Evaluation of the significance of complement-related genes mutations in atypical postinfectious glomerulonephritis: a pilot study

BACKGROUND

Postinfectious glomerulonephritis with C3-dominant glomerular deposition (C3-PIGN) involves C3-dominant glomerular deposition without immunoglobulin. Atypical C3-PIGN involves persistent hypocomplementemia. We investigated the clinical features and explored complement-related gene mutations in atypical PIGN patients.

METHODS

We enrolled atypical C3-PIGN patients and collected data regarding the clinical presentation and pathological characteristics and follow-up data. We measured the levels of complement associated antibodies and performed whole-exome sequencing (WES) to detect mutations in complement-related genes.

RESULTS

The analysis included six atypical C3-PIGN patients. All patients were antistreptolysin-O (ASO) positive. All patients had varying degrees of hematuria, and four patients had proteinuria. None of the patients were positive for complement-related antibodies. All patients possessed mutations of genes related to the complement pathway, including alternative complement pathway genes-CFI, CFH, CFHR3, CFHR5; the lectin pathway gene-MASP2; and the common complement pathway gene-C8A. The rare variant of CFHR3 has been reported in C3 glomerulonephritis. During 56-73 months of follow-up, the levels of urine markers in three patients recovered within 6 months, and the remaining patients had abnormal urine test results over 12 months. Patients who received glucocorticoid therapy recovered faster.

CONCLUSIONS

Our study suggested that complement-related gene mutations may be an important cause of persistent hypocomplementemia in atypical C3-PIGN patients. In addition to variations in alternate pathway-related genes, we also found variations in lectin pathway-related genes, especially MASP2 genes. Although the overall prognosis was good, atypical C3-PIGN patients exhibited a longer period for recovery. Our results suggested that atypical C3-PIGN patients should receive more medical attention and need testing for mutations in complement-related genes.

Compassionate Use Narsoplimab for Severe Refractory Transplantation-Associated Thrombotic Microangiopathy in Children

Transplant-associated thrombotic microangiopathy (TA-TMA) is a common and potentially severe complication of hematopoietic cell transplantation. TA-TMA-directed therapy with eculizumab, a complement C5 inhibitor, has resulted in a survival benefit in some studies. However, children with TA-TMA refractory to C5 inhibition with eculizumab (rTA-TMA) have mortality rates exceeding 80%, and there are no other known therapies. Narsoplimab, an inhibitor of the MASP-2 effector enzyme of the lectin pathway, has been studied in adults with TA-TMA as first-line therapy with a response rate of 61%. Although there are limited data on narsoplimab use as a second-line agent in children, we hypothesized, that complement pathways proximal to C5 are activated in rTA-TMA, and that narsoplimab may ameliorate rTA-TMA in children. In this single-center study, children were enrolled on single-patient, Institutional Review Board-approved compassionate use protocols for narsoplimab treatment. Clinical complement lab tests were obtained at the discretion of the treating physician, although all patients were also offered participation in a companion biomarker study. Research blood samples were obtained at the time of TA-TMA diagnosis, prior to eculizumab treatment, at the time of refractory TA-TMA diagnosis prior to the first narsoplimab dose, and 2 weeks after the first narsoplimab dose. Single ELISA kits were used to measure markers of complement activation according to the manufacture's instructions. Five children with rTA-TMA received narsoplimab; 3 were in multiorgan failure and 2 had worsening multiorgan dysfunction at the time of treatment. Additional comorbidities at the time of treatment included sinusoidal obstructive syndrome (SOS; n = 3), viral infection (n = 3), and steroid-refractory stage 4 lower gut grade IV acute graft-versus-host disease (aGVHD, n = 3). Two infants with concurrent SOS and no aGVHD had resolution of organ dysfunction; 1 also developed transfusion-independence (complete response), and the other's hematologic response was not assessable in the setting of leukemia and chemotherapy (partial response). One additional patient achieved transfusion independence but had no improvement in organ manifestations (partial response), and 2 patients treated late in the course of disease had no response. Narsoplimab was well tolerated without any attributed adverse effects. Three patients consented to provide additional research blood samples. One patient with resolution of organ failure demonstrated evidence of proximal pathway activation prior to narsoplimab treatment with subsequent declines in Ba, Bb, C3a, and C5a and increases in C3 in both clinical and research lab tests. Otherwise, there was no clear pattern of other complement markers, including MASP-2 levels, after therapy. In this cohort of ill children with rTA-TMA and multiple comorbidities, 3 patients benefited from narsoplimab. Notably, the 2 patients with resolution of organ involvement did not have steroid-refractory aGVHD, which is thought to be a critical driver of TA-TMA. Additional studies are needed to determine which patients are most likely to benefit from narsoplimab and which markers may be most helpful for monitoring lectin pathway activation and inhibition.

Reversal mechanism of multidrug-resistant cancer cells by lectin as chemo-adjuvant and targeted therapy- a systematic review

BACKGROUND

Cancer is characterized as the leading cause of death, and the susceptibility of cancer cells to develop resistance due to long-term exposure to complementary chemotherapeutic treatment is referred to as multidrug resistance cancer cells (MDRC), which is a significant obstacle in the treatment of malignancies. Since complementary medicine lost its effectiveness, the development of potential alternative and novel therapeutic approaches has been elevated to a top priority in recent years. In this context, a bioactive protein lectin from plant and animal sources exhibits an invaluable source of anticancer agents with vast therapeutic potential.

PURPOSE

This manuscript's primary purpose is to enlighten the evidence-based (from 1986 to 2022) possible molecular mechanism of alternative treatment approaches using lectins over the complementary medicines used for cancer treatment.

METHODS

The PRISMA rules have been followed properly and qualitative and quantitative data are synthesized systematically. Articles were identified based on Clinical and preclinical reports published on lectin that investigated the in-depth cellular mechanisms, of reverse drug integrative oncology, as a nano-carried targeted delivery. Articles were systematically screened from 1986 to 2022 and selected based on electronic database searches, Medline (PubMed), Google Scholar, Web of Science, Encyclopaedias, Scopus, and ClinicalTrials.gov database.

RESULTS

The search turned up 4,212 publications from 38 different nations, of which 170 reference articles were used in our analysis, in 16 combination therapy and their mode of action, and 27 clinical trial studies including dosage and mechanism of action were included. Reports from the 30 lectins belonging to 28 different families have been included. The reversal mechanism of lectin and alternative therapy against MDRC is critically screened and according to a few clinical and preclinical reports, lectin can suppress the overexpressing genes like P-53, EGFR, and P-gp, MRP, and ABC transporter proteins associated with intracellular transportation of drugs. Since, the drug efflux mechanism leads to MDRC, in this phenomenon, lectin plays a key role in reversing the efflux mechanism. Few preclinical reports have mentioned that lectin shows synergism in combination with complementary medicine and as a nano drug carrier helps to deliver to the targeted site.

CONCLUSION

We have discussed the alternative therapy using lectin and an in-depth insight into the reversal drug resistance mechanisms to combat MDRC cancer, enhance the efficacy, reduce toxicity and adverse events, and ensure targeted delivery, and their application in the field of cancer diagnosis and prognosis has been discussed. However, further investigation is necessary in drug development and clinical trials which could be helpful to elaborate the reversal mechanism and unlock newer treatment modalities in MDRC cancer.

Therapeutic potential of lectins in the treatment of breast cancer: A review

Breast cancer is one of the most common malignancies and the leading cause of cancer-related deaths in women. There are 3 major subtypes of breast cancer that are distinguished by expression of estrogen or progesterone receptors and ERBB2 gene amplification. The 3 subtypes have different risk profiles and treatment strategies. Abnormal glycosylation is thought to play an important role in the development of the tumorigenic and metastatic phenotype of breast cancer and resistance to therapy. They may also be a potentially attractive target for breast cancer treatment. Proteins such as lectins, a family of carbohydrate-binding proteins found in a variety of organisms from viruses to humans, can specifically interact with abnormally glycosylated carbohydrate residues in cancer cells and induce cytotoxic effects. In recent years, there has been a growing number of research addressing studies demonstrating their antitumorigenic and antimalignant effects. This review summarizes recent findings on lectins from plants, animals, fungi, and bacteria that are potentially therapeutic agents against breast cancer and outlines the basis of their mechanism of action.

Identifying FmlH lectin-binding small molecules for the prevention of Escherichia coli-induced urinary tract infections using hybrid fragment-based design and molecular docking

Nearly 50% of women are affected by urinary tract infections (UTIs) during their lifetimes. The most common agent to cause UTIs is Uropathogenic Escherichia coli (UPEC). UPEC expresses fibers known as chaperone-usher pathway pili with adhesins that specifically bind to receptors as they colonize various host tissues. UPEC uses an F9/Yde/Fml pilus, tipped with FmlH, which interacts with terminal galactoside/galactosaminoside units in glycoproteins in the epithelial cells of the bladder and kidney. The extensive use of traditional antibiotics has led to the rise of various antibiotic-resistant strains of UPEC. An alternative therapeutic approach is to use an anti-adhesion strategy mediated by competitive tight-binding FmlH inhibitors. In the current study, we have applied various computational modeling techniques, including fragment-based e-pharmacophore virtual screening, molecular docking, molecular dynamics simulations and binding free energy calculations for the design of small molecules that exhibit binding to FmlH. Our modeling protocol successfully predicted ligand moieties, such as a thiazole group, which were previously found as components of UPEC adhesin pili inhibitors, thereby validating our designed screening protocol. The screening protocol developed here could be utilized for design of ligands for other homologous protein targets. We also identified several novel galactosaminoside-containing molecules that, according to the computational modeling, are predicted to interact strongly with FmlH and hence we predict will be good FmlH inhibitors. Additionally, we have prepared and supplied a database of ∼190K small molecules obtained from virtual screening, which can serve as an excellent resource for the discovery of novel FmlH inhibitors.

Lectin-Like Oxidized Low-Density Lipoprotein Receptor 1 Inhibition in Type 2 Diabetes: Phase 1 Results

Background Blockade of the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a potentially attractive mechanism for lowering inflammatory and lipid risk in patients with atherosclerosis. This study aims to assess the safety, tolerability, and target engagement of MEDI6570, a high-affinity monoclonal blocking antibody to LOX-1. Methods and Results This phase 1, first-in-human, placebo-controlled study (NCT03654313) randomized 88 patients with type 2 diabetes to receive single ascending doses (10, 30, 90, 250, or 500 mg) or multiple ascending doses (90, 150, or 250 mg once monthly for 3 months) of MEDI6570 or placebo. Primary end point was safety; secondary and exploratory end points included pharmacokinetics, immunogenicity, free soluble LOX-1 levels, and change in coronary plaque volume. Mean age was 57.6/58.1 years in the single ascending doses/multiple ascending doses groups, 31.3%/62.5% were female, and mean type 2 diabetes duration was 9.7/8.7 years. Incidence of adverse events was similar among cohorts. MEDI6570 exhibited nonlinear pharmacokinetics, with terminal half-life increasing from 4.6 days (30 mg) to 11.2 days (500 mg), consistent with target-mediated drug disposition. Dose-dependent reductions in mean soluble LOX-1 levels from baseline were observed (>66% at 4 weeks and 71.61-82.96% at 10 weeks in the single ascending doses and multiple ascending doses groups, respectively). After 3 doses, MEDI6570 was associated with nonsignificant regression of noncalcified plaque volume versus placebo (-13.45 mm3 versus -8.25 mm3). Conclusions MEDI6570 was well tolerated and demonstrated dose-dependent soluble LOX-1 suppression and a pharmacokinetic profile consistent with once-monthly dosing. Registration URL: https://clinicaltrials.gov/; Unique identifier: NCT03654313.

Oncolytic Vaccinia Virus Harboring Aphrocallistes vastus Lectin Inhibits the Growth of Cervical Cancer Cells Hela S3

Aphrocallistes vastus lectin (AVL) is a C-type marine lectin produced by sponges. Our previous study demonstrated that genes encoding AVL enhanced the cytotoxic effect of oncolytic vaccinia virus (oncoVV) in a variety of cancer cells. In this study, the inhibitory effect of oncoVV-AVL on Hela S3 cervical cancer cells, a cell line with spheroidizing ability, was explored. The results showed that oncoVV-AVL could inhibit Hela S3 cells growth both in vivo and in vitro. Further investigation revealed that AVL increased the virus replication, promote the expression of OASL protein and stimulated the activation of Raf in Hela S3 cells. This study may provide insight into a novel way for the utilization of lection AVL.

Algae-Derived Bioactive Molecules for the Potential Treatment of SARS-CoV-2

The recently emerged COVID-19 disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has adversely affected the whole world. As a significant public health threat, it has spread worldwide. Scientists and global health experts are collaborating to find and execute speedy diagnostics, robust and highly effective vaccines, and therapeutic techniques to tackle COVID-19. The ocean is an immense source of biologically active molecules and/or compounds with antiviral-associated biopharmaceutical and immunostimulatory attributes. Some specific algae-derived molecules can be used to produce antibodies and vaccines to treat the COVID-19 disease. Algae have successfully synthesized several metabolites as natural defense compounds that enable them to survive under extreme environments. Several algae-derived bioactive molecules and/or compounds can be used against many diseases, including microbial and viral infections. Moreover, some algae species can also improve immunity and suppress human viral activity. Therefore, they may be recommended for use as a preventive remedy against COVID-19. Considering the above critiques and unique attributes, herein, we aimed to systematically assess algae-derived, biologically active molecules that could be used against this disease by looking at their natural sources, mechanisms of action, and prior pharmacological uses. This review also serves as a starting point for this research area to accelerate the establishment of anti-SARS-CoV-2 bioproducts.

Immunostimulatory and anti-allergic potential of novel heterotrimeric lectin from seeds of Zizyphus mauritiana Lam

Zizyphus mauritiana Lam. seeds (ZMS) have been used medicinally as sedative or hypnotic drugs in most of Asian countries. ZMS has significant benefits to the human health. Therefore, we have evaluated immunomodulatory effect of lectin extracted from these ZMSL in both in vitro and in vivo study. Anaphylaxis is a severe life-threatening allergic reaction and Arthus reaction is deposition of immune complex and complement system activation, so we hypothesized that if ZMSL can protect these severe allergic diseases. We have studied the effect of ZMSL on macrophages and Wistar albino rats and confirmed its protective effect against anaphylaxis and Arthus reaction. Results of this study suggest ZMSL have immunostimulatory and antiallergic activity.

Musa acuminata lectin exerts anti-cancer effects on HeLa and EAC cells via activation of caspase and inhibitions of Akt, Erk, and Jnk pathway expression and suppresses the neoangiogenesis in in-vivo models

In the present study aimed to purify the lectin from the sap of Musa acuminata pseudostem and elucidate the apoptotic and angiogenic molecular mechanism in both in-vitro and in-vivo model. Mannose specific lectin was purified by using mannose affinity column chromatography and analyzed by RP-HPLC, SDS-PAGE, and PAS staining method. Furthermore, the protein was identified by MALDI-MS/MS. MAL effectively agglutinates trypsinized RBCs and showed effective cytotoxicity against various human cancer cell lines. MAL mitigates the cell proliferation, colony formation, cell migration, arrest the cell cycle in the G2/M phase, and induce apoptosis by altering the expression of apoptotic proteins/mRNA level (Bax and Bcl-2) via caspase 8/9, 3 dependent pathway in both in-vitro and in-vivo. Supporting this, in-vivo EAC tumor mice models prove the efficacy of MAL by inducing cell death and inhibiting the neovessel formation by targeting the MVD, inhibition of VEGF secretion, suppressing the expression of MMPs, HIF-1α, Flt-1, Akt, Jnk, and Erk1/2. More importantly, the MAL treatment leads to effective inhibition of tumor growth and an increase in the survivability of EAC mice. Our study summarizes that the MAL having a significant anticancer potential expressively degenerates the tumor development by inducing apoptosis and suppressing neoangiogenesis.

Lectin drug conjugate therapy for colorectal cancer

Drug resistance represents an obstacle in colorectal cancer (CRC) treatment because of its association with poor prognosis. rBC2LCN is a lectin isolated from Burkholderia that binds cell surface glycans that have fucose moieties. Because fucosylation is enhanced in many types of cancers, this lectin could be an efficient drug carrier if CRC cells specifically present such glycans. Therefore, we examined the therapeutic efficacy and toxicity of lectin drug conjugate therapy in CRC mouse xenograft models. The affinity of rBC2LCN for human CRC cell lines HT-29, LoVo, LS174T, and DLD-1 was assessed in vitro. The cytocidal efficacy of a lectin drug conjugate, rBC2LCN-38 kDa domain of pseudomonas exotoxin A (PE38) was evaluated by MTT assay. The therapeutic effects and toxicity for each CRC cell line-derived mouse xenograft model were compared between the intervention and control groups. LS174T and DLD-1 cell lines showed a strong affinity for rBC2LCN. In the xenograft model, the tumor volume in the rBC2LCN-PE38 group was significantly reduced compared with that using control treatment alone. However, the HT-29 cell line showed weak affinity and poor therapeutic efficacy. No significant toxicities or adverse responses were observed. In conclusion, we demonstrated that rBC2LCN lectin binds CRC cells and that rBC2LCN-PE38 significantly suppresses tumor growth in vivo. In addition, the efficacy of the drug conjugate correlated with its binding affinity for each CRC cell line. These results suggest that lectin drug conjugate therapy has potential as a novel targeted therapy for CRC cell surface glycans.

Safety and Efficacy of Avaren-Fc Lectibody Targeting HCV High-Mannose Glycans in a Human Liver Chimeric Mouse Model

BACKGROUND & AIMS

Infection with hepatitis C virus (HCV) remains a major cause of morbidity and mortality worldwide despite the recent advent of highly effective direct-acting antivirals. The envelope glycoproteins of HCV are heavily glycosylated with a high proportion of high-mannose glycans (HMGs), which serve as a shield against neutralizing antibodies and assist in the interaction with cell-entry receptors. However, there is no approved therapeutic targeting this potentially druggable biomarker.

METHODS

The anti-HCV activity of a fusion protein consisting of Avaren lectin and the fragment crystallizable (Fc) region of a human immunoglobulin G1 antibody, Avaren-Fc (AvFc) was evaluated through the use of in vitro neutralization assays as well as an in vivo challenge in a chimeric human liver (PXB) mouse model. Drug toxicity was assessed by histopathology, serum alanine aminotransferase, and mouse body weights.

RESULTS

AvFc was capable of neutralizing cell culture-derived HCV in a genotype-independent manner, with 50% inhibitory concentration values in the low nanomolar range. Systemic administration of AvFc in a histidine-based buffer was well tolerated; after 11 doses every other day at 25 mg/kg there were no significant changes in body or liver weights or in blood human albumin or serum alanine aminotransferase activity. Gross necropsy and liver pathology confirmed the lack of toxicity. This regimen successfully prevented genotype 1a HCV infection in all animals, although an AvFc mutant lacking HMG binding activity failed.

CONCLUSIONS

These results suggest that targeting envelope HMGs is a promising therapeutic approach against HCV infection, and AvFc may provide a safe and efficacious means to prevent recurrent infection upon liver transplantation in HCV-related end-stage liver disease patients.

Lectins from the Edible Mushroom Agaricus bisporus and Their Therapeutic Potentials

The mushroom Agaricus bisporus secretes biologically active compounds and proteins with benefits for human health. Most reported proteins from A. bisporus are tyrosinases and lectins. Lectins are of therapeutic or pharmaceutical interest. To date, only limited information is available on A. bisporus lectins and lectin-like proteins. No therapeutic products derived from A. bisporus lectin (ABL) are available on the market despite its extensive exploration. Recently, A. bisporus mannose-binding protein (Abmb) was discovered. Its discovery enriches the information and increases the interest in proteins with therapeutic potential from this mushroom. Furthermore, the A. bisporus genome reveals the possible occurrence of other lectins in this mushroom that may also have therapeutic potential. Most of these putative lectins belong to the same lectin groups as ABL and Abmb. Their relationship is discussed. Particular attention is addressed to ABL and Abmb, which have been explored for their potential in medicinal or pharmaceutical applications. ABL and Abmb have anti-proliferative activities toward cancer cells and a stimulatory effect on the immune system. Possible scenarios for their use in therapy and modification are also presented.

A validated ultra-performance LC-MS/MS method for quantifying a novel oral EGFR inhibitor FCN-411 in human plasma

Aim: To investigate the clinical pharmacokinetic profiles of FCN-411, a new EGFR tyrosine kinase inhibitor, an ultra-performance LC-MS/MS method was developed. Methods & results: The method was suitable to determine FCN-411 in plasma due to the fast sample preparation (protein precipitation procedure), a good linear range of 2-500 ng/ml, low amount of sample volume (5 μl) and less run time (4.5 min) for analysis. And it was demonstrated to be acceptable according to the guidelines for bioanalytical assay validation. Conclusion: The method was robust, sensitive and repeatable, and it is ready to be applied to measure FCN-411 in a Phase I clinical pharmacokinetic study.

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.

Lectins as Promising Therapeutics for the Prevention and Treatment of HIV and Other Potential Coinfections

Human immunodeficiency virus-acquired immunodeficiency syndrome (HIV/AIDS) remains a global health problem. Current therapeutics specifically target the viral pathogen at various stages of its life cycle, although complex interactions between HIV and other pathogenic organisms are evident. Targeting HIV and concomitant infectious pathogens simultaneously, both by therapeutic regimens and in prevention strategies, would help contain the AIDS pandemic. Lectins, a ubiquitous group of proteins that specifically bind glycosylated molecules, are interesting compounds that could be used for this purpose, with demonstrated anti-HIV properties. In addition, potential coinfecting pathogens, including other enveloped viruses, bacteria, yeasts and fungi, and protozoa, display sugar-coated macromolecules on their surfaces, making them potential targets of lectins. This review summarizes the currently available findings suggesting that lectins should be further developed to simultaneously fight the AIDS pandemic and concomitant infections in HIV infected individuals.

A Novel Therapeutic Strategy for Pancreatic Cancer: Targeting Cell Surface Glycan Using rBC2LC-N Lectin-Drug Conjugate (LDC)

Various cancers, including pancreatic ductal adenocarcinoma (PDAC), remain intractable even with costly tumor-targeting antibody drugs. Because the outermost coatings of cancer cells are composed of cell-specific glycan layers (glycocalyx), lectins, proteins with glycan-binding potential, were evaluated for possible use as drug carriers in PDAC treatment. A human PDAC cell line with well-to-moderately differentiated properties (Capan-1) was subjected to lectin microarray analysis to identify specific lectin-glycan pairs. The selected lectin was fused with a bacterial exotoxin for the construction of a lectin-drug conjugate (LDC), and its safety and antitumor effects were evaluated. A specific affinity between a recombinant bacterial C-type lectin (rBC2LC-N) and Capan-1 was identified, and its positivity was confirmed in 69 human samples. In contrast to the belief that all lectins mediate harmful hemagglutination, rBC2LC-N did not cause hemagglutination with human erythrocytes and was safely administered to mice. The 50% inhibitory concentration of LDC to Capan-1 (1.04 pg/mL = 0.0195 pmol/L) was 1/1,000 lower than that reported for conventional immunotoxins. The intraperitoneal administration of LDC reduced the tumor weight from 390 to 130.8 mg (P < 0.01) in an orthotopic model and reduced the number of nodules from 48 to 3 (P < 0.001) and improved survival from 62 to 105 days in a peritoneal dissemination model (P < 0.0001). In addition, the effect of LDC was reproduced in nodules from patient-derived PDAC xenografts through intravenous injection. Herein, we show the concept of utilizing lectins as drug carriers to target glycans on the cancer cell surface, highlighting new insights into cancer treatments. Mol Cancer Ther; 17(1); 183-95. ©2017 AACR.

Large-scale Survey of the Impact of Complementary Medicine on Side-effects of Adjuvant Hormone Therapy in Patients with Breast Cancer

BACKGROUND/AIM

The present clinical investigation was performed to confirm the benefit of complementary medicine in patients with breast cancer undergoing adjuvant hormone therapy (HT).

PATIENTS AND METHODS

The patients (n=1561) were treated according to international guidelines. All patients suffered from arthralgia and mucosal dryness induced by the adjuvant HT. In order to reduce the side-effects, the patients were complementarily treated with a combination of sodium selenite, proteolytic plant enzymes (bromelaine and papain) and Lens culinaris lectin. On case report formulas, self assessment arthralgia and mucosal dryness were documented before and four weeks after complementary treatment. Validation was carried-out by scoring from 1 (no side-effects/optimal tolerability) to 6 (extreme side-effects/extremely poor tolerability). A total of 1,165 patients suffering from severe side-effects (symptom scores >3) were enrolled in this investigation.

RESULTS

Overall, 62.6% of patients (729 out of 1,165) suffering from severe arthralgia and 71.7% of patients (520 out of 725) with severe mucosal dryness significantly benefited from complementary medicine. Mean scores of symptoms declined from 4.83 before treatment to 3.23 after four weeks of treatment for arthralgia and from 4.72 before treatment to 2.99 after four weeks of treatment for mucosal dryness, the primary aims of the present investigation. The reduction of side-effects of HT was statistically significant (p<0.001) after four weeks.

CONCLUSION

This investigation confirms studies suggesting a benefit of complementary treatment with the combination of sodium selenite, proteolytic enzymes and L. culinaris lectin in patients with breast cancer.

Inhibition of Oxidative Stress and Enhancement of Cellular Activity by Mushroom Lectins in Arsenic Induced Carcinogenesis

Chronic arsenicosis is a major environmental health hazard throughout the world, including India. Animals and human beings are affected due to drinking of arsenic contaminated ground water, due to natural mineral deposits, arsenical pesticides or improperly disposed arsenical chemicals. Arsenic causes cancer with production of free radicals and reactive oxygen species (ROS) that are neutralized by an elaborate antioxidant defense system consisting of enzymes and numerous non-enzymatic antioxidants. Dietary antioxidant supplements are useful to counteract the carcinogenesis effects of arsenic. Oyster mushroom lectins can be regarded as ingredients of popular foods with biopharmaceutical properties. A variety of compounds have been isolated from mushrooms, which include polysaccharides and polysaccharopeptides with immune-enhancing effects. Lectins are beneficial in reducing arsenic toxicity due to anticarcinogenetic roles and may have therapeutic application in people suffering from chronic exposure to arsenic from natural sources, a global problem that is especially relevant to millions of people on the Indian subcontinent.

Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential

An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest.

Marine lectins and their medicinal applications

Marine organisms have been extensively explored for the last several decades as potential sources of novel biologically active compounds, and extensive research has been conducted on lectins. Lectins derived from marine organisms are structurally diverse and also differ from those identified from terrestrial organisms. Marine lectins appear to be particularly useful in some biological applications. They seem to induce negligible immunogenicity because they have a relatively small size, are more stable due to extensive disulfide bridge formation, and have high specificity for complex glyco-conjugates and carbohydrates instead of simple sugars. It is clear that many of them have not yet been extensively studied when compared with their terrestrial counterparts. Marine lectins can be used to design and develop new potentially useful therapeutic agents. This review encompasses recent research on the isolation and identification of marine lectins with potential value in medicinal applications.

Lectins with potential for anti-cancer therapy

This article reviews lectins of animal and plant origin that induce apoptosis and autophagy of cancer cells and hence possess the potential of being developed into anticancer drugs. Apoptosis-inducing lectins encompass galectins, C-type lectins, annexins, Haliotis discus discus lectin, Polygonatum odoratum lectin, mistletoe lectin, and concanavalin A, fucose-binding Dicentrarchus labrax lectin, and Strongylocentrotus purpuratus lectin, Polygonatum odoratum lectin, and mistletoe lectin, Polygonatum odoratum lectin, autophagy inducing lectins include annexins and Polygonatum odoratum lectin.

The cyanobacterial lectin scytovirin displays potent in vitro and in vivo activity against Zaire Ebola virus

The cyanobacterial lectin scytovirin (SVN) binds with high affinity to mannose-rich oligosaccharides on the envelope glycoprotein (GP) of a number of viruses, blocking entry into target cells. In this study, we assessed the ability of SVN to bind to the envelope GP of Zaire Ebola virus (ZEBOV) and inhibit its replication. SVN interacted specifically with the protein's mucin-rich domain. In cell culture, it inhibited ZEBOV replication with a 50% virus-inhibitory concentration (EC50) of 50 nM, and was also active against the Angola strain of the related Marburg virus (MARV), with a similar EC50. Injected subcutaneously in mice, SVN reached a peak plasma level of 100 nm in 45 min, but was cleared within 4h. When ZEBOV-infected mice were given 30 mg/kg/day of SVN by subcutaneous injection every 6h, beginning the day before virus challenge, 9 of 10 animals survived the infection, while all infected, untreated mice died. When treatment was begun one hour or one day after challenge, 70-90% of mice survived. Quantitation of infectious virus and viral RNA in samples of serum, liver and spleen collected on days 2 and 5 postinfection showed a trend toward lower titers in treated than control mice, with a significant decrease in liver titers on day 2. Our findings provide further evidence of the potential of natural lectins as therapeutic agents for viral infections.

Polygonatum cyrtonema lectin induces murine fibrosarcoma L929 cell apoptosis via a caspase-dependent pathway as compared to Ophiopogon japonicus lectin

Galanthus nivalis agglutinin (GNA)-related lectin family, a superfamily of strictly mannose-binding specific lectins, has been well-known to possess several biological functions including apoptosis-inducing activities. However, the precise mechanisms of GNA-related lectins to induce apoptosis remains to be clarified. In this study, we showed that Polygonatum cyrtonema lectin (PCL) and Ophiopogon japonicus lectin (OJL), the two mannose-binding GNA-related lectins, could induce murine fibrosarcoma L929 cell apoptosis. In addition, we found that there was a close link between their sugar-binding and apoptosis-inducing activities. Interestingly, we further confirmed that the mechanism of lectin-induced apoptosis was a caspase-dependent pathway. Moreover, we found that the two lectins could amplify tumor necrosis factor α (TNFα)-induced apoptosis. Taken together, these findings would open a new perspective for GNA-related lectins as potential anti-tumor agents.

Influence of bacterial lectins on some reactions of nonspecific immunity in sarcoma 37 transplanted mice

AIM

To study preventive effect of cytotoxic lectin from Bacillus subtilis B-7025 on the tumor growth and nonspecific immunity in sarcoma 37 transplanted mice.

METHODS

Sarcoma 37 cells were transplanted in Balb/c mice. Cytotoxic lectin (CL) was isolated from cultural fluid of B.subtilis strain B-7025 and inoculated at a dose of 0.2 mg per animal in prophylactic or combined schedule. Functional activity of macrophages was evaluated by NBT-test and the level of cytotoxicity, cytotoxic activity of splenocytes was assayed against K562 cells.

RESULTS

CL administration in prophylactic or combined schedule results in inhibition of sarcoma 37 growth in mice. Stimulating effect of CL on peritoneal macrophages of sarcoma 37-bearing mice, especially at early stages of tumor growth, has been observed. At the late stage of tumor growth, the effect of lectin on cytotoxic activity of spleen mononuclear cells has been registered.

CONCLUSION

Upon the use of lectin from B. subtilis B-7025, positive shifts of antitumor immunity reactions leading to tumor growth inhibition and elevation of average life span of tumor-bearing mice, have been detected.

Potential anti-HIV agents from marine resources: an overview

Human immunodeficiency virus (HIV) infection causes acquired immune deficiency syndrome (AIDS) and is a global public health issue. Anti-HIV therapy involving chemical drugs has improved the life quality of HIV/AIDS patients. However, emergence of HIV drug resistance, side effects and the necessity for long-term anti-HIV treatment are the main reasons for failure of anti-HIV therapy. Therefore, it is essential to isolate novel anti-HIV therapeutics from natural resources. Recently, a great deal of interest has been expressed regarding marine-derived anti-HIV agents such as phlorotannins, sulfated chitooligosaccharides, sulfated polysaccharides, lectins and bioactive peptides. This contribution presents an overview of anti-HIV therapeutics derived from marine resources and their potential application in HIV therapy.

Siglecs as targets for therapy in immune-cell-mediated disease

The sialic-acid-binding immunoglobulin-like lectins (siglecs) comprise a family of receptors that are differentially expressed on leukocytes and other immune cells. The restricted expression of several siglecs to one or a few cell types makes them attractive targets for cell-directed therapies. The anti-CD33 (also known as Siglec-3) antibody gemtuzumab (Mylotarg) is approved for the treatment of acute myeloid leukemia, and antibodies targeting CD22 (Siglec-2) are currently in clinical trials for treatment of B cell non-Hodgkins lymphomas and autoimmune diseases. Because siglecs are endocytic receptors, they are well suited for a 'Trojan horse' strategy, whereby therapeutic agents conjugated to an antibody, or multimeric glycan ligand, bind to the siglec and are efficiently carried into the cell. Although the rapid internalization of unmodified siglec antibodies reduces their utility for induction of antibody-dependent cellular cytotoxicity or complement-mediated cytotoxicity, antibody binding of Siglec-8, Siglec-9 and CD22 has been demonstrated to induce apoptosis of eosinophils, neutrophils and depletion of B cells, respectively. Here, we review the properties of siglecs that make them attractive for cell-targeted therapies.

A novel sialic acid-specific lectin from Phaseolus coccineus seeds with potent antineoplastic and antifungal activities

A novel lectin (PCL) with specificity towards sialic acid was purified from Phaseolus coccineus L. (P. multiflorus willd) seeds using ion exchange chromatography on CM and DEAE-Sepharose, and gel filtration on Sephacryl S-200 column. PCL was a homodimer consisting of 29,831.265 Da subunits as determined by gel filtration and MS. Also, PCL was a non-metalloprotein and its N-terminal 23-amino acid sequence, ATETSFSFQRLNLANLVLNKESS, was determined. Subsequently, MTT method, cell morphological analysis and LDH activity-based cytotoxicity assays demonstrated that PCL was highly cytotoxic to L929 cells and induced apoptosis in a dose-dependent manner. Using caspase inhibitors, a typical caspase-dependent pathway was confirmed. PCL also showed remarkable antifungal activity towards some plant pathogenic fungi. Furthermore, when sialic acid-specific activity was fully inhibited, cytotoxicity and antifungal activity were abruptly decreased, respectively, suggesting a significant correlation between sialic acid-specific site and its bi-functional bioactivities.

[Possible application of lectins in diagnostics and therapy. Part I. Diagnostic application]

Lectins are proteins or glyco-proteins binding selectively and without the involvement of enzymes specific for carbohydrate ligands. Lectins are present in organisms on different levels of evolutionary development and play very important roles in life processes of these organisms. Lectins' functioning mechanism is based on the reaction of glycolysation. In vertebrates, functions of lectins are connected with cell recognition, proliferation control, adhesion, cell differentiation, mechanisms of organ creation, and defense mechanisms. Due to their ability to bind reversibly with specific carbohydrate structures, Lectins have commonly been used as a perfect molecular tool in various disciplines of biology and medicine. With the use of modern methods of lectin affinity chromatography (LAC) and various histochemistry methods, lectins provide practical application during observation of changes occurring in the cell membrane in different stages of physiological and pathological development of human or animal organisms. What is particularly important is lectins' contribution to studies on the isolation and structure of glycoconjugates in clinical pathology (including processes of tumor transformation). Serology was the first discipline of medicine relying on the specific activity of lectins. It had been based on the discoveries (by Rekonen in 1948 and Nowell in 1960) that proved that some lectins are able to bind with human and animal blood group antigens. Another discovery (by Nowell in 1960s) of mitogenic effect of PHA on human lymphocytes made lectins helpful and commonly used in the diagnosis of genetic conditions in several diseases. Proving that lectins bind differently with glycoconjugates of normal and tumor cells and are able to detect subtle neoplastic changes was a clue that lectins can be precious and useful in cancer treatment and diagnostics. For many years lectins inducing apoptosis, with immuno-modulatory or antiproliferative activity and toxic lectins belonging to II-RIP class (Ribosome Inactivating Proteins like viscumin, ricin) have been intensively examined in therapy of various diseases, esp. in cancer. Currently the use of lectins in drug targeting is being examined (lectins as drug-carriers, the preparation of bioadhesive "Second Generation" drug-delivery systems). Paper presents below is an attempt at collecting the latest information on diagnostic and therapeutic application possibilities of lectins.

Antitumor efficacy of autovaccines prepared from chemoresistant tumor cells with the use of lectin OF B. subtilis B-7025

AIM

To study whether immunogenecity of tumor cells may be altered upon the development of cytostatic drug resistance and what is the efficacy of vaccines prepared from such tumor cells.

METHODS

Using immunological methods, the influence of vaccines prepared from Lewis lung carcinoma (LLC) cells, sensitive or resistant to cisplatin, with the use of cytotoxic lectins of B. subtilis B-7025 on the course of tumor development and the main effector reactions of antitumor resistance has been studied.

RESULTS

The vaccine prepared from the cells of chemoresistant LLC and lectines of B. subtilis B-7025 possesses antitumor activity, what is evidenced by the indexes of tumor growth inhibition and increased activity of effector cells of antitumor immunity.

CONCLUSIONS

The antitumor action of vaccines prepared with the use of chemoresistant tumor cells is differing is more pronounced, than in the case of chemosensitive variant.

[Regulation of globotriaosylceramide (Gb3)-mediated signal transduction by rhamnose-binding lectin]

Silurus asotus (catfish) egg lectin (SAL) has potent affinity to Gal alpha-linked carbohydrate chains of not only glycoproteins but also glycosphingolipids such as globotriaosylceramide (Gb3). SAL selectively bound to Gb3 localized in glycosphingolipid-enriched microdomain (GEM) of Gb3-expressing (Gb3(+)) Burkitt's lymphoma cells. Since treatment of Gb3(+) cells with SAL caused an increase in externalization of phosphatidylserine via activation of P-glycoprotein, and apoptotic volume decrease via activation of G-protein activated K(+) channel-1, SAL may function as an inducer of early apoptotic signal; however, neither caspase-8 and -3 activation nor DNA fragmentation was observed. We therefore investigated whether cell proliferation and viability were altered in SAL-treated Raji cells. SAL caused reduction of Raji cell proliferation without cytotoxicity. Although SAL did not induce apoptotic cell death to Gb3-expressing cells, it functionally behaved as a regulator of cell proliferation. SAL activated the suppression system of cell proliferation, such as down-regulation of c-myc and cdk4, and up-regulation of p21 and p27, inducing G1 arrest of the cell cycle, and consequently inhibited cell proliferation of Raji cells. Therefore, we conclude that SAL leads the cells to early apoptotic status but not late apoptotic (necrotic) status via binding to Gb3 existing in GEM, and that this binding is a prerequisite condition to induce cell cycle stop signal.

Lectin conjugates as potent, nonabsorbable CFTR inhibitors for reducing intestinal fluid secretion in cholera

BACKGROUND & AIMS

Inhibitors of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel are predicted to prevent intestinal fluid secretion in cholera. We previously discovered low- affinity glycine hydrazide (GlyH) CFTR inhibitors that block CFTR at its external pore. The goal of this study was to develop potent CFTR inhibitors that are minimally absorbed and washed out of the intestinal lumen for application as antisecretory agents in cholera.

METHODS

GlyH analogs (malonic hydrazides, MalH) were chemically conjugated to various lectins ("MalH-lectin") and purified. CFTR inhibition potency was measured by short-circuit current analysis, mechanism of action by patch-clamp, and antidiarrheal efficacy in closed-loop and suckling mouse models.

RESULTS

By lectin conjugation, we improved CFTR inhibitory potency by approximately 100-fold (to 50 nmol/L) and retarded washout. High-affinity CFTR inhibition was abolished by MalH-lectin heat denaturation, protease digestion, or competition by mannose or unconjugated lectin. Patch-clamp analysis indicated CFTR inhibition by an external pore occlusion mechanism. Fluorescently labeled MalH-lectin remained membrane bound for >6 hours after washout, whereas washout occurred in a few minutes without the lectin. MalH-ConA and MalH-wheat (IC50 50-100 pmol) blocked cholera toxin-induced intestinal fluid secretion in closed intestinal loops in mice and greatly reduced mortality in a suckling mouse model of cholera.

CONCLUSIONS

The high potency of MalH-lectin conjugates results from "anchoring" the CFTR-blocking MalH to cell surface carbohydrates by the lectin. The high-affinity, slow washout, and external site of action of the MalH-lectin conjugates support their further development as antisecretory drugs for enterotoxin-mediated secretory diarrheas.

Concanavalin A induces autophagy in hepatoma cells and has a therapeutic effect in a murine in situ hepatoma model

Concanavalin A (ConA), a lectin with mannose specificity that can induce acute hepatic inflammation, was tested for its therapeutic effect against hepatoma. ConA is cytotoxic or inhibitory to hepatoma cells, which is mediated by the autophagic pathway through mitochondria. Once it was bound to cell membrane glycoproteins, the ConA was internalized and preferentially localized onto the mitochondria. The mitochondria membrane permeability changed, and an autophagic pathway including LC3-II generation, double-layer vesicle, BNIP3 induction, and acidic vesicular organelle formation was induced. Either 3-MA or siRNA for BNIP3 and LC3, but neither beclin-1 nor ATG 5, partially inhibited the ConA-induced cell death. In addition to the autophagy induction, ConA is known to be a T cell mitogen. Using an in situ hepatoma model, ConA can exert an anti-hepatoma therapeutic effect, inhibiting tumor nodule formation in the liver and prolonging survival.

CONCLUSION

ConA can be considered as an anti-hepatoma agent therapeutically because of its autophagic induction and immunomodulating activity. This dual function of ConA provides a novel mechanism for the biological effect of lectin.

The anti-tumor effect of Euchema serra agglutinin on colon cancer cells in vitro and in vivo

Eucheuma serra agglutinin (ESA) is a lectin derived from a marine red alga E. serra and binds specifically to mannose-rich sugar chains. Previous reports have indicated that ESA associates with several cancer cells via sugar chains on cell surfaces and induces apoptotic cell death. In this study, we investigated the effect of ESA on Colon26 mouse colon adenocarcinoma cells both in vitro and in vivo. ESA induced cell death against Colon26 cells in vitro, and the expression of caspase-3 and the translocation of phosphatidylserine in ESA-treated Colon26 cells suggested that this cell death was induced through apoptosis. An intravenous injection of ESA significantly inhibited the growth of Colon26 tumors in BALB/c mice; moreover, DNA fragmentation was detected in tumor cells following ESA treatment. These results indicated that ESA is effective as an anti-cancer drug not only in vitro but also in vivo. The side-effects of ESA were not considered to be serious because the decrease in body weight of the mice injected with it was negligible. These observations suggest that ESA has the potential to be an effective anti-tumor drug.

Fluorescent indolylboronic acids that are useful reporters for the synthesis of boronolectins

Lectins are known to regulate a wide variety of biological processes. Therefore, small molecule mimics of lectins have the potential to be used as novel diagnostic and therapeutic agents. In our combinatorial search for lectin mimics, we are in need a large number of boronic acids that change fluorescent properties upon carbohydrate binding. Along this line, a series of indolylboronic acids have been found to show significant fluorescent property changes upon binding with carbohydrates in 0.1 M phosphate buffer at physiological pH. These boronic acids will be very useful for the synthesis of lectin mimics for biological applications.

Elevation of the efficacy of antitumor vaccine prepared on the base of lectines from B. subtilis B-7025 upon its combined application with probiotics in vivo

The aim of the work was to evaluate in vivo the possible enhancement of efficacy of antitumor vaccine prepared on the base of cytotoxic lectine from B. subtilis B-7025 by its combination with probiotic mixture of Enterococcus faecium K-50 and Saccharomyces cerevisiae 14K or their metabolic products.

MATERIALS AND METHODS

Experiments were carried out on the models of solid sarcoma 37 (S37) and metastatic Lewis lung carcinoma (3LL). Efficacy of treatment was evaluated by parameters of tumor growth, median survival time of experimental animals and volume of metastases.

RESULTS

We have shown that combined application of antitumor vaccine with pro-and/or prebiotic resulted in synergistic effect in the therapy S37-bearing mice, whilst in 3LL-bearing animals application of vaccine along with prebiotic inhibited metastasis by 2-2.5-fold compared to animals treated by vaccine only.

CONCLUSION

Application of pre- and probiotics (E. faecium K-50 and S. cerevisiae) markedly elevates efficacy of antitumor vaccine in vivo.

Advances in Prodrug Design

The background of prodrug design is presented herein as the basis for introducing new and advanced latent systems, taking into account mainly the versatility of polymers and other macromolecules as carriers. PDEPT (Polymer-Directed Enzyme Prodrug Therapy); PELT (Polymer-Enzyme Liposome Therapy); CDS (Chemical Delivery System); ADEPT(Antibody-Directed Enzyme Prodrug Therapy); GDEPT/VDEPT (Gene-Directed Enzyme Prodrug Therapy/Virus-Directed Enzyme Prodrug Therapy); ODDS (Osteotropic Drug Delivery System) and LEAPT (Lectin-directed enzyme-activated prodrug therapy) are briefly described and some examples are given.

Production of salivary immunoglobulin A and suppression of Dermatophagoides pteronyssinus-induced airway inflammation by local nasal immunotherapy

BACKGROUND

Local nasal immunotherapy (LNIT) is an effective immunotherapeutic modality, especially when targeting a single immunodominant peptide from an allergen. However, the working mechanisms of LNIT are poorly understood. We hypothesized that LNIT with a mixture of group 2 allergens of Dermatophagoides pteronyssinus (Der p 2) protein and fungal immunomodulatory peptide (FIP) would generate suppression of Der p-induced airway inflammation through immunoglobulin (Ig) A secretion in the airways.

METHOD

Mice were sensitized with recombinant Der p 2 (rDer p 2) and Der p followed by LNIT with rDer p 2 in conjunction with FIP. After intratracheal challenge with rDer p 2 and Der p, the airway inflammation was determined by analyzing the cell subpopulation and cytokine concentration in the bronchoalveolar lavage fluid. The allergen-specific IgE, IgG2a and IgG in the sera and IgA in the saliva were measured by ELISA.

RESULTS

LNIT with rDer p 2 in conjunction with FIP could downregulate the lymphocyte infiltration in both rDer p 2- and Der p-induced airway inflammation. Both total and specific IgA in the saliva were increased after LNIT. Serum levels of IL-4, IL-10 and specific IgE were reduced and the specific IgG2a and IgG increased after LNIT. After LNIT, there was a reduction of airway hypersensitivity at 30 min after allergen challenge in the rDer p 2-and Der p-sensitized mice, with a significant decrease only in rDer p 2-sensitized mice.

CONCLUSION

LNIT with rDer p 2 in conjunction with FIP was not only able to suppress rDer p 2-induced airway inflammation but also generate suppression of Der p-induced airway inflammation. The simultaneous reduction of IL-4 and IL-10 indicated that IL-10-producing cells were not activated by LNIT. The increment of IgA in the airway might play a role in the prevention of airway inflammation.

[Plant lectins and their effects on cancer]

Recently, there has been increased interest in the potential health benefits of plant lectins, particularly due to their anticancer effect. This updated review discusses literature data published on the anticancer activities of plant lectins and their possible molecular mechanism(s) of action.

Mannose-specific plant lectins from the Amaryllidaceae family qualify as efficient microbicides for prevention of human immunodeficiency virus infection

The plant lectins derived from Galanthus nivalis (Snowdrop) (GNA) and Hippeastrum hybrid (Amaryllis) (HHA) selectively inhibited a wide variety of human immunodeficiency virus type 1 (HIV-1) and HIV-2 strains and clinical (CXCR4- and CCR5-using) isolates in different cell types. They also efficiently inhibited infection of T lymphocytes by a variety of mutant virus strains. GNA and HHA markedly prevented syncytium formation between persistently infected HUT-78/HIV cells and uninfected T lymphocytes. The plant lectins did not measurably affect the antiviral activity of other clinically approved anti-HIV drugs used in the clinic when combined with these drugs. Short exposure of the lectins to cell-free virus particles or persistently HIV-infected HUT-78 cells markedly decreased HIV infectivity and increased the protective (microbicidal) activity of the plant lectins. Flow cytometric analysis and monoclonal antibody binding studies and a PCR-based assay revealed that GNA and HHA do not interfere with CD4, CXCR4, CCR5, and DC-SIGN and do not specifically bind with the membrane of uninfected cells. Instead, GNA and HHA likely interrupt the virus entry process by interfering with the virus envelope glycoprotein. HHA and GNA are odorless, colorless, and tasteless, and they are not cytotoxic, antimetabolically active, or mitogenic to human primary T lymphocytes at concentrations that exceed their antivirally active concentrations by 2 to 3 orders of magnitude. GNA and HHA proved stable at high temperature (50 degrees C) and low pH (5.0) for prolonged time periods and can be easily formulated in gel preparations for microbicidal use; they did not agglutinate human erythrocytes and were not toxic to mice when administered intravenously.

Randomized and Double-Blind Studies – Demands and Reality as Demonstrated by Two Examples of Mistletoe Research

BACKGROUND

Two examples of clinical research with mistletoe extracts were used to demonstrate essential difficulties in carrying out randomized and placebo-controlled trials. STUDY 1: In a randomized, placebo-controlled, double-blind study investigating the immunological effects of mistletoe extract, healthy subjects were asked to state whether, in their estimation, they had been treated with verum or a placebo. Due to the intrinsic effects of the mistletoe therapy--local inflammatory reactions at the injection site--100% of the subjects treated with verum and 77% of those treated with a placebo made a correct assessment of their therapy. Although double-blind trials are preferable from the methodological point of view--above all in QoL research--this study shows that double blinding is barely achievable when the investigated therapy has obvious (side) effects. STUDY 2: A prospective, randomized, multicenter study of a mistletoe therapy complementary to chemotherapy treatment of breast cancer had to be stopped after a period of 28 months, because it proved impossible to recruit more than 16 patients in six large study centers. With regard to this example and to other failed, GCP-compliant clinical trials on mistletoe therapy we describe which factors interfere with successful clinical trials. One important point, especially in the investigation of complementary cancer treatments, is that cancer patients are unwilling to have their treatment determined by randomization. Many cancer patients in Germany have their own point of view, as to whether a complementary treatment could be of benefit to them or not. Faced with a life-threatening disease they wish to determine this part of their treatment themselves.

CONCLUSION

This background elucidates the need for improving the methodology of non-randomized trials to obtain objective and reliable results even in these fields of clinical research.

Production of aralin, a selective cytotoxic lectin against human transformed cells, in callus culture of Aralia elata

Recently we found that aralin, a novel lectin, from Aralia elata selectively induces apoptosis in human virus-transformed and cancer cells compared with normal cells. To overcome the reduction of aralin biosynthesis according to the development of leaves, we established callus tissues from the young shoots. The N-terminal amino acid sequence and immunochemical analyses revealed that ca-aralin, an aralin synthesized in the callus, was structurally identical with aralin except for the glycosylation of the B chain. The selective cytotoxic index (ratio of IC50 value against human lung normal cells versus virus-transformed cells) of ca-aralin was 2-fold higher than that of aralin. Thus, these results suggest that ca-aralin is more useful than aralin as an anticancer agent.

[Human lectins and their correspondent glycans in cell biology and clinical medicine]

Lectins are phylogenetically ancient proteins that have specific recognition and binding functions for complex carbohydrates of glycoconjugates, i. e., of glycoproteins, proteoglycans/glycosaminoglycans and glycolipids. This class of proteins mediates important processes of adhesion and communication both inside and outside cells. A large variety of lectins are expressed in the human organism. This article reviews the current knowledge of human lectins with a focus on biochemistry and pathobiochemistry (principles of protein glycosylation and defects of glycosylation as a basis of disease) and cell biology (protein sorting, exocytosis and endocytosis, apoptosis, cell adhesion, cell differentiation, and malignant transformation). The clinical significance of lectin-glycoconjugate interactions is described by example of inflammatory diseases, defects of immune defense, autoimmunity, infectious diseases, and tumor invasion/metastasis. Moreover, therapeutic perspectives of novel drugs that interfere with lectin-carbohydrate interactions are discussed.

M cell targeting by lectins: a strategy for mucosal vaccination and drug delivery

Bioadhesins are a recognised method of enhancing the absorption of drugs and vaccines at mucosal surfaces. Additionally, bioadhesins allow for cell specific targeting. Lectin-mediated targeting and delivery exploits unique surface carbohydrates on mucosal epithelial cells. The antigen-sampling M cells offer a portal for absorption of colloidal and particulate delivery vehicles, including bacteria, viruses and inert microparticles. We review work supporting the use of lectins to aid targeting to intestinal M cells. Consideration is also given to lectin-mediated targeting in non-intestinal sites and to the potential application of other bioadhesins to enhance M cell transport. While substantial hurdles must be overcome before mucosal bioadhesins can guarantee consistent, safe, effective mucosal delivery, this strategy offers novel opportunities for drug and vaccine formulation.

Drug targeting to the colon with lectins and neoglycoconjugates

Targeting of drugs to specific sites of action provides several advantages over non-targeted drugs. These include the prevention of side effects of drugs on healthy tissues and enhancement of drug uptake by targeted cells. This review will cover traditional approaches of colon drug targeting as well as the use of lectins and neoglycoconjugates for the targeted delivery. Direct and reverse targeting strategies, potential molecular targets and targeting moieties for colon drug delivery, targeted drug delivery systems (DDS) for colon delivery, anticancer DDS targeted to colon cancer are examined. Directions of future development are discussed.

Lectin-mediated drug delivery in the oral cavity

The delivery of therapeutic agents to, or via, the oral cavity is limited by the efficient removal mechanisms that exist in this area. Lectins are proteins or glycoproteins that bind to specific sugar residues, and can, therefore, interact with the glycoconjugates present on cell surfaces or salivary mucins. Endogenous lectins could also be used as points of attachment for carbohydrate-containing delivery systems. This review considers the possibility of using lectins as targeting agents within the oral cavity and reports on some of the limited number of studies completed to date. As lectins are multifunctional molecules, the possibility of using them as both targeting and therapeutic agents is considered. Lectin-containing delivery systems are a potential innovation for targeted and prolonged therapy within the oral cavity, but considerations such as toxicity and cost will need to be addressed before their routine use becomes a reality.

The effects of lectins on indomethacin-induced small intestinal ulceration

Growth factors, such as epidermal growth factor and keratinocyte growth factor, have considerable therapeutic potential for repairing mucosal injury in the intestine when given systemically. Recently, several lectins have been shown to have trophic effects on the intestine when given orally. We examined the effects of phytohaemagglutinin (PHA) and concanavalin A (Con-A) on indomethacin-induced intestinal injury in rat. Five-week-old rats were randomized to four groups (n=5), and intestinal injury was induced by indomethacin injection in three of these groups. Elemental diet (ED) feeding was then commenced. The groups were thus ED feeding/indomethacin untreated (control group), ED feeding/indomethacin treated (ED group), 0.1% PHA-supplemented ED feeding/indomethacin treated (PHA group) and 0.1% Con-A-supplemented ED feeding/indomethacin treated (Con-A group). After 7 days of feeding, macroscopic inflammatory scores, mucosal permeability, myeloperoxidase (MPO) activities and cell proliferation were determined. Macroscopic inflammatory scores, mucosal permeability and MPO activities were significantly lower in both lectin groups than that in control group. Twenty-four hour excretion rate of phenolsulphonphthalein was significantly lower in both lectin groups than that in ED group. Cell proliferation of the small intestine was significantly increased by both lectins. Lectin supplementation can induce ulcer healing following indomethacin-induced damage.

Oral administration of an edible-mushroom-derived protein inhibits the development of food-allergic reactions in mice

BACKGROUND

Food allergy is a common disease without effective treatment. Since strict elimination of food allergens may be difficult, strategies for effective intervention are urgently needed.

OBJECTIVE

The aim was to investigate the prophylactic use of orally administrated FIP-fve, an immunomodulatory protein isolated from the edible mushroom Flammulina velutipes, in a murine model of food allergy.

METHODS

BALB/c mice were immunized twice intraperitoneally with ovalbumin (OVA), at an interval of 2 weeks. Before and during each period of immunization, FIP-fve (200 microg per mouse) or phosphate-buffered saline was given orally every other day with a total of five doses. Then OVA-specific antibodies and cytokine profiles were determined. Subsequently, the mice were orally challenged with OVA. Symptoms of anaphylaxis, levels of plasma histamine, and histology of intestines were examined.

RESULTS

Mice receiving oral FIP-fve treatment during sensitization to OVA had an impaired OVA-specific IgE response with a Th1-predominant cytokine profile. These mice were protected from systemic anaphylaxis-like symptoms induced by subsequent oral challenge with OVA.

CONCLUSION

Oral administration of FIP-fve has a Th1-skewing effect on the development of the allergen-specific immune response, and may serve the purpose of immunoprophylaxis for food allergy and other allergic diseases.