Exosomes regulate doxorubicin resistance in breast cancer via miR-34a-5p/NOTCH1.

Breast cancer (BRCA) is the most common cancer among women. Adriamycin (ADR), also known as doxorubicin (Dox), is a commonly used chemotherapeutic agent for BRCA patients, however, the susceptibility of tumor cells to develop resistance to Dox has severely limited its clinical use. One new promising therapeutic target for breast cancer patients is exosomes. The objective of this study was to investigate the role of exosomes in regulating Dox resistance in BRCA. In this study, the exosomes from both types of cells were extracted by differential centrifugation. The effect of exosomes on drug resistance was assessed by laser confocal microscopy, MTT assay, and qRT-PCR. The miRNA was transfected into cells using Lipofectamine 2000, which was then evaluated for downstream genes and changes in drug resistance. Exosomes from MCF-7 cells (MCF-7/exo) and MCF-7/ADR cells (ADR/exo) were effectively extracted in this study. The ADR/exo was able to endocytose MCF-7 cells and make them considerably more resistant to Dox. Moreover, we observed a significant difference in miR-34a-5p expression in MCF-7/ADR and ADR/exo compared to MCF-7 and MCF-7/exo. Among the miR-34a-5p target genes, NOTCH1 displayed a clear change with a negative correlation. In addition, when miR-34a-5p expression was elevated in MCF-7/ADR cells, the expression of miR-34a-5p in ADR/exo was also enhanced alongside NOTCH1, implying that exosomes may carry miRNA into and out of cells and perform their function. In conclusion, exosomes can influence Dox resistance in breast cancer cells by regulating miR-34a-5p/NOTCH1. These findings provide novel insights for research into the causes of tumor resistance and the enhancement of chemotherapy efficacy in breast cancer.

Screening of Peptides that Specifically Binds to M3-M4 Extracellular Domain of Sodium Pump α1 Subunit and Analysis of Their Bioactivity In Vitro and In Vivo.

Interaction between ouabain (OUA) and Na+/K+-pump remains in the current focus of hypertension research. This study aimed to find an oligopeptide that would antagonize the inhibitory effect of endogenous OUA on Na+/K+-pump and examine its activity at the cellular and organism levels. To this end, Phage Random 12 Peptide Library was employed to screen for specific polypeptide ligands that interact with M3-M4 extracellular domain of Na+/K+-pump α1 subunit known as OUA-binding site. Synthetic sequence ILEYTWLEAGGGS of extracellular domain M3-M4 of Na+/K+-pump α1 subunit was used as the target. The phage positive clones were screened and identified using the phage library and double sandwich ELISA. DNA was extracted and sequenced to synthesize 3 peptide ligands to Na+/K+-pump: P-A, P-B, and P-C. We also studied the effects of the short peptide with the highest potency for countering OUA on proliferation and apoptosis of EA.hy926 vascular endothelial cells and on systolic BP in spontaneously hypertensive rats (SHR). The effect of peptide P-A on proliferation (stimulation with physiological concentrations of OUA) and on apoptosis (stimulation with OUA in high concentrations) of EA.hy926 vascular endothelial cells was assessed by the MTT test and flow cytometry, respectively. In SHR rats, intravenous injection of P-A decreased systolic BP. Oligopeptide P-A competitively antagonized the inhibitory action of OUA on Na+/K+-pump, OUA-induced proliferation, and OUA-provoked apoptosis of cultured EA.hy926 cells. Our findings open vista for the emergence of novel hypertensive drugs.

Paris saponin II-induced paraptosis-associated cell death increased the sensitivity of cisplatin.

Paris Saponin II (PSII) has been regarded as an effective and imperative component isolated from Rhizoma Paridis saponins (RPS) and exhibited strong anti-tumor effects on a variety of cancer. Our results revealed that human non-small lung cancer cell lines NCI-H460 and NCI-H520 were exposed to 1 µM of PSII, which inhibited the proliferation of lung cancer cells and activated apoptosis, autophagy and paraptosis. PSII induced paraptosis-associated cell death prior to apoptosis and autophagy. It induced paraptosis based on ER stress through activation of the JNK pathway. Meanwhile, PSII increased the cytotoxicity of cisplatin through paraptosis-associated pathway. All in all, PSII induced paraptosis based on induction of non-apoptotic cell death, which would be a possible approach to suppress the multi-drug resistant to apoptosis.

Efficient Corrections for DFT Noncovalent Interactions Based on Ensemble Learning Models.

Machine learning has exhibited powerful capabilities in many areas. However, machine learning models are mostly database dependent, requiring a new model if the database changes. Therefore, a universal model is highly desired to accommodate the widest variety of databases. Fortunately, this universality may be achieved by ensemble learning, which can integrate multiple learners to meet the demands of diversified databases. Therefore, we propose a general procedure for learning ensemble establishment based on noncovalent interactions (NCIs) databases. Additionally, accurate NCI computation is quite demanding for first-principles methods, for which a competent machine learning model can be an efficient solution to obtain high NCI accuracy with minimal computational resources. In regard to these aspects, multiple schemes of ensemble learning models (Bagging, Boosting, and Stacking frameworks), are explored in this study. The models are based on various low levels of density functional theory (DFT) calculations for the benchmark databases S66, S22, and X40. All NCIs computed by the DFT calculations can be improved to high-level accuracy (root-mean-square error RMSE = 0.22 kcal/mol in contrast to CCSD(T)/CBS benchmark) by established ensemble learning models. Compared with single machine learning models, ensemble models show better accuracy (RMSE of the best model is further lowered by ∼25%), robustness and goodness-of-fit according to evaluation parameters suggested by the OECD. Among ensemble learning models, heterogeneous Stacking ensemble models show the most valuable application potential. The standardized procedure of constructing learning ensembles has been well utilized on several NCI data sets, and this procedure may also be applicable for other chemical databases.

Antitumor and anti-metastatic mechanisms of Rhizoma paridis saponins in Lewis mice.

Lung cancer is one of the most common causes of death in the world. Rhizoma paridis saponins (RPS) have been found to show inhibition of pulmonary adenoma in previous research. However, the detailed mechanisms of RPS from a holistic view have not been established. In this study, Lewis pulmonary adenoma mice were successfully established to analyze the pathways involved in RPS intervening tumor formation and progression. As a result, RPS inhibited levels of cytokines or receptors such as VEGFD, VEGFR3, RAGE, IL6R, IL17BR, and CXCL16 which were regarded as the initiators induced tumor cell proliferation, adhesion, angiogenesis, and invasion. Meanwhile, RPS raised the content of SOD and CAT enzymes and thereby inhibited the aberrantly active NF-κB, and phosphorylation of PI3K/Akt and MAPK (including p38, Erk1/2, and JNK) signaling pathways. Soon after, RPS changed mRNA expression of nuclear factors containing NF-κB, HIF-1A, STAT3, and Jun, and consequentially suppressed the expression of angiogenesis, lymphangiogenesis, adhesion, inflammation, and invasion enzymes. In conclusion, this research provided a holistic view to understand the multi-target antitumor mechanisms of RPS which promoted the application of RPS in the future.

A cascaded QSAR model for efficient prediction of overall power conversion efficiency of all-organic dye-sensitized solar cells.

A cascaded model is proposed to establish the quantitative structure-activity relationship (QSAR) between the overall power conversion efficiency (PCE) and quantum chemical molecular descriptors of all-organic dye sensitizers. The cascaded model is a two-level network in which the outputs of the first level (JSC, VOC, and FF) are the inputs of the second level, and the ultimate end-point is the overall PCE of dye-sensitized solar cells (DSSCs). The model combines quantum chemical methods and machine learning methods, further including quantum chemical calculations, data division, feature selection, regression, and validation steps. To improve the efficiency of the model and reduce the redundancy and noise of the molecular descriptors, six feature selection methods (multiple linear regression, genetic algorithms, mean impact value, forward selection, backward elimination, and +n-m algorithm) are used with the support vector machine. The best established cascaded model predicts the PCE values of DSSCs with a MAE of 0.57 (%), which is about 10% of the mean value PCE (5.62%). The validation parameters according to the OECD principles are R(2) (0.75), Q(2) (0.77), and Qcv2 (0.76), which demonstrate the great goodness-of-fit, predictivity, and robustness of the model. Additionally, the applicability domain of the cascaded QSAR model is defined for further application. This study demonstrates that the established cascaded model is able to effectively predict the PCE for organic dye sensitizers with very low cost and relatively high accuracy, providing a useful tool for the design of dye sensitizers with high PCE.

Evaluation of New Folate Receptor-mediated Mitoxantrone Targeting Liposomes In Vitro.

Background: Ligand-mediated liposomes targeting folate receptors (FRs) that are overexpressed on the surface of tumor cells may improve drug delivery. However, the properties of liposomes also affect cellular uptake and drug release.

Objective: Mitoxantrone folate targeted liposomes were prepared to increase the enrichment of drugs in tumor cells and improve the therapeutic index of drugs by changing the route of drug administration.

Methods: Liposomes were prepared with optimized formulation, including mitoxantrone folatetargeted small unilamellar liposome (MIT-FSL), mitoxantrone folate-free small unilamellar liposome (MIT-SL), mitoxantrone folate-targeted large unilamellar liposome (MIT-FLL), mitoxantrone folate-free large unilamellar liposomes (MIT-LL). Cells with different levels of folate alpha receptor (FRα) expression were used to study the differences in the enrichment of liposomes, the killing effect on tumor cells, and their ability to overcome multidrug resistance.

The results of the drug release experiment showed that the particle size of liposomes affected their release behavior. Large single-compartment liposomes could hardly be effectively released, while small single-compartment liposomes could be effectively released, MIT-FSL vs MIT-FLL and MIT-SL vs MIT-LL had significant differences in the drug release rate (P<0.0005). Cell uptake experiments results indicated that the ability of liposomes to enter folic acid receptor-expressing tumor cells could be improved after modification of folic acid ligands on the surface of liposomes and it was related to the expression of folate receptors on the cell surface. There were significant differences in cell uptake rates (p<0.0005) for cells with high FRα expression (SPC-A-1 cells), when MIT-FSL vs MIT-SL and MIT-FLL vs MIT-LL. For cells with low FRα expression (MCF-7 cells), their cell uptake rates were still different (p<0.05), but less pronounced than in SPC-A-1 cells. The results of the cell inhibition experiment suggest that MIT-FLL and MIT-LL had no inhibitory effect on cells, MIT-FSL had a significant inhibitory effect on cells and its IC50 value was calculated to be 4502.4 ng/mL, MIT-SL also had an inhibitory effect, and its IC50 value was 25092.1 ng/mL, there was a statistical difference (p<0.05), MIT-FSL had a higher inhibitory rate than MIT-SL at the same drug concentration. Afterward, we did an inhibitory experiment of different MIT-loaded nanoparticles on MCF-7 cells compared to the drug-resistant cells (ADR), Observing the cell growth inhibition curve, both MIT-FSL and MIT-SL can inhibit the growth of MCF-7 and MCF-7/ADR cells. For MCF- 7 cells, at the same concentration, there is little difference between the inhibition rate of MITFSL and MIT-SL, but for MCF-7/ADR, the inhibition rate of MIT-FSL was significantly higher than that of MIT-SL at the same concentration (P<0.05).

Conclusion: By modifying folic acid on the surface of liposomes, tumor cells with high expression of folic acid receptors can be effectively targeted, thereby increasing the enrichment of intracellular drugs and improving efficacy. It can also change the delivery pathway, increase the amount of drug entering resistant tumor cells, and overcome resistance.

Sulfosalicylate mediates improved vinorelbine loading into LUVs and antineoplastic effects.

Liposomal vinorelbine formulation is desirable, as it might improve the therapeutic activity of vinorelbine. However, because of its lipophilic and membrane-permeable properties, vinorelbine is hard to be formulated into liposomes using conventional drug-loading technologies. To improve vinorelbine retention, ammonium salts of several anionic agents were employed to prepare liposomal vinorelbine formulations. It was found that 5-sulfosalicylate (5ssa) could form stable complexes with vinorelbine and stabilize entrapped vinorelbine. The resultant vesicles had an in vitro release t(1/2) of ~12.49 hours in NH(3)-containing media, which is longer than those of sulfate and phytate vesicles (~0.57 hours). The circulation half-life of vinorelbine after the injection of 5ssa vesicles into normal mice was ~13.01 hours, accounting for ~2-fold increase relative to that of sulfate vesicles. Improved drug retention correlated with enhanced antitumor efficacy. In the RM-1/c57 model, 5ssa vesicles were more efficacious than sulfate vesicles (P < 0.05). In RM-1/BDF1 and Lewis lung cancer/c57 models, antitumor efficacy was also considerably improved after vinorelbine encapsulation into 5ssa vesicles. For instance, in the RM/BDF1 model, liposomal vinorelbine was at least 4-fold more therapeutically active than free vinorelbine. Our results demonstrated that 5ssa could stabilize vinorelbine relative to other anions, resulting in the formulation with improved drug retention and efficacy. Improved vinorelbine retention might be associated with the formation of insoluble precipitate, which could be proved by precipitation study and decreased drug-release rate at a high D/L ratio.

The synergistic anticancer effect of formosanin C and polyphyllin VII based on caspase-mediated cleavage of Beclin1 inhibiting autophagy and promoting apoptosis.

OBJECTIVES: Drug combination has a promising and potential development prospect in the treatment of various cancers. The objective of this study is to investigate the synergistic mechanisms of polyphyllin VII (PVII) and formosanin C (FC) in lung cancer. MATERIALS AND METHODS: The combination of FC and PVII influenced on the apoptosis, autophagy, and the relative signalling pathways were analysed in lung cancer cells. RESULTS: The combination of FC and PVII demonstrated a concentration- dependent growth inhibition in human lung cancer cells. The combination index (CI) obtained from four lung cancer cells was smaller than 1. This synergistic antitumour effect was based on the increase of their single proapoptotic effect but inhibiting FC-induced autophagy in NCI-H460 cells. FC and PVII activated proapoptotic elements like cleaved-caspase-3, -8, and -9 to induce Beclin1 cleaved into Beclin1-C which suppressed FC-triggered autophagy and enhanced apoptosis. CONCLUSIONS: Formosanin C and PVII showed a synergistic antitumour effect on lung cancer cells. The findings would provide the foundation for the use of combination drugs in the future.

Diagnostic Accuracy of Interleukin-27 in Bronchoalveolar Lavage Fluids for Pulmonary Tuberculosis.

BACKGROUND: The World Health Organization states that China had 0.9 million cases of tuberculosis in 2017, accounting for 9% of cases globally. Despite a decrease in the incidence and mortality of tuberculosis in China over time, development in choosing the appropriate prevention and control of TB is required. PURPOSE: The aim of this study was to evaluate the diagnostic significance of interleukin-27 in bronchoalveolar lavage fluids for pulmonary tuberculosis. MATERIALS AND METHODS: Eventually, 107 bronchoalveolar lavage fluids from patients were included in this study. The concentrations of interleukin-27 and adenosine deaminase were determined in bronchoalveolar lavage fluids using enzyme-linked immunosorbent assay. RESULTS: It was found that the concentrations of interleukin-27 in bronchoalveolar lavage fluids of sputum-positive pulmonary tuberculosis group were significantly higher than those in sputum-negative pulmonary tuberculosis, lung cancer, and previous pulmonary tuberculosis groups, respectively (all P<0.001). Interleukin-27 levels in bronchoalveolar lavage fluids could be used for diagnostic purpose for pulmonary tuberculosis, with the cutoff value of 7.867 pg/mL; interleukin-27 had a sensitivity of 68.8% and specificity of 100% for the differential diagnosis of pulmonary tuberculosis (sputum-negative and sputum-positive PTB) from lung cancer. And with the cutoff value of 6.012 pg/mL, IL-27 had sensitivity and specificity of both 100% for the differential diagnosis of PTB from previous PTB. The risk of pulmonary tuberculosis was positively associated with the concentrations of interleukin-27 and adenosine deaminase in bronchoalveolar lavage fluids. CONCLUSION: Interleukin-27 in bronchoalveolar lavage fluids is a sensitive and specific biomarker for the differential diagnosis of pulmonary tuberculosis from lung cancer and previous pulmonary tuberculosis.

Encapsulation of mitoxantrone into pegylated SUVs enhances its antineoplastic efficacy.

Mitoxantrone (MIT) was encapsulated into 60, 80 and 100nm pegylated hydrogenated soy phosphatidylcholine/cholesterol (HSPC/chol) vesicles using a transmembrane (NH(4))(2)SO(4) gradient. In-vitro release studies revealed that small-sized formulation had fast drug-release rate. Acute toxicity studies performed in c57 mice proved that all pegylated liposomal MIT (plm) formulations could be well-tolerated at a dose of 9mg/kg, significantly compared to severe toxicity induced by free mitoxantrone (f-M). In KM mice, plm60 was at least 2- to 3-fold less toxic than f-M. After intravenous injection, plm60 was slowly eliminated from plasma relative to f-M, resulting in about 6459-fold increase in AUC and its plasma kinetics exhibited dose dependence. In S-180 bearing KM mice, plm60 preferentially accumulated into tumor zone, with a approximately 12-fold increase in AUC and approximately 10-fold increase in C(max) Furthermore, the accumulation of plm60 in almost all normal tissues markedly decreased. The antitumor efficacy of plm60 was also considerably enhanced. In L1210 ascitic tumor model, plm60 was the most efficacious which led to a approximately 70% long-term survival, significantly compared to 16-33% survival rate in plm80, plm100 and f-M groups at the same dose level (4mg/kg). The antitumor efficacy of plm60 was more encouraging in L1210 liver metastasis model. At a dose of 6mg/kg, approximately 90% animals receiving plm60 treatment could survive 60 days; however, in f-M group at the same dose, all the mice died at approximately 14 days post inoculation. Similarly, plm60 could effectively inhibit the growth of RM-1 tumor in BDF1 mice, resulting in marked increase in tumor doubling time at different dose levels relative to f-M. The improved antineoplastic effects could be ascribed to its small vesicle size, which allowed more drug release after the accumulation into tumor zone. Theoretical considerations revealed that the reduction of vesicle size could increase the specific area of MIT/sulfate precipitate inside the vesicle and the release constant K, which is inversely proportional to vesicle volume (K=pA(m)k(2)k(2)(')/([H(+)](i)(2)V(i))).

Copper ion-mediated liposomal encapsulation of mitoxantrone: the role of anions in drug loading, retention and release.

Besides pH gradient, other transmembrane gradients such as metal ion gradient could be also employed to load drugs into liposomes. In pH gradient method, anions have an important role since they could form specific aggregates with drugs, and then affect drug release kinetics from vesicles. To explore the role of anions in metal ion gradient method, copper ion-mediated mitoxantrone (MIT) loading was investigated systematically. When empty liposomes exhibiting a transmembrane copper ion gradient (300 mM) were mixed with MIT in a molar ratio of 0.2:1, after 5 min incubation at 60 degrees C, >95% MIT could be loaded into vesicles and the encapsulation was stable, regardless of the kinds of anions and initial intraliposomal pH values. The encapsulation ratio decreased with increased MIT/lipid molar ratio. But even when the molar ratio increased to 0.4, >90% encapsulation could still be achieved. In the presence of nigericin and ammonium, the drug loading profiles were affected to different degree with respect to both drug loading rate and encapsulation ratio. Relative to CuSO(4)-containing systems, CuCl(2) mediated MIT loading was unstable. Both nigericin and ammonium could alter the absorption spectra of liposomal MITs loaded with CuSO(4) gradient. In vitro release studies were performed in glucose/histidine buffer and in 50% human plasma using a dialysis method. In both of release media, CuCl(2)-containing vesicles displayed rapid release kinetics in comparison with CuSO(4) systems; and during the experiment period, MIT was lost from the vesicles continuously. When the formulations were injected into BDF1 mice at a dose of 4 mg/kg, all the liposomal formulations exhibited enhanced blood circulation time, with half-life values of 6.8-7.2h, significantly compared to the rapid clearance of free-MIT. In L1210 ascitic model, CuCl(2) formulation was more therapeutically active than CuSO(4) formulation. At a dose of 6 mg/kg, the treatment with CuCl(2) formulation resulted in a median survival time of 21 days, considerably larger than that of CuSO(4) groups (15 days). Based on these data, it was concluded that during the drug loading process, a dynamic transmembrane pH gradient is generated and intraliposomal pH might affect the complexation manner in which Cu(2+) binds MIT. Owing to the presence of pH gradient, after the accumulation within vesicles, a part of MIT will be protonated and precipitated by sulfate. Accordingly, the aggregation status of MIT inside CuSO(4) system was more complicated than that in CuCl(2) vesicles. The difference in physical status of MIT aggregates affects not only the drug release rate, but also their therapeutic effects.

Repeated injection of pegylated liposomal antitumour drugs induces the disappearance of the rapid distribution phase.

Upon repeated administration, empty pegylated liposomes lose their long-circulating characteristics, referred to as the accelerated blood clearance (ABC) phenomenon. To investigate whether cytotoxic drug-containing pegylated liposomes could also elicit a similar phenomenon, two pegylated liposomal antitumour drugs (doxorubicin and mitoxantrone) were prepared, and they were administrated twice in the same animals with a 10-day interval at a dose level of 8 mg kg(-1) (pegylated liposomal doxorubicin) and 4 mg kg(-1) (pegylated liposomal mitoxantrone). By comparing the overall pharmacokinetics after a single-dose injection with that in animals treated with two doses, it was surprising to find that repeated administration of pegylated liposomal antitumour drugs caused the disappearance of rapid distribution phase instead of the ABC phenomenon, resulting in the conversion of a two-compartment model to a one-compartment model. Further investigation revealed that repeated injection induced the decreased uptake of liposomal antitumour drugs by the spleen at the early time point of 0.5-8 h after injection. In contrast, the deposition of liposomal antitumour drugs into liver was not affected. Therefore, the disappearance of the rapid distribution phase might be related to the reduced spleen uptake at the early time point.

Curcumin enhances the anti-cancer effects of Paris Saponin II in lung cancer cells.

OBJECTIVES: To investigate the synergistic mechanisms of Paris Saponin II (PSII) and Curcumin (CUR) in lung cancer. MATERIALS AND METHODS: The combination changed the cellular uptake of CUR and PSII, apoptosis, cell cycle arrest and cytokine levels were analysed on different lung cancer cells. RESULTS: The combination displayed a synergistic anti-cancer effect through promoting the cellular uptake of CUR on different lung cancer cells. Hoechst H33258 staining and FACS assay indicated that the combination of PSII and CUR induced cell cycle arrest and apoptosis. Western blot and cytokine antibody microarray suggested that the combination activated death receptors such as DR6, CD40/CD40L, FasL and TNF-α to induce cancer cells apoptosis, and up-regulated IGFBP-1 leading to inhibition of PI3K/Akt pathway and increase of p21 and p27, which therefore induced a G2 phase arrest in NCI-H446 cells. Meanwhile, the combination suppressed PCNA and NF-κB pathway in 4 kinds of lung cancer cells. They activated the phosphorylation of p38 and JNK, and inhibited PI3K in NCI-H460 and NCI-H446 cells, enhanced the phosphorylation of JNK in NCI-H1299 cells, and increased the phosphorylation of p38 and ERK, and suppressed PI3K in NCI-H520 cells. CONCLUSIONS: PSII combined with CUR had a synergistic anti-cancer effect on lung cancer cells. These findings provided a rationale for using the combination of curcumin and PSII in the treatment of lung cancer in future.

Direct comparison of two pegylated liposomal doxorubicin formulations: is AUC predictive for toxicity and efficacy?

Rationally designed liposomes could improve the therapeutic indexes of chemotherapeutic drugs, which is due to alterations in the pharmacokinetics and biodistribution of encapsulated drugs. For traditional drug delivery systems, the accumulation of drugs in healthy and malignant tissues could be correlated with toxicity and efficacy. Some previous studies also indicate that the higher tumor AUC, the better therapeutic efficacy, suggestive of the possible existence of positive correlation. Are AUC values of liposomal drugs really predictive? For the purpose to address this question, we designed two pegylated liposomal doxorubicin formulations (PLD-75 and PLD-100), which had the same lipid/drug ratio and bilayer composition, but different size and internal ammonium sulfate concentration. In vitro drug retention experiments revealed that drug was released at a faster rate from PLD-75, a small size formulation. The plasma pharmacokinetics of PLD-75 was similar to that of PLD-100, regardless of whether the mice were tumor-free or not. It should be noted, though, that in tumor-bearing mice the plasma doxorubicin level in PLD-75 group was only about 59% of that in PLD-100 group at 48 h post injection. Furthermore, their biodistribution behavior in S-180 tumor-bearing KM mice was significantly different. Compared with animals receiving PLD-100, those receiving PLD-75 showed a 19.2%, 27.8%, and 23.5% decrease in liver (p<0.01), spleen (p<0.001) and lung (p<0.05) AUC, respectively. In other healthy tissues except kidney, the drug deposition also reduced by 10-15%, but the difference was not significant. The tumor AUC after administration of PLD-100 and PLD-75 were 1285.3 ugh/g and 762.0 ugh/g, respectively (p<0.001). Maximum drug levels achieved in the tumors were 33.80 microg/g (for PLD-100) and 20.85 microg/g (for PLD-75), and peak tumor concentration was achieved faster in PLD-75 group. However, enhanced drug accumulation does not mean increased antineoplastic effect, and at the same doxorubicin dose level, PLD-75 was more efficacious. As for toxicity studies, PLD-75 caused more rapid and severe body weight loss despite the fact that drug accumulation in healthy tissues was reduced. Our data indicate that liposomal systems are more complicated than conventional drug delivery systems, and it is hard to predict the toxicity and efficacy of liposomal drugs through the measure of liposomal drug accumulation.

Systemic Perturbations of Key Metabolites in Type 2 Diabetic Rats Treated by Polyphenol Extracts from Litchi chinensis Seeds.

Our previous research obtained Litchi chinensis Sonn. seeds extract (LSE) which showed hypoglycaemic effects on type 2 diabetes (T2D) rats. In order to understand the detailed pathogenesis of diabetes intervened by LSE, the metabonomics strategy was used. As a result, LSE decreased the insulin resistance index and the levels of glucose in urine through elevating the mRNA level of insulin, while decreasing the expression of glucagon to enhance the function of the pancreas. Meanwhile, LSE regulated the glucose and fatty acid metabolisms via increasing the expression of glucose transporter (Glu) 2, Glu4, insulin receptor (IR), and IR substrate-2 (IRS2). LSE effectively restored the impairment of the IRS2/PI3K/Akt/mTOR insulin signaling in the livers. All in all, LSE played a pivotal role in the treatment of T2D through regulation of broad-spectrum metabolic changes and inhibition of the glycogenesis, proteolysis, and lipogenesis in T2D rats.

Freeze-drying of liposomes using tertiary butyl alcohol/water cosolvent systems.

The objective of this study was to obtain dehydrated liposomes using a novel procedure that involves freeze-drying (FD) of liposomes with TBA/water cosolvent systems. The effects of TBA on the integrity/stability of vesicles of HSPC (or SPC):Cholesterol (4:1) were investigated. TBA used as a cosolvent was detrimental to SPC liposomes, leading to increased particle size and leakage of trapped calcein. However, this was not the case for HSPC liposomes. The vesicle size and the retention of trapped calcein after lyophilization from cosolvents were similar to those after FD from water alone. Moreover, the addition of TBA can significantly enhance the sublimation of ice resulting in short FD cycles. The resulting lyophilized cake can form a loose powder upon agitation, which flowed well enough to be easily poured from the vial. Thus FD of HSPC liposomes using TBA/water cosolvent systems can provide sterile powder for specialized applications. In addition, in conjunction with a modified injection method, this FD technology might be used to produce dehydrated HSPC liposomes on a large scale.

Pegylated liposomal mitoxantrone is more therapeutically active than mitoxantrone in L1210 ascitic tumor and exhibits dose-dependent activity saturation effect.

Our previous studies have proved that encapsulation of mitoxantrone into pegylated SUVs (plm60-s) could enhance its antineoplastic efficacy (Li et al., 2008b). However, why plm60-s is more therapeutically active than free mitoxantrone (MIT), and whether pharmacokinetics and activity of plm60-s exhibits dose-dependency are left unknown. In studies with L1210 ascitic tumor-bearing mice in which the dose of MIT was elevated from 2 to 8mg/kg, a saturation of antineoplastic efficacy was observed after plm60-s, and not after free MIT therapy. Total MIT concentrations in plasma, liver and ascitic fluids after plm60-s increased linearly with escalated doses. The released MIT concentrations in ascitic fluid increased continuously before reaching the peak at a dose of 6mg/kg and then decreased. In vitro release experiments using ascitic fluid as release medium revealed that at high concentrations of plm60-s the release of drug was inhibited. At a dose of 4mg/kg, the areas under the curve (AUC) of released MIT in ascitic fluid after plm60-s were higher than those after free MIT, which might be responsible for the enhanced efficacy of plm60-s. These observations may be used to choose a dose regimen of plm60-s to ensure optimal efficacy and to expound the reasons why plm60-s was more therapeutically active.

Direct comparison of two albumin-based paclitaxel-loaded nanoparticle formulations: is the crosslinked version more advantageous?

Nanoparticles using albumin as particle matrix have entered the mainstream of drug delivery. It was reported that non-crosslinked albumin nanoparticles were unstable in circulation and could deliver drugs into tumor through gp60/SPARC pathway; in contrast, the delivery of drugs with stable nanoparticles was dependent on enhanced permeability and retention effect. Thus, it is questionable which kind of nanoparticles was more advantageous. Two versions of albumin-bound paclitaxel nanoparticles were prepared. In vitro, the non-crosslinked particles could rapidly disintegrate and the crosslinked was stable. The pharmacokinetics of both formulations was different especially at early time and the non-crosslinked particles were cleared rapidly. After non-crosslinked particle treatment paclitaxel had a tendency to accumulate into heart and kidney and following therapy with the crosslinked particles, paclitaxel was liable to be delivered into lung, spleen and liver. The delivery efficiency of paclitaxel into tumor following the non-crosslinked particle treatment was greater than that of the crosslinked (p<0.05), thus resulting in a considerably improved antineoplastic activity. Moreover, the non-crosslinked formulation was only slightly more toxic. It was concluded that the non-crosslinked formulation was more advantageous for the delivery of paclitaxel and our conclusion might be generalized to other lipophilic drugs delivered with albumin nanoparticles.

Prolongation of time interval between doses could eliminate accelerated blood clearance phenomenon induced by pegylated liposomal topotecan.

Repeated injection of pegylated liposomes could elicit the disappearance of long-circulating characteristic, referred to as "accelerated blood clearance phenomenon." ABC phenomenon typically occurs when entrapped drugs are not cytotoxic, but recently it was reported that multiple doses of pegylated liposomal topotecan, a cytotoxic drug, could also induce the phenomenon in rats. To reveal whether the phenomenon could be induced in dogs and the effect of time interval between doses on the magnitude of ABC, pLT was repeatedly injected into beagle dogs with a time interval of 7, 21 and 28 days. The anti-PEG Ig M levels were detected using ELISA. It was found that ABC phenomenon could be induced in dogs by pLT. Inter-individual difference in anti-PEG antibody production could be observed, and antibody levels were directly correlated with the magnitude of ABC. Furthermore, time interval between doses had marked effect on the magnitude of ABC phenomenon. When the time interval was prolonged from 1 week to 4 weeks, ABC phenomenon could be eliminated. By comparing the pharmacokinetic profiles of lipid vesicles and entrapped topotecan, it was found that "empty pegylated vesicles" be formed in circulation, which might be responsible for the occurrence of ABC phenomenon.