metallothionein and Laryngeal-Neoplasms

MCM2, MCM3 and MCM7 are minichromosome maintenance proteins found in dividing cells and they play a role in DNA synthesis. Increased MCM expression level is observed in cells of different cancer types. Additionally, metallothioneins (MT-I/II) are involved in control of cell proliferation and differentiation and changes of their expression are observed in many types of cancer. Ki-67 is known cancer cell proliferation antigen currently used in prognostic evaluation. The study material consisted of 83 laryngeal squamous cell cancer (LSCC) cases and 10 benign hypertrophic lesions of larynx epithelium as a control group. For the present study, laryngeal cancer cell line HEp-2 and human keratinocytes were employed, and to evaluate expression of all the markers, immunohistochemical method (IHC), immunofluorescence (IF) and western blot analysis were used. Statistical analysis showed strong positive correlation between expression of MCM2, MCM3, MCM7 and Ki-67 antigen in LSCC. Additionally, moderate positive correlation was observed between MCM3 and MT-I/II expression. In cancer cells, the level of expression of MCM3, MCM2, MCM7 and Ki-67 markers was increasing with the grade of LSCC malignancy. IF and western blot analysis showed higher MCM2, MCM3, MCM7 expression in HEp-2 cells in comparison to their expression in keratinocytes. MCM proteins might be useful markers of cell proliferation in LSCC.

Topics: Adult; Aged; Biomarkers, Tumor; Carcinoma, Squamous Cell; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; DNA-Binding Proteins; Female; Head and Neck Neoplasms; Humans; Keratinocytes; Ki-67 Antigen; Laryngeal Neoplasms; Male; Metallothionein; Middle Aged; Minichromosome Maintenance Proteins; Squamous Cell Carcinoma of Head and Neck

Metallothioneins are intracellular regulators of many biological mechanisms including differentiation, proliferation, angiogenesis and invasion, which are crucial processes in carcinogenesis. This study examines the association between three single-nucleotide polymorphisms at loci -5 A/G (rs28366003) and -209 A/G (rs1610216) in the core promoter region and at locus +838 C/G (rs10636) in 3'UTR region of the metallothionein 2A (MT2A) gene with squamous cell laryngeal cancer (SCLC) risk, as well as with tumor invasiveness according to tumor front grading (TFG). Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism technique in 323 genetically unrelated individuals with SCLC and 418 randomly selected healthy volunteers. Only one SNP (rs28366003) was significantly related to laryngeal cancer in the study population. Compared with homozygous common allele carriers, heterozygous and homozygous for the G variant had significantly increased risk of SCLC [adjusted odds ratio (OR) = 2.90, 95 % confidence interval (CI) 1.53-5.21, p dominant < 0.001]. The A/G allele carriers at rs28366003 MT2A were at higher risk of SCLC development (OR = 2.63, 95 % CI 1.41-2.85, p < 0.001]. There was a significant association between the rs28366003 and stage and TFG classification. Most carriers of minor allele had a higher stage (OR = 2.76, 95 % CI 1.11-7.52, p = 0.03), increased cancer aggressiveness, as defined by a higher total TFG score (>18 points) (OR = 3.76, 95 % CI 1.15-12.56, p = 0.03) and diffuse tumor growth (OR = 5.86, 95 % Cl 0.72-44.79, p = 0.08). The results of this study raise a possibility that a genetic variation of MT2A may be implicated in the etiology of laryngeal cancer in a Polish population.

Topics: 3' Untranslated Regions; Aged; Aged, 80 and over; Biomarkers, Tumor; Case-Control Studies; Female; Genetic Predisposition to Disease; Genetics, Population; Heterozygote; Humans; Laryngeal Neoplasms; Male; Metallothionein; Middle Aged; Neoplasms, Squamous Cell; Poland; Polymorphism, Single Nucleotide; Promoter Regions, Genetic; White People

Metallothioneins (MTs) are low molecular weight, cysteine-rich heavy metal-binding proteins which participate in the mechanisms of Zn homeostasis, and protect against toxic metals. MTs contain metal-thiolate cluster groups and suppress metal toxicity by binding to them. The aim of this study was to determine the -5 A/G (rs28366003) single-nucleotide polymorphism (SNP) in the core promoter region of the MT2A gene and to investigate its effect on allele-specific gene expression and Cd, Zn and Cu content in squamous cell laryngeal cancer (SCC) and non-cancerous laryngeal mucosa (NCM) as a control. The MT2A promoter region -5 A/G SNP was determined by restriction fragment length polymorphism using 323 SCC and 116 NCM. MT2A gene analysis was performed by quantitative real-time PCR. The frequency of A allele carriage was 94.2% and 91.8% in SCC and NCM, respectively, while G allele carriage was detected in 5.8% and 8.2% of SCC and NCM samples, respectively. As a result, a significant association was identified between the -5 A/G SNP in the MT2A gene with mRNA expression in both groups. Metal levels were analyzed by flame atomic absorption spectrometry. The significant differences were identified between A/A and both the A/G and G/G genotypes, with regard to the concentration of the contaminating metal. The Spearman rank correlation results showed that the MT2A expression and Cd, Zn, Cu levels were negatively correlated. Results obtained in this study suggest that -5 A/G SNP in MT2A gene may have an effect on allele-specific gene expression and accumulation of metal levels in laryngeal cancer.

Topics: Aged; Alleles; Cadmium; Copper; Female; Humans; Laryngeal Neoplasms; Male; Metallothionein; Metals, Heavy; Middle Aged; Polymorphism, Single Nucleotide; Promoter Regions, Genetic; Zinc

The purpose of the study was twofold: 1) to search for potential biomarkers that were overexpressed in cell lines that could represent both a clinical premalignant (immortalized) and a malignant state, and 2) to attempt to correlate metallothionein gene expression with clinical outcome in laryngeal carcinoma.. A series of in vitro experiments were used to unearth differentially expressed genes among normal, immortalized and tumorigenic cell lines. Secondarily, a retrospective analysis was undertaken.. Differential display analysis was conducted to identify differentially expressed genes between human papillomavirus-infected immortalized HOK16B and benzo[ ]pyrene-derived tumorigenic cell line, HOK16B-BaP-T. The cell-specific expressions were examined by Northern blot analysis and compared with other known immortalized and cancer cell lines. Immunohistochemical staining was also conducted to localize metallothionein (MT I/II) protein expression among the different cell lines studied. A retrospective analysis of laryngeal specimens from archival tissues of 29 cancer patients who underwent primary surgical resection was also undertaken after immunohistochemical staining.. Twenty-one differentially expressed complementary cDNA clones, both novel and known, were identified using the differential display analysis. Northern blot analysis confirmed that clone 6 hybridized to a 1.6-kb RNA in HOK16B-Bap-T cell line. Clone 4 showed decreased expression in immortalized and cancer cell compared with NHOK. MT I/II transcript was observed in HOK16B, which was further elevated in HOK16B-Bap-T. Retrospective analysis showed that high immunoreactivity to MT I/II in surgically resected laryngeal cancer specimen correlated with increased frequency of recurrence within 2 years of surgery.. These findings suggest that clone 4 may potentially function as a tumor suppressor gene, which may be significant in tumor progression and invasion. Clone 6 may participate in viral-mediated oncogenic transformation of normal cells. Clone 6 may also have potential as a tumor maker differentiating normal from malignant tissue, as in the determination of surgical resection margins. MT I/II gene product may serve as a prognostic biomarker for laryngeal squamous cell carcinoma. The differentially expressed genes and gene products may serve as sensitive biomarkers for improved early detection, diagnosis, and prognosis of head and neck squamous cell carcinoma.

Topics: Bacterial Proteins; Bacterial Toxins; Blotting, Northern; Carcinoma, Squamous Cell; Cell Culture Techniques; Clone Cells; DNA, Complementary; Escherichia coli Proteins; Female; Gene Expression; Genes, Tumor Suppressor; Humans; Immunohistochemistry; Laryngeal Neoplasms; Male; Metallothionein; Middle Aged; Neoplasm Staging; Retrospective Studies; RNA

In this study we evaluated the immunohistochemical expression of metallothionein (MT) in 44 squamous cell carcinomas, 14 cases of in situ carcinoma, 47 with epithelial dysplasia, 11 papillomas and 21 cases of keratosis. The MT expression was studied in correlation with p53 protein expression and the proliferative cell nuclear antigen (PCNA). The monoclonal antibodies E9 (anti-MT), DO-7 (which reacts with a denaturation-resistant epitope in wild-type and mutant p53) and PC10 (anti-PCNA) on formalin-fixed, paraffin-embedded tissue were used employing the immunoperoxidase (ABC) method. The immunohistochemical localization of MT has shown its rather ubiquitous presence in the cytoplasm and nucleus of both benign and malignant epithelial cells. In most cases the adjacent "normal" epithelium showed low positivity in the basal portion. The mean value of metallothionein expression was 35.73 in squamous cell carcinomas, 32.21 in in situ carcinomas, 11.86 in dysplastic epithelium, 5.10 in papillomas and 3.5 in keratosis. In carcinomas, low MT expression (< 10% of neoplastic cells) was observed in 20.5% of the cases, moderate (10%-50% of neoplastic cells) in 54.5% and extensive expression (> 50% of neoplastic cells) in 25% of the cases. We did not find any statistically significant difference of MT expression between in situ and infiltrating carcinomas, while we did observe a significant difference between carcinomas and the other groups. There was a statistically significant difference in the PCNA values in both benign and malignant lesions, while no statistically significant difference was observed in p53 protein expression in the above groups. A positive correlation between MT expression and the PCNA value (p < 0.0001) in the benign and malignant groups was detected. The PCNA value was also correlated with the p53 protein expression (p = 0.001). No correlation was found between MT and p53 protein expression. In conclusion, these results suggest that the MT expression may play a role in the development of malignant disease of the larynx, from the early phase of laryngeal carcinogenesis, independently from the p53 expression. It is also possible to contribute to tumour cell growth, as determined by the PCNA score.

Topics: Adult; Aged; Aged, 80 and over; Carcinoma in Situ; Carcinoma, Squamous Cell; Epithelial Cells; Female; Humans; Immunoenzyme Techniques; Keratosis; Laryngeal Neoplasms; Male; Metallothionein; Middle Aged; Papilloma; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Tumor Suppressor Protein p53

The Fas receptor appears to be commonly expressed in all morphological types of epithelial laryngeal hyperplasia (HP). Fas-mediated apoptotic cell death would thus be a possible phenomenon in these lesions. We observed more anti-apoptotic bcl-2 protein in epithelia with simple HP compared to the more advanced types of HP. It is suggested that in simple HP there is not yet a need for an early selection for cell death. The observed overexpression of metallothionein (MT) in the basal layers of simple HP would also support such a theory. These basal cells are dividing, non-apoptotic cells, which have not yet been selected for death. All 20 cysteine residues in MT are involved in metal binding, interfering with the intracellular redox balance, and thereby possibly inhibiting certain apoptotic signals. MIB-1 positivity was found only in the atypical HP, CIS, and invasive carcinomas. Intuition suggests that high labelling would be associated with poor prognosis. The degree of apoptosis, evaluated by TUNEL, did not show any differences between different types of epithelia. Although TUNEL is sensitive and rather specific, we emphasise that all TUNEL positive cells have apoptotic type morphology, confirming good and appropriate use of the technique.

Topics: Apoptosis; Carcinoma in Situ; Carcinoma, Squamous Cell; Epithelium; Fas Ligand Protein; Humans; Hyperplasia; Laryngeal Diseases; Laryngeal Mucosa; Laryngeal Neoplasms; Membrane Glycoproteins; Metallothionein; Neoplasm Invasiveness; Precancerous Conditions; Proto-Oncogene Proteins c-bcl-2