Long-circulating and fusogenic liposomes loaded with a glucoevatromonoside derivative induce potent antitumor response.

Cancer is an important public health problem, being one of the leading causes of death worldwide. Most antineoplastic agents cause severe toxic effects and some types of cancer do not respond or are resistant to the existing pharmacotherapy, necessitating the research and development of new therapeutic strategies. Cardenolides have shown significant antitumor activity due to their ability to inhibit the Na+K+ATPase enzyme, and the expression of this enzyme is increased in tumor cells. Glucoevatromonoside containing peracetylated glucose hydroxyl groups (GEVPG) is a cardenolide derivative that has low solubility in aqueous media, which constitutes a barrier to its potential biological applications. In this context, the use of liposomes represents a promising strategy to deliver GEVPG, thus allowing its intravenous administration. In this study, long-circulating and fusogenic liposomes containing GEVPG (SpHL-GEVPG) were developed, and their chemical and physicochemical properties were evaluated. SpHL-GEVPG presented adequate properties, including a mean diameter of 182.2 ± 2.7 nm, a polydispersity index equal to 0.36 ± 0.03, a zeta potential of -2.37 ± 0.31 mV, and a GEVPG entrapment of 0.38 ± 0.04 mg/mL. Moreover, this formulation showed a good stability after having been stored for 30 days at 4 °C. The cytotoxic studies against breast (MDA-MB-231, MCF-7, and SKBR-3) and lung (A549) cancer cell lines demonstrated that SpHL-GEVPG treatment significantly reduced the cell viability. In addition, the SpHL-GEVPG formulation presented a good selectivity toward these cancer cells. The evaluation of the therapeutic efficacy of the treatment with SpHL-GEVPG showed a potent anticancer effect in an A549 human lung cancer xenograft model. SpHL-GEVPG administered at doses of 1.0 and 2.0 mg/kg (i.v.) induced antitumor effect comparable to paclitaxel given at dose of 10 mg/kg (i.v.) to mice. Therefore, the results of the present work indicate the potential applicability of SpHL-GEVPG as a new anticancer formulation.

Progesterone 5ß-reductase genes of the Brassicaceae family as function-associated molecular markers.

This study aimed to define progesterone 5ß-reductases (P5ßR, EC 1.3.99.6, enone 1,4-reductases) as function-associated molecular markers at the plant family level. Therefore cDNAs were isolated from 25 Brassicaceae species, including two species, Erysimum crepidifolium and Draba aizoides, known to produce cardiac glycosides. The sequences were used in a molecular phylogeny study. The cladogram created is congruent to the existing molecular analyses. Recombinant His-tagged forms of the P5ßR cDNAs from Aethionema grandiflorum, Draba aizoides, Nasturtium officinale, Raphanus sativus and Sisymbrium officinale were expressed in E. coli. Enone 1,4-reductase activity was demonstrated in vitro using progesterone and 2-cyclohexen-1-one as substrates. Evidence is provided that functional P5ßRs are ubiquitous in the Brassicaceae. The recombinant P5ßR enzymes showed different substrate preferences towards progesterone and 2-cyclohexen-1-one. Sequence comparison of the catalytic pocket of the P5ßR enzymes and homology modelling using Digitalis lanata P5ßR (PDB ID: 2V6G) as template highlighted the importance of the hydrophobicity of the binding pocket for substrate discrimination. It is concluded that P5ßR genes or P5ßR proteins can be used as valuable function-associated molecular markers to infer taxonomic relationship and evolutionary diversification from a metabolic/catalytic perspective.