YAP1-CPNE3 positive feedback pathway promotes gastric cancer cell progression

Hippo-Yes-associated protein 1 (YAP1) plays an important role in gastric cancer (GC) progression; however, its regulatory network remains unclear. In this study, we identified Copine III (CPNE3) was identified as a novel direct target gene regulated by the YAP1/TEADs transcription factor complex. The downregulation of CPNE3 inhibited proliferation and invasion, and increased the chemosensitivity of GC cells, whereas the overexpression of CPNE3 had the opposite biological effects. Mechanistically, CPNE3 binds to the YAP1 protein in the cytoplasm, inhibiting YAP1 ubiquitination and degradation mediated by the E3 ubiquitination ligase β-transducin repeat-containing protein (β-TRCP). Thereby activating the transcription of YAP1 downstream target genes, which creates a positive feedback cycle to facilitate GC progression. Immunohistochemical analysis demonstrated significant upregulation of CPNE3 in GC tissues. Survival and Cox regression analyses indicated that high CPNE3 expression was an independent prognostic marker for GC. This study elucidated the pivotal involvement of an aberrantly activated CPNE3/YAP1 positive feedback loop in the malignant progression of GC, thereby uncovering novel prognostic factors and therapeutic targets in GC.

[High expression of CPNE3 correlates with poor long-term prognosis of gastric cancer by inhibiting cell apoptosis via activating PI3K/AKT signaling]

OBJECTIVE

To explore the correlation of CPNE3 expression with long-term prognosis of patients with gastric cancer (GC) and the possible mechanism.

METHODS

We retrospectively collected the data of 104 GC patients undergoing radical surgery in our hospital from February, 2013 to October, 2017. TCGA database and immunohistochemistry were used to analyze CPNE3 expression level in GC tissues and its effects on tumor progression and long-term prognosis of the patients. GO analysis was performed to predict the biological role of CPNE3 in GC. We also conducted cell experiments with MGC803 cells and observed the effects of CPNE3 knockdown, CPNE3 overexpression and LY294002 (a PI3K/AKT inhibitor) treatment on cell apoptosis and cellular expressions of apoptotic proteins using flow cytometry and Western blotting.

RESULTS

TCGA analysis and immunohistochemistry both showed high expressions of CPNE3 in GC (P < 0.05). The patients with high CPNE3 expressions had a reduced 5-year survival (P < 0.01), and a high CPNE3 expression, CEA level≥5 μg/L, CA19-9 level ≥37 kU/L, T3-T4 stage, and N2-N3 stage were all independent risk factors for a lowered 5-year survival rate after surgery. The sensitivity and specificity of CPNE3 for predicting 5-year mortality was 79.59% and 74.55%, respectively (P < 0.05). GO analysis predicted that CPNE3 negatively regulated GC cell apoptosis. In MGC803 cells, CPNE3 knockdown significantly increased cell apoptosis, enhanced Bax and Cleaved Caspase-3 expressions and decreased Bcl-2 expression, while CPNE3 overexpression produced the opposite results (P < 0.05). The cellular expressions of p-PI3K and p-AKT were significantly decreased following CPNE3 knockdown and increased following CPNE3 overexpression (P < 0.05). Treatment with LY294002 obviously attenuated the inhibitory effect of CPNE3 overexpression on apoptosis of MGC803 cells (P < 0.05).

CONCLUSION

CPNE3 is highly expressed in GC tissues and affects the long-term prognosis of the patients possibly by inhibiting GC cell apoptosis through activation of PI3K/AKT signaling.

CPNE3 regulates the cell proliferation and apoptosis in human Glioblastoma via the activation of PI3K/AKT signaling pathway

Background: Even with decades of intensive study, the signaling regulative network of the progression of Glioblastoma (GBM) remains unclear, a deeper understanding of the molecular crosstalk with pathways in GBM is needed to identify new potential targets for treatment. Copine-3 (CPNE3) was a member of a Ga2+ -dependent phospholipid-binding protein and was reported to play a role in multiple cancers.

Methods: To investigate the expression of CPNE3 in GBM, we applied bioinformatic analysis and clinical samples validation. Then the functional validation of carried out in commercially available glioma cell lines and nude mice model. Also, the GSEA analysis was used to identify the relevant pathways. The role of activated pathway was further validated by pharmacology method.

Results: We found that CPNE3 was significantly up-regulated in GBM when compared with adjacent normal tissues, and the overexpression of CPNE3 promoted cell proliferation and inhibiting cell apoptosis in vitro and in vivo. Also, the principal protein markers of PI3K/AKT pathway were found to be phosphorylated by CPNE3 over-expression, and pathway inhibitor, LY294002, alleviated the cell proliferation enhancement induced by CPNE3 over-expression.

Conclusion: Our results showed that the expression of CPNE3 promotes cell proliferation by inhibiting cell apoptosis via activating PI3K/AKT pathway. Thereby enhancing the progression of GBM, which suggest that CPNE3 may play as a tumorigenesis gene may become a promising potential therapeutic target for human GBMs.

Upregulation of CPNE3 suppresses invasion, migration and proliferation of glioblastoma cells through FAK pathway inactivation

Glioblastoma (GBM) is a deadly brain tumor with a bleak prognosis. In recent years, the copine III (CPNE3) protein was discovered to be associated to metastasis across various types of malignancies. Nevertheless, its function has not been well documented in glioma. This study characterizes CPNE3 expression in GBM along with its impact and underlying molecular mechanism with regards to cellular migration, invasion and proliferation. Immunohistochemistry was used to characterizes CPNE3 expression in the glioma tissues. Then, knockdown of CPNE3 expression was used to analyze the role of CPNE3 in GBM cell viability, migration, invasion. Western blot analysis was performed to measure the protein levels of FAK signaling pathway. We found that GBM tissues had higher CPNE3 expressions as compared to those in normal brain tissues. CPNE3 silencing in GBM cells impaired the migratory, invasive and proliferative abilities of GBM cells that can be attributed to inactivation of the FAK signaling pathway. Collectively, these findings highlight the role of CPNE3 as a new biomarker, offering deeper insights into its carcinogenic role in GBM.

CPNE3 promotes migration and invasion in non-small cell lung cancer by interacting with RACK1 via FAK signaling activation

Approximately 90% of patients diagnosed with non-small cell lung cancer (NSCLC) die due to distant metastases. However, the complicated molecular and cellular mechanisms involved in lung cancer metastasis remain poorly understood. Copine III (CPNE3), a member of a Ca²⁺-dependent phospholipid-binding protein family, was identified as a novel metastasis-associated protein in NSCLC in our previous study, however, its function in metastasis remains unclear. Here, we found that CPNE3 was expressed at high levels in NSCLC tissues and advanced TNM stages and was significantly associated with poor prognosis. In addition, CPNE3 interacted with phosphorylated erb-b2 receptor tyrosine kinase 2 (pErbB2) and receptor of activated protein C kinase 1 (RACK1) and activated the focal adhesion (FA) signaling pathway in NSCLC cells. Moreover, knockdown of RACK1 inhibited cell motility in the CPNE3-overexpressed NSCLC cells. These findings offer mechanistic insights into the oncogenic roles of CPNE3 and the pivotal effects of CPNE3 as a biomarker and therapeutic target for NSCLC metastasis.

Silencing the expression of copine-III enhances the sensitivity of hepatocellular carcinoma cells to the molecular targeted agent sorafenib

Background

The application of the oral targeted therapeutic agent sorafenib provides new hope for patients suffering from advanced stages of hepatocellular carcinoma (HCC), but the prognosis of such patients remains poor due to the rapid development of the multidrug resistance process in cancer pathogenesis. The present work evaluated whether copine-III, a novel cancer regulator encoded by the CPNE3 gene, would be a potential indicator of sorafenib resistance in HCC treatment.

Materials and methods

The endogenous expression of copine-III in clinical specimens was examined by quantitative polymerase chain reaction. Copine-III siRNA was transfected into HCC cells to downregulate copine-III expression. The effect of copine-III on sorafenib’s antitumor activation was identified by in vitro and in vivo experiments (MTT, Transwell, and flow cytometry as well as a nude mice model).

Results

High levels of copine-III in clinical specimens are related to poor prognosis of advanced HCC patients on sorafenib treatment. Infection of Ad-siCPNE3 significantly decreased the endogenous expression of copine-III and enhanced the susceptibility of MHCC97-H cells to sorafenib: the IC₅₀ value decreased from 1.15±0.11 to 0.25±0.05 μmol/L. Moreover, silencing copine-III enhanced the effect of sorafenib on apoptosis, in vitro invasion/migration, and subcutaneous or intrahepatic growth of MHCC97-H cells in nude mice.

Conclusion

Copine-III is a novel potential indicator of prognosis for patients who received sorafenib for advanced HCC treatment.

High expression of CPNE3 predicts adverse prognosis in acute myeloid leukemia

CPNE3, a member of a Ca²⁺‐dependent phospholipid‐binding protein family, was identified as a ligand of ERBB2 and has a more general role in carcinogenesis. Here, we identified the prognostic significance of CPNE3 expression in acute myeloid leukemia (AML) patients based on two datasets. In the first microarray dataset (n = 272), compared to low CPNE3 expression (CPNE3^low), high CPNE3 expression (CPNE3^high) was associated with adverse overall survival (OS, P < 0.001) and event‐free survival (EFS, P < 0.001). In the second independent group of AML patients (TCGA dataset, n = 179), CPNE3^high was also associated with adverse OS and EFS (OS, P = 0.01; EFS, P = 0.036). Notably, among CPNE3^high patients, those received allogenic hematopoietic cell transplantation (HCT) had longer OS and EFS than those with chemotherapy alone (allogeneic HCT, n = 40 vs chemotherapy, n = 46), but treatment modules played an insignificant role in the survival of CPNE3^low patients (allogeneic HCT, n = 32 vs chemotherapy, n = 54). These results indicated that CPNE3^high is an independent, adverse prognostic factor in AML and might guide treatment decisions towards allogeneic HCT. To understand its inherent mechanisms, we investigated genome‐wide gene/microRNA expression signatures and cell signaling pathways associated with CPNE3 expression. In conclusion, CPNE3^high is an adverse prognostic biomarker for AML. Its effect may be attributed to the distinctive genome‐wide gene/microRNA expression and related cell signaling pathways.