Mussel-inspired protein-based nanoparticles for curcumin encapsulation and promoting antitumor efficiency.

Curcumin demonstrated therapeutic potential for cancer. However, its medical application is limited due to low solubility, poor stability and low absorption rate. Here, we used the mussel-inspired functional protein (MPKE) to fabricate the curcumin-carrying nanoparticle (Cur-MPKE) for encapsulating and delivering curcumin. The protein MPKE is composed of the mussel module and zwitterionic peptide. The Dopa group bonding characteristic of the mussel module was leveraged for the self-assembly of nanoparticles, while the superhydrophilic property of the zwitterionic peptide was utilized to enhance the stability of nanoparticles. As expected, MPKE and Cur are tightly bound through hydrogen bonds and dynamic imide bonds to form nanoparticles. Cur-MPKE showed improved solubility and stability in aqueous solutions as well as excellent biocompatibility. Besides, Cur-MPKE also exhibited pH-triggered release and enhanced uptake of curcumin by tumor cells, promoting the antioxidant activity and antitumor effect of curcumin. Moreover, systemic experiments of Cur-MPKE to rats demonstrated that Cur-MPKE significantly inhibited tumor tissue growth and proliferation without causing obvious systemic toxicity. This work provides a new strategy for fabricating the delivery system of curcumin with improved stability, sustainability and bioavailability.

[Screening and activity analysis of nanobodies against lymphocyte activation gene-3(LAG-3)].

Objective To generate the phage display nanobody library immunized by lymphocyte-activation gene 3 (LAG-3) and to validate the functional activity of obtained anti-LAG-3 nanobodies. Methods The peripheral blood cDNA library was isolated from the adult llama which was immunized by human LAG-3 protein. The nanobodies sequences were obtained by nested PCR and cloned into the phagemid vector pComb3XSS, then transformed into Escherichia coli XL1-Blue cells for library generation and quality analysis. Anti-LAG-3 specific nanobodies were screened by phage display and sequenced by next-generation sequencing. Nanobodies were cloned into pET-22b (+) vector and Escherichia coli BL21 (DE3) cells were used for protein expression. The proteins were purified by using the Prism A column, then HPLC-MS, ELISA, Western blot, and surface plasmon resonance technology (SPR) were performed to characterize the nanobodies. Results The library capacity of the nanobody phage immune library with great diversity was 7.20×108 CFU/mL. After four rounds of biopanning, three individual nanobodies with distinct amino acid sequences VHH-L1-3, VHH-L3-2 and VHH-L13-2 were picked. The purity of the purified nanobodies was more than 95%. All of these three nanobodies exhibited high binding affinities with recombinant human LAG-3 specifically, among which the KD value of VHH-L13-2 was 3.971×10-9 mol/L. VHH-L13-2 exhibited the inhibitory effects on the association of LAG-3 and its ligand FGL-1, and the half maximal inhibitory concentration (IC50) value was 15.58 nmol/L. Conclusion The anti-LAG-3 phage display nanobody library is generated successfully. The anti-LAG-3 nanobodies possess high specificity and binding affinity and exhibit the inhibitory effects on the association of LAG-3 and its ligand.

Pharmacokinetics of gallic acid and protocatechuic acid in humans after dosing with Relinqing (RLQ) and the potential for RLQ-perpetrated drug-drug interactions on organic anion transporter (OAT) 1/3.

CONTEXT: Relinqing granules (RLQ) are being used alone or in combination with antibacterial drugs to treat urological disorders. OBJECTIVE: This study investigates the pharmacokinetics of RLQ in humans and the potential for RLQ-perpetrated interactions on transporters. MATERIALS AND METHODS: Twelve healthy subjects (six women and six men) participated to compare single- and multiple-dose pharmacokinetics of RLQ. In the single-dose study, all 12 subjects received 8 g of RLQ orally. After a 7-d washout period, the subjects received 8 g of RLQ for seven consecutive days (t.i.d.) and then a single dose. Gallic acid (GA) and protocatechuic acid (PCA) in plasma and urine samples were analysed using LC-MS/MS. The transfected cells were used to study the inhibitory effect of GA (50-5000 µg/L) and PCA (10-1000 µg/L) on transporters OAT1, OAT3, OCT2, OATP1B1, P-gp and BCRP. RESULTS: GA and PCA were absorbed into the blood within 1 h after administration and rapidly eliminated with a half-life of less than 2 h. The mean peak concentrations of GA (102 and 176 µg/L) and PCA (4.54 and 7.58 µg/L) were lower in males than females, respectively. The 24 h urine recovery rates of GA and PCA were about 10% and 5%, respectively. The steady-state was reached in 7 d without accumulation. GA was a potent inhibitor of OAT1 (IC50 = 3.73 µM) and OAT3 (IC50 = 29.41 µM), but not OCT2, OATP1B1, P-gp or BCRP. DISCUSSION AND CONCLUSIONS: GA and PCA are recommended as PK-markers in RLQ-related pharmacokinetic and drug interaction studies. We should pay more attention to the potential for RLQ-perpetrated interactions on transporters.

Transporters (OATs and OATPs) contribute to illustrate the mechanism of medicinal compatibility of ingredients with different properties in yuanhuzhitong prescription.

Various medicinal ingredients with different tastes are combined according to the theory of compatibility in Chinese materia medica to achieve a better efficacy, while the mechanism was not very clear. Here, the authors studied the interaction between ingredients and human transporters such as the kidney transporters OAT1 and OAT3, the liver transporters OATP1B1 and OATP1B3, and the intestine transporter OATP2B1 to discern the compatibility mechanism of ingredients with different tastes in the Yuanhuzhitong preparation (YHP) comprising Corydalis yanhusuo (CYH) and Angelica dahurica (AD), which could relieve pain by restraining the central system. The results show that tetrahydropalmatine (TDE), the major component of CYH, could be transported by OAT3 into kidney, OATP1B1 and OATP1B3 into liver, while imperatorin (IPT) and isoimperatorin (ISP), the two key components of AD, and AD extract showed strong inhibition to OAT1 and OAT3. What's more, AD extract also exerted strongly inhibition to human transporters OATP1B1 and OATP1B3. It was also detected that IPT, ISP, and AD extract significantly downregulated the expression of Oatp1a1, Oatp1a4, and Oatp1b2 of liver in mice. The in vivo results show that the concentration of TDE in liver and kidney significantly decreased, while the TDE concentration in blood and brain were both significantly enhanced in the presence of IPT, ISP, and AD extract. These results suggest that the ingredients in AD with pungent taste could enhance the exposure of TDE in blood and brain by inhibiting the uptake of TDE in liver and kidney. That is to say, TDE with bitter taste could "flood up" into the central nervous system to play its therapeutic effect by the cut-off of that into liver and kidney in the presence of ingredients within AD. This paper not only proves the meridian distribution of CYH in liver and kidney with the role of OAT3, OATP1B1, and OATP1B3, but also illustrates how to improve the efficacy of CYH by reasonable compatibility with AD. This study may offer a valuable clue to illustrate the mechanism of compatibility theory.

The influence of genetic polymorphisms in drug metabolism enzymes and transporters on the pharmacokinetics of different fluvastatin formulations.

The purpose of the present study was to investigate the impact of genetic polymorphism on fluvastatin pharmacokinetics. In addition, we compared the fluvastatin pharmacokinetics differences between extended-release (ER) 80 mg tablet and immediate-release (IR) 40 mg capsule in terms of drug metabolism enzyme and transporter genetic polymorphisms. In this open-label, randomized, two-period, two-treatment, crossover study (n = 24), effects of ABCG2, SLCO1B1, ABCB1, CYP2C9 and CYP3A5 polymorphisms on the pharmacokinetics of fluvastatin were analyzed. The administration dosage for IR 40 mg and ER 80 mg were twice and once daily, respectively, for total 7 d. Blood samples for pharmacokinetic evaluation were taken on the 1st and 7th d. The lower exposure following ER was observed. For ER tablets, SLCO1B1 T521C genotype correlated with AUC0-24 of repeat doses (P = 0.010). SLCO1B1 T521C genotype had no statistically significant effect on AUC0-24 of IR capsule of fluvastatin after single or repeated doses. In vitro study demonstrated that when the concentration of fluvastatin was low (< 1 µmol/l), the uptake of fluvastatin in the HEK293-OATP1B1 with SLCO1B1 521TT (Km =0.18 µmol/l) was faster than that with SLCO1B1 521CC (Km =0.49 µmol/l), On the other hand, when concentration reached to higher level (> 1 µmol/l), transport velocity of fluvastatin by HEK293-OATP1B1 with SLCO1B1 521TT (Km  = 11.4 µmol/l) and with SLCO1B1 521TCC (Km =15.1 µmol/l) tend to be the same. It suggests that the increased effect of SLCO1B1 T521C genotype on ER formulation of fluvastatin was mainly caused by lower blood concentrations. We recommend that formulation should be incorporated into future pharmacogenomics studies.

KLF2 regulates eNOS uncoupling via Nrf2/HO-1 in endothelial cells under hypoxia and reoxygenation.

Kruppel-like factor 2 (KLF2) regulates endothelial functions by modulating endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) pathway. Tetrahydrobiopterin (BH4) and S-glutathionylation of eNOS play essential roles in eNOS uncoupling and activation. However, the influence of KLF2 on eNOS uncoupling and the mechanism of eNOS activation still remain unknown. A hypoxia and reoxygenation (H/R) model of human umbilical vein endothelial cells (HUVECs) was utilized in this study. Cell viability and the eNOS uncoupling-related oxidative stress index were measured. The Nrf2 inhibitor ML385 and HO-1 siRNA were used to elucidate the mechanism of activation. The results show that overexpression of KLF2 increased the cell viability, reduced the lactate dehydrogenase leakage rate, downregulated the generation of O2•- and ONOO-, and increased NO levels and eNOS activity. Overexpression of KLF2 also increased the BH4/BH2 ratio and the GSH/GSSG ratio, thus significantly improving eNOS uncoupling in the H/R model. KLF2 has no regulatory effect on the upstream-associated proteins in eNOS activation. However, when combined with the Nrf2 inhibitor or HO-1 siRNA, the regulatory effect of KLF2 on eNOS uncoupling was strongly reduced. These results suggest that KLF2 could improve eNOS uncoupling via Nrf2/HO-1 in H/R-induced endothelial injury.

Identification of key transporters mediating uptake of aconitum alkaloids into the liver and kidneys and the potential mechanism of detoxification by active ingredients of liquorice.

Aconite as a commonly used herb has been extensively applied in the treatment of rheumatoid arthritis, as pain relief, as well as for its cardiotonic actions. Aconitum alkaloids have been shown to be the most potent ingredients in aconite, in terms of efficacy against disease, but they are also highly toxic. Apart from neurological and cardiovascular toxicity exposed, the damage to hepatocytes and nephrocytes with long-term use of aconitum alkaloids should also be carefully considered. This study attempted to investigate the critical role of uptake transporters mediating the transport of aconitum alkaloids into the liver and the kidneys. The resulting data revealed that hOATP1B1, 1B3, hOCT1 and hOAT3 were mainly involved in the uptake of aconitum alkaloids. Additionally, the inhibitory effects of bioactive ingredients of liquorice on uptake transporters were screened and further confirmed by determining the IC50 values. The in vitro study suggested that liquorice might lower the toxicity of aconite by reducing its exposure in the liver and/or kidneys through inhibition of uptake transporters. Eventually, the in vivo study was indicative of detoxification of liquorice by decreasing the exposure of aconitine as representative compound in liver after co-administration, even though the exposure in kidney altered was less significant. In summary, hOATP1B1, 1B3, hOCT1 and hOCT3 were determined as the key uptake transporters mediating the transport process of aconitum alkaloids into the liver and/or kidneys, and liquorice may alleviate the toxicity caused by reduction of exposure through inhibition of those key uptake transporters.

The effect of polymorphism of uric acid transporters on uric acid transport.

The abnormal metabolism of uric acid results in many disease such as chronic kidney disease, hyperuricemia, nephrolithiasis, gout, hypertension, vascular disease and so on. Serum uric acid levels are maintained by the balance between production and elimination. There are many factors that maintain the balance of serum uric acid. One of them is transporters which are responsible for the debouchment of uric acid within blood. The transport and excretion of uric acid is a complicated procedure which is related with various transporters such as OAT1, OAT3, OAT4, URAT1, GLUT9, BCRP, MRP4, NPT1, NTP4, and so on. In recent years, a large number of genome-wide association studies have shown that the single nucleotide polymorphisms of uric acid transporters were closely related to serum uric acid level. What's more, some mutations on these gene locus may also break the balance of serum uric acid. Here, the polymorphisms of uric acid transporters closely related with the serum uric acid balance were reviewed and discussed because of their important significance in clinical therapy for a precision medicine. The mechanism of metabolic diseases with gene variation may provide new strategy for the design and development of innovative drug to treat diseases with uric acid metabolic disturbance.

Pharmacokinetics, tissue distribution, and excretion of FGF-21 following subcutaneous administration in rats.

As one of the fibroblast growth factor (FGF) superfamily, FGF-21 has been extensively investigated for its functions and roles since its discovery. It has been demonstrated to be one of the key regulators for glucose and lipid metabolism, and exhibits beneficial effects on cardiovascular disease. However, studies focusing on its pharmacokinetic behavior in vivo as a novel therapeutic agent have not been reported. In the present study, rapid and sensitive analytical approaches including radioactivity assay and assay after precipitation/separation by high performance liquid chromatography (HPLC) were established to determine the content of FGF-21 tagged with 125 I in plasma, tissue, and excrement. The results indicated that FGF-21 were quickly absorbed into systematic circulation and slowly eliminated; Cmax and exposure increased in a dose-dependent manner, exhibiting a typical linear pharmacokinetic pattern. Tissue distribution also confirmed that the kidney is the primary organ for FGF-21 to be distributed, even though radioactivity of FGF-21 was recovered in all tissues examined. In addition, the results also supported that urinary excretion was the critical route for FGF-21 to be eliminated. The study fully clarifies the pharmacokinetic behavior of FGF-21 and can provide valuable information and support further safety and toxicology development.

New Insight into Polydopamine@ZIF-8 Nanohybrids: A Zinc-Releasing Container for Potential Anticancer Activity.

Despite the initial evidence on the role of zinc and zinc transporters in cancer prevention, little attention has been paid to the zinc-derived compounds. In the present work, we reported a strategy to prepare a kind of zinc-releasing container with enhanced biocompatibility and release dynamics using ZIF-8 nanocrystals as the sacrificial templates. Transmission electron microscopy (TEM) analysis demonstrated that the ZIF-8 nanocrystals were gradually etched out in the aqueous media within 48 h, resulting in hollow nanocapsules. Notably, we found the self-polymerization of dopamine can form nanoshells around the ZIF-8 nanocrystals, which served as a type of functional membranes during the release of zinc. More interestingly, PDA@ZIF-8⁻based nanohybrids expressed stronger inhibition to the cancer cell growth, which implied that the nanohybrids could be a drug carrier for chemotherapy. This study broadens the biomedical application of ZIF-8 and also provides a versatile strategy toward the development of multifunctional delivery system.

Zeolitic imidazolate framework-8 (ZIF-8) as a sacrificial template: one-pot synthesis of hollow poly(dopamine) nanocapsules and yolk-structured poly(dopamine) nanocomposites.

Hollow poly(dopamine) (PDA) nanocapsules and yolk-structured PDA nanocomposites were prepared by an aqueous one-pot synthesis method utilizing zeolitic imidazolate framework-8 (ZIF-8) nanocrystals as a sacrificial template without any special etchant. The resulting PDA nanocapsules show negligible cytotoxicity in HeLa cells after incubation for 48 h at various doses, which implies their potential as candidates for practical applications in drug transport and targeting.

The Targeted-liposome Delivery System of Antitumor Drugs.

The liposome delivery system has been intensively explored as novel drug delivery system (DDS) for antitumor drugs, due to its safety, selective cytotoxicity, long circulation and slow elimination in blood, which is favorable for cancer therapy. The liposome-based chemotherapeutics are used to treat a variety of cancers to enhance the therapeutic index of antitumor drugs. Here, the author reviewed the important targets for cancer therapy and the pharmacokinetic behavior of liposomal drugs in vivo, as well as the application of the targeting liposomal system in cancer therapy. Considering further application for clinical use, the great challenges of the liposome-based delivery system were also proposed as follows: 1) prepare stealth liposome with steric stabilization and further enhance the therapeutic effects and safety; 2) explore more safe clinical targets and complementary or different types of targeting liposome; 3) thirdly, more investment is needed on the research of pharmacokinetics of the elements such as the ligands (antibody), PEG and lipids of liposome delivery system as well as safety evaluation. Considering the complex process of the liposomal encapsulation drugs in vivo, the author inferred that there are maybe different forms of the encapsulation drug to be internalized by the tumor tissues at the same time and space, although there are little reports on it.

Effects of Drug Transporters on Pharmacological Responses and Safety.

Recently, it is realized that transporters, apart from enzymes, play a key role in drug metabolism and pharmacokinetics. More and more pharmaceutical researchers focused on transporter study and found that drug transporters not only involved in pharmacokinetics including absorption, distribution, metabolism and excretion (ADME). but also in Drug-Drug interactions (DDIs). DDIs induced by drug transporters are the important safety evaluation factors which have to be taken into account at stage of drug discovery and development. Therefore, it should pay more attention to the studies on step of preclinical and clinical trial. In this review, the author focused on the effects of drug transporters on pharmacological and safety responses, such as the effects on plasma elimination half-lives, on drug accumulation in body after repeated dosing, on potentiating either pharmacological or adverse effects and molecular mechanisms of transporter-mediated DDIs. Present studies showed that DDIs involving the drug transporters including ABC transporters, organic anion and cation transporters, peptide transporters, monocarboxylate transporters, nucleoside transporters and folate transporters, and the possible side effects derived from clinical combination therapy must pay attention. The author also discussed the molecular mechanisms of transporter-mediated DDIs by the data obtained from preclinical and clinical studies, and inferred the available curative effects and the potential risk of the drug combination involving these drug transporters, which provides a reference for the safety of clinical medication and a consideration for a successful drug discovery. This article carefully reviewed transporter-based DDIs and highlighted areas that DDIs were poorly predicted through transporters or areas are still confronted with challenges in future.

Aspartate-modified doxorubicin on its N-terminal increases drug accumulation in LAT1-overexpressing tumors.

L-type amino acid transporter 1 (LAT1), overexpressed on the membrane of various tumor cells, is a potential target for tumor-targeting therapy. This study aimed to develop a LAT1-mediated chemotherapeutic agent. We screened doxorubicin modified by seven different large neutral amino acids. The aspartate-modified doxorubicin (Asp-DOX) showed the highest affinity (Km = 41.423 µmol/L) to LAT1. Aspartate was attached to the N-terminal of DOX by the amide bond with a free carboxyl and a free amino group on the α-carbon atom of the Asp residue. The product Asp-DOX was characterized by HPLC/MS. In vitro, Asp-DOX exerted stronger inhibition on the cancer cells overexpressing LAT1 and the uptake of Asp-DOX was approximately 3.5-fold higher than that of DOX in HepG2 cells. Pharmacokinetic data also showed that Asp-DOX was expressed over a longer circulation time (t1/2 = 49.14 min) in the blood compared to DOX alone (t1/2 = 15.12 min). In HepG2 and HCT116 tumor-bearing mice, Asp-DOX achieved 3.1-fold and 6.4-fold accumulation of drugs in tumor tissue, respectively, than those of the unmodified DOX. More importantly, treatment of tumor-bearing mice with Asp-DOX showed a significantly stronger inhibition of tumor growth than mice treated with free DOX in HepG2 tumor models. Furthermore, after Asp modification, Asp-DOX avoided MDR mediated by P-glycoprotein. These results suggested that the Asp-DOX modified drug may provide a new treatment strategy for tumors that overexpress LAT1 and MDR1.