metallothionein and Stomach-Neoplasms

Gastric cancer (GC) is a highly prevalent and aggressive malignancy with a poor prognosis. Recent evidence suggested that metallothionein 1 M (MT1M) may play a critical role in cancer development, progression, and drug resistance; however, its role in GC remains largely unknown. In this study, we investigated the expression and function of MT1M in GC both in vitro and in vivo. We found that MT1M expression was significantly downregulated in GC tissues and cell lines. Decreased expression of MT1M was associated with worse clinical prognosis, particularly in patients treated with 5-fluorouracil. Low expression of MT1M was indicative of poor overall survival (OS, HR 0.56 [95% CI 0.37-0.84], P < 0.005), first progression survival (FP, HR 0.54 [95% CI 0.36-0.79], P < 0.005), and post-progression survival (PPS, HR 0.65 [95% CI 0.45-0.94], P < 0.05). We also demonstrated that overexpression of MT1M inhibited cell proliferation and induced apoptosis in GC cells and in tumor xenografts, and it improved chemosensitivity to 5-fluorouracil. Furthermore, we found that MT1M overexpression could inhibit stem cell characteristics by targeting GLI1 and affecting GLI1 ubiquitination. Collectively, these findings indicated that MT1M may act as a tumor suppressor in GC and could serve as a potential therapeutic target to attenuate stemness and chemotherapy resistance of GC.

Topics: Cell Line, Tumor; Cell Proliferation; Fluorouracil; Gene Expression Regulation, Neoplastic; Hedgehog Proteins; Humans; Metallothionein; Stomach Neoplasms; Zinc Finger Protein GLI1

Gastric cancer (GC) is a heterogeneous disease with molecular diversity between and within tumors; therefore, searching for altered genes within this cancer is mandatory to reach the proper individualized targeted therapy. Expressions of Metallothionein (MT) and p21 are not uniform in various types of cancers and their predictive value in GC is controversial. This study aimed to assess the role of MT and p21 in intestinal-type GC and some of its precursor lesions.. Immunohistochemical staining for MT and p21 was applied on paraffin blocks belonging to 30 GCs and 51 benign gastric lesions/precancerous lesions [33 chronic gastritis and 18 chronic gastritis with gastric intestinal metaplasia (GIM)]; 27 of them were associated with H. pylori infection.. MT expression was dramatically increased while p21 expression was dramatically decreased from chronic gastritis to GIM to GC. In precancerous lesions, H. pylori-positive cases had significantly higher MT expression and lower p21 expression compared to H. pylori-negative cases. In GCs, decreased expression of both MT and p21 was associated with high-grade and advanced-stage cancers.. Both MT and p21 may have a role in the development and progression of GC, and both proteins may be useful for selecting targeted therapy for GC patients.

Topics: Cyclin-Dependent Kinase Inhibitor p21; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Metallothionein; Metaplasia; Precancerous Conditions; Stomach Neoplasms

Overall, 50 and 30 gastric antral biopsy samples of gastric cancer (case group) and gastritis (control group) patients were included into study, respectively. All biopsy samples were collected considering the exclusion criteria including patients with a history of consumption of tobacco, alcohol, and anti-. A negative correlation was revealed between age and clinical manifestations with the ΔCt value of the. The results of the current study opened a view for more investigation on the stunning roles of

Topics: Bacterial Proteins; Biopsy; Case-Control Studies; DNA, Complementary; Focal Adhesion Kinase 1; Gastric Mucosa; Gastritis; Gene Expression; Genotype; Helicobacter Infections; Helicobacter pylori; Humans; Metallothionein; Stomach Neoplasms

EBV-associated gastric cancer (EBVaGC) is characterized by high frequency of DNA methylation. In this study, we investigated how epigenetic alteration of host genome contributes to pathogenesis of EBVaGC through the analysis of transcriptomic and epigenomic datasets from NIH TCGA (The Cancer Genome Atlas) consortium. We identified that immune related genes (IRGs) is a group of host genes preferentially silenced in EBV-positive gastric cancers through DNA hypermethylation. Further functional characterizations of selected IRGs reveal their novel antiviral activity against not only EBV but also KSHV. In particular, we showed that metallothionein-1 (MT1) and homeobox A (HOXA) gene clusters are down-regulated via EBV-driven DNA hypermethylation. Several MT1 isoforms suppress EBV lytic replication and release of progeny virions as well as KSHV lytic reactivation, suggesting functional redundancy of these genes. In addition, single HOXA10 isoform exerts antiviral activity against both EBV and KSHV. We also confirmed the antiviral effect of other dysregulated IRGs, such as IRAK2 and MAL, in scenario of EBV and KSHV lytic reactivation. Collectively, our results demonstrated that epigenetic silencing of IRGs is a viral strategy to escape immune surveillance and promote viral propagation, which is overall beneficial to viral oncogenesis of human gamma-herpesviruses (EBV and KSHV), considering that these IRGs possess antiviral activities against these oncoviruses.

Topics: Biomarkers; DNA Methylation; Epigenesis, Genetic; Gammaherpesvirinae; Gene Expression Regulation, Viral; HEK293 Cells; Herpesviridae Infections; Homeobox A10 Proteins; Host-Pathogen Interactions; Humans; Incidence; Metallothionein; Stomach Neoplasms; Virus Activation; Virus Replication

Metallothionein 2A (MT2A) suppresses the progression of human gastric cancer potentially through an "MT2A-NF-κB pathway" with unclear mechanisms. This study explored the role of a transcription factor, myeloid zinc-finger 1 (MZF1), in MT2A-NF-κB pathway and its clinical significance in gastric cancer.. MZF1 expression and function in gastric cancer were investigated. MT2A exerts its anti-gastric cancer effects by complexing with MZF1 to target NFKBIA. MT2A/MZF1 may serve as a valuable prognostic marker and a novel therapeutic target for human gastric cancer.

Topics: Animals; Carcinogenesis; Cell Line; Cell Line, Tumor; Female; Gene Expression Regulation, Neoplastic; Humans; Kruppel-Like Transcription Factors; Metallothionein; Mice, Inbred BALB C; Mice, Nude; NF-kappa B; Protein Binding; RNA Interference; RNAi Therapeutics; Signal Transduction; Stomach Neoplasms; Xenograft Model Antitumor Assays

Metallothioneins (MTs) family comprises many isoforms, most of which are frequently dysregulated in a wide range of cancers. However, the expression pattern and exact role of each distinct MT family isoform which contributes to tumorigenesis, progression, and drug resistance of gastric cancer (GC) are still unclear.. Publicly available databases including Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier plotter, SurvExpress, MethHC, cBioportal, and GeneMANIA were accessed to perform an integrated bioinformatic analysis and try to detect fundamental relationships between each MT family member and GC.. Bioinformatic data indicated that the mRNA expression of all MT family members was almost lowly expressed in GC compared with normal gastric tissue (P<0.05), and patients with reduced mRNA expression of each individual MT member had inconsistent prognostic value (OS, FP, PPS), which depended on the individual isoform of MT. A negative correlation between the methylation in promoter region of majority of MT members and their mRNA expression was detected from MethHC database (p<0.001). Data downloaded from TCGA revealed that MTs were rarely mutated in GC patients and MT2A was frequently regulated by other three genes (FOS, JUN, SP1) in GC patients.. MTs were nearly downregulated, and distinct type of MT harbored different prognostic role in GC patients. Methylation in gene promoter region of MTs partially contributed to their reduced expression in GC. Our comprehensive analyses from multiple independent databases may further lead researches to explore MT-targeting reagents or potential diagnostic and prognostic markers for GC patients.

Topics: Biomarkers, Tumor; Carcinogenesis; Disease Progression; Disease-Free Survival; DNA Methylation; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Humans; Kaplan-Meier Estimate; Male; Metallothionein; Multigene Family; Prognosis; RNA, Messenger; Stomach Neoplasms

Emerging evidence points towards an important role of long noncoding RNAs (lncRNAs) in the tumorigenesis and progression of gastric cancer (GC). MT1JP has recently been reported to be differentially expressed and act as a tumor suppressor in different tumors, with its mechanisms not fully understood in GC.. RT-qPCR was used to detect the expression of MT1JP, miR-214-3p and RUNX3 in tumor tissues and cell lines of GC. The CCK-8 assay, colony formation, Transwell assay and wound healing assay were used to evaluate the proliferation, invasion and migration of GC cells, respectively. Bioinformatics analysis and luciferase reporter assay were performed to disclose the interaction between MT1JP, miR-214-3p and RUNX3. Western blot and immunofluorescence were applied to assess the downstream signaling of RUNX3.. MT1JP was found downregulated in GC tissues and cells. Low expression of MT1JP was significantly correlated with advanced TNM stage and lymphatic metastasis. The expression of plasma MT1JP was also found decreased in GC patients compared to healthy controls, with an area under the ROC curve (AUC) of 0.649 for diagnosis of GC. Gain- and loss-of-function of MT1JP revealed that MT1JP functioned as a ceRNA for miR-214-3p to facilitate RUNX3 expression and then upregulated p21 and Bim levels suppressing GC cell proliferation, invasion and migration, and promoting apoptosis. Furthermore, MT1JP overexpression suppressed tumor growth and inhibited the expression of miR-214-3p and proliferation antigen Ki-67, but increased the expression of RUNX3, p21 and Bim in vivo.. Our results suggest a potential ceRNA regulatory network involving MT1JP regulates RUNX3 expression by competitively binding endogenous miR-214-3p in tumorigenesis and progression of GC. This mechanism may contribute to a better understanding of GC pathogenesis and provide potential therapeutic strategy for GC.

Topics: Animals; Cell Line, Tumor; Cell Movement; Cell Proliferation; Core Binding Factor Alpha 3 Subunit; Down-Regulation; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Metallothionein; Mice, Nude; MicroRNAs; Middle Aged; Neoplasm Invasiveness; RNA, Long Noncoding; Signal Transduction; Stomach Neoplasms

Metallothionein 2A (MT2A) and nuclear factor-kappaB (NF-κB) are both involved in carcinogenesis and cancer chemosensitivity. We previously showed decreased expression of MT2A and IκB-α in human gastric cancer (GC) associated with poor prognosis of GC patients. The present study investigated the effect of diallyl trisulfide (DATS), a garlic-derived compound, and docetaxel (DOC) on regulation of MT2A in relation to NF-κB in GC cells.. DATS attenuated NF-κB signaling in GC cells, resulting in G2/M cell cycle arrest and apoptosis, culminating in the inhibition of cell proliferation and tumorigenesis in nude mice. The anti-GC effect of DATS was attributable to its capacity to epigenetically upregulate MT2A, which in turn enhanced transcription of IκB-α to suppress NF-κB activation in GC cells. The combination of DATS with DOC exhibited a synergistic anti-GC activity accompanied by MT2A upregulation and NF-κB inactivation. Histopathologic analysis of GC specimens from patients showed a significant increase in MT2A expression following DOC treatment. GC patients with high MT2A expression in tumor specimens showed significantly improved response to chemotherapy and prolonged survival compared with those with low MT2A expression in tumors.. We conclude that DATS exerts its anti-GC activity and enhances chemosensitivity of GC to DOC by epigenetic upregulation of MT2A to attenuate NF-κB signaling. Our findings delineate a mechanistic basis of MT2A/NF-κB signaling for DATS- and DOC-mediated anti-GC effects, suggesting that MT2A may be a chemosensitivity indicator in GC patients receiving DOC-based treatment and a promising target for more effective treatment of GC by combination of DATS and DOC. Antioxid. Redox Signal. 24, 839-854.

Topics: Adult; Aged; Allyl Compounds; Animals; Antineoplastic Agents; Apoptosis; Biomarkers, Tumor; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Docetaxel; Drug Resistance, Neoplasm; Drug Synergism; Epigenesis, Genetic; Female; Gene Expression; Gene Expression Regulation, Neoplastic; Humans; Male; Metallothionein; Mice, Nude; Middle Aged; NF-kappa B; Stomach Neoplasms; Sulfides; Taxoids; Transcriptional Activation; Up-Regulation; Xenograft Model Antitumor Assays; Young Adult

Copy number variation (CNV) and abnormal expression of microRNAs (miRNAs) always lead to deregulation of genes in cancer, including gastric cancer (GC). However, little is known about how CNVs affect the expression of miRNAs. By integrating CNV and miRNA profiles in the same samples, we identified eight miRNAs (miR-1274a, miR-196b, miR-4298, miR-181c, miR-181d, miR-23a, miR-27a and miR-24-2) that were located in the amplified regions and were upregulated in GC. In particular, amplification of miR-23a-27a-24-2 cluster and miR-181c-181d cluster frequently occurred at 19p13.13 and were confirmed by genomic real-time PCR in another 25 paired GC samples. Moreover, in situ hybridization (ISH) experiments represented that mature miR-23a was increased in GCs (75.5%, 40/53) compared with matched normal tissues (28.6%, 14/49, P = 0.001). Knocking down of miR-23a expression inhibited BGC823 cell growth in vitro and in vivo. In addition, the potential target genes of miR-23a were investigated by integration of mRNA profile and miRNA TargetScan predictions, we found that upregulation of miR-23a and downregulation of metallothionein 2A (MT2A) were detected simultaneously in 70% (7/10) of the miRNA and mRNA profiles. Furthermore, an inverse correlation between miR-23a and MT2A expression was detected in GCs and normal tissues. Through combining luciferase assay, we confirmed that MT2A is a potential target of miR-23a. In conclusion, these results suggest that integration of CNV-miRNA-mRNA profiling is a powerful tool for identifying molecular signatures, and that miR-23a might play a role in regulating MT2A expression in GC.

Topics: Animals; Blotting, Western; Cell Line, Tumor; Computational Biology; Humans; Immunohistochemistry; In Situ Hybridization; Metallothionein; Mice; Mice, Nude; MicroRNAs; Real-Time Polymerase Chain Reaction; RNA Interference; Stomach Neoplasms

Metallothionein 2A (MT2A) as a stress protein, plays a protective role in gastric mucosal barrier. Its role in the development of gastric cancer (GC) is unclear. The mechanism of MT2A will be investigated in gastric tumorigenesis.. MT2A expression was detected in 973 gastric specimens. The biological function was determined through ectopic expressing MT2A in vitro and in vivo. The possible downstream effectors of MT2A were investigated in NF-κB signaling. The protein levels of MT2A, IκB-α and p-IκB-α (ser32/36) expression were analyzed in a subset of 258 patients by IHC staining. The prognostic effects of MT2A, status of IκB-α and TNM stage were evaluated using the Kaplan-Meier method and compared using the log-rank test.. Decreased MT2A expression was detected in cell lines and primary tumors of GC. In clinical data, loss of MT2A (MT2A + in Normal (n =171, 76.0%); Intestinal metaplasia (n = 118, 50.8%); GC (n = 684. 22.4%, P < 0.001)) was associated with poor prognosis (P < 0.001), advanced TNM stage (P = 0.05), and down-regulation of IκB-α expression (P < 0.001). Furthermore, MT2A was the independent prognostic signature segregated from the status of IκB-α and pathological features. In addition, MT2A inhibited cell growth through apoptosis and G2/M arrest, which negatively regulated NF-κB pathway through up-regulation of IκB-α and down-regulation of p-IκB-α and cyclin D1 expression.. MT2A might play a tumor suppressive activity through inhibiting NF-κB signaling and may be a prognostic biomarker and potential target for individual therapy of GC patients.

Topics: Adult; Aged; Aged, 80 and over; Cell Line, Tumor; Cyclin D1; Female; Gene Expression Regulation, Neoplastic; Humans; I-kappa B Proteins; Immunohistochemistry; Male; Metallothionein; Middle Aged; NF-kappa B; NF-KappaB Inhibitor alpha; Prognosis; Signal Transduction; Stomach Neoplasms; Treatment Outcome; Up-Regulation; Young Adult

Dysregulated metallothionein 2A (MT2A) has been implicated in carcinogenesis. The purpose of this study was to investigate the expression of MT2A in gastric cancer (GC) and its correlation with prognosis.. Reverse transcription-polymerase chain reaction and real-time polymerase chain reaction were used to detect the mRNA expression of MT2A in 12 GC cell lines, normal gastric epithelial GES-1 cells, and 36 GC and adjacent normal tissues. MT2A protein expression was determined in 258 GC tissues and 171 adjacent normal tissues by immunohistochemistry.. MT2A mRNA expression was lower in GC cells and primary tumors than in GES-1 cells and adjacent normal tissues, respectively. High protein expression of MT2A was present in 130 of 171 normal tissues (76.0%) and in 56 of 258 GC tissues (21.7%; P < 0.001). MT2A protein expression was higher in well/moderately differentiated GC (22/54; 40.7%) than in poorly differentiated GC (34/204; 16.7%; P < 0.001). Moreover, the protein expression of MT2A was lower in diffuse-type GC (6/82; 7.3%) than in intestinal-type GC (50/176; 28.4%; P = 0.0001). Importantly, MT2A expression was an independent prognostic factor for GC, and decreased MT2A expression was associated with poor clinical outcome (P < 0.001). The expression status of MT2A could predict prognosis in intestinal and diffuse-type GCs.. Expression status of MT2A might be a useful prognostic biomarker for GC, especially when used in combination with Lauren's classification.

Topics: Adult; Aged; Cell Line, Tumor; Female; Humans; Logistic Models; Male; Metallothionein; MicroRNAs; Middle Aged; Prognosis; Proportional Hazards Models; Stomach Neoplasms

Metallothionein (MT), a low-molecular-weight protein with a high affinity for divalent heavy metal ions, is involved in many pathophysiological processes, including metal homeostasis, detoxification, cell proliferation and protection against oxidative damage. We previously found that MT in gastric mucosa plays a role in protecting against Helicobacter pylori (H. pylori)-induced gastritis at the early stage of infection. H. pylori-induced chronic gastric inflammation is shown to be associated with gastric carcinogenesis. Thus, to examine whether gastric MT contributes to protection against H. pylori-induced chronic inflammation, we compared histological changes in the gastric mucosa of MT-null and the wild-type mice at 53 weeks after inoculation three times with H. pylori SS1. As a result, we observed disruption of the gastric mucosa in MT-null mice, but not in the wild-type mice, even at the late stage of H. pylori-infection. Evaluation of pathological changes in gastric specimens by the updated Sydney grading system revealed that scores related to chronic inflammation and polymorphonuclear cell activity were higher in infected MT-null mice than those in the wild-type mice. Furthermore, a higher score for metaplasia was also observed in the MT-null stomach. These results suggested that MT might be involved in protecting against H. pylori-induced gastric chronic inflammation associated with carcinogenesis.

Topics: Animals; Chronic Disease; Disease Progression; Female; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Male; Metallothionein; Mice; Stomach Neoplasms

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that account for about 2% of gastric tumors. Metallothioneins (MTs) are multifunctional proteins associated with carcinogenesis and known to be coded by 10 functional MT genes. This study evaluated MT mRNA and protein expression in GISTs and compared the expression levels with gastric carcinomas. An immunohistochemical study of MT protein expression was performed in 15 GISTs (specifically located in the stomach) and 38 early stage gastric carcinomas. The percentage of cells stained and intensity of staining were determined. MT-2A mRNA expression was investigated in 6 GISTs and 6 early stage gastric carcinoma patients. All GISTs displayed positive nuclear immunostaining, with most GISTs having predominantly mildly stained nuclei (93.3%). On the other hand, 37 out of 38 gastric carcinoma cases were positively stained for nuclear MT with 24 cases (63.2%) exhibiting predominantly mild nuclear staining, 7 cases (18.4%) moderate nuclear staining, and 6 cases (15.8%) strong nuclear staining. Nuclear MT expression was found to be significantly lower in GIST samples when compared with gastric carcinoma tissues based on the percentage stained and immunoreactive score. We then established that the MT-2A gene transcript was the most abundant MT isoform in MKN28 gastric cancer cells and analyzed its expression in GIST and gastric carcinoma tissues. We found that GISTs had significantly lower MT-2A mRNA levels than gastric carcinoma tissues. Lower MT-2A gene expression and nuclear MT protein expression in GISTs when compared with gastric carcinomas may reflect their different underlying biology and divergent histogenesis.

Topics: Adenocarcinoma; Biomarkers, Tumor; Cell Line, Tumor; Cell Nucleus; Gastrointestinal Stromal Tumors; Humans; Metallothionein; Neoplasm Staging; RNA, Messenger; Stomach Neoplasms

Metallothionein (MT) has a proven relationship with various kinds of cancer and reduces tissue damage. Helicobacter pylori (H. pylori) infection is associated with the alteration of gastric epithelial cell cycle events, a condition implicated in the initiation and development of gastric cancer. This study investigates the role of MT in H. pylori-induced gastritis with or without early gastric cancer (ECG) and evaluates the effect on MT expression after eradication therapy.. Gastric biopsy samples were immunohistochemically examined for MT expression in 36 H. pylori-negative patients without ECG and 98 positive patients with or without ECG. Real time polymerase chain reaction was performed in 14 antral biopsy samples with or without H. pylori. The severity of gastritis was also evaluated according to the updated Sydney System. In 31 successfully eradicated patients, the above assessment was repeated for two consecutive years.. MT expression was higher in H. pylori-negative patients than in positive patients (P < 0.01). Moreover, in the corpus it was higher in H. pylori-positive patients without ECG compared to those with ECG (P < 0.05). The MT labeling index had a negative correlation with the severity of gastritis (P < 0.01). A positive correlation was shown between the MT labeling index and apoptosis: proliferation ratio (r = 0.41, P < 0.01). The MT labeling index in H. pylori-positive patients was gradually recovered after eradication (P < 0.05).. The decrease of MT expression cannot prevent tissue damage in H. pylori-positive gastric mucosa and leads to more severe gastritis. This phenomenon may be attributed to gastric carcinogenesis. H. pylori eradication increases MT expression and may reduce the risk of ECG.

Topics: Anti-Bacterial Agents; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Humans; Metallothionein; Stomach Neoplasms

As a significant number of curatively treated gastric cancer patients will ultimately relapse, there is an urgent need to investigate new prognostic markers for identification of high-risk patients. In this study, we investigated the possible role of molecular markers involved in cell cycle regulation (B1 and D3 cyclins, and p27) and cell protection (metallothionein, MT) in predicting tumor behavior and clinical outcome in gastric cancer patients.. Analysis of the above indicators was performed by immunohistochemistry on 73 gastric cancer patient samples and 25 normal gastric mucosa specimens.. Normal gastric mucosa cells displayed low expressions of B1 and D3 cyclins and MT, and intense p27 staining. Conversely, gastric tumor cells showed higher cyclin D3 and MT, and lower p27 expressions. B1 cyclin expressions were not different between normal and tumor tissue. p27 and MT expressions were altered in almost all cancer samples, and were strongly correlated with tumor progression. Advanced extent of the primary tumor, nodal metastasis, low p27, and high MT expressions were the best combination of variables for prediction of poor clinical outcome. Each marker predicted outcome better than staging based on tumor-node (TNM) system. Survival and recurrence rates decreased as molecular alterations increased. Finally, molecular profile determination correctly predicted the prognosis in patients with same TNM stage.. p27 and MT expressions strongly correlated with clinical outcome allowing to identify an unfavorable group of patients that may benefit from tailored treatments. The role of B1 and D3 cyclins in gastric cancer remains to be elucidated.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers, Tumor; Cyclin B; Cyclin B1; Cyclin D3; Cyclins; Down-Regulation; Female; Gastric Mucosa; Humans; Immunohistochemistry; Lymphatic Metastasis; Male; Metallothionein; Middle Aged; Prognosis; Proliferating Cell Nuclear Antigen; Stomach Neoplasms; Survival Rate; Treatment Outcome

To gain insight into clinically relevant mechanisms of irinotecan resistance, we undertook oligonucleotide microarray analyses on paired malignant effusion samples obtained from eight gastric cancer patients treated with weekly irinotecan. Pretreatment and posttreatment (48 h) effusion samples were obtained for each patient, and the change in expression profile was compared between clinical responders and nonresponders. When differences in the expression of genes were examined using SAM (Significance Analysis of Microarrays) software, five isoforms of the metallothionein family were identified to have significantly higher signal log ratios in five nonresponders, compared with three responders. Compared with control cells, metallothionein 1X (MT1X)-transfected AGS cells showed a 1.4-fold higher irinotecan IC(50) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and tended to form more colonies. These findings collectively suggest that irinotecan-induced up-regulation of metallothionein might be associated with irinotecan resistance in patients with gastric cancer, although it remains to be confirmed in a larger data set.

Topics: Adult; Aged; Antineoplastic Agents, Phytogenic; Camptothecin; Drug Resistance, Neoplasm; Female; Humans; Irinotecan; Male; Metallothionein; Middle Aged; Oligonucleotide Array Sequence Analysis; Stomach Neoplasms

Reactive oxygen species (ROS) cause macromolecular damage and may play an important role in tumor development. Superoxide dismutase (SOD) and metallothionein (MT) serve as initial and final defense mechanisms, respectively, against ROS. We hypothesized that the inducibility of Mn-SOD and MT mRNA by paraquat, an intracellular superoxide generator, might be altered in lymphocytes of gastric cancer patients. The inducibility of Mn-SOD mRNA by paraquat in lymphocytes of 19 normal subjects and the 14 gastric cancer patients was 162.4 +/- 16.7% and 87.9 +/- 9.5%, respectively (P = 0.001). The inducibility of MT mRNA by paraquat in the normal subjects and the gastric cancer patients was 126.7 +/- 15.8% and 115.4 +/- 12.9%, respectively. This suggests that the failure of Mn-SOD mRNA induction by oxidative stress in peripheral lymphocytes may be involved in the development of gastric cancer and may be of value in predicting the future occurrence of gastric cancer. In addition, the wide variation in Mn-SOD and MT mRNA levels among normal subjects may reflect different susceptibilities to diseases including cancer.

Topics: Adult; Aged; Enzyme Induction; Female; Fluorescent Dyes; Humans; Lymphocytes; Male; Metallothionein; Middle Aged; Oxidative Stress; Paraquat; Reactive Oxygen Species; RNA, Messenger; Stomach Neoplasms; Superoxide Dismutase

Differential display is a valuable tool for the identification of differentially expressed genes in human carcinogenesis and development. The search for differentially expressed genes in gastric cancer and its premalignant lesions may help to define molecular alterations in the gastric mucosa that may precede the development of gastric cancer. Using the differential display technique, we identified a cDNA fragment, encoding metallothionein (MT) IIa mRNA. We performed immunohistochemical analysis using a monoclonal antibody directed against human MT and tissues obtained from 34 patients with gastric cancer and 20 healthy individuals to determine the expression and localization of MT in gastric cancer and its associated premalignant lesions and to correlate our findings with histomorphological features and Helicobacter pylori status. In addition, MT expression was assessed in gastric tissues obtained from patients with gastric cancer and first-degree relatives of patients with gastric cancers and healthy individuals using reverse transcription-PCR analysis. Northern blot analysis confirmed the overexpression of MT IIa in gastric cancer. In the normal gastric tissues, no MT immunoreactivity was observed at the superficial gastric epithelium toward the top of gastric glands. However, MT immunoreactivity was detected at the foveolar neck of the gastric glands. Immunohistochemical analysis revealed an intense MT immunoreactivity in gastric cancer cells, independent of tumor stage, grade of differentiation, or tumor type. Furthermore, areas of dysplasia and intestinal metaplasia also exhibited intense MT immunoreactivity. Reverse transcription-PCR analysis of gastric biopsies obtained from first-degree relatives of patients with gastric cancer revealed the frequent expression of MT Ia in this high-risk group as compared with healthy subjects (P < 0.01). The overexpression of MT in gastric cancer and the expression of MT in intestinal metaplasia and dysplasia, as well as the expression of MT in the gastric mucosa of first-degree relatives of patients with gastric cancer, point to a role for MT in the early process of malignant transformation of the gastric mucosa.

Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Female; Gastric Mucosa; Humans; Intestinal Neoplasms; Male; Metallothionein; Metaplasia; Middle Aged; Precancerous Conditions; Reference Values; Reverse Transcriptase Polymerase Chain Reaction; Stomach Neoplasms

Utilising a specific monoclonal mouse antibody (E9), metallothionein (MT) expression has been immunohistochemically investigated in 112 formalin-fixed paraffin-embedded surgical gastric samples, 38 of which were early carcinomas (EGC) and 74 advanced ones (AGC); clinico-pathological details and follow-up data (ranging from 3 to 197 months, mean 60.5 months) were available. Eighty-nine portions of gastric mucosa adjacent to examined carcinomas (transitional mucosa) were also analysed; in addition, 22 biopsies of normal gastric mucosa were studied as tissue control. The MT immunoreactivity was evaluated by staining and intensity-distribution scores. A various MT positivity was appreciable in the cytoplasm and nucleus of antrum or body gastric epithelial cells in 100% of normal control biopsies. 75/112 (67%) gastric carcinomas showed MT immunoreactivity with a significant lower expression in AGC. No relationships were encountered between MT immunostaining and clinico-pathological data; in addition, no difference in the Kaplan-Meier survival curves of patients with various MT expression was achieved. When the transitional mucosa was examined, 84/89 (94%) samples were stained although the immunoreaction was not always concordant with that encountered in adjacent carcinomatous elements. The significant statistical decrease of MT scores observed by us moving from normal to neoplastic gastric mucosa allows us to exclude the hypothesis of an overexpression of MT in gastric carcinomas.

Topics: Adult; Aged; Aged, 80 and over; Carcinoma; Cell Nucleus; Cytoplasm; Female; Gastric Mucosa; Humans; Immunohistochemistry; Male; Metallothionein; Middle Aged; Prognosis; Stomach Neoplasms; Survival Analysis

Metallothionein (MT) is a small thiol-rich metalloprotein with antioxidant properties, involved in tumour pathophysiology and therapy resistance. In order to assess the contribution of MT in gastrointestinal carcinogenesis, this study examined both the MT content by radioimmunoassay and the MT localization by immunohistochemistry in pairs of neoplastic and normal-appearing human gastrointestinal tissues. In addition, the relationship between MT expression and major clinicopathological parameters was assessed. The MT concentration of gastric carcinomas and of colorectal adenomas, carcinomas, and liver metastases was found to be significantly lower than that of corresponding normal-appearing tissue. A relatively high MT content, however, was found to be associated with the villous character of colorectal adenomas and with the Dukes' stage of colorectal carcinomas, indicating a relationship between MT level and malignant potential. Immunohistochemical evaluation showed a fairly good correlation with these quantitative data. MT was found to be expressed at a low level and in a patchy pattern in the gastrointestinal neoplastic and metastatic tissues, whereas in normal-appearing gastrointestinal mucosa MT was uniformly distributed in the cytoplasm and/or nucleus of apical cells. Although in the gastric cancer patients no association was found between the MT concentration and the clinicopathological parameters, the strong MT expression in areas with intestinal metaplasia, known to have neoplastic potential, further points to a relationship between this antioxidant metalloprotein and the malignant character of cells. Gastrointestinal neoplasms are apparently accompanied by a low level and decreased expression of MT, but those with a relatively high level seem to have an increased malignant potential. Further studies will be required to determine the clinical relevance of these observations.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Colorectal Neoplasms; Female; Fluorescent Antibody Technique, Indirect; Humans; Liver Neoplasms; Male; Metallothionein; Middle Aged; Radioimmunoassay; Stomach Neoplasms