A Novel Therapeutic Mechanism of Imipridones ONC201/ONC206 in MYCN-Amplified Neuroblastoma Cells via Differential Expression of Tumorigenic Proteins

Neuroblastoma is the most common extracranial nervous system tumor in children. It presents with a spectrum of clinical prognostic measures ranging from benign growths that regress spontaneously to highly malignant, treatment evasive tumors affiliated with increased mortality rates. MYCN amplification is commonly seen in high-risk neuroblastoma, rendering it highly malignant and recurrence prone. In our current study, we investigated the therapeutic potential of small molecule inducers of TRAIL, ONC201, and ONC206 in MYCN-amplified IMR-32 and non-MYCN-amplified SK-N-SH human neuroblastoma cell lines. Our results exhibit potent antitumor activity of ONC201 and ONC206 via a novel inhibition of EGF-induced L1CAM and PDGFRβ phosphorylation in both cell lines. Drug treatment significantly reduced cellular proliferation, viability, migration, invasion, tumorsphere formation potential, and increased apoptosis in both cell lines. The protein expression of tumorigenic NMYC, Sox-2, Oct-4, FABP5, and HMGA1 significantly decreased 48 h post-drug treatment, whereas cleaved PARP1/caspase-3 and γH2AX increased 72 h post-drug treatment, compared with vehicle-treated cells in the MYCN-amplified IMR-32 cell line. We are the first to report this novel differential protein expression after ONC201 or ONC206 treatment in human neuroblastoma cells, demonstrating an important multitarget effect which may yield added therapeutic benefits in treating this devastating childhood cancer.

Effect of iloprost on serum creatine kinase and lactate dehydrogenase isoenzymes after isoprenaline-induced cardiac damage in rats

The effect of iloprost was investigated in an experimental model of cardiac damage in rats after isoprenaline (isoproterenol) treatment. Iloprost was administered by continuous subcutaneous infusion at a dose of 0.44 micrograms/kg body weight (b.w.)/min over a total period of 9 days. On day 8, 5 mg isoprenaline/kg b.w. was applied subcutaneously to induce the cardiac damage. The determinations of creatine kinase (CK, EC 2.7.3.2) and CK isoenzymes, lactate dehydrogenase (LDH, EC 1.1.1.27) and LDH isoenzymes as well as a-hydroxybutyrate dehydrogenase (a-HBDH, no EC) were performed 2, 6 and 24 h after isoprenaline application. Immediately after the last blood sampling, the animals were sacrificed and the hearts were examined histologically. Iloprost-pretreated animals showed a reduction in the rise in heart-specific isoenzymes CK-MB and LDH1-3 in the serum after isoprenaline application. A decrease in isoenzymes CK-BB and LDH4-5 in the serum was also observed in iloprost-pretreated rats. However, no difference could be detected histologically in the extent of myocardial necrosis between animals treated with isoprenaline alone or in combination with iloprost. These results suggest a biochemical cardioprotective effect of iloprost in this rat model after isoprenaline application and the lack of correlation with histological findings is discussed.