Death-associated Protein Kinase Promoter Hypermethylation Research Articles

Clinicopathological significance of DAPK gene promoter hypermethylation in non-small cell lung cancer: A meta-analysis.

Death-associated protein kinase (DAPK) has a strong function of tumor suppression involving apoptosis regulation, autophagy, and metastasis inhibition. Hypermethylation of CpG islands in DAPK gene promoter region is one of the important ways to inactivate this tumor suppressor gene, which might promote lung carcinogenesis. However, the clinicopathological significance of the DAPK promoter hypermethylation in lung cancer remains unclear. In this study, we performed a meta-analysis trying to estimate the clinicopathological significance of DAPK promoter hypermethylation in non-small cell lung cancer (NSCLC). A detailed literature search for publications relevant to DAPK gene promoter methylation and NSCLC was made in PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, CSTJ, Wanfang databases, and SinoMed (CBM). The random-effects model and fixed-effects model were utilized to pool the relative ratio based on the heterogeneity test in the meta-analysis. A total of 41 studies with 3348 patients were included. The frequency of DAPK methylation was significantly higher in NSCLC than in non-malignant control (odds ratio (OR) = 6.88, 95% confidence interval (CI): 4.17-11.35, P < 0.00001). The pooled results also showed that DAPK gene promoter hypermethylation was significantly associated with poor prognosis for overall survival in patients with NSCLC (hazard ratio: 1.23, 95% CI:1.01-1.52, P = 0.04). Moreover, DAPK gene promoter hypermethylation was significantly associated with squamous cell carcinoma (OR: 1.25, 95% CI: 1.01-1.54, P = 0.04) and smoking behavior (OR: 1.42, 95% CI: 1.04-1.93, P = 0.03) but not with TNM stage, tumor differentiation, age, or gender. DAPK promoter hypermethylation might be a candidate diagnostic and prognostic tumor marker for NSCLC.

Meta-analysis: Assocation between promoter hypermethylation of DAPK (Death-Associated Protein Kinase) and cervical cancer

Purpose: Death-associated protein kinase (DAPK or DAPK1) is an important tumor suppressor protein that involved in the regulation of cell activities. The aberrant methylation of DAPK promoter has been reported in patients with cervical cancer. However, the association between of DAPK1 and cervical cancer was not always unification, in previous studies. Therefore, in current study, a meta-analysis was performed for association of between DAPK gene’s promoter hypermethylated and cervical cancer.&#x0D; Methods: A systematic literature analysis was conducted based on the previous studies published in PubMed, PubMed Central (NCBI), Google by using following keywords: cervical cancer, cervical carcinoma, Methylation, by the end of January, 2018. The association between DAPK promoter methylation and cervical cancer was evaluated by odds ratio (ORs) and 95% confidence intervals (CI). To evaluate the potential sources of heterogeneity, the meta-regression analysis and subgroup analysis were conducted.&#x0D; Results: A total of 21 case-control studies which relevant to the association between DAPK1 gene’s promoter methylation frequency and cervical cancer, that including 1600 cancer cases and 1011 control cases (non-cancerous cases). The analysis results indicated that the characteristic of candidate gene’s promoter methylation increased the cervical cancer risk through the calculation of OR value (OR = 21.25; 95% CI = 8.73 – 52.97; p &lt; 0.001; Random effect model). The association between DAPK1 gene’s promoter hypermethylation was confirmed in all the subgroups analyses, including materials and assays methods, ethnicity. Furthermore, this association is higher in cervical squamous cell carcinoma than cervical adenocarcinoma and is a characteristic of late-stage disease.&#x0D; Conclusion: The hypermethylated DAPK1 gene’s promoter was also one of etiological factor, lead to the cervical tumorigenesis.

Analysis of Promoter Hypermethylation of DAPK and BAX Apoptotic Genes in Iranian Gastric Cancer Patients Undergoing Chemotherapy

Background: The apoptotic route is mostly damaged in gastric cancer tumor cells. DNA methylation of promoter associated CpG islands inactivates tumor suppressor genes. The objective of the present study was to analyze the hypermethylation of death-associated protein kinase (DAPK) and Bcl-2-associated X protein (BAX) genes in individuals suffering from gastric cancer and undergoing chemotherapy. Methods: Genomic DNA was extracted from blood samples and the tissue fixed in the paraffin of 30 patients and normal individuals. Hypermethylation investigation of DAPK and BAX genes was conducted via methylation specific PCR technique, the outcomes of which were analyzed through electrophoresis and SPSS software version 20. Results: Methylation of both BAX and DAPK genes with a frequency of (28.3%, 21.7%) in blood and (23.3%, 23.3%) in tissue, respectively, had a significant relationship with gastric cancer (P˂0.01). A significant relationship was also observed between the methylation of BAX gene in tissue and tumor type (12, 35.3% and P˂0.01). No relationship was found between methylation and grade, stage, node, age, sex, and other pathologic and clinical data of the patients (P>0.05). There was a significant association between simultaneous methylation of DAPK and BAX genes in tumor and typical tissues with methylation a frequency of 40% and 95.83%, respectively (P˂ 0.01). Conclusion: Methylation of the BAX and DAPK genes can be used as a biomarker in bloodand an approach in the early detection of malignity and illness management. Methylation inhibitors with the potential for drug targeting of DAPK and BAX can further be employed in pharmacotherapy.

Clinicopathological significance of DAPK promoter methylation in non-small-cell lung cancer: a systematic review and meta-analysis.

BackgroundLung carcinogenesis is related to silencing of tumor suppressor genes and activation of oncogenes. The aim was to investigate the significance of death-associated protein kinase (DAPK) methylation in non-small-cell lung cancer (NSCLC) through a meta-analysis.MethodsA detailed literature search was made in PubMed, Embase, and Web of Science databases. All analysis was performed with Review Manager 5.2.ResultsIn total, 28 studies with a total of 2,148 patients were involved. The frequency of DAPK promoter hypermethylation was 40.50% in NSCLC, significantly higher than in nonmalignant lung tissue; the pooled OR was 5.69, P<0.00001. Additionally, DAPK promoter hypermethylation was significantly correlated with poor overall survival in patients with NSCLC. However, there was no significant difference found while comparing the rate of DAPK promoter hypermethylation in adenocarcinoma and squamous cell cancer. The rate of DAPK promoter hypermethylation was similar between stage III/IV and stage I/II. In addition, the data showed that DAPK promoter hypermethylation was not associated with smoking behavior in patients with NSCLC.ConclusionDAPK promoter hypermethylation is correlated with risk of NSCLC and is a potential biomarker for prediction of poor prognosis in patients with NSCLC.

Differential Hypermethylation of Death-Associated Protein Kinase Promoter in Central Neurocytoma and Oligodendroglioma

Background. Central neurocytoma and oligodendroglioma are rare tumors of the central nervous system. However, diagnosis between these two types of tumors is challenging due to their many cytological and histological similarities. Death-associated protein kinase (DAPK) is a calcium/calmodulin-regulated serine/threonine protein kinase involved in many apoptosis pathways, and repressed expression of DAPK by promoter hypermethylation has been found in a variety of human cancers. The purpose of this study was to assess DAPK protein expression and promoter hypermethylation in central neurocytoma and oligodendroglioma. Method. Central neurocytoma and oligodendroglioma samples were obtained from age- and sex-matched patients. DAPK protein expression was performed using immunohistochemical assays in formalin-fixed, paraffin-embedded sections. DAPK promoter hypermethylation was carried out using bisulfite-modified genomic DNA in methylation-specific PCR followed by separation in agarose gels. Findings. A statistically significant difference (P = 0.021) in DAPK promoter hypermethylation between central neurocytoma (76.9%) and oligodendroglioma (20%) was observed. High levels of DAPK protein expression were generally found in oligodendroglioma (90%), compared with 38.5% in central neurocytoma (P = 0.054; not statistically significant). There was an inverse correlation between DAPK protein expression and DAPK promoter hypermethylation in the cohort of 23 patients (P = 0.002). Conclusions. The results show that DAPK promoter hypermethylation and repressed expression of DAPK protein were more common in central neurocytoma than in oligodendroglioma. Thus, DAPK promoter hypermethylation could be useful for differential diagnosis between these two types of tumors, whereas DAPK protein expression might be less predictive. The role of DAPK promoter hypermethylation in the pathogenesis of central neurocytoma warrants further study.

Promoter hypermethylation patterns of P16, DAPK and MGMT in oral squamous cell carcinoma: a systematic review and meta-analysis.

Oral squamous cell carcinoma (OSCC) is a common cancer world-wide that is highly lethal due to its recurrence and metastasis. Methylation is a common epigenetic mechanism that leads to gene silencing in tumors and could be a useful biomarker in OSCC. The prevalence of P16, death-associated protein kinase (DAPK) and O6-methylguanine-DNA-methyltransferase (MGMT) promoter hypermethylation in OSCC has been evaluated for several years while the results remain controversial. The aim of this systematic review is to critically analyze and perform a meta-analysis on the various studies in the literature that have reported the promoter hypermethylation of P16, DAPK and MGMT genes in OSCC. Articles were searched and selected through PubMed. Hand search from the relevant journals was also performed. Articles were reviewed and analyzed. The estimated prevalence of P16 methylation was 43%, DAPK methylation was 39.7% and MGMT methylation was 39.8%. Heterogeneity in methylation prevalences and correlations with the clinical outcomes of the disease prevailed in various studies. We can conclude from our systematic review that a higher prevalence of methylation of P16, DAPK and MGMT occur in OSCC. Further studies are required to substantiate the role of methylation of P16, DAPK and MGMT as a marker in OSCC.

MRNA expression and hypermethylation of tumor suppressor genes apoptosis protease activating factor-1 and death-associated protein kinase in oral squamous cell carcinoma

Apoptosis protease activating factor-1 (Apaf-1) and death-associated protein kinase (DAPK) are p53 pathway-related genes that play significant roles in the activation of caspases, which are involved in mitochondrial-mediated apoptosis. The present study aimed to confirm the role of hyper-methylation of the Apaf-1 and DAPK gene promoter regions in oral squamous cell carcinoma (OSCC) and the effect of the demethylation drug, 5-aza-2′-deoxycytidine (DAC). mRNA from 53 OSCC samples, 23 normal oral mucosa samples and Tca8113 human tongue carcinoma cell lines was detected using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The DNA from each sample was analyzed using methylation-specific PCR (MSP). The Tca8113 cells were demethylated using DAC and the demethylation and re-expression of Apaf-1 and DAPK were analyzed. The Apaf-1 and DAPK mRNA expression index was decreased in 51 (96.23%) and 50 (94.34%) cases, respectively, in the tumor tissues. Hypermethylation of the Apaf-1 and DAPK promoter regions was detected in 46 (86.79%) and 38 (71.69%) cases, respectively. Promoter hypermethylation of the two genes correlated with a decreased mRNA expression in the tumor tissues. Subsequent to being treated with DAC, Apaf-1 and DAPK were demethylated and re-expressed in the Tca8113 cells. Apaf-1 and DAPK promoter hypermethylation may be associated with low gene expression in OSCC. Furthermore, a loss of Apaf-1 and DAPK expression may recover following demethylation. The data provide evidence that methylation exists in OSCC and may play a role in the development of this disease.

Promoter Hypermethylation of Death-Associated Protein Kinase and p16 Genes in Vulvar Lichen Sclerosus

The purpose of this study was to discuss our investigation of the hypermethylation of promoter regions of tumor suppressor genes, such as death-associated protein kinase (DAPK) and p16, in vulvar lichen sclerosus (LS), in comparison with a control group. Promoter hypermethylation of DAPK and p16 was investigated using 24 vulvar biopsies of patients with LS who had received no previous treatment. The control group was composed of 15 patients with no vulvar disease. The DNA of subjects was treated with sodium bisulphate, and the genes under study were subjected to methylation-specific polymerase chain reaction. The resulting polymerase chain reaction products were amplified and analyzed using a 10% polyacrylamide gel. The mean age of the patients with LS was 57 years (the majority were postmenopausal). In the control group, the mean age of the patients was 50 years (p = .151). Methylation of the promoter region of DAPK was found in 4 (17%) of the 23 patients analyzed, and p16 promoter region methylation was found in 8 patients (35%). Two cases of methylation of the DAPK gene were also found to be methylated for the p16 gene. In the control group, no methylation was found in the patients analyzed for the DAPK gene and methylation was found in 3 (21%) of the 14 patients analyzed for the p16 gene (p = .190 and p = .316, respectively). Methylation of the DAPK and p16 genes, although not sufficient to dictate prognosis of the disease, should not be underestimated because it may form part of a process of genetic and epigenetic alterations that in the future could become relevant to malignant transformation.

Hypermethylation of MGMT and DAPK gene promoters is associated with tumorigenesis and metastasis in oral squamous cell carcinoma

Background/purpose Oral squamous cell carcinoma (OSCC) is the fourth major cause of mortality among males in Asia. The tumorigenesis of OSCC is a multi-step process characterized by sequential morphological changes. The extent of lymph node metastasis is a major determinant in the prognosis of cancer. Hypermethylation is an important pathway for repression of gene transcription in cancer cells and a promising marker for cancer detection. It is also found in early metastatic cancer patients. Materials and methods Sixty-four histologically confirmed OSCC tissues and corresponding nontumorous tissues were enrolled in this study. DNA was extracted. The promoter methylation status of the p16, death-associated protein kinase (DAPK), MGMT, and glutathione S-transferase genes in OSCC tissues was evaluated by a methylation-specific polymerase chain reaction analysis. Results Frequencies of promoter hypermethylation of p16, DAPK, and MGMT in OSCC tissue were 67.2%, 45.3%, and 31.3%, respectively. No methylation was found in normal oral mucosa. Methylation rates of MGMT (50%) and DAPK (55.6%) in metastasized OSCC were higher than those of MGMT (23.9%) and DAPK (41.3%) in nonmetastasized OSCC. No glutathione S-transferase P methylation was found in any tissue samples. Conclusions Our study supports the hypothesis that hypermethylation of p16 gene promoters may indicate a high risk of oral cancer, and hypermethylation of the MGMT and DAPK genes may be a major indicator of early OSCC metastasis.

DAPK promoter hypermethylation in tissues and body fluids of oral precancer patients

Death-associated protein kinase (DAPK) has been suggested as a tumor suppressor gene. A high frequency of DAPK promoter hypermethylation has been noted in head and neck cancers and other solid tumors, and it has been used as a tumor marker in molecular detection strategies. Our aim was to examine DAPK promoter hypermethylation in tissue, blood, and salivary rinse samples of oral precancer patients (OPs) and to explore the potential role in oral carcinogenesis. DAPK hypermethylation was analyzed in 77 OPs and 32 oral squamous cell carcinomas (OSCCs) by real-time quantitative methylation-specific PCR (QMSP). We compared the hypermethylation expression between two groups and analyzed the associations with clinicopathologic parameters. The promoter hypermethylation frequency of DAPK in tissue (46.9%) and blood (52.2%) of OSCCs was significantly higher than those in OPs (19.5%, P = 0.004; 22.4%, P = 0.007, respectively). DAPK promoter hypermethylation expression in blood was correlated with its expression in tissue (r = 0.49, P < 0.000). The OP patients who smoked more than 20 years were found 40.0% tissue DAPK hypermethylation in contrast with 10.7% tissue DAPK hypermethylation in the patients whose smoking duration ≦20 years (P = 0.010). Our results suggest that DAPK hypermethylation is an early event in oral carcinogenesis and blood DAPK hypermethylation might be a potential minimal invasive biomarker for OSCC early detection.

Promoter Hypermethylation Patterns of Death-Associated Protein Kinase and p16 Genes in Vulvar Lichen Sclerosus

This article aimed to investigate the hypermethylation of promoter regions of tumor suppressor genes, such as death-associated protein kinase (DAPK) and p16, in vulvar lichen sclerosus (LS). The promoter hypermethylation of DAPK and p16 was investigated from 15 vulvar biopsies of patients with LS who had had no previous treatment. DNA was treated with sodium bisulfate and underwent methylation-specific polymerase chain reaction of these genes. The amplified polymerase chain reaction products were analyzed by 10% polyacrylamide gel. The mean age of the patients was 57 years (most were postmenopausal). Methylation of the promoter region of DAPK was found in 2 (13%) of 15 patients analyzed, and p16 promoter region methylation was found in 7 patients (47%). The samples that showed DAPK methylation also showed p16 methylation. Methylation of DAPK and p16 represent alterations that might occur in cell cycle control in LS. The hypothesis is that patients who had methylated genes in this study, mainly the 2 cases in which there has been methylation in both studied genes, may be more susceptible to the development of differentiated vulvar intraepithelial neoplasia or vulvar cancer. Methylation may play a role in progress of vulvar carcinogenesis.

Aberrant methylation of DAPK in long-standing ulcerative colitis and ulcerative colitis-associated carcinoma

Death-associated protein kinase (DAPK) has pro-apoptotic functions and participates in various apoptotic systems. DAPK acts as a tumor suppressor, and its inactivation by promoter hypermethylation has been frequently observed in various human cancers. As alterations of pro-apoptotic genes might cause instability in the balance of cell-turnover during chronic inflammatory processes, epigenetic silencing of DAPK might be involved in the carcinogenesis of ulcerative colitis-associated carcinoma (UCC). To evaluate the role of DAPK in the inflammation-driven carcinogenesis of ulcerative colitis (UC), we analyzed promoter hypermethylation and protein expression of DAPK using methylation-specific PCR and immunohistochemistry in 43 UCCs and paired UC-background mucosa, as well as in UC-background mucosa of 50 patients without UCC. The frequency of methylation of DAPK in UCCs was low (27.6%) compared to overall non-neoplastic UC-background mucosa (48.3%; p = 0.02) and sporadic colorectal carcinoma (57.4%, p = 0.019). The difference in the methylation frequency in UC-background mucosa in patients without UCC (54.2%), compared to those with UCC (40.0%), was not significant ( p = 0.141). Promoter methylation correlated significantly with decreased DAPK protein expression ( p < 0.001) and severity of inflammatory activity ( p = 0.024). In unmethylated UC-background mucosa, DAPK protein expression increased with activity of UC-associated inflammation, suggesting a protective role of the pro-apoptotic DAPK during the chronic inflammatory process of UC. Thus, inactivation of DAPK by promoter hypermethylation might be crucial for accumulation of DNA damage in inflamed mucosa of UC, and might therefore contribute to the initiation of the neoplastic process and development of UC-associated carcinoma.

Prognostic significance of DAPK and RASSF1A promoter hypermethylation in non-small cell lung cancer (NSCLC).

The epigenetic inactivation of tumor suppressor genes may play an important role in the development and progression of many cancer types, including lung cancer. Therefore, we investigated the association between the aberrant promoter methylation of 2 genes: the Death-Associated Protein Kinase (DAPK) and the Ras Association Domain Family 1A (RASSF1A) by using methylation-specific PCR, and the clinicopathological features and prognosis in 70 radically resected non-small cell lung cancers (NSCLCs). Hypermethylation of the DAPK and RASSF1A promoters was found in 24 (34%), and in 18 (26%) tumor DNA samples, respectively. Regarding different clinicopathological features of NSCLCs, the DAPK promoter methylation was more frequently observed in squamous cell carcinoma (46%) than in adenocarcinoma (25%) and large cell carcinoma (22%), but there were no significant statistical differences (p=0.3). On the other hand, a statistically significant trend was observed between the RASSF1A methylation and a histological type of tumor (p=0.06). 45% of adenocarcinoma tumors showed RASSF1A promoter methylation in comparison to 17% of squamous cell carcinomas and 22% of large cell carcinomas. When both markers were analyzed according to the tumor-node-metastasis (TNM) staging system, no statistically significant differences were observed between stage I, II and IIIa, and the DAPK (p=0.2) and RASSF1A methylation (p=0.1). In comparison, when stage I and II were grouped together and considered vs. stage IIIa, a significant association between RASSF1A methylation and the TNM was found (p=0.03). The group of patients with tumors showing DAPK promoter methylation had significantly poorer overall survival rates (p=0.02) than the patients with tumors that did not show DAPK promoter methylation. However, the association between the RASSF1A promoter methylation status and the overall survival rates was not statistically significant (p=0.48). In conclusion, this paper supports the importance of epigenetic gene regulation in lung cancer progression and prognosis.

Sodium arsenite-induced DAPK promoter hypermethylation and autophagy via ERK1/2 phosphorylation in human uroepithelial cells

Arsenic compounds or arsenicals are well-known toxic and carcinogenic agents. The toxic effects of arsenic that are of most concern to humans are those that occur from chronic, low-level exposure, and are associated with various human malignancies, including skin, lung and bladder cancers. In addition, arsenic could induce cell death, including apoptosis or autophagy in malignant cells. Previously, we have demonstrated that arsenite can induce autophagy and death-associated protein kinase (DAPK) promoter hypermethylation in the SV-40 immortalized human uroepithelial cell line (SV-HUC-1). However, the underlying mechanism of arsenite-induced autophagy is still unclear. In the present study, we demonstrate that arsenite can activate the extracellular signaling-regulated protein kinase 1/2 (ERK1/2) signaling pathway after treatment in SV-HUC-1 cells by using immunocytochemistry and Western blotting. In addition, our results also show an increase of autophagosomes was produced in arsenite-treated SV-HUC-1 cells by using electron microscopy. We found that, by incrementally increasing the dosages, microtubule-associated protein light chain 3B (LC3B) and Beclin-1 are important regulators for the formation of autophagosomes, in a dose-dependent manner. When the cells were pretreated with inhibitors 5-aza-CdR or U0126 for 24 h, the effect of arsenite on ERK1/2, LC3B, Beclin-1 and DAPK proteins expression is suppressed. Furthermore, our results support the notion that arsenite can induce the ERK1/2 signaling pathway to stimulate autophagy and DAPK promoter hypermethylation in human uroepithelial SV-HUC-1 cells. These findings may contribute to a better understanding of the carcinogenesis of arsenite.

Correlation of promoter hypermethylation in hTERT, DAPK and MGMT genes with cervical oncogenesis progression

DNA hypermethylation occurs during the multistep process of cervical carcinogenesis. We investigated whether the methylation status in the promoter region of a potential oncogene, the human telomerase reverse transcriptase (hTERT), and the tumor suppressor genes death-associated protein kinase (DAPK) and O6-methylguanine DNA methyltransferase (MGMT), were able to distinguish the early from late stages of cervical oncogenesis. The methylation status in the promoter of these genes was analyzed using real-time MethyLight analysis in 115 cervical specimens, including normal, premalignant [atypical squamous epithelial cells (ASCUS), low-grade squamous intraepithelial lesions (LGSIL), high-grade squamous intraepithelial lesions (HGSIL)] and cancer specimens. Clinicopathological parameters (cytology, histology, grade, stage) were compared to the levels of promoter hypermethylation. We found that hTERT, MGMT and DAPK hypermethylation levels were increased during cervical oncogenesis progression. hTERT promoter hypermethylation was able to distinguish normal from cancer (p=0.008), normal from premalignant (p=0.036), as well as premalignant from cervical cancer cases (p=0.003). A significant association was also observed between all three genes and the grade of cervical cancer, with hTERT showing a better association (p<0.0001). Our data suggest that the combination of hTERT, MGMT, DAPK promoter hypermethylation could have a potential function as molecular biomarker of cervical oncogenesis progression.

Urothelial carcinomas arising in arsenic‐contaminated areas are associated with hypermethylation of the gene promoter of the death‐associated protein kinase

The mechanisms of urothelial carcinogenesis in areas highly contaminated with arsenic remain unclear. The aim was to determine whether hypermethylation of death-associated protein kinase (DAPK) gene is associated with chronic arsenic exposure. The frequency of aberrant promoter methylation of DAPK in 17 urothelial carcinomas from an arsenic-contaminated area and 21 urothelial carcinomas from a non-arsenic-contaminated area was determined by methylation-specific polymerase chain reaction. DAPK hypermethylation status was significantly higher in urothelial cancers arising in arsenic-contaminated areas when compared with tumours from patients from non-contaminated areas (P = 0.018). In the subset of patients from living environments which were contaminated with arsenic, there was a statistically significant association between DAPK hypermethylation and patient's age, tumour invasiveness, histological grade and recurrence. This was not seen for urothelial carcinoma from patients from non-contaminated areas. A close correlation was also found between DAPK promoter methylation and low-intensity DAPK expression, as detected by immunohistochemistry (P = 0.037). Exposure to arsenic may induce DAPK promoter hypermethylation and inactivate the function of DAPK in urothelial carcinoma. This could prove to be a key molecular event contributing to the malignant phenotype of tumour arising in patients from arsenic-contaminated environments.

Positive Correlation of Tissue Inhibitor of Metalloproteinase‐3 and Death‐Associated Protein Kinase Hypermethylation in Head and Neck Squamous Cell Carcinoma

Promoter hypermethylation of tumor suppressor genes is common in head and neck cancer as well as other primary cancers resulting in epigenetic gene silencing. Tissue inhibitor of metalloproteinase-3 (TIMP-3) has been shown to have promoter hypermethylation in several solid tumors, but has not been identified in head and neck squamous cell carcinoma (HNSCC). Our objective was to determine if TIMP-3 promoter was hypermethylated in HNSCC, if there was any correlation with death associated protein kinase (DAPK), a tumor suppressor whose promoter has been hypermethylated at high levels in HNSCC, and if any clinical factors influence hypermethylation of either of these genes. Prospective study. Tumor samples from 124 patients with HNSCC were evaluated for promoter hypermethylation for TIMP-3 and DAPK using quantitative methylation specific polymerase chain reaction (qMSP). We compared both TIMP-3 and DAPK hypermethylation in HNSCC with each other as well as with other clinical variables. We found that TIMP-3 was hypermethylated in approximately 71.8% of the tumor samples and DAPK was hypermethylated in 74.2%. The presence of TIMP-3 and DAPK promoter hypermethylation was significantly higher than in control specimens. More importantly, TIMP-3 and DAPK hypermethylations in these samples were highly correlated with a concordance of 78% (P < .001). DAPK was also correlated with current alcohol consumption (P < .028), but neither TIMP-3 nor DAPK hypermethylation was significantly correlated with other clinical variables or with survival. TIMP-3 promoter hypermethylation is elevated in HNSCC and is highly correlated with DAPK hypermethylation, implying a functional relationship between these genes.

Correlation between promoter hypermethylation of GSTP1 and response to chemotherapy in diffuse large B cell lymphoma

Glutathione-S-transferase P1 (GSTP1) and O6-methylguanine DNA methyltransferase (MGMT) are involved in drug-resistant to chemotherapeutic agents such as doxorubicin. In this study, prognostic significance of promoter hypermethylation and mRNA and protein expression of GSTP1 and MGMT together with promoter hypermethylation of death-associated protein kinase (DAPK) in diffuse large B cell lymphoma (DLBCL) was analyzed. Fifty-three patients with DLBCL, 24 men and 29 women, with age ranging from 23 to 91 (median 65), were analyzed. Genomic DNA and total RNA extracted from frozen samples of DLBCL were analyzed by methylation-specific polymerase chain reaction and quantitative reverse transcription polymerase chain reaction (RT-PCR) to determine promoter hypermethylation and mRNA expression of GSTP1, MGMT, and DAPK. Immunohistochemical analysis was performed to determine GSTP1 and MGMT expression at the protein level. Promoter hypermethylation of GSTP1, MGMT, and DAPK was detected in 12 (22.6%), 21 (39.6%), and 36 (67.9%) of 53 patients, respectively. Quantitative RT-PCR and immunohistochemistry did not show a correlation between methylation status and mRNA and protein expression of GSTP1 and MGMT. Patients with GSTP1 promoter hypermethylation showed a better 5-year overall survival rate than those without (100 vs 62.2%; p < 0.05). However, GSTP1 promoter hypermethylation was not an independent prognosticator in multivariate analysis. Methylation status of GSTP1 could be an indicator of drug response and a prognosticator for DLBCL.

Early Involvement of Death-Associated Protein Kinase Promoter Hypermethylation in the Carcinogenesis of Barrett's Esophageal Adenocarcinoma and Its Association with Clinical Progression

Esophageal Barrett's adenocarcinoma (BA) develops through a multistage process, which is associated with the transcriptional silencing of tumor-suppressor genes by promoter CpG island hypermethylation. In this study, we explored the promoter hypermethylation and protein expression of proapoptotic deathassociated protein kinase (DAPK) during the multistep Barrett's carcinogenesis cascade. Early BA and paired samples of premalignant lesions of 61 patients were analyzed by methylation-specific polymerase chain reaction and immunohistochemistry. For the association of clinicopathological markers and protein expression, an immunohistochemical tissue microarray analysis of 66 additional BAs of advanced tumor stages was performed. Hypermethylation of DAPK promoter was detected in 20% of normal mucosa, 50% of Barrett's metaplasia, 53% of dysplasia, and 60% of adenocarcinomas, and resulted in a marked decrease in DAPK protein expression (P < .01). The loss of DAPK protein was significantly associated with advanced depth of tumor invasion and advanced tumor stages (P < .001). Moreover, the severity of reflux esophagitis correlated significantly with the hypermethylation rate of the DAPK promoter (P < .003). Thus, we consider DAPK inactivation by promoter hypermethylation as an early event in Barrett's carcinogenesis and suggest that a decreased protein expression of DAPK likely plays a role in the development and progression of BA.

Promoter hypermethylation of TMS1 and DAPK were correlated to low chemosensitivity and poor prognosis in patients with recurrent gastric cancer

4280 Background: Promoter hypermethylation plays an important role in the inactivation of tumor suppressor genes during tumorigenesis. Gene silencing associated with aberrant methylation of promoter region CpG islands is an acquired epigenetic alteration that serves as an alternative to genetic defects in the inactivation of tumor suppressor and other genes in human cancers. Target of methylation-induced silencing (TMS1) is a novel CpG island-associated gene and induces apoptosis through activation of caspase-9 and inhibited the survival of human breast cancer cells. Methylation of the apoptosis-associated gene death-associated protein kinase (DAPK) has been recently described in stage I lung cancer, in which it portends a poor prognosis. In the present study, promoter hypermethylation of TMS1 and DAPK were investigated and in gastric cancer specimen and compared to chemosensitivity and patient’s prognosis. Methods: Methylation status of forty-one gastric cancer specimens, all of which were formalin-fixed and paraffin embedded, were studied by methylation specific PCR. All the patients were administered 5-FU based chemotherapy for the treatment of recurrent lesion. Results: Hypermethylation of TMS1 and DAPK was observed 36.7% and 37.1% of the specimen, respectively. In TMS1 (DAPK) unmethylated group, 42.3 (45.5) % of the patients responded to the chemotherapy, while 20.0 (23.1)% responded in TMS1 (DAPK) methylated group. Patients with both TMS1 and DAPK methylated cancer showed significant poor survival than the others (p=0.0452, Log-rank test). Conclusions: Promoter hypermethylation of TMS1 and DAPK were supposed to be negative predictive and prognostic factors in patients with recurrent gastric cancer, probably through preventing apoptosis. No significant financial relationships to disclose.