TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) can selectively trigger apoptosis in various cancer cell types. However, many cancer cells are resistant to death receptor-mediated apoptosis. Combination therapy with platinum complexes may affect TRAIL-induced signaling via modulation of various steps in apoptotic pathways. Here, we show that cisplatin or a more potent platinum(IV) complex LA-12 used in 20-fold lower concentration enhanced killing effects of TRAIL in human colon and prostate cancer cell lines via stimulation of caspase activity and overall apoptosis. Both platinum complexes increased DR5 surface expression in colon cancer cells. Small interfering RNA-mediated DR5 silencing rescued cells from sensitizing effects of platinum drugs on TRAIL-induced caspase-8 activation and apoptosis, showing the functional importance of DR5 in the effects observed. In addition, both cisplatin and LA-12 triggered the relocalization of DR4 and DR5 receptors to lipid rafts and accelerated internalization of TRAIL, which may also affect TRAIL signaling. Collectively, modulations of the initial steps of the extrinsic apoptotic pathway at the level of DR5 and plasma membrane are important for sensitization of colon and prostate cancer cells to TRAIL-induced apoptosis mediated by LA-12 and cisplatin.

• MeSH
• amantadin * analogy a deriváty   farmakologie   MeSH
• apoptóza * fyziologie   účinky léků   MeSH
• cisplatina * farmakologie   MeSH
• fluorescenční protilátková technika MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory * metabolismus   MeSH
• organoplatinové sloučeniny * farmakologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• protein TRAIL * metabolismus   MeSH
• průtoková cytometrie MeSH
• RNA interference MeSH
• separace buněk MeSH
• signální transdukce fyziologie   účinky léků   MeSH
• TRAIL receptory metabolismus   MeSH
• transport proteinů účinky léků   MeSH
• western blotting MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

BACKGROUND: LA-12 is a new platinum (IV) drug with promising cytotoxic effects in a wide range of cancer cell lines. Its confluence-dependent effects were compared with cisplatin (CDDP) and oxaliplatin (L-OHP) in HT-29 cells. MATERIALS AND METHODS: Cytotoxicity was determined by MTT test, eosin exclusion assay, and cell number quantification. The cell cycle was analysed using propidium iodide DNA staining (flow cytometry), apoptosis by phosphatidylserine externalisation (annexin-V assay), mitochondrial membrane potential by flow cytometry, nuclear morphology by means of fluorescence microscopy, and PARP cleavage by Western blotting. RESULTS: While L-OHP and CDDP were practically inactive in the subconfluent cell population, LA-12 showed a similar toxicity in both subconfluent and growing populations. All compounds induced apoptosis, although with different potentials. CONCLUSION: LA-12 was able to overcome confluence-dependent resistance of HT-29 cells observed for other platinum compounds, which may have potential therapeutic use in slowly growing tumours.

• MeSH
• adenokarcinom farmakoterapie   MeSH
• amantadin analogy a deriváty   farmakologie   MeSH
• antitumorózní látky farmakologie   MeSH
• apoptóza účinky léků   MeSH
• buněčná adheze účinky léků   MeSH
• buňky HT-29 MeSH
• chemorezistence MeSH
• cisplatina farmakologie   MeSH
• lidé MeSH
• nádory tračníku farmakoterapie   patologie   MeSH
• organoplatinové sloučeniny farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• elektrická impedance diagnostické užití   MeSH
• elektrody MeSH
• léky antitumorózní - screeningové testy metody   MeSH
• polymerázová řetězová reakce s reverzní transkripcí metody   přístrojové vybavení   MeSH
• techniky in vitro MeSH
• vztah mezi dávkou a účinkem léčiva MeSH

Platinum-based complexes are important drugs for the treatment of cancer diseases. Compared to the commonly used Pt(II) compounds cisplatin and oxaliplatin, the recently reported complexes containing Pt(IV) seem to have several advantages; they are safer, can be used orally, have a higher scope of anticancer effect, and do not show cross-resistance to cisplatin. In the first part, cisplatin and oxaliplatin, and satraplatin and LA-12, the Pt(II) and Pt(IV) complexes, respectively, are characterised. Their structures, range of action and side effects are described. In the following part, the mechanisms of their effects are briefly explained, i.e., transport of the active agents to cells, adduct formation, biotransformation pathways, etc. The last part deals with protective mechanisms of the cell, differences in DNA repair mechanisms, and ideas concerning the development of resistance to these drugs.

• MeSH
• antitumorózní látky aplikace a dávkování   škodlivé účinky   terapeutické užití   MeSH
• chemorezistence genetika   imunologie   účinky léků   MeSH
• cisplatina aplikace a dávkování   škodlivé účinky   terapeutické užití   MeSH
• farmakokinetika MeSH
• fenitrotion terapeutické užití   MeSH
• financování organizované MeSH
• glutathion škodlivé účinky   terapeutické užití   MeSH
• lidé MeSH
• nežádoucí účinky léčiv komplikace   MeSH
• organokovové sloučeniny aplikace a dávkování   škodlivé účinky   terapeutické užití   MeSH
• organoplatinové sloučeniny aplikace a dávkování   škodlivé účinky   terapeutické užití   MeSH
• sloučeniny platiny aplikace a dávkování   škodlivé účinky   terapeutické užití   MeSH
• Check Tag
• lidé MeSH

OBJECTIVES: This article is to study the role of G(1)/S regulators in differentiation of pluripotent embryonic cells. MATERIALS AND METHODS: We established a P19 embryonal carcinoma cell-based experimental system, which profits from two similar differentiation protocols producing endodermal or neuroectodermal lineages. The levels, mutual interactions, activities, and localization of G(1)/S regulators were analysed with respect to growth and differentiation parameters of the cells. RESULTS AND CONCLUSIONS: We demonstrate that proliferation parameters of differentiating cells correlate with the activity and structure of cyclin A/E-CDK2 but not of cyclin D-CDK4/6-p27 complexes. In an exponentially growing P19 cell population, the cyclin D1-CDK4 complex is detected, which is replaced by cyclin D2/3-CDK4/6-p27 complex following density arrest. During endodermal differentiation kinase-inactive cyclin D2/D3-CDK4-p27 complexes are formed. Neural differentiation specifically induces cyclin D1 at the expense of cyclin D3 and results in predominant formation of cyclin D1/D2-CDK4-p27 complexes. Differentiation is accompanied by cytoplasmic accumulation of cyclin Ds and CDK4/6, which in neural cells are associated with neural outgrowths. Most phenomena found here can be reproduced in mouse embryonic stem cells. In summary, our data demonstrate (i) that individual cyclin D isoforms are utilized in cells lineage specifically, (ii) that fundamental difference in the function of CDK4 and CDK6 exists, and (iii) that cyclin D-CDK4/6 complexes function in the cytoplasm of differentiated cells. Our study unravels another level of complexity in G(1)/S transition-regulating machinery in early embryonic cells.

• MeSH
• biologické modely MeSH
• buněčná diferenciace MeSH
• buněčný rodokmen MeSH
• cyklin A metabolismus   MeSH
• cyklin D1 MeSH
• cyklin E metabolismus   MeSH
• cyklin-dependentní kinasa 4 metabolismus   MeSH
• cyklin-dependentní kinasa 6 metabolismus   MeSH
• cykliny metabolismus   MeSH
• embryo savčí cytologie   metabolismus   MeSH
• embryonální kmenové buňky metabolismus   MeSH
• financování organizované MeSH
• G1 fáze MeSH
• inhibitor p27 cyklin-dependentní kinasy metabolismus   MeSH
• intracelulární prostor metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• proliferace buněk MeSH
• S fáze MeSH
• transport proteinů MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

Loss of programmed cell death pathways is one of the features of malignancy that complicate the response of cancer cells to a therapy. Activation of alternative cell death pathways offers a promising approach to enhance efficiency of cancer chemotherapy. We analysed programmed cell death pathways of v-myb-transformed BM2 monoblasts induced by arsenic trioxide, cycloheximide and camptothecin with U937 promonocytes as a reference cell line. We show that induced death of BM2 cells is not executed by caspases but rather by alternative cell death pathways. Camptothecin induces the lysosome-dependent cell death, arsenic trioxide induces autophagy, and most of cycloheximide-treated BM2 cells die by necrosis. The fact that alternative cell death pathways can be switched in cells with defects in activation and/or function of caspases suggests that understanding and targeting of these pathways could improve therapy of cancer cells suffering from defective apoptosis.

• MeSH
• antitumorózní látky farmakologie   MeSH
• apoptóza účinky léků   MeSH
• arsenikové přípravky farmakologie   MeSH
• autofagie účinky léků   MeSH
• cykloheximid farmakologie   MeSH
• financování organizované MeSH
• fluorescenční mikroskopie MeSH
• geny myb fyziologie   MeSH
• kamptothecin farmakologie   MeSH
• kaspasy metabolismus   MeSH
• kur domácí MeSH
• lidé MeSH
• nádorová transformace buněk patologie   MeSH
• nekróza MeSH
• oxidy farmakologie   MeSH
• signální transdukce účinky léků   MeSH
• transformované buněčné linie MeSH
• U937 buňky účinky léků   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH

c-Jun is one of the major components of the activating protein-1 (AP-1), the transcription factor that participates in regulation of proliferation, differentiation, and apoptosis. In this study, we explored functional interactions of the c-Jun protein with several regulators of the G1/S transition in serum-deprived v-myb-transformed chicken monoblasts BM2. We show that the c-Jun protein induces expression of cyclin A, thus up-regulating activity of cyclin A-associated cyclin-dependent kinase 2 (CDK2), and causing massive programmed cell death of starved BM2cJUN cells. Specific inhibition of CDK2 suppresses frequency of apoptosis of BM2cJUN cells. We conclude that up-regulation of cyclin A expression and CDK2 activity can represent important link between the c-Jun protein, cell cycle machinery, and programmed cell death pathway in leukemic cells.

• MeSH
• aktivace enzymů MeSH
• akutní monocytární leukemie metabolismus   MeSH
• apoptóza MeSH
• buněčné linie MeSH
• cyklin-dependentní kinasa 2 metabolismus   MeSH
• financování organizované MeSH
• kultivační média bez séra MeSH
• kur domácí MeSH
• nádorová transformace buněk metabolismus   MeSH
• oxidační stres MeSH
• protoonkogenní proteiny c-jun metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

• MeSH
• financování organizované MeSH
• Publikační typ
• abstrakty MeSH

Platinum (IV) derivative with adamantylamine-LA-12-represents a new generation of highly efficient anti-cancer drug derived from cisplatin and is currently in the final stage of phase I clinical trials. Understanding the specific mechanisms of its effects on cell cycle is necessary for defining the mode of action of LA-12. In this study, we characterized the ability of LA-12 to induce cell cycle perturbations in ovarian cancer cell line A2780 as compared to equitoxic cisplatin treatment. LA-12 induced a permanent accumulation of A2780 cells in S phase while cisplatin caused G2/M arrest at 24-h time point, where we also detected an increased expression of Gadd45alpha protein. Although both derivatives induced a rapid increase of p53 expression, this was not associated with a down-regulation of Mdm2 protein. Increased expression of p21(Cip1/WAF1) protein and its association with cyclins A and B1 suggested that this cyclin-dependent kinase inhibitor might contribute significantly to the observed perturbations of cell cycle. The results of this study provide insight into the mechanism of action of platinum-based derivative with adamantylamine on cell cycle in ovarian cancer cells. The differences between effects of LA-12 and cisplatin suggest that more attention should be paid to elucidation of modes of action of novel platinum(IV) complexes at cellular level.

• MeSH
• amantadin aplikace a dávkování   farmakologie   MeSH
• antitumorózní látky farmakologie   MeSH
• buněčný cyklus účinky léků   MeSH
• cisplatina farmakologie   MeSH
• financování organizované MeSH
• karcinom farmakoterapie   metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• nádory vaječníků farmakoterapie   metabolismus   MeSH
• organoplatinové sloučeniny farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• protein X asociovaný s bcl-2 metabolismus   MeSH
• proteiny buněčného cyklu metabolismus   MeSH
• protoonkogenní proteiny c-mdm2 metabolismus   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• srovnávací studie MeSH

The p53 protein can control cell cycle progression, programmed cell death, and differentiation of many cell types. Ectopic expression of p53 can resume capability of cell cycle arrest, differentiation, and apoptosis in various leukemic cell lines. In this work, we expressed human p53 protein in v-Myb-transformed chicken monoblasts. We found that even this protein possessing only 53% amino acid homology to its avian counterpart can significantly alter morphology and physiology of these cells causing the G2-phase cell cycle arrest and early monocytic differentiation. Our results document that the species-specific differences of the p53 molecules, promoters/enhancers, and co-factors in avian and human cells do not interfere with differentiation- and cell cycle arrest promoting capabilites of the p53 tumor suppressor even in the presence of functional v-Myb oncoprotein. The p53-induced differentiation and cell cycle arrest of v-Myb-transformed monoblasts are not associated with apoptosis suggesting that the p53-driven pathways controlling apoptosis and differentiation/proliferation are independent.

• MeSH
• apoptóza genetika   MeSH
• buněčná diferenciace fyziologie   genetika   MeSH
• buněčný cyklus genetika   MeSH
• financování organizované MeSH
• G2 fáze genetika   MeSH
• inhibitory růstu fyziologie   genetika   MeSH
• kur domácí MeSH
• lidé MeSH
• monocyty cytologie   MeSH
• nádorový supresorový protein p53 fyziologie   genetika   MeSH
• onkogenní proteiny v-myb genetika   MeSH
• proliferace buněk MeSH
• signální transdukce genetika   MeSH
• transfekce MeSH
• transformované buněčné linie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH