New Activity of a Protein from Canavalia ensiformis

Abstract

Concanavalin A is a legume lectin which preferentially agglutinates transformed cells and shows antitumor effects on human breast carcinoma cells in vitro and in vivo. It is considered as a new potential antineoplastic agent targeting apoptosis, autophagy, and anti-angiogenesis in preclinical or clinical trials for cancer therapeutics, which has recently become the object of intensive study. In the present investigation, we show the capacity of the lectin to bind manganese, gold, iron, and zinc porphyrins: all potential anticancer agents. The interaction of the legume lectin with the studied compounds has been investigated by tryptophan fluorescence, showing conformational changes within the quaternary and tertiary structures of the protein. The binding of Con A with manganese, gold, and iron porphyrins, as well as adenine, was studied by fluorescence quenching. In contrast, the interaction of Con A with zinc porphyrin caused an increase in Trp fluorescence and a red shift of 10 nm of the emission maximum position.However, the binding of Con A to iron porphyrin was accompanied by a 5 nm blue shift of the emission maximum, and a kD of 0.95 ± 0.13 μM was calculated, respectively. The sigmoidal shape of the curve showed cooperative interactions, which indicated the presence of more than one class of binding site within the Con A molecule for iron porphyrin, confirmed by the Hill slope (h = 1.89±0.46). We have found that the legume lectin interacts with porphyrins and adenine with an affinity (0.14–1.89 µM) similar to that of the non-legume lectin, wheat germ agglutinin. In conclusion, the protein Con A shows new binding activity towards porphyrins with anticancer activities and could find prospective application as a drug delivery molecule that specifically targets cancer cells.

The critical role of quercetin in autophagy and apoptosis in HeLa cells

“…On the other hand, deregulatory autophagy was associated with tumorigenesis, and has been recommended as antitumor therapy. More and more studies have shown that autophagy activity was altered in a variety of human tumor cells [5][6][7]. It should be noted that autophagy may also have antitumor effect in some circumstances, whereas autophagy can also protect tumor cells from destruction under certain conditions.…”

Lectins from Synadenium carinatum (ScLL) and Artocarpus heterophyllus (ArtinM) Are Able to Induce Beneficial Immunomodulatory Effects in a Murine Model for Treatment of Toxoplasma gondii Infection

“…Thus, the original use of lectins in vaccination protocols has been expanded to other applications. Hence, besides its use as therapeutic agents in infectious and parasitic diseases, lectins have been applied as new potential antineoplastic agents targeting apoptosis, autophagy, and anti-angiogenesis in preclinical or clinical trials for cancer therapeutics, and in neurodegenerative disorders, as well (Alegre-Maller et al, 2014; Bogoeva et al, 2014; Aminou et al, 2016; Barbosa-Lorenzi et al, 2016; Dar et al, 2016; Freitas et al, 2016; Ricci-Azevedo et al, 2016). …”

Dual function of lectins — new perspectives in targeted photodynamic therapy

“…Recently, T/Tn specific lectins have been identified as potential targeting molecules [29]. The non-covalent binding of porphyrins to lectins was well studied [30, Bogoeva, 2010 #314], particularly the interaction of wheat germ agglutinin (WGA) [31][32][33][34] and Con A with porphyrins was evaluated and affinity constants in micromolar range were calculated, accordingly [35,36].…”