Tuesday, March 13, 2012

DNA Binding Drugs


Drugs are consumed daily by individuals all over the world in order to treat a variety of different illnesses. Research to develop new drugs and to identity potential drug targets within the human body are essential in preventing, treating, and maintaining these illnesses. One important drug target is DNA. DNA contains the genetic instructions used in the development and functioning of all living organisms.

DNA has two main functions; transcription and replication. Transcription is the process from DNA to RNA, and then RNA is translated into proteins. Proteins are involved in all body processes and are essential in maintaining life. Replication is important for cell growth as well as a cell's ability to successfully divide. Both transcription and replication are vital to cell survival and smooth functioning of all body processes. Most DNA drugs target these two functions.

There are a few ways drugs are able to bind to DNA. One way is by controlling enzymes and factors involved in transcription. Another possibility is for drugs to bind to parts of DNA and interfere with the interactions between DNA and proteins. Take for example telomerase inhibitors, which are used in cancer treatment. Telomeres are located at the end of chromosomes and are important in preventing damage in DNA replication. In normal (somatic) cells, the cells have an end date or eventually die. In tumor cells, however, the telomere ends are kept more stable, thus allowing tumor cells to survive and continue to grow. Telomerase inhibitors work by stopping the action of an enzyme known as reverse transcriptase telomerase. This particular enzyme is what allows the tumor cells to survive and maintain growth; therefore these drugs can cause the tumor cells to die via apoptosis, programmed cell death.

Current research is focused on how drugs can actually bind to DNA and affect gene regulation. Gene regulation is a process in which a cell determines which genes it will express and when it will express them. All cells in the human body contain a copy of an individual’s DNA, which contains thousands of genes. These genes can either be turned on or off by the cells. For example, a bone cell could turn on genes to make it a bone cell, whereas in a skin cell the gene for bone cells would be turned off. Drugs that can bind directly to DNA and affect gene regulation could have an enormous impact on genetic diseases, HIV, and cancer.

This research is supported by a current article from ScienceDaily, Tangled Up in DNA: New Molecule Has Potential to Help Treat Genetic Diseases and HIV. Chemists at The University of Texas at Austin developed a drug called NDI that works by tangling itself inside DNA. The goal of these researchers is to use the NDI drugs mechanism for binding to DNA to target specific areas of DNA that diseases are found in order to turn gene expression on or off. In the article one of the researchers discussed using NDI to locate the HIV region of DNA and be able to " just sit on it and keep it quiet".

DNA is a key target for drug delivery. Hopefully future research will lead to the development of a drug that can target DNA and aid in the treatment of life threatening diseases. If you are interested in this topic please listen to the audio segment on DNA binding drugs by Nicole, Jake, and Charlie, where we will explore this topic further. 

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