Thalidomide as an anti-cancer agent

Thalidomide is a glutamic acid derivative initially introduced as a sedative hypnotic nearly forty years ago. It was withdrawn following numerous reports linking it to a characteristic pattern of congenital abnormalities in babies born to mothers who used the drug for morning sickness. It has gradually been re-introduced into clinical practice over the past two decades, albeit under strict regulation, since it was found to be useful in the management of erythema nodosum leprosum and HIV wasting syndrome. Recognition of its anti-angiogenic effect led to its evaluation in the treatment of various malignancies, where angiogenesis has been shown to play an important role. Numerous clinical trials done over the past four years have confirmed the significant anti-myeloma activity of this drug. It has also shown promise in preliminary trials in the treatment of a variety of different malignant diseases. The mechanisms of its antineoplastic effects continue to be the focus of ongoing research. It has become clear that even though its anti angiogenic effects play a significant role in the anti-tumor activity, there are other properties of this drug which are responsible as well. It also possesses anti-TNF alpha activity, which has led to its evaluation in several inflammatory states. In this concise review, we briefly describe the historical background and pharmacological aspects of this drug. We have concisely reviewed the current knowledge regarding mechanisms of its anti-neoplastic activity and the results of various clinical trials in oncology.     

Reserpine as an uncoupling agent

1. Reserpine, like the uncoupling agent, 2,4-dinitrophenol prevents oxidative phosphorylation but stimulates the rate at which oxygen is reduced.

2. Both reserpine and 2,4-dinitrophenol fail to stimulate oxygen uptake by isolated mitochondria in the presence of arginine.

3. Both 2,4-dinitrophenol and reserpine induce proton permeability in the mitochondrial membrane so that H⁺ is absorbed from the suspending medium.

4. When the reaction system contains reserpine, accumulation of Ca²⁺ by mitochondria is inhibited.

5. Reserpine decreases both ADP:O and P:O ratios which strongly suggest that reserpine is an uncoupling agent.     

Methylene blue as an antimalarial agent

Methylene blue has intrinsic antimalarial activity and it can act as a chloroquine sensitizer. In addition, methylene blue must be considered for preventing methemoglobinemia, a serious complication of malarial anemia. As an antiparasitic agent, methylene blue is pleiotropic: it interferes with hemoglobin and heme metabolism in digestive organelles, and it is a selective inhibitor of Plasmodium falciparum glutathione reductase. The latter effect results in glutathione depletion which sensitizes the parasite for chloroquine action. At the Centre de Recherche en Santé de Nouna in Burkina Faso, we study the combination of chloroquine with methylene blue (BlueCQ) as a possible medication for malaria in endemic regions. A pilot study with glucose-6-phosphate dehydrogenase-sufficient adult patients has been conducted recently.     

Methylene blue as an antimalarial agent

Abstract

Methylene blue has intrinsic antimalarial activity and it can act as a chloroquine sensitizer. In addition, methylene blue must be considered for preventing methemoglobinemia, a serious complication of malarial anemia. As an antiparasitic agent, methylene blue is pleiotropic: it interferes with hemoglobin and heme metabolism in digestive organelles, and it is a selective inhibitor of Plasmodium falciparum glutathione reductase. The latter effect results in glutathione depletion which sensitizes the parasite for chloroquine action. At the Centre de Recherche en Santé de Nouna in Burkina Faso, we study the combination of chloroquine with methylene blue (BlueCQ) as a possible medication for malaria in endemic regions. A pilot study with glucose-6-phosphate dehydrogenase-sufficient adult patients has been conducted recently.     

Phytoestrogen genistein as an anti-staphylococcal agent

The soybean-derived isoflavone genistein has been shown to exert beneficial effects on many disorders, including cancer and cardiovascular diseases. The effects of genistein on mammalian cells are mediated by its abilities to inhibit topoisomerase II and protein tyrosine kinase. In order to examine the potential antibacterial activities of genistein, we incubated the bacteria with various concentrations of this compound for different periods of time and assessed the viable counts. Exposure to genistein exhibited an inhibitory effect on all staphylococcal strains tested, including methicillin-resistant strains. Furthermore, the growth of Streptococcus pasteurianus, Bacillus cereus, and Helicobacter pylori was clearly inhibited by genistein, whereas Escherichia coli growth was not suppressed. Daidzein, which is structurally similar to genistein, but deficient in topoisomerase II inhibitory activity, also inhibited the growth of Staphylococcus aureus, albeit with lower potency than genistein. Our results indicate that genistein exerts potent antibacterial properties in vitro, which are possibly mediated by the stabilization of the covalent topoisomerase II-DNA cleavage complex.     

Drosophila cecropin as an antifungal agent

The effects of Drosophila and Hyalophora cecropins were tested against different fungi, both insect pathogens and fungi from the normal environment of Drosophila. The fungi were generally found to be as susceptible to the cecropins as most bacteria, the only exception being the insect pathogen Beauveria bassiana which is completely resistant. This is also the only fungus tested which is virulent to Drosophila, giving 100% lethality within 5 days after injection. Lethal concentrations of cecropins against other fungi tested ranged between 0.4 and 4 microM. Andropin is less fungicidal than the cecropins, and Drosophila cecropin A is somewhat more potent than cecropin B. Even dense cultures of Saccharomyces cerevisiae can be cleared by micromolar concentrations of cecropin, whereas Geotrichum candidum is unaffected by cecropin when tested in a dense culture.     

Agrobacterium tumefaciens as an agent of disease

Twenty-six years ago it was found that the common soil bacterium Agrobacterium tumefaciens is capable of extraordinary feats of interkingdom genetic transfer. Since this discovery, A. tumefaciens has served as a model system for the study of type IV bacterial secretory systems, horizontal gene transfer and bacterial-plant signal exchange. It has also been modified for controlled genetic transformation of plants, a core technology of plant molecular biology. These areas have often overshadowed its role as a serious, widespread phytopathogen - the primary driver of the first 80 years of Agrobacterium research. Now, the diverse areas of A. tumefaciens research are again converging because new discoveries in transformation biology and the use of A. tumefaciens vectors are allowing the development of novel, effective biotechnology-based strategies for the control of crown gall disease.     

Potential of doxorubicin as an antileishmanial agent.

Doxorubicin, a well characterized anticancer drug, was tested in vitro and in vivo for activity against Leishmania donovani. Activity in vitro was very high against both the promastigote and amastigote forms of this parasite with 50% effective dose (ED50) values on the order of 0.43 microM and 0.86 microM, respectively. An in vivo inhibition of spleen parasite burden up to 95% in an infected mouse model was achieved when a dosage of 625 micrograms doxorubicin/kg body weight/day was given in 4 consecutive doses, which is far less than the toxic dose. These results suggest that doxorubicin is highly active against visceral leishmaniasis and may be considered with second-line therapeutic agents such as amphotericin B and pentamidine.     

The solid-state catalytic isotope exchange of hydrogen in dalargin

A [³H]Dalargin preparation with a molar radioactivity of 52 Ci/mmol was obtained by the high temperature solid-state catalytic isotope exchange (HSCIE) of tritium for hydrogen at 150°C. This tritium-labeled peptide was shown to completely retain its biological activity in the test of binding to opioid receptors from rat brain. The dissociation constant of the Dalargin-opioid receptor complex was found to be 4.3 nM. The dependences of the chemical yield and the molar radioactivity on the reaction time and temperature of HSCIE were determined. The activation energy of the HSCIE reaction for the peptide was calculated to be 32 kcal/mol. The amino acid analysis showed that tritium is distributed between all the amino acid residues of [³H]Dalargin at the HSCIE reaction, with the temperature growth significantly increasing the total tritium incorporation and, especially, enhancing the radioactivity incorporation into aromatic residues.     

Development of an Fn14 agonistic antibody as an anti-tumor agent

TNF-like weak inducer of apoptosis (TWEAK), a tumor necrosis factor (TNF) family ligand with pleiotropic cellular functions, was originally described as capable of inducing tumor cell death in vitro. TWEAK functions by binding its receptor, Fn14, which is upregulated on many human solid tumors. Herein, we show that intratumoral administration of TWEAK, delivered either by an adenoviral vector or in an immunoglobulin Fc-fusion form, results in significant inhibition of tumor growth in a breast xenograft model. To exploit the TWEAK-Fn14 pathway as a therapeutic target in oncology, we developed an anti-Fn14 agonistic antibody, BIIB036. Studies described herein show that BIIB036 binds specifically to Fn14 but not other members of the TNF receptor family, induces Fn14 signaling and promotes tumor cell apoptosis in vitro. In vivo, BIIB036 effectively inhibits growth of tumors in multiple xenograft models, including colon (WiDr), breast (MDA-MB-231) and gastric (NCI-N87) tumors, regardless of tumor cell growth inhibition response observed to BIIB036 in vitro. The anti-tumor activity in these cell lines is not TNF-dependent. Increasing the antigen-binding valency of BIIB036 significantly enhances its anti-tumor effect, suggesting the contribution of higher order cross-linking of the Fn14 receptor. Full Fc effector function is required for maximal activity of BIIB036 in vivo, likely due to the cross-linking effect or tumor killing activity caused by antibody-dependent cell-mediated cytotoxicity. Taken together, the anti-tumor properties of BIIB036 validate Fn14 as a promising target in oncology and demonstrate its potential therapeutic utility in multiple solid tumor indications.Key words: TWEAK, Fn14, monoclonal antibody, agonist, xenograft, apoptosis     

Development of an Fn14 agonistic antibody as an anti-tumor agent

TWEAK, a TNF family ligand with pleiotropic cellular functions, was originally described as capable of inducing tumor cell death in vitro. TWEAK functions by binding its receptor, Fn14, which is up-regulated on many human solid tumors. Herein, we show that intratumoral administration of TWEAK, delivered either by an adenoviral vector or in an immunoglobulin Fc-fusion form, results in significant inhibition of tumor growth in a breast xenograft model. To exploit the TWEAK-Fn14 pathway as a therapeutic target in oncology, we developed an anti-Fn14 agonistic antibody, BIIB036. Studies described herein show that BIIB036 binds specifically to Fn14 but not other members of the TNF receptor family, induces Fn14 signaling, and promotes tumor cell apoptosis in vitro. In vivo, BIIB036 effectively inhibits growth of tumors in multiple xenograft models, including colon (WiDr), breast (MDA-MB-231), and gastric (NCI-N87) tumors, regardless of tumor cell growth inhibition response observed to BIIB036 in vitro. The anti-tumor activity in these cell lines is not TNF-dependent. Increasing the antigen-binding valency of BIB036 significantly enhances its anti-tumor effect, suggesting the contribution of higher order cross-linking of the Fn14 receptor. Full Fc effector function is required for maximal activity of BIIB036 in vivo, likely due to the cross-linking effect and/or ADCC mediated tumor killing activity. Taken together, the anti-tumor properties of BIIB036 validate Fn14 as a promising target in oncology and demonstrate its potential therapeutic utility in multiple solid tumor indications.     

Morroniside cinnamic acid conjugate as an anti-inflammatory agent

A morroniside cinnamic acid conjugate was prepared and evaluated on E-selectin mediated cell–cell adhesion as an important role in inflammatory processes. 7-O-Cinnamoylmorroniside exhibited excellent anti-inflammatory activity (IC₅₀ = 49.3 μM) by inhibiting the expression of E-selectin; further, it was more active than another cinnamic-acid-conjugated iridoid glycoside (harpagoside; IC₅₀ = 88.2 μM), 7-O-methylmorroniside, and morroniside itself. As a result, 7-O-cinnamoylmorroniside was observed to be a potent inhibitor of TNF-α-induced E-selectin expression.     

The use of DPPD (N,N'-diphenyl-P-phenylenediamine) as an anti-inflammatory agent

The anti-oxidant compound, DPPD, was found to be an effctive anti-inflammatory compound by inhibiting carrageenin rat paw edema, adjuvant athritis and serum sickness expression of vascular and renal injury. It is proposed these effects are due to the inhibition of prostaglandin synthesis or fatty acid peroxide formation.     

Pseudomonas aeruginosa phage lysate as an immunobiological agent

A total of 2087 Pseudomonas aeruginosa isolates collected during the period 1994-1997 were used as starting material. Out of 1704 in-patient isolates, 299 strains were selected for the preparation of phage lysates but only five strains provided stable lysates, i.e., maintained the ability to be repeatedly and completely lysed by the appropriate phage in the course of several years. A set of 193 out-patients (189) and water sources (4) isolates failed to yield strains suitable for phage lysate preparation; 190 strains isolated abroad from patients with cystic fibrosis or respiratory infections included three isolates which, despite having a high degree of mucus production, were suitable for lysate preparation. The antigenic pattern of the phage lysates was ascertained by SDS-polyacrylamide gel electrophoresis.