Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults and has a poor prognosis. Complex genetic alterations and the protective effect of the blood-brain barrier (BBB) have so far hampered effective treatment. Here, we investigated the cytotoxic effects of heat shock protein 90 (HSP90) inhibitors, geldanamycin (GDN) and 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin), in a panel of glioma tumor cell lines with various genetic alterations. We also assessed the ability of the main drug transporters, ABCB1 and ABCG2, to efflux GDN and 17-AAG. We found that GDN and 17-AAG induced extensive cell death with the morphological and biochemical hallmarks of apoptosis in all studied glioma cell lines at sub-micro-molar and nanomolar concentrations. Moderate efflux efficacy of GDN and 17-AAG mediated by ABCB1 was observed. There was an insignificant and low efflux efficacy of GDN and 17-AAG mediated by ABCG2. Conclusion: GDN and 17-AAG, in particular, exhibited strong proapoptotic effects in glioma tumor cell lines irrespective of genetic alterations. GDN and 17-AAG appeared to be weak substrates of ABCB1 and ABCG2. Therefore, the BBB would compromise their cytotoxic effects only partially. We hypothesize that GBM patients may benefit from 17-AAG either as a single agent or in combination with other drugs.

• Klíčová slova
• ABC transporters, apoptosis, blood brain barrier, human glioma tumor cell panel, multidrug resistance, tanespimycin,
• Publikační typ
• časopisecké články MeSH

The synthetic curcumin analogue, 3,5-bis[(2-fluorophenyl)methylene]-4-piperidinone (EF-24), suppresses NF-κB activity and exhibits antiproliferative effects against a variety of cancer cells in vitro. Recently, it was reported that EF-24-induced apoptosis was mediated by a redox-dependent mechanism. Here, we studied the effects of N-acetylcysteine (NAC) on EF-24-induced cell death. We also addressed the question of whether the main drug transporters, ABCB1 and ABCG2, affect the cytotoxic of EF-24. We observed that EF-24 induced cell death with apoptotic hallmarks in human leukemia K562 cells. Importantly, the loss of cell viability was preceded by production of reactive oxygen species (ROS), and by a decrease of reduced glutathione (GSH). However, neither ROS production nor the decrease in GSH predominantly contributed to the EF-24-induced cell death. We found that EF-24 formed an adduct with GSH, which is likely the mechanism contributing to the decrease of GSH. Although NAC abrogated ROS production, decreased GSH and prevented cell death, its protective effect was mainly due to a rapid conversion of intra- and extra-cellular EF-24 into the EF-24-NAC adduct without cytotoxic effects. Furthermore, we found that neither overexpression of ABCB1 nor ABCG2 reduced the antiproliferative effects of EF-24. In conclusion, a redox-dependent-mediated mechanism only marginally contributes to the EF-24-induced apoptosis in K562 cells. The main mechanism of NAC protection against EF-24-induced apoptosis is conversion of cytotoxic EF-24 into the noncytotoxic EF-24-NAC adduct. Neither ABCB1 nor ABCG2 mediated resistance to EF-24.

• Klíčová slova
• EF-24-GSH adduct, EF-24-NAC adduct, K562 cells, NF-κB, Nrf2,
• MeSH
• ABC transportér z rodiny G, člen 2 genetika   metabolismus   MeSH
• acetylcystein metabolismus   MeSH
• apoptóza účinky léků   MeSH
• benzylidenové deriváty farmakologie   MeSH
• glutathion metabolismus   MeSH
• leukemie metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• oxidační stres * MeSH
• P-glykoproteiny genetika   metabolismus   MeSH
• piperidony farmakologie   MeSH
• protinádorové látky farmakologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 3,5-bis(2-fluorobenzylidene)piperidin-4-one MeSH Prohlížeč
• ABC transportér z rodiny G, člen 2 MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• acetylcystein MeSH
• benzylidenové deriváty MeSH
• glutathion MeSH
• nádorové proteiny MeSH
• P-glykoproteiny MeSH
• piperidony MeSH
• protinádorové látky MeSH
• reaktivní formy kyslíku MeSH