scholarly journals Epigenetic Effects of Benzene in Hematologic Neoplasms: The Altered Gene Expression

Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2392
Author(s):  
Giovanna Spatari ◽  
Alessandro Allegra ◽  
Mariella Carrieri ◽  
Giovanni Pioggia ◽  
Sebastiano Gangemi
Keyword(s):  
Tumor Suppressor ◽  
Cpg Islands ◽  
Hematologic Malignancies ◽  
Genetic Alterations ◽  
Dna Hypomethylation ◽  
Negative Effects ◽  
Promoter Regions ◽  
Hematological Neoplasms ◽  
Altered Gene ◽  
Hematological Tumors

Benzene carcinogenic ability has been reported, and chronic exposure to benzene can be one of the risk elements for solid cancers and hematological neoplasms. Benzene is acknowledged as a myelotoxin, and it is able to augment the risk for the onset of acute myeloid leukemia, myelodysplastic syndromes, aplastic anemia, and lymphomas. Possible mechanisms of benzene initiation of hematological tumors have been identified, as a genotoxic effect, an action on oxidative stress and inflammation and the provocation of immunosuppression. However, it is becoming evident that genetic alterations and the other causes are insufficient to fully justify several phenomena that influence the onset of hematologic malignancies. Acquired epigenetic alterations may participate with benzene leukemogenesis, as benzene may affect nuclear receptors, and provoke post-translational alterations at the protein level, thereby touching the function of regulatory proteins, comprising oncoproteins and tumor suppressor proteins. DNA hypomethylation correlates with stimulation of oncogenes, while the hypermethylation of CpG islands in promoter regions of specific tumor suppressor genes inhibits their transcription and stimulates the onset of tumors. The discovery of the systems of epigenetic induction of benzene-caused hematological tumors has allowed the possibility to operate with pharmacological interventions able of stopping or overturning the negative effects of benzene.

scholarly journals The Role of Epigenetic Alterations in Papillary Thyroid Carcinogenesis

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ogechukwu P. Eze ◽  
Lee F. Starker ◽  
Tobias Carling
Keyword(s):  
Gene Expression ◽  
Cytosine Methylation ◽  
Cpg Islands ◽  
Tumor Development ◽  
Genetic Alterations ◽  
Papillary Thyroid ◽  
Promoter Regions ◽  
Novel Technologies ◽  
Approaches To Study ◽  
Thyroid Malignancies

Papillary thyroid carcinoma (PTC) accounts for over 80% of all thyroid malignancies. The molecular pathogenesis remains incompletely clarified although activation of the RET fusion oncogenes, and RAS and BRAF oncogenes, has been well characterized. Novel technologies using genome-wide approaches to study tumor genomes and epigenomes have provided great insights into tumor development. Growing evidence shows that acquired epigenetic abnormalities participate with genetic alterations to cause altered patterns of gene expression/function. It has been established beyond doubt that promoter cytosine methylation in CpG islands, and the subsequent gene silencing, is intimately involved in cancer development. These epigenetic events very likely contribute to significant variation in gene expression profiling, phenotypic features, and biologic characteristics seen in PTC. Hypermethylation of promoter regions has also been analyzed in PTC, and most studies have focused on individual genes or a small cohort of genes implicated in tumorigenesis.

scholarly journals Hypermethylation of the p15INK4B Gene in Myelodysplastic Syndromes

Blood ◽  
1997 ◽  
Vol 90 (4) ◽  
pp. 1403-1409 ◽  
Author(s):  
Toshiki Uchida ◽  
Tomohiro Kinoshita ◽  
Hirokazu Nagai ◽  
Yohsuke Nakahara ◽  
Hidehiko Saito ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Malignant Tumors ◽  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Hematologic Malignancies ◽  
Genetic Alterations ◽  
Refractory Anemia ◽  
Aberrant Methylation ◽  
Cyclin Dependent Kinase Inhibitor

Previous studies have shown that the cyclin-dependent kinase inhibitor (CDKI) genes p15INK4B and p16INK4A are frequently inactivated by genetic alterations in many malignant tumors and that they are candidate tumor-suppressor genes. Although genetic alterations in these genes may be limited to lymphoid malignancies, it has been reported that their inactivation by aberrant methylation of 5′ CpG islands may be involved in various hematologic malignancies. In this study, we investigated the p15INK4B and p16INK4A genes to clarify their roles in the pathogenesis of myelodysplastic syndrome (MDS). Southern blotting analysis showed no gross genetic alterations in either of these genes. However, hypermethylation of the 5′ CpG island of the p15INK4B gene occurred frequently in patients with MDS (16/32 [50%]). Interestingly, the p15INK4B gene was frequently methylated in patients with high-risk MDS (refractory anemia with excess blasts [RAEB], RAEB in transformation [RAEB-t], and overt leukemia evolved from MDS; 14/18 [78%]) compared with patients with low-risk MDS (refractory anemia [RA] and refractory anemia with ring sideroblast [RARS]; 1/12 [8%]). Furthermore, methylation status of the p15INK4B gene was progressed with the development of MDS in most patients examined. In contrast, none of the MDS patients showed apparent hypermethylation of the p16INK4A gene. These results suggest that hypermethylation of the p15INK4B gene is involved in the pathogenesis of MDS and is one of the important late events during the development of MDS.

scholarly journals Hypermethylation of the p15INK4B Gene in Myelodysplastic Syndromes

Blood ◽  
1997 ◽  
Vol 90 (4) ◽  
pp. 1403-1409 ◽  
Author(s):  
Toshiki Uchida ◽  
Tomohiro Kinoshita ◽  
Hirokazu Nagai ◽  
Yohsuke Nakahara ◽  
Hidehiko Saito ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Malignant Tumors ◽  
Cpg Island ◽  
Methylation Status ◽  
Cpg Islands ◽  
Hematologic Malignancies ◽  
Genetic Alterations ◽  
Refractory Anemia ◽  
Aberrant Methylation ◽  
Cyclin Dependent Kinase Inhibitor

Abstract Previous studies have shown that the cyclin-dependent kinase inhibitor (CDKI) genes p15INK4B and p16INK4A are frequently inactivated by genetic alterations in many malignant tumors and that they are candidate tumor-suppressor genes. Although genetic alterations in these genes may be limited to lymphoid malignancies, it has been reported that their inactivation by aberrant methylation of 5′ CpG islands may be involved in various hematologic malignancies. In this study, we investigated the p15INK4B and p16INK4A genes to clarify their roles in the pathogenesis of myelodysplastic syndrome (MDS). Southern blotting analysis showed no gross genetic alterations in either of these genes. However, hypermethylation of the 5′ CpG island of the p15INK4B gene occurred frequently in patients with MDS (16/32 [50%]). Interestingly, the p15INK4B gene was frequently methylated in patients with high-risk MDS (refractory anemia with excess blasts [RAEB], RAEB in transformation [RAEB-t], and overt leukemia evolved from MDS; 14/18 [78%]) compared with patients with low-risk MDS (refractory anemia [RA] and refractory anemia with ring sideroblast [RARS]; 1/12 [8%]). Furthermore, methylation status of the p15INK4B gene was progressed with the development of MDS in most patients examined. In contrast, none of the MDS patients showed apparent hypermethylation of the p16INK4A gene. These results suggest that hypermethylation of the p15INK4B gene is involved in the pathogenesis of MDS and is one of the important late events during the development of MDS.

scholarly journals Histone Modifying Enzymes in Gynaecological Cancers

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 816
Author(s):  
Priya Ramarao-Milne ◽  
Olga Kondrashova ◽  
Sinead Barry ◽  
John D. Hooper ◽  
Jason S. Lee ◽  
...  
Keyword(s):  
Genome Instability ◽  
Cpg Islands ◽  
Gene Promoter ◽  
Driver Mutations ◽  
Promoter Regions ◽  
Post Translational Modifications ◽  
Chromatin Dynamics ◽  
Cancer Types ◽  
Histone Modifying Enzymes

Genetic and epigenetic factors contribute to the development of cancer. Epigenetic dysregulation is common in gynaecological cancers and includes altered methylation at CpG islands in gene promoter regions, global demethylation that leads to genome instability and histone modifications. Histones are a major determinant of chromosomal conformation and stability, and unlike DNA methylation, which is generally associated with gene silencing, are amenable to post-translational modifications that induce facultative chromatin regions, or condensed transcriptionally silent regions that decondense resulting in global alteration of gene expression. In comparison, other components, crucial to the manipulation of chromatin dynamics, such as histone modifying enzymes, are not as well-studied. Inhibitors targeting DNA modifying enzymes, particularly histone modifying enzymes represent a potential cancer treatment. Due to the ability of epigenetic therapies to target multiple pathways simultaneously, tumours with complex mutational landscapes affected by multiple driver mutations may be most amenable to this type of inhibitor. Interrogation of the actionable landscape of different gynaecological cancer types has revealed that some patients have biomarkers which indicate potential sensitivity to epigenetic inhibitors. In this review we describe the role of epigenetics in gynaecological cancers and highlight how it may exploited for treatment.

scholarly journals PAX5 is a tumor suppressor in mouse mutagenesis models of acute lymphoblastic leukemia

Blood ◽  
2015 ◽  
Vol 125 (23) ◽  
pp. 3609-3617 ◽  
Author(s):  
Jinjun Dang ◽  
Lei Wei ◽  
Jeroen de Ridder ◽  
Xiaoping Su ◽  
Alistair G. Rust ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Tumor Suppressor ◽  
Lymphoblastic Leukemia ◽  
Genetic Alterations ◽  
Genetic Alteration ◽  
Human Leukemia ◽  
Key Points ◽  
Leukemia Development ◽  
Common Target ◽  
Mouse Mutagenesis

Key Points Heterozygous alterations of Pax5, the most common target of genetic alteration in ALL, promote ALL in mouse mutagenesis models. Leukemia development is accompanied by the acquisition of genetic alterations commonly observed in human leukemia.

scholarly journals Promoter Methylation of RASSF1A Associates to Adult Secondary Glioblastomas and Pediatric Glioblastomas

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Jorge Muñoz ◽  
María del Mar Inda ◽  
Paula Lázcoz ◽  
Idoya Zazpe ◽  
Xing Fan ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Cell Lines ◽  
Tumor Suppressor Genes ◽  
Promoter Hypermethylation ◽  
Suppressor Genes ◽  
Primary Tumors ◽  
Specific Pcr ◽  
Inactivation Mechanism ◽  
Altered Gene ◽  
Homozygous Deletions

While allelic losses and mutations of tumor suppressor genes implicated in the etiology of astrocytoma have been widely assessed, the role of epigenetics is still a matter of study. We analyzed the frequency of promoter hypermethylation by methylation-specific PCR (MSP) in five tumor suppressor genes (PTEN, MGMT, RASSF1A, p14ARF, and p16INK4A), in astrocytoma samples and cell lines. RASSF1A was the most frequently hypermethylated gene in all grades of astrocytoma samples, in cell lines, and in adult secondary GBM. It was followed by MGMT. PTEN showed a slight methylation signal in only one GBM and one pilocytic astrocytoma, and in two cell lines; while p14ARF and p16INK4A did not show any evidence of methylation in primary tumors or cell lines. In pediatric GBM, RASSF1A was again the most frequently altered gene, followed by MGMT; PTEN, p14 and p16 showed no alterations. Lack or reduced expression of RASSF1A in cell lines was correlated with the presence of methylation. RASSF1A promoter hypermethylation might be used as a diagnostic marker for secondary GBM and pediatric GBM. Promoter hypermethylation might not be an important inactivation mechanism in other genes like PTEN, p14ARF and p16INK4A, in which other alterations (mutations, homozygous deletions) are prevalent.

scholarly journals Genetic determinants of EGFR-Driven Lung Cancer Growth and Therapeutic Response In Vivo

2020 ◽  
Author(s):  
Giorgia Foggetti ◽  
Chuan Li ◽  
Hongchen Cai ◽  
Jessica A. Hellyer ◽  
Wen-Yang Lin ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Tumor Growth ◽  
Lung Adenocarcinoma ◽  
Tumor Suppressor Gene ◽  
Suppressor Gene ◽  
Genetic Alterations ◽  
Putative Tumor Suppressor ◽  
Lung Adenocarcinomas ◽  
Gene Alterations

AbstractCancer genome sequencing has uncovered substantial complexity in the mutational landscape of tumors. Given this complexity, experimental approaches are necessary to establish the impact of combinations of genetic alterations on tumor biology and to uncover genotype-dependent effects on drug sensitivity. In lung adenocarcinoma, EGFR mutations co-occur with many putative tumor suppressor gene alterations, however the extent to which these alterations contribute to tumor growth and their response to therapy in vivo has not been explored experimentally. By integrating a novel mouse model of oncogenic EGFR-driven Trp53-deficient lung adenocarcinoma with multiplexed CRISPR–Cas9-mediated genome editing and tumor barcode sequencing, we quantified the effects of inactivation of ten putative tumor suppressor genes. Inactivation of Apc, Rb1, or Rbm10 most strongly promoted tumor growth. Unexpectedly, inactivation of Lkb1 or Setd2 – which are the strongest drivers of tumor growth in an oncogenic Kras-driven model – reduced EGFR-driven tumor growth. These results are consistent with the relative frequency of these tumor suppressor gene alterations in human EGFR- and KRAS-driven lung adenocarcinomas. Furthermore, Keap1 inactivation reduces the sensitivity of EGFR-driven Trp53-deficient tumors to the EGFR inhibitor osimertinib. Importantly, in human EGFR/TP53 mutant lung adenocarcinomas, mutations in the KEAP1 pathway correlated with decreased time on tyrosine kinase inhibitor treatment. Our study highlights how genetic alterations can have dramatically different biological consequences depending on the oncogenic context and that the fitness landscape can shift upon drug treatment.

scholarly journals Enrichment of Cxcl12 promoter with TET2: A possible link between promoter demethylation and enhanced gene expression in the absence of PARP-1

2019 ◽  
Vol 71 (3) ◽  
pp. 455-462
Author(s):  
Anja Tolic ◽  
Jovana Rajic ◽  
Marija Djordjevic ◽  
Milos Djordjevic ◽  
Svetlana Dinic ◽  
...  
Keyword(s):  
Gene Expression ◽  
Technological Development ◽  
Cpg Islands ◽  
Gene Induction ◽  
Dna Hypomethylation ◽  
Mouse Embryonic Fibroblasts ◽  
Embryonic Fibroblasts ◽  
Cxcl12 Expression ◽  
Knock Out ◽  
Parp 1

Previously, we described the link between C-X-C motif chemokine 12 (Cxcl12) gene induction and DNA hypomethylation in the absence of poly(ADP-ribose) polymerase 1 (PARP-1). We have now firmly established that demethylation is the primary cause of gene induction on the basis of Cxcl12 gene upregulation upon treatment with the demethylating agent 5-azacytidine (5-aza). Since the demethylation state of Cxcl12 is favored by PARP-1 absence, we investigated the presence of ten-eleven translocation (TET) proteins on the Cxcl12 promoter in order to corroborate the relationship between the demethylation process and increased gene expression that occurs in the absence of PARP-1. Analysis was performed on the promoter region within CpG islands of Cxcl12 from control mouse embryonic fibroblasts (NIH3T3) and PARP-1 knock-out mouse embryonic fibroblasts (PARP1-/-). The lack of PARP-1 increased the abundance of TET2 on the Cxcl12 promoter, suggesting that TET-mediated demethylation provoked by the absence of PARP-1 could account for the observed increased expression of this chemokine. Deciphering the regulation of DNA (de)methylation factors that control Cxcl12 expression may provide an additional therapeutic approach in pharmacological interventions where gene switching on or off based on targeted stimulation or inhibition is necessary. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 173020]

scholarly journals Exploring the Role of a Novel Tumor Suppressor - OSR2 in T-ALL

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 26-26
Author(s):  
Arpan A. Sinha ◽  
Pilar I. Andrade ◽  
Megan Malone-Perez ◽  
Syed T Ahmed ◽  
J. Kimble Frazer
Keyword(s):  
Transcription Factor ◽  
Tumor Suppressor ◽  
Childhood Cancer ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Expression Patterns ◽  
Tumor Biology ◽  
Transgenic Animals ◽  
Genetic Alterations ◽  
Allelic Loss

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer, representing >25% of all cancers in children 0-14 years. Despite major advancements in pediatric ALL treatment, it remains the second most lethal childhood cancer, accounting for ~25% of deaths. The two types of ALL are precursor-B, or B-ALL, and precursor-T, or T-ALL, which have distinct molecular landscapes. Of these types, T-ALL comprises about 15% and 25% of pediatric and adult cases, respectively, and is historically considered more aggressive and treatment-resistant, with an inferior prognosis. In the precision medicine era, it is imperative to identify genetic alterations and aberrant gene expression patterns, to better understand tumor biology and improve treatment outcomes by identifying new therapeutic targets. Our study investigates a novel transcription factor, odd-skipped related transcription factor 2 (OSR2), which we hypothesize is a putative T-ALL tumor suppressor. We are using a zebrafish T-ALL model expressing transgenic human MYC (hMYC) regulated by a lymphoblast-specific promoter, rag2. Prior work in zebrafish and human T-ALL found low OSR2 levels in ~95% of T-ALL. Based on this, we then used RNA-seq to analyze 10 hMYC zebrafish T-ALL, confirming low-to-absent osr2 in all 10 T-ALL relative to wild-type (WT) T cells. We further confirmed decreased osr2 expression by qRT-PCR of additional T-ALL and WT thymocytes. We hypothesized that if OSR2 suppresses T-ALL, impaired zebrafish Osr2 function might increase T-ALL incidence and shorten latency. To test this, we bred osr2-mutant fish to rag2:hMYC transgenic animals to create three genotypes: heterozygous osr2-mutant (osr2het) fish, heterozygous hMYC (hMYChet) fish, and compound-heterozygote (osr2het;hMYChet) fish. We screened these genotypes for T-ALL incidence by serial fluorescence microscopy, with T-ALL subsequently confirmed by fluorescence-based flow cytometry. By 7 months of age, we found 9/18 (50%) of double-heterozygous fish developed T-ALL, compared to 0/7 hMYChet fish (p = 0.026); osr2het fish also did not develop T-ALL. Together, our findings suggest osr2 allelic loss accelerates MYC-driven T-ALL, supporting our hypothesis that osr2 is a T-ALL tumor suppressor. Disclosures No relevant conflicts of interest to declare.

scholarly journals Epigenetic Regulation of miR-92a and TET2 and Their Association in Non-Hodgkin Lymphoma

2021 ◽  
Vol 12 ◽  
Author(s):  
Esther K. Elliott ◽  
Lloyd N. Hopkins ◽  
Robert Hensen ◽  
Heidi G. Sutherland ◽  
Larisa M. Haupt ◽  
...  
Keyword(s):  
Hodgkin Lymphoma ◽  
Cell Lines ◽  
Target Genes ◽  
Cpg Islands ◽  
Mature Mirnas ◽  
Tumour Suppressor Genes ◽  
Promoter Regions ◽  
Aberrant Expression ◽  
Non Hodgkin Lymphoma

MicroRNAs (miRNAs) are well known for their ability to regulate the expression of specific target genes through degradation or inhibition of translation of the target mRNA. In various cancers, miRNAs regulate gene expression by altering the epigenetic status of candidate genes that are implicated in various difficult to treat haematological malignancies such as non-Hodgkin lymphoma by acting as either oncogenes or tumour suppressor genes. Cellular and circulating miRNA biomarkers could also be directly utilised as disease markers for diagnosis and monitoring of non-Hodgkin lymphoma (NHL); however, the role of DNA methylation in miRNA expression regulation in NHL requires further scientific inquiry. In this study, we investigated the methylation levels of CpGs in CpG islands spanning the promoter regions of the miR-17–92 cluster host gene and the TET2 gene and correlated them with the expression levels of TET2 mRNA and miR-92a-3p and miR-92a-5p mature miRNAs in NHL cell lines, tumour samples, and the whole blood gDNA of an NHL case control cohort. Increased expression of both miR-92a-3p and miR-92a-5p and aberrant expression of TET2 was observed in NHL cell lines and tumour tissues, as well as disparate levels of dysfunctional promoter CGI methylation. Both miR-92a and TET2 may play a concerted role in NHL malignancy and disease pathogenesis.

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