Malaria parasite helps fight chemotherapy-resistant cancer, UBC research finds
Scientists have found one malaria protein is especially effective in carrying toxin directly to bladder cells to kill them
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A malaria parasite may hold the key to treat bladder cancer in patients who only have a 50 per cent change of responding positively to traditional chemotherapy treatments.
UBC researchers found the treatment, a combination of a malaria protein with a marine sponge toxin, was 80 per cent effective on mice – the other 20 per cent of mice died within 70 days from bladder cancer, a disease that kills more than 2,000 Canadians every year.
It’s the latest development in the cancer research trend that has researchers looking outside of chemotherapy for innovative treatment options.
“We can take a protein from one devastating disease and repurpose it to treat another devastating disease,” said Mads Daugaard, UBC professor of urologic science.
His team found that a specific protein in the malaria parasite, VAR2CSA, was especially good at binding to the host’s placenta. This results in 200,000 newborn deaths a year but Daugaard thought he could take advantage of this characteristic because that same protein attaches itself to bladder cancer cells too.
“We thought we might be able to take advantage of that protein from the malaria parasite and simply repurpose it to bind tumour cells instead,” he said.
The protein is good at binding to both placenta and cancer cells because the two have many similarities, despite the reality that one sustains life while the other takes it away.
For instance, placenta cells proliferate rapidly during pregnancy to become a 500-gram organ in only 40 weeks, according to Daugaard. Those cells also have the ability to attach itself to neighbouring tissue – the uterus. Cancer cells display the same “dramatic and rapid” behaviour of growing and attaching itself to its host, explained Daugaard.
His team has turned the protein into a cancer-fighting weapon by combining it with hemiasterlin toxin, one of the most poisonous molecules in the world, found in sea sponges. The idea is the protein will carry the toxin to the bladder and kill the cancer.
“You could say we combined something from a sponge and a malaria parasite to develop a weapon against [chemotherapy]-resistant bladder cancer.”
The technique appears to have worked on mice and now the goal is to scale up drug production so the team can conduct clinical trials.
Daugaard says this treatment has the potential to save thousands of lives, because bladder cancer is the fifth most common cancer in Western countries and the current chemotherapy-surgery treatment only works on 1 out of every 2 patients. About 8,700 Canadians are diagnosed with bladder cancer every year, according to the Canadian Cancer Society. Those who don’t respond to chemotherapy face a grim five-year prognosis, according to Daugaard.
Bladder cancer is also the most expensive cancer to treat on a per patient basis, he said. That’s because bladder cancer can only be diagnosed via biopsy. In contrast, doctors can spot markers for other types of cancers like prostate cancer in a simple blood test.
“There is a clinical need to develop new second-line therapies in bladder cancer but there is also an economic need,” he said.
Daugaard says this malaria-inspired treatment could be available for bladder cancer patients in as early as 2020.