Int J Biol Sci 2022; 18(13):5207-5220. doi:10.7150/ijbs.69373 This issue

Research Paper

Nitroxoline suppresses metastasis in bladder cancer via EGR1/circNDRG1/miR-520h/smad7/EMT signaling pathway

Liangliang Ren1#, Minxiao Jiang1#, Dingwei Xue1#, Huan Wang1, Zeyi Lu1, Lifeng Ding1, Haiyun Xie1, Ruyue Wang1, Wenqin Luo1, Li Xu1, Mingchao Wang1, Shicheng Yu1, Sheng Cheng1, Liqun Xia1, Haifeng Yu1, Peng Huang2,3✉, Naijin Xu1✉, Gonghui Li1✉

1. Department of Urology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.
2. Department of Urology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
3. Department of Urology, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
#These authors have contributed equally to this work and share first authorship.

This is an open access article distributed under the terms of the Creative Commons Attribution License ( See for full terms and conditions.
Ren L, Jiang M, Xue D, Wang H, Lu Z, Ding L, Xie H, Wang R, Luo W, Xu L, Wang M, Yu S, Cheng S, Xia L, Yu H, Huang P, Xu N, Li G. Nitroxoline suppresses metastasis in bladder cancer via EGR1/circNDRG1/miR-520h/smad7/EMT signaling pathway. Int J Biol Sci 2022; 18(13):5207-5220. doi:10.7150/ijbs.69373. Available from

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Graphic abstract

Bladder cancer is one of the most common and deadly cancer worldwide. Current chemotherapy has shown limited efficacy in improving outcomes for patients. Nitroxoline, an old and widely used oral antibiotic, which was known to treat for urinary tract infection for decades. Recent studies suggested that nitroxoline suppressed the tumor progression and metastasis, especially in bladder cancer. However, the underlying mechanism for anti-tumor activity of nitroxoline remains unclear.

Methods: CircRNA microarray was used to explore the nitroxoline-mediated circRNA expression profile of bladder cancer lines. Transwell and wound-healing assay were applied to evaluate the capacity of metastasis. ChIP assay was chosen to prove the binding of promotor and transcription factor. RNA-pulldown assay was performed to explore the sponge of circRNA and microRNA.

Results: We first identified the circNDRG1 (has_circ_0085656) as a novel candidate circRNA. Transwell and wound-healing assay demonstrated that circNDRG1 inhibited the metastasis of bladder cancer. ChIP assay showed that circNDRG1 was regulated by the transcription factor EGR1 by binding the promotor of host gene NDRG1. RNA-pulldown assay proved that circNDRG1 sponged miR-520h leading to the overexpression of smad7, which was a negative regulatory protein of EMT.

Conclusions: Our research revealed that nitroxoline may suppress metastasis in bladder cancer via EGR1/circNDRG1/miR-520h/smad7/EMT signaling pathway.

Keywords: Bladder cancer, nitroxoline, metastasis circNDRG1, microRNA