Chicoric acid (CA) induces autophagy in gastric cancer through promoting endoplasmic reticulum (ER) stress regulated by AMPK.

Gastric cancer is one of the most common cancers leading to tumor-related deaths worldwide. Chicoric acid (CA) exhibits a variety of protective effects in different diseases. However, its role in regulating tumor progression has not been reported. Autophagy, as a conserved catabolic process, sustains cellular homoeostasis responding to stress to modulate cell fate. In the study, the effects of CA on gastric cancer were investigated. The results indicated that CA treatment markedly reduced the cell viability and induced apoptosis in gastric cancer cells, and prevented tumor growth in an established xenograft gastric cancer model. Furthermore, CA exposure significantly induced autophagy both in gastric cancer cells and tumor samples, as evidenced by the up-regulated expression of LC3II. Moreover, phosphorylated AMP-activated protein kinase (AMPK) and p70S6 kinase (p70s6k) expression were obviously promoted by CA in vitro and in vivo. Importantly, blocking AMPK activation abrogated CA-induced expression of LC3II in gastric cancer cells. In addition, endoplasmic reticulum (ER) stress in tumor samples or cells was markedly induced by CA treatment through promoting the expression of associated signals such as Parkin, protein kinase RNA-like ER kinase (PERK), activating transcription factors 4 (ATF4) and ATF6. Importantly, these effects were abolished by the inhibition of AMPK signaling. Collectively, our findings indicated that CA prevents human gastric cancer progression by inducing autophagy partly through the activation of AMPK, and represents an effective therapeutic strategy against gastric cancer development.

Development and validation of two liquid chromatography-tandem mass spectrometry methods for the determination of silibinin and silibinin hemisuccinate in human plasma.

To investigate the pharmacokinetics of silibinin and silibinin hemisuccinate in human plasma, two high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methods were developed and validated. The methods require a small volume of sample (100µL), and the recovery of the analytes was complete with a good reproducibility (CV% 1.7-9.5), after a simple protein precipitation. Naringenin was used as internal standard. The chromatographic methods provided a good separation of diastereoisomers A and B of both silibinin and silibinin hemisuccinate onto a Chromolith Performance RP18e 100mm×3mm column, with a resolution of peaks from plasma matrix in less than 6min. The methods precision values expressed as CV% were always ≤6.2% and the accuracy was always well within the acceptable 15% range. Quantification was performed on a triple-quadrupole tandem mass spectrometer by Selected Reaction Monitoring (SRM) mode, in a negative ion mode, via electrospray ionization (ESI). The lower limit of quantitation was set at 5.0ng/mL (silibinin) and 25.0ng/mL (silibinin hemisuccinate), and the linearity was validated up to 1000.0 and 12,500.0ng/mL, for silibinin and silibinin hemisuccinate, respectively, with correlation coefficients (R(2)) of 0.991 or better. The methods were suitable for pharmacokinetic studies and were successfully applied to human plasma samples from subjects treated intravenously with Legalon(®) SIL at the dose of 20mg/kg, expressed as silibinin.

Synthesis, transport and mechanism of a type I prodrug: L-carnitine ester of prednisolone.

Aerosol glucocorticoid medications have become more and more important in treating BA (bronchial asthma). Although these agents are dosed to directly target airway inflammation, adrenocortical suppression and other systematic effects are still seen. To tackle this problem in a novel way, two L-carnitine ester derivatives of prednisolone (as the model drug), namely, PDC and PDSC, were synthesized to increase the absorption of prednisolone across the human bronchial epithelial BEAS-2B cells by the organic cation/carnitine transporter OCTN2 (SLC22A5) and then to slowly and intracellularly release prednisolone. The transport of prednisolone, PDC and PDSC into the human bronchial epithelial BEAS-2B cells was in the order PDSC > prednisolone > PDC at 37 °C. It was found that PDSC displayed 1.79-fold increase of uptake compared to prednisolone. Transport of PDSC by BEAS-2B was temperature-, time-, and Na(+)-dependent and saturable, with an apparent K(m) value of 329.74 µM, suggesting the involvement of carrier-mediated uptake. An RT-PCR study showed that organic cation/carnitine transporters OCTN1 and OCTN2 are expressed in BEAS-2B cells, but little in HEK293T cells. The order of uptake by HEK293T was prednisolone > PDC > PDSC. In addition, the inhibitory effects of organic cations such as L-carnitine, ergothioneine, TEA(+) and ipratropium on PDSC uptake in BEAS-2B cells were in the order L-carnitine > ipratropium > TEA(+) > ergothioneine, whereas their inhibitory effects on PDSC uptake in HEK293T cells were negligible. Finally, in vitro LPS-induced IL-6 production from BEAS-2B was more and longer suppressed by PDSC than prednisolone and PDC. All of these results suggested PDSC may be an attractive candidate for asthma treatment.

Pharmacokinetics of SN2310, an injectable emulsion that incorporates a new derivative of SN-38 in patients with advanced solid tumors.

SN2310 is an injectable emulsion composed of vitamin E, a succinate derivative, as well as 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of irinotecan. Single intravenous doses of 15, 20, 25, and 30 mg/m(2) of SN2310 emulsion were administered in a total of 26 patients with advanced solid malignancies. Serial blood samples were collected and concentrations of SN2310, SN-38, and SN-38 glucuronide were assayed. Mean systemic clearance of SN2310 ranged between 1.91 and 2.02 L/h/m(2) . Peak concentrations of SN-38 were observed at the end of infusion, suggesting a fast metabolic conversion of SN2310 to its active form, SN-38. Mean t1/2 values of SN-38 across the 20-30 mg/m(2) dose levels (131-199 h) were 33-55-fold longer than those observed for SN2310. The systemic exposure of SN-38 increased in a proportional manner over the dose range studied. SN2310 emulsion displayed an improved safety profile as compared with irinotecan. The most significant safety risk was neutropenia. Considering the rapid formation of SN-38, the proportional increase in exposure levels, and its longer elimination half-life, less frequent dosing of SN2310 emulsion may be considered for the treatment of patients with advanced solid malignancies.

Metabolic aspects of acute tissue hypoxia during extracorporeal circulation and their modification induced by L-carnitine treatment.

In this study the authors examine the effects of acute hypoxia due to extracorporeal circulation (ECC) and the role played by L-carnitine treatment on some plasmatic metabolites linked to glycolytic cellular metabolism. To obtain biochemical data, 120 patients in extracorporeal circulation during aortopulmonary bypass surgery were evaluated. The patients received either sodium bicarbonate (40 patients), or L-carnitine during ECC (40 patients) or before and during ECC (40 patients), and plasma samples were collected before ECC, during ECC and after ECC. The levels of lactate and pyruvate showed significant alterations in sodium bicarbonate-treated patients, and there was also a considerable imbalance in the succinate/fumarate ratio. This means that tissue hypoxia due to ECC leads to cellular oxidative damage and to a considerable decrease in the intracellular energy pools. The use of L-carnitine antagonizes the oxidative stress, as is well documented by the levels of plasmatic metabolites which remain confined to normal amounts.

Assay of methylmalonic acid in the serum of patients with cobalamin deficiency using capillary gas chromatography-mass spectrometry.

To determine the incidence of elevated levels of serum methylmalonic acid in patients with cobalamin deficiency, we utilized a new capillary gas chromatographic-mass spectrometric technique to measure methylmalonic acid in the serum of 73 patients with clinically confirmed cobalamin deficiency. Values ranged from 55 to 22,300 ng/ml, and 69 of the 73 patients had values above the normal range of 19-76 ng/ml as determined for 50 normal blood donors. In the cobalamin-deficient patients, serum methylmalonic acid was significantly correlated with the serum folate level and the degree of neurologic involvement. Some patients with pernicious anemia who were intermittently treated with cyanocobalamin were found to have elevated serum levels of methylmalonic acid while free of hematologic and neurologic abnormalities. A cobalamin-deficient patient is described with a normal serum cobalamin and an elevated serum methylmalonic acid. We conclude that the ability to measure methylmalonic acid in human serum will be useful in studies designed to determine the incidence of cobalamin deficiency in various patient populations.

Quantitation of methylmalonic acid and other dicarboxylic acids in normal serum and urine using capillary gas chromatography-mass spectrometry.

Methylmalonic acid, succinic acid, and other dicarboxylic acids have been extracted and partially purified from serum and urine using ether extraction and high-performance liquid chromatography. The t-butyldimethylsilyl derivatives were prepared and analyzed using capillary gas chromatography-mass spectrometry with selected ion monitoring. The addition of [methyl-2H3]methylmalonic acid and [1,4-13C2]succinic acid to the starting samples made it possible to quantitate these two dicarboxylic acids. Normal ranges for methylmalonic acid and succinic acid were determined in human and rat serum and in human urine. The utilization of other internal standards would make it possible to quantitate malonic, dimethylmalonic, ethylmalonic, methylsuccinic, glutaric, and other dicarboxylic acids.

Protection of ischemic rabbit myocardium by glutamic acid.

Glutamic acid may protect the ischemic myocardium by increasing the flux through anaerobic pathways for ATP production. We tested this in isolated rabbit hearts that were treated with 0 or 2 mM glutamate. Hearts were stabilized for 30 min, subjected to ischemia for 30 min, and then reperfused for 30 min. Cardiac performance was defined by measuring peak left ventricular pressure (PLVDP) at the apex of a Starling curve and expressed as the %PLVDP attained during the preischemia period. Glutamate improved cardiac performance (%PLVDP, treated vs. untreated) after moderate ischemia (92 vs. 67), severe ischemia (79 vs. 65), and total ischemia (61 vs. 41). During severe ischemia, improved performance was associated with enhanced release (nmol X g wet wt -1 X min -1, treated vs. untreated) of alpha-ketoglutarate (2.3 vs. 1.3), succinate (21.7 vs. 12.3), and lactate (478 vs. 386). The ischemic myocardial content (nmol/mg myocardial protein, treated vs. untreated) of alpha-ketoglutarate (1.7 vs. 1.2) was increased by glutamate. The ischemic content of ATP (25.4 vs. 21.9) and succinate (15.7 vs. 12.1) showed a slight trend toward improvement under glutamate treatment. The study shows an association between improved postischemic cardiac performance and increased production of alpha-ketoglutarate and succinate during glutamate treatment.