Chemical modifications are an effective way to improve the therapeutic properties of small interfering RNAs (siRNAs), making them more resistant to degradation in serum and ensuring their delivery to target cells and tissues. Here, we studied the carrier-free biodistribution and biological activity of a nuclease-resistant anti-MDR1 cholesterol-siRNA conjugate in healthy and tumor-bearing severe combined immune deficiency (SCID) mice. The attachment of cholesterol to siRNA provided its efficient accumulation in the liver and in tumors, and reduced its retention in the kidneys after intravenous and intraperitoneal injection. The major part of cholesterol-siRNA after intramuscular and subcutaneous injections remained in the injection place. Confocal microscopy data demonstrated that cholesterol-siRNA spread deep in the tissue and was present in the cytoplasm of almost all the liver and tumor cells. The reduction of P-glycoprotein level in human KB-8-5 xenograft overexpressing the MDR1 gene by 60% was observed at days 5-6 after injection. Then, its initial level recovered by the eighth day. The data showed that, regardless of the mode of administration (intravenous, intraperitoneal, or peritumoral), cholesterol-siMDR efficiently reduced the P-glycoprotein level in tumors. The designed anti-MDR1 conjugate has potential as an adjuvant therapeutic for the reversal of multiple drug resistance of cancer cells.

The forkhead boxO transcription factor (FOXO) is a component of the insulin signalling pathway and plays a role in responding to adverse conditions, such as oxidative stress and starvation. In stressful conditions, FOXO moves from the cytosol to the nucleus where it activates gene expression programmes. Here, we show that FOXO in Drosophila melanogaster responds to heat stress as it does to other stressors. The catecholamine signalling pathway is another component of the stress response. In Drosophila, dopamine and octopamine levels rise steeply under heat, nutrition and mechanical stresses, which are followed by a decrease in the activity of synthesis enzymes. We demonstrate that the nearly twofold decline of FOXO expression in foxoBG01018 mutants results in dramatic changes in the metabolism of dopamine and octopamine and the overall response to stress. The absence of FOXO increases tyrosine decarboxylase activity, the first enzyme in octopamine synthesis, and decreases the enzymatic activity of enzymes in dopamine synthesis, alkaline phosphatase and tyrosine hydroxylase, in young Drosophila females. We identified the juvenile hormone as a mediator of FOXO regulation of catecholamine metabolism. Our findings suggest that FOXO is a possible trigger for endocrinological stress reactions.

After decades of nonspecific lymphoma therapy, personalized approaches such as described here are on the horizon.

In this study, we examined the in vivo toxicity of the liposomes F consisting of 1,26-bis(cholest-5-en-3-yloxycarbonylamino)-7,11,16,20-tetraazahexacosan tetrahydrochloride, lipid-helper 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine and folate lipoconjugate (O-{2-[rac-2,3-di(tetradecyloxy)prop-1-yloxycarbonyl]aminoethyl}-O’-[2-(pteroyl-L-glutam-5-yl)aminoethyl]octadecaethyleneglycol) and investigated the antitumor effect of combined antitumor therapy consisting of MDR1-targeted siMDR/F complexes and conventional polychemotherapy using tumor xenograft initiated in immunodeficient mice. Detailed analysis of acute and chronic toxicity of this liposomal formulation in healthy C57BL/6J mice demonstrated that formulation F and parent formulation L (without folate lipoconjugate) have no acute and chronic toxicity in mice. The study of the biodistribution of siMDR/F lipoplexes in SCID mice with xenograft tumors formed by tumor cells differing in the expression level of folate receptors showed that the accumulation in various types of tumors strongly depends on the abandons of folate receptors in tumor cells and effective accumulation occurs only in tumors formed by cells with the highest FR levels. Investigating the effects of combined therapy including anti-MDR1 siRNA/F complexes and polychemotherapy on a multidrug-resistant KB-8-5 tumor xenograft in SCID mice demonstrated that siMDR/F increases the efficiency of polychemotherapy: the treatment leads to pronounced inhibition of tumor growth, reduced necrosis and inflammation, and stimulates apoptosis in KB-8-5 tumor tissue. At the same time, it does not induce liver toxicity in tumor-bearing mice. These data confirm that folate-containing liposome F mediated the extremely efficient delivery of siRNA in FR-expressing tumors in vivo and ensured the safety and effectiveness of its action.