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Updated: Apr 10, 2026
In vitro Organoid Culture of Primary Mouse Colon Tumors
Published on: May 17, 2013
Carbonic anhydrase IV inhibits colon cancer development by inhibiting the Wnt signalling pathway through targeting
Jingwan Zhang1, Ho Tsoi1, Xiaoxing Li1
1Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
Objective:
We found that carbonic anhydrase IV (CA4), a member of the carbonic anhydrases, is silenced in colorectal cancer (CRC). We analysed its epigenetic inactivation, biological effects and prognostic significance in CRC.
Design:
The biological functions of CA4 were determined by in vitro and in vivo tumorigenicity assays. The CA4 co-operator was identified by immunoprecipitation and mass spectrometry. CA4 downstream effectors and signalling pathways were elucidated by promoter luciferase assay, electrophoretic mobility shift assay and chromatin immunoprecipitation. The clinical impact of CA4 was assessed in 115 patients with CRC.
Results:
CA4 was silenced in all nine CRC cell lines and 92.6% of CRC tumours. The promoter hypermethylation contributed to the inactivation of CA4, and it was detected in 75.7% of the patients with CRC. After a median follow-up of 49.3 months, multivariate analysis showed that the patients with CA4 hypermethylation had a recurrence of Stage II/III CRC. The re-expression of CA4 inhibited cell proliferation, induced apoptosis and cell cycle arrest in the G1 phase. CA4 inhibited the activity of the Wnt signalling pathway and mediated the degradation of β-catenin. CA4 interacted with Wilms' tumour 1-associating protein (WTAP) and induced WTAP protein degradation through polyubiquitination. Moreover, CA4 promoted the transcriptional activity of Wilms' tumour 1 (WT1), an antagonist of the Wnt pathway, which resulted in the induction of transducin β-like protein 1 (TBL1) and the degradation of β-catenin.
Conclusions:
CA4 is a novel tumour suppressor in CRC through the inhibition of the Wnt signalling pathway by targeting the WTAP-WT1-TBL1 axis. CA4 methylation may serve as an independent biomarker for the recurrence of CRC.
Insights
Carbonic anhydrase IV (CA4) is silenced in colorectal cancer (CRC) due to promoter hypermethylation. Restoring CA4 suppresses tumor growth by inhibiting the Wnt pathway, suggesting CA4 as a potential biomarker for CRC recurrence.
Area of Science:
- Oncology
- Molecular Biology
- Epigenetics
Background:
- Colorectal cancer (CRC) is a major global health concern.
- The role of carbonic anhydrase IV (CA4) in CRC pathogenesis is not well understood.
- Epigenetic silencing of tumor suppressor genes is a common mechanism in cancer development.
Purpose of the Study:
- To investigate the epigenetic inactivation, biological functions, and prognostic significance of carbonic anhydrase IV (CA4) in colorectal cancer (CRC).
- To elucidate the molecular mechanisms underlying CA4's tumor-suppressive activity in CRC.
- To evaluate CA4 methylation as a potential biomarker for CRC recurrence.
Main Methods:
- Analysis of CA4 expression and promoter hypermethylation in CRC cell lines and patient tumors.
- In vitro and in vivo tumorigenicity assays to assess CA4's biological functions.
- Immunoprecipitation, mass spectrometry, and various molecular assays to identify CA4 interactors and downstream signaling pathways.
- Multivariate analysis of clinical data from 115 CRC patients to determine prognostic significance.
Main Results:
- CA4 was found to be silenced in all tested CRC cell lines and a high percentage of CRC tumors, primarily due to promoter hypermethylation.
- CA4 hypermethylation was significantly associated with tumor recurrence in Stage II/III CRC patients.
- Re-expression of CA4 inhibited cell proliferation, induced apoptosis, and arrested the cell cycle.
- CA4 was shown to inhibit the Wnt signaling pathway by targeting the WTAP-WT1-TBL1 axis and promoting β-catenin degradation.
Conclusions:
- CA4 acts as a novel tumor suppressor in CRC by inhibiting the Wnt signaling pathway through the WTAP-WT1-TBL1 axis.
- CA4 promoter hypermethylation serves as an independent biomarker for predicting CRC recurrence.
- Targeting CA4 or its associated pathways may offer therapeutic strategies for CRC.
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