Published in the journal Cellular Oncology, the study reports that the XRCC4 protein can be glutarylated, a modification associated with the sensitization of breast cancer cells to PARP inhibitors.

The research was published on August 31, 2026, and is available as an open access article. The authors utilized multi-omics datasets to delineate the characteristics of XRCC4 in breast cancer, providing a comprehensive view of its role in the disease context.

In vitro experiments showed that when XRCC4 is overexpressed, it promotes the proliferation of breast cancer cells. Conversely, when the expression of XRCC4 is knocked down, cell proliferation is inhibited.

The central finding of the research is that the XRCC4 protein can be glutarylated. Glutarylation is described as a newly identified form of protein acylation that has been linked to the regulation of tumor metabolism. However, the specific role of glutarylation in breast cancer had previously been unclear. The study used bioinformatics predictions, immunofluorescence, and co-immunoprecipitation experiments to confirm the glutarylation of XRCC4.

Further mechanistic analysis revealed that the deglutarylase SIRT5 binds to XRCC4 in the cytoplasm.

The study also investigated the downstream effects of XRCC4 knockdown. The findings showed that reducing XRCC4 levels promotes autophagy by inhibiting the p-mTOR/p-ULK1 pathway.

The study concludes that XRCC4 glutarylation enhances the sensitivity of breast cancer to PARP inhibitors through the inhibition of mTOR activity and the promotion of autophagy. The authors state that this mechanism offers additional options for maintenance therapy utilizing PARP inhibitors in breast cancer treatment.

Subject of Research: Mechanism of XRCC4 glutarylation in breast cancer response to PARP inhibitors

Article Title: XRCC4 glutarylation promotes its degradation to sensitize breast cancer cells to PARP inhibitors

Article References: Du, X., Yang, X., Huang, Y., Li, L., Hong, C., & Wang, Q. (2026). XRCC4 glutarylation promotes its degradation to sensitize breast cancer cells to PARP inhibitors. Cellular Oncology. https://doi.org/10.1007/s13402-026-01286-3

Image Credits: AI Generated

DOI: 10.1007/s13402-026-01286-3

Keywords: breast cancer, PARP inhibitors, XRCC4, glutarylation, protein degradation, SIRT5, autophagy, mTOR pathway, Cellular Oncology, cancer therapy, promotes, degradation