Broken DNA is repaired with the aid of the Shieldin protein complex
New molecular DNA shield discovered with major implications for cancer treatment - health science news

Why do some breast cancer patients not respond to PARP-inhibitors or platinum-based chemotherapy? The answer lies in the newly discovered protein complex, called “Shieldin”, that shields damaged DNA, so that the broken strands of DNA can be repaired. It attaches to the broken ends of the DNA, so that the blunt ends of the DNA pieces are stuck back together. A messy but fast way to repair DNA, and used by immune cells to produce antibodies during immune responses. Importantly, cancer cells also use Shieldin, and when Shieldin is intact, PARP-inhibitors and platinum-based chemotherapy is effective. When Shieldin is mutated, the cancer cells make use of another method to repair DNA, and this sort of chemotherapy is no longer effective. The discovery of Shieldin will thus have a major impact on the treatment of breast cancers.

Read the full story: University of Toronto
Scientific publication: Nature