Mitigation of Insulin Resistance by Natural Products from a New Class of Molecules, Membrane-Active Immunomodulators.

Insulin resistance (IR), accompanied by an impaired cellular glucose uptake, characterizes diverse pathologies that include, but are not limited to, metabolic disease, prediabetes and type 2 diabetes. Chronic inflammation associated with deranged cellular signaling is thought to contribute to IR. The key molecular players in IR are plasma membrane proteins, including the insulin receptor and glucose transporter 4. Certain natural products, such as lipids, phenols, terpenes, antibiotics and alkaloids have beneficial effects on IR, yet their mode of action remains obscured. We hypothesized that these products belong to a novel class of bioactive molecules that we have named membrane-active immunomodulators (MAIMs). A representative MAIM, the naturally occurring medium chain fatty acid ester diethyl azelate (DEA), has been shown to increase the fluidity of cell plasma membranes with subsequent downstream effects on cellular signaling. DEA has also been shown to improve markers of IR, including blood glucose, insulin and lipid levels, in humans. The literature supports the notion that DEA and other natural MAIMs share similar mechanisms of action in improving IR. These findings shed a new light on the mechanism of IR mitigation using natural products, and may facilitate the discovery of other compounds with similar activities.

Membrane Active Immunomodulator As a Novel Therapy for an Infectious Bacterial Disease, Buruli Ulcer.

BACKGROUND/AIM: Mycobacterium ulcerans causes the necrotizing skin disease Buruli ulcer (BU), characterized by the formation of subcutaneous lesions and immunosuppression thought to be mediated by the virulence factor mycolactone. Since early BU lesions are typically painless, patients often seek standard oral antibiotic therapy at the advanced stages when the treatment is less effective. Given that currently there is no curative topical treatment for BU, our objective was to evaluate a plasma membrane fluidizer, diethyl azelate (DEA), as a potential novel topical therapy for BU. MATERIALS AND METHODS: We evaluated the effects of DEA against bacterial extracts and live strains of M. ulcerans ATCC 35840 (mycolactone positive; M+) and ATCC 19423 (mycolactone negative; M-) by measuring cytokine levels in cultured cells and tissue extracts using multiplexed immunoassays and numbers of skin lesions as the endpoints. RESULTS: In vitro, DEA counteracted immunosuppression induced by extract from the M+ strain in the 3-D human skin model (EpiDerm) and in human dendritic cells. In vivo, topical DEA reduced immunosuppressive activities of M+ and M- strains at all stages of BU, including advanced ulcers. DEA also diminished lesion formation and ulceration, accelerated healing of skin lesions and preserved normal immune responsiveness to pathogen-associated molecular pattern receptor agonists in blood of infected animals. CONCLUSION: The efficacy of DEA in BU models is linked to overcoming the immunosuppressive activity of virulence factors produced by M. ulcerans. Thanks to its pluripotent activity, DEA is a promising novel treatment for BU and possibly other pathogenic mycobacteria.

Diethyl Azelate for the Treatment of Brown Recluse Spider Bite, a Neglected Orphan Indication.

BACKGROUND/AIM: Brown recluse spider bite releases hemolytic and cytotoxic phospholipase D to the wound that may cause necrosis or even death. We examined diethyl azelate (DEA), a plasma membrane fluidizer with a broad range of immunomodulatory activities, as a potential treatment for the brown recluse spider bite. MATERIALS AND METHODS: Topical DEA was used in emergency to treat brown recluse spider bites in a human subject. We subsequently evaluated the effects of DEA on hemolysis induced by the brown recluse spider venom, recluse recombinant phospholipase D (rPLD), and venoms from honey bee and moccasin snake, and on phospholipase A2 activity in the bee and snake venoms and in human urine. RESULTS: Topical DEA resolved the consequences of human brown recluse spider envenomation in two weeks. In vitro, DEA inhibited hemolysis caused by the brown recluse spider venom and rPLD and suppressed phospholipase A2 activity in a dose-dependent manner. CONCLUSION: DEA is a promising novel therapy for the brown recluse spider bite and perhaps even unrelated envenomations involving PLDs.

Adaptive Membrane Fluidity Modulation: A Feedback Regulated Homeostatic System and Target for Pharmacological Intervention.

BACKGROUND/AIM: Alterations of plasma membrane fluidity are characteristic of many diseases but the intentional modulation of membrane fluidity with drugs has been less studied. We examined the therapeutic potential of the membrane fluidizer diethyl azelate (DEA) and related azelates. MATERIALS AND METHODS: The effects of azelates on plasma membrane fluidity and cell signaling were examined in primary human and murine cells and in vivo. Endpoints were queried using single target and multiplexed immunoassays. RESULTS: Unique membrane-fluidizing properties and biomarker signatures suggest that azelates are not prodrugs. DEA decreased cytokine signaling from pattern recognition receptors in human dendritic cells, disabled membrane attack of cholera toxin in vitro, and prevented immunosuppression by anthrax lethal toxin in vitro and in vivo. In the murine sepsis model, DEA increased survival and reduced organ damage. CONCLUSION: Azelates represent a new class of drugs, membrane active immunomodulators, which target an innate homeostatic mechanism, adaptive membrane fluidity modulation.

Adaptive Membrane Fluidity Modulation: A Feedback Regulated Homeostatic System Hiding in Plain Sight.

The structure of the plasma membrane affects its function. Changes in membrane fluidity with concomitant effects on membrane protein activities and cellular communication often accompany the transition from a healthy to a diseased state. Although deliberate modulation of membrane fluidity with drugs has not been exploited to date, the latest data suggest the "druggability" of the membrane. Azelaic acid esters (azelates) modulate plasma membrane fluidity and exhibit a broad range of immunomodulatory effects in vitro and in vivo. Azelates represent a new class of drugs, membrane active immunomodulators (MAIMs), which use the entire plasma membrane as the target, altering the dynamics of an innate feedback regulated homeostatic system, adaptive membrane fluidity modulation (AMFM). A review of the literature data spanning >200 years supports the notion that molecules in the MAIMs category including known drugs do exert immunomodulatory effects that have been either neglected or dismissed as off-target effects.

Oral Azelaic Acid Ester Decreases Markers of Insulin Resistance in Overweight Human Male Subjects.

BACKGROUND/AIM: Insulin resistance (IR) is linked to increased risk of cardiovascular disease and cancer. We examined safety and efficacy of the natural product diethyl azelate (DEA) in overweight males with a varying degree of IR. PATIENTS AND METHODS: Seventeen subjects [age 18-42, hemoglobin A1c (A1c) of 5.2-6.2%] received orally 1 mg/kg DEA daily for 21 days. Blood plasma glucose, insulin and lipid levels were assessed before and after treatment. RESULTS: DEA was well tolerated without hypoglycemia or adverse effects except transient diarrhea (n=1). DEA significantly reduced fasting glucose by 6.06 mg/dl (n=8) and insulin by 37.8% (n=8) in subjects with IR and/or A1c ≥5.6%. Furthermore, it improved cholesterol/HDL, LDL/HDL, and non-cholesterol HDL/HDL by 5.4, 6.5, and 6.6%, respectively in all subjects, and by 8.0, 9.8, and 9.8%, respectively in 9 subjects with A1c ≥5.6%. CONCLUSION: DEA efficacy correlates with the degree of IR. DEA holds promise as a novel treatment for the management of IR.

Development and antitumor activity of a BCL-2 targeted single-stranded DNA oligonucleotide.

PNT100 is a 24-base, chemically unmodified DNA oligonucleotide sequence that is complementary to a region upstream of the BCL-2 gene. Exposure of tumor cells to PNT100 results in suppression of proliferation and cell death by a process called DNA interference. PNT2258 is PNT100 that is encapsulated in protective amphoteric liposomes developed to efficiently encapsulate the PNT100 oligonucleotide, provide enhanced serum stability, optimized pharmacokinetic properties and antitumor activity of the nanoparticle both in vivo and in vitro. PNT2258 demonstrates broad antitumor activity against BCL-2-driven WSU-DLCL2 lymphoma, highly resistant A375 melanoma, PC-3 prostate, and Daudi-Burkitt's lymphoma xenografts. The sequence specificity of PNT100 was demonstrated against three control sequences (scrambled, mismatched, and reverse complement) all encapsulated in a lipid formulation with identical particle characteristics, and control sequences did not demonstrate antiproliferative activity in vivo or in vitro. PNT2258 is currently undergoing clinical testing to evaluate safety and antitumor activity in patients with recurrent or refractory non-Hodgkin's lymphoma and additional studies are planned.

Plasma biomarkers distinguish non-small cell lung cancer from asthma and differ in men and women.

BACKGROUND: Lung cancer (LC) is the leading cause of deaths caused by cancer worldwide. A diagnostic test for LC is needed for monitoring high-risk populations. PATIENTS AND METHODS: Fifty-seven markers were measured using multiplex immunoassays of plasma of patients with non-small cell lung cancer (NSCLC); (245 men, 114 women, 1 unknown), asthma (67 men, 111 women, 2 unknown) and of healthy controls (165 men, 122 women, 1 unknown). Mass spectrometry was used for biomarker discovery. A support vector machine (SVM) was used for data analysis. RESULTS: When all biomarkers and both genders were co-analyzed, SVM classified NSCLC and asthma with an accuracy of 0.94. Restricting to NSCLC versus healthy using best subsets of variables (males: epidermal growth factor (EGF), interleukin-8 (IL-8), soluble Fas (sFas), matrix metalloproteinase-9 (MMP-9), plasminogen activator inhibitor-1 (PAI-1); females: EGF, soluble cluster of differentiation 40 (sCD40) ligand, IL-8) yielded sensitivity and specificity of 1. Expression of eleven mass spectrometric biomarkers differed between pathologies. CONCLUSION: Significant inter-pathology and gender differences between biomarkers may improve diagnosis of LC.

Effects of alpha-difluoromethylornithine on markers of proliferation, invasion, and apoptosis in breast cancer.

AIM: To examine changes in biomarkers expressed in breast tumors in response to patient treatment with the polyamine synthesis inhibitor alpha-difluoromethylornithine (DFMO). PATIENTS AND METHODS: The expression of Ki-67 (MIB-1), matrix metalloproteinases (MMP) 2 and 9, urokinase-type plasminogen activator (uPA) were examined by immunohistochemistry in breast tissue specimens (controls: n=15, 13 evaluable, and DFMO group; n=27, 21 evaluable). Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). RESULTS: Significant increases in apoptosis, MMP-9 and uPA (tumor) were observed in 7 patients >or=50 years who received DFMO for >or=14 days relative to patients <50 years and/or who received <14 days of treatment (n=11). No other measured characteristics, including tumor estrogen and progesterone receptor status, hormone replacement therapy history, histopathological characteristics or tumor grade were correlated with these biomarker changes. CONCLUSION: Unexpected correlation of proapoptotic DFMO activity in postmenopausal women with breast cancer warrants further study.

Regulation of tumor signaling pathways by AZD3409 in vitro.

BACKGROUND: The antineoplastic activity of AZD3409 was evaluated in relation to paclitaxel in human breast (MDA-MB-231, BT-474) and ovarian (A2780, A2780cp) cancer cell lines. Biomarkers of apoptosis, protein prenylation, survival, angiogenesis and cellular growth were determined. MATERIALS AND METHODS: Cytotoxicity was evaluated by MTS assay, and apoptosis was evaluated by TUNEL. Biomarkers were measured by Western blots and ELISA. RESULTS: The IC50 concentrations of AZD3409 in MDA-MB-231, BT-474, A2780 and A2780cp were 19.16, 5.69, 3.19, and 8.86 microM, respectively. The corresponding apoptogenic EC50 concentrations were 6.81, 4.15, 1.54 and 4.59 microM. CONCLUSION: Famesylation of HDJ-2 was inhibited in all cell lines. Secretion of VEGF, bFGF and MMP-1 were inhibited in the breast lines but augmented in the ovarian lines. AZD3409 increased Akt activation in breast lines and decreased it in ovarian lines, without effect on MEK or ERK activation. AZD3409 cytotoxicity is mediated in part by inhibition of farnesylation.