Covalent Isothiocyanate Inhibitors of Macrophage Migration Inhibitory Factor as Potential Colorectal Cancer Treatments.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that has roles in innate and adaptive human immune responses, as well as inflammation. MIF exerts its biological activity by binding to the cell surface receptor CD74 as well as intracellular signalling proteins. MIF also possesses keto-enol tautomerase activity.

Site-Specific Antimicrobial Activity of a Dual-Responsive Ciprofloxacin Prodrug.

Bacterial infections create distinctive microenvironments with a unique mix of metabolites and enzymes compared with healthy tissues that can be used to trigger the activation of antibiotic prodrugs. Here, a single and dual prodrug masking the C3 carboxylate and C7 piperazine of the fluoroquinolone, ciprofloxacin, responsive to nitroreductase (NTR) and/or hydrogen sulfide (HS), was developed. Masking both functional groups reduced the activity of the prodrug against and , increasing its minimum inhibitory concentration (MIC) by ∼512-fold () and ∼8000-fold ( strains), while masking a single group only increased the MIC by ∼128-fold.

Bioactive atropisomers: Unraveling design strategies and synthetic routes for drug discovery.

Atropisomerism, an expression of axial chirality caused by limited bond rotation, is a prominent aspect within the field of medicinal chemistry. It has been shown that atropisomers of a wide range of compounds, including established FDA-approved drugs and experimental molecules, display markedly different biological activities. The time-dependent reversal of chirality in atropisomers poses complexity and obstacles in the process of drug discovery and development.

Synthesis and Biological Evaluation of Aurachin D Analogues as Inhibitors of Cytochrome Oxidase.

A revised total synthesis of aurachin D (), an isoprenoid quinolone alkaloid that targets () cytochrome (cyt-) oxidase, was accomplished using an oxazoline ring-opening reaction. The ring opening enabled access to a range of electron-poor analogues, while electron-rich analogues could be prepared using the Conrad-Limpach reaction. The aryl-substituted and side-chain-modified aurachin D analogues were screened for inhibition of cyt- oxidase and growth inhibition of .

Development of a bioorthogonal fluorescence-based assay for assessing drug uptake and delivery in bacteria.

Bioorthogonal chemistry can facilitate the development of fluorescent probes that can be used to sensitively and specifically detect the presence of biological targets. In this study, such an assay was developed to evaluate the uptake and delivery of antimicrobials into , building on and extending previous work which utilised more resource intensive LCMS detection. The bacteria were genetically engineered to express streptavidin in the periplasmic or cytoplasmic compartments, which was used to localise a bioorthogonal probe (BCN-biotin).

Improving Antibacterial Activity of a HtrA Protease Inhibitor JO146 against : A Novel Approach Using Microfluidics-Engineered PLGA Nanoparticles.

Nanoparticle drug delivery systems have emerged as a promising strategy for overcoming limitations of antimicrobial drugs such as stability, bioavailability, and insufficient exposure to the hard-to-reach bacterial drug targets. Although size is a vital colloidal feature of nanoparticles that governs biological interactions, the absence of well-defined size control technology has hampered the investigation of optimal nanoparticle size for targeting bacterial cells. Previously, we identified a lead antichlamydial compound JO146 against the high temperature requirement A (HtrA) protease, a promising antibacterial target involved in protein quality control and virulence.

SMA-BmobaSNO: an intelligent photoresponsive nitric oxide releasing polymer for drug nanoencapsulation and targeted delivery.

Nitric oxide (NO) is an important biological signalling molecule that acts to vasodilate blood vessels and change the permeability of the blood vessel wall. Due to these cardiovascular actions, co-administering NO with a therapeutic could enhance drug uptake. However current NO donors are not suitable for targeted drug delivery as they systemically release NO.

Design, synthesis and biological evaluation of P2-modified proline analogues targeting the HtrA serine protease in Chlamydia.

High temperature requirement A (HtrA) serine proteases have emerged as a novel class of antibacterial target, which are crucial in protein quality control and are involved in the pathogenesis of a wide array of bacterial infections. Previously, we demonstrated that HtrA in Chlamydia is essential for bacterial survival, replication and virulence. Here, we report a new series of proline (P2)-modified inhibitors of Chlamydia trachomatis HtrA (CtHtrA) developed by proline ring expansion and Cγ-substitutions.

Hydrogen Sulfide-Responsive Bicontinuous Nanospheres.

Block copolymers (BCPs) that can self-assemble into particles and be triggered by disease-specific molecules such as hydrogen sulfide (HS) have the potential to impact on drug delivery, decreasing off-target toxicities while increasing drug efficacy. However, the incorporation of HS-responsive aryl azides into BCPs for self-assembly has been limited by heat, light, and radical sensitivities. In this study, a robust activator regenerated by the electron-transfer atom-transfer radical polymerization reaction was used to synthesize aryl-azide-containing BCPs under ambient conditions.

EGFR-targeted prodrug activation using bioorthogonal alkene-azide click-and-release chemistry.

Epidermal growth factor receptor (EGFR) is overexpressed in many cancers and therefore serves as an excellent target for prodrug activation. Functionalised trans-cyclooctenes (TCO) were conjugated to an EGFR antibody (cetuximab), providing a reagent for pre-targeting and localisation of the bioorthogonal reagent. The TCOs react with a 4-azidobenzyl carbamate doxorubicin prodrug via a [3 + 2]-cycloaddition and subsequent self-immolation leads to release of doxorubicin (click-and-release).

Optimization of peptide-based inhibitors targeting the HtrA serine protease in Chlamydia: Design, synthesis and biological evaluation of pyridone-based and N-Capping group-modified analogues.

The obligate intracellular bacterium Chlamydia trachomatis (C. trachomatis) is responsible for the most common bacterial sexually transmitted infection and is the leading cause of preventable blindness, representing a major global health burden. While C.

Self-immolative Linkers in Prodrugs and Antibody Drug Conjugates in Cancer Treatment.

Background: The design of anti-cancer therapies with high anti-tumour efficacy and reduced toxicity continues to be challenging. Anti-cancer prodrug and antibody-drug-conjugate (ADC) strategies that can specifically and efficiently deliver cytotoxic compounds to cancer cells have been used to overcome some of the challenges. The key to the success of many of these strategies is a self-immolative linker, which after activation can release the drug payload.

Synthesis and Biological Evaluation of (-) and (+)-Spiroleucettadine and Analogues.

A second-generation enantiospecific synthesis of spiroleucettadine is described. The original reported antibacterial activity was not observed when the experiment was repeated on the synthetic samples; however, significant anti-proliferative activity was uncovered for both enantiomers of spiroleucettadine. Comparison of the optical rotational data and ORD-CD spectra of both enantiomers and the reported spectrum from the natural source have not provided a definitive answer regarding the absolute stereochemistry of naturally occurring spiroleucettadine.

Liposomes with cyclodextrin channels and polyethyleneimine (PEI) improves cytoplasmic vaccine delivery and induces anti-cancer immune activity in mice.

Cancer vaccines have been developed as an additional method of treatment in the fight against cancer. However, an important barrier to an effective vaccine is the inefficient presentation of exogenous antigen by dendritic cells to cytotoxic CD8 T cells. In this study, DPPC liposomes were modified with channels and loaded with polyethyleneimine (PEI) and 5,6-dimethylxanthenone-4-acetic acid (DMXAA) to produce a vaccine carrier.

Tuning activation and self-immolative properties of the bioorthogonal alkene-azide click-and-release strategy.

We report on a series of 4-azidobenzyloxy-substituted self-immolative linkers which undergo [3 + 2]-cycloaddition (click reaction) with functionalized trans-cyclooctenes (TCOs) at second-order rate constants in the range of 0.017 to 4.9 M-1 s-1.

Tetrafluoroaryl azide as an N-terminal capping group for click-to-dissolve diphenylalanine hydrogels.

The synthesis of a bioorthogonal-responsive low molecular weight diphenylalanine (PhePhe)-based hydrogel that is capped with a 4-azido-2,3,5,6-tetrafluorobenzyl carbamate self-immolative linker is reported. The hydrogelator (AzF-PhePhe) generates a stable hydrogel at 0.1 wt%, and rapidly reacts with the bioorthogonal reagent -cyclooctene (TCO), inducing a gel-to-solution transition.

Controlled Delivery of Nitric Oxide for Cancer Therapy.

Nitric oxide (NO) is a short-lived, endogenously produced, signaling molecule which plays multiple roles in mammalian physiology. Underproduction of NO is associated with several pathological processes; hence a broad range of NO donors have emerged as potential therapeutics for cardiovascular and respiratory disorders, wound healing, the immune response to infection, and cancer. However, short half-lives, chemical reactivity, rapid systemic clearance, and cytotoxicity have hindered the clinical development of most low molecular weight NO donors.

Structure-activity analysis of peptidic Chlamydia HtrA inhibitors.

Chlamydia trachomatis high temperature requirement A (CtHtrA) is a serine protease that performs proteolytic and chaperone functions in pathogenic Chlamydiae; and is seen as a prospective drug target. This study details the strategies employed in optimizing the irreversible CtHtrA inhibitor JO146 [Boc-Val-Pro-Val(OPh)] for potency and selectivity. A series of adaptations both at the warhead and specificity residues P and P yielded 23 analogues, which were tested in human neutrophil elastase (HNE) and CtHtrA enzyme assays as well as Chlamydia cell culture assays.

Alkene-Azide 1,3-Dipolar Cycloaddition as a Trigger for Ultrashort Peptide Hydrogel Dissolution.

An alkene-azide 1,3-dipolar cycloaddition between trans-cyclooctene (TCO) and an azide-capped hydrogel that promotes rapid gel dissolution is reported. Using an ultrashort aryl azide-capped peptide hydrogel (PhePhe), we have demonstrated proof-of-concept where upon reaction with TCO, the hydrogel undergoes a gel-sol transition via 1,2,3-triazoline degradation and 1,6-self-immolation of the generated aniline. The potential application of this as a general trigger in sustained drug delivery is demonstrated through release of encapsulated cargo (doxorubicin).

Honey reduces the metastatic characteristics of prostate cancer cell lines by promoting a loss of adhesion.

Honey has been shown to have a range of therapeutic effects in humans, with anti-inflammatory and anti-bacterial effects among those previously characterised. Here, we examine the possibility of New Zealand thyme, manuka and honeydew honeys, and their major sugar and phenolic components, reducing the development of metastatic cancer. Their activity was examined , in PC3 and DU145 prostate cancer cell lines, through measuring the compounds' effects on the metastatic characteristics of migration, invasion and adhesion.

Poloxamer 407-chitosan grafted thermoresponsive hydrogels achieve synchronous and sustained release of antigen and adjuvant from single-shot vaccines.

Sustained-release vaccine delivery systems may enhance the immunogenicity of subunit vaccines and reduce the need for multiple vaccinations. The aim of this study was to develop a thermoresponsive hydrogel using poloxamer 407-chitosan (CP) grafted copolymer as a delivery system for single-shot sustained-release vaccines. The CP copolymer was synthesized using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxysuccinimide chemistry.

Mechanistic Evaluation of Bioorthogonal Decaging with trans-Cyclooctene: The Effect of Fluorine Substituents on Aryl Azide Reactivity and Decaging from the 1,2,3-Triazoline.

Bioorthogonal prodrug activation/decaging strategies need to be selective, rapid and release the drug from the masking group upon activation. The rates of the 1,3-dipolar cycloaddition between a trans-cyclooctene (TCO) and a series of fluorine-substituted azido-PABC self-immolative spacers caging two model drugs, and subsequent release from the 1,2,3-triazoline are reported. As the number of fluorine substituents on the PABC linker increases from one to four, the rate of cycloaddition increases by almost one order of magnitude.

Proteases and protease inhibitors in infectious diseases.

There are numerous proteases of pathogenic organisms that are currently targeted for therapeutic intervention along with many that are seen as potential drug targets. This review discusses the chemical and biological makeup of some key druggable proteases expressed by the five major classes of disease causing agents, namely bacteria, viruses, fungi, eukaryotes, and prions. While a few of these enzymes including HIV protease and HCV NS3-4A protease have been targeted to a clinically useful level, a number are yet to yield any clinical outcomes in terms of antimicrobial therapy.

Detection of Biosynthetic Precursors, Discovery of Glycosylated Forms, and Homeostasis of Calcitonin in Human Cancer Cells.

The peptide hormone calcitonin is intimately connected with human cancer development and proliferation. Its biosynthesis is reasoned to proceed via glycine-, α-hydroxyglycine-, glycyllysine-, and glycyllysyllysine-extended precursors; however, as a result of the limitations of current analytical methods, until now, there has been no procedure capable of detecting these individual species in cell or tissue samples. Therefore, their presence and dynamics in cancer had not been established.

Stability, Kinetic, and Mechanistic Investigation of 1,8-Self-Immolative Cinnamyl Ether Spacers for Controlled Release of Phenols and Generation of Resonance and Inductively Stabilized Methides.

Three cinnamyl ether spacers (non-methyl, α-methyl, and γ-methyl) for caging of phenols have been synthesized and are physiologically stable. When triggered, the γ-methyl spacer releases phenols (pK 7.8 and 9.