INDUCTION OF HIV-1 FROM LATENTLY INFECTED CELL LINES BY CHEMICAL CARCINOGENS

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The U1 cell line, derived from a chronically infected U937 culture harbors a latent HIV genome which can be induced in the presence of TPA, TNFa, IL-6 and a few other lymphokines. The effect of various chemical carcinogens and environmental mutagens were examined for their ability to induce virus from this cell line with the objective of identifying risk factors of physiologic relevance that may affect disease progression in AIDS. U1 cells were treated with 2 different concentrations of the various carcinogens and at different times after infection, cell-free supernatant was collected for measurement of p24 and RT levels, and cell pellets for DNA and RNA preparation. Cells were treated with TPA as a positive control for viral induction. Virus production, as measured by p24 antigen assays, was observed in the supernatants of cells treated with TPA at the earliest time point, 3 days. Interestingly, 2 of the agents examined, benzopyrene (BP) and alpha hexachlorohexane (aHCH) induced virus production comparable to that of TPA, although at a later time point (6-12 days of treatment). Enhanced levels of RNA were observed in BP and aHCH treated cultures. A ten fold increase in virus production was observed using transmission electron microscopy. Other environmental mutagens that were analyzed included dimethyl nitrosamines (DMNA), various isomers of nicotine (NNN, NNK) and aflatoxin B. p24 antigen levels increased 5 fold with DMNA, 10- fold with aflatoxin B and 100 fold with NNK at five days post treatment. Among the various drugs of abuse analyzed, cocaine, heroine, LSD and PCP showed 7-20 fold induction of viral antigen. Viral antigen levels showed a 10 fold increase in cells treated with Aflatoxin B. Hormonal induction of virus is also being assessed in this cell system. We are currently investigating the mechanism of virus induction, the pattern of RNA and protein synthesis in the induced U1 cells, as well as the role of cellular and viral factors that may control activation of the viral genome.