Pancreatic cancer is characterized by its invasiveness, early metastasis, and the production of large amounts of extracellular matrix (ECM). We analyzed the influence of type I collagen and fibronectin on the regulation of cellular adhesion in pancreatic cancer cell lines to characterize the role of ECM proteins in the development of pancreatic cancer. We show that collagen type I is able to initiate a disruption of the E-cadherin adhesion complex in pancreatic carcinoma cells. This is due to the increased tyrosine phosphorylation of the complex protein B-catenin, which correlates with collagen type I-dependent activation of the focal adhesion kinase and its association with the E-cadherin complex. The activation and recruitment of focal adhesion kinase to the E-cadherin complex depends on the interaction of type I collagen with B1-containing integrins and an integrin-mediated activation of the cellular kinase Src. The disassembly of the E-cadherin adhesion complex correlates with the nuclear translocation of B-catenin, which leads to an increasing expression of the B-catenin-Lef/Tcf target genes, cyclin D1 and c-myc. In addition to that, cells grown on collagen type I show enhanced cell proliferation. We show that components of the ECM, produced by the tumor, contribute to invasiveness and metastasis by reducing E-cadherin-mediated cell-cell adhesion and enhance proliferation in pancreatic tumor cells.

The peptide hormone leptin plays a major role in the regulation of energy intake and expenditure and is predominantly expressed in mature adipocytes but not in preadipocytes. Using bisulfite genomic sequencing, we found that 32 CpGs, distributed within a 317-bp sequence of the proximal leptin promoter, were highly methylated in human preadipocytes (73.4% ؎ 9.0%). During maturation toward terminally differentiated adipocytes, this promoter region was extremely demethylated (9.4% ؎ 4.4%). CpG methylation-dependent transcriptional activity of the promoter fragment was determined in transfection experiments using a set of 5-truncated mock-, HhaI-, and SssI-methylated promoter-reporter constructs. Whereas the methylated CpG within the CCAAT/enhancer-binding protein ␣ recognition site down-regulated reporter expression, methylated CpGs proximal to the TATA motif and/or in a further upstream region abrogated promoter activity completely. These distinct promoter CpG sequences were found unmethylated in leptin-expressing mature adipocytes. As evidenced by electrophoretic mobility shift assays, nuclear protein complexes were specifically formed on methylated oligonucleotide probes corresponding to the dedicated promoter sequences, indicating that methyl-CpG binding proteins participate in transcriptional repression and regulation of the human leptin gene.

Primary mediastinal B-cell lymphoma (PMBL) is a well-defined subtype of diffuse large B-cell lymphoma. Molecular cytogenetics revealed frequent gains of 9p24. JAK2, mapping in this region, is presently regarded as a candidate oncogene because expression profiling showed high Janus kinase-2 (JAK2) transcript levels and JAK2 was found to be constitutively phosphorylated in mediastinal B-cell lymphomas. We confirm that in the MedB-1 mediastinal B-cell line, harboring a trisomy 9, JAK2 transcription is elevated and the product is highly

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During aging, telomeres are gradually shortened, eventually leading to cellular senescence. By T/C-FISH (telomere/centromere-FISH), we investigated human telomere length differences on single chromosome arms of 205 individuals in different age groups and sexes. For all chromosome arms, we found a linear correlation between telomere length and donor age. Generally, males had shorter telomeres and higher attrition rates. Every chromosome arm had its individual age-specific telomere length and erosion pattern, resulting in an unexpected heterogeneity in chromosome- specific regression lines. This differential erosion pattern, however, does not seem to be accidental, since we found a correlation between average telomere length of single chromosome arms in newborns and their annual attrition rate. Apart from the above-mentioned sex-specific discrepancies, chromosome arm-specific telomere lengths were strikingly similar in men and women. This implies a mechanism that arm specifically regulates the telomere length independent of gender, thus leading to interchromosomal telomere variations.

Evasion of apoptosis is a characteristic feature of pancreatic cancer, a prototypic cancer that is refractory to current treatment approaches. Hence, there is an urgent need to design rational strategies that counter apoptosis resistance. To explore X-linked inhibitor of apoptosis (XIAP) as a therapeutic target in pancreatic cancer, we analyzed the expression of XIAP in pancreatic tumor samples and evaluated the effect of small molecule XIAP inhibitors alone and in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) against pancreatic carcinoma in vitro and in vivo. Here, we report that XIAP is highly expressed in pancreatic adenocarcinoma samples compared with normal pancreatic ducts. Small molecule XIAP inhibitors synergize with TRAIL to induce apoptosis and to inhibit long-term clonogenic survival of pancreatic carcinoma cells. In contrast, they do not reverse the lack of toxicity of TRAIL on nonmalignant cells in vitro or normal tissues in vivo, pointing to a therapeutic index. Most importantly, XIAP inhibitors cooperate with TRAIL to trigger apoptosis and suppress pancreatic carcinoma growth in vivo in two preclinical models, i.e., the chorioallantoic membrane model and a mouse xenograft model. Parallel immunohistochemical analysis of tumor tissue under therapy reveals that the XIAP inhibitor acts in concert with TRAIL to cause caspase-3 activation and apoptosis. In conclusion, our findings provide, for the first time, evidence in vivo that XIAP inhibitors prime pancreatic carcinoma cells for TRAIL-induced apoptosis and potentiate the antitumor activity of TRAIL against established pancreatic carcinoma. These findings build the rationale for further (pre)clinical development of XIAP inhibitors and TRAIL against pancreatic cancer. [Cancer Res 2009;69(6):2425-34]

Background: Endobronchial forceps biopsies are often small and are associated with a relevant extent of artifacts. To overcome these limitations is an important task. Especially when considering predictive factors for pharmacological therapies of lung cancer (ERCC1, RRM1) a development of biopsy techniques seems to be essential. This is the first report on a new endobronchial biopsy technique called cryobiopsy. Objectives: In this study the feasibility and the potential advantages of applying cryoprobes for harvesting samples for histological examination in flexible bronchoscopies will be focused on. Methods: In 12 patients suffering from exophytic endobronchial malignancies, a modified flexible cryoprobe was used for immediate recanalization. The extracted tissue was examined histologically regarding sample quality and sample size. Results: Tissue samples obtained using the cryoprobe showed an extraordinary good quality in terms of size (median diameter of 6.7 mm, range 4.2–13 mm) and artifact-free sample area (75% of the samples showed an artifact-free sample area of more than 75%). Additionally molecular markers were shown to be well preserved. Conclusions: The new technique termed cryobiopsy might widen the chest physician’s range of tools for diagnostic bronchoscopies.

Telomere length analysis has aroused considerable interest in biology and oncology. However, most published data are pan-genomic Southern-blot-based estimates. We developed T/C-FISH (telomere/centromere-FISH), allowing precise measurement of individual telomeres at every single chromosome arm. Metaphase preparations are co-hybridized with peptide nucleic acid probes for telomeric sequences and the chromosome 2 centromere serving as internal reference. Metaphase images are captured and karyotyped using dedicated software. A software module determines the absolute integrated fluorescence intensities of the p- and q-telomeres of each chromosome and the reference signal. Normalized data are derived by calculating the ratio of absolute telomere and reference signal intensities, and descriptive statistics are calculated. T/C-FISH detects even small differences in telomere length. Using T/C-FISH we have discovered an epigenetic process occurring in the human male postzygote or early embryo: in umbilical cord blood lymphocytes, telomeres on male Xqs are around 1100 bp shorter than female Xqs.