Inhibition of β-Catenin Activity Abolishes LKB1 Loss-Driven Pancreatic Cystadenoma in Mice

RNF43 as a predictor of malignant transformation of pancreatic mucinous cystic neoplasm

Mucinous cystic neoplasm (MCN) of the pancreas rarely progresses to invasive carcinoma, but few studies have analyzed genomic alterations involved in its malignant transformation. The relationships of ring finger protein 43 (RNF43) mutations with cytological atypia, RNF43 protein expression, and Wnt signaling proteins in MCN remain unclear. This study included 106 MCN cases, classified into 89 low-grade dysplasia (LG), 9 high-grade dysplasia (HG), and 8 invasive carcinoma (INV). We analyzed HG/INV and LG lesions of 9 HG/INV cases and LG lesions of 9 LG cases using targeted sequencing and confirmed the protein expression of RNF43 and β-catenin. The frequency of RNF43 mutations was significantly higher in HG/INV cases than in LG cases. Furthermore, HG/INV lesions (56%) and LG lesions (33%) of HG/INV cases possessed RNF43 mutation, whereas no such mutation was detected in any LG cases. The expression of RNF43 was reduced in 71% of HG/INV cases and significantly correlated with histological grade and aberrant expression of β-catenin. In 3 of 5 RNF43-mutated cases, the expression of RNF43 was reduced, but there was no significant correlation between RNF43 mutation and protein expression. MCNs frequently harbored KRAS mutations, at rates of 100% in HG/INV lesions and 50% in LG lesions of HG/INV and LG cases. There was no significant difference in mutation frequency in LG lesions between HG/INV and LG cases. These results suggest that RNF43 mutations may be involved in and predictive of malignant transformation from an early stage of MCN.

Cysteine-Rich Intestinal Protein 1 Served as an Epithelial Ovarian Cancer Marker via Promoting Wnt/β-Catenin-Mediated EMT and Tumour Metastasis

Objective

To explore the expression, functions, and the possible mechanisms of cysteine-rich intestinal protein 1 (CRIP1) in epithelial ovarian cancer.

Methods

Using open microarray datasets from The Cancer Genome Atlas (TCGA), we identified the tumorigenic genes in ovarian cancer. Then, we detected CRIP1 expression in 26 pairs of epithelial ovarian cancer tissue samples by immunohistochemistry (IHC) and performed a correlation analysis between CRIP1 and the clinicopathological features. In addition, epithelial ovarian cancer cell lines A2780 and OVCAR3 were used to examine CRIP1 expression by western blot and qRT-PCR. Various cell function experiments related to tumorigenesis were performed including the CCK8 assay, EdU, Annexin V-FITC/PI apoptosis assay, wound healing, and Transwell assay. In addition, the expression of epithelial-mesenchymal transition (EMT) markers was detected by western blot to illustrate the relationship between CRIP1 and EMT. Furthermore, KEGG pathway enrichment analysis and western blot were conducted to reveal the signaling pathways in which CRIP1 is involved in ovarian cancer pathogenesis.

Results

CRIP1 was identified as an oncogene from the TCGA database. The IHC score demonstrated that the CRIP1 protein was expressed at a higher level in tumours than in tumour-adjacent tissues and was associated with a higher pathological stage, grade, and positive lymphatic metastasis. In cell models, CRIP1 was overexpressed in serous epithelial ovarian cancer. Cell function experiments showed that the knockdown of CRIP1 did not significantly affect cell proliferation or apoptosis but could exert an inhibitory effect on cell migration and invasion, and also induce changes in EMT markers. Furthermore, KEGG pathway enrichment analysis and western blot showed that CRIP1 could induce ovarian cancer cell metastasis through activation of the Wnt/β-catenin pathway.

Conclusion

This study is the first to demonstrate that CRIP1 acts as an oncogene and may promote tumour metastasis by regulating the EMT-related Wnt/β-catenin signaling pathway, suggesting that CRIP1 may be an important biomarker for ovarian cancer metastasis and progression.