Synthesis of potent and selective inhibitors of Candida albicans N-myristoyltransferase based on the benzothiazole structure.

Two parallel synthetic methods using solid-supported reagents were established to examine the rapid optimization of weak hit compound 1. Several compounds showed high potency in the low nanomolar range against N-myristoyltransferase. The structure-activity relationship (SAR) and antifungal activities of a series of novel 2-aminobenzothiazole N-myristoyltransferase inhibitors are presented.

A potential therapeutic role for small nonpeptidyl compounds that mimic human granulocyte colony-stimulating factor.

Granulocyte colony-stimulating factor (G-CSF) stimulates the proliferation of bone marrow granulocytic progenitor cells and promotes their differentiation into granulocytes. G-CSF is therefore an important component of immune defense against pathogenic microorganisms: recombinant human G-CSF (rhG-CSF) is used to treat patients with a variety of neutropenias. In the present study, we screened approximately 10 000 small nonpeptidyl compounds and found 3 small compounds that mimic G-CSF in several in vitro and in vivo assays. These compounds induced G-CSF-dependent proliferation, but had no effect on interleukin-3-dependent, interleukin-2-dependent, interleukin-10-dependent, thrombopoietin (TPO)-dependent, or erythropoietin (EPO)-dependent proliferation. Each compound induced the phosphorylation of signal transducers and activators of transcription-3 (STAT3) and mitogen-activated protein kinase (MAPK) in a G-CSF-dependent cell line and in human neutrophils. In addition, these compounds induced hematopoietic colony formation from primary rat bone marrow cells in vitro. When subcutaneously injected into normal rats, they caused an increase in peripheral blood neutrophil counts. Furthermore, when they were administered to cyclophosphamide-induced neutropenic rats, blood neutrophil levels increased and remained elevated up to day 8. We therefore suggest that these small nonpeptidyl compounds mimic the activity of G-CSF and may be useful in the treatment of neutropenic patients.

A mutated superantigen SEA D227A fusion diabody specific to MUC1 and CD3 in targeted cancer immunotherapy for bile duct carcinoma.

In cancer immunotherapy research, many bispecific antibodies (BsAbs) have been developed for directing T cells toward tumor cells. Recent advances in genetic engineering have made it possible to prepare immunoglobulin fragments consisting of variable domains using bacterial expression systems. Therefore, recombinant BsAbs, termed diabodies, have attracted particular attention. We have previously produced an anti-MUC1 x anti-CD3 diabody (Mx3 diabody) in an Escherichia coli ( E. coli) expression system. In order to reinforce the antitumor effects of the Mx3 diabody, mutated superantigen staphylococcal enterotoxin A (SEA) D227A was genetically fused to the Mx3 diabody. The SEA D227A fusion Mx3 diabody (SEA D227A-Mx3 diabody) thus constructed showed remarkable MUC1-specific antitumor effects when used with effector cells (lymphokine-activated killer cells with T-cell phenotype [T-LAK] and peripheral blood mononuclear cells [PBMCs]). In the bile duct carcinoma (BDC)-xenografted severe combined immunodeficient (SCID) mouse model, it also demonstrated strong antitumor activity when administered i.v. together with T-LAK cells and interleukin-2 (IL-2). In this experiment, the complete disappearance of tumors was observed in 3 out of 6 mice, and the other 3 showed marked retardation of tumor growth. Therefore, the SEA D227A-Mx3 diabody is considered to be a promising reagent in specific targeted immunotherapy for BDC and other MUC1-positive carcinomas. This is the first report on a diabody that is effective in treating human solid cancers in the xenografted SCID mouse experimental model.