HIV-1 fusion inhibitors are a new class of anti-HIV compounds, which block the entry of HIV into target cells through preventing the fusion between viral and cell plasma membrane and thus interrupt the initial steps of viral replication. T-20 (enfuvirtide), which has been clinically approved as the first fusion inhibitor of HIV-1 by U.S. FDA in 2003, can suppress replication of HIV variants with multi-drug resistance to reverse transcriptase and protease inhibitors. Peptides and small molecules display potent anti-HIV fusion activities by targeting gp41 thus inhibit its fusogenic function. In recent years, with the development of studies on the molecular mechanism of HIV membrane fusion process and the function of gp41, many new fusion inhibitors are found and some have been in advanced clinical trials. This review discusses recent progress in the development of HIV-1 fusion inhibitors targeting the gp41.
Anti-HIV Agents ; chemical synthesis ; chemistry ; pharmacology ; Drug Resistance, Multiple ; HIV Envelope Protein gp41 ; chemical synthesis ; chemistry ; pharmacology ; HIV Fusion Inhibitors ; chemical synthesis ; chemistry ; pharmacology ; HIV Infections ; drug therapy ; HIV-1 ; drug effects ; physiology ; Humans ; Peptide Fragments ; chemical synthesis ; chemistry ; pharmacology ; Peptides ; chemical synthesis ; chemistry ; pharmacology ; Recombinant Fusion Proteins ; chemical synthesis ; chemistry ; pharmacology ; Virus Replication ; drug effects ; alpha 1-Antitrypsin ; chemical synthesis ; chemistry ; pharmacology

A humanized monoclonal antibody against HER2 has been using in a clinical setting and has been shown to possess therapeutic properties. A mimetic peptide against HER2 was also reported to bind to the HER2 receptor with some therapeutic potential. Based on a previous report and the sequence of Herceptin, we designed oligonucleotides of anti-HER2 mimetic peptides, named V2 and V3 peptides, in order to develop a peptide- producing vector system for biologic therapy against HER2- overexpressing cancers. We also adopted the sequence of a previously reported mimetic peptide, V1 (Park BW et al. Nat. Biotechnol, 2000, 18: 194-198), as a reference peptide. We examined the effects of the V2 and V3 peptides against the HER2-overexpressing cell lines, SK-BR-3 and T6-17. Transient transfection of the construct expressing V1 and V2 inhibited cell proliferation in HER2-overexpressing cell lines by 20 - 30%, but had no effect on the HER2-negative NIH3T3 cells. The proliferation inhibition shown by V2 was slightly better than that shown by V1. Recombinant peptides V2 and V3 were produced on a large scale in an E. coli system, and the V2 peptide showed anti-HER2-specific tumor cell proliferation inhibition of 10% to 30%. Current results suggest that anti-HER2 mimetic peptides, overexpressed by a constitutive promoter or produced in an E. coli system, could specifically inhibit the proliferation of HER2-expressing cancer cells. Further efforts to augment the biologic specificity and efficacy and to develop new technologies for the purification of the peptide from the E coli system are needed.
Amino Acid Sequence ; Animals ; Cell Division/drug effects ; Cell Line ; Mice ; Oligopeptides/chemical synthesis/pharmacology ; Peptide Fragments/*chemical synthesis/*pharmacology ; Receptor, erbB-2/*chemistry ; Recombinant Proteins/chemical synthesis/pharmacology ; Support, Non-U.S. Gov't ; *Technology, Pharmaceutical ; Transfection

OBJECTIVELidamycin (LDM) can be dissociated to an apoprotein (LDP) and an active enediyne chromophore (AE). The detached AE can reassemble with its LDP-containing fusion protein to endow the latter with potent antitumor activity. However, the reassembly of AE with LDP is affected by several factors. Our aim was to optimize the assembly efficiency of the AE with a LDP-containing fusion protein and investigate the influence of several factors on the assembly efficacy.

METHODSA method based on RP-HPLC was developed to analyze the assembly rate, and an orthogonal experimental design L(9) (3(4)) was used to investigate the effects of temperature, assembly time, pH and molecular ratio of LDP-containing fusion protein to AE on the assembly rate. Furthermore, the determined optimum conditions for the assembly rate of the LDP-containing fusion protein with AE were applied and evaluated.

RESULTSA calibration curve based on the LDM micromolar concentration against the peak-area of AE by HPLC was obtained. The order in which individual factors in the orthogonal experiment affected the assembly rate were temperature>time>pH>molar ratio of AE to protein and all were statistically significant (P<0.01). The optimal assembly conditions were temperature at 10°C, time of 12 h, pH 7.0, and the molar ratio of AE: protein of 5:1. The assembly rate of AE with a LDP-containing fusion protein was improved by 23% after condition optimization.

CONCLUSIONThe assembly rate of chromophore of lidamycin with its LDP-containing fusion protein was improved after condition optimization by orthogonal design, and the optimal conditions described herein should prove useful for the development of this type of LDP-containing fusion protein.

Aminoglycosides ; administration & dosage ; chemical synthesis ; chemistry ; pharmacology ; Antibiotics, Antineoplastic ; administration & dosage ; chemical synthesis ; chemistry ; pharmacology ; Apoproteins ; chemistry ; Cell Line, Tumor ; Cell Survival ; Chromatography, High Pressure Liquid ; Drug Design ; Enediynes ; administration & dosage ; chemical synthesis ; chemistry ; pharmacology ; Humans ; Recombinant Fusion Proteins ; chemistry ; Single-Chain Antibodies ; chemistry

OBJECTIVETo study the inhibition of maxizyme (Mz) directed against the mutant-type p53 gene (mtp53) at codon 249 in exon 7 (AGG --> AGT) both in cell-free system and in MHCC97 cell lines.

METHODSMaxizyme and control mutant maxizyme (G5 --> A5) were designed by computer and cloned into the eukaryotic expression vector pBSKneoU6 (pU6Mz, pU6asMz). Mz was driven by T7 RNA polymerase promoter in vitro. In the cell lines, U6 promoter was driven by RNA PolIII. The mutant type p53 gene fragment was cloned into the pGEM-T vector under the T7 promoter control. The 32P-labeled mtp53 transcript was the target RNA. Cold maxizyme transcripts were incubated with 32P-labeled target RNA in vitro. pU6Mz was introduced into MHCC97 cells by Lipofectamine2000 and mtp53 expression was analyzed by RT-PCR and Western blot.

RESULTSIn vitro cleavage showed that pU6Mz was very active with cleavage efficiency of 42% while pU6asMz was not. The wild type p53 was not cleaved. Partial down-regulation of mtp53 mRNA and mtp53 protein were observed in MHCC97 cells transfected with pU6Mz but not those with pU6asMz. The proliferation of MHCC cells was inhibited by MTT analysis.

CONCLUSIONOur findings suggest that the chimeric U6 maxizyme against the mtp53 is a new promising gene therapeutic agent in treating hepatocellular carcinoma.

Carcinoma, Hepatocellular ; genetics ; Cell Line, Tumor ; Genetic Therapy ; methods ; Genetic Vectors ; Humans ; Liver Neoplasms ; genetics ; Nucleic Acid Conformation ; Point Mutation ; Protein Conformation ; RNA, Catalytic ; RNA, Messenger ; chemical synthesis ; metabolism ; Recombinant Fusion Proteins ; Ribonuclease T1 ; pharmacology ; Tumor Suppressor Protein p53 ; genetics

Many antineoplastic agents can cause myelosuppression and thrombocytopenia. Thrombopoietin (TPO) is believed to be the major cytokine affecting the proliferation and maturation of megakaryocytes and increasing circulating platelet levels. We have designed and synthesized a TPO mimetic peptide, it can increase circulating platelet levels in vivo. For increasing half-life and forming dimer, the peptide was expressed as chimeric proteins with human IgG1 Fc fragments. The cDNA of TPO mimetic peptide was synthesized chemically and linked respectively to 5' terminus of human IgG1 Fc cDNA fragments in various length (Fc1: Fc 5' 648 bp; Fc2: Fc 5' 270 bp; Fc3: Fc 5' 267 bp; Fc4: Fc 5' 90 bp), and cloned into expression plasmid pET28a (+) for constructing four recombinant plasmids. By transforming the four recombinant plasmids into E. coli. BL21 (DE3) respectively, we got 3 kinds of engineered E. coli which express TPO + Fc chimeric proteins(28 kD TPO + Fc1, 12 kD TPO + Fc2 and 12 kD TPO + Fc3) at high level respectively, the expressed proteins were purified with DEAE-Sepharose FF and S-Sepharose FF column. The bioactivities of the expressed chimeric proteins(TPO + Fc1, TPO + Fc2 and TPO + Fc3), TPO mimetic peptide, and PEG4000 coupled TPO mimetic peptide were evaluated with Ba/F3-mp1 in vitro and with carboplatin-induced thrombocytopenia mice in vivo, the expressed chimeric proteins have higher activity than TPO mimetic peptide both in vitro and in vivo, the EC50 on Ba/F3-mp1 cells were 13, 10, 10, 50, and 25 nmol/L respectively, all of them can increase circulating platelet counts. Their imol/Lunogenicity were valuated in mice, none of them can elicit mice to produce antibodies to TPO mimetic peptide, meanwhile three TPO + Fc chimeric proteins can elicit mice to produce antibodies to human IgG1 Fc. These studies have laid basis for production of TPO mimetic peptide by genetic engineering.
Animals ; Base Sequence ; Blood Platelets ; drug effects ; Cell Division ; drug effects ; Female ; Humans ; Immunoglobulin Fc Fragments ; genetics ; immunology ; pharmacology ; Immunoglobulin G ; genetics ; Male ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Oligopeptides ; chemical synthesis ; genetics ; pharmacology ; Recombinant Fusion Proteins ; genetics ; immunology ; pharmacology ; Thrombocytopenia ; blood ; immunology ; Thrombopoietin ; genetics ; immunology ; pharmacology