MicroRNAs of the chromosome 19 microRNA cluster (C19MC) are known to be abundantly expressed in the placenta. Their genes are located on the long arm of chromosome 19 and seem to be part of a large imprinted region. Although the data available so far suggest important functions in the placenta, no data are available on their general expression patterns in cultures of placenta-derived mesenchymal stromal cells (PDMSC). Surprisingly, qRT-PCR on tissue cultures from first-trimester and term placenta mesenchymal stromal cells showed an abundant expression of the cluster members miR-517a-3p, miR-519a-3p, and miR-520c-3p. Accordingly, analyses of methylation patterns suggested that these cells had escaped methylation and epigenetic silencing, respectively, of the paternal allele. This was confirmed by the results of treatment of chorionic villous stromal cells by the demethylating agent 5-Aza-2´deoxycytidine. Our results offer clear evidence that, in contrast to what is suggested in previous papers, members of C19MC are highly expressed in PDMSC indicating that their placenta-specific functions are not restricted to the trophoblast.

ABSTRACT: BACKGROUND: Structural rearrangements of chromosomal band 19q13 are a non-random cytogenetic abnormality in thyroid adenomas and adenomatous goiters and lead to an expression of miRNAs of the chromosome 19 microRNA cluster C19MC. Normally, expression of these miRNAs is silenced except for embryonic stem cells and the placenta where they represent the majority of miRNAs not only in the trophoblast but also in exosomes derived from it. PRESENTATION OF THE HYPOTHESIS: We have advanced the hypothesis that as part of the feto-maternal communication miRNAs of C19MC serve immunomodulatory functions in the placenta and confer a growth advantage to thyroid nodules by protecting them against autoimmune attacks. More precisely, the exosomes containing these miRNAs may specifically target immune cells in their local environment as well as systemically by transferring their cargo to recipient cells. Within these target cells the transferred miRNAs can interact with mRNAs of the recipient cells thereby suppressing their immune-specific functions. TESTING THE HYPOTHESIS: Experiments used to demonstrate the immunomodulatory capacity of placenta-derived exosomes can be modified by transfecting the target cells with those miRNAs of C19MC represented in placental exosomes. IMPLICATIONS OF THE HYPOTHESIS: Mimics of C19MC-derived miRNAs might develop to useful drug candidates for the treatment of autoimmune disease as e.g. rheumatoid arthritis and Sjogren's syndrome and for the prevention of transplant rejection. In case of tumor entities with elevated expression of C19MC miRNAs these miRNAs may be interesting targets for treatment with appropriate antagonists.

Cancer is a disease of uncontrolled cell proliferation causing approximately 13% of deaths worldwide. Cancer cell mechanics is currently an important topic of investigation in cancer diagnostics as a possible tool to distinguish malignant cells from normal cells in addition to increasing our understanding of pathophysiology of the disease. Our study, based on Atomic Force Microscopy (AFM) measurements on cells, shows that malignant thyroid cells are 3- to 5-fold softer in comparison to primary normal thyroid cells depending on duration between cell seeding and AFM experiments. These results reveal cultivation period as an important factor that influences cell mechanics and which must be considered when comparing cells. Investigation of actin cytoskeleton by fluorescent labelling revealed differences in organization of actin between malignant and normal thyroid cells, which may be directly contributing to alteration of cell mechanics in cancer cells.

Classical cytogenetic examination of a thyroid nodular goiter revealed the existence of two different cytogenetically aberrant cell clones. They were characterized by monosomy 13 as the sole abnormality in one clone, and loss of one chromosome 13 and a ring chromosome that was found to consist of chromosome 13 material by fluorescence in situ hybridization in the other clone. We have concluded that during the course of karyotypic evolution, the instability of the ring chromosome has led to its loss and subsequent monosomy 13. In the literature, two cases of partial monosomy 13 have been reported in adenomatous goiters, suggesting that this abnormality characterizes a rare but distinct subgroup of benign thyroid lesions histologically presenting as adenomatous goiters. Possible target genes of these deletions are the retinoblastoma (RB1) gene locus and the MIR16-1/15A cluster. Based on similar changes in other tumors, it seems reasonable to also analyze a large number of adenomatous goiters for submicroscopic deletions of the long arm of chromosome 13.

MicroRNAs are a class of macromolecules of rapidly emerging significance for the pathogenesis of numerous human diseases including cancer. Moreover, many of them hold great promise as valid biomarkers because of their high extracellular stability. Chromosome 19 harbours the largest cluster of microRNA genes known so far which has developed in a very short time during mammalian evolution. Thus, in terms of evolution, gain of this cluster is an apparent success story. Nevertheless, we know very little about how functions of its microRNAs have contributed to this success and apparently, at least some of them can turn from Jekyll into Hyde and contribute to tumorigenesis. Recent work published in The Journal of Pathology by Fornari and colleagues, addressed here, reveals how members of that cluster are involved in the molecular pathogenesis of hepatocellular carcinomas. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The results of cytogenetic and molecular cytogenetic investigations revealed similarities in genetic background and biological behaviour between tumours and genetic diseases of humans and dogs. These findings classify the dog a good and accepted model for human cancers such as osteosarcomas, mammary carcinomas, oral melanomas and others. With the appearance of new studies and advances in canine genome sequencing, the number of known homologies in diseases between these species raised and still is expected to increase. In this context, array-based comparative genomic hybridization (aCGH) provides a novel tool to rapidly characterize numerical aberrations in canine tumours or to detect copy number aberrations between different breeds. As it is possible to spot probes covering the whole genome on each chip to discover copy number aberrations of all chromosomes simultaneously, this method is time-saving and cost-effective - considering the relation of costs and the amount of data obtained. Complemented with traditional methods like karyotyping and fluorescence in situ hybridization (FISH) analyses, the aCGH is able to provide new insights into the underlying causes of canine carcinogenesis.

ABSTRACT: BACKGROUND: Spontaneous cessation of growth is a frequent finding in uterine fibroids. Increasing evidence suggests an important role of cellular senescence in this growth control. Deciphering the underlying mechanisms of growth control that can be expected not only to shed light on the biology of the tumors but also to identify novel therapeutic targets. Methods: We have analyzed uterine leiomyomas and matching normal tissue for the expression of p14Arf and used explants to see if reducing the MDM2 activity using the small-molecule inhibitor nutlin-3 can induce p53 and activate genes involved in senescence and/or apoptosis. For these studies quantitative real-time RT-PCR, Western blots, and immunohistochemistry were used. Statistical analyses were performed using the student's t test. Results: An in depth analysis of 52 fibroids along with matching myometrium from 31 patients revealed in almost all cases a higher expression of p14Arf in the tumors than in the matching normal tissue. In tissue explants, treatment with the MDM2 inhibitor nutlin-3 induced apoptosis as well as senescence as revealed by a dose-dependent increase of the expression of BAX as well as of p21, respectively. Simultaneously, the expression of the proliferation marker Ki-67 drastically decreased. Western-blot analysis identified an increase of the p53 level as the most likely reason for the increased activity of its downstream markers BAX and p21. Because as a rule fibroids express much higher levels of p14Arf, a major negative regulator of MDM2, than matching myometrium it was then analyzed if fibroids are more sensitive against nutlin-3 treatment than matching myometrium. We were able to show that in most fibroids analyzed a higher sensibility than that of matching myometrium was noted with a corresponding increase of the p53 immunopositivity of the fibroid samples compared to those from myometrium. Conclusions: The results show that uterine fibroids represent a cell population of advanced cellular age compared to matching myometrium. Moreover, the data point to members of the p53-network as to potential novel therapeutic targets for the treatment of uterine fibroids.

Recurrent chromosomal alterations are found in roughly 20% of all uterine fibroids but in the majority cytogenetic changes are lacking. Recently, mutations of the gene mediator subcomplex 12 (MED12) have been detected in a majority of fibroids but no information is available whether or not they co-occur with cytogenetic subtypes as e.g. rearrangements of the genes encoding high mobility group AT-hook (HMGA) proteins. In a total of 80 cytogenetically characterized fibroids from 50 patients we were not only able to confirm the frequent occurrence of MED12 mutations but also to stratify two mutually exclusive pathways of leiomyomagenesis with either rearrangements of MED12 reflected by clonal chromosome abnormalities affecting 12q14∼15 or by mutations affecting exon 2 of MED12. On average the latter mutations were associated with a significantly smaller tumor size. However, G>A transitions of nucleotides c.130 or c.131 correlate with a significantly larger size of the fibroids compared to other MED12 mutations thus explaining the high prevalence of the former mutations among clinically detectable fibroids. Interestingly, fibroids with MED12 mutations expressed significantly higher levels of the gene encoding wingless-type MMTV integration site family, member 4 (WNT4). Based on these findings and data from the literature we hypothesize that estrogen and the mutated MED12 cooperate in activating the Wnt pathway which in turn activates β-catenin known to cause leiomyoma-like lesions in a mouse model. The occurrence of a "fibroid-type mutation" in a rare histologic subtype of endometrial polyps suggests that this mechanism is not confined to uterine leiomyomas.

The t(2;3)(q13;p25) occurs in a subgroup of follicular-patterned thyroid tumors and leads to a fusion of the genes encoding for the thyroid-specific transcription factor paired box 8 (PAX8) and the peroxisome proliferator-activated receptor gamma (PPARγ). Although initially discovered in follicular carcinomas (FTC), the fusion transcripts were also detected in a small fraction of follicular adenomas and rarely in follicular variants of papillary carcinomas (FV-PTC). In most RT-PCR based studies, fresh or snap-frozen tissue samples were used. The aim of the present study was to develop a method for the detection of chimeric PAX8-PPARG transcripts in formalin-fixed paraffin-embedded (FFPE) thyroid tumor samples by conventional RT-PCR. For this purpose, RNA from FFPE samples of 21 FTC, seven FV-PTC, and one bone metastasis derived from an FTC was subjected to RT-PCR with subsequent gel electrophoretic separation of the products. Fusion transcripts were detected in 2/21 primary FTC (9.5%) and in the bone metastasis, but they were undetectable in all seven FV-PTC under investigation. The RT-PCR approach described herein allows to detect all known variants of PAX8-PPARG fusion transcripts and is applicable to FFPE tissues. Thus, it can be used to screen archival thyroid tumor samples for the gene fusion. © 2011 Wiley Periodicals, Inc.