Markus W. Buechler

Bio: Markus W. Buechler is an academic researcher from Heidelberg University. The author has contributed to research in topics: Pancreatic cancer & Clinical trial. The author has an hindex of 16, co-authored 42 publications receiving 1238 citations. Previous affiliations of Markus W. Buechler include University Hospital Heidelberg.

Glyoxalase-1 prevents mitochondrial protein modification and enhances lifespan in Caenorhabditis elegans.

Abstract: Studies of mutations affecting lifespan in Caenorhabditis elegans show that mitochondrial generation of reactive oxygen species (ROS) plays a major causative role in organismal aging. Here, we describe a novel mechanism for regulating mitochondrial ROS production and lifespan in C. elegans: progressive mitochondrial protein modification by the glycolysis-derived dicarbonyl metabolite methylglyoxal (MG). We demonstrate that the activity of glyoxalase-1, an enzyme detoxifying MG, is markedly reduced with age despite unchanged levels of glyoxalase-1 mRNA. The decrease in enzymatic activity promotes accumulation of MG-derived adducts and oxidative stress markers, which cause further inhibition of glyoxalase-1 expression. Over-expression of the C. elegans glyoxalase-1 orthologue CeGly decreases MG modifications of mitochondrial proteins and mitochondrial ROS production, and prolongs C. elegans lifespan. In contrast, knock-down of CeGly increases MG modifications of mitochondrial proteins and mitochondrial ROS production, and decreases C. elegans lifespan.

Application of laser capture microdissection combined with two-dimensional electrophoresis for the discovery of differentially regulated proteins in pancreatic ductal adenocarcinoma.

Abstract: Pancreatic ductal adenocarcinoma (PDAC) is the most lethal of all the common malignancies and markers for early detection or targets for treatment of this disease are urgently required. The disease is characterised by a strong stromal response, with cancer cells usually representing a relatively small proportion of the cells in the tumor mass. We therefore performed laser capture microdissection (LCM) to enrich for both normal and malignant pancreatic ductal epithelial cells. Proteins extracted from these cells were then separated by two-dimensional gel electrophoresis (2-DE). The limited amounts of protein in the LCM procured samples necessitated the detection of 2-DE resolved proteins by silver staining. Consequently, loading equivalent amounts of protein onto gels was essential. However, we found that conventional means of measuring total protein in the samples were not sufficiently accurate. We therefore adopted a strategy in which the samples were first separated by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis, stained with silver stain and subjected to densitometry. Evaluation of the staining intensity was then used to normalise the samples. We found that the protein profiles from undissected normal pancreas and LCM-acquired non-malignant ductal epithelial cells from the same tissue block were different, underpinning the value of LCM in our analysis. The comparisons of protein profiles from nonmalignant and malignant ductal epithelial cells revealed nine protein spots that were consistently differentially regulated. Five of these proteins showed increased expression in tumor cells while four showed diminished expression in these cells. One of the proteins displaying enhanced expression in tumor cells was identified as the calcium-binding protein, S100A6. To determine the incidence of S100A6 overexpression in pancreatic cancer, we carried out immunohistochemical analysis on sections from a pancreas cancer tissue array containing 174 duplicate normal and malignant pancreatic tissue samples, from 46 pancreas cancer patients. Normal pancreatic ductal epithelia were either devoid of detectable S100A6 or showed weak expression only. Moderately or poorly differentiated tumors, by contrast, showed a higher incidence and a higher level of S100A6 expression. These observations indicate that the combination of LCM with 2-DE provides an effective strategy to discover proteins that are differentially expressed in PDAC.

Primary and locally recurrent retroperitoneal soft-tissue sarcoma: Local control and survival

Abstract: Aim To evaluate local control for long-term prognosis in retroperitoneal soft-tissue sarcoma (primary tumors (PT) and local recurrence (LR)). Methods A total of 110 patients underwent surgery between 1988 and 2002. Prospectively gathered clinicopathological data were analyzed. Kaplan–Meier estimations and Cox regression analyses were performed. Results Resectability was 90%, being comparable for PT (n = 71) and LR (n = 39). Morbidity, mortality, blood loss, and operation time did not differ for PT or LR (24% vs. 31%, p = 0.41; 7.0% vs. 5.1%, p = 1.0; 1000 ml vs. 1500 ml, p = 0.17; 240 min vs. 255 min, p = 0.13). Hospitalization was comparable in both groups (median, 12 days (PT) and 13 days (LR)). Follow-up was 89 months (median, IQR 37–112 months). Local 3- and 5-year control rates after complete resection of PT were 66% and 59% (19% and 9% for LR, p Conclusions Comparable resectability rates and perioperative outcome were observed for surgery of PT and LR. Consequent reoperation leads to respectable long-term survival rates after resection of LR. The prognosis in retroperitoneal sarcomas varies significantly according to resectability, grade and blood loss.

Monitoring of NFAT-regulated gene expression in the peripheral blood of allograft recipients: a novel perspective toward individually optimized drug doses of cyclosporine A.

Abstract: Background. With the introduction of cyclosporine A (CsA), long-term allograft function has significantly improved. Problems related to limited therapeutic margins and CsA toxicity remain unsolved. Until now there have been no reliable, practical markers to measure the biologic activity of CsA in vivo. Methods. Expression of NFAT (nuclear factor of activated T cells)-regulated genes (interleukin 2, interferon-, and granulocyte-macrophage colony-stimulating factor) in phorbol myristate acetate/ionomycinstimulated peripheral blood from healthy volunteers (n34) and from stable renal (n25), cardiac (n26), and liver (n14) transplant recipients receiving CsA therapy was measured by quantitative real-time reverse transcriptase-polymerase chain reaction before and 2 hr after drug intake. Gene expression and CsA plasma levels were correlated. Results. Two hours after oral CsA ingestion, the mean suppression of induced interleukin 2, interferon-, and granulocyte-macrophage colony-stimulating factor gene expression was 85%. The individual decline of NFAT-regulated gene expression and the total drug exposure at this time point were closely related. Six hours after oral CsA uptake, gene expression levels reached predose values and subsequently increased further in some patients (rebound effect). Conclusion. Quantitative measurement of the inhibition of NFAT-regulated gene expression 2 hr after CsA intake represents a novel approach to assess the biologic effectiveness of CsA therapy and has the potential to enable individualized immunosuppressive regimens. Cyclosporine A (CsA) has improved patient and organ graft survival, but the issue of benefit and toxicity remains unsolved (1–3). CsA treatment is still monitored according to CsA predose

Tumour-associated macrophages as treatment targets in oncology

Abstract: Macrophages are crucial drivers of tumour-promoting inflammation. Tumour-associated macrophages (TAMs) contribute to tumour progression at different levels: by promoting genetic instability, nurturing cancer stem cells, supporting metastasis, and taming protective adaptive immunity. TAMs can exert a dual, yin-yang influence on the effectiveness of cytoreductive therapies (chemotherapy and radiotherapy), either antagonizing the antitumour activity of these treatments by orchestrating a tumour-promoting, tissue-repair response or, instead, enhancing the overall antineoplastic effect. TAMs express molecular triggers of checkpoint proteins that regulate T-cell activation, and are targets of certain checkpoint-blockade immunotherapies. Other macrophage-centred approaches to anticancer therapy are under investigation, and include: inhibition of macrophage recruitment to, and/or survival in, tumours; functional re-education of TAMs to an antitumour, 'M1-like' mode; and tumour-targeting monoclonal antibodies that elicit macrophage-mediated extracellular killing, or phagocytosis and intracellular destruction of cancer cells. The evidence supporting these strategies is reviewed herein. We surmise that TAMs can provide tools to tailor the use of cytoreductive therapies and immunotherapy in a personalized medicine approach, and that TAM-focused therapeutic strategies have the potential to complement and synergize with both chemotherapy and immunotherapy.

Roles of the immune system in cancer: from tumor initiation to metastatic progression.

Abstract: The presence of inflammatory immune cells in human tumors raises a fundamental question in oncology: How do cancer cells avoid the destruction by immune attack? In principle, tumor development can be controlled by cytotoxic innate and adaptive immune cells; however, as the tumor develops from neoplastic tissue to clinically detectable tumors, cancer cells evolve different mechanisms that mimic peripheral immune tolerance in order to avoid tumoricidal attack. Here, we provide an update of recent accomplishments, unifying concepts, and future challenges to study tumor-associated immune cells, with an emphasis on metastatic carcinomas.

Liver macrophages in tissue homeostasis and disease

Abstract: Macrophages represent a key cellular component of the liver, and are essential for maintaining tissue homeostasis and ensuring rapid responses to hepatic injury. Our understanding of liver macrophages has been revolutionized by the delineation of heterogeneous subsets of these cells. Kupffer cells are a self-sustaining, liver-resident population of macrophages and can be distinguished from the monocyte-derived macrophages that rapidly accumulate in the injured liver. Specific environmental signals further determine the polarization and function of hepatic macrophages. These cells promote the restoration of tissue integrity following liver injury or infection, but they can also contribute to the progression of liver diseases, including hepatitis, fibrosis and cancer. In this Review, we highlight novel findings regarding the origin, classification and function of hepatic macrophages, and we discuss their divergent roles in the healthy and diseased liver.