BMY-28190

Improved strategies for the chemical conversion of natural polymyxin B and colistin to their N-terminal analogs are reported. First, the protection of the side chains of five L-alpha,gamma-diaminobutyric acid (Dab) residues in natural polymyxin B and colistin was achieved with trichloroethoxycarbonyl (Troc), then the resulting pentakis(N gamma-Troc)-polymyxin B and pentakis(N gamma)Troc)-colistin were treated with trifluoroacetic acid (TFA) : methanesulfonic acid (MSA) : dimethylformamide (DMF) : H2O (10 : 30 : 55 : 5) at 40 degrees C in order to remove N alpha-alkanoyl-Dab(Troc)-OH selectively. The new key compounds, tetrakis(N gamma-Troc)-polymyxin B (2-10) and tetrakis(N gamma-Troc)-colistin (2-10), were obtained in 19% and 15% yields, respectively, which is higher than previous reports using trifluoroacetyl (Tfa) for tetrakis(N gamma-Tfa)-polymyxin B (2-10) and tetrakis(N gamma-Tfa)-colistin (2-10), respectively. Acylation of tetrakis(N gamma-Troc)-polymyxin B (2-10) and tetrakis(N gamma-Troc)-colistin (2-10) with various hydrophobic acids bearing aliphatic or aromatic ring structures, followed by the deprotection of Troc by Zn in AcOH, produced polymyxin B (2-10) and colistin (2-10) analogs which were used for structure-activity relationship studies. It was found that cyclohexylbutanoyl-, 4-biphenylacetyl-, and 1-adamantaneacetyl-polymyxin B (2-10) showed potent antimicrobial activity equal to that of polymyxin B against three Gram-negative bacterial strains. The lipopolysacharide (LPS) binding activity of cyclohexylbutanoyl-, 4-biphenylacetyl-, and cyclododecanecarbonyl-polymyxin B (2-10) increased greatly in comparison with that of polymyxin B (2-10). The various N alpha-acylated polymyxin B (2-10) analogs showed slightly higher antimicrobial and LPS binding activities than the corresponding N alpha-acylated colistin (2-10) analogs.

A conventional DC-based immunotherapy has been tested clinically for treatment of patients with advanced cancer but requires modification to further improve the clinical results. In this study, we evaluated the in vivo antitumor effects of DC therapy, non-viral-mediated IL-12 gene therapy, and a combination of the two in a murine bilateral subcutaneous tumor model. DC therapy alone and IL-12 gene therapy alone suppressed tumor growth at the injected sites. However, the antitumor effect on the distant contralateral tumor was insufficient. When DC therapy and IL-12 gene therapy were carried out simultaneously, tumor growth was significantly suppressed bilaterally (P < 0.001). Cytolytic activity was augmented significantly in mice given the combination treatment compared to in mice treated with either DC or IL-12 gene therapy alone (P < 0.05). Microvessel density of both tumors was significantly lower in mice subjected to the combination therapy than in mice treated otherwise (P < 0.05). Furthermore, no side-effects were observed in the treated mice. DC therapy combined with non-viral-mediated intratumoral IL-12 gene delivery has a synergistic antitumor effect not only on targeted tumors but also on contralateral distant tumors and may be of great potential as a therapeutic treatment for patients with advanced cancer.

BMY-28190, an antibiotic complex active against herpes simplex virus type 1 (HSV-1) was produced by the cultured broth of Streptoalloteichus hindustanus sp. nov., a producing strain of tallysomycins A and B. The antibiotic complex was recovered from the broth with Amberlite IRC-50 resin and separated from the coproduced tallysomycins and nebramycins by a series of chromatographies. BMY-28190 exhibited weak inhibitory activity toward Gram-positive and Gram-negative bacteria and strong inhibitory activity toward HSV-1. Structural studies disclosed that BMY-28190 is a novel complex of gamma-poly-D-alpha, gamma-diaminobutyric acids with an average MW of 5,130.