Development of Zika Virus E Variants for Pseudotyping Retroviral Vectors Targeting Glioblastoma Cells.

A fundamental idea for targeting glioblastoma cells is to exploit the neurotropic properties of Zika virus (ZIKV) through its two outer envelope proteins, prM and E. This study aimed to develop envelope glycoproteins for pseudotyping retroviral vectors that can be used for efficient tumor cell infection. Firstly, the retroviral vector pNLlucAM was packaged using wild-type ZIKV E to generate an E-HIVluc pseudotype. E-HIVluc infection rates for tumor cells were higher than those of normal prME pseudotyped particles and the traditionally used vesicular stomatitis virus G (VSV-G) pseudotypes, indicating that protein E alone was sufficient for the formation of infectious pseudotyped particles. Secondly, two envelope chimeras, E41.1 and E41.2, with the E wild-type transmembrane domain replaced by the gp41 transmembrane and cytoplasmic domains, were constructed; pNLlucAM or pNLgfpAM packaged with E41.1 or E41.2 constructs showed infectivity for tumor cells, with the highest rates observed for E41.2. This envelope construct can be used not only as a tool to further develop oncolytic pseudotyped viruses for therapy, but also as a new research tool to study changes in tumor cells after the transfer of genes that might have therapeutic potential.

Metal-insulator-metal strip spectroscopic infrared photothermal absorber based on uniaxially oriented plasmonic lanthanum hexaboride films.

We report the fabrication of a mid-infrared device using LaB6 - Al2O3 - LaB6 trilayers, with an array of LaB6 strips as the top layer. Uniaxially oriented lanthanum hexaboride (LaB6) films self-organized in a (100) orientation were adopted together with a lithographic process using laser direct writing followed by reactive ion etching. The fabricated infrared absorbers based on our electromagnetic design exhibited excellent resonant absorption and flexible tunability by changing the periodicity and width of the top LaB6 strips. We examined the performance of epitaxial and sputtered LaB6 films by fabricating two different types of absorbers using sputtered LaB6(100) and epitaxial LaB6(100) films for the bottom mirror layers. Owing to a difference in crystallinity, the latter exhibited a lower background in the absorption spectra as well as in the thermal emission spectra, indicating its good spectral selectivity.

Development of film-forming gel containing nanoparticles for transdermal drug delivery.

Despite several studies on film-forming systems with the advantages of both the film and the hydrogel, there are still no effective systems for fast film formation with a high level of control over permeability. In this study, a film-forming system for the delivery of nanomedicine, termed a film-forming nanogel (FFN), was produced and investigated for the first time to meet this need. The objective of this research was to study a new generation of film-forming hydrogels (FFHs) loaded with curcumin nanoparticles (CUR-GNPs) for transdermal applications. FFHs were prepared by employing zein and HPMC 4000 as film-forming polymers. Meanwhile, CUR-GNPs were obtained by sonoprecipitation. The film-forming time, particle characteristics and FFN drug release profile were assessed. The optimized FFH had a smooth surface and a fast drying time of 6 min and 4.5 min in vitro and ex vivo, respectively. Additionally, high, sustained drug permeation from the FFN was observed after 24 h. The FFH containing CUR-GNPs showed potential for application in transdermal drug delivery with a fast film-forming time, uniform particle dispersion and high, sustained drug permeation.

Folic acid supplementation does not attenuate thermoregulatory or cardiovascular strain of older adults exposed to extreme heat and humidity.

NEW FINDINGS: What is the central question of this study? Does folic acid supplementation alleviate thermoregulatory and cardiovascular strain of older adults during exposure to extreme heat and humidity? What is the main finding and its importance? Folic acid supplementation for 6 weeks did not affect whole-limb blood flow/vasodilatation, core and skin temperatures, heart rate, blood pressure and cardiac output. Thus, 6 weeks of folic acid supplementation does not alleviate thermoregulatory or cardiovascular strain of healthy older adults exposed to extreme heat and humidity. ABSTRACT: Folic acid supplementation reverses age-related reductions in cutaneous vasodilatation during passive heating. However, it is unknown if folic acid supplementation alleviates thermoregulatory and cardiovascular strain experienced by older adults during heat exposure. We evaluated the effect of folic acid supplementation on thermoregulatory and cardiovascular responses of nine healthy older adults (61-72 years, 3 males/6 females) exposed to extreme heat and humidity. Participants rested at 42°C while relative humidity was increased from 30% to 70% in 2% increments every 5 min. The protocol was performed before (CON) and after (FOLIC) 6 weeks of folic acid supplementation (5 mg day-1 ). Local cutaneous vascular conductance (CVC, laser-Doppler flowmetry), forearm vascular conductance (FVC, Doppler ultrasound), mean skin and oesophageal temperatures, heart rate, blood pressure and cardiac output were measured. Folic acid supplementation increased fasting serum folate concentrations (P < 0.01). Absolute CVC was greater throughout the protocol following supplementation (CON: 1.29 ± 0.16 units mmHg-1 vs. FOLIC: 1.65 ± 0.24 units mmHg-1 , P < 0.01). However, normalized CVC (CON: 54 ± 8% vs. FOLIC: 59 ± 7%, P = 0.22), FVC (CON: 3.47 ± 0.76 ml mmHg-1 vs. FOLIC: 3.40 ± 0.56 ml mmHg-1 , P = 0.93), mean skin (P = 0.81) and oesophageal (CON: 36.87 ± 0.28°C vs. folic: 36.90 ± 0.25°C, P = 0.98) temperatures, heart rate (CON: 83 ± 10 beats min-1 vs. FOLIC: 84 ± 8 beats min-1 , P = 0.64), blood pressure (P = 0.71) and cardiac output (P = 0.20) were unaffected by folic acid supplementation. These results demonstrate that 6 weeks of folic acid supplementation does not alleviate thermoregulatory or cardiovascular strain of healthy older adults exposed to extreme heat and humidity.

Volume loading augments cutaneous vasodilatation and cardiac output of heat stressed older adults.

KEY POINTS: Age-related changes in cutaneous microvascular and cardiac functions limit the extent of cutaneous vasodilatation and the increase in cardiac output that healthy older adults can achieve during passive heat stress. However, it is unclear if these age-related changes in microvascular and cardiac functions maximally restrain the levels of cutaneous vasodilatation and cardiac output that healthy older adults can achieve during heat stress. We observed that rapid volume loading, performed during passive heat stress, augments both cutaneous vasodilatation and cardiac output in healthy older humans. These findings demonstrate that the microcirculation of healthy aged skin can further dilate during passive heat exposure, despite peripheral limitations to vasodilatation. Furthermore, healthy older humans can augment cardiac output when cardiac pre-load is increased during heat stress. ABSTRACT: Primary ageing markedly attenuates cutaneous vasodilatation and the increase in cardiac output during passive heating. However, it remains unclear if these responses are maximally restrained by age-related changes in cutaneous microvascular and cardiac functions. We hypothesized that rapid volume loading performed during heat stress would increase cardiac output in older adults without parallel increases in cutaneous vasodilatation. Twelve young (Y: 26 ± 5 years) and ten older (O: 69 ± 3 years) healthy adults were passively heated until core temperature increased by 1.5°C. Cardiac output (thermodilution), forearm vascular conductance (FVC, venous occlusion plethysmography) and cutaneous vascular conductance (CVC, laser-Doppler) were measured before and after rapid infusion of warmed saline (15 mL kg-1 , ∼7 min). While heat stressed, but prior to saline infusion, cardiac output (O: 6.8 ± 0.4 vs. Y: 9.4 ± 0.6 L min-1 ), FVC (O: 0.08 ± 0.01 vs. Y: 0.17 ± 0.02 mL (100 mL min-1  mmHg-1 )-1 ), and CVC (O: 1.29 ± 0.34 vs. Y: 1.93 ± 0.30 units mmHg-1 ) were lower in older adults (all P < 0.01). Rapid saline infusion increased cardiac output (O: +1.9 ± 0.3, Y: +1.8 ± 0.7 L min-1 ), FVC (O: +0.015 ± 0.007, Y: +0.048 ± 0.013 mL (100 mL min-1  mmHg-1 )-1 ), and CVC (O: +0.28 ± 0.10, Y: +0.29 ± 0.16 units mmHg-1 ) in both groups (all P < 0.01). The absolute increase in cardiac output and CVC were similar between groups, whereas FVC increased to a greater extent in young adults (P < 0.01). These results demonstrate that healthy older adults can achieve greater levels of cutaneous vasodilatation and cardiac output during passive heating.

Plasma hyperosmolality improves tolerance to combined heat stress and central hypovolemia in humans.

Heat stress profoundly impairs tolerance to central hypovolemia in humans via a number of mechanisms including heat-induced hypovolemia. However, heat stress also elevates plasma osmolality; the effects of which on tolerance to central hypovolemia remain unknown. This study examined the effect of plasma hyperosmolality on tolerance to central hypovolemia in heat-stressed humans. With the use of a counterbalanced and crossover design, 12 subjects (1 female) received intravenous infusion of either 0.9% iso-osmotic (ISO) or 3.0% hyperosmotic (HYPER) saline. Subjects were subsequently heated until core temperature increased ~1.4°C, after which all subjects underwent progressive lower-body negative pressure (LBNP) to presyncope. Plasma hyperosmolality improved LBNP tolerance (ISO: 288 ± 193 vs. HYPER: 382 ± 145 mmHg × min, P = 0.04). However, no differences in mean arterial pressure (P = 0.10), heart rate (P = 0.09), or muscle sympathetic nerve activity (P = 0.60, n = 6) were observed between conditions. When individual data were assessed, LBNP tolerance improved ≥25% in eight subjects but remained unchanged in the remaining four subjects. In subjects who exhibited improved LBNP tolerance, plasma hyperosmolality resulted in elevated mean arterial pressure (ISO: 62 ± 10 vs. HYPER: 72 ± 9 mmHg, P < 0.01) and a greater increase in heart rate (ISO: +12 ± 24 vs. HYPER: +23 ± 17 beats/min, P = 0.05) before presyncope. No differences in these variables were observed between conditions in subjects that did not improve LBNP tolerance (all P ≥ 0.55). These results suggest that plasma hyperosmolality improves tolerance to central hypovolemia during heat stress in most, but not all, individuals.

Plasma hyperosmolality attenuates skin sympathetic nerve activity during passive heat stress in humans.

KEY POINTS: Plasma hyperosmolality delays the onset for sweat production and cutaneous vasodilatation during heat stress in humans; however, the mechanism by which hyperosmolality exerts this effect remains unknown. This study examined if plasma hyperosmolality exerts a central and/or peripheral modulation of thermoregulatory function in humans. The main findings are that plasma hyperosmolality delays the increase in skin sympathetic nerve activity during whole-body passive heat stress in humans. In contrast, local intradermal infusion of hyperosmotic saline did not affect sweating or cutaneous vasodilatation. These results suggest that plasma hyperosmolality delays the onset threshold for sweating and cutaneous vasodilatation by inhibiting efferent thermoregulatory activity in humans. ABSTRACT: In humans, plasma hyperosmolality delays the onset of sweating and cutaneous vasodilatation during heat stress. However, it remains unknown if hyperosmolality exerts this effect through a central (i.e. CNS) and/or peripheral (i.e. effector organ) modulation of thermoregulatory activity. We examined if intravenous infusion of hyperosmotic saline affects skin sympathetic nerve activity (SSNA) during whole-body passive heating in healthy humans. Furthermore, we examined if local intradermal infusion of hyperosmotic saline affects sweating and cutaneous vasodilatation during passive heating. Following intravenous infusion of either 0.9% (ISO) or 3.0% (HYPER) NaCl saline, 12 subjects were passively heated until core temperature increased by ∼0.6°C. During each condition, sweating and cutaneous vascular conductance were measured over two intradermal microdialysis probes, one perfused with ISO saline and the other with HYPER saline. Intravenous infusion of HYPER saline increased plasma osmolality (294 ± 3 to 316 ± 5 mOsm kg(-1) H2O, P ≤ 0.01), which remained greater than ISO throughout heating. Plasma hyperosmolality delayed the mean body temperature onset of sweating (+1.24 ± 0.18 vs. +1.60 ± 0.18°C, P ≤ 0.01) and cutaneous vasodilatation (+1.15 ± 0.18 vs. +1.53 ± 0.22°C, P ≤ 0.01), and attenuated the increase in SSNA during heating (+147 ± 178 vs. +427 ± 281%, P ≤ 0.01). Intradermal infusion of HYPER saline increased baseline cutaneous vascular conductance (P ≤ 0.01), which did not increase further during the subsequent heating period (P = 0.11). In contrast, intradermal infusion of HYPER saline did not affect sweating (P = 0.99). These results provide direct evidence that plasma hyperosmolality exerts a central modulatory effect governing efferent thermoregulatory activity in humans.

Two new species of Cyrtodactylus (Squamata: Gekkonidae) from the karst forest of Hoa Binh Province, Vietnam.

We describe two new species of the genus Cyrtodactylus on the basis of a new reptile collection from the limestone karst forest of Hoa Binh Province, northwestern Vietnam. Cyrtodactylus otai sp. nov. from Hang Kia-Pa Co Nature Reserve and Cyrtodactylus bobrovi sp. nov. from Ngoc Son-Ngo Luong Nature Reserve can be distinguished from each other and from their congeners by their genetic distinction and morphological differences in number of precloacal pores, femoral scales, ventral scales, lamellae, subcaudals and dorsal tubercle arrangement, as well as in size and color pattern. In phylogenetic analyses, both new species are nested in a clade containing taxa from northwestern and northcentral Vietnam and northern Laos, i.e., C. bichnganae and C. cf. martini from northwestern Vietnam, C. puhuensis from northcentral Vietnam, and C. spelaeus, C. vilaphongi, and C. wayakonei from northern Laos.

P-selectin glycoprotein ligand regulates the interaction of multiple myeloma cells with the bone marrow microenvironment.

Interactions between multiple myeloma (MM) cells and the BM microenvironment play a critical role in the pathogenesis of MM and in the development of drug resistance by MM cells. Selectins are involved in extravasation and homing of leukocytes to target organs. In the present study, we focused on adhesion dynamics that involve P-selectin glycoprotein ligand-1 (PSGL-1) on MM cells and its interaction with selectins in the BM microenvironment. We show that PSGL-1 is highly expressed on MM cells and regulates the adhesion and homing of MM cells to cells in the BM microenvironment in vitro and in vivo. This interaction involves both endothelial cells and BM stromal cells. Using loss-of-function studies and the small-molecule pan-selectin inhibitor GMI-1070, we show that PSGL-1 regulates the activation of integrins and downstream signaling. We also document that this interaction regulates MM-cell proliferation in coculture with BM microenvironmental cells and the development of drug resistance. Furthermore, inhibiting this interaction with GMI-1070 enhances the sensitization of MM cells to bortezomib in vitro and in vivo. These data highlight the critical contribution of PSGL-1 to the regulation of growth, dissemination, and drug resistance in MM in the context of the BM microenvironment.

Hypoxia promotes dissemination of multiple myeloma through acquisition of epithelial to mesenchymal transition-like features.

The spread of multiple myeloma (MM) involves (re)circulation into the peripheral blood and (re)entrance or homing of MM cells into new sites of the BM. Hypoxia in solid tumors was shown to promote metastasis through activation of proteins involved in the epithelial-mesenchymal transition (EMT) process. We hypothesized that MM-associated hypoxic conditions activate EMT-related proteins and promote metastasis of MM cells. In the present study, we have shown that hypoxia activates EMT-related machinery in MM cells, decreases the expression of E-cadherin, and, consequently, decreases the adhesion of MM cells to the BM and enhances egress of MM cells to the circulation. In parallel, hypoxia increased the expression of CXCR4, consequently increasing the migration and homing of circulating MM cells to new BM niches. Further studies to manipulate hypoxia to regulate tumor dissemination as a therapeutic strategy are warranted.

LNA-mediated anti-miR-155 silencing in low-grade B-cell lymphomas.

miR-155 acts as an oncogenic miR in B-cell lymphoproliferative disorders, including Waldenstrom macroglobulinemia (WM) and chronic lymphocytic leukemia, and is therefore a potential target for therapeutic intervention. However, efficient targeting of miRs in tumor cells in vivo remains a significant challenge for the development of miR-155-based therapeutics for the treatment of B-cell malignancies. In the present study, we show that an 8-mer locked nucleic acid anti-miR-155 oligonucleotide targeting the seed region of miR-155 inhibits WM and chronic lymphocytic leukemia cell proliferation in vitro. Moreover, anti-miR-155 delivered systemically showed uptake in the BM CD19(+) cells of WM-engrafted mice, resulting in the up-regulation of several miR-155 target mRNAs in these cells, and decreased tumor growth significantly in vivo. We also found miR-155 levels to be elevated in stromal cells from WM patients compared with control samples. Interestingly, stromal cells from miR-155-knockout mice led to significant inhibition of WM tumor growth, indicating that miR-155 may also contribute to WM proliferation through BM microenvironmental cells. The results of the present study highlight the therapeutic potential of anti-miR-155-mediated inhibition of miR-155 in the treatment of WM.

Self-assembled nanonization of fatty acid-conjugated vaccine antigen for enhanced thermal stability.

The aim of this study was to evaluate the enhanced thermal stability and physicochemical properties of fattigated vaccine antigens. High molecular weight influenza hemagglutinin (Heg) was used as a model antigen because of low heat stability requiring cold chamber. Heg was conjugated with long-chain oleic acid (C18) and short-chain 3-decenoic acid (C10) to prepare fattigated Heg. Circular dichroism analysis revealed no significant changes in the three-dimensional structure post-conjugation. In the liquid state, the fattigated Heg was self-assembled into nanoparticles (NPs) due to its amphiphilic nature, with sizes of 136.27 ± 12.78 nm for oleic acid-conjugated Heg (HOC) and 88.73 ± 3.27 nm for 3-decenoic acid-conjugated Heg (HDC). Accelerated thermal stability studies at 60 °C for 7 days demonstrated that fattigated Heg exhibited higher thermal stability than Heg in various liquid or solid states. The longer-chained HOC showed better thermal stability than HDC in the liquid state, attributed to increased hydrophobic interactions during self-assembly. In bio-mimicking liquid states at 37 °C, HOC exhibited higher thermal stability than Heg. Furthermore, solid-state HOC with cryoprotectants (trehalose, mannitol, and Tween® 80) had significantly increased thermal stability due to reduced exposure of protein surface area via nanonization behavior. The current fattigation platform could be a promising strategy for developing thermostable nano vaccines of heat-labile vaccine antigens.

Nanonization and Deformable Behavior of Fattigated Peptide Drug in Mucoadhesive Buccal Films.

This study was tasked with the design of mucoadhesive buccal films (MBFs) containing a peptide drug, leuprolide (LEU), or its diverse nanoparticles (NPs), for enhanced membrane permeability via self-assembled nanonization and deformable behavior. An LEU-oleic acid conjugate (LOC) and its self-assembled NPs (LON) were developed. Additionally, a deformable variant of LON (d-LON) was originally developed by incorporating l-α-phosphatidylcholine into LON as an edge activator. The physicochemical properties of LON and d-LON, encompassing particle size, zeta potential, and deformability index (DI), were evaluated. MBFs containing LEU, LOC, and NPs (LON, d-LON) were prepared using the solvent casting method by varying the ratio of Eudragit RLPO and hydroxypropyl methylcellulose, with propylene glycol used as a plasticizer. The optimization of MBF formulations was based on their physicochemical properties, including in vitro residence time, dissolution, and permeability. The dissolution results demonstrated that the conjugation of oleic acid to LEU exhibited a more sustained LEU release pattern by cleaving the ester bond of the conjugate, as compared to the native LEU, with reduced variability. Moreover, the LOC and its self-assembled NPs (LON, d-LON), equivalent to 1 mg LEU doses in MBF, exhibited an amorphous state and demonstrated better permeability through the nanonization process than LEU alone, regardless of membrane types. The incorporation of lauroyl-L-carnitine into the films as a permeation enhancer synergistically augmented drug permeability. Most importantly, the d-LON-loaded buccal films showed the highest permeability, due to the deformability of NPs. Overall, MBF-containing peptide NPs and permeation enhancers have the potential to replace parenteral LEU administration by improving LEU druggability and patient compliance.

Transduction Efficiency of Zika Virus E Protein Pseudotyped HIV-1gfp and Its Oncolytic Activity Tested in Primary Glioblastoma Cell Cultures.

The development of new tools against glioblastoma multiforme (GBM), the most aggressive and common cancer originating in the brain, remains of utmost importance. Lentiviral vectors (LVs) are among the tools of future concepts, and pseudotyping offers the possibility of tailoring LVs to efficiently transduce and inactivate GBM tumor cells. Zika virus (ZIKV) has a specificity for GBM cells, leaving healthy brain cells unharmed, which makes it a prime candidate for the development of LVs with a ZIKV coat. Here, primary GBM cell cultures were transduced with different LVs encased with ZIKV envelope variants. LVs were generated by using the pNLgfpAM plasmid, which produces the lentiviral, HIV-1-based, core particle with GFP (green fluorescent protein) as a reporter (HIVgfp). Using five different GBM primary cell cultures and three laboratory-adapted GBM cell lines, we showed that ZIKV/HIVgfp achieved a 4-6 times higher transduction efficiency compared to the commonly used VSV/HIVgfp. Transduced GBM cell cultures were monitored over a period of 9 days to identify GFP+ cells to study the oncolytic effect due to ZIKV/HIVgfp entry. Tests of GBM tumor specificity by transduction of GBM tumor and normal brain cells showed a high specificity for GBM cells.

Defining the role of TORC1/2 in multiple myeloma.

Mammalian target of rapamycin (mTOR) is a downstream serine/threonine kinase of the PI3K/Akt pathway that integrates signals from the tumor microenvironment to regulate multiple cellular processes. Rapamycin and its analogs have not shown significant activity in multiple myeloma (MM), likely because of the lack of inhibition of TORC2. In the present study, we investigated the baseline activity of the PI3K/Akt/mTOR pathway TORC1/2 in MM cell lines with different genetic abnormalities. TORC1/2 knock-down led to significant inhibition of the proliferation of MM cells, even in the presence of BM stromal cells. We also tested INK128, a dual TORC1/2 inhibitor, as a new therapeutic agent against these MM cell lines. We showed that dual TORC1/2 inhibition is much more active than TORC1 inhibition alone (rapamycin), even in the presence of cytokines or stromal cells. In vitro and in vivo studies showed that p-4EBP1 and p-Akt inhibition could be predictive markers of TORC2 inhibition in MM cell lines. Dual TORC1/2 inhibition showed better inhibition of adhesion to BM microenvironmental cells and inhibition of homing in vivo. These studies form the basis for further clinical testing of TORC1/2 inhibitors in MM.

Mucoadhesive buccal tablet of leuprolide and its fatty acid conjugate: Design, in vitro evaluation and formulation strategies.

This study aimed to design mucoadhesive buccal tablets of leuprolide (LEU) and to manufacture and evaluate the properties of buccal tablets containing LEU-oleic acid conjugate (LOC) and self-assembled LEU-oleic acid nanoparticles (LON), which were developed in a previous study. Hydroxypropyl methylcellulose (HPMC 4000) was used as the mucoadhesive polymer, and tablets were prepared by direct compression. The formulations were characterized by weight, content uniformity, thickness, hardness, swelling index, disintegration time, mucoadhesion time, and drug release. The chosen formulation maintained an adhesion time of up to 6.43 h and a disintegration time of 4.10 h. Drug stability in the mucoadhesive tablets was confirmed after 2 h of storage in human mimic saliva (Phosphate buffer solution pH 6.8). Furthermore, the designed LEU formulation and the LOC and LON developed in a previous study were prepared as buccal tablets and compared. In the dissolution and permeation studies, LON-loaded buccal tablets showed the highest permeation rate. This study suggests that mucoadhesive buccal tablets containing self-assembled LON may effectively increase the medication adherence for pediatric and geriatric patients by improving the bioavailability and permeation rate of LEU.

Generation of Viral Particles with Brain Cell-Specific Tropism by Pseudotyping HIV-1 with the Zika Virus E Protein.

Flaviviruses are a family of RNA viruses that includes many known pathogens, such as Zika virus (ZIKV), West Nile virus (WNV), dengue virus (DENV), and yellow fever virus (YFV). A pseudotype is an artificial virus particle created in vitro by incorporating the flavivirus envelope proteins into the structure of, for example, a retrovirus such as human immunodeficiency virus type-1 (HIV-1). They can be a useful tool in virology for understanding the biology of flaviviruses, evaluating immune responses, developing antiviral strategies but can also be used as vectors for gene transfer experiments. This protocol describes the generation of a ZIKV/HIV-1 pseudotype developed as a new tool for infecting cells derived from a highly malignant brain tumor: glioblastoma multiforme grade 4.

Roles of Fatty Acid Chain Length and Enzyme-Oriented Drug Controlled Release from pH-Triggering Self-Assembled Fatty Acid Conjugated Quetiapine Nanosuspensions.

Background: Quetiapine (QTP) is a first-line antipsychotic drug, but its therapeutic druggability and patient adherence were limited due to high oral dose strength, low bioavailability and physicochemical/biopharmaceutical issues. Purpose: To investigate the roles of fatty acid chain length and enzyme-oriented QTP controlled release from pH-triggering self-assembled fatty acid conjugated QTP nanosuspensions (NSPs). Methods: QTP was conjugated with different chain length fatty acids (C10-decanoic acid, C14-myristic acid, C18-stearic acid) to obtain QTP-fatty acid conjugates (QFCs: QD, QM, QS) by exploiting 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/4-dimethylaminopyridine (EDC/DMAP) conjugation chemistry. Then, the solubility, partitioning coefficient (log P), cell viability and cleavage kinetics of QFCs were evaluated. The pH-triggering self-assembled behaviors of QFCs to form QTP-fatty acid NSPs (QDN, QMN, QSN) by varying pH, QFC concentration and proton-to-QTP ratios were characterized. The morphological images, critical micelle concentration (CMC), physicochemical properties and enzyme-oriented QTP controlled release of NSPs were examined. Results: Three QFCs were synthesized with different chain length fatty acids from QTP after desalting fumarate from QTP fumarate. The pH, QFC concentration and proton-to-quetiapine molar ratio could influence physicochemical properties and nanonization behaviors of QFCs. All three QFCs showed no effect on the viability of myoblast cells. The pH-triggering self-assembly of amphiphilic QFCs to form nanoparticles (NPs) occurred as the amine moiety of QTP was readily ionized in a strongly acidic environment (pH 1.2). Interestingly, the longer the fatty acid chain length, the lower water solubility, the higher log P (lipophilicity) and the smaller NP particle size were observed. The conversion rate of QFCs to liberate QTP by esterase in human plasma and liver S9 fractions was also inversely proportional to the fatty acid carbon chain length. Interestingly, the freeze-dried QMN showed the esterase-oriented controlled release of QTP over one month, unlike the initial burst release of QDN or the slowly delayed release pattern of QSN. Conclusion: A new pH-triggering self-assembled nanonization platform was developed using different chain length fatty acid conjugated QTP in low pH environment. By varying fatty acid chain length, the enzyme-oriented QTP controlled release dosage form was challenged to enhance the therapeutic effectiveness of QTP.

Cellular Efficacy of Fattigated Nanoparticles and Real-Time ROS Occurrence Using Microfluidic Hepatocarcinoma Chip System: Effect of Anticancer Drug Solubility and Shear Stress.

The objective of this study was to evaluate the effectiveness of organ-on-chip system investigating simultaneous cellular efficacy and real-time reactive oxygen species (ROS) occurrence of anticancer drug-loaded nanoparticles (NPs) using hepatocarcinoma cells (HepG2) chip system under static and hepatomimicking shear stress conditions (5 dyne/cm2). Then, the role of hepatomimetic shear stress exposed to HepG2 and drug solubility were compared. The highly soluble doxorubicin (DOX) and poorly soluble paclitaxel (PTX) were chosen. Fattigated NPs (AONs) were formed via self-assembly of amphiphilic albumin (HSA)-oleic acid conjugate (AOC). Then, drug-loaded AONs (DOX-AON or PTX-AON) were exposed to a serum-free HepG2 medium at 37 °C and 5% carbon dioxide for 24 h using a real-time ROS sensor chip-based microfluidic system. The cellular efficacy and simultaneous ROS occurrence of free drugs and drug-loaded AONs were compared. The cellular efficacy of drug-loaded AONs varied in a dose-dependent manner and were consistently correlated with real-time of ROS occurrence. Drug-loaded AONs increased the intracellular fluorescence intensity and decreased the cellular efficacy compared to free drugs under dynamic conditions. The half-maximal inhibitory concentration (IC50) values of free DOX (13.4 µg/mL) and PTX (54.44 µg/mL) under static conditions decreased to 11.79 and 38.43 µg/mL, respectively, under dynamic conditions. Furthermore, DOX- and PTX-AONs showed highly decreased IC50 values of 5.613 and 21.86 µg/mL, respectively, as compared to free drugs under dynamic conditions. It was evident that cellular efficacy and real-time ROS occurrence were well-correlated and highly dependent on the drug-loaded nanostructure, drug solubility and physiological shear stress.

Physicochemical and Biopharmaceutical Controllability of New Self-Assembled Fatty Acid Conjugated Leuprolide for the Enhanced Anticancer Activity.

Background: Leuprolide (LEU), a synthetic nonapeptide analog of naturally occurring gonadotropin-releasing hormone (GnRH), could exert a direct inhibitory activity on the proliferation of prostate cancer cells. However, the short half-life in blood and the biopharmaceutical problem of LEU limit this anticancer activity. Purpose: To improve its druggability for improving anticancer activity, the amine-group targeted LEU was conjugated with different chain lengths of saturated fatty acids (FAs). Methods: LEU-fatty acid conjugates (LFCs) were synthesized by exploiting N-hydroxysuccinimidyl (NHS) conjugation chemistry. The physicochemical properties and the self-assembled behaviors of the conjugates were extensively investigated. The in vitro anticancer activity of three LFCs was extensively studied in both 2D monolayer and 3D spheroid culture models of a prostate cancer cell line, PC3. Results: Three LFCs could be readily self-assembled into nanoparticles (LFNs) with a small size of around 100 nm, positive charges, and exhibited greater permeability rates compared to the same concentration of LEU, excluding LSN. The chain length of FA in conjugate was positively related to the selectivity index between cancer cells and non-cancerous cell lines. All LFCs showed a superior direct antiproliferative effect on cancer cells in the following order: LSC (98.9%) > LPC (86.7%) > LLC (75.0%) > LEU (8.9%) after repeat daily of the same dose strength of LEU for 4 days. In addition, the 3D spheroid model study indicates that all LFCs with a one-time treatment performed a long-acting inhibitory effect on tumor growth as compared to LEU after 7 days. Conclusion: The conjugation of LEU with different chain lengths of FAs could provide a novel strategy to improve peptide stability and exert an additional superior direct inhibitory effect for the treatment of several hormone-responsive tumor systems using therapeutic peptides.