Targeting the NR4A3-RNF139-ATF6 pathway as a therapeutic and diagnostic strategy in bladder cancer
1Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China.
Background:
Bladder cancer (BCa) is a prevalent malignancy with high recurrence and metastasis rates. Nuclear receptor subfamily 4 group A member 3 (NR4A3), a member of the orphan nuclear receptor superfamily, is implicated in various cancers, but its functional role and mechanisms in BCa have not been well understood. This study aimed to explore the functional significance and diagnostic value of NR4A3 in BCa, with a focus on its regulation of endoplasmic reticulum (ER) stress and anoikis sensitivity via ATF6 and RNF139.
Methods:
NR4A3 expression in BCa cell lines was assessed by qRT-PCR and Western blot. Gain-of-function assays were performed to evaluate cell proliferation, apoptosis, and anoikis sensitivity in vitro. ER stress markers and ATF6 degradation were examined by immunoblotting, cycloheximide chase, and ubiquitination assays. The role of RNF139 and its regulation by NR4A3 via KLF2 and KLF4 were determined via various biological assays. In vivo tumorigenesis was assessed using a xenograft mouse model. Additionally, the diagnostic performance of NR4A3 was evaluated in 100 clinical patients using serum ELISA and color Doppler ultrasound.
Results:
NR4A3 was downregulated in BCa cells, and its overexpression suppressed cell proliferation, colony formation and promoted apoptosis and anoikis sensitivity. Mechanistically, NR4A3 inhibited ER stress by promoting ATF6 ubiquitination and degradation via transcriptional activation of RNF139 through KLF2 and KLF4. RNF139 directly interacted with ATF6 and mediated its ubiquitination at lysine 152. In vivo, NR4A3 overexpression inhibited tumor growth. Clinically, combining color Doppler ultrasound with serum NR4A3 levels significantly improved diagnostic accuracy for BCa (AUC = 0.986).
Conclusion:
NR4A3 suppresses BCa progression via the KLF2/4-RNF139-ATF6 axis and enhances diagnostic efficacy when combined with ultrasound imaging.
Insights
Nuclear receptor subfamily 4 group A member 3 (NR4A3) suppresses bladder cancer (BCa) progression by inhibiting endoplasmic reticulum stress. Combining NR4A3 detection with ultrasound improves BCa diagnosis.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Diagnostics
Background:
- Bladder cancer (BCa) is a common malignancy with high recurrence and metastasis rates.
- The role of Nuclear Receptor Subfamily 4 Group A Member 3 (NR4A3) in BCa pathogenesis and its underlying mechanisms remain unclear.
- This study investigates NR4A3's function in BCa, focusing on endoplasmic reticulum (ER) stress and anoikis signaling.
Purpose of the Study:
- To elucidate the functional role of NR4A3 in bladder cancer progression.
- To explore the regulatory mechanisms of NR4A3 involving ER stress and anoikis.
- To evaluate the diagnostic value of NR4A3 in bladder cancer patients.
Main Methods:
- NR4A3 expression analysis in BCa cell lines using qRT-PCR and Western blot.
- In vitro gain-of-function assays to assess proliferation, apoptosis, and anoikis.
- Investigation of ER stress markers, ATF6 degradation, and RNF139 regulation via ubiquitination and interaction assays.
- In vivo tumor growth assessment in a xenograft mouse model.
- Clinical evaluation of NR4A3 diagnostic performance using serum ELISA and ultrasound in 100 patients.
Main Results:
- NR4A3 overexpression suppressed BCa cell proliferation, colony formation, and promoted apoptosis and anoikis.
- NR4A3 inhibited ER stress by enhancing ATF6 ubiquitination and degradation through the KLF2/4-RNF139 pathway.
- RNF139 directly interacted with ATF6, mediating its ubiquitination.
- NR4A3 overexpression inhibited tumor growth in vivo.
- Combined ultrasound and serum NR4A3 levels achieved high diagnostic accuracy for BCa (AUC = 0.986).
Conclusions:
- NR4A3 acts as a tumor suppressor in BCa by regulating the KLF2/4-RNF139-ATF6 axis.
- NR4A3 plays a critical role in modulating ER stress and anoikis sensitivity in bladder cancer.
- NR4A3, in conjunction with ultrasound, offers a promising diagnostic approach for bladder cancer.
