Nurr1:RXRα heterodimer activation as monotherapy for Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic (DAergic) neurons in the substantia nigra and the gradual depletion of dopamine (DA). Current treatments replenish the DA deficit and improve symptoms but induce dyskinesias over time, and neuroprotective therapies are nonexistent. Here we report that Nuclear receptor-related 1 (Nurr1):Retinoid X receptor α (RXRα) activation has a double therapeutic potential for PD, offering both neuroprotective and symptomatic improvement. We designed BRF110, a unique in vivo active Nurr1:RXRα-selective lead molecule, which prevents DAergic neuron demise and striatal DAergic denervation in vivo against PD-causing toxins in a Nurr1-dependent manner. BRF110 also protects against PD-related genetic mutations in patient induced pluripotent stem cell (iPSC)-derived DAergic neurons and a genetic mouse PD model. Remarkably, besides neuroprotection, BRF110 up-regulates tyrosine hydroxylase (TH), aromatic l-amino acid decarboxylase (AADC), and GTP cyclohydrolase I (GCH1) transcription; increases striatal DA in vivo; and has symptomatic efficacy in two postneurodegeneration PD models, without inducing dyskinesias on chronic daily treatment. The combined neuroprotective and symptomatic effects of BRF110 identify Nurr1:RXRα activation as a potential monotherapeutic approach for PD.

Gemcitabine Based Peptide Conjugate with Improved Metabolic Properties and Dual Mode of Efficacy.

Gemcitabine is a clinically established anticancer agent potent in various solid tumors but limited by its rapid metabolic inactivation and off-target toxicity. We have previously generated a metabolically superior to gemcitabine molecule (GSG) by conjugating gemcitabine to a gonadotropin releasing hormone receptor (GnRH-R) ligand peptide and showed that GSG was efficacious in a castration resistant prostate cancer (CRPC) animal model. The current article provides an in-depth metabolic and mechanistic study of GSG, coupled with toxicity assays that strengthen the potential role of GSG in the clinic. LC-MS/MS based approaches were employed to delineate the metabolism of GSG, its mechanistic cellular uptake, and release of gemcitabine and to quantitate the intracellular levels of gemcitabine and its metabolites (active dFdCTP and inactive dFdU) resulting from GSG. The GnRH-R agonistic potential of GSG was investigated by quantifying the testosterone levels in animals dosed daily with GSG, while an in vitro colony forming assay together with in vivo whole blood measurements were performed to elucidate the hematotoxicity profile of GSG. Stability showed that the major metabolite of GSG is a more stable nonapeptide that could prolong gemcitabine's bioavailability. GSG acted as a prodrug and offered a metabolic advantage compared to gemcitabine by generating higher and steadier levels of dFdCTP/dFdU ratio, while intracellular release of gemcitabine from GSG in DU145 CRPC cells depended on nucleoside transporters. Daily administrations in mice showed that GSG is a potent GnRH-R agonist that can also cause testosterone ablation without any observed hematotoxicity. In summary, GSG could offer a powerful and unique pharmacological approach to prostate cancer treatment: a single nontoxic molecule that can be used to reach the tumor site selectively with superior to gemcitabine metabolism, biodistribution, and safety while also agonistically ablating testosterone levels.

GnRH-Gemcitabine conjugates for the treatment of androgen-independent prostate cancer: pharmacokinetic enhancements combined with targeted drug delivery.

Gemcitabine, a drug with established efficacy against a number of solid tumors, has therapeutic limitations due to its rapid metabolic inactivation. The aim of this study was the development of an innovative strategy to produce a metabolically stable analogue of gemcitabine that could also be selectively delivered to prostate cancer (CaP) cells based on cell surface expression of the Gonadotropin Releasing Hormone-Receptor (GnRH-R). The synthesis and evaluation of conjugated molecules, consisting of gemcitabine linked to a GnRH agonist, is presented along with results in androgen-independent prostate cancer models. NMR and ligand binding assays were employed to verify conservation of microenvironments responsible for binding of novel GnRH-gemcitabine conjugates to the GnRH-R. In vitro cytotoxicity, cellular uptake, and metabolite formation of the conjugates were examined in CaP cell lines. Selected conjugates were efficacious in the in vitro assays with one of them, namely, GSG, displaying high antiproliferative activity in CaP cell lines along with significant metabolic and pharmacokinetic advantages in comparison to gemcitabine. Finally, treatment of GnRH-R positive xenografted mice with GSG showed a significant advantage in tumor growth inhibition when compared to gemcitabine.

Combination of Doxorubicin and Antiangiogenic Agents in Drug-Eluting Beads: In Vitro Loading and Release Dynamics in View of a Novel Therapeutic Approach for Hepatocellular Carcinoma.

PURPOSE: Antiangiogenic agents have been used for many years as a first-line systemic treatment for advanced HCC. Embolization with cytostatic drugs on the other hand is the first-line treatment for intermediate HCC. The two types of drugs have not been combined for intraarterial delivery yet. The loading and release dynamics and the in vitro effect of their combination are tested in this experimental study. MATERIALS AND METHODS: Drug-eluting beads were loaded with doxorubicin, sunitinib and sunitinib analogue piperazine (SAP) alone and with their combinations. Diameter change, loading, release, and effect in cellular proliferation were assessed. RESULTS: The average microsphere diameter after loading was 473.7 µm (µm) for Doxorubicin, 388.4 µm for Sunitinib, 515.5 µm for SAP, 414.8 µm for the combination Doxorubicin/Sunitinib and 468.8 µm for the combination Doxorubicin /SAP. Drug release in 0.9% NaCl was 10% for Doxorubicin, 49% for Sunitinib, 25% for SAP, 20%/18% for the combination Doxorubicin/Sunitinib, and 18%/23% for the combination Doxorubicin/SAP whereas in human plasma it was 56%, 27%, 13%, 76%/63% and 62%/15%, respectively. The mean concentration of Doxorubicin that led to inhibition of 50% of cellular proliferation in an HCC Huh7 cell line was 163.1 nM (nM), for Sunitinib 10.3 micromolar (µΜ), for SAP 16.7 µΜ, for Doxorubicin/Sunitinib 222.4 nM and for Doxorubicin/SAP 275 nM. CONCLUSIONS: Doxorubicin may be combined with antiangiogenic drugs with satisfactory in vitro loading and release outcomes and effect on cellular lines.

Transarterial embolization with sorafenib in animal livers: a pharmacokinetics study.

PURPOSE: To assess the safety and feasibility of the targeted delivery of the antiangiogenic drug sorafenib to the liver using transarterial chemoembolization methodology as a novel approach to hepatocellular carcinoma (HCC) therapy. MATERIALS AND METHODS: Seven healthy New Zealand white rabbits were used in the study. After placement of a catheter in the common hepatic artery, six rabbits were treated with chemoembolization of sorafenib in iodized oil (Lipiodol) (sorafenib dose 0.1 mg/kg), and one rabbit received Lipiodol only. Liquid chromatography tandem mass spectrometry was used to measure the concentration of sorafenib in the peripheral blood and liver tissue 24 hours and 72 hours after treatment. Histochemical staining of the liver sections and biochemical measurements were performed. RESULTS: The administration of sorafenib in Lipiodol emulsions by transarterial chemoembolization resulted in sorafenib concentrations of 794 ng/g ± 240 and 64 ng/g ± 15 in the liver tissue 24 hours and 72 hours after treatment. The average liver-to-serum ratios 24 hours and 72 hours after treatment were approximately 14 and 22. The histochemical staining of the liver tissue sections and aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase and total bilirubin concentrations indicated no significant liver damage. CONCLUSIONS: Transarterial chemoembolization with sorafenib in Lipiodol is an effective methodology for the localized delivery of this drug to the liver and has possible practical implications in therapeutic interventions for the treatment of hepatocellular carcinoma.

Targeting oncogenic protein-protein interactions by diversity oriented synthesis and combinatorial chemistry approaches.

We are currently witnessing a decline in the development of efficient new anticancer drugs, despite the salient efforts made on all fronts of cancer drug discovery. This trend presumably relates to the substantial heterogeneity and the inherent biological complexity of cancer, which hinder drug development success. Protein-protein interactions (PPIs) are key players in numerous cellular processes and aberrant interruption of this complex network provides a basis for various disease states, including cancer. Thus, it is now believed that cancer drug discovery, in addition to the design of single-targeted bioactive compounds, should also incorporate diversity-oriented synthesis (DOS) and other combinatorial strategies in order to exploit the ability of multi-functional scaffolds to modulate multiple protein-protein interactions (biological hubs). Throughout the review, we highlight the chemistry driven approaches to access diversity space for the discovery of small molecules that disrupt oncogenic PPIs, namely the p53-Mdm2, Bcl-2/Bcl-xL-BH3, Myc-Max, and p53-Mdmx/Mdm2 interactions.

Cyanobacterial cyclopeptides as lead compounds to novel targeted cancer drugs.

Cyanobacterial cyclopeptides, including microcystins and nodularins, are considered a health hazard to humans due to the possible toxic effects of high consumption. From a pharmacological standpoint, microcystins are stable hydrophilic cyclic heptapeptides with a potential to cause cellular damage following uptake via organic anion-transporting polypeptides (OATP). Their intracellular biological effects involve inhibition of catalytic subunits of protein phosphatase 1 (PP1) and PP2, glutathione depletion and generation of reactive oxygen species (ROS). Interestingly, certain OATPs are prominently expressed in cancers as compared to normal tissues, qualifying MC as potential candidates for cancer drug development. In the era of targeted cancer therapy, cyanotoxins comprise a rich source of natural cytotoxic compounds with a potential to target cancers expressing specific uptake transporters. Moreover, their structure offers opportunities for combinatorial engineering to enhance the therapeutic index and resolve organ-specific toxicity issues. In this article, we revisit cyanobacterial cyclopeptides as potential novel targets for anticancer drugs by summarizing existing biomedical evidence, presenting structure-activity data and discussing developmental perspectives.

One-pot surfactant-free modulation of size and functional group distribution in thermoresponsive microgels.

Control over the size and functional group distribution of soft responsive hydrogel particles is essential for applications such as drug delivery, catalysis and chemical sensing. Traditionally, targeted functional group distributions are achieved with semi-batch techniques which require specialized equipment, while the preparation of size-tailored particles typically involves the use of surfactants. Herein, we present a simple and robust surfactant-free method for the modulation of size and carboxylic acid functional group distribution in poly(N-isopropylacrylamide) thermoresponsive microgels, employing reaction pH as the single experimental parameter. The varying distributions of carboxylic acid residues arise due to differences in kinetic reactivity, which are a function of the degree of dissociation of methacrylic acid, and thus of reaction pH. Incorporated charged residues induce a surfactant-like action during the particle nucleation stage, and impact the final particle size. Characterization with dynamic light scattering, and electron microscopy consistently supports the pH-tailored morphology of the microgels. A mathematical model which accounts for particle deformation on the imaging substrate also shows excellent agreement with the experimental results.

Targeting of the breast cancer microenvironment with a potent and linkable oxindole based antiangiogenic small molecule.

The clinical efficacy of antiangiogenic small molecules (e.g., sunitinib) in breast carcinoma has largely failed with substantial off-target toxicity. We rationally designed and evaluated preclinically a novel sunitinib analogue, SAP, with favourable pharmacological properties and the ability to be readily conjugated to a targeting peptide or antibody for active tumour targeting.SAP was evaluated in silico and in vitro in order to verify target engagement (e.g., VEGFR2). Pharmacokinetic and biodistribution parameters were determined in mice using LC-MS/MS. SAP efficacy was tested in two breast cancer xenograft and two syngeneic animal models and pharmacodynamic evaluation was accomplished using phosphokinase assays and immunohistochemistry. Cardiac and blood toxicity of SAP were also monitored.SAP retained the antiangiogenic and cytotoxic properties of the parental molecule with an increased blood exposure and tumor accumulation compared to sunitinib. SAP proved efficacious in all animal models. Tumors from SAP treated animals had significantly decreased Ki-67 and CD31 markers and reduced levels of phosphorylated AKT, ERK and S6 compared to vehicle treated animals. In mice dosed with SAP there was negligible hematotoxicity, while cardiac function measurements showed a reduction in the percentage left ventricular fractional shortening compared to vehicle treated animals.In conclusion, SAP is a novel rationally designed conjugatable small antiangiogenic molecule, efficacious in preclinical models of breast cancer.

Peptide-Drug Conjugate GnRH-Sunitinib Targets Angiogenesis Selectively at the Site of Action to Inhibit Tumor Growth.

The potential to heighten the efficacy of antiangiogenic agents was explored in this study based on active targeting of tumor cells overexpressing the gonadotropin-releasing hormone receptor (GnRH-R). The rational design pursued focused on five analogues of a clinically established antiangiogenic compound (sunitinib), from which a lead candidate (SAN1) was conjugated to the targeting peptide [d-Lys(6)]-GnRH, generating SAN1GSC. Conjugation of SAN1 did not disrupt any of its antiangiogenic or cytotoxic properties in GnRH-R-expressing prostate and breast tumor cells. Daily SAN1GSC treatments in mouse xenograft models of castration-resistant prostate cancer resulted in significant tumor growth delay compared with equimolar SAN1 or sunitinib alone. This efficacy correlated with inhibited phosphorylation of AKT and S6, together with reduced Ki-67 and CD31 expression. The superior efficacy of the peptide-drug conjugate was also attributed to the finding that higher amounts of SAN1 were delivered to the tumor site (∼4-fold) following dosing of SAN1GSC compared with equimolar amounts of nonconjugated SAN1. Importantly, treatment with SAN1GSC was associated with minimal hematotoxicity and cardiotoxicity based on measurements of the left ventricular systolic function in treated mice. Our results offer preclinical proof-of-concept for SAN1GSC as a novel molecule that selectively reaches the tumor site and downregulates angiogenesis with negligible cardiotoxicity, thus encouraging its further clinical development and evaluation.

Microcystin LR Shows Cytotoxic Activity Against Pancreatic Cancer Cells Expressing the Membrane OATP1B1 and OATP1B3 Transporters.

Microcystin-LR (MC-LR) is a cyanobacterial cyclopeptide, known for its unique ability to cause acute liver injury. Its cellular uptake is facilitated by specific transmembrane organic anion-transporting polypeptides (OATPs) specifically OATP1B1 and 1B3. The objective of the present study was to investigate the expression of OATPs 1A2, 1B1 and 1B3 in pancreatic cancer cell lines BxPC-3 and MIA PACA-2 and assess their role in MC-LR-mediated cytotoxicity by using the novel xCELLigence system and flow cytometry. OATP1B1 and 1B3 were found to be expressed in both cell lines at both the mRNA and protein levels. The cytotoxic effects of MC-LR were proportionally related to the expression of these transporters. Moreover the cytotoxic potency of MC-LR was found superior to gemcitabine. Based on the expression of the organic anion transporting polypeptides 1B1 and 1B3 in pancreatic carcinoma tissue and cell lines and the potent cytotoxicity induced by MC-LR in vitro, we propose that this molecule could be held as structural basis for the development of novel targeted-compounds against pancreatic cancer.

Diversity oriented synthesis of a vinblastine-templated library of 7-aryl-octahydroazonino[5,4-b]indoles via a three-component reaction.

A vinblastine-templated library of 7-aryl-octahydroazonino[5,4-b]indoles was prepared by a three-component reaction from indolizino[8,7-b]indoles, chloroformates, and activated arenes via a chloroformate mediated fragmentation of the indolizinoindole nucleus followed by insertion of an activated arene. In addition to N3-carbamoyl-7-aryl-octahydroazonino[5,4-b]indoles prepared in one step, a wide range of N3-substituted substrates were synthesized in one pot via the derivatization of a versatile N3-H-azonino[5,4-b]indole intermediate generated in situ by application of the same strategy. A subset of 308 compounds out of a virtual library of 3216, representing 13 different chemotypes, was prepared by high throughput solution-phase synthesis and subsequently purified by mass-triggered high performance liquid chromatography (HPLC). A total of 188 compounds with a minimum purity of 80% by UV214 nm and 85% by evaporative light scattering detection (ELSD) was isolated for primary screening.

Lipophilic caffeic acid derivatives protect cells against H2O2-Induced DNA damage by chelating intracellular labile iron.

Naturally occurring cinnamic acid derivatives are ubiquitously distributed in the plant kingdom, and it has been proposed that their consumption contributes to the maintenance of human health. However, the molecular mechanisms underlying their health keeping effects remain unknown. In the present investigation, we evaluated the capacity of several cinnamic acid derivatives (trans-cinnamic, p-coumaric, caffeic and ferulic acids, as well as caffeic acid-methyl and -propyl esters) to protect cells from oxidative stress-induced DNA damage. It was observed that effective protection was based on the ability of each compound to (i) reach the intracellular space and (ii) chelate intracellular "labile" iron. These results support the notion that numerous lipophilic iron chelating compounds, present abundantly in plant-derived diet components, may protect cells in conditions of oxidative stress and in this way be important contributors toward maintenance of human health.

Grafting of imidazolium based ionic liquid on the pore surface of nanoporous materials--study of physicochemical and thermodynamic properties.

Supported ionic liquid phase (SILP) systems were prepared by immobilizing a methylimidazolium cation based ionic liquid onto the pore surface of two types of support, MCM-41 and Vycor. The "grafting to" method was applied, involving (3-chloropropyl)-trialkoxysilane anchoring on the supports' silanol groups, followed by treatment with 1-methylimidazole and ion exchange with PF(6)(-). Optimum surface pretreatment procedures and reaction conditions for enhanced ionic liquid (IL) loading were properly defined and applied for all modifications. A study on the effect of different pore sizes on the physical state of the grafted 1-(silylpropyl)-3-methylimidazolium-hexafluorophosphate ([spmim][PF(6)(-)]) was also conducted. The [spmim][PF(6)(-)] crystallinity under extreme confinement in the pores was investigated by modulated differential scanning calorimetry (DSC) and X-ray diffraction (XRD) and was further related to the capacity of the developed SILP to preferentially adsorb CO(2) over CO. For this purpose, CO(2) and CO absorption measurements of the bulk ionic liquid [bmim][PF(6)(-)] and the synthesized alkoxysilyl-IL were initially performed at several temperatures. The results showed an enhancement of the bulk IL performance to preferentially adsorb CO(2) at 273 K. The DSC analysis of the SILPs revealed transition of the melting point of the grafted alkoxysilyl-IL to higher temperatures when the support pore size was below 4 nm. The 2.3 nm MCM-41 SILP system exhibited infinite CO(2)/CO separation capacity at temperatures below and above the melting point of the bulk IL phase, adsorbing in parallel significant amounts of CO(2) in a reversible manner. These properties make the developed material an excellent candidate for CO(2)/CO separation with pressure swing adsorption (PSA) techniques.

Enantioselective synthesis of (-)-dihydrocodeinone: a short formal synthesis of (-)-morphine.

[reaction: see text] The radical cyclization approach to the morphine alkaloids has been applied in an asymmetric synthesis of (-)-dihydrocodeinone. A chiral cyclohexenol (R-32), from the CBS reduction of the enone, is the source of chirality. The first key step, tandem closure in which stereochemistry is controlled by geometric constraints, (-)-15b --> (+)-16, was followed by an unprecedented reductive hydroamination, completing the synthesis of (-)-dihydroisocodeine ((-)-17) in 13 steps from commercially available materials.

Strategies for the synthesis of novel indole alkaloid-based screening libraries for drug discovery.

A series of diverse indole-based chemotypes were synthesized from beta-tetrahydrocarboline (beta-THC) scaffolds prepared from commercially and readily available tryptamines and alpha-ketoesters. Diversity can be generated within these chemotypes through the following strategies: (a) appendage of substituents to the beta-THC scaffold, prepared in situ or as a template, through further elaboration and (b) skeletal modifications to the beta-THC scaffold via ring forming or ring breaking reactions. The strategies described here are amenable to high throughput solution-phase parallel synthesis, providing access to novel indole-based screening libraries for drug discovery.