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In JoVE (1)
Other Publications (20)
- The Annals of Thoracic Surgery
- ASHA
- Journal of Medicine
- ASHA
- Archives of Biochemistry and Biophysics
- Bulletin of the American College of Surgeons
- Bulletin of the American College of Surgeons
- The American Journal of Pathology
- Journal of Pharmaceutical Sciences
- Optometry (St. Louis, Mo.)
- Clinical Cancer Research : an Official Journal of the American Association for Cancer Research
- Optometry (St. Louis, Mo.)
- Optometry (St. Louis, Mo.)
- Diagnostic Molecular Pathology : the American Journal of Surgical Pathology, Part B
- Annals of Surgical Oncology
- Optometry (St. Louis, Mo.)
- Optometry (St. Louis, Mo.)
- Optometry (St. Louis, Mo.)
- The Journal of Surgical Research
- Bioorganic & Medicinal Chemistry Letters
Articles by Markus Günl in JoVE
JoVE General
OLIgo Mass Profiling (OLIMP) of Extracellular Polysaccharides
1Energy Biosciences Institute, University of California, Berkeley, 2Department of Plant and Microbial Biology, University of California, Berkeley
A rapid way is described to gain insights into the structure of polysaccharides in an extracellular matrix. The method takes advantage of the specificity of glycosylhydrolases and the sensitivity of mass spectrometry allowing minute amounts of materials to be analyzed. This technique is adaptable to be used directly on tissue itself.
Other articles by Markus Günl on PubMed
Potentiation of Thrombolytic Therapy by Enzyme Combinations and with Aspirin or Pentoxifylline
Radioactively labeled human fibrin clots were placed into veins of Macaca arctoides monkeys. Thrombolysis was recorded by the disappearance of radioactivity and by angiography. Streptokinase (SK) and urokinase (UK) induced thrombolysis was potentiated by low dose aspirin (ASA) and pentoxifylline (PE). Studies on the mechanisms of action revealed that PE inhibits platelet aggregation, releases tissue plasminogen activator (t-PA) from the endothelium, increases red cell deformability and inhibits white cell adhesion. Thrombolysis by pro-urokinase (pro-UK) was potentiated by low dose SK probably because of streptokinase-plasmin activation of pro-UK to UK. Platelet aggregation inhibitory effects, disaggregation of platelet aggregate inducing effects, and the t-PA releasing activity of PE was demonstrated in patients with obstructive cardiovascular disease. Pharmacodynamic studies suggested that PE metabolites one and five are most effective from this point of view. These metabolites are currently studied in combination with thrombolytic enzymes.
Cancer Cells Release a Covalent Complex Containing Disulfide-linked Domains from Urinary Plasminogen Activator, Neural Cell Adhesion Molecule, and Haptoglobin Alpha and Beta Chains
We have previously reported on the secretion of a family of high Mr plasminogen activators (PAs) by a human lung cancer cell line [Harvey et al. (1991) Biochim. Biophys. Acta 1078, 360-368]. We have now extended these studies to several human cancer cell lines and a human embryonic lung cell line. In the present study with HPL-SK-1 lung cancer, A431 epidermoid cancer, ovarian carcinoma, and embryonic lung cell lines, we show that the 900- and the 660-kDa PAs are disulfide-bonded multiprotein oligomeric complexes. They are functionally and immunologically related to human urinary PA (uPA). Their size and PA activity are not destroyed by strong denaturants such as 8 M urea or 2% sodium dodecyl sulfate (SDS), suggesting that the uPA moiety is covalently associated with the rest of the molecule. It is only under strong denaturing conditions with 1.4 M beta-mercaptoethanol and 2% SDS that the uPA moiety could be released as a 21- to 23-kDa fragment along with two major polypeptide chains of 70 and 40 kDa, respectively. The presence of the uPA active center in the reduced PA660 was demonstrated by [3H]diisopropylphosphorofluoridate labeling and by Western blot using a monoclonal antibody to uPA B chain. N-terminal amino acid sequencing of the 70- and 40-kDa polypeptides, respectively, showed homology to the neural cell adhesion molecule and the beta chain of haptoglobin. A minor fragment of 18 kDa obtained under strong reduction conditions was also sequenced and shown to share homology with the alpha chain of haptoglobin. Western blot analysis of the reduced PAs with monoclonal antibody to the neural cell adhesion molecule and rabbit anti-haptoglobin confirmed the homologies obtained by the sequence data. Further, immobilized monoclonal antibodies to the neural cell adhesion molecule, uPA B chain, and rabbit anti-haptoglobin bound the multiprotein complexes with uPA activity, from A431, ovarian cancer, and embryonic lung cell lines. The bound material, after dissociation, exhibited PA activity that was inhibited by monoclonal antibody to the uPA B chain. These data suggest that in tumor and embryonal cell lines, in addition to proper folding and assembly of proteins by intramolecular disulfide bond formation in the endomembrane compartment, intermolecular disulfide bonds could also occur, producing multiprotein oligomers as in the present case. Formation of such oligomers may have a selective advantage for such cells in the focalization of proteolytic activity through the interaction of the neural cell adhesion molecule domain with the extracellular matrix and in immunosuppression of lymphocytes by the haptoglobin portion of the complex.
Demonstration of Urokinase Expression in Cancer Cells of Colon Adenocarcinomas by Immunohistochemistry and in Situ Hybridization
The question whether urokinase is expressed in human colon cancer by the cancer cells themselves or by surrounding stromal elements such as fibroblasts, macrophages, and leukocytes, which transfer the activator to the receptors of the cancer cells, has been a controversial one. In the present study 12 cases of colorectal cancer were investigated by immunohistochemical methods using three monoclonal antibodies of different specificity against urokinase. Cytoplasmic staining of strongly varying intensity was observed in all cases, with the antigen expressed most strongly in the apical and the basal regions of the cancer cells. In some cases, staining was also found in stromal elements surrounding the cancer glands. That the activator was indeed the product of the cancer cells was demonstrated by in situ hybridization using a uPA-cDNA probe, which detected the presence of uPA-mRNA in both the basal and the apical regions of the cancer cells. A monoclonal antibody against the receptor for uPA showed similar localization. These findings indicate that the activator is expressed by the cancer cells and is not recruited by them from stromal elements.
Enhanced Human Nail Drug Delivery: Nail Inner Drug Content Assayed by New Unique Method
The purpose of this study was to develop an assay method of the human inner nail plate and to compare nail drug penetration by a penetrating enhancing formulation (the test carrier formulation). The test carrier and saline formulations were tested using radiolabeled urea, ketoconazole, and salicylic acid. After twice dosing daily for 7 days on human nail plates, the under inner section of the nail plate was assayed for absorbed drug content using a unique drilling/removal system. Results show that the weight-normalized radioactivity contents of three chemicals in the inner intermediate nail plate center in the carrier formulation were two fold higher than those from saline (p < 0.05). Total radioactivity recovery of dosed [(14)C]-salicylic acid was 89 +/- 2% in the carrier formulation and 88 +/- 5% in saline. In saline formulation, salicylic acid showed greater binding to the outer nail, making it less bioavailable for the inner nail area. This didn't occur with carrier formulation. In conclusion, topical treatment of nail diseases such as onychomycosis is not yet sufficiently effective, likely because of minimal drug penetration into the inner nail plate where the disease perpetuates. The assay system has the unique characteristic of being able to assay the inner part of the nail where the disease resides.
Evaluation of Urinary Plasminogen Activator, Its Receptor, Matrix Metalloproteinase-9, and Von Willebrand Factor in Pancreatic Cancer
Pancreatic cancer remains a devastating problem with the majority of patients succumbing to death from this disease. A hallmark of pancreatic cancer is the loss of basement membrane that may be attributed to the action of urinary plasminogen activator (uPA) and matrix metalloproteinase-9 (MMP-9). These enzymes are also implicated in angiogenesis. uPA and microvessel density have been shown to be good prognostic indicators for breast and colon cancer. MMP-9 and microvessel density have not been investigated in pancreatic cancer. We have therefore investigated by immunohistochemistry: (a) frequency of uPA expression and its receptor uPAR and the site of synthesis of uPA by in situ hybridization (ISH); (b) MMP-9 and its coexpression with uPA; (c) microvessel density as determined by von Willebrand factor staining and its relationship to uPA and MMP-9 expression; and (d) correlation of these parameters with survival.
Overexpression of Urinary Plasminogen Activator (uPA) Protein and MRNA in Thyroid Carcinogenesis
Urinary plasminogen activator (uPA), a protease, is one of the critical components of tumor invasion and metastasis. Its expression in thyroid carcinoma and potential role in thyroid tumorigenesis are unknown. The objective of this study was to determine whether uPA is differentially expressed in benign and malignant thyroid tumors.
Plasminogen Activator System Localization in 60 Cases of Ductal Carcinoma in Situ
The lack of prognostic factors in ductal carcinoma in situ (DCIS) that reliably identifies biologically aggressive tumors adversely affects optimal management. The urokinase-type plasminogen activator (uPA) system, comprised of its receptor, uPAR, and its inhibitor (PAI-1), are critical elements for tumor invasion and their expression in invasive breast cancer can predict clinical outcome. Expression of the uPA system in DCIS may be relevant in defining histological subsets of DCIS with invasive potential.
Co-expression of Urokinase with Haptoglobin in Human Carcinomas
We have shown that colon and breast cancer contains large amounts of urokinase (uPA), and that these cells are the actual sites of its synthesis. We isolated a large complex molecule consisting of the beta-chain of uPA, both chains of haptoglobin (Hp), and part or all of an NCAM-like molecule. The question arose whether it would be possible to show the presence of Hp in the same cells where uPA was found.
Identification of Lysine Acetyltransferase P300 Substrates Using 4-pentynoyl-coenzyme A and Bioorthogonal Proteomics
Proteomic studies have identified a plethora of lysine acetylated proteins in eukaryotes and bacteria. Determining the individual lysine acetyltransferases responsible for each protein acetylation mark is crucial for elucidating the underlying regulatory mechanisms, but has been challenging due to limited biochemical methods. Here, we describe the application of a bioorthogonal chemical proteomics method to profile and identify substrates of individual lysine acetyltransferases. Addition of 4-pentynoyl-coenzyme A, an alkynyl chemical reporter for protein acetylation, to cell extracts, together with purified lysine acetyltransferase p300, enabled the fluorescent profiling and identification of protein substrates via Cu(I)-catalyzed alkyne-azide cycloaddition. We identified several known protein substrates of the acetyltransferase p300 as well as the lysine residues that were modified. Interestingly, several new candidate p300 substrates and their sites of acetylation were also discovered using this approach. Our results demonstrate that bioorthogonal chemical proteomics allows the rapid substrate identification of individual protein acetyltransferases in vitro.
