by Mantel-Cox log-rank test).
Figure 5
Figure 5
Drug combinations of I-BET151 and alisertib with vincristine improve survival of mice with neuroblastoma tumor xenografts. Kaplan-Meier survival curves of tumor xenograft studies. See main text for description of treatment methods; n = 5 mice per treatment group. For mice treated with various combinations of I-BET151, alisertib, vincristine, and vehicle, the three-drug combination was most efficacious as compared to vehicle in extending survival (see main text for individual comparisons and P values, calculated by Mantel-Cox log-rank test).
See this image and copyright information in PMC

References (V体育官网入口)

    1. Ladenstein R. Busulfan and melphalan versus carboplatin, etoposide, and melphalan as high-dose chemotherapy for high-risk neuroblastoma (HR-NBL1/SIOPEN): an international, randomised, multi-arm, open-label, phase 3 trial. Lancet Oncol. 2017;18:500–514. [pmcid,] - PubMed
    1. Erbe AK. Neuroblastoma Patients' KIR and KIR-ligand genotypes influence clinical outcome for dinutuximab-based immunotherapy: a report from the Children's Oncology Group. Clin Cancer Res. 2017 [pmcid,] - PMC - PubMed
    1. London WB. Historical time to disease progression and progression-free survival in patients with recurrent/refractory neuroblastoma treated in the modern era on Children's Oncology Group early-phase trials. Cancer. 2017 [pmcid,] - PMC - PubMed
    1. Brodeur GM, Seeger RC, Schwab M, Varmus HE, Bishop JM. Amplification of N-myc in untreated human neuroblastomas correlates with advanced disease stage. Science. 1984;224:1121–1124. [pmcid,] - PubMed
    1. Wang LL. Neuroblastoma of undifferentiated subtype, prognostic significance of prominent nucleolar formation, and MYC/MYCN protein expression: a report from the Children's Oncology Group. Cancer. 2013;119:3718–3726. [pmcid: PMC4554323] - PMC - PubMed

Publication types (V体育官网入口)

MeSH terms

"V体育ios版" Grants and funding

V体育官网 - LinkOut - more resources