Oxygen & the Lack of It — What Does It Have to Do with Cancer?

How is a lack of oxygen linked to the spread of cancer?

Hypoxia is a condition in which the body or a particular region has an oxygen deficiency.

(Photo: iStockphoto)

Perhaps the most instinctive, effortless and natural activity living beings do is breathe. We breathe every second that we exist, because that’s the only way we can exist. But what makes our lives dependent on it?

The answer lies in one word — oxygen.

What happens when this simple process of breathing in-and-out gets disrupted? When our bodies don’t get enough oxygen? 

This is precisely what William Kaelin Jr., Sir Peter Ratcliffe and Gregg Semenza — Nobel prize for medicine 2019 winners — aimed to explore. Their research delves into the way the cells in our bodies sense, react and adapt to varying levels of oxygen. Why is their work so important? How does it help us better understand other diseases and conditions like cancer? FIT explains.

How Does the Body Respond to a Lack of Oxygen?

(Photo: iStockphoto)

Dr Prashant Borade, Head of Critical Care, Global Hospital, Mumbai, lays out the physiology for us in simple terms: Oxygen is required for basic cell functions of the body. The mitochondria in our cells uses it and converts food into energy, which is transferred to all organs via blood. When there is insufficient oxygen, cells are unable to function properly and produce chemicals that are not routinely produced. Many of these chemicals are harmful. This is where the body’s defense mechanism kicks in.

“A hormone called erythropoietin is released by the kidneys to stimulate the bone marrow and create more red blood cells. These cells have hemoglobin that carries the oxygen inside the body. This helps carry more oxygen and also demands more oxygen from the lungs.”

Dr Prashant Borade

Another mechanism, he adds, is by increasing the pumping rate of the heart. The heart pumps faster so that blood is circulated faster — and this increases the oxygen supply.

There are various conditions where oxygen might become low — leading to a condition known as hypoxia. Heart failure, lung problems like asthma and bronchitis, stroke, or when you are at a high altitude — this could all cause oxygen deficiency.

While the body does respond with some mechanisms, there is a limit to how much it is able to manage. Tiredness, fatigue, headache and breathlessness are some of the initial symptoms to appear. But as the the deficiency intensifies, each and every organ of the body fails to perform its job.

What happens when your body continues to receive less oxygen than it needs? Dr Supriya Bali, Associate Director of Internal Medicine at Max Multi Specialiy Centre explains.

“Vital organs like heart and brain get affected the fastest. But it’s essential to understand that all organs are connected to each other. So the immediate reaction of the body is to breathe. Heart rate increases, cells start multiplying and more oxygen is produced. But this is short-term. If oxygen is not supplied, the damage could be permanent.”

Dr Supriya Bali

Why is this Exciting For Treating Other Diseases?

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To particularly understand what happens to our brains, FIT spoke to Dr Manjari Tripathi, Neurologist at AIIMS, Delhi. “The air hunger that oxygen deficiency leads to in the brain affects our cognitive abilities and weakens memory. In extreme cases, it can cause severe stroke and permanent damage.”

“How our cells are reacting to less oxygen is a revolutionary mechanism in terms of treating other conditions. For instance, if oxygen is deprived to an abnormal area, such as in and around cancer and tumor cells, it can cause a shrinkage of those cells.”

Dr Manjari Tripathi

Dr Sameer Kaul, Senior Consultant Oncology and Robotics, Apollo Cancer Institute, New Delhi, breaks down the way in which this lack of oxygen and the resultant mechanism can lead to the spread of cancer cells.

He explains, “A lack of oxygen works on the genetic material of the cell. It leads to the multiplication of red blood cells and also the formation of endothelium cells that line the blood vessels, which causes sprouting and increased replication of new small blood vessels. This is one of the mechanisms also behind the spread of cancer. When there are new blood vessels in an area, there could be a sign of cancer in that tissue.”

“So when you understand how these cells proliferate and how they affect the immune system, you can either support these mechanisms or inhibit them. In the case of cancer cells, it needs to be inhibited from spreading. Vascular endothelial growth factor (VEGF) blockers exist for this purpose. These drugs block the formation of genes that could lead to a growth in cancer cells.”

Dr Sameer Kaul

This happens at a very sub-molecular level, he adds.

Simply put, the very mechanisms that are activated when there is a lack of oxygen, can also be used for aggravation of cancer cells. If you are aware of this mechanism, you can work towards inhibiting it, and in this way — you may prevent the spread of cancer.