Navigating prostate cancer in the current unrest

Immunotherapy has revolutionised the way we treat many cancers. It encourages the body's own defence mechanisms - the immune system - to target the cancer, either alone or in combination with other treatments.

However, prostate cancer is different. Unlike other cancers, it rarely responds to immunotherapy, leaving fewer treatment options for men with the disease.

That could soon change thanks to research we've funded at the University of Sheffield, which has shown that it's possible to deliver immunotherapy directly to prostate cancer cells using microscopic containers (nanoparticles).

The researchers found that the nanoparticle treatment could help men live longer, extending the amount of time it took before their prostate cancer became resistant to hormone therapy.

The study, published in the Journal for Immunotherapy of Cancer, was funded as part of our Research Innovation Awards programme, which has seen £20m invested in exciting new research over the last 10 years.

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For thousands of men with prostate cancer, hormone therapy is a powerful, first-line treatment. However, for some men, their cancer can become resistant to it, enabling the disease to grow, spread and become harder to treat.

If immunotherapy could extend the effectiveness of hormone therapy, it could offer these men a longer, healthier life.

Looking at tumour samples from both mice and men, the Sheffield team studied how immune cells inside prostate tumours behave during hormone therapy, using a technique that attaches fluorescent markers to cells so they can be seen under a microscope.

They found that a type of white blood cell, called a macrophage, collects in large numbers around tumour blood vessels during the treatment – making them well-placed targets for immunotherapy.

The researchers then developed nanoparticles that could deliver a drug to these immune cells specifically. These nanoparticles act a bit like targeted missiles – microscopic spheres with a detector on the outside that looks for macrophages, and a space inside to fit the immunotherapy drug, keeping it locked away until it reaches the right location.

The drug itself makes the macrophages produce a signal that encourages other immune cells, called T cells, to kill the nearby cancer cells.

When the treatment was combined with hormone therapy, the tumours took longer to become resistant.

The team now hopes to take the treatment from the lab into clinical trials, to see whether it helps extend the lives of men receiving hormone therapy. Since the same immune cells were found to surround blood vessels in both mice and men, the team believes the treatment has a good chance of helping men with prostate cancer.