Adhya is the second winner of our science writing competition, and entered the 13-15 year old category. Adhya is 15 years old and from the USA, our first winner outside of the UK! Adhya’s piece is all about how some cancer treatments prevent cell growth. It was an insightful read, and incredibly impressive for someone so young. Congratulations Adhya.
Curing Cancer by Cancelling Cell Growth
Hey everybody! Today we’re going to talk about something called a thymidylate synthase inhibitor, a substance that works against the effects of cancer and growth of tumours in the body.
Before we get started— whatever you’re thinking right now, there’s no need to be intimidated by the large words. I’m going to give you all the context you need to understand our topic, even if you’ve never studied biology before, and I’ll take you step-by-step through the details of how and why this treatment works. So, without further ado; Let’s dive in.
Our DNA, for those of you who don’t yet know, is what carries the instruction for all of our body’s functions— telling our cells to make proteins that allow for the completion of tasks, and carrying out the jobs of our internal organs. One of the cellular tasks that gets executed most frequently is cell division and replication, which as we all know, is a good thing— because it’s what lets our body grow and maintain a supply of healthy cells as older ones die off. But there are times, however, when cell division isn’t such a good thing and cancer, as it occurs in humans and other species all over the world, is a prime example of this.
Tumours, the defining characteristic of a cancerous condition, occur in people when a portion of their cells don’t go through the process of mitosis, or cell division, properly; dividing too much/too fast in a way that they shouldn’t, and building up harmfully in a group. Stopping tumour growth is one of the primary challenges of treating and/or potentially curing cancer, and so many treatments that scientists work on and oncologists (cancer doctors) administer to their patients are substances called antimetabolites, which interfere with the synthesis phase of the cycle of cell growth and division. This is because if tumour cells can’t divide, then the tumour can’t grow, and the cancer can’t get worse. And without any new cells, the tumour — and thereby the cancer — will eventually die out.
So how exactly do thymidylate synthase inhibitors, which are a type of antimetabolite, stop cells from dividing? The key lies in mitosis, and specifically: the very same DNA that enables mitosis to occur.
Every sequence of DNA is made up of a pattern of four distinct nitrogenous bases, (called adenine, guanine, cytosine and thymine), that can form discrete pairs and create sections that encode certain genetic information. When cells divide and allow a mass of the body to grow, including tumor mass, they replicate the DNA inside them to give it to the cell copy that’s being produced, which means that all of these bases have to be replicated as well. This, my friends, is where the strategy of cancer researchers comes into picture.
In the synthesis of thymine, one of DNA’s four bases, there is an enzyme called thymidylate synthase, which makes changes to a handful of other substances (the names of which are long, but the properties of which are fascinating if you decide to do more research) and plays a key role in allowing this base to be replicated. However, a thymine synthase inhibitor binds to this enzyme, and prevents it from being able to interact with the other components of the synthesis process, and thus prevents new thymine from being successfully assembled. What this means is that the DNA itself cannot form, since it won’t have all of the parts it needs to construct itself, and without DNA, a cell can’t successfully divide or live past division; meaning that any new cells the treated area tries to spawn will die, and become unable to add to or maintain its mass.
Simply put, this treatment is one of many that seek to dampen tumour growth by targeting cell growth, and one of many that might one day lead to a potential cure for certain types of cancer as a whole. The method isn’t perfect, but today, it’s already in use. So will you and I ever see the day that cancer gets cured for good? Maybe we will, and maybe factors stopping cell growth will play a vital role in that.