Altered expression of endogenous soluble vascular endothelial growth factor receptor-2 is involved in the progression of esophageal squamous cell carcinoma

TAPI-1 Exhibits Anti-tumor Efficacy in Human Esophageal Squamous Cell Carcinoma Cells via Suppression of NF-κB Signaling Pathway

BACKGROUND

TNF-α processing inhibitor-1 (TAPI-1) is a known metalloproteinase inhibitor with potential anti-inflammatory effects. However, its anti-cancer effects on esophageal squamous cell carcinoma (ESCC) have not been uncovered.

AIM

In the present study, the effects of TAPI-1 on ESCC cell viability, migration, invasion, and cisplatin resistance and the underlying molecular mechanisms were investigated in TE-1 and Eca109 cells.

METHODS

To this end, TE-1 and Eca109 cells were exposed to TAPI-1 for indicated time intervals. Cell viability was assessed using cell counting kit-8 assay and apoptosis was evaluated using flow cytometry assay. Migration and invasion were assessed using Transwell assays. Gene expressions were analyzed using quantitative reverse transcription polymerase chain reaction. The activation of NF-κB signaling pathway was elucidated via Western blot and chromatin immunoprecipitation assay.

RESULTS

We observed that higher doses (10, 20 μM) of TAPI-1 inhibited ESCC cell viability, while a lower dose (5 μM) of TAPI-1 inhibited ESCC cell migration and invasion and enhanced the chemosensitivity of ESCC cells to cisplatin. Moreover, TAPI-1 suppressed the activation of NF-κB signaling and the target genes expression in the stage of transcription initiation. Furthermore, blocking NF-κB signaling in advance could abolish all the effects of TAPI-1 on ESCC cells.

CONCLUSION

Overall, these results indicated that TAPI-1 impairs ESCC cell viability, migration, and invasion and facilitates cisplatin-induced apoptosis via suppression of NF-κB signaling pathway. TAPI-1 may serve as a potential adjuvant agent with cisplatin for ESCC therapy.

ADAM17 and NF-κB p65 form a positive feedback loop that facilitates human esophageal squamous cell carcinoma cell viability

A Disintegrin and metalloproteinase 17 (ADAM17) was proposed to cooperate with NF-κB p65, promoting tumorigenesis and progression of several human cancers. However, the role of ADAM17 remains unknown in human esophageal squamous cell carcinoma (ESCC). In this study, gene expression analyses and cell viability assays suggested that knockdown of ADAM17 suppressed ESCC cell viability. Gene expression analyses and ChIP-qPCR revealed that NF-κB p65 positively regulated ADAM17 expression by binding to the ADAM17 promoter. Rescue experiments showed that overexpression of ADAM17 in NF-κB p65-depleted ESCC cells restored cell viability. In addition, western blot analyses and ChIP-qPCR indicated that ADAM17 was responsible for the persistent activation of NF-κB p65 and contributed to ADAM17 expression in ESCC cells. In conclusion, we propose that ADAM17-activated NF-κB p65 signaling positively regulates ADAM17 expression, and facilitates ESCC cell viability.

Alterations of RNA splicing patterns in esophagus squamous cell carcinoma

Alternative splicing (AS) is an important biological process for regulating the expression of various isoforms from a single gene and thus to promote proteome diversity. In this study, RNA-seq data from 15 pairs of matched esophageal squamous cell carcinoma (ESCC) and normal tissue samples as well as two cell lines were analyzed. AS events with significant differences were identified between ESCC and matched normal tissues, which were re-annotated to find protein coding genes or non-coding RNAs. A total of 45,439 AS events were found. Of these, 6019 (13.25%) significant differentially AS events were identified. Exon skipping (SE) events occupied the largest proportion of abnormal splicing events. Fifteen differential splicing events with the same trends of ΔΨ values in ESCC tissues, as well in the two cell lines were found. Four pathways and 20 biological processes related to pro-metastasis cell junction and migration were significantly enriched for the differentially spliced genes. The upregulated splicing factor SF3B4, which regulates 92 gene splicing events, could be a potential prognostic factor of ESCC. Differentially spliced genes, including HNRNPC, VCL, ZNF207, KIAA1217, TPM1 and CALD1 are shown with a sashimi plot. These results suggest that cell junction- and migration-related biological processes are influenced by AS abnormalities, and aberrant splicing events can be affected by splicing factor expression changes. The involved splicing factor SF3B4 was found to be a survival-related gene in ESCC and is presumed to regulate AS in multiple cancers. In summary, we identified significant differentially expressed AS events which may be related to the development of ESCC.

RAC1 inhibition reverses cisplatin resistance in esophageal squamous cell carcinoma and induces downregulation of glycolytic enzymes

Development of chemoresistance remains a major challenge in treating esophageal squamous cell carcinoma (ESCC) patients despite treatment advances. However, the role of RAC1 in chemoresistance of ESCC and the underlying mechanisms remain largely unknown. In this study, we found that higher levels of RAC1 expression were associated with poorer prognosis in ESCC patients. Enhanced RAC1 expression increased cell proliferation, migration, and chemoresistance in vitro. Combination therapy using RAC1 inhibitor EHop-016 and cisplatin significantly promoted cell viability inhibition, G2/M phase cycle arrest, and apoptosis when compared to each monotherapy. Mechanistically, glycolysis was significantly downregulated in the RAC1 inhibitor monotherapy group and the combination group via inhibiting AKT/FOXO3a signaling when compared to the control group. Moreover, the silencing of RAC1 inhibited AKT/FOXO3a signaling and cell glycolysis while the upregulation of RAC1 produced an opposite effect. In murine xenograft models, the tumor volume and the expression of glycolytic enzymes were significantly reduced in combination therapy when compared to each monotherapy group. Overall, our study demonstrates that targeting RAC1 with an inhibitor overcomes cisplatin resistance in ESCC by suppressing glycolytic enzymes, which provides a promising strategy for treatment of ESCC in clinical practice.

Elevated IL-7Rα is linked to recurrence and poorer survival of gastric adenocarcinoma

IL-7Rα expression has been suggested to be involved in the development of cancer and has been reported to be linked to poor overall survival in patients with lung cancer. However, no evidence has been reportedregarding the significance of IL-7Rα expression in gastric adenocarcinoma (GA) untilnow. In the present investigation, to understand the clinicopathological significance of IL-7Rα expression in GA, expression of IL-7Rα was evaluated using immunohistochemistry in 121 cases of paired GA and its corresponding normal controls. As further confirmation, detection of IL-7Rα expression was extended from the protein level to the mRNA level using qRT-PCR. Clinicopathological association was statistically analyzed between IL-7Rα expression and clinicopathological variables, including demographic, T classification, clinical stage, lymph nodes metastases, differentiation, recurrence or not, and overall prognosis. IL-7Rα expression was markedly up-regulated in GA tissues relative to paired normal controls at both the protein or mRNA level. Elevation of IL-7Rα was markedly associated with lymph nodes metastases (P=0.006), differentiation (P=0.005), recurrence (P=0.043), and poor overall prognosis (P=0.039). There were trends toward statistical significance forboth T classification (P=0.063) and clinical stage (P=0.065) despite no significant associations found. Together, our study is the first toanalyze the significance of IL-7Rα expression in GA, suggesting its potential predictive value for recurrence and overall prognosis.