Combination of nanosomal form of doxorubicin, interferon alpha, and nitroglycerin in the threatment of 101.8 glioblastoma in Wistar rats

The search for effective approaches to the treatment of patients with glioblastoma is one of the difficult tasks of neurooncology; standard methods of therapy show limited results. Combined therapy, which includes different antitumor mechanisms, can increase its effectiveness. The combination of PLGA nanoform of doxorubicin (Dox-PLGA), antitumor cytokine — interferon alfa (IFN-α), and nitrogen oxide (NO) donor nitroglycerin (NG) was investigated in this work both in vitro (rat C6 glioma) and in vivo (rat 101.8 glioblastoma). MTT assay in the C6 cell line showed great cytotoxicity and antiproliferative effect of the combination of IFN-α with Dox-PLGA and NG. The lowest tumour cell survival was observed when using a high dose of IFN-α (10 ng/ml) in mono-mode. In the in vivo experiment, 32 female Wistar rats with 101.8 glioblastoma received therapy in the following modes: Dox-PLGA + NG; Dox-PLGA + IFN-α; Dox- PLGA + IFN-α + NG. There was a significant increase in median survival and life expectancy (ILE) in all groups receiving therapy compared to the group that did not undergo treatment. The longest median lifespan (27 days), survival up to 100 days (1 animal), ILE (131%) were observed in animals that received the combination Dox-PLGA + IFN-α+ NG, compared to the group without treatment, in which the median lifespan was 15 days. Thus, the therapy of experimental glioblastoma both in vivo and in vitro with the combination of Dox-PLGA + IFN-α + NG has the most pronounced therapeutic and antitumor effect, which must be taken into account when developing new more effective methods of treating human glioblastomas.

Sensitivity of the Natriuretic Peptide/cGMP System to Hyperammonaemia in Rat C6 Glioma Cells and GPNT Brain Endothelial Cells

C-type natriuretic peptide (CNP) is the major natriuretic peptide of the central nervous system and acts via its selective guanylyl cyclase-B (GC-B) receptor to regulate cGMP production in neurons, astrocytes and endothelial cells. CNP is implicated in the regulation of neurogenesis, axonal bifurcation, as well as learning and memory. Several neurological disorders result in toxic concentrations of ammonia (hyperammonaemia), which can adversely affect astrocyte function. However, the relationship between CNP and hyperammonaemia is poorly understood. Here, we examine the molecular and pharmacological control of CNP in rat C6 glioma cells and rat GPNT brain endothelial cells, under conditions of hyperammonaemia. Concentration-dependent inhibition of C6 glioma cell proliferation by hyperammonaemia was unaffected by CNP co-treatment. Furthermore, hyperammonaemia pre-treatment (for 1 h and 24 h) caused a significant inhibition in subsequent CNP-stimulated cGMP accumulation in both C6 and GPNT cells, whereas nitric-oxide-dependent cGMP accumulation was not affected. CNP-stimulated cGMP efflux from C6 glioma cells was significantly reduced under conditions of hyperammonaemia, potentially via a mechanism involving changed in phosphodiesterase expression. Hyperammonaemia-stimulated ROS production was unaffected by CNP but enhanced by a nitric oxide donor in C6 cells. Extracellular vesicle production from C6 cells was enhanced by hyperammonaemia, and these vesicles caused impaired CNP-stimulated cGMP signalling in GPNT cells. Collectively, these data demonstrate functional interaction between CNP signalling and hyperammonaemia in C6 glioma and GPNT cells, but the exact mechanisms remain to be established.