Dishevelled proteins and CYLD reciprocally regulate each other in CML cell lines.

Dishevelled (Dvl) proteins are activated by Wnt pathway stimulation and have crucial roles in the regulation of ß-catenin destruction complex. CYLD is a tumor suppressor and a deubiquitination enzyme. CYLD negatively regulates the Wnt/ß-catenin signaling pathway by deubiquitinating Dvl proteins. Loss of function and mutations of CYLD were linked to different types of solid tumors. Loss of function in CYLD is associated with Dvl hyper ubiquitination, resulting in the transmission of Wnt signaling to downstream effectors. ß-catenin upregulation is observed during disease progression in chronic myeloid leukemia (CML). Deregulated Dvl signaling may be a reason for ß-catenin activation in CML; and CYLD may contribute to Dvl deregulation. First, we evaluated mRNA expression in three CML cell lines and mRNA expression of the CYLD gene was found to be present in all (K562, MEG01, KU812). Unlike solid tumors sequencing revealed no mutations in the coding sequences of the CYLD gene. DVL genes were silenced by using a pool of siRNA oligonucleotides and gene expression differences in CYLD was determined by RT-PCR and western blot. CYLD protein expression decreased after Dvl silencing. An opposite approach of overexpressing Dvl proteins resulted in upregulated CYLD expression. While previous reports have described CYLD as a regulator of DVL proteins; our data suggests the presence of a more complicated reciprocal regulatory mechanism in CML cell lines.

Expression profiling of stem cell signaling alters with spheroid formation in CD133high/CD44high prostate cancer stem cells.

Cancer stem cells (CSC) isolated from multiple tumor types differentiate in vivo and in vitro when cultured in serum; however, the factors responsible for their differentiation have not yet been identified. The first aim of the present study was to identify CD133high/CD44high DU145 prostate CSCs and compare their profiles with non-CSCs as bulk counterparts of the population. Subsequently, the two populations continued to be three-dimensional multicellular spheroids. Differentiation was then investigated with stem cell-related genomic characteristics. Polymerase chain reaction array analyses of cell cycle regulation, embryonic and mesenchymal cell lineage-related markers, and telomerase reverse transcriptase (TERT) and Notch signaling were performed. Immunohistochemistry of CD117, Notch1, Jagged1, Delta1, Sox2, c-Myc, Oct4, KLF4, CD90 and SSEA1 were determined in CSC and non-CSC monolayer and spheroid subcultures. Significant gene alterations were observed in the CD133high/CD44high population when cultured as a monolayer and continued as spheroid. In this group, marked gene upregulation was determined in collagen type 9 α1, Islet1 and cyclin D2. Jagged1, Delta-like 3 and Notch1 were respectively upregulated genes in the Notch signaling pathway. According to immunoreactivity, the staining density of Jagged1, Sox2, Oct4 and Klf-4 increased significantly in CSC spheroids. Isolated CSCs alter their cellular characterization over the course of time and exhibit a differentiation profile while maintaining their former surface antigens at a level of transcription or translation. The current study suggested that this differentiation process may be a mechanism responsible for the malignant process and tumor growth.

Analysis of cytotoxic T lymphocyte antigen-4 (CTLA-4) exon 1 polymorphism in patients with type 1 diabetes mellitus in a Turkish population.

Recent studies have described linkage and association between cytotoxic T-lymphocyte antigen-4 (CTLA-4) gene polymorphism and type 1 diabetes mellitus (DM1) in some ethnic populations, but not others. This finding suggests that CTLA-4 gene association with DM1 may be influenced by the racial composition of the population. Thus, it is important to study the polymorphism of the CTLA-4 gene in different ethnic groups. In this case-control association study, the CTLA-4 gene exon 1 A/G polymorphism was analyzed in 48 children with DM1 and 80 healthy controls using polymerase chain reaction-restriction fragment length polymorphism analysis. The possible interaction of the CTLA-4 gene polymorphism with the presence of established genetic markers (HLA-DR genotyping) was also evaluated in 29 patients. The results of the present study do not suggest an association of the known polymorphism in exon 1 of the CTLA-4 gene with DM1 in this Turkish population, and G-allele containing CTLA-4 genotypes were not preferentially associated with age at clinical presentation or with presence of other genetic (HLA-DR3 or -DR4) markers of DM1.

MLL-AF4 gene rearrangement in a child with Epstein-Barr virus-related posttransplant B-cell lymphoma.

Recipients of solid organ allografts are known to be at increased risk of developing Epstein-Barr virus-related posttransplant lymphoproliferative diseases. A 28-month-old boy who had received a heterotopic liver transplant presented with lymphadenopathy in the abdomen, multiple nodules in the liver, and bilateral renal infiltration 19 months after transplantation. He was diagnosed with a Burkitt-like lymphoma based on bone marrow examination and the finding that the blastic cells in bone marrow were EBER-1 positive. Cytogenetic analysis of the bone marrow cells showed an MLL-AF4 rearrangement. He was treated with a combined chemotherapy regimen. He has been in continuous complete remission for 15 months now.

Microsatellite instability in early-onset breast cancer.

Breast cancer in a young person is considered a rare and very aggressive disease. The theories addressing the underlying genetic mechanisms of this disease are controversial. Therefore, additional genetic concepts playing a possible role in its pathogenesis and prognosis must be investigated. Microsatellite instability (MSI) characterized by a mutational process of insertions or deletions in microsatellite repeats might constitute a sensitive indicator for genomic instability in cancer. MSI has been described in a wide variety of tumors, particularly in hereditary non-polyposis colorectal cancer. The reports regarding its occurrence and prognostic significance in breast cancer are in conflict with each other. The purpose of this study was to investigate MSI in early-onset breast cancer and to correlate its occurrence with clinicopathological prognisticators. In this study, 16 female patients with primary breast cancer under 35 years of age (range 29-34) were investigated for the incidence of MSI in five microsatellite loci (D2S123, D3S1611, D17S807, D17S796 and Xq11-12) by comparing paired normal and tumor tissue DNA after PCR amplification from paraffin-embedded tissues. No instability was found in any of these five microsatellite loci. Although care must be taken not to overstate the importance of this result due to the inadequate number of microsatellite markers and DNA samples studied, this preliminary report indicates that MSI phenotype is uncommon in human early-onset breast cancer. Therefore, it does not appear to be related to the prognosis of disease.

Microsatellite instability is not a common feature in medullary breast cancer.

Microsatellite instability (MSI) is a form of genomic instability associated with defective DNA mismatch repair in tumors. MSI is found in 85-90% of hereditary nonpolyposis colorectal cancer cases; however, its occurrence in breast carcinogenesis still remains to be clarified. In addition, data are limited on the incidence of MSI in the medullary subtype. The purpose of this study was to investigate the occurrence of MSI in medullary breast cancer (MBC). The study included a total of 16 patients with MBC, nine with typical and seven with atypical histology. The incidence of MSI in five microsatellite loci (D2S123, D3S1611, D17S807, D17S796 and Xq11-12) was determined by comparing paired normal and tumor tissue DNA after PCR amplification from paraffin-embedded tissues. All 16 tumors showed stability at five loci. Although the number of microsatellite markers and DNA samples may limit the value of our results, we conclude that the MSI phenotype is uncommon in human MBC.