Michael Bitzer

Phase III Comparison of Preoperative Chemotherapy Compared With Chemoradiotherapy in Patients With Locally Advanced Adenocarcinoma of the Esophagogastric Junction

PURPOSE Preoperative chemotherapy is an accepted standard in the treatment of localized esophagogastric adenocarcinoma. Adding radiation therapy to preoperative chemotherapy appears promising, but its definitive value remains unknown. PATIENTS AND METHODS Patients with locally advanced (uT3-4NXM0) adenocarcinoma of the lower esophagus or gastric cardia were randomly allocated to one of two treatment groups: induction chemotherapy (15 weeks) followed by surgery (arm A); or chemotherapy (12 weeks) followed by chemoradiotherapy (3 weeks) followed by surgery (arm B). Primary outcome was overall survival time. A total of 354 patients were needed to detect a 10% increase in 3-year survival from 25% to 35% by addition of radiation therapy. The study was prematurely closed due to low accrual. RESULTS The median observation time was 46 months. A total of 126 patients were randomly assigned and 119 eligible patients were evaluated. The number of patients undergoing complete tumor resection was not different between treatment groups (69.5% v 71.5%). Patients in arm B had a significant higher probability of showing pathologic complete response (15.6% v 2.0%) or tumor-free lymph nodes (64.4% v 37.7%) at resection. Preoperative radiation therapy improved 3-year survival rate from 27.7% to 47.4% (log-rank P = .07, hazard ratio adjusted for randomization strata variables 0.67, 95% CI, 0.41 to 1.07). Postoperative mortality was nonsignificantly increased in the chemoradiotherapy group (10.2% v 3.8%; P = .26). CONCLUSION Although the study was closed early and statistical significance was not achieved, results point to a survival advantage for preoperative chemoradiotherapy compared with preoperative chemotherapy in adenocarcinomas of the esophagogastric junction.

Natural Killer Cell–Mediated Lysis of Hepatoma Cells via Specific Induction of NKG2D Ligands by the Histone Deacetylase Inhibitor Sodium Valproate

Natural killer (NK) cells as components of the innate immunity substantially contribute to antitumor immune responses. However, the tumor-associated ligands engaging activating NK cell receptors are largely unknown. An exception are the MHC class I chain-related molecules MICA and MICB and the UL16-binding proteins (ULBP) which bind to the activating immunoreceptor NKG2D expressed on cytotoxic lymphocytes. A therapeutic induction of NKG2D ligands that primes cancer cells for NK cell lysis has not yet been achieved. By microarray studies, we found evidence that treatment of human hepatocellular carcinoma cells with the histone deacetylase inhibitor (HDAC-I) sodium valproate (VPA) mediates recognition of cancer cells by cytotoxic lymphocytes via NKG2D. VPA induced transcription of MICA and MICB in hepatocellular carcinoma cells, leading to increased cell surface, soluble and total MIC protein expression. No significant changes in the expression of the NKG2D ligands ULBP1-3 were observed. The induction of MIC molecules increased lysis of hepatocellular carcinoma cells by NK cells which was abolished by addition of a blocking NKG2D antibody. Importantly, in primary human hepatocytes, VPA treatment did not induce MIC protein expression. Taken together, our data show that the HDAC-I VPA mediates specific priming of malignant cells for innate immune effector mechanisms. These results suggest the clinical evaluation of HDAC-I in solid tumors such as hepatocellular carcinoma, especially in combination with immunotherapy approaches employing adoptive NK cell transfer.

Physical Properties of Endovascular Stents: An Experimental Comparison

PURPOSE Different endovascular stent types (AVE Bridge, AVE Bridge X, Memotherm, Palmaz Large, Palmaz Medium, Palmaz-Schatz Long-Medium, Perflex, S.MA.R.T., Symphony, and Wall-stent) of 4 cm length and 8 mm diameter were subjected to standardized physical tests. MATERIALS AND METHODS The metal mass of each stent was assessed by weighing. The balloon-expandable stents were pneumatically tested for hoop strength. In self-expanding stents, radial resistive force and chronic outward force were determined with use of a loop test. Stent delivery system pushability was assessed in a crossover model. Stent radiopacity was analyzed quantitatively. RESULTS The hoop strength of the balloon-expandable stents ranged from 15.8 N/cm (Perflex) to 28.9 N/cm (AVE Bridge X). The stent weight increased with greater hoop strength (Perflex, 0.046 g/cm vs. AVE Bridge X, 0.061 g(cm). The self-expanding stents had a radial resistive force between 0.39 N/cm (Wallstent) and 1.7 N/cm (Smart). The flexible balloon-expandable stents showed pushability values between 0.13/N (AVE Bridge) and 0.20/N (Perflex). The self-expanding stents had flexibilities between 0.13/N (Memotherm) and 0.24/N (Symphony). Radiopacity assessed with use of a phantom simulating the iliac region ranged from 92 (Palmaz Large) to 115 (AVE Bridge) on a 256-point gray scale (0 = black, 256 = white). CONCLUSIONS There is no stent with ideal physical properties. However, depending on the characteristics of the arterial lesion to be treated, the most appropriate stent can be chosen.

HDAC inhibitor treatment of hepatoma cells induces both TRAIL‐independent apoptosis and restoration of sensitivity to TRAIL

Hepatocellular carcinoma (HCC) displays a striking resistance to chemotherapeutic drugs or innovative tumor cell apoptosis–inducing agents such as tumor necrosis factor–related apoptosis‐inducing ligand (TRAIL). Recently, we found 2 histone deacetylase inhibitors (HDAC‐I), valproic acid and ITF2357, exhibiting inherent therapeutic activity against HCC. In TRAIL‐sensitive cancer cells, the mechanism of HDAC‐I–induced cell death has been identified to be TRAIL‐dependent by inducing apoptosis in an autocrine fashion. In contrast, in HCC‐derived cells, a prototype of TRAIL‐resistant tumor cells, we found a HDAC‐I‐mediated apoptosis that works independently of TRAIL and upregulation of death receptors or their cognate ligands. Interestingly, TRAIL resistance could be overcome by a combinatorial application of HDAC‐I and TRAIL, increasing the fraction of apoptotic cells two‐ to threefold compared with HDAC‐I treatment alone, whereas any premature HDAC‐I withdrawal rapidly restored TRAIL resistance. Furthermore, a tumor cell–specific downregulation of the FLICE inhibitory protein (FLIP) was observed, constituting a new mechanism of TRAIL sensitivity restoration by HDAC‐I. In contrast, FLIP levels in primary human hepatocytes (PHH) from different donors were upregulated by HDAC‐I. Importantly, combination HDAC‐I/TRAIL treatment did not induce any cytotoxicity in nonmalignant PHH. In conclusion, HDAC‐I compounds, exhibiting a favorable in vivo profile and inherent activity against HCC cells, are able to selectively overcome the resistance of HCC cells toward TRAIL. Specific upregulation of intracellular FLIP protein levels in nonmalignant hepatocytes could enhance the therapeutic window for clinical applications of TRAIL, opening up a highly specific new treatment option for advanced HCC. (HEPATOLOGY 2006;43:425–434.)

Angiogenesis and Brain Oedema in Intracranial Meningiomas: Influence of Vascular Endothelial Growth Factor

Summary The correlation between angiographic neovascularization, peritumoural brain oedema (PTBOe) and the expression of vascular endothelial growth factor (VEGF) , was analysed in 30 patients with intracranial meningiomas.Pre-operative angiograms were examined for the existence of either an exclusively dural tumour blush or an additionally pial tumour supply from cerebral arteries. Furthermore the presence of macroscopic tumour-neovascularization and dysplastic changes of tumour-draining cerebral veins was evaluated. VEGF expression was investigated on histological tissue samples, using immunohistochemical techniques. VEGF immunohistochemistry and neuroradiological evaluations were performed in double blind fashion. Tumour volume and the amount of oedema were calculated by computerized tomography (CT) or magnetic resonance imaging (MRI). The oedema-tumour volume ratio was defined as oedema index (OeI).Compared to VEGF-negative meningiomas, tumours with striking VEGF staining revealed a significant higher mean oedema index (OeI=4,2 vs. OeI=1,5; p<0.018), and a higher oedema incidence (91,7% vs. 44,4%; p<0.046). Equally, meningiomas with additionally tumour supply from cerebral arteries were associated with a significant higher mean OeI (OeI=4.1 vs. OeI=1.2; p<0.01) and oedema incidence (94,7% vs. 20,0%; p<0,0023) than meningiomas with exclusively tumour supply from dural arteries. All meningiomas with striking VEGF-expression were associated with vascular tumour supply from cerebral arteries, but VEGF-negative tumours only in 50% (p<0.029). These data suggest a link between VEGF-expression, arterial tumour supply and peritumoural brain oedema. The development of tumour supply from cerebral arteries may be important for formation of meningioma-related oedema. Therefore, VEGF may represent a potent mediator in the evolution of this type of vascularization in meningiomas.

Epigenetic combination therapy as a tumor-selective treatment approach for hepatocellular carcinoma.

Innovative epigenetic therapeutics comprise histone deacetylase inhibitors (HDAC‐I) and demethylating agents (DA). It was recently found that HDAC‐I compounds exhibit profound therapeutic activities against hepatocellular carcinoma (HCC). A comprehensive preclinical investigation was performed on the potential of a combined HDAC‐I/DA epigenetic regimen for the highly chemotherapy‐resistant HCC entity.

Diffusion-Weighted MRI of Advanced Hepatocellular Carcinoma During Sorafenib Treatment: Initial Results

OBJECTIVE The objective of our study was to evaluate signal changes of advanced hepatocellular carcinoma in diffusion-weighted MRI in the early-response monitoring of oral therapy with the multikinase inhibitor sorafenib. CONCLUSION Hepatocellular carcinoma lesions exhibit characteristic but unusual apparent diffusion coefficient (ADC) changes during sorafenib therapy, consisting of early decrease in ADC after therapy onset followed by a reincrease. The ADC changes seem to reflect the underlying pathophysiologic mechanisms in tumor necrosis (most probably hemorrhagic) induced by this novel targeted agent early after therapy onset and may indicate tumor reactivation in the later follow-up period.

Resveratrol as a Pan-HDAC Inhibitor Alters the Acetylation Status of Jistone Proteins in Human-Derived Hepatoblastoma Cells

The polyphenolic alcohol resveratrol has demonstrated promising activities for the prevention and treatment of cancer. Different modes of action have been described for resveratrol including the activation of sirtuins, which represent the class III histone deacetylases (HDACs). However, little is known about the activity of resveratrol on the classical HDACs of class I, II and IV, although these classes are involved in cancer development or progression and inhibitors of HDACs (HDACi) are currently under investigation as promising novel anticancer drugs. We could show by in silico docking studies that resveratrol has the chemical structure to inhibit the activity of different human HDAC enzymes. In vitro analyses of overall HDAC inhibition and a detailed HDAC profiling showed that resveratrol inhibited all eleven human HDACs of class I, II and IV in a dose-dependent manner. Transferring this molecular mechanism into cancer therapy strategies, resveratrol treatment was analyzed on solid tumor cell lines. Despite the fact that hepatocellular carcinoma (HCC) is known to be particularly resistant against conventional chemotherapeutics, treatment of HCC with established HDACi already has shown promising results. Testing of resveratrol on hepatoma cell lines HepG2, Hep3B and HuH7 revealed a dose-dependent antiproliferative effect on all cell lines. Interestingly, only for HepG2 cells a specific inhibition of HDACs and in turn a histone hyperacetylation caused by resveratrol was detected. Additional testing of human blood samples demonstrated a HDACi activity by resveratrol ex vivo. Concluding toxicity studies showed that primary human hepatocytes tolerated resveratrol, whereas in vivo chicken embryotoxicity assays demonstrated severe toxicity at high concentrations. Taken together, this novel pan-HDACi activity opens up a new perspective of resveratrol for cancer therapy alone or in combination with other chemotherapeutics. Moreover, resveratrol may serve as a lead structure for chemical optimization of bioavailability, pharmacology or HDAC inhibition.

Early MRI response monitoring of patients with advanced hepatocellular carcinoma under treatment with the multikinase inhibitor sorafenib

BackgroundNew therapeutic principles in clinical oncology require the adjustment of response criteria to govern therapy decisions. For advanced hepatocellular carcinoma (HCC) a new era has recently begun by the approval of the multikinase inhibitor sorafenib. As a unique feature, HCC usually develops in a diseased liver and current imaging technologies employing classical response criteria have not been prospectively evaluated for this new treatment.MethodsMRI signal patterns were assessed in 21 advanced HCC patients receiving sorafenib. MRI was performed at baseline and in short-term intervals thereafter. Signal changes under therapy on T1WI, T2WI and post-gadolinium images including necrosis volume and its ratio to the entire tumor volume were compared to baseline imaging. To assess the association between the categorical variables, Fishers exact tests were applied for a statistical analysis. Survey time ranged from 2–65 weeks, and a total of 39 target lesions were evaluated.ResultsSignal abnormalities during sorafenib therapy were disclosed by T1WI and T2WI in 15/21 patients. The predominant tumor signal change was hyperintensity on both T1WI and T2WI. Interestingly, most patients developed MRI signal changes within 4 weeks of therapy; in contrast, two non-responders did not show any signal alteration at follow-up. Under therapy, 16/21 patients presented with new or progressive necrosis, whereas 7 patients achieved temporarily >75% tumor necrosis under sorafenib. Significantly associated MRI variables were increase in T1WI signal and tumor necrosis (p = 0.017) as well as increase of tumor necrosis with an elevated ratio of necrotic to vital tumor areas (p = 0.002). Remarkably, some (3/13) of the patients developing necrotic tumor areas showed a relevant (>20%) increase in tumor volume, which should be considered in the assessment of imaging studies.ConclusionAs sorafenib induces early intralesional necrosis with profound changes in T1WI/T2WI MRI signal intensities and measurable necrotic tumor areas in most HCC patients, early MRI-based evaluation could pave the way for its rationale and cost-effective application.

Sendai virus vectors as an emerging negative‐strand RNA viral vector system

The power to manipulate the genome of negative‐strand RNA viruses, including the insertion of additional non‐viral genes, has led to the development of a new class of viral vectors for gene transfer approaches. The murine parainfluenza virus type I, or Sendai virus (SeV), has emerged as a prototype virus of this vector group, being employed in numerous in vitro as well as animal studies over the last few years. Extraordinary features of SeV are the remarkably brief contact time that is necessary for cellular uptake, a strong but adjustable expression of foreign genes, efficient infection in the respiratory tract despite a mucus layer, transduction of target cells being independent of the cell cycle, and an exclusively cytoplasmic replication cycle without any risk of chromosomal integration.