Palliative treatment of pancreatic cancer

Despite numerous diagnostic possibilities the early diagnosis of pancreatic cancer is still an exemption. Only 10-15% of patients are diagnosed at a stage where the tumor is resectable. Thus, most patients are treated with a palliative intention at first diagnosis. Palliative treatment comprises different therapeutic modalities involving radiochemotherapy and conventional chemotherapy. Chemotherapy, in particular, has been challenged by several new concepts involving combination regimens and the addition of targeted therapies to conventional therapeutic regimens. This review offers a critical presentation of current concepts in the palliative treatment of pancreatic cancer, discussing the problems of each and pointing to the development of new therapeutic strategies.

Second messenger regulation of mRNA for corticotropin-releasing factor

An understanding of how second messengers and their ligands are coupled to CRF gene activation is necessary if we are to understand the regulation of the CRF gene in physiological and pathological states. The protein kinase A, protein kinase C and glucocorticoid second messenger systems mediate most of the regulation of the CRF gene. In in vitro systems, CRF gene expression is stimulated 20-30-fold by activation of either the protein kinase A or the protein kinase C system. Glucocorticoid is able to inhibit stimulation via both pathways, but appears to be more effective in repressing activation mediated by protein kinase C. Glucocorticoid negative regulation requires the presence of glucocorticoid receptor possessing an intact DNA-binding domain, suggesting that this effect involves binding of the receptor to the CRF promoter. These in vitro studies should serve to guide investigators towards the possible mechanisms underlying CRF gene regulation in vivo.

Focal adhesion kinase mediates defects in the force-dependent reinforcement of initial integrin-cytoskeleton linkages in metastatic colon cancer cell lines

Micro-environmental clues, including the biophysical interpretation of the extracellular matrix, are critical to proliferation, apoptosis and migration. Here, we show that metastatic human colon cancer cell lines display altered matrix interaction. Interaction of colon cancer cells with collagen I depends on integrins (mainly alpha(1)/beta(1)) but metastatic cells display delayed spreading and reduced extension of lamellipodia. In addition, cells show defective strengthening of integrin-cytoskeleton linkages upon mechanical stimulation, as determined by laser trapping experiments and binding of large beads to the cell surface. However, adhesion to pliable surfaces is ameliorated in metastatic variants. These changes are caused by constitutive activation of focal adhesion kinase (FAK) and can be modulated by changing expression and/or activity of FAK via RNA-interference or expression of inhibitory constructs, respectively. In addition, consistent with defective strengthening of integrin-cytoskeleton linkages, metastatic cell lines show reduced random motility. Taken together these data suggest that constitutive activation of FAK causes defects in spreading, reinforcement of integrin-cytoskeleton linkages and migration and at the same time could ameliorate the adhesion of metastatic cells to suboptimal surfaces.

6-Thioguanine Nucleotide–Adapted Azathioprine Therapy Does Not Lead to Higher Remission Rates Than Standard Therapy in Chronic Active Crohn Disease: Results from a Randomized, Controlled, Open Trial

Background: A prospective randomized trial in patients with Crohn disease studied whether 6-thioguanine nucleotide (6-TGN) concentration–adapted azathioprine (AZA) therapy is clinically superior to a standard dose of 2.5 mg/kg/day AZA.

Methods: After 2 weeks of standard therapy, patients (n = 71) were randomized into standard (n = 32) or adapted-dose (n = 25) groups; 14 patients dropped out before randomization. In the adapted group, the AZA dose was adjusted to maintain 6-TGN concentrations between 250 and 400 pmol/8 × 108 erythrocytes (Ery). Response criteria were the number of patients in remission after 16 weeks without steroids (primary) and remission after 24 weeks, frequency of side effects, and quality of life (secondary).

Results: After 16 weeks, 14 of 32 (43.8%) patients in the standard group vs 11 of 25 (44%) in the adapted group were in remission without steroids (intent-to-treat analysis). After 24 weeks, 43.8% vs 40% were in remission. No significant differences were found concerning quality of life, disease activity, 6-TGN concentrations, AZA dose, or dropouts due to side effects. Sixty-six patients had a wild-type thiopurine S-methyltransferase (TPMT) genotype, with TPMT activities of 8 to 20 nmol/(mL Ery × h). Five patients (dropouts after randomization) were heterozygous, with TPMT activities <8 nmol/(mL Ery × h). 6-Methyl mercaptopurine (6-MMP) concentrations >5700 pmol/8 × 108 Ery were not associated with hepatotoxicity.

Conclusion: Standard and adapted dosing with the provided dosing scheme led to identical 6-TGN concentrations and remission rates. Adapted dosing had no apparent clinical benefit for patients with TPMT activity between 8 and 20 nmol/(mL Ery × h). Additionally, 6-MMP monitoring had no predictive value for hepatotoxicity.

Constitutive IKK2 activation in acinar cells is sufficient to induce pancreatitis in vivo

Activation of the inhibitor of NF-kappaB kinase/NF-kappaB (IKK/NF-kappaB) system and expression of proinflammatory mediators are major events in acute pancreatitis. However, the in vivo consequences of IKK activation on the onset and progression of acute pancreatitis remain unclear. Therefore, we modulated IKK activity conditionally in pancreatic acinar cells. Transgenic mice expressing the reverse tetracycline-responsive transactivator (rtTA) gene under the control of the rat elastase promoter were generated to mediate acinar cell-specific expression of IKK2 alleles. Expression of dominant-negative IKK2 ameliorated cerulein-induced pancreatitis but did not affect activation of trypsin, an initial event in experimental pancreatitis. Notably, expression of constitutively active IKK2 was sufficient to induce acute pancreatitis. This acinar cell-specific phenotype included edema, cellular infiltrates, necrosis, and elevation of serum lipase levels as well as pancreatic fibrosis. IKK2 activation caused increased expression of known NF-kappaB target genes, including mediators of the inflammatory response such as TNF-alpha and ICAM-1. Indeed, inhibition of TNF-alpha activity identified this cytokine as an important effector of IKK2-induced pancreatitis. Our data identify the IKK/NF-kappaB pathway in acinar cells as being key to the development of experimental pancreatitis and the major factor in the inflammatory response typical of this disease.

Thirty-eight-negative kinase 1 (TNK1) facilitates TNFα-induced apoptosis by blocking NF-κB activation

Thirty-eight-negative kinase 1 (TNK1) is a member of the ACK-family of nonreceptor tyrosine kinases and was originally cloned from CD34+/Lin-/CD38-hematopoietic stem/progenitor cells. The signaling pathways induced by TNK1 are largely unknown. Here, we report that expression and consequent activation of TNK1 enables tumor necrosis factor alpha (TNFalpha)-induced apoptosis by selectively inhibiting TNFalpha-induced activation of nuclear factor-kappaB (NF-kappaB). TNK1 has no effect on NF-kappaB DNA binding or the composition of the NF-kappaB complex; however, the kinase markedly prevents TNFalpha-induced NF-kappaB transactivation. TNK1 therefore acts as a novel molecular switch that can determine the properties of TNFalpha signaling and therefore cell death.

Sp1 is required for transforming growth factor-beta-induced mesenchymal transition and migration in pancreatic cancer cells

Transition from a sessile epithelial phenotype to a migrating mesenchymal phenotype is a crucial step in transforming growth factor-beta (TGF-beta)-induced pancreatic cancer cell migration and invasion. These profound morphologic and functional alterations are associated with characteristic changes in TGF-beta-regulated gene expression, defined by rapid repression of epithelial markers and a strong and sustained transcriptional induction of mesenchymal markers such as the intermediate filament vimentin. In this study, we have analyzed the role of the transcription factor Sp1 in TGF-beta-induced and Smad-mediated gene regulation during epithelial to mesenchymal transition (EMT) and migration of pancreatic cancer cells. Here, we show that Sp1 is required for TGF-beta-induced EMT, and that this function is especially mediated through transcriptional induction of vimentin. Our results emphasize the functional relevance of vimentin in TGF-beta-induced EMT because prevention of its induction strongly reduces cell migration. Altogether, this study helps to better understand the role of Sp1 in TGF-beta-induced progression of pancreatic cancer. It suggests that Sp1, via transcriptional induction of vimentin, cooperates with activated Smad complexes in mesenchymal transition and migration of pancreatic cancer cells upon TGF-beta stimulation.

[Reflux-associated nutcracker oesophagus in a 49-year-old patient with non-cardiac chest pain (NCCP)]

A 49-year-old woman was admitted to our department because of intermittent left-sided chest pain for the past 2 years. The patient reported an increasing frequency and duration of the symptoms which were independent from food intake, medication or physical exercises. A cardiac cause of the chest pain was excluded before admittance to our hospital. The initially performed upper endoscopy revealed a small oesophageal hiatal hernia but no signs of acute or chronic inflammation. Basal oesophageal manometry and pH monitoring confirmed the presence of a nutcracker oesophagus, defined by high-amplitude contractions of the distal oesophagus, in combination with a gastro-oesophageal reflux disease. The patient was treated with high-dose pantoprazole for 8 weeks before re-examination. Interestingly, the symptoms completely disappeared upon medication and the relief of the chest pain was accompanied by normalisation of the nutcracker oesophagus pattern. Thus, our observation provides evidence for a causative role of acid reflux in the pathophysiology of the nutcracker oesophagus and, in addition, suggests that effective acid suppression might be a useful therapeutic tool to deal with this painful motility disorder of the oesophagus.

Bile synthesis in rat models of inflammatory bowel diseases

BACKGROUND

A broad spectrum of hepatobiliary disorders are found in patients with inflammatory bowel diseases. The aim of the present work was to study interactions between gut and liver in experimental rat models of colitis and small bowel inflammation.

MATERIALS AND METHODS

Colitis was induced either by trinitrobenzene sulphonic acid or dextran sodium sulphate. Small-bowel inflammation was induced by indomethacin. Bile acid secretion, bile acid pool, and cholesterol 7-alpha hydroxylase were studied. Cholesterol 7-alpha hydroxylase protein expression was analysed in the microsomal liver fraction. As portal mediators released form the inflamed gut we measured lipopolysaccharide, tumour necrosis factor-alpha and interleukin-1beta in portal serum. The hepatic inflammatory response was evaluated by binding activity of nuclear factor-kappaB, activator protein-1 and alpha-2-macroglobulin.

RESULTS

Increased bile acid secretion, total bile acid content in gut and liver (bile acid pool size), and hepatic cholesterol 7-alpha hydroxylase protein and mRNA levels were found in the two colitis models associated with only a minor hepatic acute phase and cytokine response. In contrast, during indomethacin-induced small-bowel inflammation bile acid secretion, pool size, and cholesterol 7-alpha hydroxylase decreased in parallel to a strong hepatic cytokine and acute phase response.

CONCLUSIONS

Colitis without portal cytokine release and acute phase reaction shows an induction of bile acid secretion, pool size, and cholesterol 7-alpha hydroxylase. In contrast, intestinal inflammation after indomethacin treatment is associated with an acute phase response and a repression of bile acid synthesis.

A 25-year-old woman with a gastric GIST and a PET-positive epicardial tumor

BACKGROUND

A 25-year-old woman presented with a history of abdominal pain. Endoscopy of the upper gastrointestinal tract revealed a tumor that protruded into the prepyloric antrum. After resection, a 'high-risk' gastrointestinal stromal tumor was histologically confirmed.

INVESTIGATIONS

Endoscopy, endoscopic ultrasound, hemigastrectomy, [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT scan, histological examination, immunohistochemistry, cardiac MRI, high-resolution CT with electrocardiogram gating, CT angiography, and cardiac surgery.

DIAGNOSIS

Gastrointestinal stromal tumor, epicardial paraganglioma, and Carney's syndrome.

MANAGEMENT

Abdominal ultrasound and endoscopy combined with endoscopic ultrasound, annual FDG-PET/CT scan.

Cellular immune reaction in the pancreas is induced by constitutively active IkappaB kinase-2

BACKGROUND

Activation of the nuclear factor kappaB (NF-kappaB) system is a major event in acute and chronic inflammatory processes. NF-kappaB cascades are comprised of IkappaB kinases, IkappaBs and NF-kappaB dimers. Little is known of the individual roles of these proteins in organ specific inflammation. The aim of the present study was to analyse the consequences of ectopic IkappaB kinase-2 (IKK2) activation in the pancreas of mice.

METHODS

Transgenic mice were generated using an inducible genetic system (tet system) to conditionally overexpress a gain of function mutant of IKK2 (tetO-IKK2-EE) in the pancreas. To achieve transgene expression in the pancreas, these animals were crossed with CMV-rtTA mice that are known to express the rtTA protein in the pancreas.

RESULTS

In these double transgenic animals, doxycycline treatment induced expression of IKK2-EE (IKK2(CA)) in pancreatic acinar cells resulting in moderate activation of the IkappaB kinase complex, as measured by the immune complex kinase assay, and up to 200-fold activation of the transgene expression cassette, as detected by luciferase assay. IKK2(CA) expression in the pancreas had a mosaic appearance. Ectopic IKK2(CA) mostly activated the classical NF-kappaB pathway. The activation level of the NF-kappaB cascade induced by IKK2(CA) was considerably lower compared with that observed after supramaximal caerulein stimulation but still led to the formation of leucocyte infiltrates first observed after 4 weeks of doxycycline stimulation with a maximum after 8-12 weeks. The infiltrates were mainly composed of B lymphocytes and macrophages. Increased mRNA levels of tumour necrosis factor alpha and RANTES were detected in pancreatic acinar cells. However, only minor damage to pancreatic tissue was observed. A combination of supramaximal caerulein stimulation with induction of IKK2(CA) caused increased tissue damage compared with either IKK2(CA) or caerulein alone.

CONCLUSIONS

Our observations suggest that the role of IKK2 activation in pancreatic acini is to induce leucocyte infiltration, but at a moderate level of activation it is not sufficient to induce pancreatic damage in mice. The IKK2(CA) induced infiltrations resemble those observed in autoimmune pancreatitis, indicating a role for IKK2/NF-kappaB in this disease. IKK2(CA) in pancreatic acinar cells increases tissue damage of secretagogue induced experimental pancreatitis underlining the proinflammatory role of the IKK/NF-kappaB pathway in this disease.

The murine liver is a potential target organ for IL-19, IL-20 and IL-24: Type I Interferons and LPS regulate the expression of IL-20R2

BACKGROUND/AIMS

The biological functions of the recently discovered IL-10-related cytokines IL-19, IL-20, IL-22, IL-24 and their receptors IL-20R1, IL-20R2 and IL-22R are not clear. Therefore, the expression of these cytokines and their receptors in the hepatic acute phase response to LPS was analysed. Type I interferons have important immunomodulatory functions in bacterial infections. We investigated if they influence release and organ-specific expression of TNF, IL-6 and IL-10 and the responsiveness of liver to IL-10 related cytokines during the reaction to LPS in vivo.

METHODS

B6 and congenic IFNAR-/- mice were intraperitoneally injected with 5mg/kg LPS. Systemic release of cytokines was quantified by ELISA. Organ-specific expression of cytokines and their receptors was evaluated by (semi quantitative or quantitative) RT-PCR.

RESULTS

The cytokines IL-19, IL-22 and the IL-20R2 receptor subunit are up-regulated by LPS in the liver of normal mice. IFNalpha/beta enhance the secretion and expression of IL-6 and IL-10 during the response to LPS, but also the up-regulation of IL-20R2 expression.

CONCLUSIONS

We show that the liver is a potential target for IL-19, IL-20 and IL-24. During an LPS response, IFNalpha/beta influence cytokine secretion and expression and possibly the response to IL-19 and IL-24.

The bioactive lipid sphingosylphosphorylcholine induces differentiation of mouse embryonic stem cells and human promyelocytic leukaemia cells

Sphingosylphosphorylcholine (SPC) is the major component of high-density lipoproteins (HDL) in blood plasma. The bioactive lipid acts mainly via G protein coupled receptors (GPCRs). Similar to ligands of other GPCRs, SPC has multiple biological roles including the regulation of proliferation, migration, angiogenesis, wound healing and heart rate. Lysophospholipids and their receptors have also been implicated in cell differentiation. A potential role of SPC in stem cell or tumour cell differentiation has been elusive so far. Here we examined the effect of SPC on the differentiation of mouse embryonic stem (ES) cells and of human NB4 promyelocytic leukemia cells, a well established tumour differentiation model. Our data show that mouse embryonic stem cells and NB4 cells express the relevant GPCRs for SPC. We demonstrate both at the level of morphology and of gene expression that SPC induces neuronal and cardiac differentiation of mouse ES cells. Furthermore, SPC induces differentiation of NB4 cells by a mechanism which is critically dependent on the activity of the MEK-ERK cascade. Thus, the bioactive lipid SPC is a novel differentiation inducing agent both for mouse ES cells, but also of certain human tumour cells.

Pancreatic stellate cells are an important source of MMP-2 in human pancreatic cancer and accelerate tumor progression in a murine xenograft model and CAM assay

The effect of the characteristic desmoplastic reaction of pancreatic cancer on tumor progression is largely unknown. We investigated whether pancreatic stellate cells, which are responsible for the desmoplastic reaction, support tumor progression. Immunohistology revealed that matrix metalloproteinase-2 (MMP-2), which is suggested to promote pancreatic cancer progression, is present in stellate cells adjacent to cancer cells. In vitro, stellate cells exhibited a much higher basal expression of MMP-2 compared with cancer cells. Panc1-, MiaPaCa2- and SW850-conditioned media stimulated MMP-2 release of stellate cells as detected by zymography. Cancer cells expressed and released basigin [BSG, extracellular matrix metalloproteinase inducer (EMMPRIN), CD147], a glycoprotein that is known to stimulate MMP-2 in mesenchymal cells, as detected by immunostaining, western blot and reverse transcription-polymerase chain reaction. Tumor cell-conditioned medium and BSG purified by affinity chromatography from supernatants of cancer cells, but not supernatants depleted from BSG, stimulated expression of MMP-1 and MMP-2 of stellate cells as demonstrated by western blot and zymography. Moreover, the interaction of stellate cells and cancer cells promoted the invasiveness of Panc-1 cells in the chorioallantoic membrane assay and increased the weight of tumors induced by all carcinoma cell lines in nude mice by 2.1-3.7-fold. Our findings support the assumption that the interaction of stellate cells and cancer cells promotes progression of pancreatic cancer.

The tumor suppressor KLF11 mediates a novel mechanism in transforming growth factor beta-induced growth inhibition that is inactivated in pancreatic cancer

c-myc promoter silencing is a key step in epithelial cell growth inhibition by transforming growth factor beta (TGFbeta). During carcinogenesis, however, epithelial cells escape from c-myc repression and consequently become refractory to TGFbeta-mediated antiproliferation. Here, we assessed the role of the repressor, KLF11, in TGFbeta-induced growth inhibition in normal epithelial as well as pancreatic carcinoma cells. Endogenous KLF11 was stably down-regulated by RNA interference technology, and the functional consequences were studied by proliferation assays, reporter assays, DNA binding studies, and expression analyses. Coimmunoprecipitation and glutathione S-transferase pulldown assays were conducted to define KLF11-Smad3 interaction and U0126 was administered to examine the effects of the extracellular signal-regulated kinase (ERK)-mitogen-activated protein kinase on complex formation and c-myc promoter binding of KLF11 and Smad3 in pancreatic cancer cells. In TGFbeta-stimulated normal epithelial cells, nuclear KLF11, in concert with Smad3, binds to and represses transcription from the core region of the TGFbeta-inhibitory element (TIE) of the c-myc promoter. Disruption of KLF11-Smad3 interaction or small interfering RNA-mediated knockdown of endogenous KLF11 strongly diminishes Smad3-TIE promoter binding and repression, and consequently impairs TGFbeta-mediated growth inhibition. In pancreatic cancer cells with oncogenic Ras mutations, hyperactive ERK counteracts TGFbeta-induced c-myc repression and growth inhibition through at least two mechanisms, i.e., via disruption of KLF11-Smad3 complex formation and through inhibition of KLF11-Smad3 binding to the TIE element. Together, these results suggest a central role for KLF11 in TGFbeta-induced c-myc repression and antiproliferation and identifies a novel mechanism through which ERK signaling antagonizes the tumor suppressor activities of TGFbeta in pancreatic cancer cells with oncogenic Ras mutations.

[Hope and disappointment in cancer medicine]

Over the last few years fascinating new diagnostic procedures and innovative therapies with so-called "magic bullets" have been introduced into cancer medicine. However, hope stirred up by the introduction of these methods and therapies has to be rationally evaluated with regard to their success, their implementation in medical care, their compatibility with the patient's preferences and their benefit, also with regard to their high costs.

[Fulminant pancreatitis--internal point of view]

In acute pancreatitis pancreatic necrosis and involvement of different organ systems determine clinical course and severity. There is no method to predict the outcome of acute pancreatitis at the beginning of the disease. If there is evidence for severe pancreatitis, an immediate intensive care of all organ systems is needed, to avoid complications. Besides clinical signs, serum CRP is the most valuable parameter to define severity. According to present knowledge, a CT scan is only needed in sepsis or multiorgan failure. Non-invasive ventilation should be started early in case of hypoxia. Up to now, no general benefit was detected for antibiotic prophylaxis or enteral nutrition.

Nerve growth factor secretion in cultured enteric glia cells is modulated by proinflammatory cytokines

The enteric nervous system is composed of neurones and glial cells. These enteric glia cells (EGC) appear to be essential for the maintenance of gut homeostasis and mucosal integrity. Neurotrophin nerve growth factor (NGF) also plays an important role for the gut integrity by regulating sensory and inflammatory processes in the intestines. Here, we demonstrate EGCs as one source of NGF and show increased levels of NGF mRNA/protein and tropomyosin receptor kinase A (TrkA) mRNA in cultured EGCs upon stimulation with proinflammatory cytokines and lipopolysaccharides. NGF is continuously secreted from cultured EGCs and proinflammatory cytokines and lipopolysaccharides stimulate the secretion of this neurotrophin in a time- and dose- dependent manner, whereas interleukin-4 had no effect on NGF expression. Furthermore, NGF secretion was sustained for more than 12 h after withdrawal of the proinflammatory cytokines, suggesting the involvement of transcriptional and/or translational processes. Thus, the release of proinflammatory cytokines can increase NGF secretion by EGCs and leads to a higher expression of TrkA in EGCs. NGF, in turn, can increase visceral sensitivity and, on the other hand, appears to improve gut inflammation. Therefore, NGF secreting EGCs may play a key role in modulating visceral sensitivity and might be involved in inflammatory processes of the gut.