THE INFLUENCE OF DOXORUBICIN ON NUCLEAR AND CYTOPLASMIC POOL OF F-ACTIN IN THE A549 CELL LINE

 The cytoskeleton as an intracellular system plays an important role in the proper functioning of the cell. F-actin is one of the components, which built this structure. Microfilaments are involved in cell shape maintenance, polarity and cell motility. The aim of the present study was to determine the effect of doxorubicin on the actin reorganization and type of induced cell death in A549 cell line. In order to examine F-actin, the material was evaluated by the confocal and classical fluorescence microscope. Furthermore, changes in morphology and ultrastructure were analyzed by a light and transmission electron microscopy. The obtained data showed that doxorubicin causes a dosedependent decrease in A549 cell viability. Moreover, the treatment with doxorubicin resulted in the reorganization of F-actin as well as the induction of apoptosis and mitotic catastrophe in the non-small lung cancer cells. In addition, the existence of actin in the nucleus was confirmed.Cytoszkielet stanowi międzykomórkowy system, odgrywający istotną rolę w prawidłowym funkcjonowaniu każdej komórki. Jednym z jego komponentów jest F-aktyna, zaangażowana w zmiany kształtu, polarność, a także ruch komórek. Celem przedstawionej pracy było określenie wpływu doksorubicyny na reorganizację cytoszkieletu aktynowego oraz rodzaj indukowanej śmierci w komórkach linii A549. Wyniki badań oceniano przy użyciu klasycznego oraz konfokalnego mikroskopu fluorescencyjnego, a także z wykorzystaniem mikroskopii świetlnej oraz transmisyjnej mikroskopii elektronowej. W toku badań wykazano dawkozależną wrażliwość komórek linii A549 na doksorubicynę. Wraz ze wzrostem cytostatyku, wzrastał odsetek komórek martwych. Ponadto stwierdzono, że doksorubicyna powoduje zmiany w reorganizacji F-aktyny w komórkach niedrobnokomórkowego raka płuca, a także może indukować apoptozę oraz katastrofę mitotyczną. Dodatkowo potwierdzono występowanie aktyny na terenie jądra komórkowego

Chemical proprieties of the iron-quinone complex in mutated reaction centers of Rb. sphaeroides

We investigated type II bacterial photosynthetic reaction centers, which contain a quinone - iron complex (Q_A-Fe-Q_B) on their acceptor side. Under physiological conditions it was observed mainly in a reduced high spin state but its low spin ferrous states were also observed. Therefore, it was suggested that it might regulate the dynamical properties of the iron–quinone complex and the protonation and deprotonation events in its neighbourhood. In order to get insight into the molecular mechanism of the NHFe low spin state formation, we preformed Mössbauer studies of a wild type of Rb. sphaeroides and its two mutated forms. Our Mössbauer measurements show that the hydrophobicity of the Q_A binding site can be crucial for stabilization of the high spin ferrous state of NHFe

Possibilities in the application of solid lipid nanoparticles in combination with 5-fluorouracil to overcome the drugresistance of non-small cell lung cancer cell line A549

Introduction: Multidrug resistance of non-small cell lung cancer cells is associated with a high percentageof therapeutic failures. The aim of this study was to assess the ability of solid lipid nanoparticles as atransporter of the conventionally used cytostatic (5-fluorouracil) to overcome the resistance of A549 cells.Material and methods: MTT assay was used to assess the differences in viability of cells treated with5-fluorouracil alone or in combination with different types of solid lipid nanoparticles. Type of cell deathand distribution of cell cycle phases were evaluated using flow cytometry.Results: The use of nanoparticles as a 5-fluorouracil transporter reduced the viability of A549 cells to agreater extent than the cytostatic alone. This was mainly due to the increase in apoptosis, but also necrosisand cell cycle arrest.Conclusion: Our results indicate the great potential of nanotechnology in the treatment of non-small celllung cancer. By using nanoparticles, it is possible to sensitise tumour cells to cytostatics to which theyare normally resistant. In addition, literature data confirm the safety of solid lipid nanoparticle application

The influence of house dust extract on normal lung cell Mrc5 and non-small lung carcinoma A549

Introduction. Desensitisation is a therapeutic method of allergic disease treatment, but its impact on the cellular level remains to be elucidated. The purpose of this study was to identify the influence of house dust extract on two cell lines types: non-small lung cancer A549 and non-cancerous lung fibroblast Mrc5. Furthermore, we analysed cell viability, type of cell death, and reorganisation of mainly cytoskeletal proteins such as vimentin, F-actin, and b-tubulin. Material and methods. To determine the cell viability, the MTT test was used. The type of cell death was analysed using double staining of annexin V and iodide propidium. The reorganisation of cytoskeletal proteins was evaluated by fluorescent staining and microscopy observation. Results. Our data presented non-statistical differences in a population of live, apoptotic, and necrotic cells. We did not observe significant abnormalities in cytoskeletal reorganisation. Moreover, Mrc5 cell line exhibited a lower sensitivity for house dust extract in comparison to A549 cell line. Conclusions. Our study suggests that desensitisation has no significant influence on survival and cytoskeleton in both cell lines, which correlate with potential use of this method in cancer patients. Obviously, the choice of these kinds of treatment should be used carefully in consultation with a specialist. Additionally, to our knowledge, it was the first presentation of the influence of house dust extract on cells in the context of the main cytoskeletal reorganisations.

Skuteczne leczenie niewydolności serca opornej na diuretyki za pomocą ultrafiltracji otrzewnowej

We present a case of successful peritoneal ultrafiltration (pUF) treatment in a 60 year-old patient diagnosed with diuretic-resistantcongestive heart failure fulfilling the criteria for type 2 cardio-renal syndrome. Six months of pUF treatment with onedaily dialysis exchange with icodextrin as an osmotic agent resulted in better functional status (from IV to II/III NYHA class),quality of life and improvement of haemodynamic parameters measured by impedance cardiography. During the follow-up(six months), pUF was well tolerated by the patient and he did not require hospitalisation for decompensated heart failure

Synergistic effect of oxymatrine and 5-fluorouracil on the migratory potential in A549 non-small cell lung cancer cells

Introduction: An interesting research direction is the development of new therapies to reduce metastasis, especially in highly invasive cancer such as lung cancer. One of the commonly used anti-cancer drugs is 5-fluorouracil. Oxymatrine is a natural alkaloid with a wide range of effects. Combined with a cytostatic, it may enhance its action and protect normal cells. Therefore, the study aimed to analyse the effect of oxymatrine and 5-fluorouracil on non-small lung cancer cell line A549. Material and methods: The study was based on the assessment of the interaction between drugs, cell death, cell cycle phase distribution, fluorescent labelling of F-actin and b-catenin, as well as wound healing and transwell migration assay. Results: The combined treatment with oxymatrine and the cytostatic in a 1:1 ratio resulted in synergism. Incubation of cells with both substances induced changes in the life processes of A549 cells. In turn, the reorganization of F-actin and b-catenin contributed to the limitation of lung cancer cell migration compared to individual treatment with compounds. Conclusions: This study demonstrated that the combination of oxymatrine and 5-fluorouracil in the 1:1 ratio may limit the migratory potential of A549 cells. In summary, oxymatrine can support the anti-cancer effect of 5-fluorouracil, but its potential application should be examined in further studies

Effect of combined action of doxorubicin and calcifediol on MCF-7 breast cancer cells

Introduction: Breast cancer is one of the most common cancers in women. Current recommendations for combination therapy in patients with breast cancer are still being developed and new therapies with greater success are sought. A relatively new approach is the administration of cytostatics in combination with vitamins. Hence, the study aimed to clarify whether the combination of calcifediol [25(OH)D3] with doxorubicin affects the response of the MCF-7 breast cancer cell line to the cytostatic. Material and methods: In the MCF-7 cell line, the authors assessed cytotoxicity using the MTT assay, analysed the cell cycle and cell death mechanism using flow cytometry, and examined the structure of the cytoskeleton and cell morphology. Results: The results showed that doxorubicin in combination with calcifediol in a 1:1 ratio showed a synergistic effect resulting in a dose-dependent decrease in cell survival. Further studies have shown that this is due to the pro-apoptotic and necrotic effects of the combination of these compounds. There were also changes in the organization of the cytoskeleton and cell morphology. In addition, features of entosis were noted in MCF-7 cells. Conclusion: The synergistic effect of doxorubicin and calcifediol significantly reduced the viability of MCF-7 breast cancer cells. Inducing the desired effect by lowering the cytostatic dose is of great clinical importance, taking into account the cardiotoxicity of doxorubicin. Another very interesting aspect is the entosis process induced in the present research, which may have a dual nature

Involvement of the essential yeast DNA polymerases in induced gene conversion

In the yeast Saccharomyces cerevisiae three different DNA polymerases α, δ and ε are involved in DNA replication. DNA polymerase α is responsible for initiation of DNA synthesis and polymerases δ and ε are required for elongation of DNA strand during replication. DNA polymerases δ and ε are also involved in DNA repair. In this work we studied the role of these three DNA polymerases in the process of recombinational synthesis. Using thermo-sensitive heteroallelic mutants in genes encoding DNA polymerases we studied their role in the process of induced gene conversion. Mutant strains were treated with mutagens, incubated under permissive or restrictive conditions and the numbers of convertants obtained were compared. A very high difference in the number of convertants between restrictive and permissive conditions was observed for polymerases α and δ, which suggests that these two polymerases play an important role in DNA synthesis during mitotic gene conversion. Marginal dependence of gene conversion on the activity of polymerase ε indicates that this DNA polymerase may be involved in this process but rather as an auxiliary enzyme