Toxicologists Study How Pharmaceuticals Affect Genes  

Tuesday, March 20, 2012 thescienceteam View Comments

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Autism Speaks Director of Research for Environmental Science Alycia Halladay, Ph.D., reports back from the Society of Toxicology’s annual meeting.

Epigenetics seems to be the word of the year in science and medicine. It definitely played prominently in the presentations at the Society of Toxicology’s annual meeting I attended last week in San Francisco. Toxicologists study the adverse effects of substances in the environment. This year they were particularly excited about new findings on the epigenetic effects of pharmaceuticals. Some medications, it appears, have side effects that include altering how our genes function.

For decades, researchers have studied how certain chemicals cause genetic mutations that can lead to diseases like cancer. Epigenetics involves more subtle interactions between environmental exposures and our genes. Certain chemicals appear to “dial up” or “dial down” gene activity without actually changing, or mutating, the gene itself.

The goal is to understand what problems these epigenetic changes can produce down the road, either in the person exposed to chemicals or in his or her children.

At this year’s meeting, there was much discussion about how the epigenetic effects of medications may contribute to conditions like breast cancer, leukemia and early onset of puberty. We’ve only begun studying the role of epigenetics in developmental disorders. So I am particularly interested in what the autism research community can learn from epigenetics research in other fields of medical research. 

In this regard, I see similarities between autism and breast cancer. Like autism, breast cancer presents in complex ways. It varies in age of onset and tumor type. Like autism, breast cancer risk is influenced by a number of different genes and environmental exposures such as hormone levels, breast feeding and alcohol consumption. Breast cancer researchers are even looking at subtypes of breast cancer and determining what exposures and risk factors affect which subtypes. For example, researchers have long thought that breast feeding protects against all types of breast cancer. Now evidence suggests that it protects against only some types. Researchers are also looking at critical windows – such as prenatal development – when exposure to chemicals or hormones may lead to cancers or developmental problems later in life. There may be other life stages where exposure is relatively innocuous.

These are areas we need to further explore in autism research. We need to better understand subtypes of autism, which exposures affect which subtypes and during what windows of susceptibility. Autism Speaks is currently funding related studies. Geier Grant awardee Dani Fallin is looking at how infections, nutrition and chemical exposures during prenatal development and infancy can produce epigenetic changes and affect autism risk.

In particular, it’s important to pinpoint the crucial windows when exposures may have a particularly strong effect. We know, for example, that the second trimester of pregnancy is a time of rapid early brain development. Increasingly, evidence suggests that this is one of the critical windows of exposure for autism.

I came away from last week’s conference hopeful that, as a group, toxicologists are fully engaged and excited about surmounting the research challenges ahead. More than an academic exercise, they were already discussing the importance of including epigenetic assays in the safety testing of future medicines. No doubt, we’ll have more exciting news to report in the coming year.

Meanwhile you can explore related Autism Speaks funded studies by following these links to our grants in the areas of epigenetics and environmental factors. None of this research would be possible without the support of our donors and volunteers. Thank you! 

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