A new study could lead to a breakthrough against cancer in the form of immunotherapy, which will exploit a unique immune system weapon in the battle against cancer: naturally produced antibodies.
Antibodies are proteins that neutralize specific threats. Other recent studies have found that naturally occurring antibodies have often been discovered in cancerous tumors, but their purpose was unknown – they might very well have been generated by the body, without any relation to the cancer itself.
Indirect evidence, however, had suggested that they do offer some sort of antitumor benefit: patients who survive longer than others and are more responsive to anticancer drugs were found to have higher concentrations of the antibody-producing B cells in their tumors.
Still, there was no way of determining whether these cells, and the antibodies they produce, contribute to improved survival, and if so, how they accomplish that.
The new findings, published in the journal Cell, managed to identify one molecule out of the thousands of proteins in cancer cells that is targeted by the newly identified antibodies: the membrane-bound protease enzyme called MMP14 (MT1-MMP).
In a healthy person, this scissor-like enzyme plays important role in remodeling tissues, for example during regeneration or wound healing.
In cancer, however, it operates in the tumor’s microenvironment and spreads out of control, cutting through the matrix around the cancer cells and thus helping them invade the surrounding tissue and spread to other organs, leading to deadly metastasis.
Researchers at the Weizmann Institute of Science found that the ovarian tumors in their study contained abnormally high levels of the MMP14 enzyme.
“We’ve now shown that the immune systems of cancer patients can produce antibodies against tumors,” says Prof. Ziv Shulman, who headed the Weizmann research team together with Prof. Irit Sagi.
“These natural antibodies appear to have an unrealized therapeutic potential,” said Sagi. “More research is needed in order to apply them in future therapies or as diagnosis reagents.”
The research paves the way for a novel approach to developing cancer immunotherapies, one that will make use of natural anti-tumor antibodies. Although the scientists focused on ovarian cancer, they said it could apply to other types of cancer as well.