HER2 gene (ERBB2) amplification is a rare event in non-liver-fluke associated cholangiocarcinogenesis

Background

Cholangiocarcinoma is a rapidly fatal cancer entity with a median survival of less than one year. In contrast to many other malignancies, no substantial therapeutic breakthrough has been made in the past few decades, thereby limiting the treatment to cytotoxic chemotherapy with little beneficial effect for most patients. Targeted therapy tailored to the individual has shown substantial success in the recent past as a promising avenue for cancer therapy.

Methods

In this study, we determined the frequency of amplification of the HER2 gene in a comprehensive and well-characterized European cholangiocarcinoma cohort encompassing 436 patients including intrahepatic (n = 155), proximal (n = 155) and distal (n = 126) cholangiocarcinoma by strict application of a combined immunohistochemical and in situ hybridization algorithm following the current guidelines for HER2 assessment in gastric cancer.

Results

We identified a proportion of 1.4% (n = 6) patients that demonstrated HER2 gene amplification, with the highest rate among the distal cholangiocarcinoma patients (2.4%). None of the patients with equivocal (2+) immunohistochemical staining results exhibited gene amplification molecularly. In four of the five patients with HER2 positivity, gene amplification was already present in concomitantly tested high-grade biliary intraepithelial neoplasia (80%). HER2 gene amplification was not significantly associated with other clinical parameters, including survival.

Conclusions

This study identifies HER2 gene amplification as a rare event in cholangiocarcinoma of the Western population, occurring already in high-grade BilIN in a subset of patients. Furthermore, we provide a robust testing algorithm that may be used prior to therapy administration in future clinical trials evaluating the role of HER2 as a predictive marker in cholangiocarcinoma.

Induction of Chromosome Instability by Activation of Yes-Associated Protein and Forkhead Box M1 in Liver Cancer

BACKGROUND & AIMS

Many different types of cancer cells have chromosome instability. The hippo pathway leads to phosphorylation of the transcriptional activator yes-associated protein 1 (YAP1, YAP), which regulates proliferation and has been associated with the development of liver cancer. We investigated the effects of hippo signaling via YAP on chromosome stability and hepatocarcinogenesis in humans and mice.

METHODS

We analyzed transcriptome data from 242 patients with hepatocellular carcinoma (HCC) to search for gene signatures associated with chromosomal instability (CIN); we investigated associations with overall survival time and cancer recurrence using Kaplan-Meier curves. We analyzed changes in expression of these signature genes, at mRNA and protein levels, after small interfering RNA-mediated silencing of YAP in Sk-Hep1, SNU182, HepG2, or pancreatic cancer cells, as well as incubation with thiostrepton (an inhibitor of forkhead box M1 [FOXM1]) or verteporfin (inhibitor of the interaction between YAP and TEA domain transcription factor 4 [TEAD4]). We performed co-immunoprecipitation and chromatin immunoprecipitation experiments. We collected liver tissues from mice that express a constitutively active form of YAP (YAP^S127A) and analyzed gene expression signatures and histomorphologic parameters associated with chromosomal instability. Mice were given injections of thiostrepton and livers were collected and analyzed by immunoblotting, immunohistochemistry, histology, and real-time polymerase chain reaction. We performed immunohistochemical analyses on tissue microarrays of 105 HCCs and 7 nontumor liver tissues.

RESULTS

Gene expression patterns associated with chromosome instability, called CIN25 and CIN70, were detected in HCCs from patients with shorter survival time or early cancer recurrence. TEAD4 and YAP were required for CIN25 and CIN70 signature expression via induction and binding of FOXM1. Disrupting the interaction between YAP and TEAD4 with verteporfin, or inhibiting FOXM1 with thiostrepton, reduced the chromosome instability gene expression patterns. Hyperplastic livers and tumors from YAP^S127A mice had increased CIN25 and CIN70 gene expression patterns, aneuploidy, and defects in mitosis. Injection of YAP^S127A mice with thiostrepton reduced liver overgrowth and signs of chromosomal instability. In human HCC tissues, high levels of nuclear YAP correlated with increased chromosome instability gene expression patterns and aneuploidy.

CONCLUSIONS

By analyzing cell lines, genetically modified mice, and HCC tissues, we found that YAP cooperates with FOXM1 to contribute to chromosome instability. Agents that disrupt this pathway might be developed as treatments for liver cancer. Transcriptome data are available in the Gene Expression Omnibus public database (accession numbers: GSE32597 and GSE73396).

Abstract A46: Cellular apoptosis susceptibility (CAS) regulates integrin-beta1 and is required for tumor cell migration and invasion in hepatocellular carcinoma (HCC)

Nuclear transport is an essential, highly selective process in eukaryotic cells which guarantees the bidirectional communication between the nucleus and the cytoplasm. Emerging evidence suggests that aberrant expression of nuclear transport factors may contribute to cancer formation and progression. We could recently show that the nuclear exporter Cellular apoptosis susceptibility (CAS) is overexpressed in hepatocellular carcinoma (HCC), the functional implications of which remain, however, not completely understood. Here, we integrated proteomics, transcriptomics and functional assays with patient data to further characterize the role of CAS in HCC. We found that CAS depletion in HCC cells led to deregulation of integrins, particularly integrin-beta1, and resulted in reduced cell migration and invasion. Moreover, we determined that high expression levels of CAS in HCC cases were associated with macroangioinvasion and poorer patient outcome. Our data indicate that CAS is linked to integrin signaling and correlates with an aggressive HCC phenotype.

Citation Format: Juliane Winkler, Carsten Sticht, Amanda DiGuilio, Eva Maria Eiteneuer, Kerstin Holzer, Stephanie Rössler, Norbert Gretz, Kai Breuhahn, Peter Schirmacher, Alessandro Ori, Stephan Singer. Cellular apoptosis susceptibility (CAS) regulates integrin-beta1 and is required for tumor cell migration and invasion in hepatocellular carcinoma (HCC). [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr A46.

Solitonic Spin-Liquid State Due to the Violation of the Lifshitz Condition in Fe(1+y)Te

A combination of phenomenological analysis and Mössbauer spectroscopy experiments on the tetragonal Fe(1+y)Te system indicates that the magnetic ordering transition in compounds with higher Fe excess, y≥0.11, is unconventional. Experimentally, a liquidlike magnetic precursor with quasistatic spin order is found from significantly broadened Mössbauer spectra at temperatures above the antiferromagnetic transition. The incommensurate spin-density wave order in Fe(1+y)Te is described by a magnetic free energy that violates the weak Lifshitz condition in the Landau theory of second-order transitions. The presence of multiple Lifshitz invariants provides the mechanism to create multidimensional, twisted, and modulated solitonic phases.

The BH3-only protein BID impairs the p38-mediated stress response and promotes hepatocarcinogenesis during chronic liver injury in mice

Apoptosis is critical for maintaining tissue homeostasis, and apoptosis evasion is considered as a hallmark of cancer. However, increasing evidence also suggests that proapoptotic molecules can contribute to the development of cancer, including liver cancer. The aim of this study was to further clarify the role of the proapoptotic B-cell lymphoma 2 homology domain 3 (BH3)-only protein BH3 interacting-domain death agonist (BID) for chronic liver injury (CLI) and hepatocarcinogenesis (HCG). Loss of BID significantly delayed tumor development in two mouse models of Fah-mediated and HBsTg-driven HCG, suggesting a tumor-promoting effect of BID. Liver injury as well as basal and mitogen-stimulated hepatocyte proliferation were not modulated by BID. Moreover, there was no in vivo or in vitro evidence that BID was involved in DNA damage response in hepatocytes and hepatoma cells. Our data revealed that CLI was associated with strong activation of oxidative stress (OS) response and that BID impaired full activation of p38 after OS.

CONCLUSION

We provide evidence that the tumor-promoting function of BID in CLI is not related to enhanced proliferation or an impaired DNA damage response. In contrast, BID suppresses p38 activity and facilitates malignant transformation of hepatocytes.

Properties of injectable ready-to-use calcium phosphate cement based on water-immiscible liquid

Calcium phosphate cements (CPCs) are highly valuable materials for filling bone defects and bone augmentation by minimal invasive application via percutaneous injection. In the present study some key features were significantly improved by developing a novel injectable ready-to-use calcium phosphate cement based on water-immiscible carrier liquids. A combination of two surfactants was identified to facilitate the targeted discontinuous exchange of the liquid for water after contact with aqueous solutions, enabling the setting reaction to take place at distinct ratios of cement components to water. This prolonged the shelf life of the pre-mixed paste and enhanced reproducibility during application and setting reactions. The developed paste technology is applicable for different CPC formulations. Evaluations were performed for the formulation of an α-TCP-based CPC as a representative example for the preparation of injectable pastes with a powder-to-carrier liquid ratio of up to 85:15. We demonstrate that the resulting material retains the desirable properties of conventional CPC counterparts for fast setting, mechanical strength and biocompatibility, shows improved cohesion and will most probably show a similar degree of resorbability due to identical mineral structure of the set products.

Memory effect in Dy0.5Sr0.5MnO3 single crystals

We have performed a series of magnetic aging experiments on single crystals of Dy(0.5)Sr(0.5)MnO(3). The results demonstrate striking memory and chaos-like effects in this insulating half-doped perovskite manganite and suggest the existence of strong magnetic relaxation mechanisms of a clustered magnetic state. The spin-glass-like state established below a temperature T(sg)≈ 34 K originates from quenched disorder arising due to the ionic-radii mismatch at the rare earth site. However, deviations from the typical behavior seen in canonical spin glass materials are observed which indicate that the glassy magnetic properties are due to cooperative and frustrated dynamics in a heterogeneous or clustered magnetic state. In particular, the microscopic spin flip time obtained from dynamical scaling near the spin glass freezing temperature is four orders of magnitude larger than microscopic times found in atomic spin glasses. The magnetic viscosity deduced from the time dependence of the zero-field-cooled magnetization exhibits a peak at a temperature T < T(sg) and displays a marked dependence on waiting time in zero field.

[Videotape preparation of patients before hip replacement surgery improves mobility after three months]

Long-term follow-up investigations of the effect of psychological preparation on postoperative physical outcome measures have very rarely been done. In this study a three-month follow-up of a previous investigation of videotape preparation before hip replacement surgery is reported. 100 patients who previously participated in a randomized controlled study received physical examination and x-ray of the hip joint three months after the operation. The mobility of the replaced hip joint was recorded as well as ossifications of the joint. Prepared patients showed a significantly higher improvement of internal rotation, rotational range of motion, and abduction, compared to the controls. The effect sizes ranged between 21% and 32% and, thus, were of clinical relevance. Prepared patients showed less ossifications (15%) that controls (22%), this difference was not significant. For the first time it could be demonstrated that psychological preparation before surgery can not only improve short-term and psychosocial outcome parameters, but also long-term physical measures. The reason for this effect remains to be investigated.

Electrochemically assisted deposition of thin calcium phosphate coatings at near-physiological pH and temperature

An electrochemical method for the deposition of calcium phosphate phases on titanium surfaces using the galvanostatic mode is presented. Deposition was performed in a (Ca(2+) / H(x)PO(4) ((3-x)-))-containing electrolyte near physiological conditions with regard to pH (6.4) and temperature (36 degrees C). Cathodic alkalization leads first to the formation of a thin homogeneous layer that shows a nanoscale surface topography of alternating wall-like elevations and channels. It is thought that these channels in the calcium phosphate prelayer are formed as pathways for hydroxyl ions and hydrogen. Upon this layer, spheres of amorphous calcium phosphate (ACP) are formed as indicated by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy. According to transmission electron microscopy images, these spheres consist of small clusters of calcium phosphate (approximately 30 nm) and can grow up to 300 nm in diameter. Characteristic for this ACP is a high water content as seen by FTIR. As a function of current density, the ACP is then transformed into crystalline hydroxyapatite (HAP), which was identified using FTIR and X-ray diffraction. The morphology of the HAP crystals can be described as needles with dimensions of <500-nm length and <60-nm width. By choice of different electrochemical parameters, a homogeneous coating of either ACP, HAP, or the intermediate phase can be achieved, as shown in a kinetic phase diagram, thus allowing the formation of coatings with different properties in solubility and morphology.

Electrochemical behavior of titanium-based materials - are there relations to biocompatibility?

For biomedical applications the physico-chemical properties of oxide layers, always present in titanium-based materials, are of special interest because the biological system is in direct contact only with these oxides. Using electrochemical impedance spectroscopy and galvanostatic polarization it is shown that the different compositions of c.p.-titanium, Ti6Al4V, and Ti6Al7Nb result in different physico-chemical properties of air formed passive layers and anodic oxide layers. This may have a direct impact on the biocompatibility of these materials. Results of impedance spectroscopy distinctly differ in the flatband potentials as well as in the donor densities of air-formed passive layers with Ti6Al7Nb showing an approximately 50% smaller donor density than the other materials. Anodic galvanostatic polarization results in voltage-charge density curves with distinct differences in the Faraday efficiency epsilon of the oxide formation between Ti6Al7Nb and c.p.-titanium/Ti6Al4V, especially for low current densities. These effects correlate strongly with the donor densities in the air formed passive films of the examined materials. SEM-images of anodic oxide layers show a blister containing surface morphology of the outer part of the oxide layers for all materials. This morphology is probably caused by oxygen evolution, a process which relies on the transfer of electrons through the growing anodic oxide layers and strongly depends on the donor density in the air formed passive layers. Again, the much more pronounced morphology on c.p. titanium/Ti6Al4V agrees with the different donor densities in the air formed passive layers on the materials. These findings correlate with the good biocompatibility of Ti6Al7Nb and suggest that conduction mechanisms, in air formed passive layers and anodic oxide layers, contribute to processes that determine the biocompatibility of these materials.

Influence of sympathetic nervous system on dexamethasone-stimulated renal tubular transport of p-aminohippurate in young rats

After simultaneous administration of dexamethasone together with 6-hydroxydopamine or adrenergic neuronal blocking agents (alpha-methyldopa, reserpine, guanethidine) the dexamethasone-stimulated increase in renal excretion of p-aminohippurate (PAH) is distinctly diminished. The same is true for dopamine. This depressive effect could be proved by measurement of transport rates of PAH in renal cortical slices in vitro. The increase in kidney weight and in the protein content of kidney tissue in dexamethasone-treated rats is lower in rats simultaneously treated with adrenergic neuronal blocking agents of 6-hydroxydopamine. Adrenoceptor agonists and antagonists (pholedrine, orciprenaline, phentolamine, propranolol) are without influence on the dexamethasone-stimulated increase in PAH transport.