The specific inhibition of vesicular stomatitis virus replication by toyocamycin

Synthesis of new 2'-beta-C-methyl related triciribine analogues as anti-HCV agents

Ten new beta-D-ribofuranosyl and 2'-beta-C-methyl-beta-D-ribofuranosyl triciribine derivatives 4-13 with various N4 and 6-N substituents on the tricyclic ring were synthesized from the corresponding toyocamycin and new 2'-beta-C-methyl toyocamycin derivatives. The inhibitory studies of these compounds in the HCV replicon assay reveal that some of them possess interesting anti-HCV properties with low cytotoxicity.

Pyrrolo[2,3-d]pyrimidine nucleosides: synthesis and antitumor activity of 7-substituted 7-deaza-2'-deoxyadenosines

A one step synthesis, using the nucleoside 7-iodo-2'-deoxytubercidin (2b) in a Pd(0)/Cu(I)-catalyzed cross coupling reaction furnished a series of 7-alkynyl-2'-deoxytubercidin derivatives. The 7-iodo-, 7-chloro- or 7-bromo 2'-deoxytubercidins 2b-d as well as certain 7-alkynyl derivatives show significant activity against several tumor cell lines, with 7-iodo-2'-deoxytubercidin (2b) as the most effective compound.

Effect of toyocamycin on oncornaviral production by acutely infected cells

The adenosine analogue toyocamycin incorporates into the RNA species of mammalia cells and abolishes at low concentrations of the processing of 45S preribosomal nucleolar RNA into the mature 28 and 18S cytoplasmic ribosomal RNAs. We have previously shown that toyocamycin depresses the production of the Friend leukemia viral complex by chronically infected cells. In this article, we report the study of the action of the drug on viral RNA in acutely infected cells. We found that, although abolishing viral production, the incorporation of toyocamycin does not inhibit the formation of mature viral messenger RNAs nor prevent the synthesis of specific viral proteins. These results are obtained at concentrations of analogue sufficient to abolish the appearance of mature cytoplasmic ribosomal RNA.

[Effect of toyocamycin on the biosynthesis of viral glycoproteins in a cell line chronically infected with a murine retrovirus]

Toyocamycin (TMC), an adenosine analog has been previously reported to inhibit both number and infectivity of retrovirus particles released by chronically infected cells (Bonar et al., 1970; Riman, 1971; Mauchauffé et al., 1979). We have previously shown that loss of infectivity could result from the incorporation of TMC in place of adenosine in the genomic 35S RNA (Larsen et al., 1979). This phenomenon is likely to impair the structure of the viral genome in such a way that reverse transcriptase cannot properly copy the template. Another consequence of the Toyocamycin action on the retrovirus particles released by analog-treated cells was their reduced content in envelope glycoprotein or gp70 (Mathieu - Mahul et al., 1979). In order to find the origin of this defect, which could also explain the loss of infectivity, viral polypeptides present in the cytoplasm of Toyocamycin-treated cells were analyzed by immunoprecipitation with specific antisera. The results indicated a diminution of the biosynthesis of the envelope glycoprotein and other GAG gene-related polypeptides. However, the gpr85env precursor was normally synthesized and processed into its final products (gp70 + p15E), which accumulated in the cells. These result make it likely that Toyocamycin has no specific effect on the virus replicative process in chronically infected cells but acts by deteriorating cellular functions, which are necessary to virus assembly. Indeed, it was found that a membrane fraction corresponding to smooth endoplasmic reticulum and Golgi apparatus was severely reduced if not totally suppressed in TMC-treated cells.