Bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex a new apoptotic agent through Flk-1 down regulation, caspase-3 activation and oligonucleosomes DNA fragmentation

Abstract

New bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex was synthesized and characterized. In vivo anti-angiogenic activities of bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex against Ehrlich ascites carcinoma (EAC) cells are described. The newly synthesized complex resulted in inhibition of proliferation of EAC cells and ascites formation. The anti-tumor effect was found to be through anti-angiogenic activity as evident by the reduction of microvessel density in EAC solid tumors. The anti-angiogenic effect is mediated through down-regulation of VEGF receptor type-2 (Flk-1). The complex was also found to significantly increase the level of caspase-3 in laboratory animals compared to the acridine ligand and to the control group. This was also consistent with the DNA fragmentation detected by capillary electrophoresis that proved the apoptotic effect of the new complex. Our complex exhibited anti-angiogenic and apoptotic activity in vivo, a thing that makes it a potential effective chemotherapeutic agent. The interaction of calf thymus DNA (ct-DNA) with bis(acridine-9-carboxylate)-nitro-europium(III) dihydrate complex has been investigated using fluorescence technique. A competitive experiment of the europium(III)-acridine complex with ethidium bromide (EB) to bind DNA revealed that interaction between the europium(III)-acridine and DNA was via intercalation. The interaction of the synthesized complex with tyrosine kinases was also studied using molecular docking simulation to further substantiate its mode of action.