2. Academic Validation
  3. The novel β-TrCP protein isoform hidden in circular RNA confers trastuzumab resistance in HER2-positive breast cancer

The novel β-TrCP protein isoform hidden in circular RNA confers trastuzumab resistance in HER2-positive breast cancer

  • Redox Biol. 2023 Sep 28:67:102896. doi: 10.1016/j.redox.2023.102896.
Shengting Wang 1,  Yufang Wang 1,  Qian Li 1,  Xiaoming Li 1,  Xinghua Feng 1,  Kaixuan Zeng 2
Affiliations

Affiliations

  • 1 Clinical Medical Center, Xi'an Peihua University, Xi'an, 710125, Shaanxi, China.
  • 2 Precision Medical Research Institute, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710000, Shaanxi, China. Electronic address: [email protected].
PMID: 37783059 DOI: 10.1016/j.redox.2023.102896
Abstract

Trastuzumab notably improves the outcome of human epidermal growth factor receptor 2 (HER2)-positive breast Cancer patients, however, resistance to trastuzumab remains a major hurdle to clinical treatment. In the present study, we identify a circular RNA intimately linked to trastuzumab resistance. circ-β-TrCP, derived from the back-splicing of β-TrCP exon 7 and 13, confers trastuzumab resistance by regulating NRF2-mediated antioxidant pathway in a KEAP1-independent manner. Concretely, circ-β-TrCP encodes a novel truncated 343-amino acid peptide located in the nucleus, referred as β-TrCP-343aa, which competitively binds to NRF2, blocks SCFβ-TrCP-mediated NRF2 proteasomal degradation, and this protective effect of β-TrCP-343aa on NRF2 protein requires GSK3 activity. Subsequently, the elevated NRF2 transcriptionally upregulates a cohort of antioxidant genes, giving rise to trastuzumab resistance. Moreover, the translation ability of circ-β-TrCP is inhibited by eIF3j under both basal and oxidative stress conditions, and eIF3j is transcriptionally repressed by NRF2, thus forming a positive feedback circuit between β-TrCP-343aa and NRF2, expediting trastuzumab resistance. Collectively, our data demonstrate that circ-β-TrCP-encoded β-TrCP protein isoform drives HER2-targeted therapy resistance in a NRF2-dependent manner, which provides potential therapeutic targets for overcoming trastuzumab resistance.

Keywords

Circular RNA; NRF2; Protein coding; Protein degradation; Trastuzumab resistance.

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