Upregulation of DUSP14 Affects Proliferation, Invasion and Metastasis, Potentially via Epithelial-Mesenchymal Transition and Is Associated with Poor Prognosis in Pancreatic Cancer

miR-199a-5p targets DUSP14 to regulate cell proliferation, invasion and stemness in non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) shows the highest morbidity among malignant tumors worldwide. Despite improvements of diagnosis and treatment, patient prognosis remains unfavorable. Therefore, there is a need to discover a novel treatment strategy for NSCLC. DUSP14 is related to various cancers as the regulatory factor for cellular processes. However, its specific roles in NSCLC and the upstream modulator remain largely unclear.

Methods

DUSP14 expression patterns within the lung cancer patient cohort from TCGA database were analyzed using UALCAN online tool. Different databases including miRDB, starbase, and Targetscan were employed to screen the upstream regulator of DUSP14. DUSP14 and miR-199a-5p expression was determined by qRT-PCR and Western blot techniques. To confirm binding interaction of DUSP14 with miR-199a-5p, we conducted a dual-luciferase reporter assay. Cell viability, migration, and stemness properties were assessed using CCK-8, EdU (5-ethynyl-2'-deoxyuridine) incorporation, transwell invasion, and sphere formation assays. The effect of DUSP14 silencing on tumorigenesis was assessed with the NSCLC cell xenograft mouse model.

Results

Our study discovered that DUSP14 exhibited high expression within NSCLC tumor samples, which is related to the dismal prognostic outcome in NSCLC patients. Silencing DUSP14 impaired NSCLC cell proliferation, migration, and tumor sphere formation. Besides, we identified miR-199a-5p as the upstream regulatory factor for DUSP14, and its expression was negatively related to DUSP14 level within NSCLC tissues. Introducing miR-199a-5p recapitulated the function of DUSP14 silencing in NSCLC cell aggressiveness and stemness. Moreover, knocking down DUSP14 efficiently inhibited tumor formation in NSCLC cells of the xenograft model.

Conclusions

Our study suggests that DUSP14 is negatively regulated by miR-199a-5p within NSCLC, whose overexpression is required for sustaining NSCLC cell proliferation, invasion and stemness.

Genetic predisposition to lung adenocarcinoma outcome is a feature already present in patients' noninvolved lung tissue

Emerging evidence suggests that the prognosis of patients with lung adenocarcinoma can be determined from germline variants and transcript levels in nontumoral lung tissue. Gene expression data from noninvolved lung tissue of 483 lung adenocarcinoma patients were tested for correlation with overall survival using multivariable Cox proportional hazard and multivariate machine learning models. For genes whose transcript levels are associated with survival, we used genotype data from 414 patients to identify germline variants acting as cis-expression quantitative trait loci (eQTLs). Associations of eQTL variant genotypes with gene expression and survival were tested. Levels of four transcripts were inversely associated with survival by Cox analysis (CLCF1, hazard ratio [HR] = 1.53; CNTNAP1, HR = 2.17; DUSP14, HR = 1.78; and MT1F: HR = 1.40). Machine learning analysis identified a signature of transcripts associated with lung adenocarcinoma outcome that was largely overlapping with the transcripts identified by Cox analysis, including the three most significant genes (CLCF1, CNTNAP1, and DUSP14). Pathway analysis indicated that the signature is enriched for ECM components. We identified 32 cis-eQTLs for CNTNAP1, including 6 with an inverse correlation and 26 with a direct correlation between the number of minor alleles and transcript levels. Of these, all but one were prognostic: the six with an inverse correlation were associated with better prognosis (HR < 1) while the others were associated with worse prognosis. Our findings provide supportive evidence that genetic predisposition to lung adenocarcinoma outcome is a feature already present in patients' noninvolved lung tissue.

Protein tyrosine phosphatome metabolic screen identifies TC-PTP as a positive regulator of cancer cell bioenergetics and mitochondrial dynamics

Metabolic reprogramming occurs in cancer cells and is regulated partly by the opposing actions of tyrosine kinases and tyrosine phosphatases. Several members of the protein tyrosine phosphatase (PTP) superfamily have been linked to cancer as either pro-oncogenic or tumor-suppressive enzymes. In order to investigate which PTPs can modulate the metabolic state of cancer cells, we performed an shRNA screen of PTPs in HCT116 human colorectal cancer cells. Among the 72 PTPs efficiently targeted, 24 were found to regulate mitochondrial respiration, 8 as negative and 16 as positive regulators. Of the latter, we selected TC-PTP (PTPN2) for further characterization since inhibition of this PTP resulted in major functional defects in oxidative metabolism without affecting glycolytic flux. Transmission electron microscopy revealed an increase in the number of damaged mitochondria in TC-PTP-null cells, demonstrating the potential role of this PTP in regulating mitochondrial homeostasis. Downregulation of STAT3 by siRNA-mediated silencing partially rescued the mitochondrial respiration defect observed in TC-PTP-deficient cells, supporting the role of this signaling axis in regulating mitochondrial activity. In addition, mitochondrial stress prevented an increased expression of electron transport chain-related genes in cells with TC-PTP silencing, correlating with decreased ATP production, cellular proliferation, and migration. Our shRNA-based metabolic screen revealed that PTPs can serve as either positive or negative regulators of cancer cell metabolism. Taken together, our findings uncover a new role for TC-PTP as an activator of mitochondrial metabolism, validating this PTP as a key target for cancer therapeutics.

An Integrated Data Analysis of mRNA, miRNA and Signaling Pathways in Pancreatic Cancer

Although many genes and miRNAs have been reported for various cancers, pancreatic cancer's specific genes or miRNAs have not been studied precisely yet. Therefore, we have analyzed the gene and miRNA expression profile of pancreatic cancer data in the gene expression omnibus (GEO) database. The microarray-derived miRNAs and mRNAs were annotated by gene ontology (GO) and signaling pathway analysis. We also recognized mRNAs that were targeted by miRNA through the mirDIP database. An integrated analysis of the microarray revealed that only 6 out of 43 common miRNAs had significant differences in their expression profiles between the tumor and normal groups (P value < 0.05 and |log Fold Changes (logFC)|> 1). The hsa-miR-210 had upregulation, whereas hsa-miR-375, hsa-miR-216a, hsa-miR-217, hsa-miR-216b and hsa-miR-634 had downregulation in pancreatic cancer (PC). The analysis results also revealed 109 common mRNAs by microarray and mirDIP 4.1 databases. Pathway analysis showed that amoebiasis, axon guidance, PI3K-Akt signaling pathway, absorption and focal adhesion, adherens junction, platelet activation, protein digestion, human papillomavirus infection, extracellular matrix (ECM) receptor interaction, and riboflavin metabolism played important roles in pancreatic cancer. GO analysis revealed the significant enrichment in the three terms of biological process, cellular component, and molecular function, which were identified as the most important processes associated strongly with pancreatic cancer. In conclusion, DTL, CDH11, COL5A1, ITGA2, KIF14, SMC4, VCAN, hsa-mir-210, hsa-mir-217, hsa-mir-216a, hsa-mir-216b, hsa-mir-375 and hsa-mir-634 can be reported as the novel diagnostic or even therapeutic markers for the future studies. Also, the hsa-mir-107 and hsa-mir-125a-5p with COL5A1, CDH11 and TGFBR1 genes can be introduced as major miRNA and genes on the miRNA-drug-mRNA network. The new regulatory network created in our study could give a deeper knowledge of the pancreatic cancer.