UBE2C-induced crosstalk between mono- and polyubiquitination of SNAT2 promotes lymphatic metastasis in bladder cancer
Wenjie Li, … , Tianhang Lan, Wang He
Wenjie Li, … , Tianhang Lan, Wang He
Published July 1, 2024
Citation Information: J Clin Invest. 2024;134(13):e179122. https://doi.org/10.1172/JCI179122.
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Research Article Cell biology Oncology

UBE2C-induced crosstalk between mono- and polyubiquitination of SNAT2 promotes lymphatic metastasis in bladder cancer

Abstract

Ubiquitination plays an essential role in protein stability, subcellular localization, and interactions. Crosstalk between different types of ubiquitination results in distinct biological outcomes for proteins. However, the role of ubiquitination-related crosstalk in lymph node (LN) metastasis and the key regulatory factors controlling this process have not been determined. Using high-throughput sequencing, we found that ubiquitin-conjugating enzyme E2 C (UBE2C) was overexpressed in bladder cancer (BCa) and was strongly associated with an unfavorable prognosis. Overexpression of UBE2C increased BCa lymphangiogenesis and promoted LN metastasis both in vitro and in vivo. Mechanistically, UBE2C mediated sodium-coupled neutral amino acid transporter 2 (SNAT2) monoubiquitination at lysine 59 to inhibit K63-linked polyubiquitination at lysine 33 of SNAT2. Crosstalk between monoubiquitination and K63-linked polyubiquitination increased SNAT2 membrane protein levels by suppressing epsin 1–mediated (EPN1-mediated) endocytosis. SNAT2 facilitated glutamine uptake and metabolism to promote VEGFC secretion, ultimately leading to lymphangiogenesis and LN metastasis in patients with BCa. Importantly, inhibition of UBE2C significantly attenuated BCa lymphangiogenesis in a patient-derived xenograft model. Our results reveal the mechanism by which UBE2C mediates crosstalk between the monoubiquitination and K63-linked polyubiquitination of SNAT2 to promote BCa metastasis and identify UBE2C as a promising target for treating LN-metastatic BCa.

Authors

Wenjie Li, Changhao Chen, Hanhao Zheng, Yan Lin, Mingjie An, Daiyin Liu, Yonghai Zhang, Mingchao Gao, Tianhang Lan, Wang He

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Figure 2

UBE2C promotes lymphangiogenesis and LN metastasis in BCa.

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UBE2C promotes lymphangiogenesis and LN metastasis in BCa. (A–D) IB anal...
(A–D) IB analysis of UBE2C expression following UBE2C overexpression or knockdown in BCa cells. (E–G) Representative images and quantification of tube formation and migration of HLECs after coculturing with UBE2C-knockdown or UBE2C-overexpressing UM-UC-3 cells. Scale bars: 100 μm. (H and I) Diagrammatic representation of the popliteal LN metastasis model using nude mice. (J and K) Representative images and quantification of bioluminescence in popliteal metastatic LNs (n = 12). Red arrows indicate footpad tumors and metastatic popliteal LNs. (L) Representative images and bioluminescence results for popliteal LNs from 2 groups of mice (n = 12). (M) Representative IHC images of anti–mCherry antibody–treated popliteal LNs from mice (n = 12). Red scale bar: 500 μm; black scale bars: 50 μm. (N and O) Representative IHC images and quantification of UBE2C expression and LYVE1-indicated MLD in the peritumoral (N) and intratumoral (O) regions of footpad tumor tissues. Scale bars: 50 μm. Significant differences were identified through 1-way ANOVA followed by Dunnett’s test (E) and 2-tailed Student’s t test (G, K, N, and O). Quantitative results are presented as the mean ± SEM of 3 separate experiments.