Downregulation of glutathione peroxidase 3 is associated with lymph node metastasis and prognosis in cervical cancer

Circumventing drug resistance in gastric cancer: A spatial multi-omics exploration of chemo and immuno-therapeutic response dynamics

BACKGROUND

Gastric Cancer (GC) characteristically exhibits heterogeneous responses to treatment, particularly in relation to immuno plus chemo therapy, necessitating a precision medicine approach. This study is centered around delineating the cellular and molecular underpinnings of drug resistance in this context.

METHODS

We undertook a comprehensive multi-omics exploration of postoperative tissues from GC patients undergoing the chemo and immuno-treatment regimen. Concurrently, an image deep learning model was developed to predict treatment responsiveness.

RESULTS

Our initial findings associate apical membrane cells with resistance to fluorouracil and oxaliplatin, critical constituents of the therapy. Further investigation into this cell population shed light on substantial interactions with resident macrophages, underscoring the role of intercellular communication in shaping treatment resistance. Subsequent ligand-receptor analysis unveiled specific molecular dialogues, most notably TGFB1-HSPB1 and LTF-S100A14, offering insights into potential signaling pathways implicated in resistance. Our SVM model, incorporating these multi-omics and spatial data, demonstrated significant predictive power, with AUC values of 0.93 and 0.84 in the exploration and validation cohorts respectively. Hence, our results underscore the utility of multi-omics and spatial data in modeling treatment response.

CONCLUSION

Our integrative approach, amalgamating mIHC assays, feature extraction, and machine learning, successfully unraveled the complex cellular interplay underlying drug resistance. This robust predictive model may serve as a valuable tool for personalizing therapeutic strategies and enhancing treatment outcomes in gastric cancer.

Multiple approaches revealed MGc80-3 as a somatic hybrid with HeLa cells rather than a gastric cancer cell line

The short-tandem-repeats (STR) profiles of MGc80-3 and HeLa partially overlap, raising suspicion of contamination in the MGc80-3 cell line. However, there has not been any relevant study demonstrating whether MGc80-3 was fully replaced by HeLa cells, just mixed with HeLa cells (co-existing), or was a somatic hybrid with HeLa cells. In addition to STR profiling, various approaches, including single nucleotide polymorphisms genotyping, polymerase chain reaction, screening for human papillomaviruses type 18 (HPV-18) fragment, chromosome karyotyping, pathological examination of xenografts, tissue-specific-90-gene expression signature and high-throughput RNA sequencing were used to determine the nature of MGc80-3. Our study found that the abnormal STR profile, partially overlapping with that of HeLa cells (64.62% to 71.64%), could not verify MGc80-3 as a HeLa cell line. However, the STR 13.3 repeat allele in the D13S317 locus that seemed to be unique to HeLa cells was detected in MGc80-3. Almost all the MGc80-3 cells exhibited HPV-18 fragments in the genome as well as certain HeLa marker chromosomes, such as M7 and M12. The molecular assay of the 90-gene expression signature still considered MGc80-3 as a stomach cancer using an algorithmic analysis. The expression pattern of multiple genes in MGc80-3 was quite different from that in HeLa cells, which showed that certain characteristics belonged to gastric cancer cell lines. High throughput RNA sequencing showed the distinct patterns of gene expression in MGc80-3. In conclusion, MGc80-3 cell line is a somatic hybrid with HeLa cells rather than a pure gastric cancer cell line.

The analysis of HPV integration sites based on nanopore sequencing and the profiling changes along the course of photodynamic therapy

OBJECTIVE

To detect the HPV genotype and integration sites in patients with high-risk HPV infection at different stages of photodynamic therapy using nanopore technology and to evaluate the treatment effect.

METHODS

Four patients with HPV infection were selected and subjected to photodynamic therapy, and cervical exfoliated cell was sampled at before treatment, after three courses of treatment and six courses of treatment, their viral abundance and insertion sites were analyzed by nanopore technology, and pathological examinations were performed before and after treatment. In this study, we developed a novel assay that combined viral sequence enrichment and Nanopore sequencing for identification of HPV genotype and integration sites at once. The assay has obvious advantages over qPCR or NGS-based methods, as it has better sensitivity after viral sequences enrichment and can generate long-reads (kb to Mb) for better detection rate of structure variations, moreover, fast turn-around time for real-time viral sequencing and analysis.

RESULTS

The pathological grade was reduced in all four patients after photodynamic therapy. Virus has been cleared in two cases after treatment, the virus amount reduced after treatment but not completely cleared in one case, and two type viruses were cleared and one type virus persisted after treatment in the last patient with multiple infection. Viral abundance and the number of integration sites were positively correlated. Gene enrichment analysis showed complete viral clearance in 1 patient and 3 patients required follow-up.

CONCLUSION

Nanopore sequencing can effectively monitor the abundance of HPV viruses and integration sites to show the presence status of viruses, and combined with the results of gene enrichment analysis, the treatment effect can be dynamically assessed.

GPX3 expression was down-regulated but positively correlated with poor outcome in human cancers

Introduction

Cancer is a crucial public health problem and one of the leading causes of death worldwide. Previous studies have suggested that GPX3 may be involved in cancer metastasis and chemotherapy resistance. However, how GPX3 affects cancer patients' outcomes and the underlying mechanism remains unclear.

Methods

Sequencing data and clinical data from TCGA, GTEx, HPA, and CPTAC were used to explore the relationship between GPX3 expression and clinical features. Immunoinfiltration scores were used to assess the relationship between GPX3 and the tumor immune microenvironment. Functional enrichment analysis was used to predict the role of GPX3 in tumors. Gene mutation frequency, methylation level, and histone modification were used to predict the GPX3 expression regulation method. Breast, ovarian, colon, and gastric cancer cells were used to investigate the relationship between GPX3 expression and cancer cell metastasis, proliferation, and chemotherapy sensitivity.

Results

GPX3 is down-regulated in various tumor tissues, and GPX3 expression level can be used as a marker for cancer diagnosis. However, GPX3 expression is associated with higher stage and lymph node metastasis, as well as poorer prognosis. GPX3 is closely related to thyroid function and antioxidant function, and its expression may be regulated by epigenetic inheritance such as methylation modification or histone modification. In vitro experiments, GPX3 expression is associated with cancer cell sensitivity to oxidant and platinum-based chemotherapy and is involved in tumor metastasis in oxidative environments.

Discussion

We explored the relationship between GPX3 and clinical features, immune infiltration characteristics, migration and metastasis, and chemotherapy sensitivities of human cancers. We further investigated the potential genetic and epigenetic regulation of GPX3 in cancer. Our results suggested that GPX3 plays a complicated role in the tumor microenvironment, simultaneously promoting metastasis and chemotherapy resistance in human cancers.

Loss of alcohol dehydrogenase 1B in cancer-associated fibroblasts: contribution to the increase of tumor-promoting IL-6 in colon cancer

BACKGROUND

Increases in IL-6 by cancer-associated fibroblasts (CAFs) contribute to colon cancer progression, but the mechanisms involved in the increase of this tumor-promoting cytokine are unknown. The aim of this study was to identify novel targets involved in the dysregulation of IL-6 expression by CAFs in colon cancer.

METHODS

Colonic normal (N), hyperplastic, tubular adenoma, adenocarcinoma tissues, and tissue-derived myo-/fibroblasts (MFs) were used in these studies.

RESULTS

Transcriptomic analysis demonstrated a striking decrease in alcohol dehydrogenase 1B (ADH1B) expression, a gene potentially involved in IL-6 dysregulation in CAFs. ADH1B expression was downregulated in approximately 50% of studied tubular adenomas and all T1-4 colon tumors, but not in hyperplastic polyps. ADH1B metabolizes alcohols, including retinol (RO), and is involved in the generation of all-trans retinoic acid (atRA). LPS-induced IL-6 production was inhibited by either RO or its byproduct atRA in N-MFs, but only atRA was effective in CAFs. Silencing ADH1B in N-MFs significantly upregulated LPS-induced IL-6 similar to those observed in CAFs and lead to the loss of RO inhibitory effect on inducible IL-6 expression.

CONCLUSION

Our data identify ADH1B as a novel potential mesenchymal tumor suppressor, which plays a critical role in ADH1B/retinoid-mediated regulation of tumor-promoting IL-6.

Integrated Proteotranscriptomics Reveals Differences in Molecular Immunity between Min and Large White Pig Breeds

Long-term selection or evolution is an important factor governing the development of disease resistance in pigs. To better clarify the molecular mechanisms underlying different levels of disease resistance, we used transcriptomics and proteomics analysis to characterize differences in the immunities between six resistant (Min pig) and six susceptible (Large White, LW) pigs which were raised in the same environment. A total of 135 proteins and 791 genes were identified as being differentially expressed between the Large White and Min pig groups. Protein expression clustering and functional analysis revealed that proteins related to immune system process, humoral immune response, the B cell receptor signaling pathway, lymphocyte-mediated immunity, and innate immune responses were more highly expressed in Min pigs. Transcriptome gene set enrichment analysis was used to reveal that pathways of cell adhesion molecules and antigen processing and presentation are significantly enriched in Min pigs. Integrated proteomics and transcriptomics data analysis identified 16 genes that are differentially expressed at both the mRNA and protein levels. In addition, 13 out of these 16 genes were related to the quantitative trait loci of immune diseases, including neural EGFL-like 2 (NELL2) and lactate dehydrogenase B (LDHB), which are involved in innate immunity. Correlation analysis between the genes/proteins and cytokines shows upregulated proteins in LW pigs in association with immunosuppressive/pro-inflammatory cytokines, such as interleukin (IL) 10, IL6, and tumor necrosis factor alpha. This was further validated using parallel reaction monitoring analysis. In summary, we discovered several potential candidate pathways and key genes/proteins involved in determining differences in disease resistance between the two studied pig breeds, which could provide new insights into the breeding of pigs for disease resistance.

Metabolism and Anticancer Mechanisms of Selocompounds: Comprehensive Review

Selenium (Se) is an essential micronutrient with several functions in cellular and molecular anticancer processes. There is evidence that Se depending on its chemical form and the dosage use could act as a modulator in some anticancer mechanisms. However, the metabolism of organic and inorganic forms of dietary selenium converges on the main pathways. Different selenocompounds have been reported to have crucial roles as chemopreventive agents, such as antioxidant activity, activation of apoptotic pathways, selective cytotoxicity, antiangiogenic effect, and cell cycle modulation. Nowadays, great interest has arisen to find therapies that could enhance the antitumor effects of different Se sources. Herein, different studies are reported related to the effects of combinatorial therapies, where Se is used in combination with proteins, polysaccharides, chemotherapeutic agents or as nanoparticles. Another important factor is the presence of single nucleotide polymorphisms in genes related to Se metabolism or selenoprotein synthesis which could prevent cancer. These studies and mechanisms show promising results in cancer therapies. This review aims to compile studies that have demonstrated the anticancer effects of Se at molecular levels and its potential to be used as chemopreventive and in cancer treatment.

Machine Learning and Novel Biomarkers Associated with Immune Infiltration for the Diagnosis of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) accounts for the main esophageal cancer type, which is related to advanced stage and poor survivals. Therefore, novel diagnostic biomarkers are critically needed. In the current research, we aimed to screen novel diagnostic biomarkers based on machine learning. The expression profiles were obtained from GEO datasets (GSE20347, GSE38129, and GSE75241) and TCGA datasets. Differentially expressed genes (DEGs) were screened between 47 ESCC and 47 nontumor samples. The LASSO regression model and SVM-RFE analysis were carried out for the identification of potential markers. ROC analysis was carried out to assess discriminatory abilities. The expressions and diagnostic values of the candidates in ESCC were demonstrated in the GSE75241 datasets and TCGA datasets. We also explore the correlations between the critical genes and cancer immune infiltrates using CIBERSORT. In this study, we identified 27 DEGs in ESCC: 5 genes were significantly elevated, and 22 genes were significantly decreased. Based on the results of the SVM-RFE and LASSO regression model, we identified five potential diagnostic biomarkers for ESCC, including GPX3, COL11A1, EREG, MMP1, and MMP12. However, the diagnostic values of only GPX3, MMP1, and MMP12 were confirmed in GSE75241 datasets. Moreover, in TCGA datasets, we further confirmed that GPX3 expression was distinctly decreased in ESCC specimens, while the expression of MMP1 and MMP12 was noticeably increased in ESCC specimens. Immune cell infiltration analysis revealed that the expression of GPX3, MMP1, and MMP12 was associated with several immune, such as T cells CD8, macrophages M2, macrophages M0, and dendritic cells activated. Overall, our findings suggested GPX3, MMP1, and MMP12 as novel diagnostic marker and correlated with immune infiltrates in ESCC patients.

Proliferation Cycle Transcriptomic Signatures are Strongly associated With Gastric Cancer Patient Survival

Gastric cancer is one of the most heterogeneous tumors with multi-level molecular disturbances. Sustaining proliferative signaling and evading growth suppressors are two important hallmarks that enable the cancer cells to become tumorigenic and ultimately malignant, which enable tumor growth. Discovering and understanding the difference in tumor proliferation cycle phenotypes can be used to better classify tumors, and provide classification schemes for disease diagnosis and treatment options, which are more in line with the requirements of today's precision medicine. We collected 691 eligible samples from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database, combined with transcriptome data, to explore different heterogeneous proliferation cycle phenotypes, and further study the potential genomic changes that may lead to these different phenotypes in this study. Interestingly, two subtypes with different clinical and biological characteristics were identified through cluster analysis of gastric cancer transcriptome data. The repeatability of the classification was confirmed in an independent Gene Expression Omnibus validation cohort, and consistent phenotypes were observed. These two phenotypes showed different clinical outcomes, and tumor mutation burden. This classification helped us to better classify gastric cancer patients and provide targeted treatment based on specific transcriptome data.

Therapeutic Influence on Important Targets Associated with Chronic Inflammation and Oxidative Stress in Cancer Treatment

Chronic inflammation and oxidative stress are the interconnected pathological processes, which lead to cancer initiation and progression. The growing level of oxidative and inflammatory damage was shown to increase cancer severity and contribute to tumor spread. The overproduction of reactive oxygen species (ROS), which is associated with the reduced capacity of the endogenous cell defense mechanisms and/or metabolic imbalance, is the main contributor to oxidative stress. An abnormal level of ROS was defined as a predisposing factor for the cell transformation that could trigger pro-oncogenic signaling pathways, induce changes in gene expression, and facilitate accumulation of mutations, DNA damage, and genomic instability. Additionally, the activation of transcription factors caused by a prolonged oxidative stress, including NF-κB, p53, HIF1α, etc., leads to the expression of several genes responsible for inflammation. The resulting hyperactivation of inflammatory mediators, including TNFα, TGF-β, interleukins, and prostaglandins can contribute to the development of neoplasia. Pro-inflammatory cytokines were shown to trigger adaptive reactions and the acquisition of resistance by tumor cells to apoptosis, while promoting proliferation, invasion, and angiogenesis. Moreover, the chronic inflammatory response leads to the excessive production of free radicals, which further aggravate the initiated reactions. This review summarizes the recent data and progress in the discovery of mechanisms that associate oxidative stress and chronic inflammation with cancer onset and metastasis. In addition, the review provides insights for the development of therapeutic approaches and the discovery of natural substances that will be able to simultaneously inhibit several key oncological and inflammation-related targets.

Therapeutic Potential of Selenium and Selenium Compounds in Cervical Cancer

Cervical cancer is a common female cancer. It is strongly associated with human papillomavirus (HPV) infection. However, HPV infection alone is not sufficient to induce cervical cancer because its development is dependent on the coexistence of several factors that enable the virus to overcome the host immune system. These include individual genetic background, environmental factors, or diet, including dietary selenium intake. Selenium is an essential trace element with antiviral properties and has been shown to exert antitumor effects. Surprisingly, the role of selenium in cervical cancer has not been studied as intensively as in other cancers. Here, we have summarized the existing experimental data on selenium and cervical cancer. It may be helpful in evaluating the role of this nutrient in treatment of the mentioned malignancy as well as in planning further studies in this area.

Reduced Expression of GPX3 in Breast Cancer Patients in Correlation with Clinical Significance

Glutathione peroxidase 3 (GPX3) is the main antioxidant enzyme in plasma. Its biological roles are to protect cells from oxidative stress-induced damage. Several studies have been reported the association between GPX3 expression and its correlation with cancer carcinogenesis including breast cancer. The aim of this research was to investigate the GPX3 messenger ribonucleic acid (mRNA) expression in 82 breast tumors and paired normal breast tissues by SYBR green quantitative real-time reverse transcription-polymerase chain reaction and the association with clinicopathological data. Our results show that GPX3 reduced expression was found significantly associated with number of metastatic lymph nodes (odds ratio [OR] = 3.41, 95% confidence interval [CI] = 1.35–8.64, p  = 0.01), no distant metastasis (OR = 5.52, 95% CI = 3.74–11.89, p  = 0.04), and nonhormone usage breast cancer patients (OR = 0.19, 95% CI = 0.04–0.93, p  = 0.04). This finding suggested that GPX3 plays a role in breast carcinogenesis, and might serve as a prognostic biomarker in breast cancer patients.

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.

Glutathione Peroxidase 3 as a Biomarker of Recurrence after Lung Cancer Surgery

We aimed to examine the usefulness of serum glutathione peroxidase 3 (GPx3) as a biomarker of lung cancer recurrence after complete resection. We prospectively collected serial serum samples at the baseline, as well as 3, 6 and 12 months after surgery from complete resection cases in 2013. GPx3 levels were measured by enzyme-linked immunosorbent assay. Statistical tests including t-tests and Cox proportional hazard regression analyses were performed. Totally, 135 patients were enrolled, and 39 (28.9%) showed relapse during the median follow-up period (63.60 months; range, 0.167–81.867). The mean GPx3 change was significantly higher in the recurrence group at 6 months (0.32 ± 0.38 vs. 0.15 ± 0.29, p = 0.016) and 12 months (0.40 ± 0.37 vs. 0.13 ± 0.28, p = 0.001). The high GPx3 change group showed significantly higher 60-months recurrence rates than the low group (48.1% vs. 25.2% at 3 months, p = 0.005; 54.5% vs. 28.9% at 6 months, p = 0.018; 38.3% vs. 18.3% at 12 months, p = 0.035). High GPx3 change at 3 months were independent risk factors of recurrence (hazard ratio (HR) 3.318, 95% confidence interval (CI), 1.582–6.960, p = 0.002) and survival (HR 3.150, 95% CI, 1.301–7.628, p = 0.011). Therefore, serum GPx3 changes after surgery may be useful predictive biomarkers for recurrence in lung cancer. Larger-scale validation studies are warranted to confirm these findings.

The Universal Soldier: Enzymatic and Non-Enzymatic Antioxidant Functions of Serum Albumin

As a carrier of many biologically active compounds, blood is exposed to oxidants to a greater extent than the intracellular environment. Serum albumin plays a key role in antioxidant defence under both normal and oxidative stress conditions. This review evaluates data published in the literature and from our own research on the mechanisms of the enzymatic and non-enzymatic activities of albumin that determine its participation in redox modulation of plasma and intercellular fluid. For the first time, the results of numerous clinical, biochemical, spectroscopic and computational experiments devoted to the study of allosteric modulation of the functional properties of the protein associated with its participation in antioxidant defence are analysed. It has been concluded that it is fundamentally possible to regulate the antioxidant properties of albumin with various ligands, and the binding and/or enzymatic features of the protein by changing its redox status. The perspectives for using the antioxidant properties of albumin in practice are discussed.

Extracellular Glutathione Peroxidase GPx3 and Its Role in Cancer

Mammalian cells possess a multifaceted antioxidant enzyme system, which includes superoxide dismutases, catalase, the peroxiredoxin/thioredoxin and the glutathione peroxidase systems. The dichotomous role of reactive oxygen species and antioxidant enzymes in tumorigenesis and cancer progression complicates the use of small molecule antioxidants, pro-oxidants, and targeting of antioxidant enzymes as therapeutic approaches for cancer treatment. It also highlights the need for additional studies to investigate the role and regulation of these antioxidant enzymes in cancer. The focus of this review is on glutathione peroxidase 3 (GPx3), a selenoprotein, and the only extracellular GPx of a family of oxidoreductases that catalyze the detoxification of hydro- and soluble lipid hydroperoxides by reduced glutathione. In addition to summarizing the biochemical function, regulation, and disease associations of GPx3, we specifically discuss the role and regulation of systemic and tumor cell expressed GPx3 in cancer. From this it is evident that GPx3 has a dichotomous role in different tumor types, acting as both a tumor suppressor and pro-survival protein. Further studies are needed to examine how loss or gain of GPx3 specifically affects oxidant scavenging and redox signaling in the extracellular tumor microenvironment, and how GPx3 might be targeted for therapeutic intervention.

Control of tumor angiogenesis and metastasis through modulation of cell redox state

Redox reactions pervade all biology. The control of cellular redox state is essential for bioenergetics and for the proper functioning of many biological functions. This review traces a timeline of findings regarding the connections between redox and cancer. There is ample evidence of the involvement of cellular redox state on the different hallmarks of cancer. Evidence of the control of tumor angiogenesis and metastasis through modulation of cell redox state is reviewed and highlighted.

Clinical significance of expression of glutathione peroxidase 3 in gastric cancer

BACKGROUND

Glutathione peroxidase 3 (GPX3) expression is down-regulated in gastric cancer (GC), but the relationship between GPX3 expression and prognosis in this malignancy is yet unknown.

AIM

To explore the expression pattern and prognostic value of GPX3 in GC.

METHODS

GPX3 expression was analyzed based on the Oncomine database. The prognostic value of GPX3 in GC patients was investigated using the KM Plotter database. To validate the expression pattern and prognostic value of GPX3, TCGA GC dataset was also analyzed. Finally, the expression pattern and prognostic value of GPX3 was evaluated by tissue microarray and immunohistochemistry in 90 GC patients.

RESULTS

Oncomine database analysis showed that GPX3 was significantly down-regulated in GC tissues compared with normal tissues (P < 0.05). Data from the KM Plotter database showed that GPX3 low expression was significantly related with overall survival (P < 0.05). TCGA dataset analysis also showed that GPX3 low expression was an indicator of better prognosis (P < 0.05). Tissue microarray and immunohistochemistry showed that GPX3 was significantly down-regulated in GC tissue (P = 0.037). GPX3 expression was related with GC patient overall survival (HR = 0.48, 95%CI: 0.28-0.85, P = 0.019), rather than age, gender, and tumor clinical stage.

CONCLUSION

GPX3 is downregulated in GC, and GPX3 expression can be used to predict GC patients' prognosis.

GPX2 suppression of H2O2 stress regulates cervical cancer metastasis and apoptosis via activation of the β-catenin-WNT pathway

BACKGROUND

Increasing evidence suggests that glutathione peroxidase 2 (GPX2) plays important roles in the tumorigenesis and progression of various human cancers, such as colorectal carcinomas and lung adenocarcinomas. However, the role of GPX2 in cervical cancer is unclear. In this study, we identified the role of GPX2 in cervical cancer tissues and cell lines.

MATERIALS AND METHODS

The basal mRNA and protein expression of GPX2 in cervical cancer cells and a series of key molecules in the epithelial to mesenchymal transition (EMT) and WNT/β-catenin pathways were examined via real time fluorescence quantitative PCR (qRT-PCR) and Western blot assays. The biological phenotype of the cervical cancer cell lines was detected by the cloning formation and transwell assays, and intracellular reactive oxygen species (ROS) levels were detected by flow cytometry. Finally, the GPX2 expression level in 100 clinical cervical tissues was examined by immunohistochemistry.

RESULTS

We found that GPX2 was highly expressed in cervical cancer tissues compared to normal individuals and promoted the proliferation and metastasis of cervical cancer cells, and this promotion correlated with the activation of EMT and WNT/β-catenin signaling in vitro. GPX2 was determined to reduce apoptotic damage by reducing hydroperoxides. According to the characteristics and verification of GPX2, this series of phenotypes is clearly related to oxidative stress in cells. Furthermore, we verified that GPX2 was highly expressed in cervical cancer tissues and promoted the metastasis of cervical cancer.

CONCLUSION

In summary, we found that GPX2 was highly expressed in cervical cancer cells and promoted the proliferation and metastasis of cervical cancer by affecting oxidative stress. Our study provides a new target for the clinical treatment of cervical cancer.

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

Glutathione peroxidase 3 (GPX3) has an important function of scavenging hydrogen peroxide and preventing cancer. The purpose of this meta-analysis was to analyze the relationship between GPX3 gene methylation and cancer and to further evaluate its diagnostic value for cancer. We screened eligible literatures from the PubMed, Embase, CNKI and Wanfang databases. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to measure the association of GPX3 methylation with cancer. Summary receiver operating characteristics (SROC) analysis was used to assess the diagnostic value of GPX3 methylation for cancer. A total of 17 eligible articles were included in the meta-analysis involving a total of 960 tumor samples and 445 non-tumor samples. The results showed that GPX3 hypermethylation was significantly associated with cancer (OR = 17.32, 95% CI = 8.22-36.51, P <  0.00001). Compared with cancer patients without lymph node metastasis, cancer patients with lymph node metastasis were more associated with GPX3 hypermethylation (OR = 2.97, 95% CI = 1.53-5.76, P =  0.001). SROC analysis showed for GPX3 methylation was a promising biomarker for cancer risk (AUC = 0.89, pooled sensitivity = 0.93, pooled specificity = 0.54, NLR = 0.15, PLR = 2.05, DOR = 17.32). TCGA database bioinformatics analysis of 696 pairs of tumor and non-tumor tissues further validate the association of GPX3 methylation with the risk of cancer [cg21504918: 0.10 (0.08, 0.15) vs. 0.09 (0.08, 0.11), P = 5.8E-28; cg26638444: 0.05 (0.04, 011) vs. 0.04 (0.03, 0.06), P = 8.7E-29]. In summary, our study indicates that GPX3 methylation is associated with cancer and has the potential to become a broad-spectrum tumor screening marker and has a value in predicting tumor lymph node metastasis.

GPX3 hypermethylation in gastric cancer and its prognostic value in patients aged over 60

AIM

This study investigated the association between GPX3 methylation and gastric cancer (GC), and explored its prognostic value in patients undergoing radical gastrectomy.

MATERIALS & METHODS

The methylation levels of tumor and paracancerous tissues were detected by quantitative methylation-specific PCR method.

RESULTS

GPX3 was hypermethylated in GC (p = 4E-4), and was specific for patients with lymphatic metastasis (+), tumor invasion depth >3 cm and patients with poor differentiation. Additionally, GPX3 hypermethylation predicts a tumor recurrence in patients aged >60 (p = 0.019). Data from The Cancer Genome Atlas (TCGA) further confirmed GPX3 hypermethylation (cg21504918: -0.08 vs -0.25, p = 0.001). Additionally, TCGA showed an inverse correlation between GPX3 methylation and expression (p = 7E-18, r = -0.427). Data analysis of Gene Expression Omnibus (GEO) database showed that 5-aza-2'-deoxycytidine demethylating agent increased GPX3 expression (fold-change >2.19, p = 0.001).

CONCLUSION

Our results indicated GPX3 hypermethylation in GC, and predicted a shorter tumor recurrence time in patients aged >60.

The study of GPX3 methylation in patients with Kashin-Beck Disease and its mechanism in chondrocyte apoptosis

OBJECTIVE

Selenium deficiency is a risk factor for Kashin-Beck Disease (KBD), an endemic osteoarthropathy. Although promoter hypermethylation of glutathione peroxidase 3 (GPX3) (a selenoprotein) has been identified in several cancers, little is known about promoter methylation and expression of GPX3 and their relation to selenium in KBD. The present study was thus conducted to investigate this research question.

METHODS

Methylation and expressions of GPX3 in whole blood drawn from 288 KBD patients and 362 healthy controls and in chondrocyte cell line were evaluated using methylation-specific PCR and qRT-PCR, respectively. The protein levels of PI3K/Akt/c-fos signaling in the whole blood and chondrocyte cell line were determined with Western blotting. Chondrocytes apoptosis were detected by Hoechst 33342 and Annexin V-FITC/PI staining.

RESULTS

GPX3 methylation was increased, GPX3 mRNA was decreased, and protein levels in the PI3K/Akt/c-fos signaling pathway were up-regulated in the whole blood collected from KBD patients as compared with healthy controls. Similar results were obtained for chondrocytes injured by oxidative stress. There was a significant, decreasing trend in GPX3 expression across groups of unmethylation, partial methylation, and complete methylation for GPX3, in sequence. Compared with unmethylation group, protein levels in PI3K/Akt/c-fos pathway were enhanced in partial and complete methylation groups. Treatment of chondrocytes with sodium selenite resulted in reduced methylation and increased expression of GPX3 as well as down-regulated level of PI3K/Akt/c-fos proteins.

CONCLUSIONS

The methylation and expression of GPX3 and expression of PI3K/Akt/c-fos pathway are altered in KBD and these changes are reversible by selenium supplementation.

GPx3 supports ovarian cancer progression by manipulating the extracellular redox environment

Ovarian cancer remains the most lethal gynecologic malignancy, and is primarily diagnosed at late stage when considerable metastasis has occurred in the peritoneal cavity. At late stage abdominal cavity ascites accumulation provides a tumor-supporting medium in which cancer cells gain access to growth factors and cytokines that promote survival and metastasis. However, little is known about the redox status of ascites, or whether antioxidant enzymes are required to support ovarian cancer survival during transcoelomic metastasis in this medium. Gene expression cluster analysis of antioxidant enzymes identified two distinct populations of high-grade serous adenocarcinomas (HGSA), the most common ovarian cancer subtype, which specifically separated into clusters based on glutathione peroxidase 3 (GPx3) expression. High GPx3 expression was associated with poorer overall patient survival and increased tumor stage. GPx3 is an extracellular glutathione peroxidase with reported dichotomous roles in cancer. To further examine a potential pro-tumorigenic role of GPx3 in HGSA, stable OVCAR3 GPx3 knock-down cell lines were generated using lentiviral shRNA constructs. Decreased GPx3 expression inhibited clonogenicity and anchorage-independent cell survival. Moreover, GPx3 was necessary for protecting cells from exogenous oxidant insult, as demonstrated by treatment with high dose ascorbate. This cytoprotective effect was shown to be due to GPx3-dependent removal of extracellular H₂O₂. Importantly, GPx3 was necessary for clonogenic survival when cells were cultured in patient-derived ascites fluid. While oxidation reduction potential (ORP) of malignant ascites was heterogeneous in our patient cohort, and correlated positively with ascites iron content, GPx3 was required for optimal survival regardless of ORP or iron content. Collectively, our data suggest that HGSA ovarian cancers cluster into distinct groups of high and low GPx3 expression. GPx3 is necessary for HGSA ovarian cancer cellular survival in the ascites tumor environment and protects against extracellular sources of oxidative stress, implicating GPx3 as an important adaptation for transcoelomic metastasis.

•

High grade serous ovarian cancers cluster into distinct groups of antioxidant enzyme expression.

•

High GPx3 expression is associated with decreased overall patient survival.

•

GPx3 promotes cell viability by protecting cells from extracellular sources of oxidative stress.

•

GPx3 enhances cell survival in ovarian cancer patient ascites fluid.

•

Malignant ascites oxidation-reduction potential correlates with iron content.

Distinct prognostic values of mRNA expression of glutathione peroxidases in non-small cell lung cancer

Introduction

Glutathione peroxidases (GPxs) constitutes an enzyme family which has the ability to reduce free hydrogen peroxide to water and lipid hydroperoxides to their corresponding alcohols, and its main biological roles are to protect organisms from oxidative stress-induced damage. GPxs include eight members in different tissues of the body, and they play essential roles in carcinogenesis. However, the prognostic value of individual GPx in non-small cell lung cancer (NSCLC) remains elusive.

Materials and methods

In the current study, we investigated the prognostic value of GPxs in NSCLC patients through the “Kaplan–Meier plotter” database, wherein updated gene expression data and survival information from a total of 1,926 NSCLC patients are included.

Results

High expression of GPx1 mRNA was correlated with worse overall survival (OS) in adenocarcinoma patients. High expression of GPx2 mRNA was correlated with worse OS for all NSCLC patients. In contrast, high expression of GPx3 mRNA was associated with better OS for all NSCLC patients. High expression of GPx4 mRNA was significantly correlated with worsening adenocarcinoma in these patients. GPx5 mRNA high expression correlated with worsening OS for all NSCLC patients.

Discussion

The current findings of prognostic values of individual mRNA expression of GPxs in NSCLC patients indicate some GPxs may have prognostic value in NSCLC patients, and this needs further study.

The Progress of Methylation Regulation in Gene Expression of Cervical Cancer

Cervical cancer is one of the most common gynecological tumors in females, which is closely related to high-rate HPV infection. Methylation alteration is a type of epigenetic decoration that regulates the expression of genes without changing the DNA sequence, and it is essential for the progression of cervical cancer in pathogenesis while reflecting the prognosis and therapeutic sensitivity in clinical practice. Hydroxymethylation has been discovered in recent years, thus making 5-hmC, the more stable marker, attract more attention in the field of methylation research. As markers of methylation, 5-hmC and 5-mC together with 5-foC and 5-caC draw the outline of the reversible cycle, and 6-mA takes part in the methylation of RNA, especially mRNA. Furthermore, methylation modification participates in ncRNA regulation and histone decoration. In this review, we focus on recent advances in the understanding of methylation regulation in the process of cervical cancer, as well as HPV and CIN, to identify the significant impact on the prospect of overcoming cervical cancer.

Comparative genomics reveals that loss of lunatic fringe (LFNG) promotes melanoma metastasis

Metastasis is the leading cause of death in patients with advanced melanoma, yet the somatic alterations that aid tumour cell dissemination and colonisation are poorly understood. Here, we deploy comparative genomics to identify and validate clinically relevant drivers of melanoma metastasis. To do this, we identified a set of 976 genes whose expression level was associated with a poor outcome in patients from two large melanoma cohorts. Next, we characterised the genomes and transcriptomes of mouse melanoma cell lines defined as weakly metastatic, and their highly metastatic derivatives. By comparing expression data between species, we identified lunatic fringe (LFNG), among 28 genes whose expression level is predictive of poor prognosis and whose altered expression is associated with a prometastatic phenotype in mouse melanoma cells. CRISPR/Cas9-mediated knockout of Lfng dramatically enhanced the capability of weakly metastatic melanoma cells to metastasise in vivo, a phenotype that could be rescued with the Lfng cDNA. Notably, genomic alterations disrupting LFNG are found exclusively in human metastatic melanomas sequenced as part of The Cancer Genome Atlas. Using comparative genomics, we show that LFNG expression plays a functional role in regulating melanoma metastasis.

Selenium and Epigenetics in Cancer: Focus on DNA Methylation

Chemopreventive activity of selenium (Se) may influence epigenome. In this review, we have discussed two aspects of Se and epigenetics in cancer, related to (1) the association between Se and epigenetic regulation in cancer development and prevention; (2) epigenetic modification of selenoprotein-encoding genes in different cancers. In both issues, we focused on DNA methylation as the most investigated epigenetic mechanism. The existing evidence from experimental data in human cancer cell lines, rodents, and human studies in cancer-free subjects indicates that: high Se exposure leads to the inhibition of DNA methyltransferase expression/activity; the association between Se and global methylation remains unclear and requires further investigation with respect to the underlying mechanisms and possible nonlinear character of this relationship; Se affects methylation of specific tumor suppressor genes, possibly in a sex-dependent manner; and cancer phenotype is often characterized by altered methylation of selenoprotein-encoding genes, mainly glutathione peroxidase 3.

Glutathione peroxidases as oncotargets

Oxidative stress is a disturbance in the equilibrium among free radicals, reactive oxygen species, and endogenous antioxidant defense mechanisms. Oxidative stress is a result of imbalance between the production of reactive oxygen and the biological system's ability to detoxify the reactive intermediates or to repair the resulting damage. Mounting evidence has implicated oxidative stress in various physiological and pathological processes, including DNA damage, proliferation, cell adhesion, and survival of cancer cells. Glutathione peroxidases (GPxs) (EC 1.11.1.9) are an enzyme family with peroxidase activity whose main biological roles are to protect organisms from oxidative damage by reducing lipid hydroperoxides as well as free hydrogen peroxide. Currently, 8 sub-members of GPxs have been identified in humans, all capable of reducing H₂O₂ and soluble fatty acid hydroperoxides. A large number of publications has demonstrated that GPxs have significant roles in different stages of carcinogenesis. In this review, we will update recent progress in the study of the roles of GPxs in cancer. Better mechanistic understanding of GPxs will potentially contribute to the development and advancement of improved cancer treatment models.

Contribution of mammalian selenocysteine-containing proteins to carcinogenesis

Oxidative stress caused by a sharp growth of free radicals in the organism is a major cause underlying the occurrence of all kinds of malignant formations. Selenium is an important essential trace element found in selenoproteins in the form of selenocysteine, an amino acid differing from cysteine for the presence of selenium instead of sulfur and making such proteins highly active. To date the role of selenium has been extensively investigated through studying the functions of selenoproteins in carcinogenesis. Analysis of the obtained results clearly demonstrates that selenoproteins can act as oncosuppressors, but can also, on the contrary, favor the formation of malignant tumors.

GPX3 methylation in bone marrow predicts adverse prognosis and leukemia transformation in myelodysplastic syndrome

Epigenetic inactivation of GPX3 has been identified in various cancers including leukemia. Moreover, aberrant DNA methylation was also found as a dominant mechanism of disease progression in myelodysplastic syndrome (MDS). This study intended to explore GPX3 promoter methylation and its clinical relevance in 110 patients with MDS. GPX3 methylation was examined by real-time quantitative methylation-specific PCR (RQ-MSP) and bisulfite sequencing PCR (BSP). GPX3 methylation was identified in 15% (17/110) MDS patients, and significantly higher than controls, and lower than acute myeloid leukemia (AML) patients (P = 0.024 and 0.041). GPX3 methylated patients had older age and higher frequency of DNMT3A mutation (P = 0.015 and 0.066). Cases with GPX3 methylation showed significantly shorter overall survival (OS) time than those with GPX3 unmethylation analyzed with Kaplan-Meier analysis (P = 0.012). Moreover, Cox regression analysis revealed that GPX3 methylation might act as an independent prognostic indicator in MDS (HR = 1.847, P = 0.072). GPX3 methylation density was significantly increased during the progression from MDS to secondary acute myeloid leukemia (sAML) in three follow-up paired patients. Our study concludes that GPX3 methylation in bone marrow is associated with adverse prognosis and leukemia transformation in MDS.

CPE overexpression is correlated with pelvic lymph node metastasis and poor prognosis in patients with early-stage cervical cancer

PURPOSE

Elevated carboxypeptidase E (CPE) levels play crucial roles in tumorigenesis and metastasis. This study investigated the expression and clinicopathological significance of CPE in early-stage cervical cancer.

METHODS

Elevated carboxypeptidase E expression was analyzed using quantitative polymerase chain reaction and western blotting in normal cervical tissue, cervical cancer cell lines, and in cervical cancer tissues and adjacent noncancerous tissues (ANTs) from the same patient. Immunohistochemistry (IHC) was used to examine CPE expression in tissue samples from 112 patients with early-stage cervical cancer (FIGO stages Ia2-IIa2), 60 patients with cervical intraepithelial neoplasia, and 19 patients with normal cervical tissues (NCTs). Associations between CPE expression and prognostic and diagnostic factors were evaluated statistically.

RESULTS

CPE expression was significantly higher in cervical cancer cell lines and tissues than in normal tissues and ANTs. Semi-quantitative analysis of IHC indicated that CPE gradually increased from CIN I to cervical cancer, but was absent in NCTs. CPE expression was seen in 40.2 % (45/112) of the cervical cancer samples. CPE expression was significantly associated with FIGO stage (P = 0.003), tumor size (P = 0.012), stromal invasion (P < 0.001), lymphovascular space invasion (P = 0.016), parametrial infiltration (P = 0.027), vaginal involvement (P = 0.007), postoperative adjuvant therapy (P = 0.024), recurrence (P < 0.001), survival (P < 0.001), and pelvic lymph node metastasis (PLNM) (P < 0.001), and it was significantly higher in tissues from patients with PLNM than without PLNM. Logistic regression analysis identified high-level CPE expression as an independent risk factor for PLNM (P = 0.001). Patients with higher CPE expression had shorter overall survival duration than patients with lower CPE expression. Univariate and multivariate Cox-regression analyses suggested that high-level CPE expression is an independent prognostic factor for overall survival in early-stage cervical cancer.

CONCLUSIONS

High-level CPE expression was associated with a poor prognosis in early-stage cervical cancer. CPE may serve as a biomarker for predicting PLNM and survival in these patients.

[On the Enzymatic Activity of Albumin]

Albumin molecule, unlike molecules of many other plasma proteins, is not covered with carbohydrate shell. It plays a crucial role in maintaining of colloid osmotic pressure of the blood, and is able to bind and transport various endogenous and exogenous molecules. The enzymatic activity of albumin, the existence and the role of which most researchers are still skeptical to accept, is of the main interest to us. In this review, a history of the issue is traced, with particular attention to the esterase activity of albumin. The kinetic and thermodynamic characteristics of the interaction of albumin with some substrates are adduced, and possibility of albumin being attributed to certain groups of Enzyme Nomenclature is considered.

Assessment of the Selenoprotein M (SELM) over-expression on human hepatocellular carcinoma tissues by immunohistochemistry

Selenium is an essential trace mineral of fundamental importance to human healthy and exerts its biological function through selenoproteins. In particular, Selenoprotein M (SELM) is located in the endoplasmic reticulum and contains the common redox motif of cysteine-X-X-selenocysteine type. It attracts great attention due to its high expression in brain and its potential roles as antioxidant, neuroprotective, and cytosolic calcium regulator. Recently, our group found SELM over-expression in human hepatocellular carcinoma (HCC) cell lines. In this report some paraffin-embedded tissues from liver biopsy of patients with hepatitis C virus (HCV)-related cirrhosis and HCC were immunohistochemically stained and SELM expression scoring was evaluated. Our results evidence for the first time an increase of SELM expression in HCC liver tissues, and its gradual expression raise associated with an increased malignancy grade. Therefore, we propose to use i) SELM as putative marker for HCC as well as ii) simple immunohistochemistry technique to distinguish between the different grades of malignancy.