Upregulated RACK1 attenuates gastric cancer cell growth and epithelial-mesenchymal transition via suppressing Wnt/β-catenin signaling

Low expression of RACK1 is associated with metastasis and worse prognosis in cholangiocarcinoma

Background

Cholangiocarcinoma is a poorly prognostic malignant tumor, and the metastatic stage of cancer is not an early stage when diagnosed. Lymph node metastasis is common in the early stage. Ribosomal receptor for activated C-kinase 1 (RACK1) has found involved in the oncogenesis of various tumors and in the epithelial-mesenchymal transition (EMT). Nevertheless, its role in cholangiocarcinoma remains unknown.

Material and methods

The possible correlation between RACK1 and tumor prognosis was analyzed in cholangiocarcinoma patients. The GEO and TCGA databases were used to evaluate the level of RACK1 in cholangiocarcinoma. The RBE and HCCC-9810 cell lines were used to examine the effects of RACK1 in the behavior of tumor cells in vitro.

Results

The Kaplan-Meier analysis indicated that low expression of RACK1 was associated with poor prognosis and RACK1 was negatively related to lymph node metastasis, which were verified in databases TCGA and GEO; downregulation of RACK1 via RNA interference correlated with changes in the expression of EMT biomarkers and promoted the migration of cholangiocarcinoma cell lines.

Conclusion

The protein expression of RACK1 is significantly higher in cholangiocarcinoma tissues than in peritumoral tissues, however, the high RACK1 expression indicates better overall survival and less risk for lymph node metastasis. In vitro, RACK1 may suppress the migratory ability of cholangiocarcinoma cells by inhibiting EMT.

Role of the receptor for activated C kinase 1 during viral infection

Viruses can survive only in living cells, where they depend on the host's enzymatic system for survival and reproduction. Virus-host interactions are complex. On the one hand, hosts express host-restricted factors to protect the host cells from viral infections. On the other hand, viruses recruit certain host factors to facilitate their survival and transmission. The identification of host factors critical to viral infection is essential for comprehending the pathogenesis of contagion and developing novel antiviral therapies that specifically target the host. Receptor for activated C kinase 1 (RACK1), an evolutionarily conserved host factor that exists in various eukaryotic organisms, is a promising target for antiviral therapy. This review primarily summarizes the roles of RACK1 in regulating different viral life stages, particularly entry, replication, translation, and release.

CPNE1 promotes non-small cell lung cancer progression by interacting with RACK1 via the MET signaling pathway

Background

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and the most lethal tumour worldwide. Copine 1 (CPNE1) was identified as a novel oncogene in NSCLC in our previous study. However, its specific function and relative mechanisms remain poorly understood.

Methods

The biological role of CPNE1 and RACK1 in NSCLC was investigated using gene expression knockdown and overexpression, cell proliferation assays, clonogenic assays, and Transwell assays. The expression levels of CPNE1, RACK1 and other proteins were determined by western blot analysis. The relationship between CPNE1 and RACK1 was predicted and investigated by mass spectrometry analysis, immunofluorescence staining, and coimmunoprecipitation. NSCLC cells were treated with a combination of a MET inhibitor and gefitinib in vitro and in vivo.

Results

We found that CPNE1 facilitates tumorigenesis in NSCLC by interacting with RACK1, which further induces activation of MET signaling. CPNE1 overexpression promoted cell proliferation, migration, invasion and MET signaling in NSCLC cells, whereas CPNE1 knockdown produced the opposite effects. In addition, the suppression of the enhancing effect of CPNE1 overexpression on tumorigenesis and MET signaling by knockdown of RACK1 was verified. Moreover, compared to single-agent treatment, dual blockade of MET and EGFR resulted in enhanced reductions in the tumour volume and downstream signaling in vivo.

Conclusions

Our findings show that CPNE1 promotes tumorigenesis by interacting with RACK1 and activating MET signaling. The combination of a MET inhibitor with an EGFR-TKI attenuated tumour growth more significantly than either single-drug treatment. These findings may provide new insights into the biological function of CPNE1 and the development of novel therapeutic strategies for NSCLC.

Anti-tumor activity of resveratrol against gastric cancer: a review of recent advances with an emphasis on molecular pathways

Gastric cancer (GC) is one of the most common cancers with high malignancy. In spite of the great development in diagnostic tools and application of anti-tumor drugs, we have not witnessed a significant increase in the survival time of patients with GC. Multiple studies have revealed that Wnt, Nrf2, MAPK, and PI3K/Akt signaling pathways are involved in GC invasion. Besides, long non-coding RNAs and microRNAs function as upstream mediators in GC malignancy. GC cells have acquired resistance to currently applied anti-tumor drugs. Besides, combination therapy is associated with higher anti-tumor activity. Resveratrol (Res) is a non-flavonoid polyphenol with high anti-tumor activity used in treatment of various cancers. A number of studies have demonstrated the potential of Res in regulation of molecular pathways involved in cancer malignancy. At the present review, we show that Res targets a variety of signaling pathways to induce apoptotic cell death and simultaneously, to inhibit the migration and metastasis of GC cells.

PHB2 promotes tumorigenesis via RACK1 in non-small cell lung cancer

Background: Lung cancer has the highest mortality rate among cancers worldwide, with non-small cell lung cancer (NSCLC) the most common type. Increasing evidence shows that PHB2 is highly expressed in other cancer types; however, the effects of PHB2 in NSCLC are currently poorly understood.

Method: PHB2 expression and its clinical relevance in NSCLC tumor tissues were analyzed using a tissue microarray. The biological role of PHB2 in NSCLC was investigated in vitro and in vivo using immunohistochemistry and immunofluorescence staining, gene expression knockdown and overexpression, cell proliferation assay, flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, wound healing assay, Transwell assay, western blot analysis, qRT-PCR, coimmunoprecipitation, and mass spectrometry analysis.

Results: Our major finding is that PHB2 facilitates tumorigenesis in NSCLC by interacting with and stabilizing RACK1, which further induces activation of downstream tumor-promoting effectors. PHB2 was found to be overexpressed in NSCLC tumor tissues, and its expression was correlated with clinicopathological features. Furthermore, PHB2 overexpression promoted proliferation, migration, and invasion, whereas PHB2 knockdown enhanced apoptosis in NSCLC cells. The stimulating effect of PHB2 on tumorigenesis was also verified in vivo. In addition, PHB2 interacted with RACK1 and increased its expression through posttranslational modification, which further induced activation of the Akt and FAK pathways.

Conclusions: Our results reveal the effects of PHB2 on tumorigenesis and its regulation of RACK1 and RACK1-associated proteins and downstream signaling in NSCLC. We believe that the crosstalk between PHB2 and RACK1 provides us with a great opportunity to design and develop novel therapeutic strategies for NSCLC.

Wnt-regulating microRNAs role in gastric cancer malignancy

Gastric cancer (GC) is responsible for high morbidity and mortality worldwide. This cancer claims fifth place among other cancers. There are a number of factors associated with GC development such as alcohol consumption and tobacco smoking. It seems that genetic factors play significant role in GC malignancy and progression. MicroRNAs (miRs) are short non-coding RNA molecules with negative impact on the expression of target genes. A variety of studies have elucidated the potential role of miRs in GC growth. Investigation of molecular pathways has revealed that miRs function as upstream modulators of Wnt signaling pathway. This signaling pathway involves in important biological processes such as cell proliferation and differentiation, and its dysregulation is associated with GC invasion. At the present review, we demonstrate that how miRs regulate Wnt signaling pathway in GC malignancy.

Overexpression of long non-coding RNA RP11-363E7.4 inhibits proliferation and invasion in gastric cancer

LncRNA RP11‐363E7.4 has been shown to be downregulated in gastric cancer (GC), while the effect of lncRNA RP11‐363E7.4 on GC and its potential molecular mechanisms is unclear. The purpose of this study was to explore the functional role and underlying molecular mechanisms of lncRNA RP11‐363E7.4 involved in GC progress.To address the question, quantitative real‐time PCR assay was performed to confirm lncRNA RP11‐363E7.4 expression levels in GC tissues and cell lines. Cell proliferation, apoptosis, migration and invasion were estimated using Cell Counting Kit‐8, colony formation, scratch wound healing and Transwell assays. Potential molecular mechanisms were evaluated using western blot assay. The results showed that lncRNA RP11‐363E7.4 was significantly downregulated in GC cell lines and 82 paired tissues. The correlation between expression and clinicopathological features indicated that low expression of lncRNA RP11‐363E7.4 was associated with T stage (P = .010). Functional experiments showed that overexpression of lncRNA RP11‐363E7.4 prevented proliferation, migration, and invasion and induced apoptosis of GC cells. Western blot assay revealed that lncRNA RP11‐363E7.4 functioned via the p53, Bax/Bcl‐2, β‐catenin pathway. In summary, this study revealed that lncRNA RP11‐363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. Significance of the study:LncRNA RP11‐363E7.4 has been shown to be downregulated in GC, while the effect of lncRNA RP11‐363E7.4 on GC and its potential molecular mechanism is unclear. We revealed that lncRNA RP11‐363E7.4 functioned as a tumour suppressor by inhibiting proliferation, migration, and invasion and inducing apoptosis of GC cells. LncRNA RP11‐363E7.4 might become an attractive diagnostic and prognostic biomarker of GC and a promising target for GC treatment.

CXCL8 Promotes Glioma Progression By Activating The JAK/STAT1/HIF-1α/Snail Signaling Axis

Background

Upregulation of CXCL8 (C-X-C motif ligand 8) in tumor cells has been reported in several types of cancer, and it correlates with a poor prognosis. However, the role of CXCL8 in glioma progression remains unknown.

Materials and methods

In this study, we examined CXCL8 expression levels in human glioma cell lines and in sixteen human gliomas with different grades. The molecular role of CXCL8 in glioma cells was investigated using quantitative polymerase chain reaction (qRT-PCR) assays, Western blotting, CCK-8 assays, EdU assays, colony formation assays, Transwell migration and invasion assays.

Results

We found that high expression levels of CXCL8 were positively associated with progression and poor prognosis in human glioma. Mechanistically, CXCL8 promoted the epithelial-mesenchymal transition (EMT) in glioma cells by activating the JAK/STAT1/HIF-1α/Snail signaling pathway.

Conclusion

Taken together, our data provide a plausible mechanism for CXCL8-modulated glioma progression, which suggests that CXCL8 may represent a potential therapeutic target in the prevention and treatment of gliomas.