VERY ingenious weapon to treat women’s cancer

SPERM that’s been loaded with chemotherapy drugs could be used to fight cancer in women.

The guided missile technique involves using drug-treated sperm to deliver the medicines to tumours deep inside the body.

The revolutionary treatment could help thousands of women affected by cancers of the reproductive system, which can be reached by the drugcarrying sperm. Cancer of the womb kills more than 2,000 women a year in the UK and cervical cancer claims the lives of around 900.

Treatment includes chemotherapy to try to poison the cancer cells before they spread.

But this also damages healthy cells. For years, scientists have been exploring ways to deliver toxic anti- cancer medicines directly to tumour sites, leaving healthy tissues unscathed.

One method used bacteria as a form of transport, as they can penetrate the body easily.

But though the technique was relatively effective at getting chemotherapy drugs deep inside the body, the immune system often destroyed the bacteria (which it saw as an invader) before they reached their destination.

Using sperm gets round this problem because, even though it is ‘foreign’, it does not get attacked by a woman’s immune system.

This is thought to be because, on its surface, sperm carries certain sugar molecules — glycoproteins — which are recognised by all human immune systems, allowing them safe passage through the female body.

Scientists at the Institute for Integrative Nanosciences in Dresden, Germany, chose to experiment with sperm because of its ability to propel itself through the reproductive tract.

Sperm move forwards by thrashing their long tail — or flagellum — to reach the fallopian tubes and try to fertilise an egg.

Researchers wondered if this could be utilised to steer drugcarrying sperm to hard-to-reach tumours in women’s reproductive tracts. They’re perfecting the technique to ensure they can target tumours accurately so that pregnancy won’t happen.

In a recent study, scientists began by soaking individual sperm in a chemotherapy drug called doxorubicin for several hours. Doxorubicin is a commonly used drug that treats many cancers and works by blocking an enzyme, called topoisomerase 2, which cancer cells need to grow.

Next they covered each sperm in a miniature metal harness, no bigger than a pinhead, which was coated with an iron solution.

Once the sperm is injected into the vagina, it automatically propels itself in the direction of the cervix. But the iron solution means scientists can steer the cargo exactly where it needs to go in the body, using a powerful magnet held over the pelvis and ultrasound imaging to navigate.

Once it reaches the tumour, the toxic sperm is able to easily penetrate malignant cells, in much the same way as it fuses with an egg during fertilisation.

The harness has four ‘legs’ that lock on to the cancer cell and, on impact, the sperm and the drug burst through to the outer membrane of the tumour.

This allows the medicine to penetrate the cancer cell, killing it. The harness is broken down and flushed out of the body.

So far, the technique has been tested in the lab using bull sperm, which closely resembles human BUT sperm, and cancer cells in a dish. the results, uploaded to the online database arXiv, showed even though the iron harness halved the speed at which sperm normally travel, they were still able to find the cancer cells accurately and destroy them.

Now the team plans to test the therapy on human sperm before extending it to cancer patients, possibly within five years.

Tracie Miles, cancer information nurse at The Eve Appeal — a charity that helps women with cervical, ovarian or womb conditions — says the technique could be used to deliver other cancer drugs in future.

‘This novel form of drug delivery harnesses nature’s own ingenuity in using sperm as a potential treatment for cancers.’