DNA-PK participates in pre-rRNA biogenesis independent of DNA double-strand break repair.

Nucleic Acids Res

Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.

Published: June 2024

Although DNA-PK inhibitors (DNA-PK-i) have been applied in clinical trials for cancer treatment, the biomarkers and mechanism of action of DNA-PK-i in tumor cell suppression remain unclear. Here, we observed that a low dose of DNA-PK-i and PARP inhibitor (PARP-i) synthetically suppresses BRCA-deficient tumor cells without inducing DNA double-strand breaks (DSBs). Instead, we found that a fraction of DNA-PK localized inside of nucleoli, where we did not observe obvious DSBs. Moreover, the Ku proteins recognize pre-rRNA that facilitates DNA-PKcs autophosphorylation independent of DNA damage. Ribosomal proteins are also phosphorylated by DNA-PK, which regulates pre-rRNA biogenesis. In addition, DNA-PK-i acts together with PARP-i to suppress pre-rRNA biogenesis and tumor cell growth. Collectively, our studies reveal a DNA damage repair-independent role of DNA-PK-i in tumor suppression.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11194077PMC
http://dx.doi.org/10.1093/nar/gkae316DOI Listing

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