Different pediatric brain tumors are associated with different gene expression profiling

Background: The up-regulation of a telomere maintenance mechanism (TMM) is a common feature of cancer cells and a hallmark of cancer. Routine methods for detecting TMMs in tumor samples are still missing, whereas telomerase targeting treatments are becoming available. In paediatric cancers, alternative lengthening of telomeres (ALT) is found in a subset of sarcomas and malignant brain tumors. ALT is a non-canonical mechanism of telomere maintenance developed by cancer cells with no-functional telomerase. Methods: To identify drivers and/or markers of ALT, we performed a differential gene expression analysis between two zebrafish models of juvenile brain tumors, that differ only for the telomere maintenance mechanism adopted by tumor cells: one is ALT while the other is telomerase-dependent. Results: Comparative analysis of gene expression identified five genes of the pre-replicative complex, ORC4, ORC6, MCM2, CDC45 and RPA3 as upregulated in ALT. We searched for a correlation between telomerase levels and expression of the pre-replicative complex genes in a cohort of paediatric brain cancers and identified a counter-correlation between telomerase expression and the genes of the pre-replicative complex. Moreover, the analysis of ALT markers in a group of 20 patients confirmed the association between ALT and increased RPA and decreased H3K9me3 localization at telomeres. Conclusions: Our study suggests that telomere maintenance mechanisms may act as a driver of telomeric DNA replication and chromatin status in brain cancers and identifies markers of ALT that could be exploited for precise prognostic and therapeutic purposes.

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Gene Expression Profiling of Brain Tumors

Expression Profiling of Human Tumors ◽

10.1385/1-59259-386-0:345 ◽

2003 ◽

pp. 345-358

Author(s):

Meena K. Tanwar ◽

Eric C. Holland

Keyword(s):

Gene Expression ◽

Brain Tumors ◽

Gene Expression Profiling ◽

Expression Profiling

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Expression of Bmi-1 in Pediatric Brain Tumors as a New Independent Prognostic Marker of Patient Survival

BioMed Research International ◽

10.1155/2013/192548 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5 ◽

Cited By ~ 7

Author(s):

Shirin Farivar ◽

Reza Zati Keikha ◽

Reza Shiari ◽

Farzaneh Jadali

Keyword(s):

Gene Expression ◽

Brain Tumors ◽

Prognostic Marker ◽

Patient Survival ◽

Insertion Site ◽

Pediatric Brain Tumors ◽

High Expression ◽

Low Grade ◽

Normal Brain ◽

Pediatric Brain

Objectives. The B-cell-specific moloney leukemia virus insertion site 1 (the Bmi-1) gene is an important member in the family of polycomb group (PcG) genes that plays an oncogenic role in several types of cancer, but it’s expression as a prognostic marker in pediatric brain tumors has not been indicated.Materials and Methods. The Bmi-1 gene expression, clinic pathological and prognostic significance in a series of pediatric brain tumors were examined by real-time PCR method in 56 pediatric brain tumors.Results. The Bmi-1 gene expression in various types of pediatric brain tumors compared to that in normal brain tissue was 4.85-fold. The relative expression varied from 8.64-fold in ependymomas to 2.89-fold in other types. Expression level in high-grade tumors compared to that in low-grade tumors was 2.5 times. In univariate survival analysis of the pediatric brain tumors, a significant association of high expression of the Bmi-1 with patient survival was demonstrated. In multivariate analysis, the Bmi-1 high expression provided significant independent prognostic factors.Conclusion. Increased expression of the Bmi-1 in pediatric brain tumors may be important in the acquisition of an aggressive phenotype. In addition, it can be used as a strong and independent molecular marker of prognosis in pediatric brain tumors.

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Custom microarray for glycobiologists: considerations for glycosyltransferase gene expression profiling

Biochemical Society Symposium ◽

10.1042/bss0690135 ◽

2002 ◽

Vol 69 ◽

pp. 135-142 ◽

Cited By ~ 12

Author(s):

Elena M. Comelli ◽

Margarida Amado ◽

Steven R. Head ◽

James C. Paulson

Keyword(s):

Gene Expression ◽

Gene Expression Profiling ◽

Expression Profiling ◽

Affymetrix Genechip ◽

Microarray Technology ◽

Gene Arrays ◽

Glycosyltransferase Gene

The development of microarray technology offers the unprecedented possibility of studying the expression of thousands of genes in one experiment. Its exploitation in the glycobiology field will eventually allow the parallel investigation of the expression of many glycosyltransferases, which will ultimately lead to an understanding of the regulation of glycoconjugate synthesis. While numerous gene arrays are available on the market, e.g. the Affymetrix GeneChip® arrays, glycosyltransferases are not adequately represented, which makes comprehensive surveys of their gene expression difficult. This chapter describes the main issues related to the establishment of a custom glycogenes array.

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