Cisplatin stimulates the expression from the human immunodeficiency virus long terminal repeat sequences in human fibroblasts

Sequence-specific recognition of the HIV-1 long terminal repeat by distamycin: a DNAase I footprinting study

Pharmacological modulation of the interaction between transcription factors and target DNA sequences of cellular and viral genes could have important effects in the experimental therapy of a large variety of human pathologies. For instance, alteration of the DNA/protein interaction might be among the molecular mechanisms of action of DNA-binding drugs, leading to an inhibition of the expression of genes involved in the control of in vitro and in vivo growth of neoplastic cells and virus DNA replication. Natural oligopeptides, such as distamycin, are powerful inhibitors of the interaction between nuclear factors and target DNA sequences and, therefore, have been proposed as compounds retaining antibiotic, antineoplastic and antiviral properties. In this study we performed DNAase I footprinting analysis using a PCR product mimicking a region of the long terminal repeat (LTR) of the human immunodeficiency type 1 (HIV-1) retrovirus. The data obtained suggest that distamycin binds to different regions of the HIV-1 LTR depending on the DNA sequence. Electrophoretic mobility shift assays using both crude nuclear extracts from the Jurkat T-lymphoid cell line and the recombinant proteins transcription factor IID and Sp1 suggest that distamycin differentially inhibits the interaction of these two proteins with their specific DNA target sequences, in good agreement with the results obtained by DNAase I footprinting analysis.

Mitomycin C stimulates the expression of human immunodeficiency virus long terminal repeat sequences in rat and human fibroblasts

We have employed a recombinant plasmid, pBHIV1, carrying the long terminal repeat (LTR) sequences of the human immunodeficiency virus-1 (HIV-1) linked to the reporter chloramphenicol acetyl transferase (CAT) gene and to the aminoglycoside phosphotransferase (aph) gene as a selectable marker. We have introduced pBHIV1 into rat 208F and human MRCSV40TGR fibroblasts and obtained stable geneticin resistant RFBHIV1-1 and SVTGHIV1-1 cells, respectively. Both transfectant cells express CAT activity from the HIV LTR promoter. The response to the antineoplastic drug mitomycin C was studied on the LTR regulated CAT activity in both cell lines. It was found that mitomycin C at 10 micrograms/mL concentration stimulates the expression of CAT from the HIV LTR 77-fold in rat RFBHIV1-1 and 3.1-fold in human SVTGHIV1-1 cells.

Carboplatin as opposed to cisplatin does not stimulate the expression of the human immunodeficiency virus long terminal repeat sequences

The recombinant plasmid pBHIV1 carrying the long terminal repeat (LTR) of the human immunodeficiency virus 1 (HIV-1), linked to the chloramphenicol acetyl transferase (CAT) gene, was introduced into human and rat fibroblasts. Stable transfectants resistant to geneticin expressed CAT activity from the HIV-1 LTR. It was found that the cytotoxic drug cis-diammine(1,1-cyclobutanedicarboxylato)platinum(II) (carboplatin) at concentrations from 1 x 10(-6) to 1 x 10(-4) M does not stimulate the expression of CAT from the HIV-1 LTR. These results differ from previous studies with the related drug cis-diamminedichloroplatinum(II) which showed stimulation of gene expression from the HIV-1 LTR and suggest that carboplatin could be used in the treatment of cancer patients with Acquired Immune Deficiency Syndrome.

Doxorubicin stimulates transcription from the human immunodeficiency virus long terminal repeat sequences

A recombinant plasmid carrying the long terminal repeat (LTR) of the human immunodeficiency virus 1 (HIV-1) linked to the reporter chloramphenicol acetyl transferase (CAT) gene was stably introduced into rat liver cells. The transfectant cells expressed CAT activity from the HIV LTR. The response to doxorubicin was studied and it was found that at the optimum concentration of 20 micrograms/ml doxorubicin, the expression of CAT from the HIV LTR was stimulated by 65-fold. Our results suggest caution against therapy including doxorubicin in the treatment of AIDS patients.