SPOP downregulation promotes bladder cancer progression based on cancer cell-macrophage crosstalk via STAT3/CCL2/IL-6 axis and is regulated by VEZF1

  • Theranostics. 2024 Oct 7;14(17):6543-6559. doi: 10.7150/thno.101575.
Meiqian Li  1  2 ,  Yangyan Cui  2 ,  Qi Qi  3 ,  Jiakuan Liu  1 ,  Jiaxuan Li  4 ,  Guifang Huang  5 ,  Jiale Yang  5  6 ,  Jingya Sun  5 ,  Zhihui Ma  5 ,  Shengjie Liang  1 ,  Dianzheng Zhang  7 ,  Jun Jiang  8 ,  Rujian Zhu  1 ,  Qiuli Liu  8 ,  Ruimin Huang  5  6 ,  Jun Yan  1
Affiliations
  • 1. Department of Urology, Shanghai Pudong Hospital, Fudan University Pudong Medical Center; Laboratory Animal Center, Fudan University, Shanghai 200032, China.
  • 2. MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing 210061, China.
  • 3. Laboratory Animal Center, Fudan University, Shanghai 200032, China.
  • 4. Shanghai Institute of Infectious Disease and Biosecurity, School of Public Health, Fudan University, Shanghai 200032, China.
  • 5. Center for Drug Safety Evaluation and Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
  • 6. University of Chinese Academy of Sciences, Beijing 100049, China.
  • 7. Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA 19131, USA.
  • 8. Department of Urology, Daping Hospital, Army Medical University, Chongqing 400042, China.
PMID: 39479456 DOI: 10.7150/thno.101575
Abstract

Background: Cancer cells are intimately intertwined with tumor microenvironment (TME), fostering a symbiotic relationship propelling Cancer progression. However, the interaction between Cancer cells and tumor-associated macrophages (TAMs) in urothelial bladder Cancer (UBC) remains poorly understood. Methods: UBC cell lines (5637, T24 and SW780), along with a monocytic cell line (U937) capable of differentiating into macrophage, were used in a co-culture system for cell proliferation and stemness by MTT, sphere formation assays. VEZF1/SPOP/STAT3/CCL2/ IL-6 axis was determined by luciferase reporter, ChIP, RNA-seq, co-IP, in vitro ubiquitination, RT-qPCR array and ELISA analyses. Results: We observed the frequent downregulation of SPOP, an E3 ubiquitin Ligase, was positively associated with tumor progression and TAM infiltration in UBC patients and T24 xenografts. Cancer cell-TAM crosstalk promoting tumor aggressiveness was demonstrated dependent on SPOP deficiency: 1) In UBC cells, STAT3 was identified as a novel substrate of SPOP, and SPOP deficiency increased STAT3 protein stability, elevated chemokine CCL2 secretion, which induced chemotaxis and M2 polarization of macrophage; 2) In co-cultured macrophages, IL-6 secretion enhanced UBC cell proliferation and stemness. Additionally, transcription factor VEZF1 could directly activate SPOP transcription, and its overexpression suppressed the above effects in UBC cells. Conclusions: A pivotal role of SPOP in maintaining UBC stemness and remodeling immunosuppressive TME was revealed. Both the intrinsic signaling (dysregulated VEZF1/SPOP/STAT3 axis) and the extrinsic cues from TME (CCL2-IL-6 axis based on macrophages) promoted UBC progression. Targeting this crosstalk may offer a promising therapeutic strategy for UBC patients with SPOP deficiency.

Keywords
SPOP; STAT3/CCL2/IL-6 axis; VEZF1; bladder cancer; tumor-associated macrophage.
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