Background: Neuroblastoma is the most common extracranial pediatric solid tumor with poor prognosis for high-risk disease. Proviral Integration site for Murine leukemia virus (PIM) kinases, a family of serine/threonine kinases, are overexpressed in some cancers and high PIM1 expression is associated with lower survival in neuroblastoma. Enhanced lipid metabolism regulates pro-tumorigenic cellular processes and PIM kinases promote lipid storage, but little is known about their effect on other aspects of lipid metabolism. We aimed to evaluate the effect of PIM kinases on lipid uptake. 

Methods: The QBT fatty acid uptake assay (Molecular Devices) was utilized. SK-N-AS and BE(2)-C human neuroblastoma cells were treated for 48 hours with varying concentrations of PIM inhibitors, AZD1208 or SGI-1776. After 4 hours of fatty acid deprivation, BODIPY dodecanoic acid fluorescent fatty acid analog and quenching dye were added. Kinetic reading of the fluorescence (excitation 485nm, emission 515nm) was measured every 1.3 minutes for 1 hour. Fluorescence was reported as mean RFU ± SEM and a two-tailed t-test was performed.

Results: PIM inhibition with AZD1208 and SGI-1776 decreased fatty acid uptake in SK-N-AS cells with 7432.3±570.5 RFU for untreated cells versus 4942.0±456.7 RFU for AZD1208 40mM (p=0.004) and 5882.4±273.7 RFU for SGI-1776 2mM (p=0.03) after 40 minutes of incubation. Similar findings were seen in BE(2)-C cells with 4704.9±472.0 RFU for untreated cells versus 3172.8±257.8 RFU for AZD1208 40mM (p=0.02) and 3358.5±298.5 RFU for SGI-1776 5mM (p=0.04).

Conclusion: These results indicate that PIM kinases promote fatty acid uptake in neuroblastoma. Future studies will focus on using siRNA to determine which PIM kinase yields this effect. We will also evaluate the mechanism by measuring changes in expression of fatty acid transporters. PIM inhibition may be useful as a novel therapeutic strategy for neuroblastoma.