Chromosome missegregation causes colon cancer by APC loss of heterozygosity.

Contains fulltext : 87269.pdf (publisher's version ) (Closed access)A longstanding hypothesis in the field of cancer biology is that aneuploidy causes cancer by promoting loss of chromosomes that contain tumor suppressor genes. By crossing aneuploidyprone Bub1 hypomorphic mice onto a heterozygous null background for p53, we provided conclusive evidence for this idea.(1) Surprisingly, the tumors that developed in this model had not just lost the chromosome 11 copy harboring wild-type p53, but had also gained an extra copy of chromosome 11 bearing the p53 null allele. Here we report that a similar chromosome-reshuffling blueprint drives colonic tumorigenesis in Bub1 hypomorphic mice that are heterozygous for Apc(Min), but now involving chromosome 18. These extended studies highlight that in order for whole chromosome instability to drive tumorigenesis, it needs to establish tumor suppressor gene loss of heterozygosity while retaining two copies of the other genes on the chromosome. Additional restrictions seem to apply to whole chromosome instability as a cancer causing mechanism, which will be discussed in this paper.1 mei 201

Cyclin B2 and p53 control proper timing of centrosome separation

Item does not contain fulltextCyclins B1 and B2 are frequently elevated in human cancers and are associated with tumour aggressiveness and poor clinical outcome; however, whether and how B-type cyclins drive tumorigenesis is unknown. Here we show that cyclin B1 and B2 transgenic mice are highly prone to tumours, including tumour types where B-type cyclins serve as prognosticators. Cyclins B1 and B2 both induce aneuploidy when overexpressed but through distinct mechanisms, with cyclin B1 inhibiting separase activation, leading to anaphase bridges, and cyclin B2 triggering aurora-A-mediated Plk1 hyperactivation, resulting in accelerated centrosome separation and lagging chromosomes. Complementary experiments revealed that cyclin B2 and p53 act antagonistically to control aurora-A-mediated centrosome splitting and accurate chromosome segregation in normal cells. These data demonstrate a causative link between B-type cyclin overexpression and tumour pathophysiology, and uncover previously unknown functions of cyclin B2 and p53 in centrosome separation that may be perturbed in many human cancers

Correction of microtubule-kinetochore attachment errors: Mechanisms and role in tumor suppression

Item does not contain fulltextDuring mitosis, cells segregate duplicated chromosomes with high fidelity in order to maintain genome stability. Proper attachment of sister kinetochores to spindle microtubules is critical for accurate chromosome segregation and is driven by complex mechanisms that promote the capture of unattached kinetochores and the resolution of erroneously attached kinetochores. Defects in these surveillance systems promote chromosome segregation and aneuploidy and can contribute to neoplastic transformation. Understanding, how, at the molecular level, accurate chromosome segregation is achieved may be crucial for our understanding of how cancer cells develop genome instability

Singling Out Chromosome Gains in Tumor Evolution

Contains fulltext : 174444.pdf (publisher's version ) (Closed access)In this issue of Cancer Cell, Sheltzer et al. shed new light on Theodor Boveri's century-old hypothesis by demonstrating that aneuploidy characterized by single-chromosome gains acts to suppress tumorigenesis and that aneuploidy itself is a nidus for genomic instability

Aneuploidy in Cancer and Aging

Contains fulltext : 171360.pdf (publisher's version ) (Open Access)Chromosomal instability (CIN), the persistent inability of a cell to faithfully segregate its genome, is a feature of many cancer cells. It stands to reason that CIN enables the acquisition of multiple cancer hallmarks; however, there is a growing body of evidence suggesting that CIN impairs cellular fitness and prevents neoplastic transformation. Here, we suggest a new perspective to reconcile this apparent paradox and share an unexpected link between aneuploidy and aging that was discovered through attempts to investigate the CIN-cancer relationship. Additionally, we provide a comprehensive overview of the function and regulation of the anaphase-promoting complex, an E3 ubiquitin ligase that mediates high-fidelity chromosome segregation, and describe the mechanisms that lead to whole-chromosome gain or loss. With this review, we aim to expand our understanding of the role of CIN in cancer and aging with the long-term objective of harnessing this information for the advancement of patient care

Sgo1 as a "guardian spirit" for preventing colon tumorigenesis.

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CREB binding protein is required for both short-term and long-term memory formation.

Contains fulltext : 88296.pdf (publisher's version ) (Open Access)CREB binding protein (CBP) is a transcriptional coactivator with histone acetyltransferase activity. Our prior study suggested that CBP might be a key target of presenilins in the regulation of memory formation and neuronal survival. To elucidate the role of CBP in the adult brain, we generated conditional knock-out (cKO) mice in which CBP is completely inactivated in excitatory neurons of the postnatal forebrain. Histological analysis revealed normal neuronal morphology and absence of age-dependent neuronal degeneration in the CBP cKO cerebral cortex. CBP cKO mice exhibited robust impairment in the formation of spatial, associative, and object-recognition memory. In addition to impaired long-term memory, CBP cKO mice also displayed deficits in short-term associative and object-recognition memory. Administration of a histone deacetylase inhibitor, trichostatin A, rescued the reduction of acetylated histones in the CBP cKO cortex but failed to rescue either short- or long-term memory deficits, suggesting that the memory impairment may not be caused by general reduction of histone acetyltransferase activity in CBP cKO mice. Further microarray and Western analysis showed decreased expression of calcium-calmodulin-dependent kinase isoforms and NMDA and AMPA receptor subunits in the cerebral cortex of CBP cKO mice. Collectively, these findings suggest a crucial role for CBP in the formation of both short- and long-term memory

Senescent cells: a therapeutic target for cardiovascular disease

Contains fulltext : 196267.pdf (publisher's version ) (Open Access)Cellular senescence, a major tumor-suppressive cell fate, has emerged from humble beginnings as an in vitro phenomenon into recognition as a fundamental mechanism of aging. In the process, senescent cells have attracted attention as a therapeutic target for age-related diseases, including cardiovascular disease (CVD), the leading cause of morbidity and mortality in the elderly. Given the aging global population and the inadequacy of current medical management, attenuating the health care burden of CVD would be transformative to clinical practice. Here, we review the evidence that cellular senescence drives CVD in a bimodal fashion by both priming the aged cardiovascular system for disease and driving established disease forward. Hence, the growing field of senotherapy (neutralizing senescent cells for therapeutic benefit) is poised to contribute to both prevention and treatment of CVD

The Nucleoporin Can/Nup214 Binds to Both the Cytoplasmic and the Nucleoplasmic Sides of the Nuclear Pore Complex in Overexpressing Cells

Contains fulltext : 24997___.PDF (publisher's version ) (Open Access