Studies in rodents suggest the presence of a hepatopancreatic stem cell in adult pancreas that may give rise to liver cells in vivo. The aim of the present study was to determine the ability of human islet-derived cells to adopt a hepatic phenotype in vivo. Cultured human islet-derived progenitor cells that did not express albumin in vitro were stained with the red fluorescent dye PKH26 and injected into the liver of severe combined immunodeficiency mice. After 3 or 12 weeks, red fluorescent cells were detected in 11 of 15 livers and were mostly single cells that were well integrated into the liver tissue. Human albumin was found in 8 of 11 animals by immunohistochemistry, and human albumin mRNA was detected in 4 of 10 host livers. The mechanism underlying this phenomenon seems to be transdifferentiation, because human and mouse albumin were found to be expressed in distinct cells in the host liver

Beckwith–Wiedemann syndrome (BWS, OMIM 130650) is a congenital imprinting condition with a heterogenous clinical presentation of overgrowth and an increased childhood cancer risk (mainly nephroblastoma, hepatoblastoma or neuroblastoma). Due to the varying clinical presentation encompassing classical, clinical BWS without a molecular diagnosis and BWS-related phenotypes with an 11p15.5 molecular anomaly, the syndromic entity was extended to the Beckwith–Wiedemann spectrum (BWSp). The tumor risk of up to 30% depends on the molecular subtype of BWSp with causative genetic or epigenetic alterations in the chromosomal region 11p15.5. The molecular diagnosis of BWSp can be challenging for several reasons, including the range of causative molecular mechanisms which are frequently mosaic. The molecular basis of tumor formation appears to relate to stalled cellular differentiation in certain organs that predisposes persisting embryonic cells to accumulate additional molecular defects, which then results in a range of embryonal tumors. The molecular subtype of BWSp not only influences the overall risk of neoplasia, but also the likelihood of specific embryonal tumors.

Loss of PTEN is involved in tumor progression of several tumor entities including renal cell carcinoma (RCC). During the translation process PTEN generates a number of splice variants, including PTEN-Δ. We analyzed the impact of PTEN-Δ in RCC progression. In specimens of RCC patients the expression of PTEN-Δ and PTEN was quantified. The PTEN expressing RCC cell line A498 and the PTEN deficient 786-O cell line were stably transfected with the PTEN-Δ or PTEN transcript. In Caki-1 cells that highly express PTEN-Δ, this isoform was knocked down by siRNA. Cell migration, adhesion, apoptosis and signaling pathways activities were consequently analyzed in vitro. Patients with a higher PTEN-Δ expression had a longer lymph node metastasis free and overall survival. In RCC specimens, the PTEN-Δ expression correlated with the PTEN expression. PTEN-Δ as well as PTEN induced a reduced migration when using extracellular matrix (ECM) compounds as chemotaxins. This effect was confirmed by knockdown of PTEN-Δ, inducing an enhanced migration. Likewise a decreased adhesion on these ECM components could be shown in PTEN-Δ and PTEN transfected cells. The apoptosis rate was slightly increased by PTEN-Δ. In a phospho-kinase array and Western blot analyses a consequently reduced activity of AKT, p38 and JNK could be shown. We could show that the PTEN splice variant PTEN-Δ acts similar to PTEN in a tumor suppressive manner, suggesting synergistic effects of the two isoforms. The impact of PTEN-Δ in context of tumor progression should thus be taken into account when generating new therapeutic options targeting PTEN signaling in RCC.

Genomic imprinting evolved in a common ancestor to marsupials and eutherian mammals and ensured the transcription of developmentally important genes from defined parental alleles. The regulation of imprinted genes is often mediated by differentially methylated imprinting control regions (ICRs) that are bound by different proteins in an allele-specific manner, thus forming unique chromatin loops regulating enhancer-promoter interactions. Factors that maintain the allele-specific methylation therefore are essential for the proper transcriptional regulation of imprinted genes. Binding of CCCTC-binding factor (CTCF) to the IGF2/H19-ICR1 is thought to be the key regulator of maternal ICR1 function. Disturbances of the allele-specific CTCF binding are causative for imprinting disorders like the Silver-Russell syndrome (SRS) or the Beckwith-Wiedemann syndrome (BWS), the latter one being associated with a dramatically increased risk to develop nephroblastomas. Kaiso binding to the human ICR1 was detected and analyzed by chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assays (EMSA). The role of Kaiso-ICR1 binding on DNA methylation was tested by lentiviral Kaiso knockdown and CRISPR/Cas9 mediated editing of a Kaiso binding site. We find that another protein, Kaiso (ZBTB33), characterized as binding to methylated CpG repeats as well as to unmethylated consensus sequences, specifically binds to the human ICR1 and its unmethylated Kaiso binding site (KBS) within the ICR1. Depletion of Kaiso transcription as well as deletion of the ICR1-KBS by CRISPR/Cas9 genome editing results in reduced methylation of the paternal ICR1. Additionally, Kaiso affects transcription of the lncRNA H19 and specifies a role for ICR1 in the transcriptional regulation of this imprinted gene. Kaiso binding to unmethylated KBS in the human ICR1 is necessary for ICR1 methylation maintenance and affects transcription rates of the lncRNA H19.

Pain sensitivity of healthy subjects in the cold-pressor (CP) test was proposed to be dichotomously distributed and to represent a pain sensitivity trait. Still, it has not been systematically explored which factors influence this pain sensitivity readout. The aim of this study was to distinguish potential contributions of local tissue-related factors such as perfusion and thermoregulation or gain settings in nociceptive systems. Cold-pressor–sensitive and CP-insensitive students screened from a medical student laboratory course were recruited for a CP retest with additional cardiovascular and bilateral local vascular monitoring. In addition, comprehensive quantitative sensory testing according to Deutscher Forschungsverbund Neuropathischer Schmerz standards and a sustained pinch test were performed. Cold pressor was reproducible across sessions (Cohen kappa 0.61 ± 0.14, P < 0.005). At 30 seconds in ice water, CP-sensitive subjects exhibited not only more pain (78.6 ± 26.3 vs 29.5 ± 17.5, P < 0.0001) but also significantly stronger increases in mean arterial blood pressure (12.6 ± 9.3 vs 5.6 ± 8.1 mm Hg, P < 0.05) and heart rate (15.0 ± 8.2 vs 7.1 ± 6.2 bpm, P < 0.005), and lower baroreflex sensitivity, but not local or vasoconstrictor reflex–mediated microcirculatory responses. Cold-pressor–sensitive subjects exhibited significantly lower pain thresholds also for cold, heat, and blunt pressure, and enhanced pain summation, but no significant differences in Aδ-nociceptor–mediated punctate mechanical pain. In conclusion, differences in nociceptive signal processing drove systemic cardiovascular responses. Baroreceptor activation suppressed pain and cardiovascular responses more efficiently in CP-insensitive subjects. Cold-pressor sensitivity generalized to a pain trait of C-fiber–mediated nociceptive channels, which was independent of local thermal and vascular changes in the ice-water–exposed hand. Thus, the C-fiber pain trait reflects gain setting of the nociceptive system.