The Precise Breakpoint Mapping in Paracentric Inversion 10q22.2q23.3 by Comprehensive Cytogenomic Analysis, Multicolor Banding, and Single-Copy Chromosome Sequencing.

Detection and precise genomic mapping of balanced chromosomal abnormalities in patients with impaired fertility or a clinical phenotype represent a challenge for current cytogenomics owing to difficulties with precise breakpoint localization in the regions enriched for DNA repeats and high genomic variation in such regions. Here, we present a comprehensive cytogenomic approach to breakpoint mapping in a rare paracentric inversion on 10q (in a patient with oligoasthenoteratozoospermia and necrozoospermia) that does not affect other phenotype traits. Multicolor banding, chromosomal microarray analysis, chromosome microdissection with reverse painting, and single-copy sequencing of the rearranged chromosome were performed to determine the length and position of the inverted region as well as to rule out a genetic imbalance at the breakpoints. As a result, a paracentric 19.251 Mbp inversion at 10q22.2q23.3 was described. The most probable location of the breakpoints was predicted using the hg38 assembly. The problems of genetic counseling associated with enrichment for repeats and high DNA variability of usual breakpoint regions were discussed. Possible approaches for cytogenomic assessment of couples with balanced chromosome rearrangements and problems like reproductive failures were considered and suggested as useful part of effective genetic counseling.

Differential DNA Methylation of the IMMP2L Gene in Families with Maternally Inherited 7q31.1 Microdeletions is Associated with Intellectual Disability and Developmental Delay.

Most copy number variations (CNVs) in the human genome display incomplete penetrance with unknown underlying mechanisms. One such mechanism may be epigenetic modification, particularly DNA methylation. The IMMP2L gene is located in a critical region for autism susceptibility on chromosome 7q (AUTS1). The level of DNA methylation was assessed by bisulfite sequencing of 87 CpG sites in the IMMP2L gene in 3 families with maternally inherited 7q31.1 microdeletions affecting the IMMP2L gene alone. Bisulfite sequencing revealed comparable levels of DNA methylation in the probands, healthy siblings without microdeletions, and their fathers. In contrast, a reduced DNA methylation index and increased IMMP2L expression were observed in lymphocytes from the healthy mothers compared with the probands. A number of genes were upregulated in the healthy mothers compared to controls and downregulated in probands compared to mothers. These genes were enriched in components of the ribosome and electron transport chain, as well as oxidative phosphorylation and various degenerative conditions. Differential expression in probands and mothers with IMMP2L deletions relative to controls may be due to compensatory processes in healthy mothers with IMMP2L deletions and disturbances of these processes in probands with intellectual disability. The results suggest a possible partial compensation for IMMP2L gene haploinsufficiency in healthy mothers with the 7q31.1 microdeletion by reducing the DNA methylation level. Differential DNA methylation of intragenic CpG sites may affect the phenotypic manifestation of CNVs and explain the incomplete penetrance of chromosomal microdeletions.

Two Separate Cases: Complex Chromosomal Abnormality Involving Three Chromosomes and Small Supernumerary Marker Chromosome in Patients with Impaired Reproductive Function.

For medical genetic counseling, estimating the chance of a child being born with chromosome abnormality is crucially important. Cytogenetic diagnostics of parents with a balanced karyotype are a special case. Such chromosome rearrangements cannot be detected with comprehensive chromosome screening. In the current paper, we consider chromosome diagnostics in two cases of chromosome rearrangement in patients with balanced karyotype and provide the results of a detailed analysis of complex chromosomal rearrangement (CCR) involving three chromosomes and a small supernumerary marker chromosome (sSMC) in a patient with impaired reproductive function. The application of fluorescent in situ hybridization, microdissection, and multicolor banding allows for describing analyzed karyotypes in detail. In the case of a CCR, such as the one described here, the probability of gamete formation with a karyotype, showing a balance of chromosome regions, is extremely low. Recommendation for the family in genetic counseling should take into account the obtained result. In the case of an sSMC, it is critically important to identify the original chromosome from which the sSMC has been derived, even if the euchromatin material is absent. Finally, we present our view on the optimal strategy of identifying and describing sSMCs, namely the production of a microdissectional DNA probe from the sSMC combined with a consequent reverse painting.

Establishment of primary human breast cancer cell lines using "pulsed hypoxia" method and development of metastatic tumor model in immunodeficient mice.

BACKGROUND: Among breast cancer (BC) patients the outcomes of anticancer therapy vary dramatically due to the highly heterogeneous molecular characteristics of BC. Therefore, an extended panel of BC cell lines are required for in vitro and in vivo studies to find out new characteristic of carcinogenesis and metastasis. The purpose of this study was to develop patient-derived BC cell cultures and metastatic tumor models representing a tool for personal therapy and translational research. METHODS: Breast cancer cells were prepared by optimizing technique from tumor samples. We used real-time RT-PCR, flow cytometry, western blotting, cytotoxicity assay, karyotyping and fluorescent and electron microscopy analyses to characterize the established cell lines. BC xenografts in scid mice were used for in vivo tumorigenicity studies. RESULTS: The technique of preparing primary cells was optimized and this resulted in a high output of viable and active proliferated cells of nine patient-derived breast cancer cell lines and one breast non-malignant cell line. High E-cadherine and EpCAM expression correlated positively with epithelial phenotype while high expression of N-cadherine and Vimentin were shown in cells with mesenchymal phenotype. All mesenchymal-like cell lines were high HER3-positive-up to 90%. More interesting than that, is that two cell lines under specific culturing conditions (pulsed hypoxia and conditioned media) progressively transformed from mesenchymal to epithelial phenotypes displaying the expression of respective molecular markers proving that the mesenchymal-to-epithelial transition occurred. Becoming epithelial, these cells have lost HER3 and decreased HER2 membrane receptors. Three of the established epithelial cancer cell lines were tumorigenic in SCID mice and the generated tumors exhibited lobules-like structures. Ultrastructure analysis revealed low-differentiate phenotype of tumorigenic cell lines. These cells were in near-triploid range with multiple chromosome rearrangements. Tumorigenic BrCCh4e cells, originated from the patient of four-course chemotherapy, initiated metastasis when they were grafted subcutaneous with colonization of mediastinum lymph nodes. CONCLUSIONS: The developed BC cells metastasizing to mediastinum lymph nodes are a relevant model for downstream applications. Moreover, our findings demonstrate that pulsed hypoxia induces transformation of primary fibroblastoid breast cancer cells to epithelial-like cells and both of these cultures-induced and original-don't show tumor initiating capacity.