This is a first-in-class drug, meaning it is the first drug developed from a new technology created by Tamir Biotechnology, Inc. It is currently being tested in clinical trials as a treatment for certain cancers, including mesothelioma. It has not yet been approved by the Food and Drug Administration (FDA) for use.
The major advantage of this drug is that it targets cancer cells without harming normal cells. It triggers apoptosis, or programmed cell death, through multiple mechanisms of action.
Ranpirnase is a type of enzyme called a nuclease. These enzymes breakdown the bonds between certain subunits of nucleic acids, which are part of a cell’s DNA. Ranpirnase is classified as a ribonuclease, meaning a specific type of nuclease that breaks down RNA. Ranpirnase is found in the immature egg cell of the Northern Leopard Frog, a native of North America.
The enzyme is made up of a single peptide chain which contains one-hundred and four amino acids, and its molecular mass is approximately twelve-thousand daltons. A dalton is a unit that is used to measure an object’s mass on an atomic or molecular scale.
Ranpirnase starts to work by first binding to the receptors on the surface of tumor cells. It is then taken into the cells by endocytosis, the process through which cells absorb proteins that are outside their walls by engulfing the proteins with their cell membranes. At this point, the ranpirnase reaches the cytosol, the fluid inside cells. It avoids the endogenous ribonuclease inhibitor, a protein whose job is to stop the activity of the ribonuclease enzyme. It is then able to start breaking down a number of different types of RNA within the cells, especially tRNA or Transfer RNA.
Transfer RNA transfers the necessary active amino acid to the site where the ribosome is making protein, But this is only the beginning of a multi-step process that leads to the copying of the DNA into messenger RNA (mRNA), which is decoded by the ribosome into a specific sequence of amino acids. Those amino acids are assembled into a protein and the proteins that are made from each sequence become the building blocks from which new cells are created.
By breaking down Transfer RNA, ranpirnase stops the protein-making process, preventing cells from reproducing and proliferating. In addition, it leads to apoptosis or programmed cell death of the cancerous cells.
The drug is primarily designed to use in combination with other chemotherapy drugs to increase their effectiveness, or to make them effective if they weren’t so in the past. It can also be used in patients with a good response to their current treatment so that the dosage can be reduced, resulting in a lessening of adverse side effects of the current therapy.
It is the first ribonuclease protein drug and one of the first drugs created from embryonic stem cells to have reached Phase III clinical trials in humans. However, these trials are in their beginning stages, so very little is known about any adverse side effects the drug may have.