Scientists have successfully found a way for producing an important cancer drug ingredient in lab recently, which may bring a decrease to the cost of the related drug as its material could only be got from a plant which rarely exists.
The antitumor compound is etoposide, and its precursor form is podophyllotoxin. Etoposide is widely applied in chemotherapeutic treatment. For its biosynthetic pathway is known only partly, no effective synthesis way for its production in a large scale is accessible. Podophyllotoxin was originally found in a plant called mayapple, which blossoms in May and yields fruit in summer. The greatest limitation for the extraction of podophyllotoxin from mayapple is that the plants are rarely found and the growth speed is very slow．Thus its effectiveness against tumor, along with the market needs drove scientists to find a better production way for it.
Scientists from Stanford University firstly worked to narrow down the biosynthetic genes. They targeted 29 genes for the final determination. And then they had the 29 genes expressed in tobacco, from which six pathway enzymes were picked out as the final ones.
Together with another four previously discovered genes, the newly identified six were put to co-express still in tobacco, from which scientists constitute the etoposide aglycone pathway. Etoposide aglycone is the immediate precursor of etoposide, also a topoisomerase inhibitor with high effectiveness.
The research achieved semisynthesis production of etoposide in laboratory through tobacco, saving the effort for the cultivation of mayapple to meet the enlarging needs and reliving the time limitation on its growth. Whilst the cost of etoposide will be reduced to a great degree once the new production method can be applied out of lab in a larger scale.
Actually, there are a great number of compounds for drugs are hard to be accquired by natural extraction or lab synthesis because of their rareness and complication in chemical structure. With the success of the lab production of etoposide, more such issues will be addressed in the near future. And finally a wider range of drugs, as well as cheap access to medicines will be the greatest benefits of such advancement.
The paper of the finding has been published in the Sciences, and titled as “SIX ENZYMES FROM MAYAPPLE THAT COMPLETE THE BIOSYNTHETIC PATHWAY TO THE ETOPOSIDE AGLYCONE”.