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Cancer medication can lure HI viruses out of hiding
Researchers from the University of North Carolina have investigated why the HIV virus in an infected person's body can be kept at bay but cannot be defeated. A possible clue is special cells that contain the genetic material of the AIDS pathogen, but do not themselves produce viruses. Scientists have come closer to the cause in several studies. Based on the research results, the researchers are now of the opinion that latent HIV infection can be treated with medication. To do this, a cancer drug had to be administered in order to "lure latent HI viruses out of sleep".
Previous research had determined that a drug that was actually designed for cancer therapy can animate so-called sleeper cells in the presence of an HI virus infection. According to the results available, the active ingredient "Vorinostat" has the property that cells that contain the pathogen genome but do not release viruses can still become active. The viruses are put together and released from the cell, as the research team reported in their study report in the journal "Nature". As a result of this determined effect, “HIV medicines would once again have a target to tackle the HIV infection”, as the scientists around David Margolis and colleagues sum up.
Latent HIV infection could be treatable "The results are the first evidence that latent HIV infection can be treatable", they emphasize in the technical report. If there was a latent infection, the body's own defense cells would contain genetic information from the virus, "but would not produce any new viruses with this blueprint". The problem: conventional drugs in HIV therapy have no point of attack under these circumstances. The infection would "successfully hide from a drug attack of antiretroviral therapy".
For the examination, 16 subjects' blood was drawn and then examined in the laboratory. Cells of the "CD4-positive helper cells" type were isolated from the participants' blood and mixed with the active ingredient vorinostat in a test tube. Six hours later, the so-called gene expression in the cells of 11 participants was "significantly up-regulated". The active ingredient struck in eight of the eleven sera. Subjects in whom the cancer drug showed an effect in the test tube were then given the active ingredient orally. "The gene expression of the HIV genetic material has increased by one and a half to ten times in all of them," explained Margolis and colleagues.
Certain proteins attract HI viruses The study has shown that certain enzymes can attract the viruses from the sleeping cells. According to the researchers, this assumption has been around for some time, because the histone deacetylase inhibitors could expose genome regions. This would activate the gene sequences, with the result that the blueprints can be read out.
The researchers from the University of North Carolina at Chapel Hill, in cooperation with other research institutions such as the pharmaceutical company Merck and other universities, have now been able to confirm the suspected mechanism. "The molecular mechanism works and with the histone deacetylase inhibitor vorinostat," the authors write. The named drug ingredient is already approved for the treatment of cancer patients on the US drug market and is marketed by the pharmaceutical company with the name "Zoliza".
The first preliminary results of the study results were already presented at the conference "Conference on Retroviruses and Opportunistic Infections" in early March 2012 in Seattle. More details will be announced this week at the World AIDS Conference in Washington D.C. reported.
Valuable study but unanswered questions about dosage The results are causing a stir among experts in Germany as well. "The study is very valuable," commented Prof. Dr. Georg Behrens from Clinic for Immunology and Rheumatology at the Medical University in Hanover (MHH). Behrens is researching HIV therapies with colleagues. “We worked with very sensitive and also new methods. It is surprising that the effect of the drug was even more pronounced in humans than in cell culture. "However, according to the expert, some important aspects were not explained in the" Nature "report, for example, it remained unclear whether a single dose of the cancer drug was sufficient to wake up all latently dormant HIV cells, and not every cell dies when it produces HI viruses and releases them into the blood. (sb)
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