The enzymatic synthesis of a tetrapeptide Phac-Met-Gly-Trp-Met-OEt, a fragment of the cholecystokinin C-terminal octapeptide CCK-8, was reported. This fragment was synthesized by coupling Phac-Met-OEt with Gly-OMe, Trp-OMe and Met-OEt successively. These three steps were catalyzed by alpha-chymotrpsin, Papain and alpha-chymotrpsin respectively. The results of FAB-MS showed that all the products had the correct molecular mass.
Catalysis ; Chymotrypsin ; *Oligopeptides ; Papain ; Peptide Fragments ; Sincalide/*chemical synthesis

Aim To investigate the specific binding of folate conjugated PGA to FR-positive tumor cells.Method Folate-PGA and PGA were radiolabeled with 125I by the Iodogen method to examine the binding of PGA to FR positive HeLa cells and SKOV3 cells, or FR negative A549 cells. Results 125I-folate-PGA showed specific bound to HeLa cells and SKOV3 cells; Scatchard analysis of the data estimated the Kd of binding to be 0.11 nmol?L-1 and 0.25 nmol?L-1 respectively. 125I-folate-PGA showed virtually little specific binding to A549 cells which lack folate receptors. Conclusions folate-PGA displayed high affinity and good targeting activities for FR-positive tumor cells and the data warranted further studies for enzyme prodrug therapy.

Combination chemotherapy and nanoparticle drug delivery are two promising strategies in cancer treatment. The use of multiple therapeutic agents in combination provides synergistic effects among different drugs against cancer cells and suppresses drug resistance through distinct mechanisms of action.Nanocarriers can improve anti-tumor effects of drugs and reduce systemic toxicity through delivering drugs into the tumor tissue specially. Recently, many studies are aiming to encapsulate multiple agents into nanocarriers to optimize the anti-tumor effects. In the present review, the recent advances of nanoparticle platforms applied with co-delivering two or more drugs were summarized and the various combination strategies based on nanoparticles in oncology were discussed.

The enzymatic synthesis of a tetrapeptide Phac-Met-Gly-Trp-Met-OEt, a fragment of the cholecystokinin C-terminal octapeptide CCK-8, was reported. This fragment was synthesized by coupling Phac-Met-OEt with Gly-OMe, Trp-OMe and Met-OEt successively. These three steps were catalyzed by alpha-chymotrpsin, Papain and alpha-chymotrpsin respectively. The results of FAB-MS showed that all the products had the correct molecular mass.
Catalysis ; Chymotrypsin ; Oligopeptides ; Papain ; Peptide Fragments ; Sincalide ; chemical synthesis

This study aimed to examine the preparation of cationic lipid microbubble (CLM), and evaluate its physical and chemical properties and toxicity, measure the gene transfection efficiency by ultrasound triggered microbobble destruction (UTMD) in combination with CLM. The CLM was prepared by the method of the thin film hydration, and its morphology was observed under the electron microscopy at 1st, 3rd, 7th, 10th, and 14th day after preparation, respectively. The size, Zeta potential and stability of CLM were tested. The acute toxicity of CLM was assessed. The green fluorescent protein gene (EGFP) transfection efficiency was evaluated. The experiment grouping was as follows: naked plasmid group (P group), ultrasonic irradiation plus naked plasmid group (P-US group), naked plasmid plus CLM group (P-CLM group), naked plasmid plus ultrasound and CLM group (UTMD group). The expression of EGFP was detected by fluorescent microscopy and flow cytometry. The results showed that CLMs were spherical in shape, with the similar size and good distribution degree under the light and electron microscopies. The size of CLMs was varied from 250.4±88.3 to 399.0±99.8 nm and the Zeta potential of CLMs from 18.80±4.97 to 20.1±3.1 mV. The EGFP expression was the strongest in the UTMD group, followed by the P-CLM group, P-US group and P group. Flow cytometry results were consistent with those of fluorescent microscopy. The transfection efficiency was substantially increased in the P-US group, P-CLM group and UTMD group as compared with that in the P group, almost 7 times, 10 times and 30 times higher than that in the P group respectively. It is suggested that CLMs prepared by the method of thin film hydration are uniform in diameter, and proved non-toxic. UTMD combined with CLM can significantly increase the transfection efficiency of EGFP to targeted cells.

Objective To prepare a kind of lipid nanoparticle ultrasound contrast agents with the ability to target to viable myocardium for diagnosis . Methods T he agent was a biotinylated ,fluorescent‐labelled ,lipid‐coated , liquid perfluorocarbon emulsion . Physico‐chemical properties of the agent were measured ,including size distribution ,Zeta Potential ,concentration and so on . Ischemia‐reperfusion models were created in rats ,and then exposed to biotinylated anti‐MCP‐1 monoclonal antibody ,rhodamine avidin and biotinylated ,FITC‐labelled nanoparticles ,respectively . Echocardiography was taken before and after injection . Frozen sections of their hearts were observed under fluorescence microscope . Results T he particle diameter ,zeta potential and concentration of lipid nanoparticles were ( 172 .30 ± 52 .06) nm ,( －33 .10 ± 6 .50) mV and ( 2 .28 ± 0 .46 ) × 1011/ml ,respectively . From the short‐axis view ,the myocardium under endocardium of anterior wall was enhanced obviously . While myocardium of other walls were still . T he lipid nanoparticles located in the myocardium of anterior wall and gave out bright green and red fluorescence under fluorescence microscope ,w hile neither lipid nanoparticles nor fluorescence were found in other sites of ventricular myocardium . Conclusions The viable myocardium can be targeted and acoustically enhanced by the self‐made nano‐scale ultrasound contrast agent . T his new agent has potential to improve sensitivity and specificity for noninvasive identifying viable myocardium .

This study aimed to examine the preparation of cationic lipid microbubble (CLM),and evaluate its physical and chemical properties and toxicity,measure the gene transfection efficiency by ultrasound triggered microbobble destruction (UTMD) in combination with CLM.The CLM was prepared by the method of the thin film hydration,and its morphology was observed under the electron microscopy at 1st,3rd,7th,10th,and 14th day after preparation,respectively.The size,Zeta potential and stability of CLM were tested.The acute toxicity of CLM was assessed.The green fluorescent protein gene (EGFP) transfection efficiency was evaluated.The experiment grouping was as follows:naked plasmid group (P group),ultrasonic irradiation plus naked plasmid group (P-US group),naked plasmid plus CLM group (P-CLM group),naked plasmid plus ultrasound and CLM group (UTMD group).The expression of EGFP was detected by fluorescent microscopy and flow cytometry.The results showed that CLMs were spherical in shape,with the similar size and good distribution degree under the light and electron microscopies.The size of CLMs was varied from 250.4±88.3 to 399.0±99.8 nm and the Zeta potential of CLMs from 18.80±4.97 to 20.1 ±3.1 mV.The EGFP expression was the strongest in the UTMD group,followed by the P-CLM group,P-US group and P group.Flow eytometry results were consistent with those of fluorescent microscopy.The transfection efficiency was substantially increased in the P-US group,P-CLM group and UTMD group as compared with that in the P group,almost 7 times,10 times and 30 times higher than that in the P group respectively.It is suggested that CLMs prepared by the method of thin film hydration are uniform in diameter,and proved non-toxic.UTMD combined with CLM can significantly increase the transfection efficiency of EGFP to targeted cells.

Objective To evaluate the regulatory effect of Diwu Yanggan(DWYG)Decoction on lysoglycerophospholipids(Lyso-GPLs)in circulating exosomes in a mouse model of nonalcoholic fatty liver disease(NAFLD).Methods Circulating exosomes isolated from mouse serum by size exclusion chromatography were morphologically characterized using transmission electron microscope and examined for surface markers CD9,CD63 and TSG101 using Western blotting.Twenty-four male Kunming mice were randomized into 3 groups for normal feeding(control,n=8)or high-fat diet feeding for 1 week to induce NAFLD,after which the latter mice were given DWYG decoction(treatment group,n=8)or normal saline(model group,n=8)by gavage for 4 weeks.After the last treatment,blood samples were collected from the mice for testing serum TC,HDL-C,LDL-C,ALT and AST levels and isolating circulating exosomes.Using multivariate statistical analysis based on targeted metabolomics strategy,the potential biomarkers for Lyso-GPLs in the exosomes were screened.Results The isolated exosomes about 100 nm in size had a typical saucer-like structure with distinct double-layer membranes and a mean particle size of 137.5 nm and expressed the specific surface marker proteins CD9,CD63 and TSG101.The mouse models of NAFLD had significantly increased serum levels of TC,HDL-C,LDL-C and AST and lowered serum ALT level.A total of 43 Lyso-GPLs with significant reduction after DWYG Decoction treatment were identified in NAFLD mice.Conclusion DWYG Decoction can regulate Lyso-GPLs in circulating exosomes in NAFLD mice,which provides a new clue for studying the therapeutic mechanism of DWYG Decoction for liver disease.

Objective To evaluate the regulatory effect of Diwu Yanggan(DWYG)Decoction on lysoglycerophospholipids(Lyso-GPLs)in circulating exosomes in a mouse model of nonalcoholic fatty liver disease(NAFLD).Methods Circulating exosomes isolated from mouse serum by size exclusion chromatography were morphologically characterized using transmission electron microscope and examined for surface markers CD9,CD63 and TSG101 using Western blotting.Twenty-four male Kunming mice were randomized into 3 groups for normal feeding(control,n=8)or high-fat diet feeding for 1 week to induce NAFLD,after which the latter mice were given DWYG decoction(treatment group,n=8)or normal saline(model group,n=8)by gavage for 4 weeks.After the last treatment,blood samples were collected from the mice for testing serum TC,HDL-C,LDL-C,ALT and AST levels and isolating circulating exosomes.Using multivariate statistical analysis based on targeted metabolomics strategy,the potential biomarkers for Lyso-GPLs in the exosomes were screened.Results The isolated exosomes about 100 nm in size had a typical saucer-like structure with distinct double-layer membranes and a mean particle size of 137.5 nm and expressed the specific surface marker proteins CD9,CD63 and TSG101.The mouse models of NAFLD had significantly increased serum levels of TC,HDL-C,LDL-C and AST and lowered serum ALT level.A total of 43 Lyso-GPLs with significant reduction after DWYG Decoction treatment were identified in NAFLD mice.Conclusion DWYG Decoction can regulate Lyso-GPLs in circulating exosomes in NAFLD mice,which provides a new clue for studying the therapeutic mechanism of DWYG Decoction for liver disease.

Drug transportation is impeded by various barriers in the hypoxic solid tumor, resulting in compromised anticancer efficacy. Herein, a solid lipid monostearin (MS)-coated CaO2/MnO2 nanocarrier was designed to optimize doxorubicin (DOX) transportation comprehensively for chemotherapy enhancement. The MS shell of nanoparticles could be destroyed selectively by highly-expressed lipase within cancer cells, exposing water-sensitive cores to release DOX and produce O2. After the cancer cell death, the core-exposed nanoparticles could be further liberated and continue to react with water in the tumor extracellular matrix (ECM) and thoroughly release O2 and DOX, which exhibited cytotoxicity to neighboring cells. Small DOX molecules could readily diffuse through ECM, in which the collagen deposition was decreased by O2-mediated hypoxia-inducible factor-1 inhibition, leading to synergistically improved drug penetration. Concurrently, DOX-efflux-associated P-glycoprotein was also inhibited by O2, prolonging drug retention in cancer cells. Overall, the DOX transporting processes from nanoparticles to deep tumor cells including drug release, penetration, and retention were optimized comprehensively, which significantly boosted antitumor benefits.