Small molecule found that 'fights Kaposi's sarcoma'
A molecule found in the urine of pregnant women blocks the growth of a variety of cancers, including Kaposi's sarcoma - the AIDS-related cancer that currently has no cure - according to scientists at the University of Montreal in Canada.
"Clinical grade" hCG - where it is either crude or just partially purified - is used in male hormone treatment and in medications for female infertility. In 1995, studies published in Nature and The Lancet reported that clinical grade hCG extracted from pregnant women's urine was effective at shrinking Kaposi's sarcomas. However, this claim was later retracted by the authors.
Before this retraction, however, Tony Antakly, PhD, and his team at the University of Montreal had already begun examining what anti-cancer effects hCG may have. They tested purified hCG in Kaposi's sarcoma cells, but found no cancer-fighting effects, which led the team to wonder if the purification process removes the anti-cancer properties.
Medical News Today asked Dr. Antakly how the team's work on hCG had been influenced by other scientists losing faith in the idea of the hormone having anti-cancer properties. He responded:
In 1995, studies reported that clinical grade hCG extracted from pregnant women's urine was effective at shrinking Kaposi's sarcomas. This was later retracted.
"We knew then that it was worth identifying the right molecule because of its potential application as a therapeutic agent that could inhibit Kaposi's sarcoma, HIV and maybe other cancers as well. We took a systematic experimental approach and explored every avenue with this objective in mind."
"The material conditions were difficult and funding was low but we kept patiently working," he added. "In addition, every time the active fraction was extensively purified, the active molecule 'disappeared.' So, we had to change strategy and eventually the right conditions were found."
They team did not give up. They refined their search, looking more closely at small molecular weight factors in clinical grade hCG. To find the active molecule - or part of a molecule - they systematically split the molecules in these "hCG-like inhibitory products" (HIP), performing biological assays and chemical characterization each time.
Cancer-fighting molecule is a small, transformative metabolite
The team found their answer in a small metabolite that is the product of a larger hCG molecule carried in blood and urine. This HIP metabolite "piggybacks" on the larger hCG molecule, so when hCG is excessively purified in the laboratory, the metabolite "loses its ride" and disappears.
To fight cancer, the metabolite transforms into a potent bioactive metabolite that can affect living tissue. "We don't know if it changes only when needed," Antakly says. "Perhaps in cancer, it changes to fight the disease."
- In AIDS patients, Kaposi's sarcoma is caused by an interaction between HIV and human herpesvirus-8
- Before the AIDS epidemic, Kaposi's sarcoma was seen mainly in elderly Italian and Jewish men
- According to the American Cancer Society, more than 90% of the population in some regions of Africa show signs of KHSV infection.
When exposed to Kaposi's sarcoma cells in the laboratory, Antakly says the HIP metabolite "wiped out the cancer cells completely."
Antakly says his team has found that HIP purified from clinical grade hCG is both safe to use and has anti-cancer properties. Currently, they are developing a synthetic replica of the HIP metabolite that could be used in treatment. However, it is too soon to know yet whether this synthetic metabolite will be safe and effective at high doses in treating patients with cancer.
The team presented their results at the joint meeting of the International Society of Endocrinology and The Endocrine Society: ICE/ENDO 2014 in Chicago, IL.
Earlier this year, scientists from the University of Texas published a study in PLOS Pathogens that offered an explanation of the mechanism behind Kaposi's sarcoma, which has not previously been well-understood.
The researchers claimed that a cluster of viral microRNA molecules are responsible for turning healthy cells into cells infected with Kaposi's sarcoma-associated herpesvirus (KSHV). Previously, scientists had been unable to study the virus, because cells infected with KSHV die before being turned into cancer cells.
Written by David McNamee
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