A TLR7 Agonist Conjugated to a Nanofibrous Peptide Hydrogel as a Potent Vaccine Adjuvant.

Toll-like receptors (TLRs) recognize pathogen- and damage-associated molecular patterns and, in turn, trigger the release of cytokines and other immunostimulatory molecules. As a result, TLR agonists are increasingly being investigated as vaccine adjuvants, though many of these agonists are small molecules that quickly diffuse away from the vaccination site, limiting their co-localization with antigens and, thus, their effect. Here, the small-molecule TLR7 agonist 1V209 is conjugated to a positively-charged multidomain peptide (MDP) hydrogel, K 2 , which was previously shown to act as an adjuvant promoting humoral immunity. Mixing the 1V209-conjugated K 2 50:50 with the unfunctionalized K 2 produces hydrogels that retain the shear-thinning and self-healing physical properties of the original MDP, while improving the solubility of 1V209 more than 200-fold compared to the unconjugated molecule. When co-delivered with ovalbumin as a model antigen, 1V209-functionalized K 2 produces antigen-specific IgG titers that were statistically similar to alum, the gold standard adjuvant, and a significantly lower ratio of Th2-associated IgG1 to Th1-associated IgG2a than alum, suggesting a more balanced Th1 and Th2 response. Together, these results suggest that K 2 MDP hydrogels functionalized with 1V209 are a promising adjuvant for vaccines against infectious diseases, especially those benefiting from a combined Th1 and Th2 immune response. Table of Contents: Activation of toll-like receptors (TLRs) stimulates a signaling cascade to induce an immune response. A TLR7 agonist was conjugated to an injectable peptide hydrogel, which was then used to deliver a model vaccine antigen. This platform produced antibody titers similar to the gold standard adjuvant alum and demonstrated an improved balance between Th1- and Th2-mediated immunity over alum.

Rifampin- and Silymarin-Mediated Pharmacokinetic Interactions of Exogenous and Endogenous Substrates in a Transgenic OATP1B Mouse Model.

Organic anion-transporting polypeptides (OATP) 1B1 and OATP1B3, encoded by the SLCO gene family of the solute carrier superfamily, are involved in the disposition of many exogenous and endogenous compounds. Preclinical rodent models help assess risks of pharmacokinetic interactions, but interspecies differences in transporter orthologs and expression limit direct clinical translation. An OATP1B transgenic mouse model comprising a rodent Slco1a/1b gene cluster knockout and human SLCO1B1 and SLCO1B3 gene insertions provides a potential physiologically relevant preclinical tool to predict pharmacokinetic interactions. Pharmacokinetics of exogenous probe substrates, pitavastatin and pravastatin, and endogenous OATP1B biomarkers, coproporphyrin-I and coproporphyrin-III, were determined in the presence and absence of known OATP/Oatp inhibitors, rifampin or silymarin (an extract of milk thistle [Silybum marianum]), in wild-type FVB mice and humanized OATP1B mice. Rifampin increased exposure of pitavastatin (4.6- and 2.8-fold), pravastatin (3.6- and 2.2-fold), and coproporphyrin-III (1.6- and 2.1-fold) in FVB and OATP1B mice, respectively, but increased coproporphyrin-I AUC0-24h only (1.8-fold) in the OATP1B mice. Silymarin did not significantly affect substrate AUC, likely because the silymarin flavonolignan concentrations were at or below their reported IC50 values for the relevant OATPs/Oatps. Silymarin increased the Cmax of pitavastatin 2.7-fold and pravastatin 1.9-fold in the OATP1B mice. The data of the OATP1B mice were similar to those of the pitavastatin and pravastatin clinical data; however, the FVB mice data more closely recapitulated pitavastatin clinical data than the data of the OATP1B mice, suggesting that the OATP1B mice are a reasonable, though costly, preclinical strain for predicting pharmacokinetic interactions when doses are optimized to achieve clinically relevant plasma concentrations.

Pharmacokinetic Effects of Different Models of Nonalcoholic Fatty Liver Disease in Transgenic Humanized OATP1B Mice.

Organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 (collectively, OATP1B) transporters encoded by the solute carrier organic anion transporter (SLCO) genes mediate uptake of multiple pharmaceutical compounds. Nonalcoholic steatohepatitis (NASH), a severe form of nonalcoholic fatty liver disease (NAFLD), decreases OATP1B abundance. This research characterized the pathologic and pharmacokinetics effects of three diet- and one chemical-induced NAFLD model in male and female humanized OATP1B mice, which comprises knock-out of rodent Oatp orthologs and insertion of human SLCO1B1 and SLCO1B3. Histopathology scoring demonstrated elevated steatosis and inflammation scores for all NAFLD-treatment groups. Female mice had minor changes in SLCO1B1 expression in two of the four NAFLD treatment groups, and pitavastatin (PIT) area under the concentration-time curve (AUC) increased in female mice in only one of the diet-induced models. OATP1B3 expression decreased in male and female mice in the chemical-induced NAFLD model, with a coinciding increase in PIT AUC, indicating the chemical-induced model may better replicate changes in OATP1B3 expression and OATP substrate disposition observed in NASH patients. This research also tested a reported multifactorial pharmacokinetic interaction between NAFLD and silymarin, an extract from milk thistle seeds with notable OATP-inhibitory effects. Males showed no change in PIT AUC, whereas female PIT AUC increased 1.55-fold from the diet alone and the 1.88-fold from the combination of diet with silymarin, suggesting that female mice are more sensitive to pharmacokinetic changes than male mice. Overall, the humanized OATP1B model should be used with caution for modeling NAFLD and multifactorial pharmacokinetic interactions. SIGNIFICANCE STATEMENT: Advanced stages of NAFLD cause decreased hepatic OATP1B abundance and increase systemic exposure to OATP substrates in human patients. The humanized OATP1B mouse strain may provide a clinically relevant model to recapitulate these observations and predict pharmacokinetic interactions in NAFLD. This research characterized three diet-induced and one drug-induced NAFLD model in a humanized OATP1B mouse model. Additionally, a multifactorial pharmacokinetic interaction was observed between silymarin and NAFLD.

Semisynthesis, Characterization, and Biological Evaluation of Fluorinated Analogues of the Spirobisnaphthalene, Diepoxin-η.

Diepoxin-η (1) is a cytotoxic fungal metabolite belonging to the spirobisnaphthalene structural class. In this study, four mono fluorinated analogues (2-5) of diepoxin-η (1) were semisynthesized in a single-step by selectively fluorinating the naphthalene moiety with Selectfluor. The structures of 2-5 were elucidated using a set of spectroscopic and spectrometric techniques and were further confirmed by means of TDDFT-ECD and isotropic shielding tensors calculations. Compounds 2-5 showed equipotent cytotoxic activity to 1 when tested against OVCAR3 (ovarian) and MDA-MB-435 (melanoma) cancer cell lines with IC50 values that range from 5.7-8.2 µM.

Green Tea Catechins Decrease Solubility of Raloxifene In Vitro and Its Systemic Exposure in Mice.

PURPOSE: Green tea is a widely consumed beverage. A recent clinical study reported green tea decreased systemic exposure of raloxifene and its glucuronide metabolites by 34-43%. However, the underlying mechanism(s) remains unknown. This study investigated a change in raloxifene's solubility as the responsible mechanism. METHODS: The effects of green tea extract, (-)-epigallocatechin gallate (EGCG), and (-)-epigallocatechin (EGC) on raloxifene's solubility were assessed in fasted state simulated intestinal fluids (FaSSIF) and fed state simulated intestinal fluids (FeSSIF). EGCG and EGC represent green tea's main bioactive constituents, flavan-3-gallate and flavan-3-ol catechins respectively, and the tested concentrations (mM) match the µg/mg of each compound in the extract. Our mouse study (n = 5/time point) evaluated the effect of green tea extract and EGCG on the systemic exposure of raloxifene. RESULTS: EGCG (1 mM) and EGC (1.27 mM) decreased raloxifene's solubility in FaSSIF by 78% and 13%, respectively. Micelle size in FaSSIF increased with increasing EGCG concentrations (> 1000% at 1 mM), whereas EGC (1.27 mM) did not change micelle size. We observed 3.4-fold higher raloxifene solubility in FeSSIF compared to FaSSIF, and neither green tea extract nor EGCG significantly affected raloxifene solubility or micelle size in FeSSIF. The mice study showed that green tea extract significantly decreased raloxifene Cmax by 44%, whereas EGCG had no effect. Green tea extract and EGCG did not affect the AUC0-24 h of raloxifene or the metabolite-to-parent AUC ratio. CONCLUSIONS: This study demonstrated flavan-3-gallate catechins may decrease solubility of poorly water-soluble drugs such as raloxifene, particularly in the fasted state.

Goldenseal-Mediated Inhibition of Intestinal Uptake Transporters Decreases Metformin Systemic Exposure in Mice.

Goldenseal is a perennial plant native to eastern North America. A recent clinical study reported goldenseal decreased metformin Cmax and area under the blood concentration versus time curve (AUC) by 27% and 23%, respectively, but half-life and renal clearance were unchanged. These observations suggested goldenseal altered processes involved in metformin absorption. The underlying mechanism(s) remain(s) unknown. One mechanism for the decreased metformin systemic exposure is inhibition by goldenseal of intestinal uptake transporters involved in metformin absorption. Goldenseal extract and three goldenseal alkaloids (berberine, (-)-ß-hydrastine, hydrastinine) were tested as inhibitors of organic cation transporter (OCT) 3, plasma membrane monoamine transporter (PMAT), and thiamine transporter (THTR) 2 using human embryonic kidney 293 cells overexpressing each transporter. The goldenseal extract, normalized to berberine content, was the strongest inhibitor of each transporter (IC50: 4.9, 13.1, and 5.8 µM for OCT3, PMAT, and THTR2, respectively). A pharmacokinetic study in mice compared the effects of berberine, (-)-ß-hydrastine, goldenseal extract, and imatinib (OCT inhibitor) on orally administered metformin. Goldenseal extract and imatinib significantly decreased metformin Cmax by 31% and 25%, respectively, and had no effect on half-life. Berberine and (-)-ß-hydrastine had no effect on metformin pharmacokinetics, indicating neither alkaloid alone precipitated the interaction in vivo. A follow-up murine study involving intravenous metformin and oral inhibitors examined the contributions of basolateral enteric/hepatic uptake transporters to the goldenseal-metformin interaction. Goldenseal extract and imatinib had no effect on metformin AUC and half-life, suggesting lack of inhibition of basolateral enteric/hepatic uptake transporters. Results may have implications for patients taking goldenseal with drugs that are substrates for OCT3 and THTR2. SIGNIFICANCE STATEMENT: Goldenseal is used to self-treat respiratory infections and digestive disorders. We investigated potential mechanisms for the clinical pharmacokinetic interaction observed between goldenseal and metformin, specifically inhibition by goldenseal of intestinal uptake transporters (OCT3, PMAT, THTR2) involved in metformin absorption. Goldenseal extract inhibited all three transporters in vitro and decreased metformin systemic exposure in mice. These data may have broader implications for patients co-consuming goldenseal with other drugs that are substrates for these transporters.

Evaluating the Antioxidant Properties of the Ancient-Crop Tef (Eragrostis tef) Grain Extracts in THP-1 Monocytes.

Tef (Eragrostis tef) is an orphan crop that is widely grown in East Africa, primarily in Ethiopia as a staple crop. It is becoming popular in the Western world owing to its nutritious and gluten-free grains and the forage quality of its biomass. Tef is also considered to have a high antioxidant capacity based on cell-free studies. However, the antioxidant activity of tef has never been validated using a physiologically relevant cell model. The purpose of this study was to investigate the antioxidant capacity of tef grain extracts using a mammalian cell model. We hypothesized that the tef grain extracts are capable of modulating the cellular antioxidant response via the modulation of glutathione (GSH) biosynthetic pathways. Therefore, we evaluated the antioxidant activity of purified tef grain extracts in the human acute monocytic leukemia (THP-1) cell line. Our findings revealed that the organic fraction of grain extracts increased the cellular GSH level, which was more evident for brown-colored tef than the ivory variety. Moreover, a brown-tef fraction increased the expressions of GSH-pathway genes, including γ-glutamate cysteine ligase catalytic (GCLC) and modifier (GCLM) subunits and glutathione reductase (GR), an enzyme that plays a key role in GSH biosynthesis, suggesting that tef extracts may modulate GSH metabolism. Several compounds were uniquely identified via mass spectrometry (MS) in GSH-modulating brown-tef samples, including 4-oxo-ß-apo-13-carotenone, γ-linolenic acid (methyl ester), 4,4'-(2,3-dimethyl-1,4-butanediyl)bis-phenol (also referred to as 8,8'-lignan-4,4'-diol), and (3ß)-3-[[2-[4-(Acetylamino)phenoxy]acetyl]oxy]olean-12-en-28-oic acid. Tef possesses antioxidant activity due to the presence of phytochemicals that can act as direct antioxidants, as well as modulators of antioxidant-response genes, indicating its potential role in alleviating diseases triggered by oxidative stresses. To the best of our knowledge, this is the first report revealing the antioxidant ability of tef extracts in a physiologically relevant human cell model.

What was old is new again: Phenotypic screening of a unique fungal library yields pyridoxatin, a promising lead against extensively resistant Acinetobacter baumannii (AB5075).

Due to the emergence of resistance, the World Health Organization considers Gram-negative pathogen Acinetobacter baumannii a top priority for therapeutic development. Using this priority pathogen and a phenotypic, agar plate-based assay, a unique library of extracts from 2,500 diverse fungi was screened for antimicrobial activity against a highly virulent, drug-resistant strain of A. baumannii (AB5075). The most potent hit from this screen was an extract from the fungus Tolypocladium sp., which was found to produce pyridoxatin. Another active extract from the fungi Trichoderma deliquescens was characterized and yielded trichokonin VII and trichokonin VIII. Evaluation of pyridoxatin against A. baumannii (AB5075) in a broth microdilution assay revealed a minimum inhibitory concentration (MIC) of 38 µM, compared to the known antibiotic levofloxacin with MIC of 28 µM. Mass spectrometry, Marfey's analysis and nuclear magnetic resonance spectroscopy analyses confirmed the structures of trichokonins VII and VIII to be consistent with previous reports. In an in vivo Galleria mellonella model, pyridoxatin tested at 150 mg/kg exhibited minimal toxicity (90% survival) and promising antimicrobial efficacy (50% survival) after 5 days. Trichokonins VII and VIII tested at 150 mg/kg were toxic to G. mellonella, with 20% survival and 40% survival after 5 days, respectively. The findings of this project suggest that pyridoxatin may serve as a lead compound for the development of antimicrobials against A. baumannii. They also demonstrate the value of the phenotypic screening approach employed herein.

Fabrication of Pulsatile Polymeric Microparticles Encapsulating Rabies Antigen.

The current guidelines for rabies post-exposure prophylaxis require multiple injections administered over several weeks. This can be disproportionately burdensome to those living in low- and middle-income countries (LMICs), where the majority of deadly exposures to rabies occur. Different drug delivery strategies have been explored to condense vaccine regimens to a single injection by encapsulating antigens into polymeric particles. However, harsh stressors during the encapsulation process can cause denaturation of the encapsulated antigen. This article describes a method for encapsulating the rabies virus (RABV) antigen into polymeric microparticles that exhibit tunable pulsatile release. This method, termed Particles Uniformly Liquified and Sealed to Encapsulate Drugs (PULSED), generates microparticles using soft lithography to create inverse polydimethylsiloxane (PDMS) molds from a multi-photon, 3D-printed master mold. Poly(lactic-co-glycolic acid) (PLGA) films are then compression-molded into the PDMS molds to generate open-faced cylinders that are filled with concentrated RABV using a piezoelectric dispensing robot. These microstructures are then sealed by heating the top of the particles, allowing the material to flow and form a continuous, nonporous polymeric barrier. Post-fabrication, an enzyme-linked immunosorbent assay (ELISA) specific to the detection of intact trimeric rabies virus glycoprotein is used to confirm the high recovery of immunogenic antigen from the microparticles.

A Scalable Platform for Fabricating Biodegradable Microparticles with Pulsatile Drug Release.

Pulsatile drug delivery systems have the potential to improve patient adherence and therapeutic efficacy by providing a sequence of doses in a single injection. Herein, a novel platform, termed Particles Uniformly Liquified and Sealed to Encapsulate Drugs (PULSED) is developed, which enables the high-throughput fabrication of microparticles exhibiting pulsatile release. In PULSED, biodegradable polymeric microstructures with an open cavity are formed using high-resolution 3D printing and soft lithography, filled with drug, and sealed using a contactless heating step in which the polymer flows over the orifice to form a complete shell around a drug-loaded core. Poly(lactic-co-glycolic acid) particles with this structure can rapidly release encapsulated material after delays of 10 ± 1, 15 ± 1, 17 ± 2, or 36 ± 1 days in vivo, depending on polymer molecular weight and end group. The system is even compatible with biologics, releasing over 90% of bevacizumab in its bioactive form after a two-week delay in vitro. The PULSED system is highly versatile, offering compatibility with crystalline and amorphous polymers, easily injectable particle sizes, and compatibility with several newly developed drug loading methods. Together, these results suggest that PULSED is a promising platform for creating long-acting drug formulations that improve patient outcomes due to its simplicity, low cost, and scalability.

A Widely Distributed Biosynthetic Cassette Is Responsible for Diverse Plant Side Chain Cross-Linked Cyclopeptides.

Cyclopeptide alkaloids are an abundant class of plant cyclopeptides with over 200 analogs described and bioactivities ranging from analgesic to antiviral. While these natural products have been known for decades, their biosynthetic basis remains unclear. Using a transcriptome-mining approach, we link the cyclopeptide alkaloids from Ceanothus americanus to dedicated RiPP precursor peptides and identify new, widely distributed split BURP peptide cyclase containing gene clusters. Guided by our bioinformatic analysis, we identify and isolate new cyclopeptides from Coffea arabica, which we named arabipeptins. Reconstitution of the enzyme activity for the BURP found in the biosynthesis of arabipeptin A validates the activity of the newly discovered split BURP peptide cyclases. These results expand our understanding of the biosynthetic pathways responsible for diverse cyclic plant peptides and suggest that these side chain cross-link modifications are widely distributed in eudicots.

Enhanced stability and clinical absorption of a form of encapsulated vitamin A for food fortification.

Food fortification is an effective strategy to address vitamin A (VitA) deficiency, which is the leading cause of childhood blindness and drastically increases mortality from severe infections. However, VitA food fortification remains challenging due to significant degradation during storage and cooking. We utilized an FDA-approved, thermostable, and pH-responsive basic methacrylate copolymer (BMC) to encapsulate and stabilize VitA in microparticles (MPs). Encapsulation of VitA in VitA-BMC MPs greatly improved stability during simulated cooking conditions and long-term storage. VitA absorption was nine times greater from cooked MPs than from cooked free VitA in rats. In a randomized controlled cross-over study in healthy premenopausal women, VitA was readily released from MPs after consumption and had a similar absorption profile to free VitA. This VitA encapsulation technology will enable global food fortification strategies toward eliminating VitA deficiency.

Diet-derived metabolites and mucus link the gut microbiome to fever after cytotoxic cancer treatment.

Not all patients with cancer and severe neutropenia develop fever, and the fecal microbiome may play a role. In a single-center study of patients undergoing hematopoietic cell transplant (n = 119), the fecal microbiome was characterized at onset of severe neutropenia. A total of 63 patients (53%) developed a subsequent fever, and their fecal microbiome displayed increased relative abundances of Akkermansia muciniphila, a species of mucin-degrading bacteria (P = 0.006, corrected for multiple comparisons). Two therapies that induce neutropenia, irradiation and melphalan, similarly expanded A. muciniphila and additionally thinned the colonic mucus layer in mice. Caloric restriction of unirradiated mice also expanded A. muciniphila and thinned the colonic mucus layer. Antibiotic treatment to eradicate A. muciniphila before caloric restriction preserved colonic mucus, whereas A. muciniphila reintroduction restored mucus thinning. Caloric restriction of unirradiated mice raised colonic luminal pH and reduced acetate, propionate, and butyrate. Culturing A. muciniphila in vitro with propionate reduced utilization of mucin as well as of fucose. Treating irradiated mice with an antibiotic targeting A. muciniphila or propionate preserved the mucus layer, suppressed translocation of flagellin, reduced inflammatory cytokines in the colon, and improved thermoregulation. These results suggest that diet, metabolites, and colonic mucus link the microbiome to neutropenic fever and may guide future microbiome-based preventive strategies.

Multidomain peptide hydrogel adjuvants elicit strong bias towards humoral immunity.

Adjuvants play a critical role in enhancing vaccine efficacy; however, there is a need to develop new immunomodulatory compounds to address emerging pathogens and to expand the use of immunotherapies. Multidomain peptides (MDPs) are materials composed of canonical amino acids that form injectable supramolecular hydrogels under physiological salt and pH conditions. MDP hydrogels are rapidly infiltrated by immune cells in vivo and have previously been shown to influence cytokine production. Therefore, we hypothesized that these immunostimulatory characteristics would allow MDPs to function as vaccine adjuvants. Herein, we demonstrate that loading antigen into MDP hydrogels does not interfere with their rheological properties and that positively charged MDPs can act as antigen depots, as demonstrated by their ability to release ovalbumin (OVA) over a period of 7-9 days in vivo. Mice vaccinated with MDP-adjuvanted antigen generated significantly higher IgG titers than mice treated with the unadjuvanted control, suggesting that these hydrogels potentiate humoral immunity. Interestingly, MDP hydrogels did not elicit a robust cellular immune response, as indicated by the lower production of IgG2c and smaller populations of tetramer-positive CD8+ T splenocytes compared to mice vaccinated alum-adjuvanted OVA. Together, the data suggest that MDP hydrogel adjuvants strongly bias the immune response towards humoral immunity while evoking a very limited cellular immune response. As a result, MDPs may have the potential to serve as adjuvants for applications that benefit exclusively from humoral immunity.

Employing Drug Delivery Strategies to Overcome Challenges Using TLR7/8 Agonists for Cancer Immunotherapy.

Toll-like receptors (TLRs) are a potential target for cancer immunotherapy due to their role in the activation of the innate immune system. More specifically, TLR7 and TLR8, two structurally similar pattern recognition receptors that trigger interferon and cytokine responses, have proven to be therapeutically relevant targets for cancer in numerous preclinical and clinical studies. When triggered by an agonist, such as imiquimod or resiquimod, the TLR7/8 activation pathway induces cellular and humoral immune responses that can kill cancer cells with high specificity. Unfortunately, TLR7/8 agonists also present a number of issues that must be overcome prior to broad clinical implementation, such as poor drug solubility and systemic toxic effects. To overcome the key limitations of TLR7/8 agonists as a cancer therapy, biomaterial-based drug delivery systems have been developed. These delivery devices are highly diverse in their design and include systems that can be directly administered to the tumor, passively accumulated in relevant cancerous and lymph tissues, triggered by environmental stimuli, or actively targeted to specific physiological areas and cellular populations. In addition to improved delivery systems, recent studies have also demonstrated the potential benefits of TLR7/8 agonist co-delivery with other types of therapies, particularly checkpoint inhibitors, cancer vaccines, and chemotherapeutics, which can yield impressive anti-cancer effects. In this review, we discuss recent advances in the development of TLR7/8 agonist delivery systems and provide perspective on promising future directions.

Hepatic organic anion transporting polypeptides mediate disposition of milk thistle flavonolignans and pharmacokinetic silymarin-drug interactions.

Silybum marianum (L.) Gaertn. (Asteraceae), commonly known as milk thistle, is a botanical natural product used to self-treat multiple diseases such as Type 2 diabetes mellitus and nonalcoholic steatohepatitis (NASH). An extract from milk thistle seeds (achenes), termed silymarin, is comprised primarily of several flavonolignans. Systemic concentrations of these flavonolignans can influence the potential biologic effects of silymarin and the risk for pharmacokinetic silymarin-drug interactions. The aims of this research were to determine the roles of organic anion transporting polypeptides (OATPs/Oatps) in silymarin flavonolignan disposition and in pharmacokinetic silymarin-drug interactions. The seven major flavonolignans from silymarin were determined to be substrates for OATP1B1, OATP1B3, and OATP2B1. Sprague Dawley rats were fed either a control diet or a NASH-inducing diet and administered pitavastatin (OATP/Oatp probe substrate), followed by silymarin via oral gavage. Decreased protein expression of Oatp1b2 and Oatp1a4 in NASH animals increased flavonolignan area under the plasma concentration-time curve (AUC) and maximum plasma concentration. The combination of silymarin inhibition of Oatps and NASH-associated decrease in Oatp expression caused an additive increase in plasma pitavastatin AUC in the animals. These data indicate that OATPs/Oatps contribute to flavonolignan cellular uptake and mediate the interaction between silymarin and NASH on pitavastatin systemic exposure.

Delivery of eupenifeldin via polymer-coated surgical buttresses prevents local lung cancer recurrence.

Lung cancer is the leading cause of cancer deaths worldwide. Unfortunately, high recurrence rates and poor survival remain despite surgical resection and conventional chemotherapy. Local drug delivery systems are a promising intervention for lung cancer treatment with the potential for improved efficacy with reduced systemic toxicity. Here, we describe the development of a chemotherapy-loaded polymer buttress, to be implanted along the surgical margin at the time of tumor resection, for achieving local and prolonged release of a new anticancer agent, eupenifeldin. We prepared five different formulations of buttresses with varying amounts of eupenifeldin, and additional external empty polymer coating layers (or thicknesses) to modulate drug release. The in vitro eupenifeldin release profile depends on the number of external coating layers with the formulation of the greatest thickness demonstrating a prolonged release approaching 90 days. Similarly, the long-term cytotoxicity of eupenifeldin-loaded buttress formulations against murine Lewis lung carcinoma (LLC) and human lung carcinoma (A549) cell lines mirrors the eupenifeldin release profiles and shows a prolonged cytotoxic effect. Eupenifeldin-loaded buttresses significantly decrease local tumor recurrence in vivo and increase disease-free survival in a lung cancer resection model.

Engineered PLGA microparticles for long-term, pulsatile release of STING agonist for cancer immunotherapy.

Activation of the stimulator of interferon gene (STING) pathway within the tumor microenvironment has been shown to generate a strong antitumor response. Although local administration of STING agonists has promise for cancer immunotherapy, the dosing regimen needed to achieve efficacy requires frequent intratumoral injections over months. Frequent dosing for cancer treatment is associated with poor patient adherence, with as high as 48% of patients failing to comply. Multiple intratumoral injections also disrupt the tumor microenvironment and vascular networks and therefore increase the risk of metastasis. Here, we developed microfabricated polylactic-co-glycolic acid (PLGA) particles that remain at the site of injection and release encapsulated STING agonist as a programmable sequence of pulses at predetermined time points that mimic multiple injections over days to weeks. A single intratumoral injection of STING agonist-loaded microparticles triggered potent local and systemic antitumor immune responses, inhibited tumor growth, and prolonged survival as effectively as multiple soluble doses, but with reduced metastasis in several mouse tumor models. STING agonist-loaded microparticles improved the response to immune checkpoint blockade therapy and substantially decreased the tumor recurrence rate from 100 to 25% in mouse models of melanoma when administered during surgical resection. In addition, we demonstrated the therapeutic efficacy of STING microparticles on an orthotopic pancreatic cancer model in mice that does not allow multiple intratumoral injections. These findings could directly benefit current STING agonist therapy by decreasing the number of injections, reducing risk of metastasis, and expanding its applicability to hard-to-reach cancers.

The Chemistry of Kratom [Mitragyna speciosa]: Updated Characterization Data and Methods to Elucidate Indole and Oxindole Alkaloids.

Two separate commercial products of kratom [Mitragyna speciosa (Korth.) Havil. Rubiaceae] were used to generate reference standards of its indole and oxindole alkaloids. While kratom has been studied for over a century, the characterization data in the literature for many of the alkaloids are either incomplete or inconsistent with modern standards. As such, full 1H and 13C NMR spectra, along with HRESIMS and ECD data, are reported for alkaloids 1-19. Of these, four new alkaloids (7, 11, 17, and 18) were characterized using 2D NMR data, and the absolute configurations of 7, 17, and 18 were established by comparison of experimental and calculated ECD spectra. The absolute configuration for the N(4)-oxide (11) was established by comparison of NMR and ECD spectra of its reduced product with those for compound 7. In total, 19 alkaloids were characterized, including the indole alkaloid mitragynine (1) and its diastereoisomers speciociliatine (2), speciogynine (3), and mitraciliatine (4); the indole alkaloid paynantheine (5) and its diastereoisomers isopaynantheine (6) and epiallo-isopaynantheine (7); the N(4)-oxides mitragynine-N(4)-oxide (8), speciociliatine-N(4)-oxide (9), isopaynantheine-N(4)-oxide (10), and epiallo-isopaynantheine-N(4)-oxide (11); the 9-hydroxylated oxindole alkaloids speciofoline (12), isorotundifoleine (13), and isospeciofoleine (14); and the 9-unsubstituted oxindoles corynoxine A (15), corynoxine B (16), 3-epirhynchophylline (17), 3-epicorynoxine B (18), and corynoxeine (19). With the ability to analyze the spectroscopic data of all of these compounds concomitantly, a decision tree was developed to differentiate these kratom alkaloids based on a few key chemical shifts in the 1H and/or 13C NMR spectra.

Drug Leads from Endophytic Fungi: Lessons Learned via Scaled Production.

Recently, the isolation and elucidation of a series of polyhydroxyanthraquinones were reported from an organic extract of a solid phase culture of an endophytic fungus, Penicillium restrictum (strain G85). One of these compounds, ω-hydroxyemodin (1: ), showed promising quorum-sensing inhibition against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) in both in vitro and in vivo models. The initial supply of 1: was 19 mg, and this amount needed to be scaled by a factor of 30 to 50 times, in order to generate material for further in vivo studies. To do so, improvements were implemented to enhance both the fermentation of the fungal culture and the isolation of this compound, with the target of generating > 800 mg of study materials in a period of 13 wk. Valuable insights, both regarding chemistry and mycology, were gained during the targeted production of 1: on the laboratory-scale. In addition, methods were modified to make the process more environmentally friendly by judicious choice of solvents, implementing procedures for solvent recycling, and minimizing the use of halogenated solvents.