metallothionein and Lymphoma--Large-B-Cell--Diffuse

Diffuse Large B-cell lymphoma (DLBCL) is an aggressive disease with heterogeneous outcome and marked variable response to chemotherapy. We assessed promoter hypermethylation (PM) for a panel of tumor suppressor genes in 75 DLBCLs compared to 20 lymphoid hyperplasia (LH) and 30 normal control, using methylation specific PCR. Results were correlated to patients' clinic-pathological characteristics, immunophenotyping, and patients' outcome. DAPK1, RUNX3, MT1G, MGMT, CDH1 and p16 PM were detected in 38.7% (29/75), 49.3% (37/75), 46.7% (35/75), 44% (33/75), 49.3% (37/75) and 42.7% (32/75);respectively, of DLBCL patients compared to LH group (P < 0.05). Aberrant PM of RUNX3, MGMT, CDH1 and p16 was significantly higher in non-germinal central B-cell like (non-GCB) compared to GCB (58.3% vs. 33.3%, 56.2% vs. 22.2, 62.5% vs. 25.9, and 56.2% vs. 18.5%, respectively). PM of studies genes in DLBCL associated significantly with worse survival outcome and resistance to chemotherapy (P ≤ 0.01). In non-GCB group, DAPK1, MT1G, RUNX3, CDH1 and p16 PM associated significantly with reduced DFS (P ≤ 0.004) and OS (P ≤ 0.015). Multivariate analysis indicated that RUNX3 and CDH1 PM were independent prognostic factors for OS (P = 0.03 and 0.04; respectively), while DAPK1, RUNX3 and MT1G PM were independent prognostic factors for DFS (P = 0.002, 0.037& 0.007; respectively). DAPK1, RUNX3, MT1G, CDH1 and p16 PM are promising prognostic and/or predictive markers for non-GCB independent of IPI. Upregulation of those genes using new demethylating agents is a promising approach that sensitize chemoresistant DLBCL patients, especially the non-GCB subtype.

Topics: Adult; Aged; Antigens, CD; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cadherins; Core Binding Factor Alpha 3 Subunit; Death-Associated Protein Kinases; Disease-Free Survival; DNA Methylation; Doxorubicin; Female; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Humans; Lymphoma, Large B-Cell, Diffuse; Male; Metallothionein; Middle Aged; Prognosis; Promoter Regions, Genetic; Retrospective Studies; Survival Analysis

Abundant macrophage infiltration in tumors often correlates with a poor prognosis. T cell/histiocyte rich large B cell lymphoma (THRLBCL) is a distinct aggressive B cell lymphoma entity showing a high macrophage content. To further elucidate the role of tumor-associated macrophages in THRLBCL, we performed gene expression profiling of microdissected histiocyte subsets of THRLBCL, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), Piringer lymphadenitis, sarcoidosis, nonspecific lymphadenitis and monocytes from peripheral blood. In a supervised principal component analysis, histiocytes from THRLBCL were most closely related to epithelioid cells from NLPHL, with both types of cells expressing genes related to proinflammatory and regulatory macrophage activity. Moreover, histiocytes from THRLBCL strongly expressed metal-binding proteins like MT2A, by which histiocytes of THRLBCL can be distinguished from the other histiocyte subsets investigated. Interestingly, the validation at the protein level showed a strong expression of TXN, CXCL9, MT2A and SOD2 not only in macrophages of THRLBCL but also in the tumor cells of NLPHL and classical Hodgkin lymphoma (cHL). Overall, the present findings indicate that macrophages in the microenvironment of THRLBCL have acquired a distinct gene expression pattern that is characterized by a mixed M1/M2 phenotype and a strong expression of several metal binding proteins. The microenvironments in NLPHL and THRLBCL appear to have a similar influence on the macrophage phenotype. The high expression of metal binding proteins in histiocytes of THRLBCL may be diagnostically useful, but a potential pathophysiological role remains to be identified.

Topics: Chemokine CXCL9; Gene Expression Regulation, Neoplastic; Hodgkin Disease; Humans; Lymph Nodes; Lymphoma, Large B-Cell, Diffuse; Macrophages; Metallothionein; Neoplasm Staging; Prognosis; Superoxide Dismutase; T-Lymphocytes; Thioredoxins

Primary central nervous system lymphoma (PCNSL) in immunocompetent patients is highly malignant and has a poor prognosis. The PCNSL molecular features are reminiscent to some degree of diffuse large B-cell lymphoma (DLBCL), yet PCNSL shows unique molecular profiles and a distinct clinical behavior. This article characterizes the histopathology and expression profiles of metallothionein-I + II (MT-I + II) and their receptor megalin along with proliferation, oxidative stress, and apoptosis in PCNSL and in central nervous system (CNS) lymphomas due to relapse from DLBCL (collectively referred to as CNS lymphoma). We show for the first time that MT-I + II and megalin are significantly altered in CNS lymphoma relative to controls (reactive lymph nodes and non-lymphoma brain tissue with neuropathology). MT-I + II are secreted in the CNS and are found mainly in the lymphomatous cells, while their receptor megalin is increased in cerebral cells. This morphology likely reflects the CNS lymphoma microenvironment and molecular interactions between lymphomatous and neuronal cells.

Topics: Aged; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Brain; Cell Cycle Proteins; Cell Proliferation; Central Nervous System Neoplasms; DNA-Binding Proteins; Guanine; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Low Density Lipoprotein Receptor-Related Protein-2; Lymph Nodes; Lymphoma, Large B-Cell, Diffuse; Malondialdehyde; Metallothionein; Middle Aged; Minichromosome Maintenance Complex Component 7; Nuclear Proteins; Oxidative Stress; Tyrosine

Several clinical trials have shown gallium nitrate to be an active agent in the treatment of lymphoma. Whereas gallium is known to target cellular iron homeostasis, the basis for lymphoma cell resistance to gallium is not known. Understanding mechanisms of resistance may suggest strategies to enhance the clinical efficacy of gallium. In the present study, we used a focused DNA microarray to compare the expression of genes related to metal metabolism in gallium-resistant and gallium-sensitive lymphoma cell lines developed by us. Gallium-resistant cells were found to display a marked increase in gene expression for metallothionein-2A and the zinc transporter ZnT-1. Cells exposed to gallium nitrate displayed an increase in the binding of metal-responsive transcription factor-1 to metal response element sequences involved in the transcriptional regulation of metallothionein and ZnT-1 genes. Gallium nitrate induced metallothionein-2A and ZnT-1 expression in cells. A role for metallothionein in modulating the antineoplastic activity of gallium was confirmed by showing that the induction of metallothionein expression by zinc provided partial protection against the cytotoxicity of gallium and by showing that the level of endogenous metallothionein in lymphoma cell lines correlated with their sensitivity to gallium nitrate. Immunohistochemical staining of lymphomatous tissues revealed metallothionein protein to be variably expressed in different lymphomas. Our studies show for the first time that gallium acts on pathways related to zinc metabolism and that metal-responsive transcription factor-1 activity and metallothionein expression contribute to the development of gallium drug resistance. Furthermore, the endogenous level of metallothionein in lymphoma may be an important determinant of clinical response to gallium nitrate.

Topics: Antineoplastic Agents; Blotting, Northern; Cation Transport Proteins; Cell Proliferation; DNA-Binding Proteins; DNA, Complementary; Drug Resistance, Neoplasm; Electrophoretic Mobility Shift Assay; Gallium; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Immunoenzyme Techniques; Immunosuppressive Agents; Leukemia, Lymphoid; Lymphoma, B-Cell; Lymphoma, Large B-Cell, Diffuse; Metallothionein; Oligonucleotide Array Sequence Analysis; Transcription Factor MTF-1; Transcription Factors; Transcription, Genetic

We have investigated metallothionein (MT) I and II mRNA and protein in B-cell lymphomas with particular reference to diffuse large B-cell lymphoma (DLBCL). The mRNA profiling was performed on Affymetrix arrays and showed up-regulated MT mRNA in 15 of 48 DLBCLs, including 12 of 23 activated B-cell (ABC) and 3 of 9 type-3 lesions. In contrast, MT mRNA was low to undetectable in 16 germinal center B-cell (GCB)-type DLBCLs. Only 1 of 15 patients with up-regulated MT mRNA achieved a sustained remission, suggesting that up-regulated MT mRNA constitutes a significant risk factor for treatment failure. This was confirmed in 2 independent series, which showed significantly shorter 5-year survival in DLBCL with high versus low MT-IIa levels. By immunohistology, MT was shown to be present in both macrophages and lymphoma cells. The proportion of MT-positive macrophages did not correlate with the survival. In contrast, in 115 DLBCLs, MT labeling of more than 20% lymphoma cells was associated with a significantly poorer 5-year survival, independent of the age, stage, or International Prognostic Index. Taken together, it is suggested that both increased MT mRNA and MT protein expression by more than 20% lymphoma cells constitute independent risk factors in DLBCL.

Topics: Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Lymphoma, B-Cell; Lymphoma, Large B-Cell, Diffuse; Metallothionein; Predictive Value of Tests; Prognosis; RNA, Messenger; Survival Analysis; Treatment Failure; Up-Regulation