Synthesis and biological activity of 3'-hydroxy-5'-aminobenzoxazinorifamycin derivatives.

As a part of our studies on the syntheses of benzoxazinorifamycin derivatives, 3'-hydroxy-5'-aminobenzoxazinorifamycin derivatives were synthesized, and tested for their antimicrobial activities. The antimicrobial activities of these compounds against gram-positive and gram-negative bacteria were almost identical to those of rifampicin (RFP) and rifabutain (RFB), however, antimicrobial activities against Mycobacterium tuberculosis were superior to RFP, while being similar to RFB. 3'-Hydroxy-5'-(4-alkyl-1-piperazinyl)benzoxazinorifamycin derivatives also had in vitro potent activities against Mycobacterium avium complex (MAC).

Synthesis and biological activity of 5'-aminobenzoxazinorifamycin derivatives.

Benzoxazinorifamycin reacted with various secondary amines to yield various 5'-substituted aminobenzoxazinorifamycin derivatives. The derivatives exhibited potent activities against gram-positive bacteria and mycobacteria. The antimicrobial activities of these compounds against Mycobacterium tuberculosis and Mycobacterium intracellulare were superior to those of rifampicin.

Usefulness of glycosylated recombinant human lymphotoxin for growth inhibition of human and murine solid tumors and experimental metastasis in mice.

We have examined the antitumor and antimetastatic effects of native-type, glycosylated recombinant lymphotoxin (LT) on human and murine tumors transplanted in mice. The results reported here are as follows: (a) The in vivo antitumor spectrum of LT is not coincident with the in vitro study, and it has a wide antitumor spectrum and substantially inhibits the growth of human solid tumors, (b) When both syngeneic and nude mice are transplanted with Meth A tumor, the significant growth-inhibitory effect of LT is obtained in syngeneic mice, but the effect is quite small in nude mice regardless of the routes; LT attains the same degree of effectiveness as that in syngeneic mice, but at an 8 to 16 times higher dose. Furthermore, the pretreatment with anti-asialo-GM1 antibody inhibits the antitumor effects of LT in syngeneic mice, (c) In the pulmonary metastasis model induced by i.

Constitutive high-level production of human lymphotoxin by CHO-K1 cells transformed with the human lymphotoxin gene controlled by a human beta-actin promoter.

To achieve high-level production of human lymphotoxin (hLT), a plasmid (p beta LT-ldhfr) containing the hLT genomic DNA, a mouse dihydrofolate reductase (DHFR) cDNA, and a bacterial Ecogpt gene was cotransfected with a plasmid (p beta LTML) encoding only the hLT genomic DNA into Chinese hamster ovary (CHO-K1) cells at a 1:7 molar ratio. Subsequently one of the Ecogpt-positive clones (clone A31) was grown in stepwise increasing concentrations of methotrexate (MTX). A large amount of the hLT was secreted by cells resistant to increased levels of MTX as a result of coamplification of the DHFR cDNA and the hLT gene.

Comparison of human lymphotoxin gene expression in CHO cells directed by genomic DNA or cDNA sequences.

Four recombinant plasmids coding for human lymphotoxin (LT) were constructed with genomic DNA (gDNA) or cDNA sequences. The simian virus 40 (SV40) early region, which contains the early promoter, an intron of the small-t-antigen-encoding gene, and polyadenylation signal sequences, was used for transcriptional and post-transcriptional regulatory elements in the construction of these plasmids. Two of them contained gDNA and the other two contained cDNA.