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Supplementary Figures S1-S2 from Loss of p53 and MCT-1 Overexpression Synergistically Promote Chromosome Instability and Tumorigenicity

MCT-1 oncoprotein accelerates p53 degradation by means of the ubiquitin-dependent proteolysis. Our present data show that induction of MCT-1 increases chromosomal translocations and deregulated G2-M checkpoint in response to chemotherapeutic genotoxin. Remarkably, increases in chromosome copy number, multinucleation, and cytokinesis failure are also promoted while MCT-1 is induced in p53-deficient cells. In such a circumstance, the Ras–mitogen-activated protein kinase/extracellular signal-regulated kinase kinase–mitogen-activated protein kinase signaling activity and the expression of metastatic molecules are amplified. Given a p53-silencing background, MCT-1 malignantly transforms normal breast epithelial cells that are satisfactory for stimulating cell migration/adhesion and tumorigenesis. Detailed analyses of MCT-1 oncogenicity in H1299 p53-null lung cancer cells have shown that ectopically expressed MCT-1 advances xenograft tumorigenicity and angiogenesis, which cannot be completely suppressed by induction of p53. MCT-1 counteracts mutually with p53 at transcriptional levels. Clinical validations confirm that MCT-1 mRNA levels are differentially enriched in comparison between human lung cancer and nontumorigenic tissues. The levels of p53 mRNA are comparatively reduced in a subset of cancer specimens, which highly present MCT-1 mRNA. Our results indicate that synergistic promotions of chromosomal imbalances and oncogenic potency as a result of MCT-1 expression and p53 loss play important roles in tumor development. (Mol Cancer Res 2009;7(4):536–48)

Objectives Rheumatoid Arthritis (RA) is associated with polymorphism in major histocompatibility complex class II genes and dysregulations of CD4+ T cells which cause abnormalities in immune repertoire (iR) expression and intracellular signaling. We monitored nucleotide sequence changes in iR of immunoglobulin heavy chain (IGH), particularly complementarity determining region 3 (CDR3) during the course of treatments in RA patients using massively parallel sequencing technology.Methods CDR3 sequencing was carried out on clinical blood samples from RA patients for disease progress monitoring. The iR of each sample was measured using next generation sequencing (NGS) pipeline. Data analysis was done with a web-based iRweb server. Principal components analysis (PCA) was completed with commercial statistical pipeline. Results Datasets from 14 patients covered VDJ regions of IGH gene. D50 stayed low for all cases (mean D50 = 6.5). A pattern of shared CDR3 sequences was confirmed by a clustering pattern using PCA. Shared profile of 608 CDR3 sequences unique to the disease baseline was identified. D50 analyses revealed clonal diversity would remain low throughout the disease course even after treatment (mean D50 = 11.7 & 8.2 for csDMARD & bDMARD groups respectively) regardless of fluctuated disease activity. PCA has provided a correlation of change in immune diversity along the whole course of RA. Conclusion We have successfully constructed the experimental design, data acquisition, processing, and analysis pipeline of a high throughput massively parallel CDR3 sequences detection to be used to correlate RA disease activity and IGH CDR3 iR during disease progression with or without treatments.

MCT-1 oncoprotein accelerates p53 degradation by means of the ubiquitin-dependent proteolysis. Our present data show that induction of MCT-1 increases chromosomal translocations and deregulated G2-M checkpoint in response to chemotherapeutic genotoxin. Remarkably, increases in chromosome copy number, multinucleation, and cytokinesis failure are also promoted while MCT-1 is induced in p53-deficient cells. In such a circumstance, the Ras–mitogen-activated protein kinase/extracellular signal-regulated kinase kinase–mitogen-activated protein kinase signaling activity and the expression of metastatic molecules are amplified. Given a p53-silencing background, MCT-1 malignantly transforms normal breast epithelial cells that are satisfactory for stimulating cell migration/adhesion and tumorigenesis. Detailed analyses of MCT-1 oncogenicity in H1299 p53-null lung cancer cells have shown that ectopically expressed MCT-1 advances xenograft tumorigenicity and angiogenesis, which cannot be completely suppressed by induction of p53. MCT-1 counteracts mutually with p53 at transcriptional levels. Clinical validations confirm that MCT-1 mRNA levels are differentially enriched in comparison between human lung cancer and nontumorigenic tissues. The levels of p53 mRNA are comparatively reduced in a subset of cancer specimens, which highly present MCT-1 mRNA. Our results indicate that synergistic promotions of chromosomal imbalances and oncogenic potency as a result of MCT-1 expression and p53 loss play important roles in tumor development. (Mol Cancer Res 2009;7(4):536–48)

5,5′-Bis-trifluoromethyl-2,2′-dichlorobiphenyl (5,5′CF 3 -2,2′PCB) is representative of a unique class of trifluoromethyl polychlorinated biphenyls (CF 3 -PCBs) found in sediments and fish of Lake Ontario, the Niagara river, and their tributaries. The potential hazard of 5,5′CF 3 -2,2′PCB was assessed by exposing male Wistar rats to this agent in corn oil at a dose of 1 mg/kg/day or 75 mg/kg/day or corn oil alone (control) by oral intubation for 7 consecutive days. No lethality occurred during the course of exposure. A significant increase in liver weight and liver/body weight ratio and significant decrease in body weight gain were observed following exposure to the high dose of CF 3 -PCB, relative to control. Exposure to the CF 3 -PCB also resulted in a dose-related increase in the total hepatic cytochrome P450 content. This was associated with a dose-related increase in the O-deethylation of ethoxycoumarin, an activity which is mediated by several cytochrome P450s and thus provides a general representation of cytochrome P450 status. Specifically, a dose-dependent induction of the cytochrome P450s 1A1 and 1A2 (CYP1A1 and CYP1A2) proteins and their respective activities was observed, with significant induction occurring in both the low and high dose CF 3 -PCB groups, compared to control. Additionally, CYP2B1 and CYP2B2 proteins and activities were induced following treatment with the high dose of 5,5′CF 3 -2,2′PCB. Since, 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) and related compounds selectively induce CYP1A1 and CYP1A2, the results suggest that 5,5′CF 3 -2,2′PCB has significant dioxin-like activity. Furthermore, 5,5′CF 3 -2,2′PCB appears to be acting as a mixed-type inducer since phenobarbitallike induction of CYP2B1 and 2B2 was also associated with exposure.

Background MCT-1 oncoprotein accelerates p53 protein degradation via a proteosome pathway. Synergistic promotion of the xenograft tumorigenicity has been demonstrated in circumstance of p53 loss alongside MCT-1 overexpression. However, the molecular regulation between MCT-1 and p53 in tumor development remains ambiguous. We speculate that MCT-1 may counteract p53 through the diverse mechanisms that determine the tumorigenic outcomes. Results MCT-1 has now identified as a novel target gene of p53 transcriptional regulation. MCT-1 promoter region contains the response elements reactive with wild-type p53 but not mutant p53. Functional p53 suppresses MCT-1 promoter activity and MCT-1 mRNA stability. In a negative feedback regulation, constitutively expressed MCT-1 decreases p53 promoter function and p53 mRNA stability. The apoptotic events are also significantly prevented by oncogenic MCT-1 in a p53-dependent or a p53-independent fashion, according to the genotoxic mechanism. Moreover, oncogenic MCT-1 promotes the tumorigenicity in mice xenografts of p53-null and p53-positive lung cancer cells. In support of the tumor growth are irrepressible by p53 reactivation in vivo, the inhibitors of p53 (MDM2, Pirh2, and Cop1) are constantly stimulated by MCT-1 oncoprotein. Conclusions The oppositions between MCT-1 and p53 are firstly confirmed at multistage processes that include transcription control, mRNA metabolism, and protein expression. MCT-1 oncogenicity can overcome p53 function that persistently advances the tumor development.

Tumor suppressor p53 protein mediates checkpoint controls and the apoptotic program that are critical for maintaining genomic integrity and preventing tumorigenesis. Forced-induction of MCT-1 decreased p53 expression before and after genomic insults. While inhibiting protein synthesis, the levels of ubiquinated-p53 and the phospho-MDMA2 were significantly increased in ectopic MCT-1 cells. Abrogation of the proteosome degradation process attenuated p53 destabilization and p21 down-regulation by MCT-1. Concomitantly, MCT-1 overexpression enhanced the phosphorylation status of MAPK (ERK1/ERK2). While MCT-1 gene knockdown or MEK/ERK pathway inhibition dramatically reduced MAPK phosphorylation, the genotoxin-induced p53 and p21 production were noticeably elevated. Upon Etoposide treatment, ectopic MCT-1 cells relaxed S-phase and G2/M checkpoints followed by G1 phase progressing. Moreover, cells inducing with MCT-1 abridged accumulations of G2/M populations in the response to gamma-irradiation. The polyploidy (DNA content>4N) populations were increased in association with p53 loss in MCT-1 oncogenic cells. Alkaline comet assay validated that ectopic MCT-1 cells were less susceptibility to the genotoxicity. Furthermore, the allocation of nuclear MCT-1 induced by the genotoxic stress was moderately coincided with gamma-H2AX appearances. Throughout damage-repairing process, ectopic MCT-1 cells displayed many larger chromosomes and multiple chromosomal fusions compared to the controls that showed increase in chromosomal breaks/gaps and minute chromosomal fragments. Spectral karyotyping analysis precisely identified the acquisition of a single extra copy of chromosome 14 together with a complex genome organizations in ectopic MCT-1 cells, including extra copies of chromosome segments that had been translocated to derivative chromosomes 6 [der(6)] and 9 [der(9)]. In conclusion, MCT-1 deregulates p53-p21 network and impairs the damage checkpoints those are robustly connected to oncogenic chromosomal abnormalities.

Contains fulltext : 57492.pdf (Publisher’s version ) (Open Access) Using the human bacterial artificial chromosome (BAC) fingerprint-based physical map, genome sequence assembly and BAC end sequences, we have generated a fingerprint-validated set of 32 855 BAC clones spanning the human genome. The clone set provides coverage for at least 98% of the human fingerprint map, 99% of the current assembled sequence and has an effective resolving power of 79 kb. We have made the clone set publicly available, anticipating that it will generally facilitate FISH or array-CGH-based identification and characterization of chromosomal alterations relevant to disease.

Item does not contain fulltext Microdeletions and microduplications, not visible by routine chromosome analysis, are a major cause of human malformation and mental retardation. Novel high-resolution, whole-genome technologies can improve the diagnostic detection rate of these small chromosomal abnormalities. Array-based comparative genomic hybridization allows such a high-resolution screening by hybridizing differentially labeled test and reference DNAs to arrays consisting of thousands of genomic clones. In this study, we tested the diagnostic capacity of this technology using approximately 3,500 flourescent in situ hybridization-verified clones selected to cover the genome with an average of 1 clone per megabase (Mb). The sensitivity and specificity of the technology were tested in normal-versus-normal control experiments and through the screening of patients with known microdeletion syndromes. Subsequently, a series of 20 cytogenetically normal patients with mental retardation and dysmorphisms suggestive of a chromosomal abnormality were analyzed. In this series, three microdeletions and two microduplications were identified and validated. Two of these genomic changes were identified also in one of the parents, indicating that these are large-scale genomic polymorphisms. Deletions and duplications as small as 1 Mb could be reliably detected by our approach. The percentage of false-positive results was reduced to a minimum by use of a dye-swap-replicate analysis, all but eliminating the need for laborious validation experiments and facilitating implementation in a routine diagnostic setting. This high-resolution assay will facilitate the identification of novel genes involved in human mental retardation and/or malformation syndromes and will provide insight into the flexibility and plasticity of the human genome.

Centrosome amplification and chromosome abnormalities are frequently detected in neoplasia and during tumorigenesis; however, the mechanism underlying these defects is still unclear. We here identify that the translational regulator, MCT-1, is a novel proto-oncoprotein located at the spindle-organizing apparatus. Decrease of cellular MCT-1 level results in intercellular bridging, chromosome mis-congregation, cytokinesis delay, and post-mitotic apoptosis. MCT-1 induction alongside p53 deficiency (MCT-1-p53) synergistically deregulates mitotic checkpoint kinases and induces Cyclin E protein degradation. These are implicated with increased frequency of cytokinesis failure, multi-nucleation, and centrosome amplification in the subsequent cell cycle. Consistent with the incidences of polyploidy and aneuploidy are progressively induced by the continued cell cultivation and further promoted by the disruption of microtubule structure, array CGH analysis confirms that the pronounced chromosome amplifications and deletions occur on MCT-1-p53 cellular background. This is the first demonstration that MCT-1 plays an important role in the regulation of centrosome integrity and mitotic progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A68.