ADAM23 methylation and expression analysis in brain tumors

Causal inference of the effect of blood proteome on the risk of head and neck cancer: two-sample Mendelian randomization

Early diagnosis of head and neck cancer can improve therapeutic outcomes but remains a challenge. The blood proteome can comprise a key source of biomarkers that enable the early diagnosis and precision medicine in head and neck cancer, but blood protein biomarkers of head and neck cancer are not well delineated. Here we applied two-sample Mendelian randomization to a GWAS dataset of 1478 blood proteins and large dataset of head and neck cancer cases and controls to identify blood proteome traits associated with head and neck cancer. Multiple two-sample Mendelian randomization (MR) methods were used to assess causal effects of the exposures, including: Inverse-variance weighted (IVW), Mendelian randomization-Egger method, Weight Median method, simple mode, weight mode. Sensitivity analysis was performed by using heterogeneity test, pleiotropy test and one-by-one exclusion test. Multivariable MR analyses were performed to assess the effects of obesity, diabetes mellitus, and smoking. A significant causal association between A Disintegrin and metalloproteinase domain-containing protein 23 (ADAM23) and head and neck cancer was noted. The sensitivity analysis indicated no significant bias. Multivariate analysis showed that the effect for ADAM23 remained significant after adjusting for the indirect effects of obesity, diabetes mellitus and smoking. In sum, this study showed a significant causal role of genetically dysregulated ADAM23 protein with head and neck cancer risk. The specific mechanisms underlying the role of ADAM23 in mediating head and neck cancer risk, and its role as a potential therapeutic target and biomarker, need further investigation.

A disintegrin and metalloprotease 23 hypermethylation predicts decreased disease-free survival in low-risk breast cancer patients

A Disintegrin And Metalloprotease 23 (ADAM23), a member of the ADAM family, is involved in neuronal differentiation and cancer. ADAM23 is considered a possible tumor suppressor gene and is frequently downregulated in various types of malignancies. Its epigenetic silencing through promoter hypermethylation was observed in breast cancer (BC). In the present study, we evaluated the prognostic significance of ADAM23 promoter methylation for hematogenous spread and disease-free survival (DFS). Pyrosequencing was used to quantify ADAM23 methylation in tumors of 203 BC patients. Presence of circulating tumor cells (CTC) in their peripheral blood was detected by quantitative RT-PCR. Expression of epithelial (KRT19) or mesenchymal (epithelial-mesenchymal transition [EMT]-inducing transcription factors TWIST1, SNAI1, SLUG and ZEB1) mRNA transcripts was examined in CD45-depleted peripheral blood mononuclear cells. ADAM23 methylation was significantly lower in tumors of patients with the mesenchymal CTC (P = .006). It positively correlated with Ki-67 proliferation, especially in mesenchymal CTC-negative patients (P = .001). In low-risk patients, characterized by low Ki-67 and mesenchymal CTC absence, ADAM23 hypermethylation was an independent predictor of DFS (P = .006). Our results indicate that ADAM23 is likely involved in BC progression and dissemination of mesenchymal CTC. ADAM23 methylation has the potential to function as a novel prognostic marker and therapeutic target.

Low levels of ADAM23 expression in epithelial ovarian cancer are associated with poor survival

BACKGROUND

ADAM23, a member of the disintegrin and metalloprotease (ADAM) family, has been reported to be expressed in several types of tumours. Nevertheless, the exact role of ADAM23 in epithelial ovarian cancer (EOC) remains unclear. The aim of this study was to investigate ADAM23 expression in EOC and evaluate its clinicopathological and prognostic significance.

METHODS

Immunohistochemistry (IHC), western blot and real-time PCR (RT-PCR) were used to analyse ADAM23 expression in 133 EOC, 42 benign ovarian tumour and 35 healthy control samples. Moreover, we evaluated the expression of ADAM23 in both public database (Oncomine and Kaplan-Meier plotter). The association between ADAM23 expression and various clinicopathological parameters was analysed.

RESULTS

The levels of ADAM23 mRNA and protein expression were significantly lower in EOC tissues than in corresponding control tissues and benign ovarian tumours, verifying results from the Oncomine databases. The loss of ADAM23 expression was significantly correlated with an advanced International Federation of Gynecology and Obstetrics (FIGO) stage and lymph node metastasis. The IHC data in the EOC samples correlated with the RT-PCR data. Furthermore, patients with low ADAM23 expression had shorter progression-free survival (PFS) and overall survival (OS) than patients with high ADAM23 expression. The multivariate analysis indicated that ADAM23 was an independent predictor in patients with EOC.

CONCLUSIONS

Our results demonstrate that ADAM23 expression is likely involved in the progression of EOC and may provide potential diagnostic and prognostic information regarding EOC.

Dendritic cell expression of ADAM23 governs T cell proliferation and cytokine production through the α(v)β(3) integrin receptor

ADAM23 is a member of the brain macrophage-derived chemokine family. Structural homology of ADAM proteins suggests their function as integrin receptors. Previous studies have linked ADAM23 as a dominant contributor to brain development and cancer metastasis. The present studies now show that ADAM23 expression on DCs partially governs antigen-presentation capacities to responder CD4⁺ T cells. With the use of RNAi approaches, knockdown of ADAM23 in murine BMDCs resulted in impaired T cell activation, proliferation, and cytokine production. Knockdown did not alter the maturation profile of DCs (i.e., costimulatory molecule expression or production of proinflammatory cytokines) but markedly impaired cognate T cell responses. There was a significant decrease in antigen-specific clonal expansion coupled with a global decrease in Th cytokine production. Impaired early activation and proliferation did not alter/skew the balance of Th polarization but significantly depressed total levels of IL-2, IFN-γ, IL-4, and IL-17 cytokine production in CD4⁺ T cells primed by ADAM23 knockdown versus control DCs. Finally, neutralizing antibodies targeting the α(v)β(3) integrin receptors resulted in similar phenotypes of impaired CD4⁺ T cell responses. Taken together, these studies show a novel role of ADAM23 in governing DC antigen presentation to cognate CD4⁺ T cells.

Differential Expression of ADAM23, CDKN2A (P16), MMP14 and VIM Associated with Giant Cell Tumor of Bone

Though benign, giant cell tumor of bone (GCTB) can become aggressive and can exhibit a high mitotic rate, necrosis and rarely vascular invasion and metastasis. GCTB has unique histologic characteristics, a high rate of multinucleated cells, a variable and unpredictable growth potential and uncertain biological behavior. In this study, we sought to identify genes differentially expressed in GCTB, thus building a molecular profile of this tumor. We performed quantitative real-time polymerase chain reaction (qPCR), immunohistochemistry and analyses of methylation to identify genes that are putatively associated with GCTB. The expression of the ADAM23 and CDKN2A genes was decreased in GCTB samples compared to normal bone tissue, measured by qPCR. Additionally, a high hypermethylation frequency of the promoter regions of ADAM23 and CDKN2A in GCTB was observed. The expression of the MAP2K3, MMP14, TIMP2 and VIM genes was significantly higher in GCTB than in normal bone tissue, a fact that was confirmed by qPCR and immunohistochemistry. The set of genes identified here furthers our understanding of the molecular basis of GCTB.

Involvement of epimutations in meningioma

Epimutations are heritable and reversible cell markers, which can influence cell function going beyond the effects of DNA mutations. They result from multiple and coordinated mechanisms able to modulate gene expression. Regarding the significance of epigenetics in meningioma, few and somehow contradictory results are available, although promising information has been obtained. Here we highlight the most recent advances about the impact of DNA methylation, histone modifications, and microRNA regulation on meningioma development as well as the interplay between genetic and epigenetic alterations. Data indicate that epigenetics can help to identify novel candidate genes for the management and treatment of meningioma.

A review of epigenetic and gene expression alterations associated with intracranial meningiomas

OBJECT

A more comprehensive understanding of the epigenetic abnormalities associated with meningioma tumorigenesis, growth, and invasion may provide useful targets for molecular classification and development of targeted therapies for meningiomas.

METHODS

The authors performed a review of the current literature to identify the epigenetic modifications associated with the formation and/or progression of meningiomas.

RESULTS

Several epigenomic alterations, mainly pertaining to DNA methylation, have been associated with meningiomas. Hypermethylation of TIMP3 inactivates its tumor suppression activity while CDKN2 (p14[ARF]) and TP73 gene hypermethylation and HIST1H1c upregulation interact with the p53 regulation of cell cycle control. Other factors such as HOX, IGF, WNK2, and TGF-β epigenetic modifications allow either upregulation or downregulation of critical pathways for meningioma development, progression, and recurrence.

CONCLUSIONS

Genome-wide methylation profiling demonstrated that global hypomethylation correlates with tumor grades and severity. Identification of additional epigenetic changes, such as histone modification and higher-order chromosomal structure, may allow for a more thorough understanding of tumorigenesis and enable future individualized treatment strategies for meningiomas.

Intratumoral heterogeneity of ADAM23 promotes tumor growth and metastasis through LGI4 and nitric oxide signals

Intratumoral heterogeneity (ITH) represents an obstacle for cancer diagnosis and treatment, but little is known about its functional role in cancer progression. The A Desintegrin And Metalloproteinase 23 (ADAM23) gene is epigenetically silenced in different types of tumors, and silencing is often associated with advanced disease and metastasis. Here, we show that invasive breast tumors exhibit significant ADAM23-ITH and that this heterogeneity is critical for tumor growth and metastasis. We demonstrate that while loss of ADAM23 expression enhances invasion, it causes a severe proliferative deficiency and is not itself sufficient to trigger metastasis. Rather, we observed that, in ADAM23-heterotypic environments, ADAM23-negative cells promote tumor growth and metastasis by enhancing the proliferation and invasion of adjacent A23-positive cells through the production of LGI4 (Leucine-rich Glioma Inactivated 4) and nitric oxide (NO). Ablation of LGI4 and NO in A23-negative cells significantly attenuates A23-positive cell proliferation and invasion. Our work denotes a driving role of ADAM23-ITH during disease progression, shifting the malignant phenotype from the cellular to the tissue level. Our findings also provide insights for therapeutic intervention, enforcing the need to ascertain ITH to improve cancer diagnosis and therapy.

Dual effect of serum amyloid A on the invasiveness of glioma cells

Evidence sustains a role for the acute-phase protein serum amyloid A (SAA) in carcinogenesis and metastasis, and the protein has been suggested as a marker for tumor progression. Nevertheless, the demonstration of a direct activity of SAA on tumor cells is still incipient. We have investigated the effect of human recombinant SAA (rSAA) on two human glioma cell lines, A172 and T98G. rSAA stimulated the [(3)H]-thymidine incorporation of both lines, but had dual effects on migration and invasiveness which varied according to the cell line. In T98G, the rSAA increased migration and invasion behaviors whereas in A172 it decreased these behaviors. These findings agree with the effect triggered by rSAA on matrix metalloproteinases (MMPs) activities measured in a gelatinolytic assay. rSAA inhibited activity of both MMPs in A172 cells while increasing them in T98G cells. rSAA also affected the production of compounds present in the tumor microenvironment that orchestrate tumor progression, such as IL-8, the production of reactive oxygen species (ROS) and nitric oxide (NO). We also observed that both lines expressed all three of the isoforms of SAA: SAA1, SAA2, and SAA4. These data suggest that some tumor cells are responsive to SAA and, in these cases, SAA may have a role in cancer progression that varies according to the cell type.

The expression of ADAM23 and its correlation with promoter methylation in non-small-cell lung carcinoma

ADAM23, a member of a disintegrin and metalloprotease (ADAM) family, has been reported to be expressed in several types of tumours. The exact role of ADAM23 and the possible mechanisms in which it is involved in non-small-cell lung carcinoma (NSCLC) remains unclear. Therefore, this study was designed to explore the expression of ADAM23 and its correlation with promoter methylation in NSCLC. Immunohistochemistry and RT-PCR together with Western blotting methods were used to analyse the expression of ADAM23 in 52 cancer tissue samples and eight benign pulmonary lesions as well as four cell lines. The methylated status of ADAM23 gene was determined with methylation-specific PCR (MSP). The results of immunohistochemistry showed that the expression of ADAM23 protein was lower in NSCLC than that in corresponding normal tissues and benign pulmonary lesions (38.5%vs. 86.5% and 87.5%, P < 0.05), and decreased as NSCLC progressed. Meanwhile, methylation of ADAM23 gene was observed in 21 of 52 NSCLC tissues (40.4%), much higher than that of adjacent normal tissues (7.6%) and benign pulmonary lesions (0/8). In the cancer tissues of ADAM23-negative samples, the rate of ADAM23 gene methylation was 50.3% (17/32). ADAM23 expression and its promoter methylation were negatively associated (r = -0.328, P = 0.017). Moreover, weak expression of ADAM23 in methylated cancer cells increased after treatment with 5-aza-2'-deoxycytidine (5-Aza-2'-dC), confirming that methylation was responsible for the gene downregulation. Our results demonstrate that the expression level of ADAM23 is likely to be involved in the progression of NSCLC and its downregulation is probably correlated with promoter methylation. These findings may provide potential diagnostic and prognostic information about NSCLC.

Promoter hypermethylation of the ADAM23 gene in colorectal cancer cell lines and cancer tissues

Promoter hypermethylation of the ADAM23 gene, which is normally involved in cell-to-cell and cell-to matrix adhesion, has been reported in pancreatic, breast and brain cancer, and recently the role of this gene was examined in gastric cancer. In this study, we analyzed ADAM23 expression in colorectal cancer cell lines and examined its methylation by methylation-specific PCR (MSP) and bisulfate-modified DNA sequencing analysis. Methylated cells were treated with 5-aza-2'-deoxycytidine to restore the ADAM23 expression. We then examined ADAM23 methylation status in colorectal cancer tissues and their corresponding normal tissues. We found that ADAM23 was aberrantly silenced or expressed at very low levels in 28 of the 32 (88%) colorectal cancer cell lines. MSP analysis showed that ADAM23 was methylated in 29 of 32 (91%) colorectal cancer cell lines and attenuated expression of ADAM23 was found to be related to hypermethylation in its promoter region. Moreover, the CpG dinucleotide methylation threshold of 70-90% was found to be required for complete silencing. In addition, when some cell lines without ADAM23 expression were treated with 5-aza-2'-deoxycytidine, ADAM23 was reexpressed. In colorectal cancer tissues, the promoter region of ADAM23 was hypermethylated in 36 of 76 (47%). These results demonstrated that ADAM23 may be down-regulated by aberrant promoter hypermethylation during the progression of colorectal cancer.

(Make) stick and cut loose--disintegrin metalloproteases in development and disease

"A disintegrin and metalloprotease" (ADAM) proteases form a still growing family of about 40 type 1 transmembrane proteins. They are defined by a common modular ectodomain architecture that combines cell deadhesion/adhesion and fusion motifs (disintegrin and cysteine-rich domains), with a Zn-protease domain capped by a large prodomain. Their ectodomain thus strikingly resembles snake venom disintegrin proteases, which by combined integrin blocking and extracellular proteolysis, can cause extensive tissue damage after snake bites. A surprisingly large proportion (13 ADAMs) is exclusively expressed in the male gonads, and only a minority can be found throughout all tissues. As predicted by their amino acid sequence, a major proportion of this family has not maintained a functional protease domain, most probably rendering them into pure adhesion and/or fusion proteins. For most ADAMs, the respective key function has remained elusive. Despite their overall conserved ectodomain structure, ADAMs appear to be subdivided into those with a predominant role in direct adhesion (e.g., ADAMs 1, 2, and 3) and those mainly acting as proteases (e.g., ADAMs 10 and 17). Only for a few of them are functions of more than one domain documented (e.g., ADAM9 in cell fusion and proteolysis). Several ADAMs exist in both membrane-resident and secreted isoforms; the functional significance of this dichotomy is in most cases still unclear. Knockout phenotypes have been informative only in a few cases (ADAMs 1, 2, 10, 12, 15, 17, and 19) and are mainly related to their protease function. A common denominator of ADAM-mediated proteolysis is the ectodomain shedding of a broad spectrum of substrates, including paracrine growth factors like epidermal growth factor receptor (EGFR) ligands, cell adhesion molecules like CD44 or cadherins, and the initiation of regulated intramembrane proteolysis (RIP), whereby the transmembrane fragment of the respective substrate is further cleaved by an intramembrane cleaving protease to release an intracellular domain acting as a nuclear transcription regulator. Most ADAMs feature a significant overlap of substrate specificities, explaining why an inactivation of individual ADAMs only rarely causes major phenotypes.