Sensitization of human malignant lymphoid cells to etoposide by fucoidan, a brown seaweed polysaccharide

The search for the substances sensitizing cancer cells to apoptosis induction by chemotherapeutic agents is a task of high importance in the modern strategy of anticancer therapy. The aim of the study was to investigate the apoptogenic and apoptosis-modulating activities of fucoidan (sulfated polysaccharide) isolated from far-eastern brown seaweeds Fucus evanescens in two human malignant lymphoid cell lines, MT-4 and Namalwa. Methods: Apoptosis was assessed morphologically and quantified by flow cytometry analysis of cells stained with propidium iodide. Caspase-3 activation was assayed by flow cytometry with the aid of labeled monoclonal antibodies. Results: The fucoidan at 500 µg/ml was not cytotoxic in MT-4 or Namalwa cells even in the setting of long-term presence in culture medium up to 14 days. Nevertheless, pretreatment of MT-4 but not Namalwa cells with fucoidan followed by the exposure to DNA topoisomerase II inhibitor etoposide led to about two-fold increase in the relative apoptotic index as compared with etoposide alone. Apoptosis enhancement of MT-4 cells by fucoidan was not accompanied by further increase in the number of the cells with active form of caspase-3. Conclusion: The present findings demonstrate for the first time that fucoidan enhances etoposide induced caspase-dependent cell death pathway in MT-4 but not Namalwa cell line. The mechanisms of such enhancement do not seem to be related directly to caspase-3 activation.Одной из важных задач современной стратегии противоопухолевой терапии является поиск веществ, повышающих чувствительность опухолевых клеток к индукции апоптоза под действием химиопрепаратов. Цель: изучение апоптогенной и апоптозмодулирующей активности фукоидана — сульфатированного полисахарида, выделенного из дальневосточной бурой водоросли Fucus evanescens, на двух линиях злокачественных лимфоидных клеток человека MT-4 и Namalwa. Методы: апоптоз выявляли морфологически и количественно проточной цитометрией клеток, окрашенных йодистым пропидием. Активацию каспазы-3 изучали методом проточной цитометрии клеток после реакции с конъюгированными моноклональными антителами. Результаты: фукоидан в дозе 500 мкг/мл не проявлял токсичности в клетках MT-4 или Namalwa даже при длительном присутствии препарата в культурах до 14 сут. Предварительная инкубация клеток MT-4 с фукоиданом в указанной дозе приводила к двукратному повышению относительного апоптотического индекса при действии ингибитора ДНК топоизомеразы II этопозида, причем такого эффекта в клетках Namalwa не отмечено. Повышение апоптотического индекса в клетках MT-4 под влиянием фукоидана при индукции апоптоза этопозидом не сопровождалось приростом процентного содержания клеток с активной формой каспазы-3, в сравнении с таковым при действии одного лишь индуктора апоптоза этопозида. Выводы: впервые продемонстрирована способность фукоидана усиливать этопозидиндуцированный каспазозависимый апоптоз в клетках MT-4. Подобный эффект отсутствовал в клетках Namalwa. Механизм повышения чувствительности злокачественных лимфоидных клеток человека к этопозиду при действии фукоидана, по-видимому, напрямую не связан с активацией каспазы-3

Seasonal variations of the composition and structural characteristics of polysaccharides from the brown alga Costaria costata

was observed in mature alga

Finance, foreign (direct) investment, and the Dutch disease: the case of Colombia

In recent years Colombia has grown relatively rapidly, but it has been a biased growth. The energy sector (the locomotora minero-energetica, to use the rhetorical expression of President Juan Manuel Santos) grew much faster than the rest of the economy, while the manufacturing sector registered a negative rate of growth. These are classic symptoms of the well-known ‘Dutch disease’, but our purpose here is not to establish whether the Dutch disease exists or not, but rather to shed some light on the financial viability of several, simultaneous dynamics: (i) the existence of a traditional Dutch Disease being due to a large increase in mining exports and a significant exchange rate appreciation; (ii) a massive increase in foreign direct investment (FDI), particularly in the mining sector; (iii) a rather passive monetary policy, aimed at increasing purchasing power via exchange rate appreciation; (iv) more recently, a large distribution of dividends from Colombia to the rest of the world and the accumulation of mounting financial liabilities. The paper will show that these dynamics constitute a potential danger for the stability of the Colombian economy. Some policy recommendations are also discussed

Job Creation and Trade in Manufactures: Industry-Level Analysis Across Countries

This paper examines industry-level responses of manufacturing employment in the context of globalization using a large sample of developed, developing, and transition economies. We find that developing countries need atypically high rates of value-added growth (about 10 %) to increase manufacturing employment appreciably (about 4 %). The employment benefits of export orientation are also modest even in “comparative advantage” industries of developing countries. However, diversifying the export basket contributes significantly to employment growth, particularly in the medium- and high-technology industries. Import competition does not undermine employment growth in low-technology industries of developing countries while it displaces jobs in the same industries in Organisation for Economic Co-operation and Development (OECD) and transition economies. For developing countries, import-induced job losses are higher in the more capital-intensive medium-technology industries. Jobs in high-technology industries are less sensitive to imports with positive relationships observed in the OECD. Investment also complements job creation in low-technology industries of developing countries that have yet to industrialize

Dutch disease-cum-financialization booms and external balance cycles in developing countries

We formally investigate the medium-to-long-run dynamics emerging out of a Dutch disease-cum-financialization phenomenon. We take inspiration from the most recent Colombian development pattern. The “pure” Dutch disease first causes deindustrialization by permanently appreciating the economy’s exchange rate in the long run. Financialization, i.e. booming capital inflows taking place in a climate of natural resource-led financial over-optimism, causes medium-run exchange rate volatility and macroeconomic instability. This jeopardizes manufacturing development even further by raising macroeconomic uncertainty. We advise the adoption of capital controls and a developmentalist monetary policy to tackle these two distinct but often intertwined phenomena