Unveiling the regulatory mechanism of nimotuzumab on PD-L1 expression in head and neck squamous cell carcinoma patients: Implications for enhanced anticancer treatment strategies.

The overexpression of programmed death ligand 1 (PD-L1) is associated with resistance to anticancer therapies and poor prognosis in patients with head and neck squamous cell carcinoma (HNSCC). Nimotuzumab, a humanized anti-epidermal growth factor receptor (EGFR) mAb, has been widely used clinically for treating several solid tumors. However, whether its anticancer effect involves a reduction in PD-L1 expression remains unclear. The current study aimed to investigate the regulatory effects and underlying mechanism of nimotuzumab on PD-L1 expression in HNSCC both in vitro and in vivo. In vitro, nimotuzumab inhibited IFN-γ-induced PD-L1 upregulation at both the transcriptional and protein levels in the HNSCC cell lines. Subsequent mechanism research revealed that nimotuzumab suppressed IFN-γ-stimulated PD-L1 upregulation mainly by inhibiting phosphorylation of EGFR/MEK/ERK pathway, which was further validated by MEK and ERK inhibitors. In a HNSCC tumor-bearing model, nimotuzumab significantly decreased PD-L1 expression during tumor progression or chemotherapy, and this reduction was accompanied by increased sensitivity of the tumor to docetaxel and atezolizumab. Additionally, nimotuzumab reversed PD-L1 upregulation when combined with Taxol + Cisplatin (TP) induction chemotherapy regimens and improved the CD4+ and CD8+ T cells infiltration in HNSCC patients. These findings provide new insights into the anticancer mechanisms of nimotuzumab in HNSCC.

First-in-human study on pharmacokinetics, safety, and tolerability of single and multiple escalating doses of PA9159 nasal spray, a highly potent glucocorticoid in healthy Chinese volunteers.

OBJECTIVE: PA9159 (previously named VSG159) is a structurally novel and highly potent glucocorticoid that plays a role in the late development of autoimmune and inflammatory diseases. The current first-in-human ascending-dose study of the PA9159 nasal spray was conducted in healthy Chinese volunteers to evaluate its pharmacokinetics, safety, and tolerability. In addition, the effects of PA9159 on serum cortisol secretion were investigated. METHODS: This was a double-blinded, randomized, placebo-controlled clinical study that included four single-dose groups in the single ascending dose cohort (SAD) and two multiple-dose groups in the multiple ascending dose cohort (MAD), with dose ranges of 10-80 µg and 20-40 µg, respectively. PA9159 was administered bilaterally via nasal spray once only or once daily for seven days. Pharmacokinetic, safety, and tolerability profiles were evaluated. RESULTS: A total of 60 participants completed the study. PA9159 doses of up to 80 µg in the SAD and up to 40 µg in the MAD were shown to be safe and tolerable. The most common treatment-related AEs were mild and transient local nasal AEs. Morning serum cortisol levels approximately remained unchanged in both the single-dose and multiple-dose groups. PA9159 was quantified in 41.8 % (368/880) of the samples in all treatment groups, including 25.2 % (105/416) of the SAD and 56.7 % (263/464) of the MAD. The majority (>80.0 %) of PA9159 plasma concentrations ranged from 0.5 to 2 pg/mL in determined samples. The mean AUC0-t of PA9159 in the SAD was 0.91, 1.39±0.68, 11.40±9.91, and 46.30±25.80 h*pg/mL in the 10 to 80 ug single group. The mean terminal half-life time (t1/2) was 8.43 h and 8.97±2.28 h in 40 ug and 80 ug single group, respectively. The mean AUCss of PA9159 in the MAD was 31.70±7.04, 44.20±20.60 h*pg /mL, and the t1/2 was 16.00±4.18 h, 21.20±10.20 h in the 20 ug and 40 ug multiple groups, respectively. The median Tmax was approximately 6 h in both the SAD and MAD cohorts. CONCLUSIONS: The PA9159 nasal spray was generally safe and well tolerated, and the effects of PA9159 on serum cortisol levels were limited. The plasma concentration and systemic exposure to PA9159 were very low. These findings support the necessity for further clinical studies on PA9159 nasal spray in patients suffering from allergic rhinitis.

Quantification of 2-NBDG, a probe for glucose uptake, in GLUT1 overexpression in HEK293T cells by LC-MS/MS.

The growth and proliferation of most cancer cells involve the excessive uptake of glucose mediated by glucose transporters. An effective strategy for cancer therapy has been to inhibit the GLUTs that are usually overexpressed in a variety of tumor cells. 2-NBDG is a GLUT1 substrate that can be used as a probe for GLUT1 inhibitors. An accurate and simple assay for 2-NBDG in a HEK293T cell model overexpressing GLUT1 was developed using liquid chromatography-tandem mass spectrometry. Chromatographic separation was achieved using a Xbridge® Amide column (3.5 µm, 2.1 mm × 150 mm, Waters) with acetonitrile-water containing 2 µM ammonium acetate (80:20, v/v) at a flow rate of 0.25 mL/min. Mass detection was conducted in the parallel reaction monitoring (PRM) mode. The calibration curve for 2-NBDG showed good linearity in the concentration range of 5-500 ng/mL with satisfactory precision, a relative standard deviation ranging from 2.92 to 9.59% and accuracy with a relative error ranging from -13.14 to 7.34%. This method was successfully applied to quantify the uptake of GLUT1-mediated 2-NBDG, and the results clearly indicated inhibition of GLUT1 by WZB117 and quercetin (two potent glucose transporter inhibitors) in the GLUT1-HEK293T cell model. This study provides a convenient and accurate method for high-throughput screening of selective and promising GLUT1 inhibitors.

Design and synthesis of analogues of the sphingosine-1-phosphate receptor 1 agonist IMMH001 with improved phosphorylation rate in human blood.

IMMH001, which is a prodrug for sphingosine-1-phosphate receptor 1 (S1P1) agonist, is converted to the active form, its monophosphate ester (S)-IMMH001-P, by sphingosine kinase 1 (SphK1) and sphingosine kinase 2 (SphK2) in vivo. In this study, we designed head-piece-modified analogues of IMMH001 based on structural information and prepared them with an efficient modular synthetic strategy. The analogues showed higher phosphorylation rates in human blood than the parent compound. These results indicated that the pro-R hydroxymethyl in the head-piece-moiety of IMMH001 prevents the pro-S hydroxymethyl from being phosphorylated by the kinase and ATP. The analogues may have better therapeutic potential.

Comparison and identification of metabolic profiling of bicyclol in rats, dogs and humans in vitro and in vivo.

Bicyclol, a novel hepatoprotective agent, has been widely used to treat chronic viral hepatitis and drug-induced liver injury (DILI). However, its metabolic characteristics remains to be explored, especially in humans. The current study aimed to identify major metabolites and specific metabolizing enzymes involved in bicyclol metabolism in vitro and in vivo using high performance liquid chromatography coupled with Q-Exactive orbitrap mass spectrometry (HPLC-Q-Exactive Orbitrap/MS). After incubation with liver microsomes and oral administration to rats, dogs and humans, a total of nine metabolites of bicyclol were identified including M1 (methyl ester hydrolysate product), M2-M3 (demethylated bicyclol), M4-M5 (demethoxy or dehydroxymethyl bicyclol), M6 (glucuronidated bicyclol) and M7-M9 (glucuronide conjugates of metabolites). Among these metabolites, M2 and M3 were the major phase I metabolites mainly mediated by CYP2C19 and CYP3A4, while M6 was the dominant phase II metabolite primarily catalyzed by UGT2B4. In this study, species-related metabolic difference among rats, dogs and humans were observed. In humans and dogs, M6 (glucuronidated bicyclol) was the most abundant circulating metabolite (higher than the parent drug) in the blood after oral administration, while the parent drug was the highest in rats. M4 and M5 were rats-specific metabolites whereas M1 and M9 were absent in dogs in vivo. The metabolism of bicyclol was demonstrated as demethylation and glucuronidation mediated by multiple drug metabolizing enzymes in different species. Our findings systematically elucidated the metabolic sites and routes of bicyclol in human for the first time, which may be helpful for rational combined application in clinic and further study of metabolites-related efficacy or toxicity.

Design and synthesis of selective sphingosine-1-phosphate receptor 1 agonists with increased phosphorylation rates.

FTY720 and IMMH002, prodrugs for sphingosine-1-phosphate receptor 1 (S1P1) agonists, show inadequate and inconsistent levels of phosphorylation in humans compared to that in rats. In this study, FTY720 or IMMH002 analogues (21-24) were designed and synthesized with modified head pieces to improve the biotransformation of the prodrugs to the active phosphorylated forms. Target compounds were synthesized via a convergent route using the key and optically pure building block 9, which was first synthesized via asymmetrically catalyzed amination. The phosphorylation rates of these analogues in rat or human blood were compared. The new methyl-substituted analogue compound 21 showed higher phosphorylation rates in both rats and humans than the parent compound, whereas compound 23 showed improvements in rats, but not in humans. In pharmacokinetics studies of rats, compounds 21 and 23 both had higher levels of phosphorylation than FTY720 and IMMH002. Thus, our study not only yielded new compounds with therapeutic potential, but also showed species differences between rats and humans in response to the structural modifications, which might be useful for predicting the biotransformation behavior and efficacy of this class of prodrugs in the clinic.

S1P1-selective agonist prodrug IMMH002 is phosphorylated in rats to form an S-configured enantiomer: Synthesis, verification, and biological activity of the in vivo active metabolite.

IMMH002 (1), a prodrug for a sphingosine-1-phosphate receptor 1 (S1P1) agonist, is converted to the monophosphate ester, which has an immunomodulatory effect. Starting from prochiral amino alcohol 1, racemic and enantiomerically pure phosphates of 1 were synthesized. Pure enantiomers were obtained after the chiral resolution of the key intermediate by chiral high-performance liquid chromatography and the absolute configuration was determined by circular dichroism. In the in vitro homogeneous time-resolved fluorescence-IP1 functional assay, the (S)-enantiomer showed much higher S1P1 activity and selectivity than the (R)-enantiomer. In the pharmacokinetic study, the ex vivo o-phthaldialdehyde derivatization protocol showed that the phosphate of 1 in rats was the S-configured enantiomer with >99% enantiomeric excess.

Drug interaction study of flavonoids toward OATP1B1 and their 3D structure activity relationship analysis for predicting hepatoprotective effects.

Organic anion transporting polypeptide 1B1 (OATP1B1), a liver-specific uptake transporter, was associated with drug induced liver injury (DILI). Screening and identifying potent OATP1B1 inhibitors with little toxicity is of great value in reducing OATP1B1-mediated DILI. Flavonoids are a group of polyphenols ubiquitously present in vegetables, fruits and herbal products, some of them were reported to produce transporter-mediated DDI. Our objective was to investigate potential inhibitors of OATP1B1 from 99 flavonoids, and to assess the hepatoprotective effects on bosentan induced liver injury. Eight flavonoids, including biochanin A, hispidulin, isoliquiritigenin, isosinensetin, kaempferol, licochalcone A, luteolin and sinensetin exhibited significant inhibition (>50 %) on OATP1B1 in OATP1B1-HEK293 cells, which reduced the OATP1B1-mediated influx of methotrexate, accordingly decreased its cytotoxicity in OATP1B1-HEK293 cells and increased its AUC0-t in different extents in rats, from 28.27%-82.71 %. In bosentan-induced rat liver injury models, 8 flavonoids reduced the levels of serum total bile acid (TBA) and the liver concentration of bosentan in different degrees. Among them, kaempferol decreased the concentration most significantly, by 54.17 %, which indicated that flavonoids may alleviate bosentan-induced liver injury by inhibiting OATP1B1-mediated bosentan uptake. Furthermore, the pharmacophore model indicated the hydrogen bond acceptors and hydrogen bond donors may play critical role in the potency of flavonoids inhibition on OATP1B1. Taken together, our findings would provide helpful information for predicting the potential risks of flavonoid-containing food/herb-drug interactions in humans and alleviating bosentan -induced liver injury by OATP1B1 regulation.

Simultaneous determination of a promising anti-brain tumor agent CAT3 and its two major metabolites in mouse plasma and brain by a LC-MS/MS method.

A rapid and reproducible method with high selectivity was developed for simultaneous determination of a promising anti-brain tumor agent CAT3 and its two metabolites PF403 and GLU-PF403 in mouse plasma and brain. An economic deproteinization with septuple acetonitrile (v/v) was applied to pretreat the samples in this study. All analytes were well retained and separated on a CAPCELL CORE PC (2.7 µm, 2.1 mm I.D. × 150 mm, SHISEIDO Technologies) column with an eluting solvent of acetonitrile /water containing 0.1 % formic acid (v/v) at the flow rate of 0.2 mL per minute. The detection was carried out on a Q Exactive high resolution mass spectrometer equipped with a HESI ion source in parallel reaction monitoring (PRM) mode. The corresponding transitions for quantitation were 434.23→ 70.07 for CAT3, 350.17→70.07 for PF403, 526.21→70.07 for GLU-PF403, 364.19→70.07 for IS-1 and 625.18→317.07 for IS-2, respectively. A well-linear fit curve was achieved among the range of 0.1∼50 ng/mL for CAT3, 0.2∼100 ng/mL for PF403 and 2.5∼600 ng/mL for GLU-PF403 both in mouse plasma and brain homogenate. The intra-/inter-day accuracies of three analytes were within ±14.5 % and precisions were below to 13.44 %. The mean values of recovery of three compounds in mouse plasma and brain homogenate were among 98.06 ∼ 118.63 % and 81.04∼108.69 %. The analytes in NaF-treated ice cold blood of mouse was stable within tested 30 min. Plasma and brain homogenate samples had no obvious changes during all storage, sample treatment and analytic process of mouse plasma sample. The reproducible and reliable method was well employed to the research of CAT3 pharmacokinetic characteristics in mouse plasma and brain after a single intragastric administration at dose of 10 mg/kg.

Heterotropic activation of flavonoids on cytochrome P450 3A4: A case example of alleviating dronedarone-induced cytotoxicity.

The clinical drug-drug interactions mediated by heterotropic activation on cytochrome P450 (CYP450) kinetics, especially CYP3A4, have received wide concern in recent years. Flavonoids, a group of important natural substances with various pharmacological activities, distribute widely among vegetables, fruits and herbs. The frequent and numerous uses of flavonoids may increase the risk of food/herb-drug interactions. However, little is known about activation effects of flavonoids on CYP3A4. The aim of this study was to investigate activation of CYP3A4 by flavonoids, explore the molecular mechanism, and assess the biological effects on dronedarone (DND) induced toxicity. The results showed that flavone, tangeretin, sinensetin and 6-hydroxyflavone increased the cell viability by decreasing DND-induced cytotoxicity. These four flavonoids could activate the metabolism of DND in hamster pharmacokinetics study. Furthermore, both molecular docking and circular dichroism analysis partially illustrated the molecular mechanism of heterotropic activation. Finally, the pharmacophore model suggested B aromatic ring, hydrophobic groups at 7-position and hydrogen bond acceptors at 4-position may play a vital role in activation of flavonoids on CYP3A4. Taken together, our findings would provide useful information for predicting the potential risks of flavonoid-containing food/herb-drug interactions in humans.

Evaluation of inhibitory effects of flavonoids on breast cancer resistance protein (BCRP): From library screening to biological evaluation to structure-activity relationship.

Flavonoids are a group of polyphenols ubiquitously present in vegetables, fruits and herbal products, despite various known pharmacological activities, few researches have been done about the interaction of flavonoids with breast cancer resistance protein (BCRP). The present study was designed to investigate the inhibitory effects of 99 flavonoids on BCRP in vitro and in vivo and to clarify structure-activity relationships of flavonoids with BCRP. Eleven flavonoids, including amentoflavone, apigenin, biochanin A, chrysin, diosimin, genkwanin, hypericin, kaempferol, kaempferide, licochalcone A and naringenin, exhibited significant inhibition (>50%) on BCRP in BCRP-MDCKII cells, which reduced the BCRP-mediated efflux of doxorubicin and temozolomide, accordingly increased their cytotoxicity. In addition, co-administration of mitoxantrone with the 11 flavonoids increased the AUC0-t of mitoxantrone in different extents in rats. Among them, chrysin increased the AUC0-t most significantly, by 81.97%. Molecular docking analysis elucidated the inhibition of flavonoids on BCRP might be associated with Pi-Pi stacked interactions and/or potential Pi-Alkyl interactions, but not conventional hydrogen bonds. The pharmacophore model indicated the aromatic ring B, hydrophobic groups and hydrogen bond acceptors may play critical role in the potency of flavonoids inhibition on BCRP. Thus, our findings would provide helpful information for predicting the potential risks of flavonoid-containing food/herb-drug interactions in humans.

Derivatives of Natural Product Agrimophol as Disruptors of Intrabacterial pH Homeostasis in Mycobacterium tuberculosis.

This article reports the rational medicinal chemistry of a natural product, agrimophol (1), as a new disruptor of intrabacterial pH (pHIB) homeostasis in Mycobacterium tuberculosis (Mtb). Through the systematic investigation of the structure-activity relationship of 1, scaffold-hopping of the diphenylmethane scaffold, pharmacophore displacement strategies, and studies of the structure-metabolism relationship, a new derivative 5a was achieved. Compound 5a showed 100-fold increased potency in the ability to reduce pHIB to pH 6.0 and similarly improved mycobactericidal activity compared with 1 against both Mycobacterium bovis-BCG and Mtb. Compound 5a possessed improved metabolic stability in human liver microsomes and hepatocytes, lower cytotoxicity, higher selectivity index, and similar pKa value to natural 1. This study introduces a novel scaffold to an old drug, resulting in improved mycobactericidal activity through decreasing pHIB, and may contribute to the critical search for new agents to overcome drug resistance and persistence in the treatment of tuberculosis.

Inhibitory effects of flavonoids on P-glycoprotein in vitro and in vivo: Food/herb-drug interactions and structure-activity relationships.

Flavonoids are a class of polyphenol antioxygen, despite various known biological activities and therapeutic potential, scattered but not much is known about their interactions with drug transporters. P-glycoprotein (P-gp) as a cellular defense mechanism by effluxing its substrates has been widely investigated. The aim of this study was to investigate the inhibitory effects of 75 flavonoids on P-gp in vitro and in vivo and to illuminate the structure-activity relationships of flavonoids with P-gp. Five flavonoids, including tangeretin, sinensetin, isosinensetin, sciadopitysin and oroxylin A exhibited significant inhibition on P-gp in MDR1-MDCKIIcells, which reduced the P-gp-mediated efflux of paraquat and taxol and consequently increased their cell toxicity. In addition, co-administration of digoxin with five flavonoids increased the AUC0-t of digoxin in different extents in rats, from 19.84% to 81.51%. Molecular docking assays elucidated the inhibitory effect of flavonoids might be related to Pi interactions, but not hydrogen bonds. The pharmacophore model suggested the hydrophobic groups in B benzene ring may play a vital role in the potency of flavonoids inhibition on P-gp. Taken together, our findings would provide the basis for a reliable assessment of the potential risks of flavonoid-containing food/herb-drug interactions in humans.