Disruption of PABPN1 phase separation by SNRPD2 drives colorectal cancer cell proliferation and migration through promoting alternative polyadenylation of CTNNBIP1.

Generally shortened 3' UTR due to alternative polyadenylation (APA) is widely observed in cancer, but its regulation mechanisms for cancer are not well characterized. Here, with profiling of APA in colorectal cancer tissues and poly(A) signal editing, we firstly identified that the shortened 3' UTR of CTNNIBP1 in colorectal cancer promotes cell proliferation and migration. We found that liquid-liquid phase separation (LLPS) of PABPN1 is reduced albeit with higher expression in cancer, and the reduction of LLPS leads to the shortened 3' UTR of CTNNBIP1 and promotes cell proliferation and migration. Notably, the splicing factor SNRPD2 upregulated in colorectal cancer, can interact with glutamic-proline (EP) domain of PABPN1, and then disrupt LLPS of PABPN1, which attenuates the repression effect of PABPN1 on the proximal poly(A) sites. Our results firstly reveal a new regulation mechanism of APA by disruption of LLPS of PABPN1, suggesting that regulation of APA by interfering LLPS of 3' end processing factor may have the potential as a new way for the treatment of cancer.

Paeoniflorin inhibits colorectal cancer cell stemness through the miR-3194-5p/catenin beta-interacting protein 1 axis.

Paeoniflorin (PF) is a natural plant ingredient with remarkable antitumor effects. Herein, we investigated the biological effects and mechanism of PF in colorectal cancer (CRC) cell stemness. The messenger RNA (mRNA) and protein expressions were assessed using quantitative real-time polymerase chain reaction and western blot. The viability, proliferation, and migration and invasion of CRC cells were evaluated using cell counting kit-8, clone-formation, and transwell migration and invasion assays, respectively. The sphere-formation capacity was determined using the sphere-formation assay. A dual-luciferase reporter gene assay was employed to analyze the interaction between miR-3194-5p and catenin beta-interacting protein 1 (CTNNBIP1). The viability, migration, invasion, epithelial-mesenchymal transition, and stemness of CRC cells were repressed by PF. MiR-3194-5p was upregulated in CRC tissues and cells. MiR-3194-5p knockdown suppressed CRC cell stemness, while miR-3194-5p overexpression had the opposite effect. In addition, the inhibition of CRC cell stemness caused by PF was eliminated by miR-3194-5p overexpression. CTNNBIP1 functioned as the target of miR-3194-5p, whose knockdown abrogated the repression of CRC cell stemness and Wnt/ß-catenin signaling activation by PF.PF regulated the miR-3194-5p/CTNNBIP1/Wnt/ß-catenin axis to repress CRC cell stemness.

LINC00355 Mediates CTNNBIP1 Promoter Methylation and Promotes Endoplasmic Reticulum Stress-Induced Podocyte Injury in Diabetic Nephropathy.

Aims: Endoplasmic reticulum stress (ER stress) plays an important role in podocyte injury in diabetic nephropathy. Wnt/ß-catenin signaling modulates ER stress, yet the epigenetic regulation of ß-catenin in ER stress and podocyte injury remains largely unknown. Herein, we tested the hypothesis that LINC00355 recruits EZH1 to the promoter region of CTNNBIP1 and trimethylates H3K4 to regulate ER-stress induced podocyte injury in DN. Results: LINC00355 is upregulated in podocytes and correlates with renal function decline in DN patients. LINC00355 localizes in the nucleus and exerts biological functions by directly binding EZH1, which epigenetically targets CTNNBIP1 through repressive trimethylation of H3K4 and activates Wnt/ß-catenin signaling and ER stress. Further, we provide mechanistic evidences that LINC00355 recruits EZH1 to the promoter region of CTNNBIP1 and regulates ER-stress induced podocyte injury in DN. Innovation and Conclusion: Our data reveal a major role of LINC00355/EZH1/CTNNBIP1 network in triggering podocyte injury, providing new evidences for understanding the role of ER stress in DN. Antioxid. Redox Signal. 39, 225-240.

RNA-binding motif protein 10 represses tumor progression through the Wnt/ß- catenin pathway in lung adenocarcinoma.

RNA-binding motif protein 10 (RBM10), one of the members of the RNA-binding protein (RBP) family, has a tumor suppressor role in multiple cancers. However, the functional role of RBM10 in lung adenocarcinoma (LUAD) and the underlying molecular mechanism remains unclear. In this study, we observed that RBM10 is significantly downregulated in LUAD tissues compared with normal tissues. Low RBM10 expression is significantly associated with poor outcome of LUAD patients. In vitro and in vivo experiments show that RBM10 inhibits cell proliferation, metastasis and EMT progression in LUAD. Mechanistically, we demonstrate that RBM10 interacts with ß-catenin interacting protein 1 (CTNNBIP1) and positively regulates its expression, disrupting the binding of ß-catenin to the transcription factor TCF/LEF, thereby inactivating the Wnt/ß-catenin pathway. In conclusion, this is the first study reporting the role of RBM10 in suppressing LUAD progression at least via partly inactivating the Wnt/ß-catenin pathway, which provides new insights into the tumorigenesis and metastasis of LUAD. Thus, RBM10 may be a promising new therapeutic target or clinical biomarker for LUAD therapy in the future.

The CTNNBIP1-CLSTN1 fusion transcript regulates human neocortical development.

Fusion transcripts or RNAs have been found in both disordered and healthy human tissues and cells; however, their physiological functions in the brain development remain unknown. In the analysis of deposited RNA-sequence libraries covering early to middle embryonic stages, we identify 1,055 fusion transcripts present in the developing neocortex. Interestingly, 98 fusion transcripts exhibit distinct expression patterns in various neural progenitors (NPs) or neurons. We focus on CTNNBIP1-CLSTN1 (CTCL), which is enriched in outer radial glial cells that contribute to cortex expansion during human evolution. Intriguingly, downregulation of CTCL in cultured human cerebral organoids causes marked reduction in NPs and precocious neuronal differentiation, leading to impairment of organoid growth. Furthermore, the expression of CTCL fine-tunes Wnt/ß-catenin signaling that controls cortex patterning. Together, this work provides evidence indicating important roles of fusion transcript in human brain development and evolution.

Functional genetic variants of CTNNBIP1 predict platinum treatment response of Chinese epithelial ovarian cancer patients.

Chemotherapy resistance remains a blockade for successful treatment and longer overall survival of patients with epithelial ovarian cancer (EOC). CTNNBIP1 is an inhibitor of ß-catenin that is a chemotherapeutic target for EOC treatment. In the present study, we investigated associations between single nucleotide polymorphisms (SNPs) of CTNNBIP1 and platinum treatment response of Han Chinese EOC patients and subsequently performed functional prediction and validation of the resultant SNPs. We found that CTNNBIP1 rs935072 AT/TT variant genotypes were associated with platinum treatment response in the multivariate logistic regression analysis of EOC patients. Specifically, the CTNNBIP1 rs935072 AT/TT genotypes were associated with a decreased risk of developing chemoresistance ([adjusted odds ratio (OR)] = 0.89, 95% confidence interval (CI) = 0.82-0.97 and P=0.010), compared with the AA genotype. Further experiments showed that the underlying mechanism for the CTNNBIP1 rs935072 A>T change in chemotherapy treatment response resulted from a lower binding affinity of miR-27a-3p, thereby leading to up-regulation of the CTNNBIP1 expression. We further found that overexpression of CTNNBIP1 sensitized ovarian cancer cells to platinum treatment. Thus, the present study provides evidence that functional variants of CTNNBIP1 may regulate the expression of CTNNBIP1, a possible mechanism affecting platinum treatment response of EOC patients.

The Alteration of CTNNBIP1 in Lung Cancer.

ß-catenin is a major component of the Wnt/ß-catenin signaling pathway, and is known to play a role in lung tumorigenesis. ß-catenin-interacting protein 1 (CTNNBIP1) is a known repressor of ß-catenin transactivation. However, little is known about the role of CTNNBIP1 in lung cancer. The aim of this study was to carry out a molecular analysis of CTNNBIP1 and its effect on ß-catenin signaling, using samples from lung cancer patients and various lung cancer cell lines. Our results indicate a significant inverse correlation between the CTNNBIP1 mRNA expression levels and the CTNNBIP1 promoter hypermethylation, which suggests that the promoter hypermethylation is responsible for the low levels of CTNNBIP1 present in many lung cancer patient samples. The ectopic expression of CTNNBIP1 is able to reduce the ß-catenin transactivation; this then brings about a decrease in the expression of ß-catenin-targeted genes, such as matrix metalloproteinase 7 (MMP7). Conversely, CTNNBIP1 knockdown is able to increase ß-catenin transactivation and the expression of MMP7. In agreement with these findings, a low level of CTNNBIP1 was found to be correlated with a high level of MMP7 when a publicly available microarray dataset for lung cancer was analyzed. Also, in agreement with the above, the ectopic expression of CTNNBIP1 inhibits the migration of lung cancer cells, whereas the CTNNBIP1 knockdown increases cancer cell migration. Our findings suggest that CTNNBIP1 is a suppressor of cancer migration, thus making it a potential prognostic predictor for lung cancer.

CTNNBIP1 downregulation is associated with tumor grade and viral infections in gastric adenocarcinoma.

Gastric cancer is a life-threatening disease; resulting from interaction among genetic, epigenetic, and environmental factors. Aberrant dysregulation and methylation changes in Wnt/ß-catenin signaling downstream elements are a prevalent phenomenon encountered in gastric tumorigenesis. Also, viral infections play a role in gastric cancer development. CTNNBIP1 (ß-catenin interacting protein 1) gene is an antagonist of Wnt signaling which binds to the ß-catenin molecules. The CTNNBIP1 function as tumor suppressor gene or oncogene in different types of cancer is controversial. Moreover, its function and regulatory mechanisms in gastric cancer progression is unknown. In the present study, we examined CTNNBIP1 gene expression, the methylation status of the regulatory region of the gene, and their association with Epstein-Barr virus (EBV), and cytomegalovirus (CMV) and Helicobacter pylori infections in human gastric adenocarcinoma tissues in comparison with their adjacent nontumoral tissues. Our data revealed a significant downregulation of CTNNBIP1 in gastric tumors. Female patients showed lower level of CTNNBIP1 than males (p < 0.05). Also, decreased expression of CTNNBIP1 was markedly associated with well-differentiated tumor grades (p < 0.05). No methylation change was observed between tumoral and nontumoral tissues. Additionally, CTNNBIP1 down regulation was significantly associated with CMV infection (p < 0.05). In the absence of EBV infection, lower expression of CTNNBIP1 was observed. There was no association between H. pylori infection and CTNNBIP1 expression. Our findings revealed the tumor suppressor role for CTNNBIP1 in gastric adenocarcinoma. Interestingly, EBV and CMV infections modulate CTNNBIP1 expression.

CircRNA circRNA_102171 promotes papillary thyroid cancer progression through modulating CTNNBIP1-dependent activation of ß-catenin pathway.

BACKGROUND: As a type of recently discovered noncoding RNA, circular RNAs (circRNAs) exert pivot biological functions in diverse cancers. However, the role of circRNA_102171 in papillary thyroid cancer (PTC) has not been investigated. Our study was focused on the functional investigation toward circRNA_102171 in PTC progression. And we also aimed to reveal its potential molecular mechanism. METHODS: The expression pattern of circRNA_102171 was determined using quantitative polymerase chain reaction (qPCR) in PTC samples and cell lines. Cell proliferation was examined utilizing CCK8, colony formation and EdU incorporation assays. Apoptosis was analyzed by Annexin V/PI staining and FACS detection. Cell migration and invasion was measured using Transwell assay. Tumor growth in vivo was determined through a xenograft assay. RNA-pulldown, RNA-IP (RIP) and RNA-EMSA were used to analyze the interaction between circRNA_102171 and CTNNBIP1. RESULTS: CircRNA_102171 expression was upregulated in tumor tissues and cell lines. CircRNA_102171 silencing suppressed PTC cell proliferation, migration and invasion while promoting apoptosis. CircRNA_102171 knockdown inhibited PTC growth in vivo. CircRNA_102171 interacted with CTNNBIP1 to block its interaction with the ß-catenin/TCF3/TCF4/LEF1 complex, leading to activation of Wnt/ß-catenin pathway. CONCLUSIONS: CircRNA_102171 overexpression promotes PTC progression through activating Wnt/ß-catenin pathway in a CTNNBIP1-dependent way.

Linc00210 drives Wnt/ß-catenin signaling activation and liver tumor progression through CTNNBIP1-dependent manner.

BACKGROUND: Liver tumor initiating cells (TICs) have self-renewal and differentiation properties, accounting for tumor initiation, metastasis and drug resistance. Long noncoding RNAs are involved in many physiological and pathological processes, including tumorigenesis. DNA copy number alterations (CNA) participate in tumor formation and progression, while the CNA of lncRNAs and their roles are largely unknown. METHODS: LncRNA CNA was determined by microarray analyses, realtime PCR and DNA FISH. Liver TICs were enriched by surface marker CD133 and oncosphere formation. TIC self-renewal was analyzed by oncosphere formation, tumor initiation and propagation. CRISPRi and ASO were used for lncRNA loss of function. RNA pulldown, western blot and double FISH were used to identify the interaction between lncRNA and CTNNBIP1. RESULTS: Using transcriptome microarray analysis, we identified a frequently amplified long noncoding RNA in liver cancer termed linc00210, which was highly expressed in liver cancer and liver TICs. Linc00210 copy number gain is associated with its high expression in liver cancer and liver TICs. Linc00210 promoted self-renewal and tumor initiating capacity of liver TICs through Wnt/ß-catenin signaling. Linc00210 interacted with CTNNBIP1 and blocked its inhibitory role in Wnt/ß-catenin activation. Linc00210 silencing cells showed enhanced interaction of ß-catenin and CTNNBIP1, and impaired interaction of ß-catenin and TCF/LEF components. We also confirmed linc00210 copy number gain using primary hepatocellular carcinoma (HCC) samples, and found the correlation between linc00210 CNA and Wnt/ß-catenin activation. Of interest, linc00210, CTNNBIP1 and Wnt/ß-catenin signaling targeting can efficiently inhibit tumor growth and progression, and liver TIC propagation. CONCLUSION: With copy-number gain in liver TICs, linc00210 is highly expressed along with liver tumorigenesis. Linc00210 drives the self-renewal and propagation of liver TICs through activating Wnt/ß-catenin signaling. Linc00210 interacts with CTNNBIP1 and blocks the combination between CTNNBIP1 and ß-catenin, driving the activation of Wnt/ß-catenin signaling. Linc00210-CTNNBIP1-Wnt/ß-catenin axis can be targeted for liver TIC elimination.

Frequent inactivation of MCC/CTNNBIP1 and overexpression of phospho-beta-catenin(Y654) are associated with breast carcinoma: Clinical and prognostic significance.

Transcriptional activation of ß-catenin is a hallmark of Wnt/ß-catenin pathway activation. The MCC (Mutated in colorectal cancers) and CTNNBIP1 (catenin, beta interacting protein 1) are two candidate genes which inhibit the transcriptional activity of nuclear ß-catenin. The importance of MCC and CTNNBIP1 in breast cancer (BC) development has not yet been studied in detail. For this reason, in present study, the alterations (deletion/methylation/mutation/expression) of MCC and CTNNBIP1 were analyzed in BC of Indian patients (N=120) followed by expression/mutation analysis of ß-catenin. Then transcriptional activity of ß-catenin was checked by expression analysis of its target genes (EGFR, C-MYC and CCND1) in the same set of samples. Frequent methylation (44-45%) than deletion (20-32%) with overall alterations of 52-55% was observed in MCC/CTNNBIP1 in the BC samples. The alterations of MCC/CTNNBIP1 showed significant correlation with increased nuclear ß-catenin/p-ß-catenin(Y654) expression. Also, a significant correlation was seen between nuclear ß-catenin expression and overexpression of its target genes like EGFR, MYC and CCND1 in the BC samples (P<0.0001). An upregulation of MCC and CTNNBIP1 expression by 5-Aza-2'-deoxycytidine treatment of MCF7 and MDA-MB-231 cell lines lead to downregulation of ß-catenin and its target genes. The expression of nuclear p-ß-catenin(Y654), EGFR, MYC and CCND1 were significantly high in TNBC (Triple negative BC) and Her2+ compared to Luminal A/B+ subtypes. The TNBC patients in stage III/IV having reduced expression of MCC in the tumors showed poor prognosis. Thus, our data suggests that inactivation of MCC/CTNNBIP1 could be an important event in activation of ß-catenin mediated transcription of target genes in BC.

MiR-215, an activator of the CTNNBIP1/ß-catenin pathway, is a marker of poor prognosis in human glioma.

MicroRNA-215 (miR-215) promotes tumor growth in various human malignancies. However, its role has not yet been determined in human glioma. Here, we found that levels of miR-215 were higher in glioma tissues than in corresponding non-neoplastic brain tissue. High miR-215 expression was correlated with higher World Health Organization (WHO) grades and shorter overall survival. Multivariate and univariate analysis indicated that miR-215 expression was an independent prognostic factor. We also found that TGF-beta1, phosphorylated beta-catenin, alpha-SMA, and fibronectin were increased in glioma tissues. Additionally, CTNNBIP1, a direct target of miR-215, was decreased in glioma compared to adjacent normal tissue. These data indicate that miR-215 activates Wnt/ß-catenin signaling by increasing ß-catenin phosphorylation, α-SMA expression, and fibronectin expression. It promotes TGF-ß1-induced oncogenesis by suppressing CTNNBIP1 in glioma. In summary, miR-215 is overexpressed in human glioma, is involved in TGF-ß1-induced oncogenesis, and can be used as a marker of poor prognosis in glioma patients.

miR-603 promotes glioma cell growth via Wnt/ß-catenin pathway by inhibiting WIF1 and CTNNBIP1.

Gliomas are the most common and deadly type of brain tumor. In spite of progressive treatments, patient prognosis has not improved significantly. MicroRNAs are considered promising candidates for glioma therapy. MiR-603 was found overexpressed in both glioma tissues and cell lines. MiR-603 promoted cell proliferation, cell cycle progression and neurosphere formation. Conversely, inhibition of miR-603 remarkably reduced these effects. We confirmed that WIF1 and CTNNBIP1 are bona fide targets of miR-603. The negative correlation between miR-603 and these molecules' expression was shown by Pearson correlation in 50 primary glioma tissue samples. Furthermore, overexpression of miR-603 promoted nuclear ß-catenin levels and TOPflash luciferase activity, indicating that miR-603 activates the Wnt/ß-catenin signaling pathway. Our in vivo results confirmed the positive role of miR-603 in glioma development. We demonstrate that miR-603 regulates glioma development via its WIF1 and CTNNBIP1 targets, which suggests that miR-603 may be a promising candidate for therapeutic applications in glioma treatment.