Green tea compound may improve cancer drugs

Behind the Headlines

Monday October 6 2014

Green tea contains a compound called epigallocatechin-3-O-gallate

Green tea originated in ancient China

"Green tea could helps [sic] scientists develop new cancer fighting drugs," the Mail Online reports. But before you rush out to the shops, in no way does this study suggest green tea can fight cancer.

Instead, research has found a compound in green tea – the catchily named Epigallocatechin-3-O-gallate (EGCG) – may help improve the effectiveness of anti-cancer drugs such as Herceptin, used in the treatment of breast and stomach cancer.

This study used nanotechnology techniques to develop a new way of packaging and carrying protein drugs by combining them with EGCG.

Scientists formed a complex compound consisting of by-products of EGCG and the protein cancer drug Herceptin.

Tests in the laboratory and mice indicated the compound might have better anti-cancer properties than standard Herceptin treatment.

This is encouraging research and may lead to improvements in delivery mechanisms for protein drugs further down the line. However, it is at a very early stage of development, so new treatments are not guaranteed.

The results from the laboratory and mice studies need to be confirmed by other research groups before the team can consider testing potential treatments in humans.

Only then will they be able to assess whether such a drug delivery system could benefit people and in what circumstances. These studies will have to pay special attention to potential side effects of the drugs.

Overall, this new nanotechnology might prove useful in several years' time, but its immediate impact is minimal.

 

A tiny guide to nanotechnology

Nanotechnology is a branch of engineering or chemistry (depending on who you speak to) which involves manipulating matter at the molecular or atomic level. This means dealing with objects that are often only a few billionths of a metre in size.

 

It now has a wide range of applications, including bandages that help stimulate the healing process, as well as new types of sunscreen lotion and – more mundanely – golf balls that fly better.

 

Some commentators predict nanotechnology will revolutionise medicine, allowing our bodies to be repaired at the cellular level.

Where did the story come from?

The study was led by researchers from the Institute of Bioengineering and Nanotechnology, Singapore, and Beth Israel Deaconess Medical Center and Harvard Medical School in the US.

It was funded by the Institute of Bioengineering and Nanotechnology and the US National Institutes of Health.

The study was published in the peer-reviewed journal, Nature Nanotechnology.

The Mail Online's coverage was broadly accurate.

 

What kind of research was this?

This laboratory-based bioengineering study developed new drug carrier technology that was then tested in mice.

Most drugs require carrier substances to ensure the active drug ingredients reach the appropriate part of the body and are released at the appropriate time.

Carriers are usually inert and are broken down in the body over time. But high quantities of some carriers can produce toxicity in the body, leading to troublesome side effects.

This study aimed to improve current drug carriers by developing a carrier that was easily metabolised in the body, and may even do some good by itself.

The researchers said green tea extract was used because previous research indicated it had anti-cancer effects, as well as protective effects on the nervous system and DNA.

Many new technologies are tested in mice first as – despite the difference in size – they have a similar biology to humans. However, some things work differently in mice and men, so any positive findings in mice would not automatically apply to humans.

 

What did the research involve?

The research involved developing a new biological compound to carry cancer drugs based on derivatives (by-products) of one of the main ingredients in green tea, called Epigallocatechin-3-O-gallate (EGCG).

The research team joined EGCG derivatives with various anti-cancer proteins to form what are known as nanocomplexes – intricately engineered combinations of proteins.

One of the nanocomplexes comprised the anti-cancer protein Herceptin bundled with an EGCG derivative, forming a core, and a separate EGCG-derived shell around the outside.

They injected this into mice with cancer to see if the Herceptin-EGCG carrier nanocomplex was more or less effective at fighting tumour cells than "free" Herceptin alone.

 

What were the basic results?

The team found they were able to make stable nanocomplexes incorporating anti-cancer proteins with EGCG derivatives.

When the Herceptin-EGCG complex was injected into mice with cancer, it was better at targeting tumour cells (it had better "selectivity") and reducing their growth, and lasted longer in the blood than free Herceptin.

This complex also displayed better anti-cancer properties when tested on human breast cancer cells in the laboratory.

The researchers also coupled ECGC derivatives with another protein called interferon α-2a, which is used in combination with chemotherapy and radiation as a cancer treatment. This nanocomplex was better at limiting cancer cell growth than free interferon α-2a.

 

How did the researchers interpret the results?

The researchers stated they developed and characterised a new green tea-based mechanism for protein drug delivery where the carrier itself displays anti-cancer effects.

They said the nanocomplex effectively protected the protein drugs against many obstacles from the point of administration to the required delivery sites.

They concluded that, "The combined therapeutic effects of the green tea-based carrier and the protein drug showed greater anti-cancer effect than the free protein."

 

Conclusion

This study developed a new way of packaging and carrying protein drugs by combining them with a green tea extract called Epigallocatechin-3-O-gallate (EGCG), which itself may have anti-cancer properties.

They formed a complex between derivatives of EGCG and the protein cancer drug Herceptin. Tests in the laboratory and in mice indicated it might have better anti-cancer properties than non-complexed free Herceptin.

This is encouraging research and may lead to improvements in delivery mechanisms for protein drugs further down the line.

But this research remains at a very early stage of development. The results from the laboratory and mice studies need to be confirmed by other research groups before the team can consider testing potential treatments in humans.

Only then will they be able to assess whether such a drug delivery system could benefit people. These further studies will have to pay special attention to potential side effects of the drugs.

Green tea extracts are often the subject of news headlines, often in the very early stages of drug development.

Other claims made about green tea include how it can help prevent prostate cancer, reduce stroke riskboost the ability of the brain, and help ward off Alzheimer's disease.

Some people have even gone as far as claiming the beverage is a “"superfood". Many of these claims are not backed by robust evidence, however.

Overall, this new nanotechnology might prove useful in many years' time, but its immediate impact is minimal.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Analysis by Bazian

Edited by NHS Choices

Links to the headlines

Green tea could helps scientists develop new cancer fighting drugs. Daily Mail, October 5 2014

Links to the science

Chung JE, Tan S, Gao SJ, et al. Self-assembled micellar nanocomplexes comprising green tea catechin derivatives and protein drugs for cancer therapy. Nature Nanotechnology. Published online October 5 2014

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