• Question: How would shutting down particular enzymes help treat cancer?

    Asked by anon-196027 to Fiona on 8 Mar 2019.
    • Photo: Fiona Scott

      Fiona Scott answered on 8 Mar 2019:


      Some enzymes carry out critical jobs in cancer cells and keep them alive so if we shut them down the cell can’t survive.

      For example. We have two enzymes in our body called PARP and BRCA that repair our DNA when it gets damaged. In certain types of breast cancer cell, the BRCA enzyme is not present so only PARP is around to repair DNA. Lots of drugs that shut down PARP work really well to treat breast cancer because without PARP and BRCA working, a cancer cell can’t repair its DNA well enough to stay alive and so it dies. Olaparib was the first PARP inhibitor and is used to treat breast and ovarian cancers that don’t have BRCA enzymes.

      Other enzymes help prevent cancer. These are called tumour suppresor enzymes, the most famous of which is called p53. In a lot of cancers p53 is missing.

      Understanding the differences in what enzymes are found in cancer cells vs. healthy cells, and in what number (sometimes all the enzymes are the same but there are a lot more of a particular kind which makes the cell act as a cancer cell) helps us to give “targeted therapies” for cancer that specifically affect cancer cells and not healthy ones.

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