The blockage of the high-affinity lysine binding sites of plasminogen by EACA significantly inhibits prourokinase-induced plasminogen activation
ABSTRACT Prourokinase-induced plasminogen activation is complex and involves three distinct reactions: (1) plasminogen activation by the intrinsic activity of prourokinase; (2) prourokinase activation by plasmin; (3) plasminogen activation by urokinase. To further understand some of the mechanisms involved, the effects of epsilon-aminocaproic acid (EACA), a lysine analogue, on these reactions were studied. At a low range of concentrations (10-50 microM), EACA significantly inhibited prourokinase-induced (Glu-/Lys-) plasminogen activation, prourokinase activation by Lys-plasmin, and (Glu-/Lys-) plasminogen activation by urokinase. However, no inhibition of plasminogen activation by Ala158-prourokinase (a plasmin-resistant mutant) occurred. Therefore, the overall inhibition of EACA on prourokinase-induced plasminogen activation was mainly due to inhibition of reactions 2 and 3, by blocking the high-affinity lysine binding interaction between plasmin and prourokinase, as well as between plasminogen and urokinase. These findings were consistent with kinetic studies which suggested that binding of kringle 1-4 of plasmin to the N-terminal region of prourokinase significantly promotes prourokinase activation, and that binding of kringle 1-4 of plasminogen to the C-terminal lysine158 of urokinase significantly promotes plasminogen activation. In conclusion, EACA was found to inhibit, rather than promote, prourokinase-induced plasminogen activation due to its blocking of the high-affinity lysine binding sites on plasmin(ogen).
SourceAvailable from: John Chang-Eun Cha[Show abstract] [Hide abstract]
ABSTRACT: Although fully treatable in the early stages, once cervical cancer has metastasized, patient outcome is poor. The main objective of this study was to examine the effect of dietary supplementation with a nutrient mixture (NM) containing lysine, ascorbic acid, proline, green tea extract and other micronutrients on HeLa cell xenografts in nude female mice. Tumor growth was measured and immunohistochemical staining was evaluated for the following cancer markers: Ki67 (proliferation); matrix metalloproteinase (MMP)-2 and -9 (invasion/metastasis); vascular endothelial growth factor (VEGF) (angiogenesis); terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and B-cell lymphoma 2 (Bcl-2) (apoptosis); cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) (inflammation); and glutathione S-transferase π (GSTπ) (a general cancer marker). Following housing for a week, 5/6-week-old female athymic nude mice (n=12) were inoculated subcutaneously with 3×10(6) HeLa cells in 0.2 ml phosphate-buffered saline and 0.1 ml Matrigel™ and randomly divided into two groups; control group mice were fed regular mouse chow and NM group mice the regular diet supplemented with 0.5% NM (w/w). After four weeks, the mice were sacrificed and their tumors were excised and processed for histology. The NM strongly inhibited the growth of HeLa xenografts in nude mice. The mean tumor weight was reduced to 59% (P=0.001) in the mice fed the NM compared with the tumor weight in the controlled diet mice. Ki67, MMP-2 and -9, VEGF, TUNEL, Bcl-2, COX-2, iNOS and GSTπ all showed a lower intensity and frequency of staining in the NM group compared with that in the control group. In conclusion, NM supplementation strongly inhibited tumor growth and cancer markers in female nude mice injected with HeLa xenografts.Experimental and therapeutic medicine 02/2015; 9(2):294-302. DOI:10.3892/etm.2014.2127 · 0.94 Impact Factor
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ABSTRACT: Consumption of a plant-based diet has been associated with prevention of the development and progression of cancer. We have developed strategies to inhibit cancer by increasing the stability and integrity of connective tissue as the common mechanisms used by all types of cancer cells for their development and spread. This can be achieved naturally through the synergistic effects of selected nutrients, such as lysine, proline, ascorbic acid and green tea extract (NM). This micronutrient mixture has exhibited anticancer activity in vivo and in vitro in a large variety of cancer cell lines by simultaneously affecting several key mechanisms invoved in cancer. Among them it was effective in inhibition of cancer cell growth, MMP secretion, invasion and metastasis. It inhibited cellular MMP secretion and had anti-angiogenic and pro-apoptotic effects. We investigated the effect of NM on bladder cancer, which is associated with a high rate of recurrence, even when treated in situ, and poor prognosis once the cancer has metastasized. The effect of NM on human bladder cancer cells T-24 was studied in vitro by measuring: cell proliferation, MMP expression, Matrigel invasion, cell migration, apoptosis, and inflammatory protein expression Cox-2 and iNOS. Human bladder cancer cells T-24 (ATCC) were grown in McCoy medium supplemented with 10% FBS, penicillin (100 U/ml) and streptomycin (100 mg/ml) in 24-well tissue culture plates. At near confluence, the cells were treated with NM dissolved in media and tested at 0, 10, 100, 500, and 1000 μg/ml in triplicate at each dose. Cells were also treated with PMA 200 ng/ml to study enhanced expression of MMP-9. Cell proliferation was evaluated by MTT assay, MMP expression by gelatinase zymography, migration by scratch test, invasion through Matrigel, morphology by H&E staining, apoptosis by live-green caspase, and Cox-2 and iNOS by Western blot. NM showed no significant antiproliferative effect on human bladder cancer cell growth but induced apoptosis in a dose-dependent manner. NM inhibited the T-24 cell expression of MMP-2 and –9 in a The exclusive license for this PDF is limited to personal printing only. No part of this digital document may be reproduced, stored in a retrieval system or transmitted commercially in any form or by any means. The publisher has taken reasonable care in the preparation of this digital document, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained herein. This digital document is sold with the clear understanding that the publisher is not engaged in rendering legal, medical or any other professional services.