[Synthesis and antitumor activity of novel tetrahydro-beta-carboline derivatives as KSP inhibitors].

Inhibitors of kinesin spindle protein (KSP) are a promising class of anticancer agents that cause mitotic arrest and induce apoptosis of tumor cells. A series of novel tetrahydro-beta-carboline derivatives were synthesized as kinesin spindle protein inhibitor and evaluated as potential antitumor agents. All compounds showed promising KSP inhibitiory activity. Compounds 8 and 9 exhibited better antitumor activity (Lung/A549, Stomach/AGS) than CK0106023 with GI50/IC50 values (1.07/1.62 and 1.46/3.27 micromol x L(-1), 1.09/>10 and 1.22/6.33 micromol x L(-1), respectively).

CPUYJ039, a newly synthesized benzimidazole-based compound, is proved to be a novel inducer of apoptosis in HCT116 cells with potent KSP inhibitory activity.

OBJECTIVES: This study investigated the antiproliferative and apoptotic activities of CPUYJ039, a newly synthesized benzimidazole-based kinesin spindle protein (KSP) inhibitor, on HCT116 cell lines. METHODS: KSP-inhibitory activity was tested using the malachite-green method. The in-vitro cell proliferation inhibitory activity of the sample was measured using WST reagent. Flow-cytometric evaluation of cellular DNA content was performed. Apoptotic cells were quantified by annexin V-FITC-PI double staining. To confirm that the cytotoxic activity was a consequence of KSP inhibition, microtubule morphology and DNA segregation were observed by double staining of microtubules and DNA. The expression of Bcl-2 and Bax in CPUYJ039-treated HCT116 cells was detected by Western blotting. KEY FINDINGS: CPUYJ039 was evaluated and proved to have potent inhibitory activities in the KSP ATPase and HCT116 cell proliferation assays. CPUYJ039 inhibited the proliferation of HCT116 cells in a dose- and time-dependent manner and markedly induced G2/M phase cell-cycle arrest with characteristic monoastral spindles and subsequent cell death in HCT116 cells, which was associated with an increase of the Bax/Bcl-2 ratio. CONCLUSIONS: These results suggest that CPUYJ039 may be a novel inducer of apoptosis in HCT116 cells with potent KSP inhibitory activity.

De novo design, synthesis and biological evaluation of 1,4-dihydroquinolin-4-ones and 1,2,3,4-tetrahydroquinazolin-4-ones as potent kinesin spindle protein (KSP) inhibitors.

Kinesin spindle protein (KSP) inhibitors are a promising class of anticancer agents that cause mitotic arrest in cells from a failure to form functional bipolar mitotic spindles. Here, we report the design, synthesis and biological evaluation of a novel series of 1,4-dihydroquinolin-4-ones and 1,2,3,4-tetrahydroquinazolin-4-ones using de novo design method. The synthesized compound was evaluated and proved to have potent inhibitory activities in the KSP ATPase. Compounds 15j and 15p show potent inhibitory activities in cell proliferation assays. Preferred compound 15j markedly induced G2/M phase cell cycle arrest with characteristic monoastral spindles and subsequent cell death in A549 cells. In vivo evaluation of 15j on the growth of transplantable S180 sarcoma in mice suggested its therapeutic potential for further development.

Design, synthesis and bioevaluation of dihydropyrazolo[3,4-b]pyridine and benzo[4,5]imidazo[1,2-a]pyrimidine compounds as dual KSP and Aurora-A kinase inhibitors for anti-cancer agents.

Four series of dihydropyrazolo[3,4-b]pyridines and benzo[4,5]imidazo[1,2-a]pyrimidines were designed and synthesized as dual KSP and Aurora-A kinase inhibitors for anti-cancer agents by introducing some fragments of Aurora-A kinase inhibitors into our KSP inhibitor CPUYL064. A total of 19 target compounds were evaluated by two related enzyme inhibition assays and a cytotoxicity assay in vitro. The results showed that some target compounds could inhibit both enzymes, and several of them showed significant inhibition activity against HCT116 cell line. Despite showing moderate KSP and Aurora-A kinase inhibition, the lead compounds 6a and 6e displayed significant cytotoxic activity in the micromolar range, especially against the HCT116 cell line and HepG2 cell line. The results may be useful for developing a new class of inhibitors having a dual function, KSP inhibition and Aurora-A kinase inhibition, for the treatment of cancer.

Discovery of tetrahydro-beta-carbolines as inhibitors of the mitotic kinesin KSP.

Inhibitors of kinesin spindle protein (KSP) are a promising class of anticancer agents that cause mitotic arrest in cells from a failure to form functional bipolar mitotic spindles. Here, we report the synthesis and biological evaluation of a novel series of tetrahydro-beta-carboline analogs based on the structure of the known KSP inhibitor HR22C16. Preferred compounds 11b, 12a and 19b were identified as potent inhibitors in a KSP ATPase assay with good anti-proliferative activity in A549 cells.

A novel anti-platelet aggregation tripeptide from Agkistrodon acutus venom: isolation and characterization.

AAP, a tripeptide that inhibited rabbit platelet aggregation, was isolated from Agkistrodon acutus venom by ion-exchange, gel filtration and reverse-phase chromatography. Amino acid sequences which determined mainly by amino acid analyses and NMR spectroscopy indicated it was a tripeptide including pyroglutamic acid, asparagine and tryptophane residues. The ESMS experiment assigned a molecular weight of 429 Da. AAP inhibited rabbit platelet aggregation induced by ADP, PAF-acether, collagen and thrombin, the IC(50)s were 178 microM, 332 microM, 179 microM and 203 microM, respectively. AAP also inhibited thrombus formation in vivo thrombosis model and prevented the combination between fibrinogen and GP IIb/IIIa. Besides, AAP was not toxic after intravenous injection into mice at a higher dose. Those studies might be helpful to delineate unknown mechanisms involved in platelet aggregation and serve as a model for developing antithrombotic agents.

Intracellular GSH and ROS levels may be related to galactose-mediated human lens epithelial cell apoptosis: role of recombinant hirudin variant III.

Oxidative processes in the lenses are the most commonly found damaging factor for the development of cataracts. Hirudin, a most potent inhibitor of thrombin as an antithrombic drug, also have potential use in cataracts. In order to investigate the mechanisms of hirudin against galactose-induced cataract at the cellular level. We used recombinant hirudin variant III (rHV3) to study the protective effect of hirudin on galactose-mediated human lens epithelial cells injury. The human lens epithelial cells (hLECs) were cultured in D/F(12)-10% FBS medium containing 125 mM D-galactose with or without rHV3. Cell viability was assessed by methylthiazol tetrazolium (MTT) assay and propidium iodide (PI) staining in situ. Cell apoptosis was elevated with comet assay (single cell gel electrophoresis, SCGE), AO/EB double staining and Annexin-V/PI double staining assay. Reactive oxygen species (ROS) were quantified with 2',7'-dichlorofluorescein (DCF), and free glutathione (GSH) levels were measured with a commercial GSH quantification kit. Decreased viability and increased apoptosis of the hLECs were observed when incubated with 125 mM galactose. These hLECs also demonstrated the increased presence of ROS, whereas GSH was reduced. rHV3 blocked the induction of cell death, apoptosis and oxidative stress in hLECs. One mechanism may be through regulating intracellular ROS and GSH levels to inhibit apoptosis of the human lens epithelial cells.

[Synthesis and biological evaluation of tetrahydro-beta-carline derivatives].

Kinesin spindle protein (KSP/Eg5) is essential for the formation and maintenance of bipolar spindles during mitosis. Inhibition of this protein leads to cell cycle arrest and apoptosis without interfering other microtubule-dependent processes. Therefore, it is a potential target in cancer therapy. Here, a series of tetrahydro-beta-carboline derivatives 5a - k were synthesized as kinesin spindle protein inhibitor. Their structures were confirmed with 1H NMR, ESI-MS and elemental analysis. The synthesized compounds were evaluated for their inhibition of KSP.

[Primary structure determination of hirudin and reteplase fusion protein by LC/ESI-MS/MS spectrometry].

The aim is to determine the primary structure of a new hirudin and reteplase fusion protein (HV12p-rPA) by LC-ESI-MS/MS spectrometry. The molecular weight of the hirudin and reteplase fusion protein (HV12p-rPA) was measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The HV12p-rPA was digested with trypsin and chymotrypsin separately and the peptides in the digest mixtures were identified by LC-ESI-MS/MS. The molecular weight of HV12p-rPA was 41,472 Da, which was in accordance with the theoretical value. The peptide fragments of HV12p-rPA digested with trypsin were identified by LC-ESI-MS/MS spectrometry and the results indicated that the fusion protein contained r-PA. Then, the peptides of HV12p-rPA digested with chymotrypsin were identified by the same method. The results indicated that the fusion protein contained HV12p and the linker-containing peptide, DEGGGSY. MASDF and LDWIRDNMRP were identified as the N-terminal and C-terminal containing peptides in the chymotryptic digest mixture of the fusion protein. All of the Xcorr values exceeded 1.5, some of which were above 3.0, showing that the results were correct and credible and a sequence coverage of 85% was achieved. HPLC/MS analysis coupled with uncompleted digestion indicated that all these peptides were arranged with the correct order as expected. Thus, sequence of the fusion protein was confirmed and it was consistent with our design in upstream construction.

Cloning, enzyme characterization of recombinant human Eg5 and the development of a new inhibitor.

The microtubule-dependent motor protein Eg5 is essential for the development and function of the mitotic spindle. Now it has become an anti-mitotic drug target in high throughput screening for anticancer dugs in vitro. Here is a protocol for cloning, expression and purification of a human Eg5 that codes for motor and linker domain in Escherichia coli BL21 (DE3) cells. The effects of temperature, pH, metal ions and DMSO on ATPase activity were investigated. A new compound CPUYL064 showed good inhibitory effect against Eg5 (IC(50) value, 100 nM). It inhibited the proliferation of human hepatocellular liver carcinoma cell line HepG2 in a dose- and time-dependent manner. CPUYL064 induced a clear G(2)/M phase arrest and caused the monastral spindle in HepG2 cells. Induction of apoptosis was further confirmed by changes in membrane phospholipids, changes in mitochondrial membrane potential and by detection of DNA fragmentation. These results indicate that CPUYL064 could be developed as a new, potent mitotic arrest compound.

Enhanced anti-tumor effects achieved in a murine tumor model using combination therapy of recombinant human manganese superoxide dismutase and adriamycin.

Manganese superoxide dismutase (MnSOD) is the only primary antioxidant enzyme in mitochondria that scavenges superoxide radicals. Overexpressing MnSOD in cancer cells by cDNA transfection suppresses tumor formation and reverses malignant growth. In this study, we examined the effect of recombinant human manganese superoxide dismutase (rhMnSOD) alone and in combination with adriamycin (ADR) against solid tumors of sarcoma 180 in Institute of Cancer Research (ICR) mice. Administration of rhMnSOD alone and in combination with ADR significantly inhibited tumor growth in a dose-dependent manner. The use of rhMnSOD in combination with ADR enhanced ADR's anti-tumor potency without increasing toxicity. Histopathological examination provided evidence of the anti-tumor effect. In addition, we found lymphocyte infiltration of the tumors, with an increase in both CD4- and CD8-positive cells in the treated tumors. The expression of CD4 and CD8 was up-regulated with increasing dose of rhMnSOD, and the combination treatment with ADR further enhanced this up-regulation. Collectively, these data indicate that rhMnSOD may exhibit an anti-tumor effect by stimulating the immune system and promoting the recruitment of lymphocytes into the tumor to kill tumor cells. Thus MnSOD may constitute a potential new therapeutic agent to be exploited as an adjuvant in cancer therapy.

Potential use of hirudin in diabetic cataract: a study of galactose mediated human lens epithelial cells injury.

Osmotic stress, together with weakened antioxidant defense mechanisms, is attributed to the changes observed in human diabetic cataract. The use of hirudin, an antithrombic agent, in the pathogenesis of human cataracts has not been studied so far. Since the epithelium is the metabolic unit of the lens, the effect of recombinant hirudin variant III (rHV3) on galactose-induced morphological changes and antioxidant status of human lens epithelial line SRA01/04 in culture was evaluated in this study. The human lens epithelial cells (hLECs) were cultured in D/F(12) medium (normal group), D/F(12) medium + 50 mM D-galactose (control group) or D/F(12) medium + 50 mM D-galactose+rHV3 (test group) for 24 or 72 h. The cells were observed under the light, fluorescence and transmission electron microscope for any morphological changes, while the cell viability was assessed by methylthiazol tetrazolium (MTT) assay. The cells in flasks were harvested for the estimation of various antioxidant parameters. Cell morphology, viability, malondialdeyde, glutathione and antioxidant enzymes were significantly altered in the control group as compared with the normal group. Administration of rHV3 confers significant protection against these changes in the human lens epithelial cells. These results demonstrated that rHV3 could effectively protect galactose-induced hLEC injury and suggested that it could have potential use in diabetic cataracts.

[Application of HPLC-ESI-ITMS in the quality control of carboxyterminal sequence confirmation for insulin and insulin chain B].

Application of HPLC-ESI-ITMS in the quality control of carboxyterminal sequence confirmation for insulin and insulin chain B was studied. The solution of intact insulin or insulin chain B was added to the solution of carboxypeptidase P (CPP) and carboxypeptidase Y (CPY). Fractions of appropriate volume were removed at some appointed time points, acidified with the same amount of 1% formic acid to stop the digestion, and then briefly vortexed for HPLC-ESI-ITMS analysis. Mobile phase A consisted of 0.02% TFA in 98% ultra-pure water and 2% acetonitrile. Mobile phase B consisted of 0.02% TFA in 98% acetonitrile and 2% ultra-pure water. The solution used for post-column fix consisted of propionic acid and isopropyl alcohol (20 : 80, v/v). Chromatographic separation was carried out on a reversed-phase column (Zorbax Prosphere C18, 300A, 5 microm, 2.1 mm ID x 150 mm length). The molecular weights of the multiply charged ions representing consecutive truncated losses of carboxyterminal amino acids were determined by the use of HPLC-ESI-ITMS. The differences between the consecutive truncated peptides are the experimental weights of the carboxyterminal amino acid residues. The carboxyterminal amino acid residue Ala, which released from chain B of intact insulin, was confirmed in the nanomolar concentration range by analyzing the molecular weight of the truncated peptides. Another one carboxyterminal amino acid Ala was confirmed in the nanomolar concentration range of insulin chain B. In the quality control for recombinant DNA product or natural protein, the confirmation of 1 - 3 carboxyterminal amino acid residues is regarded to be up to standard. One amino acid residue of insulin or insulin chain B could be confirmed accurately in the nanomolar concentration range. The results showed that intact insulin could be directly sequenced in the quality control without separating chain B from chain A. There would be no need to separate chain A from chain B to identify carboxyterminal of intact insulin. Furthermore, the method saved us a lot of trouble from the preparation and purification of insulin chain A and chain B.

Study on hepatoprotective effect of peptide S-8300 from shark liver.

AIM: To explore the effects of peptide S-8300 from shark liver (S-8300) on liver function as well as in regulating immune functions in experimental injury models. METHODS: Mice were administered with different doses of S-8300 for four consecutive days, followed by mice injected with tetrachloromethane (CCl(4)) on d 3. The activity of ALT, AST, LDH, SOD and contents of MDA and GSH in the mice liver were tested. And mice were treated with Cy (100 mg/kg) at the beginning of the experiment to induce immunosuppression model. The S-8300 groups were treated with S-8300 seven days after the beginning of Cy administration. The effects of S-8300 on the formulation of serum hemolysin and the content of IL-2 in serum in the immunosuppression mice were observed. RESULTS: S-8300 obviously decreased the level of ALT (52.2+/-11.0 U/dL vs 135.9+/-6.5 U/dL, P<0.01), AST (67.5+/-6.9 U/dL vs 238.8+/-8.7 U/dL, P<0.01), LDH (155.1+/-46.8 U/dL vs 240.4+/-6.0 U/dL, P<0.01) and MDA (0.64+/-0.027 nmol/mg vs 1.06+/-0.040 nmol/mg, P<0.01) and increased SOD (24.51+/-1.01 U/mg vs 19.05+/-0.73 U/mg, P<0.01) and GSH (24.17+/-0.91 microg/mg vs 14.93+/-0.45 microg/mg, P<0.01) in mice liver damaged by CCl(4). S-8300 also markedly improved the formulation of serum hemolysin (0.094+/-0.005 A(540) vs 0.063+/-0.006 A(540), P<0.01) and increased the level of IL-2 (9.74+/-1.16 pg/mL vs 5.81+/-0.87 pg/mL, P<0.01) in serum of the immunosuppression mice. CONCLUSION: The results suggested S-8300 has significant hepatoprotective, immunomodulatory and inhibiting of lipid peroxidation activity.

[Preliminary studies on in vitro and in vivo thrombolytic activities of thrombolytic enzyme from an induced Bacillus subtilis strain].

OBJECTIVE: To separate and purify a novel thrombolytic enzyme (FSC2-13) from culture media of an induced Bacillus subtilis strain and to study its in vitro and in vivo thrombolytic activities. METHODS: Employed fibrin plate method, pyrogenation (heating up) fibrin plate method and SDS-PAGE were used respectively to study FSC2-13 hydrolyzing fibrin and fibrinogen in vitro. Investigations were made on its in vivo pharmacodynamics using rat thrombogenesis inhibition model after it was administrated by intestinal route. RESULTS: FSC2-13 could hydrolyze fibrin and fibrinogen in vitro and had hydrolysis sites on three peptide chains of fibrinogen. FSC2-13 could significantly inhibit the formation of rat venous thrombus after being administrated by intestinal route. Thrombogenesis inhibition rate was 68%. Activated partial thromboplastin time increased by 51%, fibrinogen content decreased by 49%, fibrin degradation product (FDP) content also increased obviously, but the plasminogen content did not change obviously. CONCLUSION: FSC2-13 possessed in vitro and in vivo thrombolytic activities in a special way. There seem to be prospects for researches to develop it into a new generation of oral thrombolytic drug.

[Protective effects of shark hepatic stimulator substance against acute hepatic injury induced by acetaminophen in mice].

AIM: To investigate the protective effects of shark hepatic stimulator substance (sHSS) against acute hepatic injury induced by acetaminophen (AAP) in mice. METHODS: Acute hepatic injury model of Balb/c mice was induced by a single intraperitoneal injection of AAP (200 mg.kg-1, i.p.). Serum ALT and AST activities were analyzed. The changes of microstructure and ultrastructure of hepatocyte were observed under optical and electronic microscope. The hepatocyte apoptosis was analyzed by flow cytometer and the expression level of Fas mRNA was determined by RT-PCR. RESULTS: The activities of serum ALT and AST were significantly decreased and both necrosis and inflammatory infiltration were improved in the mice treated with sHSS 3.0 and 1.5 mg.kg-1. sHSS (3.0 mg.kg-1) prevented the ultrastructural changes of hepatocytes caused by AAP, decreased the percentage of apoptotic cells, and downregulated the expression level of Fas mRNA. CONCLUSION: sHSS protected hepatocytes from AAP-induced injury, which might be associated with its protection of the mitochondria and inhibition of apoptosis and expression of Fas mRNA in hepatocytes.

[Antibody sandwich enzyme-linked immunoadsorbent assay for determination of recombinant E. coli L-asparaginase in rat plasma and its pharmacokinetics].

AIM: To establish antibody sandwich enzyme-linked immunoadsorbent assay for determination of recombinant E. coli L-asparaginase in rat plasma and study its pharmacokinetics. METHODS: A Japanese white rabbit was immunized with recombinant E. coli L-asparaginase. Immunoglobulin G was separated and purified by using DEAE-cellulose chromatography. Conjugation of horseradish peroxidase to immunoglobulin G was obtained using the two-step glutaraldehyde method. Recombinant E. coli L-asparaginase protein in plasma was measured by antibody sandwich enzyme-linked immunoadsorbent assay. Pharmacokinetic parameters were assessed with model-dependent method. RESULTS: The linearities was 1-64 U.L-1. Concentration-time profile after i.v. of 1.25, 2.50, 5.00 kU.kg-1 of recombinant E. coli L-asparaginase fitted with a two-compartment model. The first and terminal elimination T1/2 were 0.50-0.57 h and 2.45-3.02 h, respectively. The AUC was linearly related to the doses. CONCLUSION: Antibody sandwich enzyme-linked immunoadsorbent assay was constant, reliable, sensitive, and suitable for the determination of recombinant L-asparaginase. Pharmacokinetics of recombinant E. coli L-asparaginase in rats is warranted for the design of future clinical trails.