Thorsten Dohrmann

Effective Therapeutic Targeting of the Overexpressed HER-2 Receptor in a Highly Metastatic Orthotopic Model of Esophageal Carcinoma

This study aimed to determine the targeted efficacy of trastuzumab (Herceptin) on human epidermal growth factor receptor 2 (HER-2)-overexpressing metastatic esophageal cancer in an orthotopic mouse model. HER-2 overexpression and amplification of human esophageal primary and metastatic tumors were shown with HER-2–fluorescence in situ hybridization analysis and HER-2 immunostaining. Following orthotopic implantation with the HER-2–overexpressing OE19 human esophageal cancer cell line, mice were treated with trastuzumab. Sequential magnetic resonance imaging was used to monitor primary tumor and metastasis during treatment. After six weeks, a significant inhibition of primary tumor development was imaged in trastuzumab-treated animals in comparison with the control group. Trastuzumab treatment also led to a reduction of lymphatic metastasis. Thus, HER-2 targeted therapy with trastuzumab resulted in a significant primary tumor growth reduction as well as a decrease of lymph node metastases in the orthotopic model of metastatic esophageal carcinoma. The results of the present study suggest the clinical use of trastuzumab for HER-2–overexpressing esophageal cancer, which is a significant fraction of the patient population. Treatment of this highly treatment-resistant disease with trastuzumab in the adjuvant setting to prevent lymph node metastasis after primary tumor resection is suggested by the data in this report. Mol Cancer Ther; 9(7); 2037–45. ©2010 AACR.

Involvement of CXCR4 chemokine receptor in metastastic HER2-positive esophageal cancer.

A functional linkage of the structurally unrelated receptors HER2 and CXCR4 has been suggested for breast cancer but has not been evaluated for esophageal carcinoma. The inhibition of HER2 leads to a reduction of primary tumor growth and metastases in an orthotopic model of esophageal carcinoma. The chemokine receptor CXCR4 has been implicated in metastatic dissemination of various tumors and correlates with poor survival in esophageal carcinoma. The aim of this study was to investigate a correlation between the expression levels of HER2 and CXCR4 and to evaluate the involvemnent of CXCR4-expression in HER2-positive esophageal carcinoma. The effects of HER2-inhibition with trastuzumab and of CXCR4-inhibition with AMD3100 on primary tumor growth, metastatic homing, and receptor expression were evaluated in vitro and in an orthotopic model of metastatic esophageal carcinoma using MRI for imaging. The clinical relevance of HER2- and CXCR4-expression was examined in esophageal carcinoma patients. A significant correlation of HER2- and CXCR4-expression in primary tumor and metastases exists in the orthotopic model. Trastuzumab and AMD3100 treatment led to a significant reduction of primary tumor growth, metastases and micrometastases. HER2-expression was significantly elevated under AMD3100 treatment in the primary tumor and particularly in the metastases. The positive correlation between HER2- and CXCR4-expression was validated in esophageal cancer patients. The correlation of CXCR4- and HER2-expression and the elevation of HER2-expression and reduction of metastases through CXCR4-inhibition suggest a possible functional linkage and a role in tumor dissemination in HER2-positive esophageal carcinoma.

Complementary use of fluorescence and magnetic resonance imaging of metastatic esophageal cancer in a novel orthotopic mouse model

We describe the development of an aggressive orthotopic metastatic model of esophageal cancer, which is visualized in real time with combined magnetic resonance imaging (MRI) and fluorescence imaging. The aim of the study was to describe the development of a novel model of metastatic tumor disease of esophageal carcinoma and use this model to evaluate fluorescence and MRI in early detection of local and metastatic disease. The human esophageal adenocarcinoma cell line PT1590 was stably transfected with green fluorescent protein (GFP). Nude mice were orthotopically implanted with PT1590‐GFP cells. Orthotopic tumor growth as well as metastatic spread was examined by fluorescence imaging and high‐resolution MRI at defined intervals after orthotopic implantation. Highly aggressive novel fluorescent cell lines were isolated from metastatic tissues and put into culture. After implantation of these cells, 100% of the animals developed orthotopic primary tumors. In 83% of animals, metastatic spread to liver, lung and lymph nodes was observed. Primary tumor growth could be visualized with fluorescence imaging and with MRI with high correlation between the 2 methods. Fluorescence imaging allows fast, sensitive, and economical imaging of the primary and metastatic tumor without anesthesia. With MRI, anatomical structures are visualized more precisely and tumors can be more accurately localized to specific organs. This model should prove highly useful to understand esophageal carcinoma and to identify novel therapeutics for this treatment‐resistant disease.

ABO Blood Group IgM Isoagglutinins Interact with Tumor-Associated O-Glycan Structures in Pancreatic Cancer

Purpose: The ABO gene locus is associated with the risk of developing pancreatic ductal adenocarcinoma (PDAC) resulting in an increased incidence in individuals with non-O blood groups. Up to 90% of PDAC specimens display alterations in mucin type O-GalNAc glycosylation. Because aberrant O-GalNAc glycans (Tn and T antigen) are structurally related to blood group A and B glycans, we investigated the role of IgM isoagglutinins in PDAC. Experimental Design: Binding studies of IgM isoagglutinins toward blood group A, B, Tn antigen, and T antigen glycoconjugates from patients with PDAC and healthy individuals were conducted. Isoagglutinin titers and total IgM were compared between patients with PDAC and control group. An anti-A antibody was used for immunoprecipitation of aberrant O-glycosylated tumor proteins and subsequent mass spectromic analysis. Results: We found that IgM isoagglutinins bind blood group antigens, Tn and T glycoconjugates as well as tumor-derived glycoproteins. Blood group A isoagglutinins exhibited a strong binding toward blood group B antigen and T antigen, whereas blood group B showed binding to blood group A antigen and Tn antigen. Furthermore, we confirmed a decreased frequency in individuals with blood group O and observed a significant decrease of IgM isoagglutinin titers in PDAC sera compared with control sera, whereas total IgM levels were unaltered. We identified new PDAC-derived O-GalNAc glycoproteins by mass spectrometry using a blood group A-specific antibody. Conclusion: Our data elucidated a novel interaction of blood group IgM isoagglutinins and PDAC O-GalNAc glycoproteins that may contribute to the pathogenesis and progression of pancreatic cancer. Clin Cancer Res; 20(23); 6117–26. ©2014 AACR.

The T393C polymorphism of GNAS1 is a predictor for relapse and survival in resectable non-small cell lung cancer

INTRODUCTION The GNAS1 T393C single nucleotide polymorphism (T393C-SNP) correlates with Gαs mRNA stability and protein expression and augmented apoptosis. Genetic germ line variations as stable and reproducible markers potentially serve as prognostic marker in oncology. The aim of this study was to evaluate the potential prognostic value of T393C-SNP in complete resected non-small cell lung cancer (NSCLC). PATIENTS AND METHODS In total 163 Caucasian patients, who had been surgically treated for NSCLC between 1998 and 2010, were included in this study. Genotyping of peripheral blood cells was performed by polymerase chain reaction and digestion using the restriction enzyme FokI. The T393C-SNP was correlated with clinic-pathological parameters and survival. Chi-square test, Kaplan-Meier estimator and cox regression hazard model were used to assess the prognostic value of the T393C-SNP. RESULTS C-allele carriers had a higher recurrence rate (p=0.018) and a shorter disease-free survival compared to homozygous T-allele carriers (12.26 months vs. 44.65 months, p=0.009). The overall survival in homozygous C allele carriers was shorter (19.10 months vs. 53.95 months, p=0.019). Multivariate Cox regression identified the CC genotype as a negative independent prognostic factor for recurrence (hazard ratio 2.36, p=0.007) and survival (hazard ratio 2.51, p=0.008). CONCLUSION Determination of T393C-SNP preoperatively potentially allows allocation of NSCLC patients into different risk profiles and may influence the therapeutic strategy.

Cerebral Hemodynamics in Patients with Hemolytic Uremic Syndrome Assessed by Susceptibility Weighted Imaging and Four-Dimensional Non-Contrast MR Angiography.

Background and Purpose Conventional magnetic resonance imaging (MRI) of patients with hemolytic uremic syndrome (HUS) and neurological symptoms performed during an epidemic outbreak of Escherichia coli O104:H4 in Northern Europe has previously shown pathological changes in only approximately 50% of patients. In contrast, susceptibility-weighted imaging (SWI) revealed a loss of venous contrast in a large number of patients. We hypothesized that this observation may be due to an increase in cerebral blood flow (CBF) and aimed to identify a plausible cause. Materials and Methods Baseline 1.5T MRI scans of 36 patients (female, 26; male, 10; mean age, 38.2±19.3 years) were evaluated. Venous contrast was rated on standard SWI minimum intensity projections. A prototype four-dimensional (time resolved) magnetic resonance angiography (4D MRA) assessed cerebral hemodynamics by global time-to-peak (TTP), as a surrogate marker for CBF. Clinical parameters studied were hemoglobin, hematocrit, creatinine, urea levels, blood pressure, heart rate, and end-tidal CO2. Results SWI venous contrast was abnormally low in 33 of 36 patients. TTP ranged from 3.7 to 10.2 frames (mean, 7.9 ± 1.4). Hemoglobin at the time of MRI (n = 35) was decreased in all patients (range, 5.0 to 12.6 g/dL; mean, 8.2 ± 1.4); hematocrit (n = 33) was abnormally low in all but a single patient (range, 14.3 to 37.2%; mean, 23.7 ± 4.2). Creatinine was abnormally high in 30 of 36 patients (83%) (range, 0.8 to 9.7; mean, 3.7 ± 2.2). SWI venous contrast correlated significantly with hemoglobin (r = 0.52, P = 0.0015), hematocrit (r = 0.65, P < 0.001), and TTP (r = 0.35, P = 0.036). No correlation of SWI with blood pressure, heart rate, end-tidal CO2, creatinine, and urea level was observed. Findings suggest that the loss of venous contrast is related to an increase in CBF secondary to severe anemia related to HUS. SWI contrast of patients with pathological conventional MRI findings was significantly lower compared to patients with normal MRI (mean SWI score, 1.41 and 2.05, respectively; P = 0.04). In patients with abnormal conventional MRI, mean TTP (7.45), mean hemoglobin (7.65), and mean hematocrit (22.0) were lower compared to patients with normal conventional MRI scans (mean TTP = 8.28, mean hemoglobin = 8.63, mean hematocrit = 25.23). Conclusion In contrast to conventional MRI, almost all patients showed pathological changes in cerebral hemodynamics assessed by SWI and 4D MRA. Loss of venous contrast on SWI is most likely the result of an increase in CBF and may be related to the acute onset of anemia. Future studies will be needed to assess a possible therapeutic effect of blood transfusions in patients with HUS and neurological symptoms.

Laparoscopic and Conventional Limited Resection of the Gastroesophageal Junction with Isoperistaltic Jejunal Interposition

Limited en-bloc resection of the gastroesophageal junction includes complete removal of the esophageal segment with metaplastic mucosa, the lower esophageal sphincter, and a part of the lesser gastric curvature and formation of a neofundus. Because even early adenocarcinomas of the distal esophagus (T1b) seed lymph node metastases in up to 20 % of patients, removal of the lymph nodes of the lesser curvature, the hepatic and splenic arteries, the celiac trunk, the para-aortal region, and the inferior mediastinum is an essential part of the operation.

Abstract 1674: Significant reduction of primary growth and metastases through combined CXCR4 and HER-2 inhibition in an esophageal carcinoma orthotopic model

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Metastatic disease is the main cause of morbidity and mortality in esophageal carcinoma and the leading cause of death. While in the early stages surgical resection is the best therapeutic option, in late stages the conventional therapies surgery, chemotherapy, and radiation are limited. The expression of the chemokine receptor CXCR4 is known to be involved in metastatic homing and is associated with a poor prognosis in esophageal cancer patients. Trastuzumab treatment leads to significant tumor growth reduction in a model of HER-2 positive esophageal carcinoma. In the present report, we show the effects of the humanized monoclonal antibody trastuzumab, the CXCR4 inhibitor AMD3100 and their combined use in a metastastic orthotopic nude mouse model of esophageal cancer. Although both single therapies lead to tumor growth reduction the effect is further enhanced by their combination and leads to significant reduction of metastases. Tumor progression was monitored by non invasive MR imaging. High correlation between HER-2 and CXCR4 expression in primary tumor and metastatic organs was observed and might suggest a link between the chemokine receptor CXCR4 and receptor tyrosine kinase HER-2 in tumor progression and metastases. The results of this study suggest an effective treatment of metastatic prostate cancer by the combined use of drugs that target HER-2 and CXCR4. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1674. doi:10.1158/1538-7445.AM2011-1674