201. K48-linked deubiquitination of VGLL4 by USP15 enhances the efficacy of tumor immunotherapy in triple-negative breast cancer.
- Author
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Wang, Xuehui, Deng, Xiaochong, Hu, Jiashu, Zheng, Wenfang, Ye, Danrong, Zhou, Xiqian, and Fang, Lin
- Subjects
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TRIPLE-negative breast cancer , *IMMUNE checkpoint proteins , *IMMUNOTHERAPY , *DEUBIQUITINATING enzymes , *PROGRAMMED cell death 1 receptors - Abstract
Immunotherapy based on PD-1/PD-L1 antagonists has been demonstrated to be efficacious in inducing tumor remission in patients with triple-negative breast cancer (TNBC). However, tumor immune evasion caused by the PD-1/PD-L1 pathway inhibits the immunotherapeutic effect of PD-1/PD-L1 inhibitors against TNBC. Therefore, identifying potential targets for blocking the PD-1/PD-L1 pathway is a compelling strategy for TNBC treatment. Here, we discovered that VGLL4 could inhibit PD-L1 transcription by suppressing STAT3 activation, thereby enhancing the efficacy of anti-PD-1 antibody immunotherapy in TNBC. Low expression of USP15, a deubiquitinating enzyme of VGLL4, was associated with reduced CD8+ T cell infiltration and poor prognosis in TNBC patients. USP15 was found to inhibit PD-L1 transcription, leading to increased CD8+ T cell infiltration and thus enhancing the efficacy of TNBC immunotherapy. Furthermore, SART3 regulated VGLL4 stability and PD-L1 transcription by influencing the nuclear translocation of USP15. In conclusion, our study provides new insights into the biological regulation of PD-L1, identifies a previously unrecognized regulator of this critical immune checkpoint, and highlights potential therapeutic targets for overcoming immune evasion in TNBC. • VGLL4 enhances the efficacy of anti-PD-1 antibody immunotherapy for TNBC by inhibiting PD-L1 transcription. • The C-terminal of USP15 is responsible for its interaction with TDU domains in VGLL4. • USP15 removes the K48-linked ubiquitination of VGLL4 and stabilizes VGLL4. • Low expression of USP15 is accompanied by reduced CD8+ T cell infiltration and poor prognosis in TNBC patients. • USP15 enhances the efficacy of anti-PD-1 antibody immunotherapy for TNBC. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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