RCC2 and CD24 cooperate to modulate prostate cancer progression through vimentin ubiquitination and β-catenin activation
Xuelian Cui, Yicun Wang, Chao Zhang, Zhichao Liu, Haiyan Yu, Lizhong Wang, Jiangbing Zhou, Runhua Liu
Xuelian Cui, Yicun Wang, Chao Zhang, Zhichao Liu, Haiyan Yu, Lizhong Wang, Jiangbing Zhou, Runhua Liu
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Research Article Cell biology Genetics Oncology

RCC2 and CD24 cooperate to modulate prostate cancer progression through vimentin ubiquitination and β-catenin activation

Abstract

CD24 promotes prostate cancer progression and metastasis by disrupting the ARF-NPM interaction and impairing p53 signaling. However, the mechanisms underlying CD24-driven metastasis remain unclear. This study identifies a novel interaction between CD24 and Regulator of Chromosome Condensation 2 (RCC2), a protein involved in cell proliferation and migration. IHC analysis of prostate adenocarcinoma samples showed frequent coexpression of CD24 (49%) and RCC2 (82%) with a positive correlation between coexpression of CD24 (49%) and RCC2 (82%). Functional assays revealed complex roles: RCC2 KO suppressed proliferation but increased migration and invasion, while CD24 KO reduced both proliferation and migration. Dual KO of CD24 and RCC2 further inhibited proliferation but had varied effects on migration. In mouse xenografts, RCC2 KO increased lung metastasis without significantly affecting primary tumor growth, while CD24 KO reduced both tumor growth and metastasis. Mechanistically, RCC2 controls migration by promoting ubiquitination and degradation of vimentin, affecting cytoskeletal dynamics. In contrast, CD24 targets RCC2 for degradation, thereby regulating β-catenin signaling. Notably, RCC2 KO enhances β-catenin activity by suppressing inhibitors AXIN2 and APC, whereas CD24 KO inhibits this pathway. These findings reveal a regulatory loop where CD24 and RCC2 reciprocally control proliferation and metastasis, positioning the CD24-RCC2 axis as a promising therapeutic target in prostate cancer.

Authors

Xuelian Cui, Yicun Wang, Chao Zhang, Zhichao Liu, Haiyan Yu, Lizhong Wang, Jiangbing Zhou, Runhua Liu

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Figure 4

Interaction between RCC2 and Vimentin and the role of RCC2 in Vimentin degradation in DU145 cells.

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Interaction between RCC2 and Vimentin and the role of RCC2 in Vimentin d...
(A) Identification of Vimentin as a top RCC2-binding partner by mass spectrometry analysis of Flag-RCC2 overexpressed in HEK293T cells, showing 13 matching peptides from Vimentin. (B) Table listing Vimentin peptides identified by mass spectrometry, highlighting the potential interaction sites with RCC2. (C) Immunofluorescence images showing the localization of RCC2 and Vimentin in DU145 cells using specific anti-RCC2 and anti-Vimentin antibodies. Scale bar: 10 μm. (D) Quantitative analysis of RCC2 and vimentin colocalization using ImageJ/Fiji with the JaCoP plugin. Pearson’s correlation coefficient (PCC) indicates the linear relationship between the fluorescence intensities of RCC2 and vimentin. Manders’ overlap coefficient (MOC) values represent the extent of signal overlap: MOC-M1 reflects the fraction of RCC2 signal overlapping with vimentin, while MOC-M2 reflects the fraction of vimentin signal overlapping with RCC2. Data were obtained from 3–4 independent immunofluorescence experiments, each with 3–4 images per condition (6–8 cells per image). Data are presented as mean ± SE. The coefficients were determined using Pearson’s correlation test. (E) Coimmunoprecipitation (co-IP) assays with anti-RCC2 and anti-Vimentin antibodies in DU145 cells confirming the interaction between RCC2 and Vimentin. (F) Immunoblot analysis showing Vimentin expression in RCC2 KO cells, CD24 KO + RCC2 overexpression (OE) cells, and CD24/RCC2 double KO (D-KO) cells. (G) Vimentin expression in scrambled control and RCC2 OE + CD24 KO DU145 cells treated with the proteasome inhibitor MG-132 (10 μM) for 6, 12, and 24 hours. (H) Immunoprecipitation with anti-Vimentin followed by anti-Ubiquitin immunoblotting in MG-132-treated lysates of scrambled control, RCC2 OE + CD24 KO, and RCC2 KO DU145 cells. The experiments were repeated 3 times.