TGIF1 plays a carcinogenic role in esophageal squamous cell carcinoma through the Wnt/β‑catenin and Akt/mTOR signaling pathways

Inhibition of ERN1 affects the expression of TGIF1 and other homeobox gene expressions in U87MG glioblastoma cells

BACKGROUND

The ERN1 (endoplasmic reticulum to nucleus signaling 1) pathway plays an important role in the regulation of gene expression in glioblastoma, but molecular mechanism has not yet been fully elucidated. The aim of this study was to evaluate the relative relevance of ERN1 activity as a kinase in comparison to its endoribonuclease activity in the regulation of homeobox gene expression.

METHODS

Two sublines of U87MG glioblastoma cells with different ways of ERN1 inhibition were used: dnERN1 (overexpressed transgene without protein kinase and endoribonuclease) and dnrERN1 (overexpressed transgene with mutation in endoribonuclease). ERN1 suppression was also done using siRNA for ERN1. Silencing of XBP1 mRNA by specific siRNA was used for suppression of ERN1 endoribonuclease function mediated by XBP1s. The expression levels of homeobox genes and microRNAs were evaluated by qPCR.

RESULTS

The expression of TGIF1 and ZEB2 genes was downregulated in both types of glioblastoma cells with inhibition of ERN1 showing the ERN1 endoribonuclease-dependent mechanism of their regulation. However, the expression of PBX3 and PRPRX1 genes did not change significantly in dnrERN1 glioblastoma cells but was upregulated in dnERN1 cells indicating the dependence of these gene expressions on the ERN1 protein kinase. At the same time, the changes in PAX6 and PBXIP1 gene expressions introduced in glioblastoma cells by dnrERN1 and dnERN1 were different in direction and magnitude indicating the interaction of ERN1 protein kinase and endoribonuclease activities in regulation of these gene expressions. The impact of ERN1 and XBP1 silencing on the expression of studied homeobox genes is similar to that observed in dnERN1 and dnrERN1 glioblastoma cells, correspondingly.

CONCLUSION

The expression of TGIF1 and other homeobox genes is dependent on the ern1 signaling pathways by diverse mechanisms because inhibition of ERN1 endoribonuclease and both ERN1 enzymatic activities had dissimilar impacts on the expression of most studied genes showing that ERN1 protein kinase plays an important role in controlling homeobox gene expression associated with glioblastoma cell invasion.

[Effect of CircCCND1 on the Malignant Biological Behaviors of H446 Lung Cancer Cells by Regulating the MiR-340-5p/TGIF1 Axis]

BACKGROUND

Lung cancer is a common malignant tumor of the lung. To explore the molecular mechanism of the occurrence and development of lung cancer is a hot topic in current research. Cyclic RNA D1 (CircCCND1) is highly expressed in lung cancer and may be a potential target for the treatment of lung cancer. The aim of this study was to investigate the effect of CircCCND1 on the malignant biological behaviors of lung cancer cells by regulating the miR-340-5p/transforming growth factor β-induced factor homeobox 1 (TGIF1) axis.

METHODS

The expression of CircCCND1, miR-340-5p, and TGIF1 mRNA in human normal lung epithelial cells BEAS-2B and human lung cancer H446 cells were detected. H446 cells cultured in vitro were randomly divided into control group, CircCCND1 siRNA group, miR-340-5p mimics group, negative control group, and CircCCND1 siRNA+miR-340-5p inhibitor group. Cell proliferation, mitochondrial membrane potential, apoptosis, migration, and invasion were detected, and the expressions of CircCCND1, miR-340-5p, TGIF1 mRNA, BCL2-associated X protein (Bax), cleaved Caspase-3, N-cadherin, E-cadherin, and TGIF1 proteins in each group were detected. The targeting relationship of miR-340-5p with CircCCND1 and TGIF1 was verified.

RESULTS

Compared with BEAS-2B cells, CircCCND1 and TGIF1 mRNA were increased in H446 cells, and miR-340-5p expression was decreased (P<0.05). Knocking down CircCCND1 or up-regulating the expression of miR-340-5p inhibited the proliferation, migration and invasion of H446 cells, decreased the expression of TGIF1 mRNA and TGIF1 protein, and promoted cell apoptosis. Down-regulation of miR-340-5p could antagonize the inhibitory effect of CircCCND1 knockdown on the malignant biological behavior of H446 lung cancer cells. CircCCND1 may target the down-regulation of miR-340-5p, and miR-340-5p may target the down-regulation of TGIF1.

CONCLUSIONS

Knocking down CircCCND1 can inhibit the malignant behaviors of lung cancer H446 cells, which may be achieved through the regulation of miR-340-5p/TGIF1 axis.

CBX8 Promotes Epithelial-mesenchymal Transition, Migration, and Invasion of Lung Cancer through Wnt/β-catenin Signaling Pathway

BACKGROUND

Lung cancer (LC) is primarily responsible for cancer-related deaths worldwide. Epithelial-mesenchymal transition (EMT) is a process in which epithelial cells acquire mesenchymal features and is associated with the development of tumors. CBX8, a member of the PcG protein family, plays a critical role in various cancers, containing LC. However, specific regulatory mechanisms of CBX8 in LC progression are not fully understood. This study aimed to investigate the regulatory role of CBX8 in LC progression.

METHODS

Bioinformatics was used to analyze the relationship between CBX8 level and tumor and the enrichment pathway of CBX8 enrichment. qRT-PCR was used to detect the differential expression of CBX8 in LC cells and normal lung epithelial cells. The effects of knockdown or overexpression of CBX8 on the proliferation, migration and invasion of LC cells were evaluated by CCK- -8 assay and Transwell assay, and the levels of proteins associated with the EMT pathway and Wnt/ β-catenin signaling pathway were detected by western blot.

RESULTS

Bioinformatics analysis revealed that CBX8 was highly expressed in LC and enriched on the Wnt/β-catenin signaling pathway. The expression level of CBX8 was significantly elevated in LC cells. Knockdown of CBX8 significantly inhibited cell proliferation, migration and invasion, and decreased the expression levels of EMT-related proteins and Wnt/β-catenin pathway-related proteins. Conversely, overexpression of CBX8 promoted cell proliferation, migration and invasion, and increased the expression levels of EMT-related proteins and Wnt/β-catenin pathway-related proteins. The Wnt inhibitor IWP-4 alleviated the effects produced by overexpression of CBX8.

CONCLUSION

Collectively, these data demonstrated that CBX8 induced EMT through Wnt/β-- catenin signaling, driving migration and invasion of LC cells.

PHGDH promotes esophageal squamous cell carcinoma progression via Wnt/β-catenin pathway

PURPOSE

Esophageal squamous carcinoma (ESCC) with a high incidence in China, lacks effective therapeutic targets. Phosphoglycerate dehydrogenase (PHGDH) is a key enzyme in serine biosynthesis. However, the biological role of PHGDH in ESCC has not been revealed.

METHODS

The expression of PHGDH in ESCC was investigated by UALCAN. The relationship between PHGDH expression and its prognostic value was analyzed by Kaplan-Meier and univariate Cox regression. Further, the potential functions of PHGDH involved in ESCC were explored through DAVID database and GSEA software. In addition, the expression of PHGDH was verified in ESCC. Then, the effects of PHGDH knockdown on ESCC were evaluated in vitro and in vivo by cell proliferation, clone formation, cell cycle, apoptosis, tube formation assays and ESCC cells derived xenograft model. In addition, western blotting and immunohistochemistry were used to detect the expression of Wnt/β-catenin pathway which was associated with PHGDH.

RESULTS

Bioinformatics analysis found that PHGDH was highly expressed in ESCC, and meaningfully, patients with high PHGDH expression had a poor prognosis. Moreover, the overexpression of PHGDH was verified in ESCC. Afterwards, PHGDH knockdown inhibited the cell proliferation, induced cell cycle arrest and apoptosis in ESCC cells, and inhibited the angiogenesis of HUVECs induced by ESCC conditioned medium, as well as inhibited the growth of xenograft tumor. Mechanistically, PHGDH knockdown inhibited Wnt/β-catenin signaling pathway in ESCC.

CONCLUSION

High expression of PHGDH predicts a poor prognosis for ESCC. PHGDH knockdown inhibits ESCC progression by suppressing Wnt/β-catenin signaling pathway, indicating that PHGDH might be a potential target for ESCC therapy.

Roles of oncogenes in esophageal squamous cell carcinoma and their therapeutic potentials

Esophageal squamous cell carcinoma (ESCC) is the most common type of esophageal cancer (EC) in Asia. It is a malignant digestive tract tumor with abundant gene mutations. Due to the lack of specific diagnostic markers and early cancer screening markers, most patients are diagnosed at an advanced stage. Genetic and epigenetic changes are closely related to the occurrence and development of ESCC. Here, We review the activation of proto-oncogenes into oncogenes through gene mutation and gene amplification in ESCC from a genetic and epigenetic genome perspective, We also discuss the specific regulatory mechanisms through which these oncogenes mainly affect the biological function and occurrence and development of ESCC through specific regulatory mechanisms. In addition, we summarize the clinical application value of these oncogenes is summarized, and it provides a feasible direction for clinical use as potential therapeutic and diagnostic markers.