A Taxing Issue: How Human T-lymphotropic Virus Can Cause Leukemia In Adults

Researchers have identified a potential new mechanism through which human T-lymphotropic virus type-1 (HTLV-1) causes leukemia in adults. The findings, published this week in the online open access journal Retrovirology, represent the first time that a reduction in histone protein levels has been linked to viral infection and the development of cancer.

HTLV-1 is a retrovirus that causes adult T-cell leukaemia/lymphoma (ATLL). A single protein made by the virus, Tax, is thought to be enough to trigger cancer development. Tax has a number of effects in the cell, including promoting inappropriate cell division, repressing DNA repair mechanisms and causing genomic instability. These effects are thought to combine and cause cancer, although the exact details of the process are unclear.

James Bogenberger and Paul Laybourn from Colorado State University, USA found that the levels of histone proteins and histone transcripts were lower in T-cell lines infected with HTLV-1 than in uninfected cell lines. They also showed that Tax could cause a drop in the levels of histone transcript in uninfected cells.

Histone proteins are required for the packaging of DNA in cell nuclei and are involved in many key processes associated with DNA, including transcription, repair and replication. The authors suggest that Tax uncouples cell division and replication-dependent histone gene expression, allowing cell division to continue while the levels of histone protein fall.

They write: “We suggest Tax repression of replication-dependent histone gene expression will result in reactivation of viral gene expression, deregulation of cellular gene expression and genomic instability. All of these effects may contribute to the development of adult T-cell leukemia/lymphoma. To our knowledge, this is the first example of a reduction of histone levels correlating with viral infection and cancer development.”

Source: BioMed Central

Related stories:

Pond scum could be key to new cancer therapies
Researchers at the University of Illinois at Chicago College of Pharmacy are collaborating with the Ohio State University and two other organizations to discover new cancer therapies derived from natural sources such as pond scum and plants from tropical rainforests.
Scientists discover key patterns in the packaging of genes
Although every cell of our bodies contains the same genetic instructions, specific genes typically act only in specific cells at particular times. Other genes are "silenced" in a variety of ways. One mode of gene silencing depends upon the way DNA, the genetic material, is packed in the nucleus of cells.
Combination of 2 novel anti-cancer agents may help fight CML resistant to current therapy
Virginia Commonwealth University Massey Cancer Center researchers have identified that a combination of novel anti-cancer compounds is able to kill chronic myelogenous leukemia cells previously resistant to conventional forms of therapy.
The good and bad side of anti-cancer compounds
Compounds known as “HDAC inhibitors” exhibit cancer-killing activities in cultured cells. While they are currently being tested as anti-cancer agents in clinical trials, just how they execute their effects is unclear.
A protein that triggers aggressive breast cancer
SATB1 is a nuclear protein well known for its crucial role in regulating gene expression during the differentiation and activation of T cells, making it a key player in the immune system. But SATB1 has now revealed a darker side: it is an essential contributing factor in the most aggressive forms of breast cancer.
Research suggests targeted treatment strategies for lupus
New research provides clues about the causes of lupus symptoms and suggests specific new targeted treatment strategies, according to Nilamadham Mishra, M.D., from Wake Forest University Baptist Medical Center, in presentations this week at the American College of Rheumatology in Boston.
Enzyme regulates brain pathology induced by cocaine, stress
Researchers have uncovered a key genetic switch that chronic cocaine or stress influences to cause the brain to descend into a pathological state. In studies with mice they showed how chronic cocaine changes gene activity to enhance the addictive reward from the drug. And they showed similarly how chronic stress induces the same kinds of changes that hypersensitizes the brain, causing depression-like symptoms.
Novel strategy under study for aggressive leukemia
A novel strategy to hopefully beat into oblivion one of the most aggressive forms of acute myelogenous leukemia combines the strengths of some of the newest leukemia agents, researchers say.

News discussion:

Medicine & Health news