1 year ago
27 May, 2022
In junior school, I was fascinated by what we were taught under the theme of “nature studies”. That is, what was around us and what we knew about how it worked. This moved me to want to be a scientist once I knew there was such a thing! In secondary school, my passions were the science subjects of physics, mathematics and especially chemistry. I went on to university to read chemistry. But soon changed to biochemistry as I thought this would bring me closer to understanding the workings of life. And help me directly contribute to enhancing a healthy life experience.
Several years ago, I started a major line of research investigating how certain types of chemical pollutants can be toxic and cause disease. One major mechanism of toxicity, which we were interested in exploring, was how classes of chemicals known as “endocrine disrupting chemicals” (EDCs) could interfere with how our body’s hormone function.
This is extremely important as virtually all of our body’s functions. Starting with early growth and development, they are controlled by hormones of different types. Therefore, any interference in hormone function can lead to birth defects or other diseases later in life, such as obesity, diabetes and cancer.
EDCs have an immediate link with breast cancer. This is because many breast cancers require hormones, particularly oestrogen, to grow. So a chemical that can mimic the effects of oestrogen can, in principle, stimulate the growth of many breast cancers. The classical type of EDCs that fall into this category are bisphenols used to make plastics.
Bisphenols are used to manufacture certain clear plastics and resins, which are extensively used in food and drink packaging. They can leach from packaging into food and drink and so can lead to daily ingestion of these EDCs. The first bisphenol to be used was bisphenol A (BPA). BPA is a potent oestrogen mimic. It has caused much concern amongst the public, leading some nations to restrict its use.
In response, the plastics manufacturing industry has been replacing BPA with other bisphenols. In an effort to circumvent regulatory restrictions and allay public concerns by manufacturing “BPA-free” products. However, previous research by my group, funded by Breast Cancer UK, found that many of the most commonly used BPA alternatives are just as oestrogenic as BPA. Or, more so, in stimulating the growth of breast cancer cells. These findings have raised serious concerns about their safety.
In the latest Breast Cancer UK-funded project in my group, we investigated the effects of a bisphenol mixture on human cancerous and non-cancerous breast cells. We decided to study a mixture of different bisphenols since people will be exposed to more than one bisphenol in the real world. The cancerous and non-cancerous breast cells were treated with BPA alone and a mixture of bisphenol A, bisphenol S, bisphenol F, bisphenol AP, bisphenol AF, bisphenol Z and bisphenol B.
In addition, to monitoring general growth, we looked at the total pattern of gene function in the three different breast cell types. To see if the bisphenol mixture gave rise to changes that could suggest progression to breast cancer. Our results showed that all three of the breast cell types we treated resulted in alterations in the pattern of the gene function. However, one of the non-cancerous cell types we investigated, MCF-10A, showed a much greater change in its gene function, with over 2200 genes being perturbed.
The most pronounced changes in gene expression suggested a disturbance in a biochemical system in the cells known as the ubiquitin-proteasome pathway. It has been linked with various cancerous states, including breast cancer. Therefore, our findings showing that bisphenols can impact this pathway suggest that they may either trigger breast cancer or stimulate its growth. Or both.
Our major hurdle was identifying the best types of breast cells to use and the most appropriate and feasible way to grow them. We tried growing one type of non-cancerous cell as 3-dimensional spheres to mimic the natural structure of breast tissue. But this gave very variable and unreliable results. So we resorted to growing three different breast cell types as 2-dimensional layers. It is not ideal, but straightforward and allowed us to undertake our experiments successfully.
Our findings add to the growing body of evidence that it is crucial to test the effects of mixtures of bisphenols when evaluating their health risks and to test in more than one type of breast cell.
On a more personal level, our most recent findings will help guide the next phase of our research investigating links between bisphenols and breast cancer.
The support from Breast Cancer UK has allowed us to undertake research that otherwise would not have been possible. Without the support of Breast Cancer UK, my group would not have been able to start and continue its work on identifying risk factors for breast cancer. Stemming from exposure to chemical pollutants, especially bisphenols.
Breast Cancer UK and my group very much see eye-to-eye on the point that it is far better to identify risk factors for breast cancer and educate people on how to change their lifestyles to prevent breast cancer from arising in the first place. It has been a pleasure to be associated with Breast Cancer UK over the years. I very much hope we can continue to work together for many years to come.
This project has two major objectives.
First, we will undertake a survey of the human population and identify which bisphenols they are exposed to daily. We will do this by analysing a urine sample from 100 volunteers collected over 24 hours and measuring a spectrum of 15-20 different bisphenols, which we believe are most likely to be present. I have to say that I find it somewhat shocking that such a survey has not been conducted in the past. Which means we don’t actually know which bisphenols people are exposed to. It’s great that Breast Cancer UK is finally making such a survey possible!
Second, we will test mixtures of bisphenols identified by the population survey on human breast cells for their potential to initiate and stimulate the growth of breast cancer.
As usual, we hope our results will advise people on how to protect themselves better. And minimise their chances of getting breast cancer.
We also hope that our results will arm Breast Cancer UK to apply political pressure. So that more appropriate regulatory measures are implemented regarding bisphenol exposures to protect public health better.
Science is not immune from dogma. I admire all scientists who, based on their work’s findings, have stood against the prevailing dogma. If that is what the evidence showed, even if they faced ridicule! Therefore, amongst many others, I particularly admire Galileo Galilei, Albert Einstein, Jane Goodall and Rachel Carson. The courage and fortitude that such individuals showed are inspirational.
My greatest pleasure is being with my wife and enjoying the beauty of nature. This nourishes my heart and soul.
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