Structure-activity relationships and mode of action of 5-mercapto-substituted oligo- and polynucleotides as antitemplates inhibiting replication of human immunodeficiency virus type 1

Introduction of a reactive 5-mercapto group into some of the cytosine and/or uracil bases of various oligo- and polynucleotides by partial thiolation resulted in several potent inhibitors of the replication of human immunodeficiency virus type 1 (HIV-1) in primary human lymphocytes. These compounds exhibited little if any toxicity against uninfected peripheral blood mononuclear cells and showed 15 to 75 times higher antitemplate activity against a p66/p51 HIV-1 recombinant reverse transcriptase (RT) than against the DNA polymerase alpha from human lymphocytes. In contrast, the unthiolated oligo- and polynucleotides are void of antitemplate activity, and their apparent inhibitory effect on HIV-1 closely paralleled their toxicity for the cells. Partially thiolated poly(dC) (MPdC) was the most potent of all the compounds tested against HIV-1 in peripheral blood mononuclear cells (50% effective concentration, 1.8 micrograms/ml or 0.019 microM), while showing low cytotoxicity (greater than 100 micrograms/ml). The corresponding unmodified poly(dC) showed no anti-HIV-1 activity at 50 micrograms/ml but had pronounced cytotoxicity. MPdC was also a potent inhibitor of HIV-1 RT (50% inhibitory concentration, 0.30 micrograms/ml). The inhibitory activities of thiolated homooligo(dCs) against both HIV-1 replication and HIV-1 RT increased with increasing chain length. The heterooligonucleotides included in this study were designed as structural analogs of portions of the natural primer of HIV-1 RT, i.e., tRNA(3Lys). An 18-mer analog of the 3' terminus, complementary (antisense) to the primer-binding site of the HIV-1 genome, was attached to an oligo(dC) tail and 5-thiolated; this increased its activity and decreased its toxicity. This compound will serve as a new lead in the development of more effective antitemplates against HIV-1.

Synthesis and antileukemic activity of bis[[(carbamoyl)oxy]methyl]- substituted pyrrolo[2,1-a]isoquinolines, pyrrolo[1,2-a]quinolines, pyrrolo[2,1-a]isobenzazepines, and pyrrolo[1,2-a]benzazepines

A series of bis[[(carbamoyl)oxy]methyl]-substituted pyrrole-fused tricyclic heterocycles were synthesized by using 1,3-dipolar cycloaddition reactions with a trifluoromethanesulfonate salt of an appropriate Resissert compound or with a mesoionic oxazolone intermediate. All of the bis(carbamates) were active in vivo against P388 lymphocytic leukemia with 5,6-dihydro-8-methoxy-1,2- bis(hydroxymethyl)pyrrolo[2,1-a]isoquinoline bis[N-(2-propyl)carbamate] (3c) showing the highest level of activity.

Comparison of the chemical reactivities and antineoplastic activities of alpha,beta-, alpha,beta'-, beta,beta'-, and alpha,alpha'-bis[[[(2-propylamino)carbonyl]oxy]methyl]-substituted pyrroles

The bis[N-(2-propyl)carbamate] derivatives of 2,3-bis(hydroxymethyl)-4,5-diphenyl-1-methylpyrrole (4a), 3,4-bis-(hydroxymethyl)-2,5-diphenyl-1-methylpyrrole (4b), 2,4-bis(hydroxymethyl)-3,5-diphenyl-1-methylpyrrole (4c), and 2,5-bis(hydroxymethyl)-3,4-diphenyl-1-methylpyrrole (4d) were synthesized and the reactivities of the four compounds were compared using the model nucleophile 4-(p-nitrobenzyl)pyridine (NBP). No significant correlation was seen between NBP reactivity and either toxicity or antineoplastic activity in this series. Three compounds 4a, 4b, and 4c gave significant reproducible activity against P388 lymphocytic leukemia; the alpha,alpha'-bis(carbamate) 4d was inactive. The alpha,beta- and alpha,beta'-bis(carbamates) 4a and 4c were evaluated against a panel of mouse tumor homografts and human tumor xenografts implanted under the kidney capsule of mice.