Intragenic ERG deletions occur in 3-5% of B-cell precursor acute lymphoblastic leukemia, specifically in B-other subtype lacking the classifying genetic lesions. They represent the only genetic lesion described so far present in the majority of cases clustering into a subgroup of B-other subtype characterized by a unique gene expression profile, probably sharing a common, however, not yet fully described, biological background. We aimed to elucidate whether ERG deletions could drive the specific biology of this ERG-related leukemia subgroup through expression of aberrant or decreased expression of wild type ERG isoforms. We showed that leukemic cells with endogenous ERG deletion express an aberrant transcript translated into two proteins in transfected cell lines and that one of these proteins colocalizes with wild type ERG. However, we did not confirm expression of the proteins in acute lymphoblastic leukemia cases with endogenous ERG deletion. ERG deletions resulted in significantly lower expression of wild type ERG transcripts compared to B-other cases without ERG deletion. However, cases with subclonal ERG deletion, clustering to the same ERG deletion associated subgroup, presented similar levels of wild type ERG as cases without ERG deletion. In conclusion, our data suggest that neither the expression of aberrant proteins from internally deleted allele nor the reduced expression of wild type ERG seem to provide a plausible explanation of the specific biology of ERG -related leukemia subgroup.
Cancer cells have a high iron requirement and many experimental studies, as well as clinical trials, have demonstrated that iron chelators are potential anti-cancer agents. The ligand, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT), demonstrates both potent anti-neoplastic and anti-retroviral properties. In this study, Bp4eT and its recently identified amidrazone and semicarbazone metabolites were examined and compared with respect to their anti-proliferative activity towards cancer cells (HL-60 human promyelocytic leukemia, MCF-7 human breast adenocarcinoma, HCT116 human colon carcinoma and A549 human lung adenocarcinoma), non-cancerous cells (H9c2 neonatal rat-derived cardiomyoblasts and 3T3 mouse embryo fibroblasts) and their interaction with intracellular iron pools. Bp4eT was demonstrated to be a highly potent and selective anti-neoplastic agent that induces S phase cell cycle arrest, mitochondrial depolarization and apoptosis in MCF-7 cells. Both semicarbazone and amidrazone metabolites showed at least a 300-fold decrease in cytotoxic activity than Bp4eT towards both cancer and normal cell lines. The metabolites also lost the ability to: (1) promote the redox cycling of iron; (2) bind and mobilize iron from labile intracellular pools; and (3) prevent 59Fe uptake from 59Fe-labeled transferrin by MCF-7 cells. Hence, this study demonstrates that the highly active ligand, Bp4eT, is metabolized to non-toxic and pharmacologically inactive analogs, which most likely contribute to its favorable pharmacological profile. These findings are important for the further development of this drug candidate and contribute to the understanding of the structure-activity relationships of these agents.
- MeSH
- buněčná smrt účinky léků MeSH
- buněčné linie MeSH
- chelátory železa chemie farmakologie MeSH
- kontrolní body fáze S buněčného cyklu účinky léků MeSH
- lidé MeSH
- metabolické sítě a dráhy účinky léků MeSH
- mitochondrie metabolismus patologie MeSH
- nádorové buněčné linie MeSH
- oxidace-redukce účinky léků MeSH
- proliferace buněk účinky léků MeSH
- protinádorové látky chemie farmakologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- semikarbazony chemie metabolismus farmakologie toxicita MeSH
- thiosemikarbazony chemie metabolismus farmakologie toxicita MeSH
- železo chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Salicylaldehyde isonicotinoyl hydrazone (SIH) is a lipophilic, tridentate iron chelator with marked anti-oxidant and modest cytotoxic activity against neoplastic cells. However, it has poor stability in an aqueous environment due to the rapid hydrolysis of its hydrazone bond. In this study, we synthesized a series of new SIH analogs (based on previously described aromatic ketones with improved hydrolytic stability). Their structure-activity relationships were assessed with respect to their stability in plasma, iron chelation efficacy, redox effects and cytotoxic activity against MCF-7 breast adenocarcinoma cells. Furthermore, studies assessed the cytotoxicity of these chelators and their ability to afford protection against hydrogen peroxide-induced oxidative injury in H9c2 cardiomyoblasts. The ligands with a reduced hydrazone bond, or the presence of bulky alkyl substituents near the hydrazone bond, showed severely limited biological activity. The introduction of a bromine substituent increased ligand-induced cytotoxicity to both cancer cells and H9c2 cardiomyoblasts. A similar effect was observed when the phenolic ring was exchanged with pyridine (i.e., changing the ligating site from O, N, O to N, N, O), which led to pro-oxidative effects. In contrast, compounds with long, flexible alkyl chains adjacent to the hydrazone bond exhibited specific cytotoxic effects against MCF-7 breast adenocarcinoma cells and low toxicity against H9c2 cardiomyoblasts. Hence, this study highlights important structure-activity relationships and provides insight into the further development of aroylhydrazone iron chelators with more potent and selective anti-neoplastic effects.
- MeSH
- aldehydy chemie farmakologie toxicita MeSH
- antioxidancia chemie farmakologie MeSH
- buněčné linie MeSH
- chelátory železa chemie farmakologie MeSH
- hydrazony chemie farmakologie toxicita MeSH
- lidé MeSH
- MFC-7 buňky MeSH
- myoblasty účinky léků MeSH
- oxidační stres účinky léků MeSH
- peroxid vodíku toxicita MeSH
- protinádorové látky chemie toxicita MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Recent studies have demonstrated that several chelators possess marked potential as potent anti-neoplastic drugs and as agents that can ameliorate some of the adverse effects associated with standard chemotherapy. Anti-cancer treatment employs combinations of several drugs that have different mechanisms of action. However, data regarding the potential interactions between iron chelators and established chemotherapeutics are lacking. Using estrogen receptor-positive MCF-7 breast cancer cells, we explored the combined anti-proliferative potential of four iron chelators, namely: desferrioxamine (DFO), salicylaldehyde isonicotinoyl hydrazone (SIH), (E)-N'-[1-(2-hydroxy-5-nitrophenyl)ethyliden] isonicotinoyl hydrazone (NHAPI), and di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), plus six selected anti-neoplastic drugs. These six agents are used for breast cancer treatment and include: paclitaxel, 5-fluorouracil, doxorubicin, methotrexate, tamoxifen and 4-hydroperoxycyclophosphamide (an active metabolite of cyclophosphamide). Our quantitative chelator-drug analyses were designed according to the Chou-Talalay method for drug combination assessment. All combinations of these agents yielded concentration-dependent, anti-proliferative effects. The hydrophilic siderophore, DFO, imposed antagonism when used in combination with all six anti-tumor agents and this antagonistic effect increased with increasing dose. Conversely, synergistic interactions were observed with combinations of the lipophilic chelators, NHAPI or Dp44mT, with doxorubicin and also the combinations of SIH, NHAPI or Dp44mT with tamoxifen. The combination of Dp44mT with anti-neoplastic agents was further enhanced following formation of its redox-active iron and especially copper complexes. The most potent combinations of Dp44mT and NHAPI with tamoxifen were confirmed as synergistic using another estrogen receptor-expressing breast cancer cell line, T47D, but not estrogen receptor-negative MDA-MB-231 cells. Furthermore, the synergy of NHAPI and tamoxifen was confirmed using MCF-7 cells by electrical impedance data, a mitochondrial inner membrane potential assay and cell cycle analyses. This is the first systematic investigation to quantitatively assess interactions between Fe chelators and standard chemotherapies using breast cancer cells. These studies are vital for their future clinical development.
- MeSH
- aldehydy farmakologie MeSH
- chelátory železa farmakologie MeSH
- cyklofosfamid analogy a deriváty MeSH
- deferoxamin farmakologie MeSH
- doxorubicin MeSH
- fluoruracil MeSH
- hydrazony farmakologie MeSH
- lidé MeSH
- methotrexát MeSH
- MFC-7 buňky MeSH
- paclitaxel MeSH
- proliferace buněk účinky léků MeSH
- protinádorové látky farmakologie MeSH
- protokoly protinádorové kombinované chemoterapie farmakologie MeSH
- synergismus léků MeSH
- tamoxifen MeSH
- thiosemikarbazony farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Salicylaldehyde isonicotinoyl hydrazone (SIH) is a lipophilic, orally-active tridentate iron chelator providing both effective protection against various types of oxidative stress-induced cellular injury and anticancer action. However, the major limitation of SIH is represented by its labile hydrazone bond that makes it prone to plasma hydrolysis. Recently, nine new SIH analogues derived from aromatic ketones with improved hydrolytic stability were developed. Here we analyzed their antiproliferative potential in MCF-7 breast adenocarcinoma and HL-60 promyelocytic leukemia cell lines. Seven of the tested substances showed greater selectivity than the parent agent SIH towards the latter cancer cell lines compared to non-cancerous H9c2 cardiomyoblast-derived cells. The tested chelators induced a dose-dependent dissipation of the inner mitochondrial membrane potential, an induction of apoptosis as evidenced by Annexin V positivity or significant increases of activities of caspases 3, 7, 8 and 9 and cell cycle arrest. With the exception of nitro group-bearing NHAPI, the studies of iron complexes of the chelators confirmed the crucial role of iron in the mechanism of their antiproliferative action. Finally, all the assayed chelators inhibited the oxidation of ascorbate by iron ions indicating lack of redox activity of the chelator-iron complexes. In conclusion, this study identified several important design criteria for improvement of the antiproliferative selectivity of the aroylhydrazone iron chelators. Several of the novel compounds--in particular the ethylketone-derived HPPI, NHAPI and acetyl-substituted A2,4DHAPI--merit deeper investigation as promising potent and selective anticancer agents.
- MeSH
- aldehydy chemie farmakologie MeSH
- apoptóza účinky léků MeSH
- buněčný cyklus účinky léků MeSH
- chelátory železa chemie farmakologie MeSH
- deferoxamin farmakologie MeSH
- HL-60 buňky MeSH
- hydrazony chemie farmakologie MeSH
- kaspasy metabolismus MeSH
- ketony chemie MeSH
- kyselina askorbová metabolismus MeSH
- lidé MeSH
- membránový potenciál mitochondrií účinky léků MeSH
- nádorové buněčné linie MeSH
- oxidace-redukce MeSH
- protinádorové látky chemie farmakologie MeSH
- screeningové testy protinádorových léčiv MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
