Roundup product are the focus of the article.

Response to: Endocrine disruption and cytotoxicity of glyphosate and roundup in human JAr cells in vitro – Integrative Pharmacology, Toxicology and Genotoxicology

In this article, the authors use the model system of placental tumor cells. This is because they produce hormones, a necessary feature if you’re going to measure how your chemical impacts hormone levels. No one is claiming that a placental tumor is an effective substitute for your average Australian human (who is the one drinking the “roundup water” and hence our target population). Rather, we realize that starting out small and asking targeted questions in a population that we can easily manipulate is the most cost and ethically effective way to begin. However, it’s important to remember that cells are not humans, and many of the things that will hurt single cells don’t bother whole humans (for example, a single cell cannot cope with being immersed in water, whereas humans are encouraged to take baths regularly). The reason for this that there are many more components that make up a human than a cell. Therefore, anything we find in the context of a cell, we need to keep studying closer and closer to the context of our target population. We may find that, when we add back in an immune system, a digestive tract, or even when we switch from mouse to human or male to female subjects, that our results change significantly.

The authors test these placental tumor cells by treating them with both the active compound in roundup, Glyphosate, alone, and also with Glyphosate mixed with other inactive compounds found in the roundup formula. Previously, only Glyphosate had been studied and was thought to pose no threat to humans. The authors in this study find that when you treat cells with the more relevant roundup mixture, hormone levels fluctuated and cell death was higher than when just Glyphosate was used. This is a very important finding and one that highlights the need to do better science testing these compounds with more controls and less assumptions about what is an inactive ingredient. Follow up studies exploring the interplay between compounds will be critical to understanding the environmental risk factors of releasing these synthetic compounds into the drinking water.

However, this is also a very short paper. Most of the time brevity is a good thing, but with science, more measurements means we are more sure of what we are actually seeing. Science is, effectively, blind, and with only one or two measurements it’s easy to mistake your findings for something else entirely. In this paper, the authors simply measure the number of cells left after treatment (MTT assays work by staining the live cells left in the culture dish at the end of the study. The stain can be dissolved and measured quantitatively. It’s a fast an effective way of saving your students from counting thousands of cells by hand, but serves about the same purpose). There are also simple tests you can do that measure how much energy these cells have, or if they’re actively reproducing. One test alone can give you results that are promising but don’t show the whole picture. So, before we take these results as proof that we shouldn’t be drinking the water, we need to see more experiments that expand our understanding of what exactly is the roundup compound doing to the cells, and also expand our test to see if other cell types than placental tumors react the same way.

All of this is to say, that this paper brings up a very good point that contextualizing compounds as they would be found as herbicides can have a profound impact on what that compound does to a cell. This lets us know as scientists that even in our earliest models of studying mixtures like roundup that oversimplifying can lead to misinformation, and potential risks later on. However, saying that this happens to cells at drinking water concentrations of Round Up is slightly misleading, mostly because as discussed earlier, a cell in a culture dish is much more vulnerable than a human body. As a cancer researcher, we see this phenomenon all the time with promising new cancer drugs killing lots of cancer cells in cell culture, but when it actually comes to getting these drugs into tumors, evading the human body’s ability to dilute and diffuse our cancer-killing compounds is no easy feat. In the end, we have to use drug targeting and generally much higher doses than we initially gave to the tumor cells alone to keep up the same cell-killing effects. This is frustrating for cancer patients since low doses of cancer drugs are rarely effective when taken orally, but good news for Australian water drinkers, because it means that your body is pretty good at dealing with potentially damaging compounds that enter your body.

So, before you give up on your Australian vacation plans or let pests eat all your vegetables for fear of using pesticides, remember that what this paper is essentially telling us is that two compounds together may have different effects on a cell than one alone. This finding, especially in the context of chemical pesticides, will be important to track as it moves its way up the relevance ladder into other cell types, and then into organisms that would consume the compound in drinking water as the target human population does. But until we prove that the findings hold up across cells, mice, and ultimately humans, unless you’re a placental tumor, you’re probably safe drinking (or bathing) in the water.

Media coverage: Dr Young: Roundup Herbicide Is Endocrine Disruptor in Human Cells at Drinking Water Levels

Acknowledgments: Many thanks to Dr. Megan M. Emori, a recent graduate from the Human Biology and Translational Medicine program at Harvard Medical School. Also, thanks to Pam Jacques for bringing this article to our attention.

Managing Correspondent: Adam brown

Related SITN Articles: S2N Special Edition on GMOs

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