Breast cancer cells recycle ammonia waste as fuel

According to the latest research, breast cancer cells recycle ammonia, a waste byproduct of cell metabolism, and use it as a source of nitrogen to fuel tumor growth. The presence of ammonia accelerates proliferation of cultured breast cancer cells, while suppressing ammonia metabolism can stunt tumor growth in mice.

This showed the biological role of ammonia in cancer and may inform the design of new therapeutic strategies to slow tumor growth. Ammonia is toxic for breast cancer cells, it could be used to feed tumors by serving as a source for the building blocks that tumors need to grow.

Cancer cells consume nutrients voraciously and generate excess metabolic waste. One such byproduct, ammonia, is normally transported in blood vessels to the liver, where it is converted into less toxic substances and excreted from the body as urea.Tumors have few blood vessels, and as a result, ammonia accumulates in the tumor's local environment at concentrations that would be toxic for many cells.

When glutamine is broken down during cell metabolism, ammonia containing nitrogen is released as a byproduct.
Tracing the fate of this marked ammonia, the researchers examined different cellular metabolites in breast cancer cells and in human tumors transplanted into mice. They found cancer cells recycled ammonia with high efficiency, incorporating it into numerous components-primarily the amino acid glutamate, a fundamental building block for proteins, as well as its derivatives.

Higher concentrations of ammonia appeared to accelerate the growth of lab-grown breast cancer cells. Ammonia exposed cells doubled up seven hours faster than cells grown without ammonia. In 3-D cultures-a technique that allows cells to divide in all directions as they do inside the body, ammonia exposure increased the number of cells and surface area of cell clusters by up to 50 percent compared with cells grown without ammonia.

Ammonia also accelerated tumor growth and proliferation in mice with transplanted human breast cancer. When the team blocked the activity of glutamate dehydrogenase GDH-an enzyme that specifically assimilates ammonia to carry out its function, tumor growth slowed significantly compared to tumors with intact GDH activity. Repressing ammonia metabolism stunts tumor growth in mice.
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Diet rich in sugar multiply cancer in the body

A sugar rich diet may be fuelling various forms of cancer, tumours thrive off sugar, using it as energy to mutate and spread across the body.

Now scientists have shown one type of cancer - which can be found in the lungs, head and neck, oesophagus and cervix - has more of a sweet tooth than others.

Squamous cell carcinoma (SqCC) was more dependent on sugar to grow,
This form of the disease used higher levels of a protein that carries glucose to cells to enable them to multiply.

Excessive sugar consumption can leads to diabetes and cancer, because some cancers dependent on sugar to grow.
Without a sufficient supply of the sugar, cells in the body can not function properly.

Cancer Research UK make clear that cancerous cells aren't just dependent on sugar for their growth, as they rely on amino acids and fats also.

The new findings came after researchers looked into the differences between two major subtypes of non-small cell lung cancer - adenocarcinoma (ADC) and SqCC.

About one quarter of all lung cancers are SqCC, which has been difficult to treat with targeted therapies.
The study first tapped into The Cancer Genome Atlas, which maps information about 33 types of cancer gathered from more than 11,000 patients.

Based on that data, it found a protein responsible for transporting glucose into cells was present in significantly higher levels in lung SqCC than in lung ADC.

The protein, called glucose transporter 1, or GLUT1, takes up glucose into cells, where the sugar provides a fundamental energy source and fuels cell metabolism.
GLUT1 is also necessary for normal cell function.