Expression of metallothionein-1 and metallothionein-2 as a prognostic marker in hepatocellular carcinoma

Suppression of pseudogene MT2P1 transcription induced by E2F7 inhibits hepatocellular carcinoma cell proliferation and facilitates apoptosis via preserving its parental gene

The majority of the pseudogenes are inert in normal transcription. Their transcripts are mostly attributed to non-coding RNAs that play various functions in human tumorigenicity and progression. Distinctively, pseudogene MT2P1 is universally transcribed in hepatocytes and presents a significant decrease in hepatocellular carcinoma (HCC). The effect of MT2P1-RNA on HCC cell proliferation and apoptosis needs investigation. MT2P1-RNA was detected by RT-qPCR assay in HCC tissues and cell lines, combined with the exploration of the public databases. The immunohistochemistry assay was used for testing the expression profile of E2F7 and the parental gene MT2A. The clinicopathological features of the patients were collected and analyzed. Ectopic expression of MT2P1-RNA in HCC cell lines was conducted, and the CCK8 assay and flow cytometry assay were carried out. Chromatin immunoprecipitation assay and Dual-luciferase reporter assay were, respectively, applied to validate the interaction between MT2P1, E2F7, and microRNA-15b-5p. The downregulation of MT2P1-RNA in HCC is negatively correlated with dismal clinicopathological features. MT2P1-RNA significantly suppressed HCC cell proliferation and induced apoptosis. E2F7 depletion sequentially elevated the level of MT2P1-RNA and MT2A, and E2F7 was validated as a suppressive transcription factor of the MT2P1 gene. The direct interactions of either MT2P1/miR-15b-5p or miR-15b-5p/MT2A were, respectively, ascertained, enlightening the ceRNA effect of them. The pseudogene-derived MT2P1-RNA is a suppressor of HCC by exerting the ceRNA effect on preserving MT2A, and its transcription is regulated by the suppressive transcription factor E2F7.

Integrated transcriptomics and proteomics analysis of the impact of iodine‑125 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common cause of cancer‑related mortality and morbidity worldwide. While iodine‑125 (125I) particle brachytherapy has been extensively used in the clinical treatment of various types of cancer, the precise mechanism underlying its effectiveness in treating HCC remains unclear. In the present study, MHCC‑97H cells were treated with 125I, after which, cell viability and proliferation were assessed using Cell Counting Kit‑8, 5‑ethynyl‑2'‑deoxyuridine and colony formation assays, cell invasion and migration were evaluated using wound healing and Transwell assays, and cell apoptosis was determined using flow cytometry. Omics data were analyzed using Kyoto Encyclopedia of Genes and Genomes, Gene Ontology and STRING analyses to observe the key genes that exhibited significant changes at the transcriptional and protein levels in MHCC‑97H cells treated with 125I particles. Finally, the expression levels of key genes (GPNMB, C4BPA, CTH, H1‑0 and MT2A) were verified through reverse transcription quantitative PCR. Following treatment with 125I, the proliferation, invasion and migration of MHCC‑97H cells were inhibited, and apoptosis was enhanced. The results of omics data analysis indicated that the biological behavior of MHCC‑97H cells treated with 125I was related to the expression levels of CTH and MT2A genes. These findings indicated that intervention with 125I radiation particles may induce changes in gene expression, potentially influencing alterations in biological characteristics. In conclusion, these insights may shed light on the underlying mechanisms of 125I radiation particle therapy in HCC and offer novel targets for HCC treatment.

The association between trace metals in both cancerous and non-cancerous tissues with the risk of liver and gastric cancer progression in northwest China

Liver cancer and gastric cancer have extremely high morbidity and mortality rates worldwide. It is well known that an increase or decrease in trace metals may be associated with the formation and development of a variety of diseases, including cancer. Therefore, this study aimed to evaluate the contents of aluminium (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), selenium (Se), and zinc (Zn) in cancerous liver and gastric tissues, compared to adjacent healthy tissues, and to investigate the relationship between trace metals and cancer progression. During surgery, multiple samples were taken from the cancerous and adjacent healthy tissues of patients with liver and gastric cancer, and trace metal levels within these samples were analysed using inductively coupled plasma mass spectrometry (ICP-MS). We found that concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn in tissues from patients with liver cancer were significantly lower than those in healthy controls (P < 0.05). Similarly, patients with gastric cancer also showed lower levels of Cd, Co, Cr, Mn, Ni, and Zn-but higher levels of Cu and Se-compared to the controls (P < 0.05). In addition, patients with liver and gastric cancers who had poorly differentiated tumours and positive lymph node metastases showed lower levels of trace metals (P < 0.05), although no significant changes in their concentrations were observed to correlate with sex, age, or body mass index (BMI). Logistic regression, principal component analysis (PCA), Bayesian kernel regression (BKMR), weighted quantile sum (WQS) regression, and quantile-based g computing (qgcomp) models were used to analyse the relationships between trace metal concentrations in liver and gastric cancer tissues and the progression of these cancers. We found that single or mixed trace metal levels were negatively associated with poor differentiation and lymph node metastasis in both liver and gastric cancer, and the posterior inclusion probability (PIP) of each metal showed that Cd contributed the most to poor differentiation and lymph node metastasis in both liver and gastric cancer (all PIP = 1.000). These data help to clarify the relationship between changes in trace metal levels in cancerous liver and gastric tissues and the progression of these cancers. Further research is warranted, however, to fully elucidate the mechanisms and causations underlying these findings.

Schistosoma mansoni infection induces hepatic metallothionein and S100 protein expression alongside metabolic dysfunction in hamsters

Schistosomiasis, a widespread neglected tropical disease, presents a complex and multifaceted clinical-pathological profile. Using hamsters as final hosts, we dissected molecular events following Schistosoma mansoni infection in the liver-the organ most severely affected in schistosomiasis patients. Employing tandem mass tag-based proteomics, we studied alterations in the liver proteins in response to various infection modes and genders. We examined livers from female and male hamsters that were: noninfected (control), infected with either unisexual S. mansoni cercariae (single-sex) or both sexes (bisex). The infection induced up-regulation of proteins associated with immune response, cytoskeletal reorganization, and apoptotic signaling. Notably, S. mansoni egg deposition led to the down-regulation of liver factors linked to energy supply and metabolic processes. Gender-specific responses were observed, with male hamsters showing higher susceptibility, supported by more differentially expressed proteins than found in females. Of note, metallothionein-2 and S100a6 proteins exhibited substantial up-regulation in livers of both genders, suggesting their pivotal roles in the liver's injury response. Immunohistochemistry and real-time-qPCR confirmed strong up-regulation of metallothionein-2 expression in the cytoplasm and nucleus upon the infection. Similar findings were seen for S100a6, which localized around granulomas and portal tracts. We also observed perturbations in metabolic pathways, including down-regulation of enzymes involved in xenobiotic biotransformation, cellular energy metabolism, and lipid modulation. Furthermore, lipidomic analyses through liquid chromatography-tandem mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry imaging identified extensive alterations, notably in cardiolipin and triacylglycerols, suggesting specific roles of lipids during pathogenesis. These findings provide unprecedented insights into the hepatic response to S. mansoni infection, shedding light on the complexity of liver pathology in this disease.

CT23 knockdown attenuating malignant behaviors of hepatocellular carcinoma cell is associated with upregulation of metallothionein 1

The cancer-testis antigen 23 (CT23) gene has been reported in association with the pathogenesis and progress of hepatocellular carcinoma (HCC). However, the alterations of gene expression profiling induced by CT23 knockdown in HCC cells remains largely unknown. In this study, the RNA interfering (RNAi) method was used to silence CT23 expression in BEL-7404 cells. Microarray analysis was performed on mRNA extracted from the CT23 knockdown cells and the control cells to determine the alterations of gene expression profiles. The result showed a total of 1051 genes expressed differentially (two-fold change), including 470 genes upregulated and 581 gene downregulated in the CT23 knockdown cells. A bioinformatic analysis showed that the functional differentially expressed genes (DEGs) were linked to cell proliferation, migration, and apoptosis, and metallothionein 1 (MT1) attained the maximum enrichment scores in functional annotation, classification, and pathway analysis of DEGs. Furthermore, Western blot analysis and cell behaviors assays verified that CT23 modulates cell proliferation, migration, and apoptosis by regulating MT1 expression in HCC cells and non-neoplastic hepatocytes. In summary, downregulated CT23 gene in BEL-7404 cells might change the expressions of carcinogenesis and progression related genes in HCC by upregulating MT1 expression, which would provide insight into searching for a novel therapeutic target for HCC.

Integrative Analysis of Metallothioneins Identifies MT1H as Candidate Prognostic Biomarker in Hepatocellular Carcinoma

Background: Metallothioneins (MTs) play crucial roles in the modulation of zinc/copper homeostasis, regulation of neoplastic growth and proliferation, and protection against apoptosis. The present study attempted to visualize the prognostic landscape of MT functional isoforms and identify potential prognostic biomarkers in hepatocellular carcinoma (HCC). Methods: The transcriptional expression, comprehensive prognostic performances, and gene-gene interaction network of MT isoforms in HCC were evaluated via Oncomine, GEPIA, Kaplan-Meier plotter, and GeneMANIA databases. Characterized by good prognostic value in three external cohorts, MT1H was specifically selected as a potential prognostic biomarker in HCC with various clinicopathological features. Functional and pathway enrichment analyses of MT1H status were performed using cBioPortal, the Database for Annotation, Visualization, and Integrated Discovery (DAVID), and ssGSVA method. Results: MT1E/1F/1G/1H/1M/1X/2A was greatly downregulated in HCC. Prognostic analyses elucidated the essential correlations between MT1A/1B/1H/1X/2A/4 attenuation and poor overall survival, between MT1B/1H/4 downregulation and worse relapse-free survival, and between MT1A/1B/1E/1H/1M/2A/4 downregulation and diminished progression-free survival in HCC. Taken together, these results indicated the powerful prognostic value of MT1H among MTs in HCC. In-depth analyses suggested that MT1H may be more applicable to alcohol-derived HCC and involved in the downregulation of the inflammatory pathway, Jak-STAT pathway, TNF pathway, and Wnt signaling pathway. Conclusion: MT-specific isoforms displayed aberrant expression and varying prognostic value in HCC. MT1H repression in HCC was multi-dimensionally detrimental to patient outcomes. Therefore, MT1H was possibly associated with carcinogenesis and exploited as a novel prognostic biomarker and candidate therapeutic target for HCC.

MT1G serves as a tumor suppressor in hepatocellular carcinoma by interacting with p53

Poor prognosis of hepatocellular carcinoma (HCC) patients is frequently associated with rapid tumor growth, recurrence and drug resistance. MT1G is a low-molecular weight protein with high affinity for zinc ions. In the present study, we investigated the expression of MT1G, analyzed clinical significance of MT1G, and we observed the effects of MT1G overexpression on proliferation and apoptosis of HCC cell lines in vitro and in vivo. Our results revealed that MT1G was significantly downregulated in tumor tissues, and could inhibit the proliferation as well as enhance the apoptosis of HCC cells. The mechanism study suggested that MT1G increased the stability of p53 by inhibiting the expression of its ubiquitination factor, MDM2. Furthermore, MT1G also could enhance the transcriptional activity of p53 through direct interacting with p53 and providing appropriate zinc ions to p53. The modulation of MT1G on p53 resulted in upregulation of p21 and Bax, which leads cell cycle arrest and apoptosis, respectively. Our in vivo assay further confirmed that MT1G could suppress HCC tumor growth in nude mice. Overall, this is the first report on the interaction between MT1G and p53, and adequately uncover a new HCC suppressor which might have therapeutic values by diminishing the aggressiveness of HCC cells.

Long-term iron exposure causes widespread molecular alterations associated with memory impairment in mice

Limited literature available indicates the neurotoxic effects of excessive iron, however, a deep understanding of iron neurotoxicity needs to be developed. In this study, we evaluated the toxic effects of excessive iron on learning and cognitive function in long-term iron exposure (oral, 10 mg/L, 6 months) of mice by behavioral tests including novel object recognition test, step-down passive avoidance test and Morris water maze test, and further analyzed differential expression of hippocampal proteins. The behavioral tests consistently showed that iron treatment caused cognitive defects of the mice. Proteomic analysis revealed 66 differentially expressed hippocampal proteins (30 increased and 36 decreased) in iron-treated mice as compared with the control ones. Bioinformatics analysis showed that the dysregulated proteins mainly included: synapse-associated proteins (i.e. synaptosomal-associated protein 25 (SNAP25), complexin-1 (CPLX1), vesicle-associated membrane protein 2 (VAMP2), neurochondrin (NCDN)); mitochondria-related proteins (i.e. ADP/ATP translocase 1 (SLC25A4), 14-3-3 protein zeta/delta (YWHAZ)); cytoskeleton proteins (i.e. neurofilament light polypeptide (NEFL), tubulin beta-2B chain (TUBB2B), tubulin alpha-4A chain (TUBA4A)). The findings suggest that the dysregulations of synaptic, mitochondrial, and cytoskeletal proteins may be involved in iron-triggered memory impairment. This study provides new insights into the molecular mechanisms of iron neurotoxicity.

Metallothioneins may be a potential prognostic biomarker for tumors: A Prisma-compliant meta-analysis

BACKGROUND

Metallothioneins (MTs) were reported to be associated with many kinds of tumors' prognosis, although MTs expression varied greatly among tumors. To assess the prognostic value of Metallothioneins (MTs) in different kinds of tumors, comprehensive literature search was conducted to perform a meta-analysis.

METHODS

Eligible studies were identified by PubMed, MEDLINE, Web of Science (WOS), the Cochrane Library of Systematic Reviews, EMBASE, China National Knowledge Infrastructure (CNKI), WANFANG database and SinoMed database up to December 2017, which was designed to assess the prognostic value of MTs in different kinds of tumors. The main endpoint events were overall survival (OS) and disease-free survival (DFS). Hazard ratios (HRs) and its variance were retrieved from the original studies directly or calculated using Engauge Digitizer version 4.1. Random or fixed effects model meta-analysis was employed depending on the heterogeneity. Publication bias was evaluated by funnel plots, Begg and Egger tests.

RESULTS

A total of 22 studies were enrolled in this meta-analysis, including 2843 tumor tissues (1517 were MTs negative/low, and 1326 were MTs high). Results showed that there was significant association between MTs expression and tumors' OS (HR = 1.60; 95%CI 1.34∼1.92, P < .00001). Subgroup analysis showed that high level of MTs expression was associated with prolonged OS in liver cancer (HR = 0.65, 95%CI 0.48∼0.89, P = .007), but it was on the contrary in the tumor of ovary (HR = 1.47, 95%CI 1.01∼2.14, P = .04), bladder (HR = 1.71, 95%CI 1.21∼2.42, P = .002), intestine (HR = 3.13, 95%CI 1.97∼4.97, P < .00001), kidney (HR = 3.31, 95%CI 1.61∼6.79, P = .001). However, there was no significant association between MTs expression and OS in breast (HR = 1.02, 95%CI 0.69∼1.51, P = .93).

CONCLUSIONS

MTs could be taken as a potential prognostic biomarker for tumors, and uniqueness of MTs prognostic value in liver cancer deserved further study.

The roles of metallothioneins in carcinogenesis

Metallothioneins (MTs) are small cysteine-rich proteins that play important roles in metal homeostasis and protection against heavy metal toxicity, DNA damage, and oxidative stress. In humans, MTs have four main isoforms (MT1, MT2, MT3, and MT4) that are encoded by genes located on chromosome 16q13. MT1 comprises eight known functional (sub)isoforms (MT1A, MT1B, MT1E, MT1F, MT1G, MT1H, MT1M, and MT1X). Emerging evidence shows that MTs play a pivotal role in tumor formation, progression, and drug resistance. However, the expression of MTs is not universal in all human tumors and may depend on the type and differentiation status of tumors, as well as other environmental stimuli or gene mutations. More importantly, the differential expression of particular MT isoforms can be utilized for tumor diagnosis and therapy. This review summarizes the recent knowledge on the functions and mechanisms of MTs in carcinogenesis and describes the differential expression and regulation of MT isoforms in various malignant tumors. The roles of MTs in tumor growth, differentiation, angiogenesis, metastasis, microenvironment remodeling, immune escape, and drug resistance are also discussed. Finally, this review highlights the potential of MTs as biomarkers for cancer diagnosis and prognosis and introduces some current applications of targeting MT isoforms in cancer therapy. The knowledge on the MTs may provide new insights for treating cancer and bring hope for the elimination of cancer.

Effect of cadmium on uptake of iron, zinc and copper and mRNA expression of metallothioneins in HepG2 cells in vitro

The intake of cadmium contaminated fish was mimicked by incubating human hepatoblastoma cells (Cell line HepG2) with a combination of different levels of cadmium (0-5μM) plus the n-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid, which are typical for fish. Uptake of cadmium, iron, copper and zinc was measured by ICP-MS. In addition mRNA expression of two metallothioneins (mt1 g and mt1 m) was evaluated by real-time PCR. The obtained data shows that the presence of cadmium increases the uptake of iron and zinc into the HepG2 cells while the uptake of copper remains unaffected. The presence of the chosen fatty acids did not affect the uptake of either cadmium or iron, zinc and copper. The presence of already 1μM cadmium increased the mRNA expression of mt1 g and mt1 m significantly, while the fatty acids did not interfere with the effect of cadmium.

Gene expression profiling, pathway analysis and subtype classification reveal molecular heterogeneity in hepatocellular carcinoma and suggest subtype specific therapeutic targets

A very low 5-year survival rate among hepatocellular carcinoma (HCC) patients is mainly due to lack of early stage diagnosis, distant metastasis and high risk of postoperative recurrence. Hence ascertaining novel biomarkers for early diagnosis and patient specific therapeutics is crucial and urgent. Here, we have performed a comprehensive analysis of the expression data of 423 HCC patients (373 tumors and 50 controls) downloaded from The Cancer Genome Atlas (TCGA) followed by pathway enrichment by gene ontology annotations, subtype classification and overall survival analysis. The differential gene expression analysis using non-parametric Wilcoxon test revealed a total of 479 up-regulated and 91 down-regulated genes in HCC compared to controls. The list of top differentially expressed genes mainly consists of tumor/cancer associated genes, such as AFP, THBS4, LCN2, GPC3, NUF2, etc. The genes over-expressed in HCC were mainly associated with cell cycle pathways. In total, 59 kinases associated genes were found over-expressed in HCC, including TTK, MELK, BUB1, NEK2, BUB1B, AURKB, PLK1, CDK1, PKMYT1, PBK, etc. Overall four distinct HCC subtypes were predicted using consensus clustering method. Each subtype was unique in terms of gene expression, pathway enrichment and median survival. Conclusively, this study has exposed a number of interesting genes which can be exploited in future as potential markers of HCC, diagnostic as well as prognostic and subtype classification may guide for improved and specific therapy.

Dysregulation of metallothionein and circadian genes in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the major threat to human health, and disruption of circadian clock genes is implicated in hepatocarcinogenesis. This study examined the dysregulation of metallothioneins and circadian genes in achieved human HCC (n = 24), peri-HCC tissues (n = 24) as compared with normal human livers (n = 36). Total RNA was extracted and reverse transcribed. Real-time RT-qPCR was performed to determine the expression of genes of interest. The results demonstrated the downregulation of metallothionein-1 (MT-1), MT-2, and metal transcription factor-1 (MFT-1) in human HCC as compared with Peri-HCC and normal tissues. MTs are a biomarker for HCC and have typical circadian rhythms; the expression of major circadian clock genes was also determined. HCC produced a dramatic decrease in the expression of core clock genes, circadian locomotor output cycles kaput (Clock) and brain and muscle Arnt-like protein 1 (Bmal1), and decreased the expression of the clock feedback control genes, Periods (Per1, Per2) and Cryptochromes (Cry1, Cry2). On the other hand, the expression of clock target genes nuclear orphan receptor factor protein (Nr1d1) and D-box-binding protein (Dbp) was upregulated as compared with Peri-HCC and normal livers. Peri-HCC also had mild alterations in these gene expressions. In summary, the present study clearly demonstrated the dysregulation of MTs and circadian clock genes in human HCC, which could provide the information of targeting MT and circadian clock in HCC management.

Label-free bead-based metallothionein electrochemical immunosensor

A novel microfluidic label-free bead-based metallothionein immunosensors was designed. To the surface of superparamagnetic agarose beads coated with protein A, polyclonal chicken IgY specifically recognizing metallothionein (MT) were immobilized via rabbit IgG. The Brdicka reaction was used for metallothionein detection in a microfluidic printed 3D chip. The assembled chip consisted of a single copper wire coated with a thin layer of amalgam as working electrode. Optimization of MT detection using designed microfluidic chip was performed in stationary system as well as in the flow arrangement at various flow rates (0-1800 μL/min). In stationary arrangement it is possible to detect MT concentrations up to 30 ng/mL level, flow arrangement allows reliable detection of even lower concentration (12.5 ng/mL). The assembled miniature flow chip was subsequently tested for the detection of MT elevated levels (at approx. level 100 μg/mL) in samples of patients with cancer. The stability of constructed device for metallothionein detection in flow arrangement was found to be several days without any maintenance needed.

Metallothioneins and digestive system tumors

Metallothioneins (MTs) are low-molecular weight, cysteine-rich, intracellular metal-binding proteins involved in diverse functions, such as metal homeostasis and/or detoxification, scavenging free radicals and stress response. Recent studies show that MTs play an important role in cell differentiation, proliferation and carcinogenesis by displaying different expression patterns and through different signaling pathways, have important value for the clinical diagnosis, treatment and prognosis of tumors, and can be used as a cancer biomarker. This article aims to discuss the research progress in MTs as a cancer maker in human digestive system tumors.

Novel hepatocellular carcinoma molecules with prognostic and therapeutic potentials

Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, is the sixth most common cancer worldwide and the third leading cause of cancer-related death. The difficulty to diagnose early cancer stages, the aggressive behaviors of HCC, and the poor effectiveness of therapeutic treatments, represent the reasons for the quite similar deaths per year and incidence number. Considering the fact that the diagnosis of HCC typically occurs in the advanced stages of the disease when the therapeutic options have only modest efficacy, the possibility to identify early diagnostic markers could be of significant benefit. So far, a large number of biomarkers have been associated to HCC progression and aggressiveness, but many of them turned out not to be of practical utility. This is the reason why active investigations are ongoing in this field. Given the huge amount of published works aimed at the identification of HCC biomarkers, in this review we mainly focused on the data published in the last year, with particular attention to the role of (1) molecular and biochemical cellular markers; (2) micro-interfering RNAs; (3) epigenetic variations; and (4) tumor stroma. It is worth mentioning that a significant number of the HCC markers described in the present review may be utilized also as targets for novel therapeutic approaches, indicating the tight relation between diagnosis and therapy. In conclusion, we believe that integrated researches among the different lines of investigation indicated above should represent the winning strategies to identify effective HCC markers and therapeutic targets.