Generation of three CRISPR/Cas9 edited human induced pluripotent stem cell lines (DHMi005-A-5, DHMi005-A-6 and DHMi005-A-7) carrying a Holt-Oram Syndrome patient-specific TBX5 mutation with known cardiac phenotype and a FLAG-tag after exon 9 of the TBX5 gene

TBX5 is a transcription factor (TF) playing essential role during cardiogenesis. It is well known that TF mutations possibly result in non- or additional binding of the DNA due to conformational changes of the protein. We introduced a Holt-Oram Syndrome (HOS) patient-specific TBX5 mutation c.920_C > A heterozygously in a healthy induced pluripotent stell cell (iPSC) line. This TBX5 mutation results in conformational changes of the protein and displayed ventricular septal defects in the patient itself. Additionally we introduced a FLAG-tag on the TBX5 mutation-carrying allele. The resulting heterozygous TBX5-FLAG iPSC lines are a powerful tool to investigate altered TF activity bonding.

Generation of two CRISPR/Cas edited human induced pluripotent stem cell lines (DHMi005-A-3 and DHMi005-A-4) carrying a FLAG-tag after exon 9 of the TBX5 gene

Although TBX5 plays a major role during human cardiogenesis and initiates and controls limb development, many of its interactions with genomic DNA and the resulting biological consequences are not well known. Existing anti-TBX5-antibodies work very inefficiently in certain applications such as ChIP-Seq analysis. To circumvent this drawback, we introduced a FLAG-tag sequence into the TBX5 locus at the end of exon 9 prior to the stop codon by CRISPR/Cas9. The expressed TBX5-FLAG fusion protein can effectively be precipitated by anti-FLAG antibodies. Therefore, these gene-edited iPSC lines represent powerful cellular in vitro tools to unravel TBX5:DNA interactions in detail.

A miRNA derived from the 17/92 cluster is a novel player in programming pulmonary hypertension in response to gestational hypoxia via NADPH oxidases and the mTOR pathway

Background

Gestational hypoxia can lead to intrauterine growth restriction (IUGR) and programming of cardiovascular diseases in adulthood via different, although not completely understood, epigenetic mechanisms. We have previously shown that reactive oxygen species (ROS) derived from NADPH oxidases contribute to hypoxia induced pulmonary hypertension (PH). However, their role in disease programming by gestational hypoxia is not resolved.

Purpose

We aimed to elucidate the role of NADPH oxidases and redox sensitive miRNAs in the cardiovascular response of adult offspring to transient gestational hypoxia.

Methods

Wildtype (WT) and nmf333 mice, lacking a functional p22phox dependent NADPH oxidase, were exposed to gestational hypoxia from E10.5 to E11.5. Embryos and adult offspring were analyzed by functional, immunohistochemical and molecular methods including mRNA and miRNA profiling. miRNA mimics or inhibitors were applied in vivo and in vitro using embryoid bodies (EBs). Heart samples from patients with right heart disease associated with congenital heart disease (CHD) were used to validate target miRNA expression.

Results

Transient gestational hypoxia was sufficient to induce IUGR in embryos and pulmonary hypertension (PH) characterized by right ventricular hypertrophy, increased right ventricular pressure and pulmonary vascular remodeling in adult offspring from WT mice while p22phox-deficient nmf333 mice were protected. Cardiac mRNA and miRNA profiling followed by qPCR validation identified several single miRNAs derived from the 17/92 miRNA cluster as downregulated by gestational hypoxia and NADPH oxidases in embryos and adult offspring hearts. In vitro analyses using EBs validated a single miRNA from this cluster to be sufficient to induce cardiac differentiation in response to hypoxia and p22phox, and target analyses identified the mTOR pathway as dysregulated. Treatment with an inhibitor targeting this miRNA was sufficient to induce PH in adult mice, while treating offspring derived from gestational hypoxia pregnancies with an miRNA mimic prevented the development of PH in the adult and dysregulation of the mTOR pathway. Importantly, expression of this single miRNA from the miRNA 17/92 cluster was negatively correlated to right ventricular pressure in CHD patients.

Conclusions

In this study, we demonstrate that gestational hypoxia programs PH in adulthood by upregulating NADPH oxidases and downregulating miRNAs derived from the 17/92 cluster subsequently affecting the mTOR pathway. Since dysregulation of a single miRNA from this cluster induced not only PH but was also associated with right ventricular pressure in CHD patients, these findings might open novel options for diagnosis, prevention and treatment of right heart disease.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): DZHK (German Centre for Cardiovascular Research)

Establishment of an induced pluripotent stem cell line DHMi005-A from a healthy male proband

We generated an induced pluripotent stem cell (iPSC) line from a healthy male 29-year-old proband. Adipose fibroblasts (AFs) were reprogrammed using Sendai virus. Generated iPSCs showed typical stem cell morphology. From passage 9 on, iPSCs were free of virus. Pluripotency in the iPSCs was verified and spontaneous differentiation showed expression of all three germ layers. Karyotyping indicated no anomalies for the generated iPSCs. Many patient-specific iPSCs are generated from subcutaneous fat fibroblasts obtained during surgical procedure. The described control iPSC line was generated equally and therefore serves as an ideal control for adipose-fibroblast-based patient-specific iPSC lines in disease modeling.

Establishment of a patient-specific induced pluripotent stem cell line DHMi004-A from a male Holt-Oram syndrome patient with verified TBX5 mutation

The Holt-Oram syndrome (HOS) is a rare autosomal dominant disorder, mostly based on mutations in the TBX5 gene. Patients show malformation of at least one upper limb along with congenital heart defects. The established induced pluripotent stem cell (iPSC) line was generated from a patient displaying pronounced and typical features of HOS and carrying a single-nucleotide change c.920_C>A leading to an amino acid change from proline to threonine at amino acid position 85, which appeared de novo. Adipose fibroblasts from the patient were reprogrammed using Sendai virus. Pluripotency of the iPSCs was fully demonstrated.

[Successful individualized and targeted therapy of an NSCLC patient with Gefitinib based on a predictive assessment of the EGF-receptor mutation status]

BACKGROUND

Molecular alterations in the tyrosine kinase (TK) domain of the human epidermal growth factor receptor (EGFR) have been correlated with tumour remission upon treatment with the TK inhibitor Gefitinib in non-small cell lung cancer (NSCLC). We have retrospectively investigated the correlation of point mutations with clinical response and, based on our retrospective results, used predictive molecular assessment as the basis for treatment in one patient.

METHODS

Mutational analysis was performed in 11 NSCLC-patients (10 responders, 1 non-responder) among 62 patients treated with Gefitinib within an expanded access program.

RESULTS

Activating molecular alterations were found in 8/11 investigated samples (point mutations in exons 18 and 21, deletions in exon 19). All molecular changes were found in adenocarcinoma or bronchioloalveolar carcinoma. The tumours of two male responders with squamous cell carcinoma showed either a wild-type sequence or carried a nonsense mutation. In one patient treatment with Gefitinib after prospective assessment of mutations resulted in tumour remission and thus proved to be predictive.

CONCLUSIONS

Mutations in the EGFR TK domain correlate with the clinical response to Gefitinib. The predictive assessment of molecular alterations may thus be helpful for treatment decisions in selected cases. A clinical response to Gefitinib is nevertheless also found in patients with wild-type EGFR.

Impact of RASSF1A methylation on survival of stage IIIb and IV NSCLC patients treated with gemcitabine

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Background: The epigenetic inactivation of genes plays an important role in lung cancer carcinogenesis. We have investigated the methylation status of seven genes (APC1A, DAPK, FHIT, p14ARF, p16INK4a, RARβ, RASSF1A) in serum DNA of NSCLC patients and analyzed their potential prognostic value. Methods: Blood samples were drawn pretherapeutically. Genomic DNA was purified from serum and subjected to sodium bisulfite treatment to convert unmethylated cytosine bases. Epigenetic alteration was detected by a nested methylation-specific PCR. Results: We have investigated a group of 92 patients with histologically confirmed NSCLC (60 males, 32 females; 21 stage IIIb, 71 stage IV; median age 60.9 years, range 34–78). All patients received gemcitabine first-line alone or in combination with other drugs. The vast majority of samples (n = 87) showed at least one methylated gene. More than half of the tested genes were hypermethylated in 20 samples (21.7%). The methylation frequencies of individual genes were 30.8% (APC1A), 26.1% (DAPK), 47.3% (FHIT), 30.4% (p14ARF), 25.9% (p16INK4a), 44.6% (RARβ) and 33.3% (RASSF1A). The hypermethylation status of none of the genes altered median overall survival (11.0 ± 1.4 mo) of the total population significantly. However, patients with a methylated RASSF1A gene who showed a partial response (n = 27) survived significantly longer (33.6 ± 10.4 mo) compared to those with a wild-type allele (16.1 ± 4.7 mo, P = 0.0045). This difference was not seen in patients with stable (n = 40) or progressive (n = 20) disease. Conclusions: Our results show that the hypermethylation frequency of single genes and the accumulation of epigenetic alterations in individual samples of NSCLC patients may vary considerably. Molecular parameters such as RASSF1A hypermethylation may be useful prognostic markers in subpopulations.

[Table: see text]

[Non-small-cell lung cancer third-line therapy with gefitinib]

The EGFR-inhibition via tyrosine-kinase-inhibitor gefitinib (Iressa) constitutes a new way to treat non-small-cell lung cancer. Recent research results enable us to better understand the basics of molecular targeted therapy (MTT). These results are helpful to re-interpret the clinical results obtained so far for gefitinib and to consider for the first time in a predictive manner factors for the selection of patients suitable for therapy. Three case reports are presented in this paper which illustrate that -- with view to the results from translational research -- the use of gefitinib offers an efficient new therapeutic modality for the treatment of chemotherapy-resistant non-small-cell lung cancer.

Peri/nuclear localization of intact insulin-like growth factor binding protein-2 and a distinct carboxyl-terminal IGFBP-2 fragment in vivo

Insulin-like growth factor binding protein-2 (IGFBP-2) as one of the most important IGFBPs has never been assessed in the intracellular compartment in vivo. Since there is evidence for novel intracellular functions of distinct IGFBPs, we investigated the presence of IGFBP-2 inside the cell. In peri/nuclear fractions of various tissues isolated from IGFBP-2 transgenic and non-transgenic mice we were able to show the presence of intact IGFBP-2. In addition, we demonstrate the presence of a highly conserved carboxyl-terminal IGFBP-2 fragment in the peri/nuclear fraction by using different peptide-induced antibodies. In pancreatic sections, confocal microscopy revealed the presence of IGFBP-2 on the nuclear surface but not within the nucleus. Our findings suggest novel functions of intact IGFBP-2 and IGFBP-2 fragments within the cell.

Insulin-like growth factor-binding protein-4 inhibits growth of the thymus in transgenic mice

Numerous in vitro studies have demonstrated that IGF-binding protein (IGFBP)-4 is a consistent inhibitor of IGF actions. In order to investigate the functions of IGFBP-4 in vivo, transgenic mice were generated by microinjection of a transgene, in which the murine Igfbp4 cDNA is driven by the H-2K(b) promoter, and followed by a splicing cassette and polyadenylation signal of the human beta-globin gene. Transgene mRNA was expressed ubiquitously, and elevated IGFBP-4 protein was detected in the spleen, thymus, kidney and lung of transgenic mice. The activities of serum IGFBPs were not changed in transgenic mice. Immunohistochemical studies revealed transgene expression predominantly in the thymic medulla and red pulp of the spleen. Body weight and the weights of the spleen, kidney and lung of transgenic mice were not different from controls. In contrast, the thymus of transgenic mice showed a significantly reduced weight and cortex volume. In transgenic thymus and spleen, cell proliferation was inhibited and apoptosis was stimulated. Transgenic mice showed normal T- and B-cell development and normal basal plasma immunoglobulin levels. In conclusion, overexpression of IGFBP-4 inhibits growth of the thymus. IGFBP-4 excess inhibits cell proliferation and stimulates apoptosis in lymphoid tissues, but does not affect lymphocyte development. These findings suggest that IGFBP-4 is a potential growth inhibitor of lymphoid tissues.

Increased activity of catalase in tumor cells overexpressing IGFBP-2

Elevated levels of IGFBP-2 are found in serum and tissues under various stressful conditions and in many malignancies. In previous studies, we have shown that overexpression of IGFBP-2 results in increased tumorigenic potential in Y-1 mouse adrenocortical tumor cells, and that these effects are presumably mediated through IGF-independent mechanisms. Here, we show that highly proliferative IGFBP-2-overexpressing Y-1 cells, but not control Y-1 cells, grow to very high cell densities. In order to evaluate whether the increased cell densities in IGFBP-2-transfected Y-1 cells were accompanied by alterations in the oxidative stress system, we analyzed the effect of IGFBP-2 overexpression on the activity of various antioxidative enzymes in two malignant cell lines. Among the tested antioxidative enzymes (catalase, superoxide-dismutase, glutathione peroxidase, glutathione S-transferase), only catalase enzyme activity was significantly higher in IGFBP-2-transfected Y-1 mouse adrenocortical tumor cells and in IGFBP-2-transfected human colon tumor cells (Caco-2) compared to control-transfected Y-1 and Caco-2 cells and non-tumor 293 human epithelial cells. However, overexpression of catalase in malignant cells did not result in increased resistance to oxidative stress as measured by cell viability and protein oxidation after treatment of the cells with hydrogen peroxide. This might be due to an upregulation of the GST enzyme activity after treatment with H (2)O (2) that we observed selectively in the control-transfected Y-1 cells and which might compensate for the higher catalase activity in the IGFBP-2 overexpressing cells. In summary, we found a strong and selective upregulation of the catalase activity in IGFBP-2 overexpressing malignant Y-1 and Caco-2 cell lines that might contribute to the highly malignant phenotype of IGFBP-2 overexpressing tumors through as yet unknown mechanisms.

IGF-binding protein-4: biochemical characteristics and functional consequences

IGFs have multiple functions regarding cellular growth, survival and differentiation under different physiological and pathological conditions. IGF effects are modulated systemically and locally by six high-affinity IGF-binding proteins (IGFBP-1 to -6). Despite their structural similarity, each IGFBP has unique properties and exhibits specific functions. IGFBP-4, the smallest IGFBP, exists in both non-glycosylated and N-glycosylated forms in all biological fluids. It is expressed by a wide range of cell types and tIssues, and its expression is regulated by different mechanisms in a cell type-specific manner. IGFBP-4 binds IGF-I and IGF-II with similar affinities and inhibits their actions under almost all in vitro and in vivo conditions. In this review, we summarize the available data regarding the following aspects of IGFBP-4: genomic organization, protein structure-function relationship, expression and its regulation, as well as IGF-dependent and -independent actions. The biological significance of IGFBP-4 for reproductive physiology, bone formation, renal pathophysiology and cancer is discussed.

Prognostic significance of cytokine modulation in non-small cell lung cancer

Increased production of immunosuppressive interleukin-10 (IL-10) by non-small cell lung cancer (NSCLC) and increased serum IL-10 concentrations in NSCLC-patients have recently been correlated to reduced survival. We earlier demonstrated suppression of IL-2 secretion in whole blood cell cultures of NSCLC-patients. We now analyzed the influence of IL-2 secretion on survival in NSCLC-patients and the influence of IL-10 on IL-2 secretion. The correlation of the IL-2 producing ability of whole blood cells in response to PHA in 90 NSCLC-patients at the time of diagnosis to survival was calculated by Crit-level, the Kaplan-Meier method and the log-rank test. With a cut-off value of IL-2 production of 1,100 pg/ml by whole blood cells the difference in survival was significant with a p-value of 0.014. In the group with high and low IL-2, median survival was 14.1 and 9.7 months, respectively. In the subgroup of 33 surgically-treated patients the difference in survival was significant with a p-value of 0.011. In 14 patients with surgical resection of the tumor and high IL-2 at diagnosis and 19 patients with surgical resection, but low IL-2 at diagnosis, median survival was 86.2 and 11.3 months, respectively. Secretion of IL-2 in whole blood cell cultures from healthy individuals was inhibited in a dose-dependent manner upon addition of IL-10. Taken together, suppression of IL-2 secretion has prognostic significance for survival of NSCLC-patients and may be mediated by tumor-derived IL-10.

Mutation of the RGD sequence does not affect plasma membrane association and growth inhibitory effects of elevated IGFBP-2 in vivo

Using insulin-like growth factor-binding protein-2 (IGFBP-2) transgenic mice (D mice) as a model of elevated IGFBP-2 expression, which is often found in unphysiological conditions, we found association of IGFBP-2 to purified plasma membranes of many organs. To determine whether the RGD (Arg-Gly-Asp) motif of IGFBP-2 mediates cell surface binding in vivo, we mutated the RGD motif of IGFBP-2 into an RGE (Arg-Gly-Glu) sequence and produced transgenic mice (E mice) which express elevated amounts of mutated IGFBP-2. Our data demonstrate that in vivo IGFBP-2 cell surface association is not dependent on the RGD motif and that mutation of this sequence does not alter growth inhibitory effects of IGFBP-2.