BACKGROUND: We investigated the targeting of microtubules (MT) and F-actin cytoskeleton (AC) of the human pathogenic yeast Cryptococcus neoformans with agents for cancer therapy, in order to examine whether this yeast cytoskeleton could become a new antifungal target for the inhibition of cell division. METHODS: Cells treated with 10 cytoskeleton inhibitors in yeast extract peptone dextrose medium were investigated by phase-contrast and fluorescence microscopy, and growth inhibition was estimated by cell counts using a Bürker chamber and measuring absorbance for 6 days. RESULTS: Docetaxel, paclitaxel, vinblastine sulfate salt, cytochalasin D and chlorpropham [isopropyl N-(3-chlorophenyl) carbamate] did not inhibit proliferation. The MT inhibitors methyl benzimidazole-2-ylcarbamate (BCM), nocodazole, thiabendazole (TBZ) and vincristine (VINC) disrupted MT and inhibited mitoses, but anucleated buds emerged on cells that increased in size, vacuolated and seemed to die after 2 days. The response of the cells to the presence of the actin inhibitor latrunculin A (LA) included the disappearance of actin patches, actin cables and actin rings; this arrested budding and cell division. However, in 3-4 days, resistant budding cells appeared in all 5 inhibitors. Disruption of the MT and AC and inhibition of cell division and budding persisted only when the MT and AC inhibitors were combined, i.e. VINC + LA, BCM + LA or TBZ + LA. CONCLUSION: The MT and AC of C. neoformans are new antifungal targets for the persistent inhibition of cell division by combined F-actin and MT inhibitors.
- MeSH
- aktiny antagonisté a inhibitory MeSH
- antifungální látky farmakologie MeSH
- antitumorózní látky farmakologie MeSH
- bicyklické sloučeniny heterocyklické farmakologie MeSH
- buněčné dělení účinky léků MeSH
- Cryptococcus neoformans účinky léků MeSH
- fluorescenční mikroskopie MeSH
- lidé MeSH
- mikrofilamenta účinky léků MeSH
- mikrotubuly účinky léků MeSH
- racionální návrh léčiv MeSH
- thiazolidiny farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: This basic research aimed to investigate the effects of the actin inhibitor latrunculin A (LA) on the human pathogen Cryptococcus neoformans, by freeze-substitution (FS) and electron microscopy (EM), to determine whether the actin cytoskeleton can become a new antifungal target for inhibition of cell division. METHODS: Cells treated with LA for 20 h in yeast-extract peptone dextrose medium were investigated by phase-contrast and fluorescent microscopy, FS and transmission EM, counted in a Bürker chamber and the absorbance was then measured. RESULTS: The disappearance of actin patches, actin cables and actin rings demonstrated the response of the cells of C. neoformans to the presence of the actin inhibitor LA. The removal of actin cables and patches arrested proliferation and led to the production of cells that had ultrastructural disorder, irregular morphology of the mitochondria and thick aberrant cell walls. Budding cells lysed in the buds and septa. CONCLUSION: LA exerts fungistatic, fungicidal and fungilytic effects on the human pathogenic yeast C. neoformans.
- MeSH
- aktiny antagonisté a inhibitory MeSH
- antifungální látky farmakologie MeSH
- bicyklické sloučeniny heterocyklické farmakologie MeSH
- buněčná stěna účinky léků metabolismus MeSH
- buněčné dělení účinky léků MeSH
- Cryptococcus neoformans účinky léků metabolismus MeSH
- elektronová mikroskopie metody MeSH
- fluorescenční mikroskopie metody MeSH
- kryptokokóza farmakoterapie metabolismus mikrobiologie MeSH
- lidé MeSH
- mikrofilamenta účinky léků metabolismus MeSH
- proliferace buněk účinky léků MeSH
- thiazolidiny farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Resistance of cancer cells to chemotherapeutic agents is a major cause of treatment failure in patients with cancer. The drug resistance of tumor cells can be significantly modified by specific features of tumor microenvironment, such as oxygen depletion (hypoxia), glucose/energy deprivation and acidosis. METHODS: The effects of acidic tumor-like microenvironment on cytotoxicity of antabuse (disulfiram, DSF)/Cu(2+) complexes to MCF-7 breast carcinoma and HT-29 colon carcinoma cells were studied. RESULTS: We show that acidic pH significantly potentiates toxicity of DSF/Cu(2+) complex to breast and colon cancer cells. This phenomenon is associated with changes in cell metabolism, altered Akt kinase and NFκB activity and increased reactive oxygen species production. CONCLUSION: Specific pH of tumor microenvironment enhances cytotoxicity of DSF/Cu(2+) to breast and colon cancer cells.
- MeSH
- antitumorózní látky chemická syntéza chemie toxicita MeSH
- buňky HT-29 MeSH
- disulfiram chemie MeSH
- fosforylace MeSH
- komplexní sloučeniny chemická syntéza chemie toxicita MeSH
- koncentrace vodíkových iontů MeSH
- lidé MeSH
- měď chemie MeSH
- MFC-7 buňky MeSH
- nádorové mikroprostředí účinky léků MeSH
- nádory prsu metabolismus patologie MeSH
- nádory tračníku metabolismus patologie MeSH
- NF-kappa B metabolismus MeSH
- proliferace buněk účinky léků MeSH
- protoonkogenní proteiny c-akt metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Dysfunction of the carnitine system in non-tumour tissue following anticancer therapy has been reported. In this setting, supplementation with carnitine derivatives might increase the general metabolic activity of normal cells so that they might better withstand the adverse effects of chemotherapy aimed at tumour cells. Here we investigated the effect of acetyl-L-carnitine (ALC) alone and in combination with the antineoplastic agent mitoxantrone (MX) in an animal cancer model. METHODS: The effects of MX and MX-ALC were assessed based on gain or loss of body weight and on local growth of a solid form of Ehrlich tumour inoculated into mice. We also performed biochemical analyses like serum activities of some enzymes signalling the functioning of the liver, aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Total protein, albumin and bilirubin were also determined in serum. Under favourable conditions, the Ehrlich tumour readily forms metastases, and this is the reason why we performed histological studies of samples of both the liver and heart in order to identify changes that may have mediated the observed effect of the treatment. In addition to those studies, the survival time of treated animals against controls was also noted. RESULTS: MX monotherapy was associated with lower body weight gain, fewer metastases, smaller tumour size, and lower dissemination. ALC alone promoted survival, but had no potentiating effect on MX therapy in terms of survival. Serum biochemistry changes associated with MX-ALC treatment consisted of a significant (p < 0.05) increase in AST with MX at 6 or 9 mg·kg(-1) plus ALC 200 mg·kg(-1) and a significant (p < 0.05) reduction in total protein compared to the corresponding MX group; serum albumin and bilirubin remained unchanged. CONCLUSION: ALC in combination with MX, regardless of the dose of MX, led to higher occurrences of metastases with dissemination to the kidneys, lungs, heart, and mediastinum compared to MX treatment alone. These histological findings indicate that ALC is inappropriate to combine with MX in the treatment of a solid cancer. The protective effect of ALC in combination therapy with the cytostatic drug MX was not supported in this study by our findings that the agent did not improve the therapeutic outcomes of MX therapy.
- MeSH
- acylkarnitin terapeutické užití MeSH
- antitumorózní látky terapeutické užití MeSH
- bilirubin krev MeSH
- Ehrlichův tumor farmakoterapie patologie MeSH
- experimentální nádory jater farmakoterapie patologie MeSH
- mitoxantron terapeutické užití MeSH
- myši MeSH
- sérový albumin analýza MeSH
- tělesná hmotnost MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: The aim of this basic study was to investigate by scanning electron microscopy the effects of cytoskeleton inhibitors on conidiogenesis and capsule in the yeast Fellomyces fuzhouensis CBS 8243, related to Cryptococcus neoformans. METHODS: Cells were treated by methyl benzimidazole-2-ylcarbamate (BCM) and latrunculin A (LAT) in yeast extract peptone dextrose medium and examined by scanning electron microscopy. RESULTS: During conidiogenesis, mother cells covered by capsule formed hypha-like stalks and at the hyphal tip yeast-like conidium developed. LAT blocked both stages of conidiogenesis. Inhibited mother cells and conidia became spherical and their capsule disappeared. BCM did not block formation of conidia that were neckless, or affect capsule. Combined application of LAT and BCM blocked both stages of conidiogenesis, cells became spherical and their capsule disappeared. CONCLUSION: Yeast cells with disrupted actin cytoskeleton do not reproduce by conidiogenesis and do not retain inherited cell shape and capsule.
- MeSH
- Basidiomycota účinky léků ultrastruktura MeSH
- bicyklické sloučeniny heterocyklické farmakologie MeSH
- cytoskelet účinky léků ultrastruktura MeSH
- mikroskopie elektronová rastrovací metody MeSH
- spory hub účinky léků ultrastruktura MeSH
- thiazolidiny farmakologie MeSH
- tvar buňky účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
BACKGROUND: Fluorescence correlation spectroscopy (FCS) can be used for the determination of diffusion coefficients of single molecules. Since diffusion coefficients are correlated with size and shape of the labeled species, FCS provides information on conformational changes in plasmids aggregates. METHODS: A 10-kbp plasmid stained with PicoGreen was condensed by spermine or liposomes formulated from cationic lipid and egg phosphatidylcholine. RESULTS: The diffusion coefficient of DNA increases from 1.0 x 10(-12) m2/s to 3.2 x 10(-12) m2/s by the addition of spermine, whereas the addition of cationic liposomes leads to complexes characterized by diffusion coefficients with values ranging from 1.7 to 1.9 x 10(-12) m2/s. CONCLUSIONS: FCS experiments allow determining the diffusion coefficients of DNA-containing aggregates which provide information regarding the topology and homogeneity of the aggregate.
The diagnosis and assessment of the severity of intestinal mucosal damage in cancer patients treated with cytotoxic drugs still rely on anamnestic data. There is cumulative evidence that measurement of intestinal permeability may represent a sensitive indicator of intestinal damage by cytotoxic agents. The intestinal permeability testing is based on differential permeability of tight junctions along the crypt-villus axis to nonmetabolized sugars. Cytotoxic drugs induce flattening of villi, leading to increased exposure of luminal contents to crypts and increased disaccharide absorption. An increased disaccharide/monosaccharide ratio and decreased xylose absorption have been described in patients treated with different cytotoxic drugs across a spectrum of malignant tumors that correlated with clinical manifestations, and were used to monitor the effect of therapeutic interventions. Copyright 2005 S. Karger AG, Basel.
- MeSH
- antitumorózní látky škodlivé účinky MeSH
- financování organizované MeSH
- lidé MeSH
- mukozitida diagnóza chemicky indukované MeSH
- nádory farmakoterapie komplikace MeSH
- nemoci střev diagnóza chemicky indukované MeSH
- permeabilita MeSH
- střevní sliznice imunologie metabolismus účinky léků MeSH
- Check Tag
- lidé MeSH
- MeSH
- dospělí MeSH
- infekce získané v komunitě farmakoterapie MeSH
- lidé středního věku MeSH
- lidé MeSH
- obstrukční plicní nemoci farmakoterapie MeSH
- ofloxacin aplikace a dávkování MeSH
- pneumonie farmakoterapie MeSH
- rozvrh dávkování léků MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- multicentrická studie MeSH
