streptovaricin-c and Neoplasms

The National Cancer Institute Diversity Set II (1356 compounds) and Diversity Set III (1597 compounds) were screened via in silico methods as potential inhibitors of low molecular weight protein tyrosine phosphatase (LWM-PTP) isoform B (EC 3.1.3.48). Those candidates that demonstrated comparable or better docking scores than that of pyridoxal 5'-phosphate (PLP), one of the most potent known inhibitors of LMW-PTP with a competitive inhibitor dissociation constant (Kis) of 7.6μM (pH 5.0), were analyzed via in vitro kinetic assays against LMW-PTP isoform B. While none of the compounds tested in vitro was significantly better that PLP, five compounds showed comparable inhibition. These five compounds are very diverse in structure and represent new therapeutic leads for inhibition of this isozyme.

Topics: Enzyme Inhibitors; Humans; Molecular Docking Simulation; Neoplasms; Protein Conformation; Protein Isoforms; Protein Tyrosine Phosphatase, Non-Receptor Type 1

The activities of streptovaricin complexes, streptovaricins, streptovals, and streptovarinic degradation products were elevated against RNA-directed DNA polymerases of Rauscher leukemia virus, DNA-dependent DNA polymerase of bacterial and mammalian cells, and DNA-dependent RNA polymerases of mammalian origin. The activities of streptovaricins were also listed for comparison purposes. The effects of streptovaricin complexes on viral DNA polymerases varied significantly from lot to lot, and streptovaricin complex lot 7 was the most active. All the streptovals and streptovaricin degradation products except varicinal A showed a marked improvement (twofold to tenfold) in activity against the viral enzyme over the parent streptovaricins. None of these compounds, however, displayed any significant effect on either the DNA polymerase of L1210 leukemia cells and Escherichia coli or the RNA polymerase of isolated nuclei of mouse liver. As a result of tests in these systems, some specific inhibitors of RNA-directed DNA polymerases of Rauscher leukemia virus were selected.

Topics: Chemical Phenomena; Chemistry; Dactinomycin; DNA-Directed RNA Polymerases; In Vitro Techniques; Neoplasms; Nucleic Acid Synthesis Inhibitors; Rauscher Virus; Reverse Transcriptase Inhibitors; Streptovaricin; Structure-Activity Relationship

Topics: Enzyme Repression; Humans; Interferons; Neoplasms; RNA Viruses; RNA-Directed DNA Polymerase; Streptovaricin; Virus Diseases; Virus Replication

The in vitro susceptibility of murine myeloid colony-forming cells to the antiproliferative activities of three ansamycin antibiotics was determined. These cells were found to be 10- to 40-fold more susceptible than the corresponding human ones.

Topics: Animals; Antibiotics, Antineoplastic; Cells, Cultured; Humans; Mice; Mice, Inbred DBA; Neoplasms; Rifamycins; Streptovaricin

Topics: Antibiotics, Antineoplastic; Antilymphocyte Serum; Antineoplastic Agents; BCG Vaccine; Humans; Immunization, Passive; Immunotherapy; Laser Therapy; Neoplasms; Reverse Transcriptase Inhibitors; Streptovaricin

Topics: Antiviral Agents; Brain; Humans; Interferons; Leukoencephalopathy, Progressive Multifocal; Neoplasms; Oncogenic Viruses; Papillomaviridae; Polyomaviridae; Rifampin; Streptovaricin; Virus Diseases