Mitochondria play a pivotal role in apoptosis: permeabilization of the outer mitochondrial membrane and the release of pro-apoptotic proteins from the intermembrane space of mitochondria are regarded as the key event in apoptosis induction. Here we demonstrate how non-toxic doses of the mitochondrial Complex II inhibitor thenoyltrifluoroacetone (TTFA), which specifically inhibits the ubiquinone-binding site of succinate dehydrogenase (SDH), synergistically stimulated cell death, induced by harmless doses of cisplatin in a panel of chemoresistant neuroblastoma cell lines. Apoptotic cell death was confirmed by cytochrome c release from the mitochondria, cleavage of poly ADP-ribose polymerase, processing of caspase-3, which is an important executive enzyme in apoptosis, and caspase-3-like activity. Methyl malonate, an inhibitor of the SDHA subunit partially reversed apoptosis stimulated by TTFA in SK-N-BE(2) neuroblastoma cells (NB), indicating that sensitization requires oxidation of succinate. In contrast, in IMR-32 NB cells, the same concentrations of TTFA markedly suppressed cisplatin-induced apoptosis. Comparison of oxygen consumption in cisplatin-resistant SK-N-BE(2) and cisplatin-sensitive IMR-32 cells clearly demonstrated impaired Complex II activity in IMR-32 cells. We also found that in SK-N-BE(2) cells co-treatment with cisplatin and TTFA markedly stimulated formation of reactive oxygen species (ROS), whereas in IMR cells, cisplatin-mediated ROS production was attenuated by TTFA, which explains apoptosis suppression in these cells. Thus, functionally active SDH is a prerequisite for the ROS-mediated sensitization to treatment by TTFA.
- MeSH
- antitumorózní látky farmakologie MeSH
- apoptóza účinky léků MeSH
- chemorezistence MeSH
- cílená molekulární terapie * MeSH
- cisplatina farmakologie MeSH
- kyselina jantarová metabolismus MeSH
- léky antitumorózní - screeningové testy MeSH
- lidé MeSH
- mitochondrie účinky léků enzymologie MeSH
- nádorové buněčné linie MeSH
- nádorové proteiny antagonisté a inhibitory MeSH
- neuroblastom patologie MeSH
- oxidace-redukce MeSH
- reaktivní formy kyslíku metabolismus MeSH
- respirační komplex II antagonisté a inhibitory MeSH
- spotřeba kyslíku účinky léků MeSH
- superoxidy metabolismus MeSH
- synergismus léků MeSH
- thenoyltrifluoraceton farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid present in fish oil, may exert cytotoxic and/or cytostatic effects on colon cancer cells when applied individually or in combination with some anticancer drugs. Here we demonstrate a selective ability of subtoxic doses of DHA to enhance antiproliferative and apoptotic effects of clinically useful cytokine TRAIL (tumor necrosis factor-related apoptosis inducing ligand) in cancer but not normal human colon cells. DHA-mediated stimulation of TRAIL-induced apoptosis was associated with extensive engagement of mitochondrial pathway (Bax/Bak activation, drop of mitochondrial membrane potential, cytochrome c release), activation of endoplasmic reticulum stress response (CHOP upregulation, changes in PERK level), decrease of cellular inhibitor of apoptosis protein (XIAP, cIAP1) levels and significant changes in sphingolipid metabolism (intracellular levels of ceramides, hexosyl ceramides, sphingomyelines, sphingosines; HPLC/MS/MS). Interestingly, we found significant differences in representation of various classes of ceramides (especially C16:0, C24:1) between the cancer and normal colon cells treated with DHA and TRAIL, and suggested their potential role in the regulation of the cell response to the drug combination. These study outcomes highlight the potential of DHA for a new combination therapy with TRAIL for selective elimination of colon cancer cells via simultaneous targeting of multiple steps in apoptotic pathways.
- MeSH
- adenokarcinom genetika metabolismus patologie MeSH
- apoptóza účinky léků genetika MeSH
- cytochromy c sekrece MeSH
- inhibitory apoptózy MeSH
- kinasa eIF-2 genetika metabolismus MeSH
- kyseliny dokosahexaenové farmakologie MeSH
- lidé MeSH
- membránový potenciál mitochondrií účinky léků MeSH
- mitochondrie účinky léků metabolismus MeSH
- nádorové buněčné linie MeSH
- nádory tračníku genetika metabolismus patologie MeSH
- protein Bak genetika metabolismus MeSH
- protein TRAIL farmakologie MeSH
- protein X asociovaný s bcl-2 genetika metabolismus MeSH
- regulace genové exprese u nádorů * MeSH
- sfingolipidy chemie klasifikace metabolismus MeSH
- signální transdukce MeSH
- stres endoplazmatického retikula účinky léků MeSH
- synergismus léků MeSH
- transkripční faktor CHOP genetika metabolismus MeSH
- X-vázaný inhibitor apoptózy genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In search for novel strategies in colon cancer treatment, we investigated the unique ability of platinum(IV) complex LA-12 to efficiently enhance the killing effects of tumor necrosis factor-related apoptosis inducing ligand (TRAIL), and compared it with the sensitizing action of cisplatin. We provide the first evidence that LA-12 primes human colon cancer cells for TRAIL-induced cytotoxicity by p53-independent activation of the mitochondrial apoptotic pathway. The cooperative action of LA-12 and TRAIL was associated with stimulation of Bax/Bak activation, drop of mitochondrial membrane potential, caspase-9 activation, and a shift of the balance among Bcl-2 family proteins in favor of the pro-apoptotic members. In contrast to cisplatin, LA-12 was a potent inducer of ERK-mediated Noxa and BimL protein upregulation, and more effectively enhanced TRAIL-induced apoptosis in the absence of Bax. The cooperative action of LA-12 and TRAIL was augmented following the siRNA-mediated silencing of Mcl-1 in both Bax proficient/deficient cells. We newly demonstrated that LA-12 induced ERK-mediated c-Myc upregulation, and proved that c-Myc silencing inhibited the mitochondrial activation and apoptosis in colon cancer cells treated with LA-12 and TRAIL. The LA-12-mediated sensitization to TRAIL-induced apoptosis was demonstrated in several colon cancer cell lines, further underscoring the general relevance of our findings. The selective action of LA-12 was documented by preferential priming of cancer but not normal colon cancer cells to TRAIL killing effects. Our work highlights the promising potential of LA-12 over cisplatin to enhance the colon cancer cell sensitivity to TRAIL-induced apoptosis, and provides new mechanistic insights into their cooperative action.
- MeSH
- amantadin analogy a deriváty farmakologie MeSH
- antitumorózní látky farmakologie MeSH
- apoptóza účinky léků genetika MeSH
- cisplatina farmakologie MeSH
- geny p53 MeSH
- HCT116 buňky účinky léků MeSH
- lidé MeSH
- membránový potenciál mitochondrií účinky léků MeSH
- mitochondrie účinky léků metabolismus MeSH
- nádorové buňky kultivované MeSH
- nádory tračníku farmakoterapie metabolismus patologie MeSH
- organoplatinové sloučeniny farmakologie MeSH
- protein Bak metabolismus MeSH
- protein TRAIL metabolismus farmakologie MeSH
- protein X asociovaný s bcl-2 genetika metabolismus MeSH
- protoonkogenní proteiny c-bcl-2 metabolismus MeSH
- protoonkogenní proteiny c-myc genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Intestinal homeostasis is precisely regulated by a number of endogenous regulatory molecules but significantly influenced by dietary compounds. Malfunction of this system may result in chronic inflammation and cancer. Dietary essential n-3 polyunsaturated fatty acids (PUFAs) and short-chain fatty acid butyrate produced from fibre display anti-inflammatory and anticancer activities. Both compounds were shown to modulate the production and activities of TNF family cytokines. Cytokines from the TNF family (TNF- α, TRAIL, and FasL) have potent inflammatory activities and can also regulate apoptosis, which plays an important role in cancer development. The results of our own research showed enhancement of apoptosis in colon cancer cells by a combination of either docosahexaenoic acid (DHA) or butyrate with TNF family cytokines, especially by promotion of the mitochondrial apoptotic pathway and modulation of NF κ B activity. This review is focused mainly on the interaction of dietary PUFAs and butyrate with these cytokines during colon inflammation and cancer development. We summarised recent knowledge about the cellular and molecular mechanisms involved in such effects and outcomes for intestinal cell behaviour and pathologies. Finally, the possible application for the prevention and therapy of colon inflammation and cancer is also outlined.
- MeSH
- apoptóza MeSH
- butyráty metabolismus MeSH
- cytokiny metabolismus MeSH
- dieta MeSH
- kolon patologie MeSH
- kyseliny dokosahexaenové metabolismus MeSH
- lidé MeSH
- mitochondrie patologie MeSH
- myši MeSH
- nádory metabolismus MeSH
- nenasycené mastné kyseliny metabolismus MeSH
- NF-kappa B metabolismus MeSH
- střeva metabolismus MeSH
- tumor nekrotizující faktory metabolismus MeSH
- zánět metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: Experimental, epidemiological and clinical data substantiate the beneficial role of n-3 polyunsaturated fatty acids (PUFAs) in preventing inflammation and cancer of the colon. This review covers the unsaturated docosahexaenoic fatty acid (DHA), describes some of its important cellular and molecular mechanisms, its interaction with another dietary lipid, butyrate and with endogenous apoptotic regulators of the tumour necrosis factor (TNF) family. We also discuss the clinical impact of this knowledge and the use of these lipids in colon cancer prevention and treatment. RESULTS: From the literature, DHA has been shown to suppress the growth, induce apoptosis in colon cancer cells in vitro and decrease the incidence and growth of experimental tumours in vivo. Based on these data and our own experimental results, we describe and discuss the possible mechanisms of DHA anticancer effects at various levels of cell organization. We show that DHA can sensitize colon cancer cells to other chemotherapeutic/chemopreventive agents and affect the action of physiological apoptotic regulators of the TNF family. CONCLUSION: Use of n-3 PUFAs could be a relatively non-toxic form of supportive therapy for improving colon cancer treatment and slowing down or preventing its recurrence. However, it is necessary to use them with caution, based on solid scientific evidence of their mechanisms of action from the molecular to the cellular and organism levels.
- MeSH
- antitumorózní látky farmakologie MeSH
- apoptóza účinky léků MeSH
- kolon cytologie účinky léků MeSH
- kyseliny dokosahexaenové farmakologie fyziologie MeSH
- lidé MeSH
- nádory tračníku patologie MeSH
- proliferace buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
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
