A molecule from frog eggs kills brain cancer

Jun 27, 2007 09:57 GMT  ·  By

Frogs are anything but intelligent; still, a synthetic version of a molecule coming from their eggs could save our big brains from cancer. The molecule called amphinase recognizes the sugary layer on the surface of tumor cell and binds to it before invading the cell and inactivating the RNA inside, killing the tumor. This would be the first treatment against brain cancer.

A team from the University of Bath (UK) and Alfacell Corporation (US) has made the first complete description of the structure and chemical properties of the amphinase. Its use could extend also to other types of cancer, other than brain ones, which currently require complex surgery and chemotherapy.

"This is a very exciting molecule. It is rather like Mother Nature's very own magic bullet for recognizing and destroying cancer cells. It is highly specific at hunting and destroying tumor cells, is easily synthesized in the laboratory and offers great hope as a therapeutic treatment of the future." said Professor Ravi Acharya, from the Department of Biology & Biochemistry at the University of Bath.

Amphinase is a type of a ribonuclease enzyme isolated from the oocytes (egg cells) of the Northern Leopard frog (Rana pipiens). Ribonucleases are universal enzymes that break down RNA molecules. Where the RNA is needed for essential functions, ribonucleases' action is suppressed by inhibitor molecules. But as amphinase, an amphibian ribonuclease, differs from mammalian ribonucleases, it can skip the mammalian inhibitor molecules to attack the RNA in cancer cells. Without functional RNA, a cell dies.

Amphinase could be injected into the required brain areas and won't affect healthy cells, as it can only recognize and attach to the sugar coating of cancer cells.

"Amphinase is in the very early stages of development, so it is likely to be several years and many trials before it could be developed into a treatment for patients. Having said that, the early data is promising and through this study we have provided the kind of information needed if approval for use is requested in the future." said Acharya.

This is the second anti-tumour ribonuclease isolated by Alfacell Corporation from Rana pipiens oocytes.

The other molecule, ONCONASE(R) (ranpirnase), is passing now through the late-stage clinical trials as a drug for unresectable malignant mesothelioma, a rare and deadly type of lung cancer, and the Phase I/II clinical trials in non-small cell lung cancer and other solid cancers. Amphinase is now in pre-clinical trails.