Carbonic anhydrase IVinhibits colon cancer development by inhibiting the Wnt signalling pathway through targeting the WTAP–WT1–TBL1 axis

Abstract

ObjectiveWe 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.DesignThe 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.ResultsCA4 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.ConclusionsCA4 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.

Carbonic anhydrase XII functions in health and disease

“…Progressive renal injuries have also been observed in transgenic mice expressing folding mutants of CAIV (18). Recently, it has been reported that mouse CAIV is also a tumor suppresser protein as well (19), and it may have some role in wound healing (Altonen M., Barker H., Pan P., unpublished observations, 2016).…”

Wilms’ tumor 1-associating protein promotes renal cell carcinoma proliferation by regulating CDK2 mRNA stability

“…Moreover, its overexpression was correlated with a poor prognosis in acute myeloid leukemia [ 17 ], malignant glioma [ 18 ], and pancreatic ductal adenocarcinoma [ 19 ]. In the investigation for the oncogenic mechanism of WTAP, it was found that WTAP could act as an oncogenic protein by regulating the expressions of matrix metalloproteinase (MMP) 7, MMP28, cathepsin H and Muc1 [ 15 ], controlling epidermal growth factor signaling [ 16 ], regulating mTOR pathway and targeting the WT1-TBL1 axis [ 20 ]. However, unlike WT1, the role of WTAP in RCC was still unknown.…”

Identification of WT1 as determinant of heptatocellular carcinoma and its inhibition by Chinese herbal medicine Salvia chinensis Benth and its active ingredient protocatechualdehyde

“…The transcriptional regulation of WT1 on β-catenin may thus be indirect and is dependent to the presence of other determinant factors. This may also explain the observations that in some circumstances, WT1 may serve as a repressor of β-catenin [ 38 – 41 ]. The exact mechanism of WT1-regulated Wnt/β-catenin activity needs further investigation.…”