Characterization of 8p21.3 chromosomal deletions in B-cell lymphoma: TRAIL-R1 and TRAIL-R2 as candidate dosage-dependent tumor suppressor genes

Deletions of chromosome 8p are a recurrent event in B-cell non-Hodgkin lymphoma (B-NHL), suggesting the presence of a tumor suppressor gene. We have characterized these deletions using comparative genomic hybridization to microarrays, fluorescence in situ hybridization (FISH) mapping, DNA sequencing, and functional studies. A minimal deleted region (MDR) of 600 kb was defined in chromosome 8p21.3, with one mantle cell lymphoma cell line (Z138) exhibiting monoallelic deletion of 650 kb. The MDR extended from bacterial artificial chromosome (BAC) clones RP11-382J24 and RP11-109B10 and included the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor gene loci. Sequence analysis of the individual expressed genes within the MDR and DNA sequencing of the entire MDR in Z138 did not reveal any mutation. Gene expression analysis and quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) showed down-regulation of TRAIL-R1 and TRAIL-R2 receptor genes as a consistent event in B-NHL with 8p21.3 loss. Epigenetic inactivation was excluded via promoter methylation analysis. In vitro studies showed that TRAIL-induced apoptosis was dependent on TRAIL-R1 and/or -R2 dosage in most tumors. Resistance to apoptosis of cell lines with 8p21.3 deletion was reversed by restoration of TRAIL-R1 or TRAIL-R2 expression by gene transfection. Our data suggest that TRAIL-R1 and TRAIL-R2 act as dosage-dependent tumor suppressor genes whose monoallelic deletion can impair TRAIL-induced apoptosis in B-cell lymphoma

Back to the drawing board-The relationship between self-report and neuropsychological tests of cognitive flexibility in clinical cohorts: A systematic review and meta-analysis

Published online 7 April 2022Cognitive flexibility has been previously described as the ability to adjust cognitive and behavioral strategies in response to changing contextual demands. Cognitive flexibility is typically assessed via self-report questionnaires and performance on neuropsychological tests in research and clinical practice. A common assumption among researchers and clinicians is that self-report and neuropsychological tests of cognitive flexibility assess the same or similar constructs, but the extent of the relationship between these two assessment approaches in clinical cohorts remains unknown. We undertook a systematic review and meta-analysis to determine the relationship between self-report and neuropsychological tests of cognitive flexibility in clinical samples. We searched 10 databases and relevant gray literature (e.g., other databases and pearling) from inception to October 2020 and used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. Eleven articles including 405 participants satisfied our eligibility criteria. A multilevel random-effects meta-analysis revealed no relationship between self-report and neuropsychological tests of cognitive flexibility (0.01, 95% CI [-0.16 to 0.18]). Individual random-effects meta-analyses between 12 different tests pairs also found no relationship. Based on our results, it is clear that the two assessment approaches of cognitive flexibility provide independent information-they do not assess the same construct. These findings have important ramifications for future research and clinical practice-there is a need to reconsider what constructs self-report and neuropsychological tests of "cognitive flexibility" actually assess, and avoid the interchangeable use of these assessments in clinical samples.Caitlin A. Howlett, Michael A. Wewege, Carolyn Berryman, Annika Oldach, Elizabeth Jennings, Emily Moore, Emma L. Karran, Kimberley Szeto, Leander Pronk, Stephanie Miles, and G. Lorimer Mosele

Same room - different windows? A systematic review and meta-analysis of the relationship between self-report and neuropsychological tests of cognitive flexibility in healthy adults

Cognitive flexibility can be thought of as the ability to effectively adapt one's cognitive and behavioural strategies in response to changing task or environmental demands. To substantiate the common inference that self-report and neuropsychological tests of cognitive flexibility provide ‘different windows into the same room’, we undertook a systematic review and meta-analysis to determine whether self-report and neuropsychological tests of cognitive flexibility are related in healthy adults. Ten databases and relevant grey literature were searched from inception. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adhered to. Twenty-one articles satisfied our inclusion criteria. A multi-level random-effects meta-analysis revealed no relationship (0.05, 95% CI = −0.00 to 0.10). Random-effects meta-analyses raised the possibility that the Cognitive Flexibility Scale and the Trail Making Test – part B (time) may be related (0.19, 95% CI = 0.06 to 0.31). We conclude that the relationship between self-report and neuropsychological tests of cognitive flexibility is not large enough to be considered convincing evidence for the two assessment approaches sharing construct validity. These results have clear implications for assessing and interpreting cognitive flexibility research and clinical practice.Caitlin A. Howlett, Michael A. Wewege, Carolyn Berryman, Annika Oldach, Elizabeth Jennings, Emily Moore, Emma L. Karran, Kimberley Szeto, Leander Pronk, Stephanie Miles, G. Lorimer Mosele

Homozygous deletions localize novel tumor suppressor genes in B-cell lymphomas

Integrative genomic and gene-expression analyses have identified amplified oncogenes in B-cell non-Hodgkin lymphoma (B-NHL), but the capability of such technologies to localize tumor suppressor genes within homozygous deletions remains unexplored. Array-based comparative genomic hybridization (CGH) and gene-expression microarray analysis of 48 cell lines derived from patients with different B-NHLs delineated 20 homozygous deletions at 7 chromosome areas, all of which contained tumor suppressor gene targets. Further investigation revealed that only a fraction of primary biopsies presented inactivation of these genes by point mutation or intragenic deletion, but instead some of them were frequently silenced by epigenetic mechanisms. Notably, the pattern of genetic and epigenetic inactivation differed among B-NHL subtypes. Thus, the P53-inducible PIG7/LITAF was silenced by homozygous deletion in primary mediastinal B-cell lymphoma and by promoter hypermethylation in germinal center lymphoma, the proapoptotic BIM gene presented homozygous deletion in mantle cell lymphoma and promoter hypermethylation in Burkitt lymphoma, the proapoptotic BH3-only NOXA was mutated and preferentially silenced in diffuse large B-cell lymphoma, and INK4c/P18 was silenced by biallelic mutation in mantle-cell lymphoma. Our microarray strategy has identified novel candidate tumor suppressor genes inactivated by genetic and epigenetic mechanisms that substantially vary among the B-NHL subtypes

Characterization of 8p21.3 chromosomal deletions in B-cell lymphoma: TRAIL-R1 and TRAIL-R2 as candidate dosage-dependent tumor suppressor genes

Deletions of chromosome 8p are a recurrent event in B-cell non-Hodgkin lymphoma (B-NHL), suggesting the presence of a tumor suppressor gene. We have characterized these deletions using comparative genomic hybridization to microarrays, fluorescence in situ hybridization (FISH) mapping, DNA sequencing, and functional studies. A minimal deleted region (MDR) of 600 kb was defined in chromosome 8p21.3, with one mantle cell lymphoma cell line (Z138) exhibiting monoallelic deletion of 650 kb. The MDR extended from bacterial artificial chromosome (BAC) clones RP11-382J24 and RP11-109B10 and included the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor gene loci. Sequence analysis of the individual expressed genes within the MDR and DNA sequencing of the entire MDR in Z138 did not reveal any mutation. Gene expression analysis and quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) showed down-regulation of TRAIL-R1 and TRAIL-R2 receptor genes as a consistent event in B-NHL with 8p21.3 loss. Epigenetic inactivation was excluded via promoter methylation analysis. In vitro studies showed that TRAIL-induced apoptosis was dependent on TRAIL-R1 and/or -R2 dosage in most tumors. Resistance to apoptosis of cell lines with 8p21.3 deletion was reversed by restoration of TRAIL-R1 or TRAIL-R2 expression by gene transfection. Our data suggest that TRAIL-R1 and TRAIL-R2 act as dosage-dependent tumor suppressor genes whose monoallelic deletion can impair TRAIL-induced apoptosis in B-cell lymphoma