Johannes Klose

Transgenic expression of human heme oxygenase-1 in pigs confers resistance against xenograft rejection during ex vivo perfusion of porcine kidneys

Petersen B, Ramackers W, Lucas‐Hahn A, Lemme E, Hassel P, Queißer A‐L, Herrmann D, Barg‐Kues B, Carnwath JW, Klose J, Tiede A, Friedrich L, Baars W, Schwinzer R, Winkler M, Niemann H. Transgenic expression of human heme oxygenase‐1 in pigs confers resistance against xenograft rejection during ex vivo perfusion of porcine kidneys. Xenotransplantation 2011; 18: 355–368.

Inhibition of Autophagic Flux by Salinomycin Results in Anti-Cancer Effect in Hepatocellular Carcinoma Cells

Salinomycin raised hope to be effective in anti-cancer therapies due to its capability to overcome apoptosis-resistance in several types of cancer cells. Recently, its effectiveness against human hepatocellular carcinoma (HCC) cells both in vitro and in vivo was demonstrated. However, the mechanism of action remained unclear. Latest studies implicated interference with the degradation pathway of autophagy. This study aimed to determine the impact of Salinomycin on HCC-autophagy and whether primary human hepatocytes (PHH) likewise are affected. Following exposure of HCC cell lines HepG2 and Huh7 to varying concentrations of Salinomycin (0–10 µM), comprehensive analysis of autophagic activity using western-blotting and flow-cytometry was performed. Drug effects were analyzed in the settings of autophagy stimulation by starvation or PP242-treatment and correlated with cell viability, proliferation, apoptosis induction, mitochondrial mass accumulation and reactive oxygen species (ROS) formation. Impact on apoptosis induction and cell function of PHH was analyzed. Constitutive and stimulated autophagic activities both were effectively suppressed in HCC by Salinomycin. This inhibition was associated with dysfunctional mitochondria accumulation, increased apoptosis and decreased proliferation and cell viability. Effects of Salinomycin were dose and time dependent and could readily be replicated by pharmacological and genetic inhibition of HCC-autophagy alone. Salinomycin exposure to PHH resulted in transient impairment of synthesis function and cell viability without apoptosis induction. In conclusion, our data suggest that Salinomycin suppresses late stages of HCC-autophagy, leading to impaired recycling and accumulation of dysfunctional mitochondria with increased ROS-production all of which are associated with induction of apoptosis.

Impact of Salinomycin on human cholangiocarcinoma: induction of apoptosis and impairment of tumor cell proliferation in vitro

BackgroundCholangiocarcinoma (CC) is a primary liver cancer with increasing incidence worldwide. Despite all efforts made in past years, prognosis remains to be poor. At least in part, this might be explained by a pronounced resistance of CC cells to undergo apoptosis. Thus, new therapeutic strategies are imperatively required. In this study we investigated the effect of Salinomycin, a polyether ionophore antibiotic, on CC cells as an appropriate agent to treat CC. Salinomycin was quite recently identified to induce apoptosis in cancer stem cells and to overcome apoptosis-resistance in several leukemia-cells and other cancer cell lines of different origin.MethodsTo delineate the effects of Salinomycin on CC, we established an in vitro cell culture model using three different human CC cell lines. After treatment apoptosis as well as migration and proliferation behavior was assessed and additional cell cycle analyses were performed by flowcytometry.ResultsBy demonstrating Annexin V and TUNEL positivity of human CC cells, we provide evidence that Salinomycin reveals the capacity to break apoptosis-resistance in CC cells. Furthermore, we are able to demonstrate that the non-apoptotic cell fraction is characterized by sustainable impaired migration and proliferation. Cell cycle analyses revealed G2-phase accumulation of human CC cells after treatment with Salinomycin. Even though apoptosis is induced in two of three cell lines of CC cells, one cell line remained unaffected in regard of apoptosis but revealed as the other CC cells decreased proliferation and migration.ConclusionIn this study, we are able to demonstrate that Salinomycin is an effective agent against previously resistant CC cells and might be a potential candidate for the treatment of CC in the future.

Endothelial-derived thrombospondin-1 promotes macrophage recruitment and apoptotic cell clearance

Rapid apoptotic cell engulfment is crucial for prevention of inflammation and autoimmune diseases and is conducted by special immunocompetent cells like macrophages or immature dendritic cells. We recently demonstrated that endothelial cells (ECs) also participate in apoptotic cell clearance. However, in contrast to conventional phagocytes they respond with an inflammatory phenotype. To further confirm these pro‐inflammatory responses human ECs were exposed to apoptotic murine ECs and changes in thrombospondin‐1 (TSP‐1) expression and in activation of intracellular signalling cascades were determined by real‐time qPCR, immunoblotting and immunocytochemistry. Human primary macrophages or monocytic lymphoma cells (U937) were incubated with conditioned supernatant of human ECs exposed to apoptotic cells and changes in activation, migration and phagocytosis were monitored. Finally, plasma levels of TSP‐1 in patients with anti‐neutrophil cytoplasmic antibody(ANCA)‐associated vasculitis (AAV) were determined by ELISA. We provided evidence that apoptotic cells induce enhanced expression of TSP‐1 in human ECs and that this increase in TSP‐1 is mediated by the mitogen‐activated protein kinases (MAPK) ERK1 and 2 and their upstream regulators MEK and B‐Raf. We also showed that plasma TSP‐1 levels are increased in patients with AAV. Finally, we showed that conditioned supernatant of ECs exposed to apoptotic cells induces pro‐inflammatory responses in monocytes or U937 cells and demonstrated that increased TSP‐1 expression enhances migration and facilitates engulfment of apoptotic cells by monocyte‐derived macrophages or U937 cells. These findings suggest that under pathological conditions with high numbers of uncleared dying cells in the circulation endothelial‐derived elevated TSP‐1 level may serve as an attraction signal for phagocytes promoting enhanced recognition and clearance of apoptotic cells.

Surgery in oesophago-gastric cancer with metastatic disease: Treatment, prognosis and preoperative patient selection

BACKGROUND The role of surgical resection in metastatic oesophago-gastric adenocarcinomas (EGA) is not defined and regularly discussed in interdisciplinary tumour boards. Primary objective of this retrospective study was the outcome of patients after surgery. We additionally evaluated our preoperative prognostic score (PPS) based on tumour grading, clinical response to chemotherapy and presumed R-status. METHODS 123 of 811 EGA patients were evaluated as cM1, either confirmed intraoperatively or by imaging. Response evaluation after chemotherapy was performed by endoscopy, CT-scan and histopathologically. The prospectively documented patient and outcome data were analysed retrospectively. RESULTS 70 patients with adenocarcinoma of the oesophago-gastric junction and 53 patients with gastric cancer were included. The majority had one M1 site (n = 102). 72 received preoperative chemotherapy (CTx) and 51 underwent primary resection. 11 were explored without resection. 49/112 (40%) had multivisceral resections and 63/112 (56%) were completely resected (R0). 26/72 (36%) were clinical responders and 30 patients had a favourable PPS. Median survival was 20.0 months. Survival was significantly prolonged by resection, especially complete resection, and by preoperative CTx (all p = 0.001). Multivisceral resection, type or number of metastases, or primary tumour localization had no impact on survival. In patients undergoing preoperative CTx, clinical response and the PPS influenced survival significantly. In R0 resected patients, preoperative CTx, clinical response and the PPS remained prognostic. CONCLUSION Primary resection without preoperative CTx is not appropriate for metastatic EGA. Subgroups of patients with a favourable PPS with response to CTx may be good candidates for surgical resection in metastatic oesophago-gastric cancer.

Species-specific regulation of fibrinogen synthesis with implications for porcine hepatocyte xenotransplantation.

Patients with liver failure could potentially be bridged with porcine xenogeneic liver cell transplantation. We examined species‐specific differences between primary human and porcine hepatocytes in the regulation of coagulation protein expression and function.

Salinomycin inhibits metastatic colorectal cancer growth and interferes with Wnt/β-catenin signaling in CD133+ human colorectal cancer cells

BackgroundThe polyether antibiotic Salinomycin (Sal) is regarded as an inhibitor of cancer stem cells. Its effectiveness on human colorectal cancer (CRC) cells in vitro has been demonstrated before. The aim of this study was to establish a murine model to investigate the effectiveness of Sal in vivo. Furthermore, we investigated the impact of Sal on Wnt/β-catenin signaling in human CD133+ CRC cells.MethodsThe two murine CRC cell lines MC38 and CT26 were used to analyze the impact of Sal on tumor cell proliferation, viability, migration, cell cycle progression and cell death in vitro. For in vivo studies, CT26 cells were injected into syngeneic BALB/c mice to initiate (i) subcutaneous, (ii) orthotopic, or (iii) metastatic CRC growth. Sal was administered daily, 5-Fluoruracil served as a control. For mechanistic studies, the CD133+and CD133- subpopulations of human CRC cells were separated by flow cytometry and separately exposed to increasing concentrations of Sal. The impact on Wnt/β-catenin signaling was determined by Western blotting and quantitative PCR.ResultsSal markedly impaired tumor cell viability, proliferation and migration, and induced necrotic cell death in vitro. CRC growth in vivo was likewise inhibited upon Sal treatment. Interference with Wnt signaling and reduced expression of the Wnt target genes Fibronectin and Lgr5 indicates a novel molecular mechanism, mediating anti-tumoral effects of Sal in CRC.ConclusionSal effectively impairs CRC growth in vivo. Furthermore, Sal acts as an inhibitor of Wnt/β-catenin signaling. Thus, Salinomycin represents a promising candidate for clinical CRC treatment.

Impact of Anatomic Location on Locally Recurrent Rectal Cancer: Superior Outcome for Intraluminal Tumour Recurrence

BackgroundLocal recurrence of rectal cancer after curative surgery predicts patients’ prognosis. The correlation between the exact anatomic location of tumour recurrence and patients’ survival is still under debate. Thus, this study aimed to investigate the impact of the exact location of recurrent rectal cancer on post-operative morbidity and survival.MethodsThis is a retrospective study including 90 patients with locally recurrent rectal cancer. The location of tumour recurrence was classified into intraluminal and extraluminal recurrence. Univariate and multivariable Cox regression analyses were used to determine the impact on post-operative morbidity and survival.ResultsPatients’ survival with intraluminal recurrence was significantly longer compared to patients with extraluminal recurrence (p = 0.027). Curative resection was associated with prolonged survival in univariate and multivariable analyses (p = 0.0001) and was more often achieved in patients with intraluminal recurrence (p = 0.024). Survival of curative resected patients with intraluminal recurrence was significantly longer compared to curatively resected patients with extraluminal recurrence (p = 0.0001). The rate of post-operative morbidity between intraluminal and extraluminal recurrence was not statistically different (p = 0.59).ConclusionBased on the present investigation, intraluminal recurrence is associated with superior outcome. Post-operative morbidity did not differ significantly between both groups.

Sphincter-Preserving Surgery for Low Rectal Cancer: Do We Overshoot the Mark?

PurposeIntersphincteric resection (ISR) is an alternative to abdominoperineal resection (APR) for a selected subset of patients with low rectal cancer, combining equivalent oncological outcome and sphincter preservation. However, functional results are heterogeneous and often imperfect. The aim of the present investigation was to determine the long-term functional results and quality of life after ISR.MethodsOne hundred forty-three consecutive patients who underwent surgery for low rectal cancer were analysed. Sixty patients received ISR and 83 patients APR, respectively. Kaplan-Meier estimate was used to analyse patients’ survival. The EORTC QLQ-C30, -C29 and the Wexner score were used to determine functional outcome and quality of life.ResultsISR and APR were both associated with comparable morbidity and no mortality. Patients’ disease- and recurrence-free survival after ISR and APR were similar (p = 0.2872 and p = 0.4635). Closure of ileostomy was performed in 73% of all patients after ISR. Long-term outcome showed a rate of incontinence (Wexner score ≥10) in 66% of the patients. Despite this, patients’ quality of life was significantly better after ISR compared to APR in terms of abdominal complaints and psycho-emotional functioning.ConclusionsISR is technically feasible with acceptable postoperative morbidity rates. Functional results following ISR are compromised by incontinence as the most important complication. However, long-term quality of life is superior to APR, which should be considered when selecting patients for ISR.

Recombinant human antithrombin prevents xenogenic activation of hemostasis in a model of pig‐to‐human kidney transplantation

Xenogenic activation of hemostasis (XAH) represents a major hurdle for the transplantation of discordant animal organs into humans as it results in thrombotic microangiopathy (TMA). We have previously shown that recombinant human‐activated protein C (rhAPC) mitigates XAH and TMA in an ex vivo model of pig‐to‐human kidney transplantation. However, the use of rhAPC may not be feasible in a perioperative setting due to possible bleeding complications.