A novel intranasal peptide vaccine inhibits non-small cell lung cancer with KRAS mutation.

KRAS mutations occur commonly in the lung and can lead to the development of non-small cell lung cancer (NSCLC). While the mutated KRAS protein is a neoantigen, it usually does not generate an effective anti-tumor immune response on mucosal/epithelial surfaces. Despite this, mutated KRAS remains a potential target for immunotherapy since immune targeting of this protein in animal models has been effective at eliminating tumor cells.

Delicate Hybrid Laponite-Cyclic Poly(ethylene glycol) Nanoparticles as a Potential Drug Delivery System.

The objective of the study was to explore the feasibility of a new drug delivery system using laponite (LAP) and cyclic poly(ethylene glycol) (cPEG). Variously shaped and flexible hybrid nanocrystals were made by both the covalent and physical attachment of chemically homogeneous cyclized PEG to laponite nanodisc plates. The size of the resulting, nearly spherical particles ranged from 1 to 1.

Dual acting oximes designed for therapeutic decontamination of reactive organophosphates catalytic inactivation and acetylcholinesterase reactivation.

A conventional approach in the therapeutic decontamination of reactive organophosphate (OP) relies on chemical OP degradation by oxime compounds. However, their efficacy is limited due to their lack of activity in the reactivation of acetylcholinesterase (AChE), the primary target of OP. Here, we describe a set of α-nucleophile oxime derivatives which are newly identified for such dual modes of action.

Dendrimer-based posaconazole nanoplatform for antifungal therapy.

We examined formulating a new antifungal agent, posaconazole (POS) and its derivatives, with different molecular vehicles. Several combinations of drug and carrier molecules were synthesized, and their antifungal activities were evaluated against . Posaconazole and four of its derivatives were conjugated to either generation 5 (G5) dendrimers or partially modified G5 dendrimers.

Caged Oxime Reactivators Designed for the Light Control of Acetylcholinesterase Reactivation.

Despite its promising role in the active control of biological functions by light, photocaging remains untested in acetylcholinesterase (AChE), a key enzyme in the cholinergic family. Here, we describe synthesis, photochemical properties and biochemical activities of two caged oxime compounds applied in the photocontrolled reactivation of the AChE inactivated by reactive organophosphate. Each of these consists of a photocleavable coumarin cage tethered to a known oxime reactivator for AChE that belongs in an either 2-(hydroxyimino)acetamide or pyridiniumaldoxime class.

Shielded α-Nucleophile Nanoreactor for Topical Decontamination of Reactive Organophosphate.

Here, we describe a nanoscale reactor strategy with a topical application in the therapeutic decontamination of reactive organophosphates (OPs) as chemical threat agents. It involves functionalization of poly(amidoamine) dendrimer through a combination of its partial PEG shielding and exhaustive conjugation with an OP-reactive α-nucleophile moiety at its peripheral branches. We prepared a 16-member library composed of two α-nucleophile classes (oxime, hydroxamic acid), each varying in its reactor valency (43-176 reactive units per nanoparticle), and linker framework for α-nucleophile tethering.

Spacer-Mediated Control of Coumarin Uncaging for Photocaged Thymidine.

Despite its importance in the design of photocaged molecules, less attention is focused on linker chemistry than the cage itself. Here, we describe unique uncaging properties displayed by two coumarin-caged thymidine compounds, each conjugated with () or without () an extended, self-immolative spacer. Photolysis of using long-wavelength UVA (365 nm) or visible (420, 455 nm) light led to the release of free thymidine along with the competitive generation of a thymidine-bearing recombination product.

Reactivity and mechanism of α-nucleophile scaffolds as catalytic organophosphate scavengers.

Despite their unique benefits imparted by their structure and reactivity, certain α-nucleophile molecules remain underexplored as chemical inactivators for the topical decontamination of reactive organophosphates (OPs). Here, we present a library of thirty α-nucleophile scaffolds, each designed with either a pyridinium aldoxime (PAM) or hydroxamic acid (HA) α-nucleophile core tethered to a polar or charged scaffold for optimized physicochemical properties and reactivity. These library compounds were screened for their abilities to catalyze the hydrolysis of a model OP, paraoxon (POX), in kinetic assays.

Hydrophilic scaffolds of oxime as the potent catalytic inactivator of reactive organophosphate.

Despite its efficacy as a skin decontaminant of reactive organophosphates (OP), Dekon 139-a potassium salt of 2,3-butanedione monooxime (DAM)-is associated with adverse events related to percutaneous absorption largely due to its small size and lipophilicity. In order to address this physicochemical issue, we synthesized and evaluated the activity of a focused library of 14 hydrophilic oxime compounds, each designed with either a DAM or monoisonitrosoacetone (MINA) oxime tethered to a polar or charged scaffold in order to optimize the size, hydrophilicity, and oxime acidity. High-throughput colorimetric assays were performed with paraoxon (POX) as a model OP to determine the kinetics of POX inactivation by these compounds under various pH and temperature conditions.

Measuring the Adhesion Forces for the Multivalent Binding of Vancomycin-Conjugated Dendrimer to Bacterial Cell-Wall Peptide.

Multivalent ligand-receptor interaction provides the fundamental basis for the hypothetical notion that high binding avidity relates to the strong force of adhesion. Despite its increasing importance in the design of targeted nanoconjugates, an understanding of the physical forces underlying the multivalent interaction remains a subject of urgent investigation. In this study, we designed three vancomycin (Van)-conjugated dendrimers G5(Van) ( n = mean valency = 0, 1, 4) for bacterial targeting with generation 5 (G5) poly(amidoamine) dendrimer as a multivalent scaffold and evaluated both their binding avidity and physical force of adhesion to a bacterial model surface by employing surface plasmon resonance (SPR) spectroscopy and atomic force microscopy.

Oritavancin Retains a High Affinity for a Vancomycin-Resistant Cell-Wall Precursor via Its Bivalent Motifs of Interaction.

Despite its potent antibacterial activities against drug-resistant Gram-positive pathogens, oritavancin remains partially understood with respect to its primary mode of hydrogen bond interaction with a cell-wall peptide regarding the role of its lipophilic 4'-chlorobiphenyl moiety. Here we report a surface plasmon resonance (SPR) study performed in two cell-wall model surfaces, each prepared by immobilization with a vancomycin-susceptible Lys-d-Ala-d-Ala or vancomycin-resistant Lys-d-Ala-d-Lac peptide. Analysis of binding kinetics performed on the peptide surface showed that oritavancin bound ∼100-1000-fold more tightly than vancomycin on each model surface.

Photocontrolled Release of Doxorubicin Conjugated through a Thioacetal Photocage in Folate-Targeted Nanodelivery Systems.

Despite their proven ability for precise and targeted release, nanoplatform systems for photocontrolled delivery often face formidable synthetic challenges, in part due to the paucity of advanced linker strategies. Here, we report on a novel linker strategy using a thioacetal ortho-nitrobenzaldehyde (TNB) cage, demonstrating its application for delivery of doxorubicin (Dox) in two nanoscale systems. This photocleavable linker, TNB(OH), which presents two identical arms, each terminated with a hydroxyl functionality, was prepared in a single step from 6-nitroveratraldehyde.

Control of an Unusual Photo-Claisen Rearrangement in Coumarin Caged Tamoxifen through an Extended Spacer.

The use of coumarin caged molecules has been well documented in numerous photocaging applications including for the spatiotemporal control of Cre-estrogen receptor (Cre-ERT2) recombinase activity. In this article, we report that 4-hydroxytamoxifen (4OHT) caged with coumarin via a conventional ether linkage led to an unexpected photo-Claisen rearrangement which significantly competed with the release of free 4OHT. The basis for this unwanted reaction appears to be related to the coumarin structure and its radical-based mechanism of uncaging, as it did not occur in ortho-nitrobenzyl (ONB) caged 4OHT that was otherwise linked in the same manner.

A Thioacetal Photocage Designed for Dual Release: Application in the Quantitation of Therapeutic Release by Synchronous Reporter Decaging.

Despite the immense potential of existing photocaging technology, its application is limited by the paucity of advanced caging tools. Here, we report on the design of a novel thioacetal ortho-nitrobenzaldehyde (TNB) dual arm photocage that enabled control of the simultaneous release of two payloads linked to a single TNB unit. By using this cage, which was prepared in a single step from commercial 6-nitroverataldehyde, three drug-fluorophore conjugates were synthesized: Taxol-TNB-fluorescein, Taxol-TNB-coumarin, and doxorubicin-TNB-coumarin, and long-wavelength UVA light-triggered release experiments demonstrated that dual payload release occurred with rapid decay kinetics for each conjugate.

Light-controlled active release of photocaged ciprofloxacin for lipopolysaccharide-targeted drug delivery using dendrimer conjugates.

We report an active delivery mechanism targeted specifically to Gram(-) bacteria based on the photochemical release of photocaged ciprofloxacin carried by a cell wall-targeted dendrimer nanoconjugate.

Mechanism of Cooperativity and Nonlinear Release Kinetics in Multivalent Dendrimer-Atropine Complexes.

Despite extensive studies on drug delivery using multivalent complexation systems, the biophysical basis for release kinetics remains poorly defined. The present study addresses this aspect involved in the complexation of a fifth generation poly(amidoamine) (PAMAM) dendrimer with atropine, an essential antidote used for treating organophosphate poisoning. First, we designed (1)H NMR titration studies for determining the molecular basis of the drug complexation with a glutarate-modified anionic dendrimer.

Modular Integration of Upconverting Nanocrystal-Dendrimer Composites for Folate Receptor-Specific NIR Imaging and Light-Triggered Drug Release.

Upconversion nanocrystals (UCNs) display near-infrared (NIR)-responsive photoluminescent properties for NIR imaging and drug delivery. The development of effective strategies for UCN integration with other complementary nanostructures for targeting and drug conjugation is highly desirable. This study reports on a core/shell-based theranostic system designed by UCN integration with a folate (FA)-conjugated dendrimer for tumor targeting and with photocaged doxorubicin as a cytotoxic agent.

Force spectroscopy of multivalent binding of riboflavin-conjugated dendrimers to riboflavin binding protein.

Putative riboflavin receptors are considered as biomarkers due to their overexpression in breast and prostate cancers. Hence, these receptors can be potentially exploited for use in targeted drug delivery systems where dendrimer nanoparticles with multivalent ligand attachments can lead to greater specificity in cellular interactions. In this study, the single molecule force spectroscopy technique was used to assess the physical strength of multivalent interactions by employing a riboflavin (RF)-conjugated generation 5 PAMAM dendrimer G5(RF)n nanoparticle.

A lipopolysaccharide binding heteromultivalent dendrimer nanoplatform for Gram negative cell targeting.

We report on the practicality of a heteromultivalent design strategy for a nanoplatform that targets lipopolysaccharide molecules (LPS) present on the surface of Gram-negative bacteria. This design is based on the conjugation of a poly(amido amine) (PAMAM) dendrimer with two types of ligands, each having distinct affinities: (i) polymyxin B (PMB) as a primary high affinity ligand; (ii) a PMB-mimicking dendritic branch as an auxiliary low affinity ligand. Co-conjugation of these two ligands maximizes the efficiency of the primary ligand even when the primary ligand is present at a low valency on the nanoplatform (mean n≈ 1).

4-Hydroxytamoxifen probes for light-dependent spatiotemporal control of Cre-ER mediated reporter gene expression.

The tamoxifen inducible Cre-ER/loxP system provides tissue specific temporal control of gene recombination events, and can be used to induce expression of reporter genes (e.g. GFP, LacZ) for lineage tracing studies.

Multivalent dendrimer vectors with DNA intercalation motifs for gene delivery.

Poly(amido amine) (PAMAM) dendrimers constitute an important class of nonviral, cationic vectors in gene delivery. Here we report on a new concept for dendrimer vector design based on the incorporation of dual binding motifs: DNA intercalation, and receptor recognition for targeted delivery. We prepared a series of dendrimer conjugates derived from a fifth generation (G5) PAMAM dendrimer, each conjugated with multiple folate (FA) or riboflavin (RF) ligands for cell receptor targeting, and with 3,8-diamino-6-phenylphenanthridinium ("DAPP")-derived ligands for anchoring a DNA payload.

Design considerations for PAMAM dendrimer therapeutics.

We have previously shown that methotrexate (MTX) conjugated to a cancer-specific poly amido amine (PAMAM) dendrimer has a higher therapeutic index than MTX alone. Unfortunately, these therapeutics have been difficult to advance because of the complicated syntheses and an incomplete understanding of the dendrimer properties. We wished to address these obstacles by using copper-free click chemistry to functionalize the dendrimer scaffolds and to exploring the effects of two dendrimer properties (the targeting ligand and drug linkage) on cytotoxicity.

The facile synthesis of multifunctional PAMAM dendrimer conjugates through copper-free click chemistry.

The facile conjugation of three azido modified functionalities, namely a therapeutic drug (methotrexate), a targeting moiety (folic acid), and an imaging agent (fluorescein) with a G5 PAMAM dendrimer scaffold with cyclooctyne molecules at the surface through copper-free click chemistry is reported. Mono-, di-, and tri-functional PAMAM dendrimer conjugates can be obtained via combinatorial mixing of different azido modified functionalities simultaneously or sequentially with the dendrimer platform. Preliminary flow cytometry results indicate that the folic acid targeted nanoparticles are efficiently binding with KB cells.

Copper-free click conjugation of methotrexate to a PAMAM dendrimer platform.

The synthesis of a generation 5 (G5) poly(amidoamine) (PAMAM) dendrimer platform having cyclooctyne ligands that were subsequently be used for a copper-free Huisgen 1,3-dipolar cycloaddition (click reaction) with azido modified methotrexate is described. The G5 PAMAM dendrimer was first partially (70%) acetylated and then coupled with 20 cyclooctyne ligands through amide bonds. The remaining primary amine groups on the dendrimer surface were neutralized by acetylation.

The synthesis of a c(RGDyK) targeted SN38 prodrug with an indolequinone structure for bioreductive drug release.

Preparation of a novel c(RGDyK) targeted SN38 prodrug incorporating an indolequinone structure for bioreductively triggered drug release is described. This design yields a prodrug that targets surface molecules on tumor cells (alpha(v)beta(3) integrins) and releases drug under bioreductive conditions. There are three moieties in the prodrug design, namely a therapeutic drug SN38, an indolequinone structure serving as a drug releasing trigger, and an alpha(v)beta(3) integrin targeting peptide c(RGDyK).