Identification and validation of fusidic acid and flufenamic acid as inhibitors of SARS-CoV-2 replication using DrugSolver CavitomiX

In this work, we present DrugSolver CavitomiX, a novel computational pipeline for drug repurposing and identifying ligands and inhibitors of target enzymes. The pipeline is based on cavity point clouds representing physico-chemical properties of the cavity induced solely by the protein. To test the pipeline's ability to identify inhibitors, we chose enzymes essential for SARS-CoV-2 replication as a test system. The active-site cavities of the viral enzymes main protease (M^pro) and papain-like protease (Pl^pro), as well as of the human transmembrane serine protease 2 (TMPRSS2), were selected as target cavities. Using active-site point-cloud comparisons, it was possible to identify two compounds-flufenamic acid and fusidic acid-which show strong inhibition of viral replication. The complexes from which fusidic acid and flufenamic acid were derived would not have been identified using classical sequence- and structure-based methods as they show very little structural (TM-score: 0.1 and 0.09, respectively) and very low sequence (~ 5%) identity to M^pro and TMPRSS2, respectively. Furthermore, a cavity-based off-target screening was performed using acetylcholinesterase (AChE) as an example. Using cavity comparisons, the human carboxylesterase was successfully identified, which is a described off-target for AChE inhibitors.

Binding and inactivation of human coronaviruses, including SARS-CoV-2, onto purified clinoptilolite-tuff

The current COVID19 pandemic is caused by a positive-sense single-stranded RNA virus, which presents high mutational rates. The development of effective therapeutics and mitigation strategies using vaccination or therapeutic antibodies faces serious challenges because of the regular emergence of immune escape variants of the virus. An efficient approach would involve the use of an agent to non-specifically limit or block viruses contacting the mucosae and therefore entering the body. Here, we investigated the ability of a micronized purified clinoptilolite-tuff to bind and neutralize different viruses from the Coronaviridae family. Using plaque assay, RT-qPCR and immunostaining, the adsorption and inactivation of the seasonal human coronavirus HCoV-229E and of 2 SARS-CoV-2 variants were demonstrated. The resulting data suggest that purified clinoptilolite-tuff could be used as an ingredient in new medical devices and/or pharmaceuticals to prevent or mitigate SARS-CoV-2 dissemination.

How standardization of the pre-analytical phase of both research and diagnostic biomaterials can increase reproducibility of biomedical research and diagnostics

Comparison of published biomedical studies shows that a large proportion are irreproducible, causing severe damage to society and creating an image of wasted investments. These observations are of course damaging to the biomedical research field, which is currently full of future promise. Precision medicine and disease prevention are successful, but are progressing slowly due to irreproducible study results. Although standardization is mentioned as a possible solution, it is not always clear how this could decrease or prevent irreproducible results in biomedical studies. In this article more insight is given into what quality, norms, standardization, certification, accreditation and optimized infrastructure can accomplish to reveal causes of irreproducibility and increase reproducibility when collecting biomaterials. CEN and ISO standards for the sample pre-analytical phase are currently being developed with the support of the SPIDIA4P project, and their role in increasing reproducibility in both biomedical research and diagnostics is demonstrated. In particular, it is described how standardized methods and quality assurance documentation can be exploited as tools for: 1) recognition and rejection of 'not fit for purpose' samples on the basis of detailed sample metadata, and 2) identification of methods that contribute to irreproducibility which can be adapted or replaced.

The disease relevance of human hepatocellular xenograft models: molecular characterization and review of the literature

In recent years a number of new therapeutics has been developed that were not general toxins and inhibitors of cell division like classical chemotherapeutics, but were designed to target a specific pathway. A prerequisite for this development was the comprehensive characterization of molecular alterations occurring in human hepatocellular carcinoma (HCC). However, while much knowledge of the molecular pathogenesis of human HCC has been gained, the model systems used to test the functional relevance of these alterations and applied for preclinical evaluation of drug candidates are still poorly characterized. In this paper, we reviewed the literature about several commonly used HCC cell lines and xenotransplantation models and present our own data on the molecular characterization of these. Results obtained demonstrate that it is important to have a sound knowledge of the specific molecular constitution of the experimental model and to carefully evaluate the functional status of the pathway of interest. For this reason, we make the gene expression profiles publicly available to help researchers making an informed decision about which model to use.

SAHA induces caspase-independent, autophagic cell death of endometrial stromal sarcoma cells by influencing the mTOR pathway

Endometrial stromal sarcomas are rare and molecular mechanisms involved in their pathogenesis are poorly understood. Covalent modifications of histone proteins, in particular de/acetylation of lysine residues, play an important role in the regulation of gene transcription in normal and neoplastic cells, but there are only limited data about these processes in solid mesenchymal tumours. We treated endometrial stromal sarcoma cells (ESS-1) and non-malignant human endometrial stromal cells (HESCs) with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor. SAHA was able to mediate the cell cycle and expression of genes related to the malignant phenotype of endometrial stromal tumours, eg p21(WAF1) and HDAC7. SAHA led to dose-dependent differentiation and death of ESS-1 cells but not of HESCs. Exposure of HESCs to SAHA resulted only in slightly decreased cell proliferation. SAHA also increased the p21(WAF1) expression and caused significant changes in the cell cycle by inhibiting the G1/S transition in ESS-1 cells. Recovery experiments indicated that these changes became irreversible when the tumour cells were treated with SAHA for longer than 24 h. In our experimental system, not apoptotic but autophagic processes were responsible for the cell death. Monodansyl cadaverine accumulation in treated ESS-1 cells and decreased expression of the mTOR and phospho-S6 ribosomal protein (S6rp) additionally supported this observation. Taken together, our study indicates that HDACs might be considered as potential drug targets in the therapy of stromal sarcomas and that SAHA might be a promising therapeutic agent for endometrial stromal sarcoma.

Intermediate filament cytoskeleton of the liver in health and disease

Intermediate filaments (IFs) represent the largest cytoskeletal gene family comprising approximately 70 genes expressed in tissue specific manner. In addition to scaffolding function, they form complex signaling platforms and interact with various kinases, adaptor, and apoptotic proteins. IFs are established cytoprotectants and IF variants are associated with >30 human diseases. Furthermore, IF-containing inclusion bodies are characteristic features of several neurodegenerative, muscular, and other disorders. Acidic (type I) and basic keratins (type II) build obligatory type I and type II heteropolymers and are expressed in epithelial cells. Adult hepatocytes contain K8 and K18 as their only cytoplasmic IF pair, whereas cholangiocytes express K7 and K19 in addition. K8/K18-deficient animals exhibit a marked susceptibility to various toxic agents and Fas-induced apoptosis. In humans, K8/K18 variants predispose to development of end-stage liver disease and acute liver failure (ALF). K8/K18 variants also associate with development of liver fibrosis in patients with chronic hepatitis C. Mallory-Denk bodies (MDBs) are protein aggregates consisting of ubiquitinated K8/K18, chaperones and sequestosome1/p62 (p62) as their major constituents. MDBs are found in various liver diseases including alcoholic and non-alcoholic steatohepatitis and can be formed in mice by feeding hepatotoxic substances griseofulvin and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). MDBs also arise in cell culture after transfection with K8/K18, ubiquitin, and p62. Major factors that determine MDB formation in vivo are the type of stress (with oxidative stress as a major player), the extent of stress-induced protein misfolding and resulting chaperone, proteasome and autophagy overload, keratin 8 excess, transglutaminase activation with transamidation of keratin 8 and p62 upregulation.

Preparation of adenovirus-polylysine-DNA complexes

This unit describes preparation of adenovirus-polylysine-DNA complexes, which is useful for transfection of DNA into a variety of cell types. A DNA complex is prepared with biotinylated adenovirus and streptavidin-polylysine, coupled to transferrin, and used to transfect cells. Several support protocols describe methods for adenovirus growth and purification, biotinylation, inactivation with psoralen, and quantitation of the adenovirus particles. Additional support protocols describes preparation of streptavidin-polylysine and transferrin-polylysine, necessary for the basic procedure. The DNA used for transfection must be free of lipopolysaccharide (LPS), and two methods for removing LPS are described. A more direct polylysine-virus linkage that is simple and requires no exotic reagents can be used for transfection. This protocol requires polylysine-modified adenovirus, prepared as described. An alternate protocol describes transfecting cells with free virus and DNA condensed with a polycation.

The Genome Austria Tissue Bank (GATiB)

In the context of the Austrian Genome Program, a tissue bank is being established (Genome Austria Tissue Bank, GATiB) which is based on a collection of diseased and corresponding normal tissues representing a great variety of diseases at their natural frequency of occurrence from a non-selected Central European population of more than 700,000 patients. Major emphasis is put on annotation of archival tissue with comprehensive clinical data, including follow-up data. A specific IT infrastructure supports sample annotation, tracking of sample usage as well as sample and data storage. Innovative data protection tools were developed which prevent sample donor re-identification, particularly if detailed medical and genetic data are combined. For quality control of old archival tissues, new techniques were established to check RNA quality and antigen stability. Since 2003, GATiB has changed from a population-based tissue bank to a disease-focused biobank comprising major cancers such as colon, breast, liver, as well as metabolic liver diseases and organs affected by the metabolic syndrome. Prospectively collected tissues are associated with blood samples and detailed data on the sample donor's disease, lifestyle and environmental exposure, following standard operating procedures. Major emphasis is also placed on ethical, legal and social issues (ELSI) related to biobanks. A specific research project and an international advisory board ensure the proper embedding of GATiB in society and facilitate international networking.

How a cell deals with abnormal proteins. Pathogenetic mechanisms in protein aggregation diseases

Defective protein folding is responsible for many diseases. Although these diseases seem to be quite diverse at the first glance, there is evidence for common pathogenetic principles. The basis of the pathological changes is the cell's inability to prevent protein misfolding, to revert misfolded proteins to normal or to eliminate misfolded proteins by degradation. This could result in deposition of potentially cytotoxic protein aggregates (protein aggregation diseases). Chronic degenerative diseases of the central nervous system (e.g. Alzheimer's and Parkinson's disease), the amyloidoses, but also chronic liver diseases, for example alcoholic and nonalcoholic steatohepatitis, belong to this category of disorders. This review highlights general pathogenic principles of protein aggregation diseases based on immunohistochemical and biochemical studies as well as observations in a mouse model for protein aggregation in the context of alcoholic and nonalcoholic steatohepatitis. The cellular defense mechanisms involved in protein quality control as well as the pathogenesis of protein aggregation diseases will be discussed.

Reduced expression of vacuole membrane protein 1 affects the invasion capacity of tumor cells

Vacuole membrane protein 1 (Vmp1) is described as a cancer-relevant cell cycle modulator, but the function of this protein and its mode of action in tumor progression are still unknown. In this study, we show that the VMP1 mRNA level is significantly reduced in kidney cancer metastases as compared to primary tumors. Further, VMP1 expression is also decreased in the invasive breast cancer cell lines HCC1954 and MDA-MB-231 as compared to the non-invasive cell lines MCF-12A, T-47D and MCF-7. We show for the first time that Vmp1 is a plasma membrane protein and an essential component of initial cell-cell contacts and tight junction formation. It interacts with the tight junction protein Zonula Occludens-1 and colocalizes in spots between neighboring HEK293 cells. Downregulation of VMP1 by RNAi results in loss of cell adherence, and increases the invasion capacity of the non-invasive kidney cancer cell line Caki-2. In conclusion, our findings establish Vmp1 to be a novel cell-cell adhesion protein and that its expression level determines the invasion and metastatic potential of cancer cells.

Biobank Governance: Trends and Perspectives

Biobanks are a challenge and topic for governance. Today, biobanks are identified as a biomedical scientific/infrastructural development that warrants a political/legal/ethical reaction with the goal to integrate biobanks into the preexisting fabric of regulation, medicine, law and society. Biobank governance is always a response to sociocultural challenges and requires the building of trust, acceptance, and careful political negotiation. Biobanks are regulated in networks of governance in which the state is one actor next to others, and the ordering and structuring of the interaction between biobanks, society, and politics operates through a variety of actors, on different levels and along particular rationalities. Such networks of governance reflect, to some extent, a postregulatory state in which governance has become a complicated architecture and field of action involving a multitude of forces and rationalities. Biobank governance is still a relatively new field of political-legal intervention and it will be crucial for the future of biobanks to establish governance regimes that appropriately link research with society and politics.

Are the Mallory bodies and intracellular hyaline bodies in neoplastic and non-neoplastic hepatocytes related?

Mallory bodies (MBs) and intracellular hyaline bodies (IHBs) are cytoplasmic hepatocellular inclusions that consist of aggregated proteins. MBs are characteristically associated with alcoholic and non-alcoholic steatohepatitis, but may also be found in chronic cholestatic and metabolic (eg copper intoxication) diseases and hepatocellular neoplasms, particularly hepatocellular carcinomas. IHBs have hitherto only been described in hepatocellular carcinoma cells. In the present study hepatocellular carcinomas (HCCs) and a case of idiopathic copper toxicosis were evaluated with respect to the presence and mutual relationship of MBs and IHBs. IHBs alone were present in 8.6%, MBs alone in 16.1% and both types of inclusion in 7.5% of HCCs. It is shown that IHBs may also occur in non-neoplastic hepatocytes in association with idiopathic copper toxicosis, together with MBs. In HCCs and idiopathic copper toxicosis, MBs and IHBs may be present within the same cell. Moreover, hybrid inclusions holding an intermediate position between MBs and IHBs regarding light microscopy, ultrastructure and composition exist. MBs and IHBs contain p62, a stress-inducible adapter protein, as the major constituent. In MBs p62 is associated with keratins, whereas classical IHBs lack keratins. Light microscopic, electron microscopic and immunohistochemical data suggest a close pathogenetic relationship between MBs and IHBs. Both types of inclusion are the result of over-expression and accumulation of the stress protein p62. If p62 is induced alone, or at least prevails, IHBs may arise by aggregation. However, if abnormal keratins are present in addition to p62, p62 associates and co-aggregates with keratins, finally leading to classical MBs.

[Alcoholic and non-alcoholic steatohepatitis]

Morphologic criteria of steatohepatitis are steatosis, ballooning of hepatocytes, often but not constantly associated with Mallory bodies, pericellular fibrosis and inflammation. Liver cirrhosis follows in about 20-50%. With respect to etiology an alcoholic and non-alcoholic type can be distinguished, the latter being a characteristic hepatic lesion associated with the metabolic syndrome (type II diabetes, insulin resistance, obesity, dyslipidemia). Ballooning of hepatocytes as well as Mallory body formation are associated with a disturbance of the keratin intermediate filament cytoskeleton. Mallory bodies are protein aggregates consisting of keratin (particularly keratin 8), p62, a stress-induced adapter protein involved in signal transduction pathways, heat shock proteins, and ubiquitin. Oxidative stress is involved in Mallory body formation. Major sources of oxidative stress in alcoholic and non-alcoholic steatohepatitis are the microsomal biotransformation system (cytochrome P-450) and the mitochondria, together with an impaired antioxidant defense system. Oxidative stress leads to misfolding/unfolding, abnormal phosphorylation of keratins and disturbance of keratin 8: keratin 18 ratio, and thus interferes with intermediate filament assembly. Moreover, impairment of cellular defense against abnormal proteins, i. e. chaperone action and proteasomal degradation, leads to the accumulation of abnormal aggregation--prone keratins (particularly keratin 8) which after ubiquitination associate with the stress-induced ubiquitin-binding protein p62 to form Mallory bodies. Thus, Mallory body formation resembles an "off-folding" protein response of the amyloid type. These pathogenetic principles of the human disease are supported by immunohistochemical and gene expression studies in experimental animals and by transfection experiments in tissue culture cells.

Prognostic relevance of tumour-associated macrophages and von Willebrand factor-positive microvessels in colorectal cancer

Tumour-associated macrophages (TAM) are involved in tumour angiogenesis and anti-tumour immune response. In colorectal cancer (CRC), an association of high microvascular density (MVD) and unfavourable prognosis has been reported by some investigators. However, heterogeneous patient groups were studied. We, therefore, analysed the correlation between TAM and MVD and the prognostic relevance of MVD, TAM and T lymphocyte infiltration for long-term survival in a homogeneous group of 70 patients with moderately differentiated cancers of the International Union Against Cancer (UICC) stages II and III, who did not receive chemotherapy. MVD was evaluated using immunohistochemistry with antibodies against CD34 and von Willebrand factor (vWF). TAM and T lymphocytes were visualised with antibodies against CD68 and CD3, respectively. Statistical analysis did not reveal a significant correlation between TAM and T lymphocyte numbers and MVD. Multivariate analysis of immunohistochemical data from all CRC patients and the subgroup of patients with UICC stage-II CRC identified TAM- and vWF-positive microvessel numbers as prognostically relevant markers. Low numbers of TAM- and high numbers of vWF-positive microvessels were associated with an unfavourable prognosis. In conclusion, TAM- and vWF-positive microvessel numbers may serve as independent prognostic markers for patients with UICC stage-II and -III CRC and may help to identify patients with an unfavourable prognosis.

Nonviral gene transfer into fetal mouse livers (a comparison between the cationic polymer PEI and naked DNA)

We investigated the efficacy and safety of the cationic polymer polyethylenimine (PEI) as a potential tool for intrauterine gene delivery into livers of fetal mice in the last trimester of pregnancy (E17.5). Using luciferase as a reporter gene, transferrin-conjugated and ligand-free PEI/DNA complexes (containing 3 microg DNA) with varying PEI-nitrogen/DNA-phosphate (N/P) ratios and different PEI forms, branched (800, 25 kDa) and linear (22 kDa), were compared with naked DNA. Transgene expression was measured 48 h after administration of PEI/DNA complexes or naked DNA. Highest luciferase activity (9.8 x 10(3) relative light units (RLU)/mg of tissue protein) was observed with ligand-free PEI22/DNA mixtures at N/P 6.0. In addition, this formulation was associated with very low toxicity as compared to the other PEI/DNA-injected groups. Using beta-galactosidase as a reporter gene, transfection of single, but also small, clusters of cells was demonstrated throughout the liver. Injection of 3 microg naked DNA resulted in an 11-fold lower transgene expression value (0.9 x 10(3) RLU/mg of tissue protein) as compared to PEI22/DNA complexes. However, the administration of higher concentrated naked DNA (9 microg) into fetal livers yielded expression levels of 3.2 x 10(4) RLU/mg of tissue protein, a more than three-fold increase compared to PEI22/DNA complexes. Furthermore, the gene transfer efficacy of concentrated naked DNA was approximately 40 times higher in fetuses than in adults (0.8 x 10(3) RLU/mg of tissue protein), indicating that fetal tissue is especially amenable to the uptake and expression of naked DNA.

Identification of tumor antigens in renal cell carcinoma by serological proteome analysis

We have investigated the suitability of proteomics for identification of tumor-associated antigens. First, we compared the proteomes of nontumorous kidney and renal cell carcinoma (RCC) by two-dimensional gel electrophoresis (2-DE) and silver staining. Protein patterns were markedly different (approximately 800 spots in RCCs versus approximately 1400 spots in kidney). 2-DE immunoblotting revealed five RCC-specific spots, reproducibly reactive with RCC-patient but not healthy donor control sera. Two of these antigens were isolated by preparative 2-DE, and identified by Edman sequencing of tryptic peptides. The first antigen, smooth muscle protein 22-alpha (SM22-alpha), is an actin-binding protein of unknown function predominantly expressed in smooth muscle cells. In situ hybridization revealed that SM22-alpha is not expressed in the malignant cells but in mesenchymal cells of the tumor stroma. The second antigen represents carbonic anhydrase I (CAI), an isoform usually not expressed in kidney. Interestingly, a different isoform (CAXII) has previously been identified by serological expression cloning as an antigen overexpressed in some RCCs. In additional assays, antibodies to recombinant CAI or SM22-alpha were detected in sera from 3/11 or 5/11 RCC patients, respectively, whereas sera from 13 healthy individuals did not react. In conclusion, serological proteome analysis may be a new tool for the identification of tumor-associated antigens.

Identification of tumor antigens in renal cell carcinoma by serological proteome analysis

We have investigated the suitability of proteomics for identification of tumor-associated antigens. First, we compared the proteomes of nontumorous kidney and renal cell carcinoma (RCC) by two-dimensional gel electrophoresis (2-DE) and silver staining. Protein patterns were markedly different (approximately 800 spots in RCCs versus approximately 1400 spots in kidney). 2-DE immunoblotting revealed five RCC-specific spots, reproducibly reactive with RCC-patient but not healthy donor control sera. Two of these antigens were isolated by preparative 2-DE, and identified by Edman sequencing of tryptic peptides. The first antigen, smooth muscle protein 22-alpha (SM22-alpha), is an actin-binding protein of unknown function predominantly expressed in smooth muscle cells. In situ hybridization revealed that SM22-alpha is not expressed in the malignant cells but in mesenchymal cells of the tumor stroma. The second antigen represents carbonic anhydrase I (CAI), an isoform usually not expressed in kidney. Interestingly, a different isoform (CAXII) has previously been identified by serological expression cloning as an antigen overexpressed in some RCCs. In additional assays, antibodies to recombinant CAI or SM22-alpha were detected in sera from 3/11 or 5/11 RCC patients, respectively, whereas sera from 13 healthy individuals did not react. In conclusion, serological proteome analysis may be a new tool for the identification of tumor-associated antigens.

[Alcoholic and nonalcoholic steatohepatitis. Histopathologic and pathogenetic considerations]

Alcoholic (ASH) and nonalcoholic (NASH) steatohepatitis show an almost identical morphology. Since the clinical picture is not characteristic, liver biopsy is still the diagnostic gold standard. ASH and NASH are morphologically characterized by a combination of steatosis, hepatocellular injury (ballooning degeneration, apoptosis, necrosis), perivenular and pericellular fibrosis, and inflammation (mostly neutrophils). A definitive differentiation of ASH and NASH is only possible by exclusion of alcohol abuse. Although NASH comprises a syndrome with a multifactorial etiology, adipositas seems to be the most constant associated causal factor. The pathogenesis of both diseases is still unclear. Clinical evidence and experimental studies suggest an important toxic role of reactive oxygen species (oxidative stress). According to our experience, ballooning of hepatocytes is a constant morphologic feature of ASH and NASH and already present in the early stages of disease. Ballooned cells often (but not always) contain Mallory bodies (alcoholic hyalin), which are irregular cytoplasmic inclusions consisting of keratins and nonkeratin components, including ubiquitin. Ballooning is associated with a disturbance and finally almost disappearance of the keratin-intermediate filament cytoskeleton. In our studies on the pathogenesis of ASH and NASH, we concentrated on these cytoskeletal alterations and Mallory body formation. It could be shown that in the early stages overexpression and hyperphosphorylation of keratins take place. Moreover, the 1:1 ratio of keratin type I (keratin 18) and type II (keratin 8) necessary for the assembly of intermediate filaments is disturbed and the equilibrium shifted toward keratin 8. Thus, the pool of soluble keratin 8 increases. The resulting keratin monomers are sensitive to misfolding and either degraded or aggregated as inclusion bodies. If the proteolytic capacity is impaired (e.g., by inhibition of the proteasomal system) in the chronically stressed cell aggregation prevails,finally leading to Mallory body formation. Convincing evidence exists on the basis of clinical and experimental studies that keratins exert a nonskeletal protective function in simple epithelia (e.g., liver cells). Disturbance of the keratin system may thus significantly contribute to cell damage.

[The increasing importance of tumor and tissue banks in the light of genomic and proteomic research]

Recent technological advances in genome and proteome research offer new perspectives for diagnosis and therapy. The DNA chip technology as well as high-resolution two-dimensional gel electrophoresis in combination with mass spectrometry is able to provide comprehensive information on gene and protein expression patterns, which allow insights into the dynamic and functional aspects of diseases. The application of these techniques depends on the availability of unfixed fresh or cryopreserved tissue with short ischaemia time. For this reason tissue banks are of increasing importance. The pathologist with his expertise and responsibility for histopathological diagnosis, plays a central role in the collection of the human tissues, in accordance with medical, legal and ethical standards, not only for diagnostic purposes, but also for research. The scientific value of a tissue bank is markedly increased if tissue samples are accompanied by detailed patient data as well as blood samples. Informed consent given by the patient is an essential requirement for the use of human tissue banks in biomedical research. The informed consent should not be restricted to scientific investigations but also include the potential commercial use of the data generated.

Identification of tumor antigens in renal cell carcinoma by serological proteome analysis

We have investigated the suitability of proteomics for identification of tumor-associated antigens. First, we compared the proteomes of nontumorous kidney and renal cell carcinoma (RCC) by two-dimensional gel electrophoresis (2-DE) and silver staining. Protein patterns were markedly different (approximately 800 spots in RCCs versus approximately 1400 spots in kidney). 2-DE immunoblotting revealed five RCC-specific spots, reproducibly reactive with RCC-patient but not healthy donor control sera. Two of these antigens were isolated by preparative 2-DE, and identified by Edman sequencing of tryptic peptides. The first antigen, smooth muscle protein 22-alpha (SM22-alpha), is an actin-binding protein of unknown function predominantly expressed in smooth muscle cells. In situ hybridization revealed that SM22-alpha is not expressed in the malignant cells but in mesenchymal cells of the tumor stroma. The second antigen represents carbonic anhydrase I (CAI), an isoform usually not expressed in kidney. Interestingly, a different isoform (CAXII) has previously been identified by serological expression cloning as an antigen overexpressed in some RCCs. In additional assays, antibodies to recombinant CAI or SM22-alpha were detected in sera from 3/11 or 5/11 RCC patients, respectively, whereas sera from 13 healthy individuals did not react. In conclusion, serological proteome analysis may be a new tool for the identification of tumor-associated antigens.

Effects of ursodeoxycholic and cholic acid feeding on hepatocellular transporter expression in mouse liver

BACKGROUND AND AIMS

Cholestasis is associated with retention of potentially toxic bile acids and alterations in hepatocellular transporter expression. Conversely, nontoxic ursodeoxycholic acid (UDCA) stimulates bile secretion and counteracts cholestasis. This study aimed to determine the effects of UDCA and cholic acid (CA) on the expression of hepatocellular transporters for bile acids (Ntcp, Bsep), organic anions (Oatp1, Mrp2), organic cations (Mdr1a/b), and phospholipids (Mdr2) in mouse liver.

METHODS

Bile flow/composition was analyzed in UDCA- or CA-fed mice. Transporter expression was studied by reverse-transcription polymerase chain reaction, Western blotting, and immunofluorescence microscopy.

RESULTS

UDCA had no effect on basolateral Ntcp and down-regulated Oatp1, whereas canalicular Bsep and Mrp2 were up-regulated. CA down-regulated basolateral Ntcp and Oatp1, whereas canalicular Bsep, Mrp2, and Mdr1a/b were up-regulated. Neither UDCA nor CA affected Mdr2 expression. Both UDCA and CA stimulated biliary bile acid and glutathione excretion, although only CA increased phospholipid and cholesterol excretion.

CONCLUSIONS

Down-regulation of basolateral and up-regulation of canalicular transporters in response to CA may represent a defense mechanism, in an attempt to prevent hepatocellular accumulation of potentially toxic bile acids. The therapeutic effects of UDCA may be caused in part by stimulation of canalicular transporter expression in the absence of hepatocellular toxicity.

Sequence of events in the assembly of Mallory body components in mouse liver: clues to the pathogenesis and significance of Mallory body formation

BACKGROUND/AIMS

Chronic intoxication of mice with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) or griseofulvin (GF) results in appearance of Mallory bodies (MBs) and alterations of the keratin cytoskeleton, which are reversible upon drug withdrawal but recur after readministration within 2-3 days.

METHODS

DDC- or GF-treated and recovered mice were reintoxicated with the original drugs but also colchicine and lumicolchicine. Cytoskeletal alterations of hepatocytes and MB formation were monitored by immunofluorescence microscopy using keratin, MB-specific antibodies, antibodies to phosphoepitopes and to HSP70. Keratin 8/18 mRNA expression and protein levels were determined by competitive reverse transcription-polymerase chain reaction, in situ-hybridization and western blotting.

RESULTS

Duration of pretreatment was important for the efficiency of MB triggering. Rapid increase of keratin 8/18 mRNA and proteins was found in all reintoxicated mice concomitant with MB formation, whereby keratin 8 prevailed over keratin 18. Keratins and a protein with heat shock characteristics (M(M) 120-1 antigen) were the earliest detectable MB components, whereas ubiquitination and phosphorylation followed later.

CONCLUSIONS

Overproduction of keratins is a major but not the only step responsible for MB formation. Additional components (e.g. M(M) 120-1 antigen) and excess of keratin 8 over keratin 18 are essential.

Hepatobiliary transporter expression in percutaneous liver biopsies of patients with cholestatic liver diseases

Reduced hepatobiliary transporter expression could explain impaired hepatic uptake and excretion of bile salts and other biliary constituents resulting in cholestasis and jaundice. Because little is known about alterations of hepatobiliary transport systems in human cholestatic liver diseases, it was the aim of this study to investigate such potential changes. Hepatic mRNA levels in hepatobiliary transport systems for bile salts (NTCP, BSEP), organic anions (OATP2, MRP2, MRP3), organic cations (MDR1), phospholipids (MDR3), and aminophospholipids (FIC1) were determined in 37 human liver biopsies and control livers by competitive reverse-transcription polymerase chain reaction (RT-PCR). Transporter tissue distribution was investigated by immunofluorescence microscopy. In patients with inflammation-induced icteric cholestasis (mainly cholestatic alcoholic hepatitis), mRNA levels of NTCP, OATP2, and BSEP were reduced by 41% (P <.001), 49% (P <.005), and 34% (P <.05) compared with controls, respectively. In addition, NTCP and BSEP immunostaining was reduced. MRP2 mRNA levels remained unchanged, but canalicular immunolabeling for MRP2 was also decreased. mRNA expression of MRP3, MDR1, MDR3, and FIC1 remained unchanged. In contrast to the alterations of transporter expression in inflammation-induced icteric cholestasis, transporter expression did not change in anicteric cholestasis caused by primary biliary cirrhosis (PBC) stages I and II. In conclusion, reduced expression of hepatobiliary transport systems for bile salts and other organic anions may contribute to inflammation-induced cholestasis in humans. Reduction of transporter gene expression can occur at the mRNA level as observed for NTCP, OATP2, and BSEP. However, reduced MRP2 immunostaining in the presence of conserved MRP2 mRNA levels suggests an additional role for posttranscriptional/posttranslational mechanisms.

Gene expression patterns associated with the metastatic phenotype in rodent and human tumors

Using subtractive technology, we have generated metastasis-associated gene expression profiles for rat mammary and pancreatic adenocarcinomas. Several genes whose expression is thought to be related to tumor progression such as c-Met, urokinase-type plasminogen activator receptor, ezrin, HMG-1, oncomodulin, cathepsin, and caveolin were thereby isolated. Half of the metastasis-associated clones showed no significant homology to genes with known function. Notably, several of the metastasis-associated clones were also expressed in metastatic lines but not in nonmetastatic lines of other tumor models. Furthermore, in situ hybridization using selected clones documents the relevance of these results for human cancer because strong expression in tumor cells including metastases was detected in human colorectal cancer samples and, to a lesser extent, in mammary cancer samples. These data support the concept that tumors express a "metastatic program" of genes.

The affinity of MCF7 breast cancer cells to hyaluronan substrates of different molecular weight and concentrations in an in vitro model

The affinity of MCF7 breast cancer cells to hyaluronan (HA) was investigated in an in vitro model. The cells form a tightly adhering monolayer on native HA with a concentration of 5 mg/ml. On native HA at higher concentrations the cells reduce their adhesion to the substrate in favor of increased intercellular bonds, resulting in a cluster-like aggregate that tends to detach from the substrate. Aggregate formation is accomplished after 12 h incubation. The phenomenon is independent of the CD44 receptor. Degradation of native HA by hyaluronidase abolishes aggregate formation even at high HA concentrations in favor of formation of a firmly adhering monolayer. This model may help to understand tumor spread on HA tissue structures and may explain therapy successes with hyaluronidase in tumor patients.

Cytokeratin 8 protects from hepatotoxicity, and its ratio to cytokeratin 18 determines the ability of hepatocytes to form Mallory bodies

In alcoholic hepatitis, a severe form of alcohol-induced toxic liver injury, as well as in experimental intoxication of mice with the porphyrinogenic drugs griseofulvin and 3,5-diethoxycarbonyl-1, 4-dihydrocollidine, hepatocytes form cytoplasmic protein aggregates (Mallory bodies; MBs) containing cytokeratins (CKs) and non-CK components. Here we report that mice lacking the CK8 gene and hence CK intermediate filaments in hepatocytes, but still expressing the type I partner, ie, the CK18 gene, do not form MBs but suffer from extensive porphyria and progressive toxic liver damage, leading to the death of a considerable number of animals (7 of 12 during 12 weeks of intoxication). Our observations show that 1) in the absence of CK8 as well as in the situation of a relative excess of CK18 over CK8 no MBs are formed; 2) the loss of CK8 is not compensated by other type II CKs; and 3) porphyria and toxic liver damage are drastically enhanced in the absence of CK8. Our results point to a protective role of CKs in certain types of toxic liver injury and suggest that MBs by themselves are not harmful to hepatocytes but may be considered as a product of a novel defense mechanism in hepatocytes.

Identification of p62, a phosphotyrosine independent ligand of p56lck kinase, as a major component of intracytoplasmic hyaline bodies in hepatocellular carcinoma

Intracytoplasmic hyaline bodies (IHBs) resemble a peculiar type of cytoplasmic inclusions in cells of hepatocellular carcinoma (HCC) which so far have escaped further characterization. In order to determine protein composition of IHBs we investigated tissue of a HCC containing numerous IHBs by immunohistochemistry and Western blot analysis using a large panel of different antibodies. Our studies revealed immunoreactivity of IHBs with the monoclonal antibodies SMI 31 and MPM-2 which recognize hyperphosphorylated epitopes present on paired helical filaments in Alzheimer's disease brains (SMI 31) and on proteins hyperphosphorylated by mitotic kinases (MPM-2), respectively. In two-dimensional Western blots of HCC extracts SMI 31 and MPM-2 antibodies detected a 62 to 65 kD protein with an isoelectric point around 4.5. Microsequencing identified this protein as p62, a recently identified phosphotyrosine-independent ligand of the SH2 domain of tyrosine kinase p56lck. Immunoreactivity of p62 protein spots with antibodies to phosphorylated epitopes (i.e. SMI 31 and MPM-2) suggest that p62 is highly phosphorylated in IHBs. This is the first report on accumulation of p62 as cellular inclusions and its association with human disease.

The tumor-associated shift in immunoglobulin G1/G2 is expressed at the messenger RNA level of peripheral blood B lymphocytes in patients with gynecologic malignancies

BACKGROUND

Previously, it could be demonstrated that human patients with malignant diseases of various tissues exhibited characteristic and highly significant changes in the serum patterns of immunoglobulin (Ig)G subclasses, consisting of a decrease in IgG1 and an increase in IgG2 relative to total IgG. The aim of the current study was to determine whether this phenomenon was detectable at the level of IgG-producing B lymphocytes.

METHODS

Using a competitive reverse transcriptase polymerase chain reaction specific to IgG1 and IgG2, the gene expression of these 2 IgG subclasses in peripheral B cells from 10 patients with carcinomas of various sites within the female reproductive tract and 10 healthy controls was quantitatively determined, in parallel with the concentrations of the respective serum proteins.

RESULTS

Absolute levels of IgG subclass messenger ribonucleic acid (mRNA) showed a slight but not significant decrease in IgG1 and an increase in IgG2 in patients with gynecologic malignancies. However, the ratio of IgG1 to IgG2 expression showed a highly significant (P < 0.001) decrease in tumor patients compared with healthy controls, and corresponded to the change in the ratio of IgG1 to IgG2 serum proteins.

CONCLUSIONS

These data suggest that the shifts in the serum patterns of IgG1 and IgG2 observed in patients with gynecologic malignancies are due to irregular biosynthesis of these IgG subclasses at the B-cell level.

Hepatocyte cytokeratins are hyperphosphorylated at multiple sites in human alcoholic hepatitis and in a mallory body mouse model

Alcoholic hepatitis (AH) is associated with cytokeratin 8 and 18 (CK8/18) accumulation as cytoplasmic inclusion bodies, termed Mallory bodies (MBs). Studies with MB mouse models and cultured hepatocytes suggested that CK8/18 hyperphosphorylation might be involved in MB formation. However, no data exist on phosphorylation of CK8/18 in human AH. In this study, antibodies that selectively recognize phosphorylated epitopes of CK8 or CK18 were used to analyze CK8/18 phosphorylation states in normal human and murine livers, human AH biopsies, and livers of 3,5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC)-intoxicated mice, the last serving as model for MB induction. Hepatocyte cytokeratins become hyperphosphorylated at multiple sites in AH and in DDC-intoxicated mice. Hyperphosphorylation of CK8/18 occurred rapidly, after 1 day of DDC intoxication and preceded architectural changes of the cytoskeleton. In long-term DDC-intoxicated mice as well as in human AH, MBs preferentially contain hyperphosphorylated CK8/18 as compared with the cytoplasmic cytokeratin intermediate filament network suggesting that CK8/18 hyperphosphorylation may play a contributing role in MB pathogenesis. Furthermore, the site-specific phosphorylation of cytokeratin in different stages of MB induction provides indirect evidence for the involvement of a variety of protein kinases known to be activated in stress responses, mitosis, and apoptosis.

Uptake of exogenous DNA via the skin

Easy accessibility makes the skin extremely attractive for therapeutic gene transfer, but this feature may be equally responsible for inadvertent DNA uptake. Therefore we studied lacZ reporter gene expression after epicutaneous and intracutaneous administration of naked DNA, lipofection and transferrinfection to intact, tape-stripped, and wound-healing skin of hairless mice. Gold particles coated with 1 microg pCMVnlslacZ were inoculated with a gene gun as a positive control. Beta-galactosidase expression by skin cells, i.e., keratinocytes of the upper epithelial layers and single cells in the upper dermis, determined by X-Gal histochemistry was not observed except after ballistic gene transfer. By polymerase chain reaction we detected lacZ DNA after skin bombardment up to 4 weeks. After intracutaneous and epicutaneous application to normal and tape-stripped skin of the various delivery systems lacZ DNA was detectable up to 1 week. Epicutaneous application of the delivery systems to wounded skin resulted in lacZ DNA detectability up to 48 h only. Reverse-transcriptase polymerase chain reaction indicated transcription of the reporter gene after particle bombardment and intracutaneous injection, up to 48 h, but not after epicutaneous application of either delivery system. The possibility of inadvertent uptake of exogeneous DNA by intact and tape-stripped skin is evidenced by the detection of reporter gene DNA after epicutaneous application of naked DNA and DNA complexed to cationic lipids or transferrin-polylysine (transferrinfection). However, the effects of the presence and persistence of foreign genes in the target cells are not clear yet.

Analysis of intracytoplasmic hyaline bodies in a hepatocellular carcinoma. Demonstration of p62 as major constituent

Intracytoplasmic hyaline bodies (IHBs) resemble inclusions in hepatocellular carcinoma cells, which so far have escaped further characterization. A relationship to Mallory bodies was suggested on the basis of light microscopy and filamentous ultrastructure. A hepatocellular carcinoma containing numerous IHBs was studied. Our studies revealed immunoreactivity of IHBs with the monoclonal antibodies SMI 31 and MPM-2, which recognize hyperphosphorylated epitopes present on paired helical filaments in Alzheimer's disease brains (SMI 31) or on diverse proteins hyperphosphorylated by mitotic kinases in the M-phase of the cell cycle (MPM-2). One- and two-dimensional gel electrophoresis of tumor extracts followed by immunoblotting with SMI 31 and MPM-2 antibodies revealed a major immunoreactive protein with an apparent molecular weight between 62 and 65 kd, which was resolved into several highly acidic (pH 4.5) protein components in two-dimensional gels. This protein was undetectable in non-neoplastic liver tissue. Sequence analysis identified the SMI 31 and MPM-2 immunoreactive material as p62, indicating that p62 is a major constituent of IHBs. p62 is an only recently discovered protein that is a phosphotyrosine-independent ligand of the SH2 domain of p56(lck), a member of the c-src family of cytoplasmic kinases. Moreover, p62 binds ubiquitin and may act as an adapter linking ubiquitinated species to other proteins. These features suggest a role of p62 in signal transduction and possibly also carcinogenesis. IHBs observed in the hepatocellular carcinoma cells presented are the first indications of a role of p62 in disease.

Functions of c-Jun in liver and heart development

Mice lacking the AP-1 transcription factor c-Jun die around embryonic day E13.0 but little is known about the cell types affected as well as the cause of embryonic lethality. Here we show that a fraction of mutant E13.0 fetal livers exhibits extensive apoptosis of both hematopoietic cells and hepatoblasts, whereas the expression of 15 mRNAs, including those of albumin, keratin 18, hepatocyte nuclear factor 1, beta-globin, and erythropoietin, some of which are putative AP-1 target genes, is not affected. Apoptosis of hematopoietic cells in mutant livers is most likely not due to a cell-autonomous defect, since c-jun-/- fetal liver cells are able to reconstitute all hematopoietic compartments of lethally irradiated recipient mice. A developmental analysis of chimeras showed contribution of c-jun-/- ES cell derivatives to fetal, but not to adult livers, suggesting a role of c-Jun in hepatocyte turnover. This is in agreement with the reduced mitotic and increased apoptotic rates found in primary liver cell cultures derived from c-jun-/- fetuses. Furthermore, a novel function for c-Jun was found in heart development. The heart outflow tract of c-jun-/- fetuses show malformations that resemble the human disease of a truncus arteriosus persistens. Therefore, the lethality of c-jun mutant fetuses is most likely due to pleiotropic defects reflecting the diversity of functions of c-Jun in development, such as a role in neural crest cell function, in the maintenance of hepatic hematopoiesis and in the regulation of apoptosis.

Immunotherapy of metastatic malignant melanoma by a vaccine consisting of autologous interleukin 2-transfected cancer cells: outcome of a phase I study

We performed a phase I trial to evaluate the safety and tolerability of repeated skin injections of IL-2-transfected autologous melanoma cells into patients with advanced disease. Cell suspensions, propagated from excised metastases, were IL-2 gene transfected by adenovirus-enhanced transferrinfection and X-irradiated prior to injection. Vaccine production was successful in 54% of the patients. Fifteen patients (37%) received two to eight skin vaccinations of either 3 x 10(6) (intradermal) or 1 x 10(7) (half intradermal, half subcutaneous) transfected melanoma cells per vaccination (secreting 140-17,060 biological response modifier program units of IL-2/10(6) cells/24 hr). Analyses of safety and efficacy were carried out in 15 and 14 patients, respectively. Overall, the vaccine was well tolerated. All patients displayed modest local reactions (erythema, induration, and pruritus) and some experienced flu-like symptoms. Apart from newly appearing (4 of 14) and increasing (5 of 14) anti-adenovirus and newly detectable anti-nuclear antibody titers (1 of 15), recipients developed de novo or exhibited increased melanoma cell-specific delayed-type hypersensitivity (DTH) reactions (8 of 15) and vitiligo (3 of 15) and showed signs of tumor regression (3 of 15). This supports the idea of a vaccine-induced or -amplified anti-cancer immune response. None of the patients exhibited complete or partial regressions, but five of them experienced periods of disease stabilization. Three of these individuals received more than the four planned vaccinations and their mean survival time was 15.7 +/- 3.5 months as compared to 7.8 +/- 4.6 months for the entire patient cohort. These data indicate that IL-2-producing, autologous cancer cells can be safely administered to stage IV melanoma patients and could conceivably be of benefit to patients with less advanced disease.

Altered microtubule-associated tau messenger RNA isoform expression in livers of griseofulvin- and 3,5-diethoxycarbonyl-1, 4-dihydrocollidine-treated mice

Tau proteins belong to the family of microtubule-associated proteins (MAPs), which so far have been mostly detected in neuronal cells. Different domains on the protein serve different functions. By alternative splicing, several mRNAs and tau isoforms are created from one gene, which contain these functionally important domains to various degrees, and thus differ in their microtubule-related properties. In the present article, several novel observations are reported. Tau mRNA and proteins have been identified and further characterized in mouse liver. It is shown on the basis of mRNA determinations that at least three tau isoforms differing particularly with respect to their amino-terminal domains are present in mouse liver. The major and predominant isoform (isoform 1) lacks portions encoded by exons 2 and 3, which are responsible for cross-talk of microtubules with their environment ("projection domain"). Moreover, mRNA encoding tau protein with four repeats of the microtubule binding domain predominate in embryonal as well as adult mouse liver in contrast to brain, in which a shift from the predominant three-repeat isoform to the four-repeat isoform characterizes the transition from the embryonic to the adult stage. Intoxication with griseofulvin (GF) or 3,5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC) significantly affects in a reversible manner the levels of tau mRNA as well as isoform ratios in mouse liver, but not in mouse brain. Tau mRNAs are significantly increased in intoxicated mouse livers. Moreover, a shift to isoform 1 lacking exons 2 and 3 occurs. However, the increase in liver tau protein was less than expected from increased mRNA levels, which could be the result of translational or posttranslational regulation. The consequences on microtubular function are as yet unclear, but impairment can be expected because the overexpressed tau mRNA isoform lacks the domain that mediates interaction of microtubules with their environment. On the other hand, the ratio of polymerized (microtubules) to nonpolymerized tubulin remained unaffected.

Expression of CD44 splice variant v10 in Hodgkin's disease is associated with aggressive behaviour and high risk of relapse

Expression of CD44 isoforms has been shown to correlate with the progression and prognosis of some malignant tumours. The aim of this study was to investigate the expression of CD44 standard (CD44s) and CD44 splice variants (CD44v) v5, v6, and v10 in lymph node specimens from patients with nodular sclerosing Hodgkin's disease (NSHD), with or without initial bone marrow involvement and with or without relapse. Specimens were studied by immunohistochemistry to determine CD44s and CD44v in Hodgkin- and Reed-Sternberg (HRS) cells. For validation of the immunohistochemical of detection of CD44v10 in paraffin-embedded samples, selected cases were analysed in parallel immunohistochemically using fresh frozen material and by reverse transcription-polymerase chain reaction (RT-PCR). There was high expression of CD44 isoforms containing the variant exon v10 selectively in HRS cells of patients with relapse within 2-3 years or with initial bone marrow involvement. In patients without relapse, however, no or only very few HRS cells were positive. These differences were statistically highly significant (p < or = 0.001), whereas evaluation of CD44s, CD44v5, and v6 expression revealed no marked differences. It is concluded that evaluation of CD44v10 expression could serve as a new prognostic marker in NSHD. These results are considered to be of sufficient importance to initiate a large multi-institutional study for confirmation; furthermore, they might suggest causal involvement of CD44v10 in the progression of NSHD.

CD44 and variants in melanocytic skin neoplasms

Expression of cell surface molecules that mediate cell-matrix and cell-cell interactions largely contributes to the ability of melanoma cells to migrate and spread beyond the primary site of the tumor. CD44, the principal cell-surface receptor for hyaluronate, and its numerous splice variants have been reported to play a crucial role in invasion and the metastatic process of different human neoplasms, including primary malignant melanoma (PMM). The aim of this study was to clarify which isoforms of CD44 (standard CD44 and CD44 variants) are distributed in PMM with a vertical tumor thickness of >1.4 mm. Staining of CD44 standard (CD44s) and splice variants was further examined for diagnostic and prognostic relevance in a panel of melanocytic skin lesions. Ten cases of PMM with Breslow >1.4 mm were analysed by immunohistochemistry using monoclonal antibodies specific for CD44s and the splice variants v3, v5, v6, v7, v7-8, and v10. In addition, using anti-CD44s, v5, and v6 antibodies, 55 melanocytic lesions, including dermal nevi (n=12), Clark nevi (dysplastic nevi) (CN; n=11), melanoma in situ (Mis; n=8), PMM (n=18), and cutaneous metastasis of malignant melanoma (cMMM; n=6) were assessed. Staining intensities were scored visually and evaluated by means of a staining index. In ten cases of PMM with a Breslow index >1.4 mm positive staining was ascertained for CD44s, v5 and for v6 in three cases. No staining was found for v3, v7, v7-8, and v10. Examination of CD44s, v5, and v6 in 55 melanocytic skin lesions revealed a high index for CD44s in all specimens and a weak staining of v5 in Mis; dermal nevi and CN did not stain for v5. However, in PMM and cMMM we found v5 to be strongly positive. The isoform v6 showed a variable index only in PMM, but without connection to established prognostic criteria. We conclude that CD44s and splice variants can not be regarded as indicators for tumor progression in malignant melanomas. However, v5 may potentially serve as a diagnostic marker for melanocytic skin lesions.

Lessons from keratin 18 knockout mice: formation of novel keratin filaments, secondary loss of keratin 7 and accumulation of liver-specific keratin 8-positive aggregates

Here, we report on the analysis of keratin 18 null mice. Unlike the ablation of K8, which together with K18 is expressed in embryonic and simple adult epithelia, K18 null mice are viable, fertile, and show a normal lifespan. In young K18 null mice, hepatocytes were completely devoid of keratin filaments. Nevertheless, typical desmosomes were formed and maintained. Old K18 null mice, however, developed a distinctive liver pathology with abnormal hepatocytes containing K8-positive aggregates. These stained positively for ubiquitin and MM120-1 and were identified as Mallory bodies, one hallmark of human alcoholic hepatitis. This is the first demonstration that the ablation of one keratin leads to the accumulation of its single partner. Another striking finding was the absence or drastic down regulation of K7 in several tissues despite its ongoing transcription. Moreover, K18 null mice revealed new insights in the filament-forming capacity of the tail-less K19 in vivo. Due to the unexpected secondary loss of K7, only K8/19 are expressed in the uterine epithelium of K18 null mice. Immunoelectron microscopy of this tissue demonstrated the presence of typical K8/19 IF, thus highlighting in vivo that K19 is a fully competent partner for K8.

Soluble CD44 v5 and v6 in serum of patients with breast cancer. Correlation with expression of CD44 v5 and v6 variants in primary tumors and location of distant metastasis

Primary breast cancers were shown to overexpress CD44 v5 and v6 at the plasma membrane. However, the clinical significance of this overexpression remains unclear. Overexpression of CD44 v5 and v6 in primary breast cancers was found to correlate with metastasis and poor prognosis by some investigators, yet this correlation could not be confirmed by others using different antibodies. In this study the influence of metastatic disease, the site of metastasis, and the amount of CD44 v5 and v6 expression in the primary tumor on serum levels of the soluble forms of CD44 v5 and v6 (sCD44 v5 and v6) in breast cancer patients was investigated. Soluble CD44 v5 and v6 serum levels were measured by enzyme linked immuno sorbent assay in a group of breast cancer patients who developed metastases in various organs and in another group of patients with single organ metastasis. For control, sCD44 v5 and v6 levels were measured in breast cancer patients who remained free of metastasis and in healthy blood donors. Expression of plasma membrane bound CD44 v5 and v6 in the primary tumors of the patients with metastasis in various organs was correlated to sCD44 v5 and v6 levels in serum. Furthermore the size of sCD44 v6 was analyzed by immunoblot using a monoclonal antibody directed against CD44 v6. When metastases were detected, sCD44 v5 and v6 serum levels were increased as compared to levels measured one month after tumor surgery in patients free of metastases (p= 0.0025 and p=0.0004). Six of 19 and 6 of 20 patients had sCD44 v5 and v6 serum levels above a cut-off level of 85 and 275 ng/mL, respectively. In these cases expression of CD44 v5 and v6 in the primary cancers was also elevated. Low sCD44 v5 and v6 serum levels were associated with weak expression of CD44 v5 and v6 in the respective primary cancers. As shown by statistical analysis of sCD44 v5 and v6 levels in 57 patients with single organ metastases, elevated sCD44 v6 levels but not sCD44 v5 levels were associated with metastases in liver or bone (p=0.0025). Immunoblot analysis of soluble CD44 proteins in serum revealed two CD44 v6 specific signals of approximately 120 and 170 kDa. Increased sCD44 v5 and v6 serum levels in patients with breast cancer were influenced by the amount of CD44 v5 and v6 expression in the primary tumor by the site of metastasis. Elevated sCD44 v6 serum levels were preferentially found in patients with metastases in liver or bone.

[Point mutations of the thyrotropin receptor gene in autonomously functioning thyroid gland nodules: correlation with clinical findings and morphology]

Seventeen autonomously functioning thyroid nodules (AFTN) were analyzed for the most frequent mutations of the thyrotropin (TSH) receptor gene at codons 619, 631, 632 and 633. DNA was extracted from formalin-fixed, paraffin-embedded samples from both nodules and surrounding tissue after micro- or macrodissection. A fragment of the TSH receptor gene (bp 1762-1976) encoding the third cytoplasmic loop and the sixth transmembranous domain was amplified by PCR. Screening for mutations at codons 619, 631, 632 and 633 was performed by restriction enzyme analysis using Asp 718, Hph I, Taq I and EcoR I, respectively. For verification, cases with a mutated restriction site were cloned and sequenced. Mutations were found in 3 AFTNs (18%): in 2 cases at codon 632 and in 1 case at codon 631. The 2 cases with a mutation at codon 632 harbored additional mutations at codon 599 and 640, respectively, detected by sequencing. Normal thyroid tissue outside the AFTNs did not harbor mutant TSH-receptor. Mutations occurred in patients with clinical and subclinical hyperthyroidism. Mutations were associated both with total (2 cases) and partial (1 case) suppression of the surrounding thyroid tissue as noted on the scinti scan. AFTNs with TSH-receptor mutation occurred as single nodules. All 3 nodules with mutations were classified histologically as nodular hyperplasia according to the criteria of the WHO. Although the number of cases is small, our data suggest that AFTNs are clinically and morphologically heterogenous. Since the most common TSH-receptor mutations occur only in a small subset of AFTNs other molecular genetic alterations may be involved in the development of AFTNs.

Expression of CD44 isoforms in human renal cell carcinomas

A series of 27 renal cell carcinomas 4 oncocytomas and 7 samples of tumour free kidney parenchyma were analysed immunohistochemically using eight different CD44 isoform-specific monoclonal antibodies. In normal kidney expression of CD44 isoforms (containing variant exons v6, v7/8 and v10) was found predominantly at the distal tubules. The majority of clear cell carcinomas investigated showed expression of variant exons v5, v7/8 and v10, but not v6. Lack of CD44v6 expression was confirmed by reverse transcription-polymerase chain reaction analysis. Carcinomas of the chromophilic cell type were almost completely devoid of CD44 expression, including the standard form CD44s. This study shows that there are statistically significant differences in the CD44 expression pattern of the two major histological subtypes of renal cell carcinomas (clear cell and chromophilic carcinomas). Moreover, the almost complete lack of CD44 expression in chromophilic carcinomas contrasts with carcinomas of other histogenetic origin investigated including stomach, breast and lung which express various CD44 isoforms abundantly.

IgG1--as the only subclass of human serum IgG--spontaneously undergoes O2(-)-induced, noncovalent self-aggregation upon storage at room temperature

An apparent gradual decrease of IgG1 serum levels of up to 40% occurs within 48 h of storage at room temperature. The effect does not concern any other IgG subclass, and is more pronounced in sera of smokers. A linear correlation was found between the extent of this "storage effect" and the initial concentration of IgG1, which rules out an enzymatic process following Michaelis-Menten kinetics. PAGE and Western blots of density gradient separated serum proteins revealed the presence of noncovalent self aggregates of IgG1 in stored sera. Addition of superoxide dismutase prevented both the formation of aggregates as well as the decay of IgG1 values. It is concluded that the instability of IgG1 is due to an enhanced propensity of this molecule to form self-aggregates, whereby O2(-)-radicals play a functional role. This mechanism, however, is not relevant to a previously detected selective decrease of relative IgG1 levels in sera of patients afflicted with malignant diseases of various tissue origin.

Elicitation of a systemic and protective anti-melanoma immune response by an IL-2-based vaccine. Assessment of critical cellular and molecular parameters

We have established a model for the immunologic rejection of melanoma cells. Using a receptor-mediated, adenovirus-augmented gene delivery system (transferrinfection) we have shown that, upon transfection with an IL-2 gene construct, MHC class I+/class II- murine M-3 cells lose their tumorigenicity in both athymic and euthymic mice. More importantly, we found that these melanoma cells, which produce high levels of IL-2, can be used to induce a long-lasting anti-tumor immune response in syngeneic euthymic DBA/2 mice but not in athymic animals. This immune response, which can also be elicited by coadministration of nonmodified, irradiated M-3 cells and IL-2-transduced fibroblasts, results in the rejection of a subsequent challenge with M-3 cells or, in the elimination of preexisting M-3 cancer cell deposits. We found that transfer of T cell-enriched, but not of T cell-depleted, splenocytes from immunized mice conferred protection against M-3 cells, but not against unrelated KLN 205 cancer cells. Transfer of either CD4+ or CD8+ T cells led to only partial protection against challenge with wild-type M-3 cells. Our further observations that T cell-enriched, but not T cell-depleted splenocytes of immunized animals are capable of tumor-specific lytic activity and that this activity resides in the CD8+ cell population are compatible with the assumption that MHC class I-restricted T cell cytotoxicity is a biologically relevant effector mechanism in this model. That other mechanisms also contribute to melanoma cell destruction is evidenced by the presence of large numbers of macrophages and granulocytes in addition to T cells at the challenge sites of immunized mice.

Elicitation of a systemic and protective anti-melanoma immune response by an IL-2-based vaccine. Assessment of critical cellular and molecular parameters

We have established a model for the immunologic rejection of melanoma cells. Using a receptor-mediated, adenovirus-augmented gene delivery system (transferrinfection) we have shown that, upon transfection with an IL-2 gene construct, MHC class I+/class II- murine M-3 cells lose their tumorigenicity in both athymic and euthymic mice. More importantly, we found that these melanoma cells, which produce high levels of IL-2, can be used to induce a long-lasting anti-tumor immune response in syngeneic euthymic DBA/2 mice but not in athymic animals. This immune response, which can also be elicited by coadministration of nonmodified, irradiated M-3 cells and IL-2-transduced fibroblasts, results in the rejection of a subsequent challenge with M-3 cells or, in the elimination of preexisting M-3 cancer cell deposits. We found that transfer of T cell-enriched, but not of T cell-depleted, splenocytes from immunized mice conferred protection against M-3 cells, but not against unrelated KLN 205 cancer cells. Transfer of either CD4+ or CD8+ T cells led to only partial protection against challenge with wild-type M-3 cells. Our further observations that T cell-enriched, but not T cell-depleted splenocytes of immunized animals are capable of tumor-specific lytic activity and that this activity resides in the CD8+ cell population are compatible with the assumption that MHC class I-restricted T cell cytotoxicity is a biologically relevant effector mechanism in this model. That other mechanisms also contribute to melanoma cell destruction is evidenced by the presence of large numbers of macrophages and granulocytes in addition to T cells at the challenge sites of immunized mice.

Generation of high-titer retroviral vectors following receptor-mediated, adenovirus-augmented transfection

A new procedure is described for the generation of high-titer, helper-free retrovirus vectors employing receptor-mediated, adenovirus-augmented transfection into a standard packaging cell line. Viral titers are increased 30-fold to 100-fold in transiently (> 10(5) infectious units per mL) and stable (> 10(7) infectious units per mL) transfected cells as compared with either CaPO4-mediated transfection or retroviral infection of a packaging cell line. Further, expression of the transduced genes was drastically increased in the transfected cells, but, as expected, there was no difference in transduction efficiency and gene expression in the infected target cells. The increases in viral titers were most likely due to the high number of stable, integrated copies of the vector plasmid DNA in the resulting packaging lines following G418 selection. In addition, experiments generating recombinant retroviruses from non-packaging cell lines are presented. The results suggest that this procedure may be of use to generate high-titer retrovirus vectors in packaging cell lines as well as in primary cells, thus providing a technical basis for in vivo gene transfer upon transplantation of these cells into various organs.