Association between GPX3 promoter methylation and malignant tumors: A meta-analysis

Analyses of P16INK4a gene promoter methylation relative to molecular, demographic and clinical parameters characteristics in non-small cell lung cancer patients: A pilot study

BACKGROUND

The aim of this study was to examine the methylation status of p16^INK4a promoter region in non small cell lung cancer (NSCLC) patients and their associations with single nucleotide polymorphisms (SNPs) of the epidermal growth factor receptor (EGFR) gene, as well as with demographic or clinical characteristics.

METHODS

Formalin-fixed and paraffin-embedded (FFPE) DNA samples extracted from 22 NSCLC patients were analyzed with methylation-specific polymerase chain reaction (PCR) method to obtain promoter methylation profile. The same cohort was genotyped for - 216G > T, -191 C > A, and 181,946 C > T EGFR SNPs.

RESULTS

There was a significant association between methylated p16^INK4a in patients prior therapy (p = 0.017) since a significantly higher frequency of methylated p16^INK4a was detected in these patients (40.9%) in comparison to frequency in patients after therapy (31.8%). Also, a higher frequency of methylated p16^INK4a was detected among patients with leucopenia (p = 0.056). No associations were observed between the methylation status of the p16^INK4a promoter region and EGFR SNPs or other clinical and demographic data in this cohort.

CONCLUSION

High frequency of methylation of the p16^INK4a gene promoter was observed in NSCLC patients prior therapy and with leucopenia that can indicate their significance related to advanced clinical stage.

Short-chain L-3-hydroxyacyl-CoA dehydrogenase: A novel vital oncogene or tumor suppressor gene in cancers

The reprogramming of cellular metabolism is frequently linked to tumorigenesis. Glucose, fatty acids, and amino acids are the specific substrates involved in how an organism maintains metabolic equilibrium. The HADH gene codes for the short-chain L-3-hydroxyacyl-CoA dehydrogenase (HADH), a crucial enzyme in fatty acid oxidation that catalyzes the third phase of fatty acid oxidation in mitochondria. Increasing data suggest that HADH is differentially expressed in various types of malignancies and is linked to cancer development and progression. The significance of HADH expression in tumors and its potential mechanisms of action in the onset and progression of certain cancers are summarized in this article. The possible roles of HADH as a target and/or biomarker for the detection and treatment of various malignancies is also described here.

Insights into the role of GPX3, a highly efficient plasma antioxidant, in cancer

Glutathione peroxidases are well known antioxidant enzymes. They catalyze the reduction of hydrogen peroxide or organic hydroperoxides using glutathione. Among the reported 8 GPxs, GPx3, a highly conserved protein and a major ROS scavenger in plasma, has been well studied and confirmed to play a vital role as a tumor suppressor in most cancers. Additionally, this gene is known to be epigenetically regulated. It is downregulated either by hypermethylation or genomic deletion. In this review, we summarized the role of GPX3 in various cancers, its use as a prognostic biomarker, and a potential target for clinical intervention.

GPX3 methylation is associated with hematologic improvement in low-risk myelodysplastic syndrome patients treated with Pai-Neng-Da

Objective

The aim of this prospective randomized controlled clinical trial was to explore the relationship between GPX3 methylation and Pai-Neng-Da (PND) in the treatment of patients with low-risk myelodysplastic syndrome (MDS).

Methods

There were 82 low-risk MDS patients who were randomly divided into the following two groups: androl, thalidomide, and PND capsule (ATP group, n = 41); or androl and thalidomide (AT group, n = 41). Hemoglobin and neutrophil and platelet counts and changes in GPX3 methylation level were assessed.

Results

The plasma hemoglobin level increased in both groups after treatment. However, the platelet count increased only in the ATP group. Patients in the ATP group had a better platelet response than the AT group, and GPX3 methylation markedly decreased after treatment with ATP but not after treatment with AT. Moreover, male patients had a significantly lower GPX3 methylation level than female patients, while platelet counts from male patients increased dramatically after the ATP regimens compared with female patients. GPX3 methylation changes were negatively correlated with platelet changes in ATP group.

Conclusion

PND can improve hematological parameters and decrease the GPX3 methylation level. Decreasing GPX3 methylation is associated with the hematologic response that includes platelet in GPX3 methylation.

China Clinical Trial Bureau (ChiCTR;http://www.chictr.org.cn/) registration number: ChiCTR-IOR-15006635.

Increased glutathione utilization augments tumor cell proliferation in Waldenstrom Macroglobulinemia

Metabolic reprogramming is a hallmark of cancer cells. In Waldenstrom Macroglobulinemia (WM), the infiltration of IgM-secreting lymphoplamacytic cells into the bone marrow (BM) could shift the homeostasis of proteins and metabolites towards a permissive niche for tumor growth. Here, we investigated whether alerted metabolic pathways contribute to the pathobiology of WM and whether the cytokine composition of the BM promotes such changes. Metabolomics analysis on WM patients and normal donors' serum samples revealed a total of 75 metabolites that were significantly altered between two groups. While these metabolites belonged to amino acids, glucose, glutathione and lipid metabolism pathways, the highest number of the differentially expressed metabolites belonged to glutathione metabolism. Proteomics analysis and immunohistochemical staining both confirmed the increased protein levels mediating glutathione metabolism, including GCLC, MT1X, QPCT and GPX3. Moreover, treatment with IL-6 and IL-21, cytokines that induce WM cell proliferation and IgM secretion, increased gene expression of the amino acid transporters mediating glutathione metabolism, including ASCT2, SLC7A11 and 4F2HC, indicating that cytokines in the WM BM could modulate glutathione metabolism. Glutathione synthesis inhibition using Buthionine sulphoximine (BSO) significantly reduced WM cells proliferation in vitro, accompanied with decreased NFκB-p65 and MAPK-p38 phosphorylation. Moreover, BSO treatment significantly reduced the tumor growth rate in a WM xenograft model, further highlighting the role of glutathione metabolism in promoting tumor growth and proliferation. In summary, our data highlight a central role for glutathione metabolism in WM pathobiology and indicate that intervening with the metabolic processes could be a potential therapy for WM patients.

Identification the prognostic value of glutathione peroxidases expression levels in acute myeloid leukemia

Background

Glutathione peroxidases (GPXs) are an enzyme family with peroxidase activity. Abnormal GPX expression is associated with carcinogenesis. However, the potential role of the GPX gene family in acute myeloid leukemia (AML) remains to be comprehensively examined.

Methods

We analyzed GPX mRNA expression levels and determined the correlation between gene expression and the prognostic value via multiple universally acknowledged databases including the Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), PROGgeneV2, UALCAN, Cancer Cell Line Encyclopedia (CCLE), and The European Bioinformatics Institute (EMBL-EBI) databases. The functional network of differentially expressed GPXs was investigated via the NetworkAnalyst platform. Correlated genes as well as kinase, microRNA (miRNA), and transcription factor (TF) targets were identified using LinkedOmics.

Results

We observed that the transcriptional expression levels of GPX-1, -2, -4, -7, and -8 had significant difference between AML patients samples and normal samples, and that AML patients with high expression of GPX-1, -3, -4, and -7 were associated with poorer prognosis of overall survival (OS). Functional enrichment analysis showed that the differentially expressed GPXs were mainly enriched in response to oxidative stress, regulation of immune response, and inflammatory response, along with glutathione metabolism and ferroptosis. Overexpression of correlated genes, PSMB10, VPS13D, NDUFS8, ATP5D, POLR2E, and HADH were linked to adverse OS in AML. Regulatory network analysis indicated that differentially expressed GPXs regulated cell proliferation, cancer progression, apoptosis, and cell cycle signaling via pathways involving cancer-related kinases (such as DAPK1 and SRC), miRNAs (such as miR-202 and miR-181), and TFs (such as SRF and E2F1).

Conclusions

Our findings offer novel insights into the differential expression and prognostic potential of the GPX family in AML, and lay a foundation for subsequent research of GPX’s role in the carcinogenesis and regulatory network of AML.

LRRC19-A Bridge between Selenium Adjuvant Therapy and Renal Clear Cell Carcinoma: A Study Based on Datamining

Kidney renal clear cell carcinoma (KIRC) is the most common and fatal subtype of renal cancer. Antagonistic associations between selenium and cancer have been reported in previous studies. Selenium compounds, as anti-cancer agents, have been reported and approved for clinical trials. The main active form of selenium in selenoproteins is selenocysteine (Sec). The process of Sec biosynthesis and incorporation into selenoproteins plays a significant role in biological processes, including anti-carcinogenesis. However, a comprehensive selenoprotein mRNA analysis in KIRC remains absent. In the present study, we examined all 25 selenoproteins and identified key selenoproteins, glutathione peroxidase 3 (GPX3) and type 1 iodothyronine deiodinase (DIO1), with the associated prognostic biomarker leucine-rich repeat containing 19 (LRRC19) in clear cell renal cell carcinoma cases from The Cancer Genome Atlas (TCGA) database. We performed validations for the key gene expression levels by two individual clear cell renal cell carcinoma cohorts, GSE781 and GSE6344, datasets from the Gene Expression Omnibus (GEO) database. Multivariate survival analysis demonstrated that low expression of LRRC19 was an independent risk factor for OS. Gene set enrichment analysis (GSEA) identified tyrosine metabolism, metabolic pathways, peroxisome, and fatty acid degradation as differentially enriched with the high LRRC19 expression in KIRC cases, which are involved in selenium therapy of clear cell renal cell carcinoma. In conclusion, low expression of LRRC19 was identified as an independent risk factor, which will advance our understanding concerning the selenium adjuvant therapy of clear cell renal cell carcinoma.

Prognostic implications of metabolism-associated gene signatures in colorectal cancer

Colorectal cancer (CRC) is one of the most common and deadly malignancies. Novel biomarkers for the diagnosis and prognosis of this disease must be identified. Besides, metabolism plays an essential role in the occurrence and development of CRC. This article aims to identify some critical prognosis-related metabolic genes (PRMGs) and construct a prognosis model of CRC patients for clinical use. We obtained the expression profiles of CRC from The Cancer Genome Atlas database (TCGA), then identified differentially expressed PRMGs by R and Perl software. Hub genes were filtered out by univariate Cox analysis and least absolute shrinkage and selection operator Cox analysis. We used functional enrichment analysis methods, such as Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis, to identify involved signaling pathways of PRMGs. The nomogram predicted overall survival (OS). Calibration traces were used to evaluate the consistency between the actual and the predicted survival rate. Finally, a prognostic model was constructed based on six metabolic genes (NAT2, XDH, GPX3, AKR1C4, SPHK1, and ADCY5), and the risk score was an independent prognostic prognosticator. Genetic expression and risk score were significantly correlated with clinicopathologic characteristics of CRC. A nomogram based on the clinicopathological feature of CRC and risk score accurately predicted the OS of individual CRC cancer patients. We also validated the results in the independent colorectal cancer cohorts GSE39582 and GSE87211. Our study demonstrates that the risk score is an independent prognostic biomarker and is closely correlated with the malignant clinicopathological characteristics of CRC patients. We also determined some metabolic genes associated with the survival and clinical stage of CRC as potential biomarkers for CRC diagnosis and treatment.

The value of endothelin receptor type B promoter methylation as a biomarker for the risk assessment and diagnosis of prostate cancer: A meta-analysis

Previous researches have demonstrated that the methylation status of the EDNRB promoter was associated with the prostate cancer (PCa), but these conclusions remained controversial. Thus, the aim of this meta-analysis was to evaluate the association between EDNRB promoter methylation and the PCa. According to the PRISMA statement, the Web of Science, PubMed, EMBASE, and Cochrane Library databases were retrieved. The ORs and 95 % CIs were analyzed to evaluate the associations between EDNRB promoter methylation and the risk and clinical features of PCa. Heterogeneity among the included studies was estimated by I² statistic and Q test. Publication bias and sensitivity analysis were utilized to test the robustness of our outcomes. In addition, the pooled sensitivity and specificity were calculated to assess the diagnostic value of EDNRB methylation for PCa. Ultimately, 11 eligible studies were included. Under the random-effects model, the pooled OR shown that the frequency of EDNRB methylation was substantially higher in cases compared with controls (OR = 5.42, 95 % CI = 1.98-14.88, P = 0.001). The similar results were also found by the data from TCGA database. Subgroup analysis according to the methylation detection method showed that the heterogeneity in quantitative methylation-specific polymerase chain reaction (qMSP) group was insignificant (I² = 0.0 %, P = 0.669). Moreover, the pooled sensitivity for all-inclusive studies was 0.55 (95 % CI: 0.26-0.81), and the pooled specificity was 0.93 (95 % CI: 0.55-0.99). The methylation of EDNRB promoter might increase the risk of PCa. Meanwhile, EDNRB promoter methylation test combined with PSA testing and/or other biomarkers could be promising diagnostic biomarkers for more accurate detection of PCa.

Promoter methylation and clinical significance of GPX3 in esophageal squamous cell carcinoma

BACKGROUND

Glutathione peroxidase 3 (GPX3) provides critical protection against reactive oxygen species (ROS) in cells. Downregulation of GPX3 may contribute to carcinogenesis of esophageal squamous cell carcinoma (ESCC), but the mechanisms are not clear.

MATERIALS AND METHODS

We examined the differences in gene expression between ESCC and normal esophageal epithelial, by using GEO datasets, and collected 136 ESCC tumors and adjacent normal tissues to confirm our findings. GPX3 expression was measured, at the mRNA and protein levels, by qRT-PCR, Western Blot and immunohistochemistry (IHC).

RESULTS

GPX3 mRNA and protein levels were 3.3-fold higher in normal epithelium compared with case-matched ESCC tissues. There was no significant correlation between clinical parameters and expression levels of GPX3 in ESCC. Promoter methylation of the GPX3 gene correlated with decreased expression.

CONCLUSION

Downregulation of GPX3 might be a key factor in the process of ESCC carcinogenesis.