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Analysis of the ex vivo and in vivo antiretroviral activity of gemcitabine.

Clouser CL, Holtz CM, Mullett M, Crankshaw DL, Briggs JE, Chauhan J, VanHoutan IM, Patterson SE, Mansky LM - PLoS ONE (2011)

Bottom Line: However, the use of HU as an antiretroviral is limited by its associated toxicities such as myelosuppression and hepatotoxicity.Higher doses of gemcitabine (3 mg/kg/day and higher) were associated with toxicity as determined by a loss in body mass.These observations together with a recent ex vivo study with HIV-1, suggest that gemcitabine has broad antiretroviral activity and could be particularly useful in vivo when used in combination drug therapy.

View Article: PubMed Central - PubMed

Affiliation: Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America.

ABSTRACT
Replication of retroviral and host genomes requires ribonucleotide reductase to convert rNTPs to dNTPs, which are then used as substrates for DNA synthesis. Inhibition of ribonucleotide reductase by hydroxyurea (HU) has been previously used to treat cancers as well as HIV. However, the use of HU as an antiretroviral is limited by its associated toxicities such as myelosuppression and hepatotoxicity. In this study, we examined the ribonucleotide reductase inhibitor, gemcitabine, both in cell culture and in C57Bl/6 mice infected with LP-BM5 murine leukemia virus (LP-BM5 MuLV, a murine AIDS model). Gemcitabine decreased infectivity of MuLV in cell culture with an EC50 in the low nanomolar range with no detectable cytotoxicity. Similarly, gemcitabine significantly decreased disease progression in mice infected with LP-BM5. Specifically, gemcitabine treatment decreased spleen size, plasma IgM, and provirus levels compared to LP-BM5 MuLV infected, untreated mice. Gemcitabine efficacy was observed at doses as low as 1 mg/kg/day in the absence of toxicity. Higher doses of gemcitabine (3 mg/kg/day and higher) were associated with toxicity as determined by a loss in body mass. In summary, our findings demonstrate that gemcitabine has antiretroviral activity ex vivo and in vivo in the LP-BM5 MuLV model. These observations together with a recent ex vivo study with HIV-1, suggest that gemcitabine has broad antiretroviral activity and could be particularly useful in vivo when used in combination drug therapy.

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Gemcitabine inhibits MuLV replication in cell culture in the absence of toxicity.1A. Infectivity of MuLV. MuLV containing GFP were produced from 293T cells and used to infect U373-MAGI-CXCR4CEM cells that were treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments. 1B. Toxicity of gemcitabine in U373-MAGI-CXCR4CEM cells treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments.
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pone-0015840-g001: Gemcitabine inhibits MuLV replication in cell culture in the absence of toxicity.1A. Infectivity of MuLV. MuLV containing GFP were produced from 293T cells and used to infect U373-MAGI-CXCR4CEM cells that were treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments. 1B. Toxicity of gemcitabine in U373-MAGI-CXCR4CEM cells treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments.

Mentions: Before examining the antiviral activity of gemcitabine in vivo, we first examined the ability of gemcitabine to inhibit MuLV in cell culture. To do this, a GFP-tagged MuLV was pseudotyped with VSV-G and used to infect target cells that had been pretreated with increasing concentrations of gemcitabine. Flow cytometry was then used to determine the percentage of infected cells. As shown in Fig. 1A, gemcitabine potently decreased MuLV infectivity in a concentration-dependent manner with an EC50 in the low nM range. Additionally, there was no toxicity seen at the concentrations of gemcitabine needed to inhibit viral replication when the cells were exposed to gemcitabine for the same time as was used to assess gemcitabine's effect on infectivity (Fig. 1B).


Analysis of the ex vivo and in vivo antiretroviral activity of gemcitabine.

Clouser CL, Holtz CM, Mullett M, Crankshaw DL, Briggs JE, Chauhan J, VanHoutan IM, Patterson SE, Mansky LM - PLoS ONE (2011)

Gemcitabine inhibits MuLV replication in cell culture in the absence of toxicity.1A. Infectivity of MuLV. MuLV containing GFP were produced from 293T cells and used to infect U373-MAGI-CXCR4CEM cells that were treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments. 1B. Toxicity of gemcitabine in U373-MAGI-CXCR4CEM cells treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3021508&req=5

pone-0015840-g001: Gemcitabine inhibits MuLV replication in cell culture in the absence of toxicity.1A. Infectivity of MuLV. MuLV containing GFP were produced from 293T cells and used to infect U373-MAGI-CXCR4CEM cells that were treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments. 1B. Toxicity of gemcitabine in U373-MAGI-CXCR4CEM cells treated with the indicated concentrations of gemcitabine. The data represents the average ± SD of three independent experiments.
Mentions: Before examining the antiviral activity of gemcitabine in vivo, we first examined the ability of gemcitabine to inhibit MuLV in cell culture. To do this, a GFP-tagged MuLV was pseudotyped with VSV-G and used to infect target cells that had been pretreated with increasing concentrations of gemcitabine. Flow cytometry was then used to determine the percentage of infected cells. As shown in Fig. 1A, gemcitabine potently decreased MuLV infectivity in a concentration-dependent manner with an EC50 in the low nM range. Additionally, there was no toxicity seen at the concentrations of gemcitabine needed to inhibit viral replication when the cells were exposed to gemcitabine for the same time as was used to assess gemcitabine's effect on infectivity (Fig. 1B).

Bottom Line: However, the use of HU as an antiretroviral is limited by its associated toxicities such as myelosuppression and hepatotoxicity.Higher doses of gemcitabine (3 mg/kg/day and higher) were associated with toxicity as determined by a loss in body mass.These observations together with a recent ex vivo study with HIV-1, suggest that gemcitabine has broad antiretroviral activity and could be particularly useful in vivo when used in combination drug therapy.

View Article: PubMed Central - PubMed

Affiliation: Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, United States of America.

ABSTRACT
Replication of retroviral and host genomes requires ribonucleotide reductase to convert rNTPs to dNTPs, which are then used as substrates for DNA synthesis. Inhibition of ribonucleotide reductase by hydroxyurea (HU) has been previously used to treat cancers as well as HIV. However, the use of HU as an antiretroviral is limited by its associated toxicities such as myelosuppression and hepatotoxicity. In this study, we examined the ribonucleotide reductase inhibitor, gemcitabine, both in cell culture and in C57Bl/6 mice infected with LP-BM5 murine leukemia virus (LP-BM5 MuLV, a murine AIDS model). Gemcitabine decreased infectivity of MuLV in cell culture with an EC50 in the low nanomolar range with no detectable cytotoxicity. Similarly, gemcitabine significantly decreased disease progression in mice infected with LP-BM5. Specifically, gemcitabine treatment decreased spleen size, plasma IgM, and provirus levels compared to LP-BM5 MuLV infected, untreated mice. Gemcitabine efficacy was observed at doses as low as 1 mg/kg/day in the absence of toxicity. Higher doses of gemcitabine (3 mg/kg/day and higher) were associated with toxicity as determined by a loss in body mass. In summary, our findings demonstrate that gemcitabine has antiretroviral activity ex vivo and in vivo in the LP-BM5 MuLV model. These observations together with a recent ex vivo study with HIV-1, suggest that gemcitabine has broad antiretroviral activity and could be particularly useful in vivo when used in combination drug therapy.

Show MeSH
Related in: MedlinePlus