Sphingadienes show therapeutic efficacy in neuroblastoma in vitro and in vivo by targeting the AKT signaling pathway

Abstract

Neuroblastoma is a childhood malignancy that accounts for approximately 15% of childhood cancer deaths. Only 20–35% of children with metastatic neuroblastoma survive with standard therapy. Identification of more effective therapies is essential to improving the outcome of children with high-stage disease. Sphingadienes (SD) are growth-inhibitory sphingolipids found in natural sources including soy. They exhibit chemopreventive activity in mouse models of colon cancer, where they mediate cytotoxicity by inhibiting key pro-carcinogenic signaling pathways. In this study, the effect of SD on neuroblastoma was analyzed. Low micromolar concentrations of SD were cytotoxic to transformed and primary neuroblastoma cells independently of N-Myc amplification status. SD induced both caspase-dependent apoptosis and autophagy in neuroblastoma cells. However, only inhibition of caspase-dependent apoptosis protected neuroblastoma cells from SD-mediated cytotoxicity. SD also inhibited AKT activation in neuroblastoma cells as shown by reduced phosphorylated AKT levels. Pre-treatment with insulin attenuated SD-mediated cytotoxicity in vitro. SD-loaded nanoparticles (NP) administered parenterally to immunodeficient mice carrying neuroblastoma xenografts resulted in cytotoxic levels of SD in the circulation and significantly reduced tumor growth compared to vehicle-treated controls. Analysis of tumor extracts demonstrated reduced AKT activation in tumors of mice treated with SD-NP compared to controls treated with empty NP. Our findings indicate SD are novel potential chemotherapeutic agents that promote neuroblastoma cell death and reduce tumorigenicity in vivo.

YAP promotes the proliferation of neuroblastoma cells through decreasing the nuclear location of p27Kip1 mediated by Akt

“…However, there are in vivo results suggesting that YAP, Akt and p27 kip1 are related to neuroblastoma. 13,22,66 YAP is significantly higher in the malignant neuroblastoma tissues of human, compared to the peritumoral tissues. 13 Inhibition of the Akt signalling pathway shows therapeutic efficacy in neuroblastoma xenografts in vivo.…”

A novel function of sphingosine kinase 2 in the metabolism of sphinga-4,14-diene lipids

“…Our data extends this work by demonstrating that sphingadiene-containing lipids are more slowly catabolized than sphingosine-containing lipids in living cells. Similarly, S1P lyase mutants in the fly Drosophila melanogaster accumulate sphinga-4,6-diene (54), which is speculated to contribute to muscle degeneration (40). In agreement with our data, Jojima et al (39) also found that both SphK1 and SphK2 catalyse sphingadiene phosphorylation as efficiently as sphingosine.…”

“…Naturally occurring sphingadienes inhibit both chemically-and genetically-induced colon cancer development in mice (51)(52)(53), associated with disrupted Akt membrane translocation and signaling (53), and reduced Wnt transcriptional activity (52). Sphingadienes have also been shown to suppress the growth of neuroblastoma xenograft tumors (54).…”

Assembly and Characterization of Biocompatible Coenzyme Q10‐Enriched Lipid Nanoparticles

“…Findings with CoQ 10 reported herein extend the repertoire of hydrophobic bioactive agents to be successfully incorporated into ND (Ryan, 2010). For example, the polyene antibiotic, amphotericin B (Oda et al, 2006), the polyphenol phytonutrient, curcumin (Ghosh et al, 2011), the bioactive sphingolipid, sphingadiene (Zhao et al, 2018), contrast agents for medical diagnostics (Kornmueller et al, 2019), and the cholesterol synthesis inhibitor, simvastatin (Duivenvoorden et al, 2014), have been formulated into ND and characterized in terms of their biological activity. In general, hydrophobic bioactive agent incorporation into ND results in retention, if not enhancement, of biological activity.…”