Killing cancer

Killing cancer cells is at the heart of Professor Marianne Cronjé’s pioneering research at the University of Johannesburg (UJ) department of biochemistry.

“But we’re years away from a cancer cure,” she says.

Since the news broke about a “silver bullet” that could, if clinical trials are successful in years to come, help prevent cancer cells from reproducing in their deadly indefinite manner, Cronjé has been inundated with emails and calls from desperate cancer patients.

“But we’re at least 10 to 15 years away from a successful, commercial drug,” she explains.

We’re sitting in her small head of biochemistry department office at UJ.

She’s just returned from the annual meeting of the International Cell Death Society in Seoul, South Korea, and her calm demeanour belies the pressure she’s under.

It’s no wonder that in a world where nearly everyone knows someone fighting cancer, the results that Cronjé and her fellow researchers have achieved, after a decade of labour, are generating huge interest.

Apart from the obvious life-saving potential of the research, the silver-based anti-cancer drugs could also mean smaller doses of them, and fewer adverse side-effects, including lower toxicity levels.

There are three cancers in particular, called UJ3, that Cronjé and her team hope their work will result in a drug being created to combat.

They are breast, oesophageal and melanoma (skin) cancer.

“I’ve always been interested in the cell death process,” says the professor, as she explains that about 6 billion cells are recycled daily in our bodies “because they no longer have a function.”

It’s a form of cell suicide – called apoptosis – that is a neat and tidy way of cleaning up cells.

Cancer cells have, however, developed the ability to avoid apoptosis, which means they don’t die but rather “they become immortal”.

“They can evade your immune surveillance system, proliferate and eventually form a tumour.”

It is the tumour that kills.

Cronjé, who obtained her PhD in biochemistry from Rand Afrikaans University, now UJ, in 2002, moved into human cell research about 14 years ago.

She was intrigued by what made cancer cells so resistant to natural cell death and wondered “how we could reactivate the apoptosis process in cancer cells with the aim of developing anti-cancer treatments”.

It was over a glass of wine with her friends, UJ chemistry professor Reinout Meijboom and his wife Professor Lizelle Piater, that the topic of silver phosphines came up.

“He was interested in the compounds from a pure chemistry perspective and I asked him for a few samples so we could test if they might induce cancer cell death,” Cronjé says.

Meijboom didn’t think silver complexes would work but he was happy to give Cronjé a few.

One of her PhD students called her excitedly one day to look through the microscope at what was a “really distinctive form of cell death”.

Cronjé suggested the student next use the complexes on normal cells, “and it didn’t affect them”.

“That was our first indication that there was something special about the silver compounds.”

Now, 10 years on, Cronjé is “pretty confident that we have a unique anti-cancer therapy”.

Her team has done extensive in vitro testing of the compounds, and animal toxicity studies show rats have seemingly tolerated it well.

Cronjé chooses her words with care, saying they need to test what is now basically a powder on a shelf to ascertain how it could be formulated for use in clinical trials.

“There is still a great deal of work to be done.”

The lifeblood of researchers is papers they write about their findings.

“We have a saying – publish or perish.”

Cronjé’s team published several peer-reviewed papers, and recently an industrious UJ public relations officer wrote a feature about the biochemistry department’s excellent findings.

The publicity reached the general media and soon television, radio and print journalists were beating their way to the professor’s door.

“It’s been a bit invasive because most academics are camera-shy. We’re not in this for fame and glory. We’re in it to get questions answered.”

The pharmaceutical industry is a hugely competitive environment and Cronjé has no idea where that might lead her and UJ.

However, various patent applications have been registered in Australia, India, Canada, Europe, the US and South Africa.

Cronjé, who is married with two sons in their twenties, says the sad stories she hears about cancer sufferers make her even more determined to continue with the research.

“The science has been completely solid. We’ve expected to fail again and again. We’ve thought things wouldn’t work but they did.”

A new anti-cancer drug is met, she says, with cynicism from “everyone except the desperate cancer patients”.

Her dream is for a reasonably priced drug that could change the lives of thousands of poorly resourced South Africans.