Plant lectins: potential antineoplastic drugs from bench to clinic

Fungal lectins show differential antiproliferative activity against cancer cell lines

Glycosylation patterns represent an important signature of cancer cells that can be decoded by glycan-binding proteins, i.e., lectins. Fungal lectins have unique properties and diverse structural and glycan-recognition features. In this study, the bioactivities of 22 fungal proteins against nine cancer cell lines were analyzed, and cell phenotypes were assessed with live cell imaging providing mechanistic insights. Eight fungal lectins showed antiproliferative activity, which depended on glycan binding and led to different downstream effects. The β-galactoside-binding chimerolectins Marasmius oreades agglutinin (MOA) and Laetiporus sulphureus lectin (LSL) showed indiscriminate antiproliferative activities with different modes of action, whereas the non-chimeric β-galactoside-binding lectin Agrocybe aegerita galectin (AAG) showed differential antiproliferative activity. Other β-galactoside-binding lectins exerted no effects. Fucose-binding lectins showed differential and strong antiproliferative activities, of which Aleuria aurantia lectin (AAL) exerted the strongest effects. Weaker and differential antiproliferative activities were observed with the Galβ1-3GalNAc-binding actinoporin-like lectins Xerocomus chrysenteron lectin (XCL), Sordaria macrospora transcript associated with perithecial development (TAP1), and Agaricus bisporus lectin (ABL). The different downstream effects of lectins, likely influenced by the targeted glycoligands, show that fungal lectins are valuable tools for identifying new therapeutic targets that can induce cancer cell death or growth arrest via different mechanisms.

Jacalin Attenuates Colitis-Associated Colorectal Carcinogenesis by Inhibiting Tumor Cell Proliferation and Intestinal Inflammation

BACKGROUND

Colorectal cancer (CRC) remains a significant cause of morbidity and mortality worldwide. In patients with inflammatory bowel disease, who have twice the risk of developing CRC, chronic inflammation has been recognized to contribute to colitis-associated cancer (CAC) development. Jacalin, a lectin extracted from jackfruit seeds, has been shown to recognize altered glycosylation and to exert antiproliferative and cytotoxic effects in CRC. However, its activity in CAC remains unknown. Herein, we sought to investigate the effects of jacalin in CAC progression using the dextran sulfate sodium (DSS) and azoxymethane (AOM) mouse model.

METHODS

Colitis-associated cancer induction was performed in male C57BL/6 mice by an intraperitoneal injection of AOM, followed by 3 cycles of 2.5% DSS diluted in drinking water for 7 days, intercalated by 2 weeks of normal drinking water. After 1 week of daily pretreatment, mice were orally treated with phosphate-buffered saline (control group), 100 or 500 µg of jacalin three times a week for an additional 11 weeks.

RESULTS

We showed that jacalin-treated mice presented tumors with reduced volumes and mean size compared to the control group. In addition, both doses of jacalin reduced the number of proliferating cells (Ki-67 positive cells) in tumor tissues, while the higher dose (500 µg) showed also a similar effect in "normal-appearing" colonic crypts. Jacalin treatment attenuated the clinical scores of inflammations, which was accompanied by a reduction of intestinal and/or tumoral production of IL-1β, IL-23, and IL-17.

CONCLUSIONS

Collectively, our findings demonstrated that jacalin suppresses CAC development, highlighting its anti-inflammatory and antitumoral role in the AOM/DSS-induced model.

Component Composition and Features of Biological Activity of Viscum album (Viscaceae)

The review summarizes the data on the chemical composition and some features of biological activity of the European mistletoe Viscum album L. (Viscaceae Batsch). Among secondary metabolites, viscotoxins, lectins, carbohydrates, amino acids, flavonoids, triterpene acids, and nitrogenous compounds predominate in V. album. Mistletoe extracts and their indivdiual components exert various biological activities, including antitumor, immunomodulatory, and antidiabetic activities, and improve cognitive functions.

Wheat Germ Agglutinin (WGA): Its Nature, Biological Role, Significance in Human Nutrition, and Possibility to Be Used as Marker of Whole-Grain Status in Wheat-Based Foods

The growing scientific evidence on the health benefits of whole-grain food consumption has promoted the manufacturing of a great number of products differing in quality and content of whole-grain components. This is particularly true for commercial wheat-based products where it is not always clear how much whole wheat is present considering that in many cases, they are manufactured from reconstituted mill streams and that there is not a standardised globally accepted definition and metrics to objectively evaluate whole-grain status. Attempts have been made to assess the level of "wholegraininess" in wheat products by measuring specific constituents that correlate with different wheat tissues, especially those that are expected to be found in a true whole-grain wheat product. Wheat germ agglutinin (WGA), a small lectin protein present exclusively in the wheat-germ tissues, has been indicated by several scientists as one of these constituents and after founding that its level changes depending on the amount of germ found in a wheat flour, it has been indicated as a biomarker of whole-grain status for wheat products. In this review, the biochemistry of WGA, its methods of detection, and current knowledge on its possibility to be practically utilized as a reliable marker are critically discussed.

Antitumor Activity of a Lectin Purified from Punica granatum Pulps against Ehrlich Ascites Carcinoma (EAC) Cells

BACKGROUND

Lectins are carbohydrate-binding proteins with various pharmacological activities, such as antimicrobial, antidiabetic, antioxidant, and anticancer. Punica granatum fruit extract has traditional uses, however, the anti-cancer activity of purified lectin isolated from P. granatum pulp is yet to be reported.

OBJECTIVE

The goals of this study are purification, characterization of the lectin from P. granatum, and examination of the purified lectin's anticancer potential.

METHODS

Diethylaminoethyl (DEAE) ion-exchange chromatography was used to purify the lectin, and SDSPAGE was used to check the purity and homogeneity of the lectin. Spectrometric and chemical analysis were used to characterize the lectin. The anticancer activity of the lectin was examined using in vivo and in vitro functional assays.

RESULTS

A lectin, designated as PgL of 28.0 ± 1.0 kDa molecular mass, was isolated and purified from the pulps of P. granatum and the lectin contains 40% sugar. Also, it is a bivalent ion-dependent lectin and lost its 75% activity in the presence of urea (8M). The lectin agglutinated blood cells of humans and rats, and sugar molecules such as 4-nitrophenyl-α-D-manopyranoside and 2- nitrophenyl -β- D-glucopyranoside inhibited PgL's hemagglutination activity. At pH ranges of 6.0-8.0 and temperature ranges of 30°C -80°C, PgL exhibited the highest agglutination activity. In vitro MTT assay showed that PgL inhibited Ehrlich ascites carcinoma (EAC) cell growth in a dose-dependent manner. PgL exhibited 39 % and 58.52 % growth inhibition of EAC cells in the mice model at 1.5 and 3.0 mg/kg/day (i.p.), respectively. In addition, PgL significantly increased the survival time (32.0 % and 49.3 %) of EAC-bearing mice at 1.5 and 3.0 mg/kg/day doses (i.p.), respectively, in comparison to untreated EAC-bearing animals (p < 0.01). Also, PgL reduced the tumor weight of EAC-bearing mice (66.6 versus 39.13%; p < 0.01) at the dose of 3.0 mg/kg/day treatment. Furthermore, supplementation of PgL restored the haematological parameters toward normal levels deteriorated in EAC-bearing animals by the toxicity of EAC cells.

CONCLUSION

The results indicated that the purified lectin has anticancer activity and has the potential to be developed as an effective chemotherapy agent.

Recombinant Phaseolus vulgaris phytohemagglutinin L-form expressed in the Bacillus brevis exerts in vitro and in vivo anti-tumor activity through potentiation of apoptosis and immunomodulation

Leukocyte phytohemagglutinin (PHA-L) is a tetrameric isomer of phytohemagglutinin (PHA) purified from the red kidney bean (Phaseolus vulgaris) and is a well-known human lymphocyte mitogen. Due to its antitumor and immunomodulatory effects, PHA-L may serve as a potential antineoplastic agent in future cancer therapeutics. However, various negative consequences of PHA have been reported in the literature as a result of the restricted acquisition methods, including oral toxicity, hemagglutinating activity, and immunogenicity. There is a critical need to explore a new method to obtain PHA-L with high purity, high activity and low toxicity. In this report active recombinant PHA-L protein was successfully prepared by Bacillus brevius expression system, and the antitumor and immunomodulatory activities of recombinant PHA-L were characterized by in vitro and in vivo experiments. The results showed that recombinant PHA-L protein had stronger antitumor effect, and its anti-tumor mechanism was realized through direct cytotoxicity and immune regulation. Importantly, compared with natural PHA-L, the recombinant PHA-L protein showed the lower erythrocyte agglutination toxicity in vitro and immunogenicity in mice. Altogether, our study provides a new strategy and important experimental basis for the development of drugs with dual effects of immune regulation and direct antitumor activity.

Recent advances in the use of legume lectins for the diagnosis and treatment of breast cancer

Poor lifestyle choices and genetic predisposition are factors that increase the number of cancer cases, one example being breast cancer, the third most diagnosed type of malignancy. Currently, there is a demand for the development of new strategies to ensure early detection and treatment options that could contribute to the complete remission of breast tumors, which could lead to increased overall survival rates. In this context, the glycans observed at the surface of cancer cells are presented as efficient tumor cell markers. These carbohydrate structures can be recognized by lectins which can act as decoders of the glycocode. The application of plant lectins as tools for diagnosis/treatment of breast cancer encompasses the detection and sorting of glycans found in healthy and malignant cells. Here, we present an overview of the most recent studies in this field, demonstrating the potential of lectins as: mapping agents to detect differentially expressed glycans in breast cancer, as histochemistry/cytochemistry analysis agents, in lectin arrays, immobilized in chromatographic matrices, in drug delivery, and as biosensing agents. In addition, we describe lectins that present antiproliferative effects by themselves and/or in conjunction with other drugs in a synergistic effect.

Biosensor Characterization from Cratylia mollis Seed Lectin (Cramoll)-MOF and Specific Carbohydrate Interactions in an Electrochemical Model

Biosensors are small devices known for their selectivity, high specificity and sensitivity to the respective analyte, at low concentrations. We developed an electrochemical biosensor using the crystalline polymer MOF-[Cu3 (BTC)2 (H2 O)2 ]n to characterize Cratylia mollis seed lectin (Cramoll) and its interaction with free carbohydrate (glucose) and carbohydrates on the surface of rabbit erythrocytes. The electrochemical potentials presented by the exponential curves that vary from 96 to 142 mV in relation to concentrations of 10 to 20 mM of glucose are decisive for the use of the system containing gold electrode/MOF/Cramoll for the characterization of biological models due to its high sensitivity. As well as the kinetic behavior presented in the cyclic voltammograms, with a cathodic current response of 0.000 3 A for a glucose concentration of 15 mM. These results were due to the high specificity of Cramoll under these conditions, promoting stability of surface charges at the Cramoll/electrode interface. This phenomenon facilitates the monitoring of the interaction with free glucose present in the electrolyte medium by potentiometric and amperometric methods and with carbohydrates present on the surface of rabbit erythrocytes through the potentiometric method. Through scanning electron microscopy (SEM) it was possible to observe Cramoll immobilized on the MOF surface, proving the specificity of the ligand (glucose-lectin) through the morphological lectin changes in this process. This electrochemical model, Cramoll/MOF biosensor, is effective for evaluating free lectin/carbohydrate or in the erythrocyte membrane.

Concanavalin A promotes angiogenesis and proliferation in endothelial cells through the Akt/ERK/Cyclin D1 axis

CONTEXT

Concanavalin A (Con A) exhibited multiple roles in cancer cells. However, the role of Con A in endothelial cells was not reported.

OBJECTIVE

Our present study investigated the potential angiogenic role of Con A in endothelial cells and ischaemic hind-limb mice.

MATERIALS AND METHODS

Human umbilical vein endothelial cells and Ea.hy926 cells were employed to determine the effect of Con A (0.3, 1, and 3 μg/mL) or vehicle on angiogenesis and cell proliferation with tube formation, ELISA, flow cytometry, EdU, and western blot. Hind-limb ischaemic mice were conducted to determine the pro-angiogenic effect of Con A (10 mg/kg) for 7 days.

RESULTS

Con A promoted tube formation to about three-fold higher than the control group and increased the secretion of VEGFa, PDGFaa, and bFGF in the medium. The cell viability was promoted to 1.3-fold by Con A 3 μg/mL, and cell cycle progression of G0G1 phase was decreased from 77% in the vehicle group to 70% in Con A 3 μg/mL, G2M was promoted from 15 to 19%, and S-phase was from 7 to 10%. Con A significantly stimulated phosphorylation of Akt and ERK1/2 and expression of cyclin D1 and decreased the expression of p27. These effects of Con A were antagonised by the PI3K inhibitor LY294002 (10 μM) and MEK pathway antagonist PD98059 (10 μM). Moreover, Con A (10 mg/kg) exhibited a repair effect in ischaemic hind-limb mice.

DISCUSSION AND CONCLUSIONS

This study will provide a new option for treating ischaemic disease by local injection with Con A.

Glycan detecting tools developed from the Clostridium botulinum whole hemagglutinin complex

Lectins are proteins with the ability to recognize and bind to specific glycan structures. These molecules play important roles in many biological systems and are actively being studied because of their ability to detect glycan biomarkers for many diseases. Hemagglutinin (HA) proteins from Clostridium botulinum type C neurotoxin complex; HA1, HA2, and HA3 are lectins that aid in the internalization of the toxin complex by binding to glycoproteins on the cell surface. HA1 mutants have been previously reported, namely HA1 W176A/D271F and HA1 N278A/Q279A which are specific to galactose (Gal)/N-acetylgalactosamine (GalNAc) and N-acetylneuraminic acid (Neu5Ac) sugars, respectively. In this study, we utilized HA1 mutants and expressed them in complex with HA2 WT and HA3 WT to produce glycan detecting tools with high binding affinity. Particularly, two types were made: Gg and Rn. Gg is an Alexa 488 conjugated lectin complex specific to Gal and GalNAc, while Rn is an Alexa 594 conjugated lectin complex specific to Neu5Ac. The specificities of these lectins were identified using a glycan microarray followed by competitive sugar inhibition experiments on cells. In addition, we confirmed that Gg and Rn staining is clearly different depending on cell type, and the staining pattern of these lectins reflects the glycans present on the cell surface as shown in enzyme treatment experiments. The availability of Gg and Rn provide us with new promising tools to study Gal, GalNAc, and Neu5Ac terminal epitopes which can aid in understanding the functional role of glycans in physiological and pathological events.

Semi-Quantification of Lectins in Rice (Oryza sativa L.) Genotypes via Hemagglutination

Lectins are unique glycoproteins that react with specific sugar residues on cell surfaces resulting in agglutination. They offer enormous applications in therapeutics, diagnostics, medicine, and agriculture. Rice lectins are naturally expressed during biotic and abiotic stresses suggesting their importance in stress resistance physiology. The objective of this study was to determine the presence and relative concentration of lectins in different accessions of rice obtained from IABGR/NARC Islamabad mainly originated from Pakistan. About 210 rice accessions including 02 local varieties and 05 transgenic seeds were screened for seed lectins using a hemagglutination (HA) assay with 5% Californian bred rabbits’ erythrocytes. A protein concentration of 3–8 mg/100 mg of seed flour was measured for all the rice accessions; the highest was 8.03 mg for accession 7600, while the lowest noted was 3.05 mg for accession 7753. Out of 210 accessions, 106 showed the highest HA activity. These 106 genotypes were further screened for titer analysis and specific activity. The highest titer and specific activity were observed for accession 7271 as 1024 and 236 hemagglutination unit (HAU), respectively. The selected accessions’ relative affinity and HA capability were evaluated using blood from four different sources: human, broiler chicken, local rabbit, and Californian-breed rabbit. The highest HA activity was observed with Californian-breed rabbit RBCs. The lectin assay was stable for about 1–2 h. After the required investigations, the accessions with higher lectin concentration and HA capability could be used as a readily available source of lectins for further characterization and utilization in crop improvement programs.

Trichosanthes dioica seed lectin inhibits Ehrlich ascites carcinoma cells growth in vivo in mice by inducing G0 /G1 cell cycle arrest

Trichosanthes dioica seed lectin (TDSL), having a molecular mass of 57 ± 2 kDa was purified in an alternative way. For the purification process, the galactose-sepharose-4B affinity column was used. The purified TDSL agglutinated human and mouse erythrocytes at the minimum concentration of 8  μg/ml. d-lactose and d-galactose were the most potent inhibitory sugars as observed. The purified lectin was a glycoprotein having 3.0% of a neutral sugar. The lectin exhibited maximum activity up to 60°C and pH range from 7.0 to 10.0 and stable up to 4.0 M urea as tested. The lectin demonstrated mild toxicity when administered against brine shrimp nauplii, and the LC₅₀ value was calculated to be 84.0 µg/ml. Minimum agglutination of Ehrlich ascites carcinoma (EAC) cells caused by the lectin was found at the protein concentration of 1.56 µg/ml. TDSL inhibited 7, 50.2%, and 60.3% of the EAC cells growth in vivo in mice when administered with 0.75, 1.5, and 3.0 mg kg^-1  day^-1 (i.p.), respectively, for five consecutive days. After lectin treatment, red blood cell (RBC) and hemoglobin levels were increased significantly toward the normal compared with EAC cells-bearing control and normal mice. The tumor burden reduced to 29.5% and 67% after treatment with 1.5 and 3.0 mg kg^-1  day^-1 of the lectin. TDSL triggered the cell cycle arrest at the G₀ /G₁ phase, which was observed using flow cytometry. In conclusion, TDSL can be a candidate for the potent anticancer agents that exerts low toxicity toward brine shrimp nauplii. PRACTICAL APPLICATIONS: A 57 ± 2 kDa lectin (designated TDSL) was purified from Trichosanthes dioica seeds using a galactose-sepharose-4B affinity column. The lectin demonstrated mild toxicity and agglutinated Ehrlich ascites carcinoma (EAC) cells. The lectin inhibited 50.2% and 60.3% of the EAC cell growth in vivo in mice when administered with 1.5 and 3.0 mg kg^-1  day^-1 (i.p.), respectively, for five consecutive days. The lectin increased RBC and hemoglobin level toward the normal compared with lectin-treated EAC cells-bearing, EAC cells-bearing control and normal mice. The tumor burden reduced to 29.5% and 67% after treatment with 1.5 and 3.0 mg kg^-1  day^-1 lectin. TDSL triggered the cell cycle arrest at the G₀ /G₁ phase. The lectin can be a candidate for potent anticancer agents.

The Agglutinin of Common Nettle (Urtica dioica L.) Plant Effects on Gene Expression Related to Apoptosis of Human Acute Myeloid Leukemia Cell Line

Treatment of acute myeloid leukemia (AML) requires new drugs as result of a rise in new cases and high disease relapse. Plant lectins with the ability to bind carbohydrates on the cell surface have the potential to treat cancer. Urtica dioica L. agglutinin (UDA) is a low weight lectin with anti-benign prostatic hyperplasia (BPH) impact. Here, we examine the impact of UDA on HL-60 cell line. Cytotoxicity and cytostatic effects were assessed in HL-60 cells treated with UDA and vincristine (positive control). The effects of the lectin on cell cycle phases and cell death mechanism were surveyed by propidium iodide (PI) staining and annexin V/PI, respectively. The activation status of the apoptosis pathway was determined by western blotting. Finally, the expression levels of 84 genes were examined by the Human cancer drug target gene PCR array kit. The results indicated that the increase in UDA concentration inhibited the proliferation of HL-60 cells as well as apoptosis induction. Cell cycle analysis showed that the number of sub G1 cells increased essentially. Experimental observations showed that UDA can induce cell apoptosis through a caspase 9-dependent pathway. The expression changes of 21 genes confirmed the apoptotic events in HL-60 cells treated with UDA. In this, we have presented the first investigation on the cytotoxic and apoptotic effects of a lectin isolated from rhizomes and roots of Urtica dioica L. on human AML cells. Generally, the results suggest that UDA may have therapeutic value for leukemia and would be studied further as a new drug for AML later on.

Concanavalin A induces apoptosis in a dose-dependent manner by modulating thiol/disulfide homeostasis in C6 glioblastoma cells

Glioma is the most common brain tumor. C6 rat glioblastoma cells provide the possibility to the scientist to study brain cancer. Concanavalin A (Con A) has a lot of antitumoral effects, especially over oxidative stress. In the present study, it was aimed to decide the impacts of various doses of Con A on C6 glioblastoma cells regarding cytotoxicity, thiol/disulfide homeostasis, apoptosis, and inflammation. We detected the cytotoxic activity of Con A (from 7.8 to 500 µg/ml) in C6 cells by utilizing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and determined the toxic concentration of Con A. Once the optimal doses were found, the thiol-disulfide homeostasis, levels of total antioxidant and oxidant status (TAS and TOS), malondialdehyde (MDA) and glutathione (GSH), pro-inflammatory cytokines as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), apoptotic proteins as cytochrome c (CYCS), and caspase 3 (CASP3) were measured. Apoptotic and morphological changes in the C6 cells were examined with an inverted microscope and flow cytometry technique. Dose-dependent Con A triggered oxidative damage in the C6 cells, affecting the inflammatory pathway, so reducing proliferation with apoptotic proteins and morphological changes. But especially, Con A increased disulfide formation by disrupting the thiol/disulfide balance in C6 cells. This study revealed that Con A, known as carbohydrate-binding protein, generated oxidative damage, inflammation, and apoptosis in a dose-dependent manner by modulating thiol/disulfide homeostasis in C6 glioblastoma cells.

Anticancer Activity of Lectins from Bauhinia purpurea and Wisteria floribunda on Breast Cancer MCF-7 Cell Lines

BACKGROUND

Individual and collaborative efforts are being made worldwide in search of effective chemical or natural drugs with less severe side-effects for treatment of cancer. Due to the specificity and selectivity properties of lectins for saccharides, several plant lectins are known to induce cytotoxicity into tumor cells.

OBJECTIVE

To study the antiproliferative activity of two N-acetyl galactosamine specific plant lectins from seeds of Bauhinia purpurea and Wisteria floribunda against MCF-7 Breast cancer cell lines.

METHODS

MTT, lactate dehydrogenase (LDH) leakage, reactive oxygen species (ROS), and caspase- 3 assays and flow cytometry for cell cycle analysis were performed.

RESULTS

The agglutinins BPL and WFL; 446 μgml-1 (2.2 μM) and 329 μgml-1 (2.8 μM), respectively caused remarkable concentration-dependent antiproliferative effect on MCF-7. The effect was seen to be a consequence of binding of the lectin to the cell surface and triggering S and G2 phase arrest. Apoptosis induced was found to be associated with LDH leakage, cell cycle arrest and ROS generation. The apoptotic signal was observed to be amplified by activation of caspase-3 resulting in cell death.

CONCLUSION

The study provides a base for detailed investigation and further use of lectins in cancer studies.

Bioaccessibility and In Vitro Intestinal Permeability of a Recombinant Lectin from Tepary Bean (Phaseolus acutifolius) Using the Everted Intestine Assay

Tepary bean (Phaseolus acutifolius) lectins exhibit differential in vitro and in vivo biological effects, but their gastrointestinal interactions and digestion have not yet been assessed. This work aimed to evaluate the changes of a recombinant Tepary bean lectin (rTBL-1) through an in vitro and ex vivo gastrointestinal process. A polyclonal antibody was developed to selectively detect rTBL-1 by Western blot (WB) and immunohistochemical analysis. Everted gut sac viability was confirmed until 60 min, where protein bioaccessibility, apparent permeability coefficient, and efflux ratio showed rTBL-1 partial digestion and absorption. Immunoblot assays suggested rTBL-1 internalization, since the lectin was detected in the digestible fraction. The immunohistochemical assay detected rTBL-1 presence at the apical side of the small intestine, potentially due to the interaction with the intestinal cell membrane. The in silico interactions between rTBL-1 and some saccharides or derivatives showed high binding affinity to sialic acid (-6.70 kcal/mol) and N-acetylglucosamine (-6.10 kcal/mol). The ultra-high-performance liquid chromatography-electron spray ionization-quantitative time-of-flight coupled to mass spectrometry (UHPLC-ESI-QTOF/MS) analysis showed rTBL-1 presence in the gastric content and the non-digestible fraction after intestinal simulation conditions. The results indicated that rTBL-1 partially resisted the digestive conditions and interacted with the intestinal membrane, whereas its digestion allowed the absorption or internalization of the protein or the derivative peptides. Further purification of digestion samples should be conducted to identify intact rTBL-1 protein and digested peptides to assess their physiological effects.

Real-Time Dissecting the Dynamics of Drug Transportation in the Live Brain

Brain diseases are becoming a more and more serious threat to human health. Many critical properties of the transport mechanisms of drugs in live brains remain poorly understood. In this work, single-particle tracking was used to dissect the transport dynamics of wheat germ agglutinin (WGA) in live brain and characterize the geometry and rheology of the extracellular space (ECS). The results revealed that the movements of WGA were influenced by the specific-binding molecules and the nature of the ECS. We further analyzed the mobility behaviors of WGA globally and quantitatively and found that movement of WGA in brain cells of acute slices was an active transport process associated with actin filaments and microtubules. This work paves the way for studies aiming at characterizing the biophysics of drug transport in the context of live brains, which may contribute to developing potential new therapeutic applications for brain diseases.

Preparation and Nanoencapsulation of Lectin from Lepidium sativum on Chitosan-Tripolyphosphate Nanoparticle and Their Cytotoxicity against Hepatocellular Carcinoma Cells (HepG2)

Lectins are the oligomeric sugar-specific glycoprotein of nonimmune origin, are involved in the multiple biological recognition process, and have the capacity to perform a wide variety of physiological functions including antifungal, antiviral, antitumor, and cell agglutination. The main objective of the current study was to prepare lectin protein-loaded chitosan-TPP nanoparticles via ionic gelation methods with different CS/TPP ratios and to investigate anticancer potential against HepG2 cells. The best ratio showed the mean particle size (298.10 ± 1.9 nm, 21.05 ± 0.95 mv) with optimal encapsulation efficiencies of 52.435 ± 0.09%. The cytotoxicity was evaluated against HepG2 cells, and IC₅₀ values obtained were 265 μg/ml for lectin protein and 105 μg/ml for lectin-loaded chitosan-TPP nanoparticles, respectively. The mRNA expression of proliferation markers like GPC3 was significantly decreased in hepatocellular carcinoma cells (HepG2) during lectin protein-loaded chitosan-TPP nanoparticle treatment. Apoptotic genes that indicating a marked increase in expression are Caspase 3, p53, and Bax, while Bcl2 and AFP showed a downregulation of expression after treatment of HepG2 cells with lectin-loaded chitosan-TPP nanoparticles. The preliminary findings of our study highlighted that lectin protein-loaded chitosan-TPP nanoparticles could be a promising anticancer agent.

130 years of Plant Lectin Research

Lectins are proteins with diverse molecular structures that share the ability to recognize and bind specifically and reversibly to carbohydrate structures without changing the carbohydrate moiety. The history of lectins started with the discovery of ricin about 130 years ago but since then our understanding of lectins has dramatically changed. Over the years the research focus was shifted from 'the characterization of carbohydrate-binding proteins' to 'understanding the biological function of lectins'. Nowadays plant lectins attract a lot of attention especially because of their potential for crop improvement and biomedical research, as well as their application as tools in glycobiology. The present review aims to give an overview of plant lectins and their applications, and how the field evolved in the last decades.

Structure and properties of the oyster mushroom (Pleurotus ostreatus) lectin

Pleurotus ostreatus Lectin (POL) is a 353 amino acid chain lectin that can be purified from the fruiting bodies of the very well-known and widely diffused edible oyster mushrooms (P. ostreatus). The lectin has been partially characterized by different groups and, although it was crystallized about 20 years ago, its 3D structure and the details of its interactions with carbohydrates are still unknown. This paper reports the 3D structure and ligand-binding properties of POL. We have determined the X-ray structure of the apo-protein purified from the fruiting bodies of the mushroom and that of the recombinant protein in complex with melibiose to a resolution of about 2 Å. The lectin is a homodimer in which the two polypeptide chains are linked by a disulfide bridge. A POL monomer is composed of two highly homologous β-jellyroll domains each of which containing a calcium-dependent carbohydrate-binding site. A high degree of sequence similarity is observed between the two carbohydrate-binding modules present in each monomer. The structure of the lectin in complex with melibiose reveals that a POL dimer has four calcium-dependent carbohydrate-binding sites. The interaction with sugars in solution has been characterized by isothermal titration calorimetry and saturation transfer difference NMR and it sheds new light on the molecular determinants of POL specificity. The lectin exhibits in vitro antiproliferative effects against human cancer cell lines and presents structural similarity with the prototype member of the CBM67 family, the noncatalytic domain of Streptomyces avermitilis α-rhamnosidase.

Concanavalin A Toxicity Towards Potato Psyllid and Apoptosis Induction in Midgut Cells

Concanavalin A (ConA), a legume lectin, has been drawing increasing attention in recent years concerning its toxicity against insects and its potential application in pest management. In an attempt to evaluate the effect of ConA on potato psyllid (Bactericera cockerelli), an economically important pest of solanaceous crops, the effect of ConA on potato psyllid survival, psyllid gut nuclear morphology, and expression of psyllid caspase genes were evaluated. Our results determined that artificial diet-feeding assays using ConA had deleterious effects on potato psyllids, resulting in significant psyllid mortality following ingestion. We also found that an apoptotic response was induced by ConA in psyllid midgut cells, which was demonstrated by the DNA fragmentation and abnormal nuclear architecture in the midgut cells. Following ConA ingestion, there was also upregulation of caspase genes in the psyllid midguts. Therefore, a key mechanism behind ConA toxicity towards potato psyllid probably involves the induction of apoptosis in midgut cells. This study could provide a better understanding of the mechanisms underlying ConA toxicity in insects and be a stepping stone towards the development of new psyllid control strategies based on plant lectins.

Quantum Dot Labelling of Tepary Bean (Phaseolus acutifolius) Lectins by Microfluidics

Lectins are bioactive proteins with the ability to recognize cell membrane carbohydrates in a specific way. Diverse plant lectins have shown diagnostic and therapeutic potential against cancer, and their cytotoxicity against transformed cells is mediated through the induction of apoptosis. Previous works have determined the cytotoxic activity of a Tepary bean (Phaseolus acutifolius) lectin fraction (TBLF) and its anti-tumorigenic effect on colon cancer. In this work, lectins from the TBLF were additionally purified by ionic-exchange chromatography. Two peaks with agglutination activity were obtained: one of them was named TBL-IE2 and showed a single protein band in two-dimensional electrophoresis; this one was thus selected for coupling to quantum dot (QD) nanoparticles by microfluidics (TBL-IE2-QD). The microfluidic method led to low sample usage, and resulted in homogeneous complexes, whose visualization was achieved using multiphoton and transmission electron microscopy. The average particle size (380 nm) and the average zeta potential (-18.51 mV) were determined. The cytotoxicity of the TBL-IE2 and TBL-IE2-QD was assayed on HT-29 colon cancer cells, showing no differences between them (p ≤ 0.05), where the LC50 values were 1.0 × 10-3 and 1.7 × 10-3 mg/mL, respectively. The microfluidic technique allowed control of the coupling between the QD and the protein, substantially improving the labelling process, providing a rapid and efficient method that enabled the traceability of lectins. Future studies will focus on the potential use of the QD-labelled lectin to recognize tumor tissues.

Discovery of antitumor lectins from rainforest tree root transcriptomes

Glycans are multi-branched sugars that are displayed from lipids and proteins. Through their diverse polysaccharide structures they can potentiate a myriad of cellular signaling pathways involved in development, growth, immuno-communication and survival. Not surprisingly, disruption of glycan synthesis is fundamental to various human diseases; including cancer, where aberrant glycosylation drives malignancy. Here, we report the discovery of a novel mannose-binding lectin, ML6, which selectively recognizes and binds to these irregular tumor-specific glycans to elicit potent and rapid cancer cell death. This lectin was engineered from gene models identified in a tropical rainforest tree root transcriptome and is unusual in its six canonical mannose binding domains (QxDxNxVxY), each with a unique amino acid sequence. Remarkably, ML6 displays antitumor activity that is >105 times more potent than standard chemotherapeutics, while being almost completely inactive towards non-transformed, healthy cells. This activity, in combination with results from glycan binding studies, suggests ML6 differentiates healthy and malignant cells by exploiting divergent glycosylation pathways that yield naïve and incomplete cell surface glycans in tumors. Thus, ML6 and other high-valence lectins may serve as novel biochemical tools to elucidate the glycomic signature of different human tumors and aid in the rational design of carbohydrate-directed therapies. Further, understanding how nature evolves proteins, like ML6, to combat the changing defenses of competing microorganisms may allow for fundamental advances in the way we approach combinatorial therapies to fight therapeutic resistance in cancer.

Pathogenesis of Celiac Disease and Other Gluten Related Disorders in Wheat and Strategies for Mitigating Them

Wheat is a major cereal crop providing energy and nutrients to the billions of people around the world. Gluten is a structural protein in wheat, that is necessary for its dough making properties, but it is responsible for imparting certain intolerances among some individuals, which are part of this review. Most important among these intolerances is celiac disease, that is gluten triggered T-cell mediated autoimmune enteropathy and results in villous atrophy, inflammation and damage to intestinal lining in genetically liable individuals containing human leukocyte antigen DQ2/DQ8 molecules on antigen presenting cells. Celiac disease occurs due to presence of celiac disease eliciting epitopes in gluten, particularly highly immunogenic alpha-gliadins. Another gluten related disorder is non-celiac gluten-sensitivity in which innate immune-response occurs in patients along with gastrointestinal and non-gastrointestinal symptoms, that disappear upon removal of gluten from the diet. In wheat allergy, either IgE or non-IgE mediated immune response occurs in individuals after inhalation or ingestion of wheat. Following a life-long gluten-free diet by celiac disease and non-celiac gluten-sensitivity patients is very challenging as none of wheat cultivar or related species stands safe for consumption. Hence, different molecular biology, genetic engineering, breeding, microbial, enzymatic, and chemical strategies have been worked upon to reduce the celiac disease epitopes and the gluten content in wheat. Currently, only 8.4% of total population is affected by wheat-related issues, while rest of population remains safe and should not remove wheat from the diet, based on false media coverage.

Comparative Study on the Anticancer Drug Potential of a Lectin Purified from Aloe Vera and Aloe-Emodin

Background:

The effect of Aloctin, a lectin purified from Aloe vera leaves, and aloe emodin an anthraquinone glycoside purified from the leaves of the same plant, on several cancer cell lines was investigated.

Methods:

Aloctin was isolated from A. vera leaf skin by ammonium sulphate precipitation and CNBr-Sepharose 4B-ovalbumin affinity chromatography. Specific new ligands for Aloctin were detected as fetuin and avidin by hemagglutination inhibition tests. The cytotoxic effect of Aloctin and aloe emodin on various human cancer cell lines was tested using MTT assay. Imatinib was tested as standard positive control. The mechanism underlying was tested by the Annexin V-FITC/PI test, with flow cytometry.

Results:

The most sensitive cells to Aloctin and aloe emodin treatment, were identified as AGS human gastric adenocarcinoma cells. The effect was concentration dependent. It was shown that this effect does not occur by apoptosis or necrosis. In Aloctin-imatinib combinations studies, Aloctin significantly increased the cytotoxic effect of imatinib in a dose-dependent manner. It is expected that the results of this study will reveal important findings for the future use of A. vera lectin as well as aloe emodin in cancer research and contribution to lectin biochemistry.

Novel drug isolated from mistletoe (1E,4E)-1,7-bis(4-hydroxyphenyl)hepta-1,4-dien-3-one for potential treatment of various cancers: synthesis, pharmacokinetics and pharmacodynamics

(1E,4E)-1,7-Bis(4-hydroxyphenyl)hepta-1,4-dien-3-one (DHDK) is a novel curcuminoid analogue isolated from mistletoe. We report the chemical total synthesis, pharmacokinetics, pharmacodynamics, and toxicity on normal cells, cancer cells, liver and kidney.

In-vivo antiproliferative activity of Morus latifolia leaf and bark extracts against Ehrlich's ascites carcinoma

Cancer is the second death causing disease all over the world and until today 100 different types of cancer have been identified whose treatment methods consist of serious side effects on human body. To reduce the frequency of adverse effects of cancer treatment, nowadays plant derived natural components are getting priority. The plant Morus latifolia is widely available in northern part of Bangladesh. The earlier researches suggested that popular varieties of some Morus sp. like Morus alba, Morus indica etc. have good anti-proliferative activity. Hence, this study was designed to evaluate the anti-proliferative activity of leaf and bark extracts of M. latifolia against Ehrlich's ascites carcinoma (EAC) in vivo. The leaf and bark extracts of M. latifolia were used in several bioassays including Brine shrimp lethality test, hemagglutination activity test, antioxidant activity test, and cell growth inhibition test. Besides, fluorescence microscopy was performed to study apoptotic features in EAC cells, and molecular analysis like real-time PCR were also conducted. The results of Brine shrimp lethality test, hemagglutination activity test, and antioxidant activity assay supported the cell growth inhibition capability of leaf and bark extracts which was confirmed by in vivo cell growth inhibition bioassay. Moreover, the experimental extracts were able to induce cell apoptotis through altering the expression pattern of Bcl-2 and Bax genes. All of the results of this study suggest that several noble compounds are present in M. latifolia plant extracts which are capable for healing cancer cells.

Structure-function and application of plant lectins in disease biology and immunity

Lectins are proteins with a high degree of stereospecificity to recognize various sugar structures and form reversible linkages upon interaction with glyco-conjugate complexes. These are abundantly found in plants, animals and many other species and are known to agglutinate various blood groups of erythrocytes. Further, due to the unique carbohydrate recognition property, lectins have been extensively used in many biological functions that make use of protein-carbohydrate recognition like detection, isolation and characterization of glycoconjugates, histochemistry of cells and tissues, tumor cell recognition and many more. In this review, we have summarized the immunomodulatory effects of plant lectins and their effects against diseases, including antimicrobial action. We found that many plant lectins mediate its microbicidal activity by triggering host immune responses that result in the release of several cytokines followed by activation of effector mechanism. Moreover, certain lectins also enhance the phagocytic activity of macrophages during microbial infections. Lectins along with heat killed microbes can act as vaccine to provide long term protection from deadly microbes. Hence, lectin based therapy can be used as a better substitute to fight microbial diseases efficiently in future.

Mitogen-Induced Interferon Gamma Production in Human Whole Blood: The Effect of Heat and Cations

BACKGROUND

Interferon-gamma release assays (IGRAs) are blood tests used to measure the amount of interferon-γ (IFN-γ) released by T lymphocytes after stimulation by antigens specific for the diagnosis of latent tuberculosis infection. A mitogen serves as a positive control to assess the immune function in IGRAs.

METHODS

This in vitro study was conducted to evaluate IFN-γ production by human whole blood stimulated with heat-treated and/or cation-supplemented phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM), using QuantiFERON-TB Gold Kit ELISA tests.

RESULTS

The optimal concentrations of PWM, Con A and PHA for IGRAs were 2 µg/mL, 5 µg/mL and 10 µg/mL, respectively. The results showed that IFN-γ production in response to PWM was the highest and PHA was the lowest amount. The median values of three mitogens were in the following order: PWM≥Con A≥ positive control>>PHA-P>>negative control. PWM and PHA were heat stable, while Con A was heat sensitive. The mitogen response of lymphocytes to untreated or heat-treated PWM and heat-treated Con A was increased in 1 mM Ca2+-supplemented groups, whereas the response to heat-treated PHA was decreased. Exposure to 1 mM Mg2+ had no effect on untreated or heat-treated PWM, and a concentration of 1 mM Zn2+ inhibited the stimulation of un-treated PWM. We found that calcium supplementation improved the PWM-induced production of IFN-γ.

CONCLUSION

Therefore, PWM is an appropriate mitogen for use as a positive control in IGRAs. It is a potential indicator of cytokine production in the diagnostic as well as research settings, and calcium supplementation improved stimulation.

Surface-imprinted silica particles for Concanavalin A purification from Canavalia ensiformis

Concanavalin A is a representative of the plant protein group known as lectins. Many lectin proteins have useful characteristics for studies on cell division and cell surfaces. In this study, a new adsorbent for the specific separation of Concanavalin A was prepared by applying a silica particle surface imprinting method. First, silica particles were activated via acidic treatment, and then, 3-methacryloyloxypropyl trimethoxysilane (MPTMS) was used for modification. For the preparation of Concanavalin A surface-imprinted silica particles (Con A-MISPs), N-methacryloyl-l-histidine methyl ester (MAH) was used as a functional monomer. The silica particles were characterized using a Zetasizer, scanning electron microscopy equipment (SEM), and Fourier transform infrared spectroscopy (FTIR). The effects of parameters such as the pH, initial concentration of Concanavalin A, and temperature on the adsorption of Concanavalin A were determined. The maximum Concanavalin A adsorption onto Con A-MISPs was observed to be 305.2 mg/g at a pH of 6. The reusability of the Con A-MISPs was approximately 93.5%. The non-imprinted silica particles (NISPs) were prepared in the same manner without Concanavalin A to compare the surface imprinting factor. Selective binding studies were carried out with lysozyme and hemoglobin molecules. The selectivity of the Con A-MISPs was also investigated by isolating Concanavalin A from Canavalia ensiformis. The purity of the Concanavalin A was shown by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE).

MytiLec-1 Shows Glycan-Dependent Toxicity against Brine Shrimp Artemia and Induces Apoptotic Death of Ehrlich Ascites Carcinoma Cells In Vivo

MytiLec-1, a 17 kDa lectin with β-trefoil folding that was isolated from the Mediterranean mussel (Mytilus galloprovincialis) bound to the disaccharide melibiose, Galα(1,6) Glc, and the trisaccharide globotriose, Galα(1,4) Galβ(1,4) Glc. Toxicity of the lectin was found to be low with an LC₅₀ value of 384.53 μg/mL, determined using the Artemia nauplii lethality assay. A fluorescence assay was carried out to evaluate the glycan-dependent binding of MytiLec-1 to Artemia nauplii. The lectin strongly agglutinated Ehrlich ascites carcinoma (EAC) cells cultured in vivo in Swiss albino mice. When injected intraperitoneally to the mice at doses of 1.0 mg/kg/day and 2.0 mg/kg/day for five consecutive days, MytiLec-1 inhibited 27.62% and 48.57% of cancer cell growth, respectively. Antiproliferative activity of the lectin against U937 and HeLa cells was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro in RPMI-1640 medium. MytiLec-1 internalized into U937 cells and 50 μg/mL of the lectin inhibited their growth of to 62.70% whereas 53.59% cell growth inhibition was observed against EAC cells when incubated for 24 h. Cell morphological study and expression of apoptosis-related genes (p53, Bax, Bcl-X, and NF-κB) showed that the lectin possibly triggered apoptosis in these cells.

Apoptosis of cancer cells is triggered by selective crosslinking and inhibition of receptor tyrosine kinases

Receptor tyrosine kinases (RTK) have been the most prevalent therapeutic targets in anti-cancer drug development. However, the emergence of drug resistance toward single target RTK inhibitors remains a major challenge to achieve long-term remissions. Development of alternative RTK inhibitory strategies that bypass drug resistance is much wanted. In the present study, we found that selected cell surface RTKs were inhibited and crosslinked into detergent resistant complexes by oligomeric but not monomeric concanavalin A (ConA). The inhibition of RTKs by ConA led to suppression of pro-survival pathways and induction of apoptosis in multiple cancer cell lines, while overexpression of constitutively activated protein kinase B (AKT) reversed the apoptotic effect. However, major cell stress sensing checkpoints were not influenced by ConA. To our knowledge, selective crosslinking and inhibition of cell surface receptors by ConA-like molecules might represent a previously unidentified mechanism that could be potentially exploited for therapeutic development.

Plant lectins in cancer therapeutics: Targeting apoptosis and autophagy-dependent cell death

Plant lectins are non-immunoglobin in nature and bind to the carbohydrate moiety of the glycoconjugates without altering any of the recognized glycosyl ligands. Plant lectins have found applications as cancer biomarkers for recognizing the malignant tumor cells for the diagnosis and prognosis of cancer. Interestingly, plant lectins contribute to inducing cell death through autophagy and apoptosis, indicating their potential implication in cancer inhibitory mechanism. In the present review, anticancer activities of major plant lectins have been documented, with a detailed focus on the signaling circuit for the possible molecular targeted cancer therapy. In this context, several lectins have exhibited preclinical and clinical significance, driving toward therapeutic potential in cancer treatment. Moreover, several plant lectins induce immunomodulatory activities, and therefore, novel strategies have been established from preclinical and clinical investigations for the development of combinatorial treatment consisting of immunotherapy along with other anticancer therapies. Although the application of plant lectins in cancer is still in very preliminary stage, advanced high-throughput technology could pave the way for the development of lectin-based complimentary medicine for cancer treatment.

A protein nanocontainer targeting epithelial cancers: rational engineering, biochemical characterization, drug loading and cell delivery

The development of drug delivery and imaging tools is a major challenge in human health, in particular in cancer pathologies. This work describes the optimization of a protein nanocontainer, belonging to the lectin protein family, for its use in epithelial cancer diagnosis and treatment. Indeed, it specifically targets a glycosidic marker, the T antigen, which is known to be characteristic of epithelial cancers. Its quaternary structure reveals a large hydrated inner cavity able to transport small therapeutic molecules. Optimization of the nanocontainer by site directed mutagenesis allowed controlling loading and release of confined drugs. Doxorubicin confinement was followed, both theoretically and experimentally, and provided a proof of concept for the use of this nanocontainer as a vectorization system. In OVCAR-3 cells, a human ovarian adenocarcinoma cell line that expresses the T antigen, the drug was observed to be delivered inside late endosomes/lysosomes. These results show that this new type of vectorization and imaging device opens new exciting perspectives in nano-theranostic approaches.

A New Galactose-Specific Lectin from Clerodendrum infortunatum

Background

The ethno-medical significance of Clerodendrum genus raises the interest towards the characterization of its seed lectin by inexpensive and most effective technique.

Objective

The focus of this study is the purification, characterization, and evaluation of the antioxidant and antiproliferative potential of a galactose-specific lectin from Clerodendrum infortunatum L. seeds.

Materials and Methods

The crude extract, homogenized in 6 volumes of the saline containing 10 mM β-mercaptoethanol was subjected to pigment removal by Toyopeal HW-55 column prior to ammonium sulfate fractionation (40-80 %). The crude protein extract was then loaded to the gel filtration column Sephadex G-200 followed by affinity chromatography using activated galactose coupled Sepharose-4B.

Results

The SDS-PAGE analysis showed a single band of about 30 kDa which further determined by MALDI-TOF analysis. The MALDI-TOF spectra revealed that Clerodendrum infortunatum lectin (CIL) is a homo-tetramer of 120 kDa consisting of four identical subunits of 30 kDa. The haemagglutination inhibition assay was done with purified lectin by many sugars, among which N-acetyl-D-galactosmine (NAG), D-galactose and lactose exhibited high inhibition. NAG showed the highest inhibition amongst the tested sugars, having the minimum inhibitory concentration of about 0.97 mM. The lectin exhibited a moderate antioxidant activity with an IC₅₀ value of 6.1 ± 0.1 mg.mL^-1 and induced cell death with IC₅₀ of 82.8 μg.mL^-1 against human gastric cancer cell line, AGS, indicated the potential of CIL for clinical and therapeutic applications.

Conclusion

The present study demonstrated the moderate ability of the CIL to inhibit the growth of human gastric cancer cells, AGS either by causing cytotoxic or anti-proliferative effects. Thus, CIL due to its remarkable properties may be considered as a potential bio-molecule in tumor research and glycobiology.

WITHDRAWN: Purification and characterizations of a new mannose specific lectin from Bangladeshi cultivated sword bean with antiproliferative activities against Ehrlich ascites carcinoma cells in vivo in mice

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Characterization of chickpea (Cicer arietinum L.) lectin for biological activity

Lectins are proteins that are subject of intense investigations. Information on lectin from chickpea (Cicer arietinum L.) with respect to its biological activities are very limited. In this study, we purified lectin from the seeds of chickpea employing DEAE-cellulose and SP-Sephadex ion exchange chromatography and identified its molecular subunit mass as 35 kDa. The free radical scavenging activity of lectin measured by the DPPH assay has IC₅₀ of 0.88 µg/mL. Lectin exerted antifungal activity against Candida krusei, Fusarium oxysporium oxysporium, Saccharomyces cerevisiae and Candida albicans, while antibacterial activity against E. coli, B. subtilis, S. marcescens and P. aeruginosa. The minimum inhibitory concentrations were 200, 240, 160 and 140 µg for C. krusei, F. oxysporium, S. cerevisiae and C. albicans respectively. Lectin was further examined for its antiproliferative potential against cancerous cell line. The cell viability assay indicated a high inhibition activity on Ishikawa, HepG2, MCF-7 and MDA-MB-231 with IC₅₀ value of 46.67, 44.20, 53.58 and 37.46 µg/mL respectively. These results can provide a background for future research into the benefits of chickpea lectin to pharmacological perspective.

Computational and biological characterization of fusion proteins of two insecticidal proteins for control of insect pests

Sucking pests pose a serious agricultural challenge, as available transgenic technologies such as Bacillus thuringiensis crystal toxins (Bt) are not effective against them. One approach is to produce fusion protein toxins for the control of these pests. Two protein toxins, Hvt (ω-atracotoxin from Hadronyche versuta) and onion leaf lectin, were translationally fused to evaluate the negative effects of fusion proteins on Phenacoccus solenopsis (mealybug), a phloem-feeding insect pest. Hvt was cloned both N-terminally (HL) and then C-terminally (LH) in the fusion protein constructs, which were expressed transiently in Nicotiana tabacum using a Potato Virus X (PVX) vector. The HL fusion protein was found to be more effective against P. solenopsis, with an 83% mortality rate, as compared to the LH protein, which caused 65% mortality. Hvt and lectin alone caused 42% and 45%, respectively, under the same conditions. Computational studies of both fusion proteins showed that the HL protein is more stable than the LH protein. Together, these results demonstrate that translational fusion of two insecticidal proteins improved the insecticidal activity relative to each protein individually and could be expressed in transgenic plants for effective control of sucking pests.

Plant protein-based hydrophobic fine and ultrafine carrier particles in drug delivery systems

For thousands of years, plants and their products have been used as the mainstay of medicinal therapy. In recent years, besides attempts to isolate the active ingredients of medicinal plants, other new applications of plant products, such as their use to prepare drug delivery vehicles, have been discovered. Nanobiotechnology is a branch of pharmacology that can provide new approaches for drug delivery by the preparation of biocompatible carrier nanoparticles (NPs). In this article, we review recent studies with four important plant proteins that have been used as carriers for targeted delivery of drugs and genes. Zein is a water-insoluble protein from maize; Gliadin is a 70% alcohol-soluble protein from wheat and corn; legumin is a casein-like protein from leguminous seeds such as peas; lectins are glycoproteins naturally occurring in many plants that recognize specific carbohydrate residues. NPs formed from these proteins show good biocompatibility, possess the ability to enhance solubility, and provide sustained release of drugs and reduce their toxicity and side effects. The effects of preparation methods on the size and loading capacity of these NPs are also described in this review.