RESUMO
Targeted protein degradation offers new opportunities to inactivate cancer drivers and has successfully entered the clinic. Ways to induce selective protein degradation include proteolysis targeting chimera (PROTAC) technology and immunomodulatory (IMiDs) / next-generation Cereblon (CRBN) E3 ligase modulating drugs (CELMoDs). Here, we aimed to develop a MYC PROTAC based on the MYC-MAX dimerization inhibitor 10058-F4 derivative 28RH and Thalidomide, called MDEG-541. We show that a subgroup of gastrointestinal cancer cell lines and primary patient-derived organoids are MDEG-541 sensitive. Although MYC expression was regulated in a CRBN-, proteasome- and ubiquitin-dependent manner, we provide evidence that MDEG-541 induced the degradation of CRBN neosubstrates, including G1 to S phase transition 1/2 (GSPT1/2) and the Polo-like kinase 1 (PLK1). In sum, we have established a CRBN-dependent degrader of relevant cancer targets with activity in gastrointestinal cancers.
Assuntos
Antineoplásicos/farmacologia , Neoplasias Gastrointestinais/tratamento farmacológico , Talidomida/farmacologia , Tiazóis/farmacologia , Ubiquitina-Proteína Ligases/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Neoplasias Gastrointestinais/metabolismo , Neoplasias Gastrointestinais/patologia , Humanos , Estrutura Molecular , Relação Estrutura-Atividade , Talidomida/síntese química , Talidomida/química , Tiazóis/síntese química , Tiazóis/química , Células Tumorais Cultivadas , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Acute myeloid leukemia (AML) with mutations in the FMS-like tyrosine kinase (FLT3) is a clinically unresolved problem. AML cells frequently have a dysregulated expression and activity of epigenetic modulators of the histone deacetylase (HDAC) family. Therefore, we tested whether a combined inhibition of mutant FLT3 and class I HDACs is effective against AML cells. Low nanomolar doses of the FLT3 inhibitor (FLT3i) AC220 and an inhibition of class I HDACs with nanomolar concentrations of FK228 or micromolar doses of the HDAC3 specific agent RGFP966 synergistically induce apoptosis of AML cells that carry hyperactive FLT3 with an internal tandem duplication (FLT3-ITD). This does not occur in leukemic cells with wild-type FLT3 and without FLT3, suggesting a preferential toxicity of this combination against cells with mutant FLT3. Moreover, nanomolar doses of the new FLT3i marbotinib combine favorably with FK228 against leukemic cells with FLT3-ITD. The combinatorial treatments potentiated their suppressive effects on the tyrosine phosphorylation and stability of FLT3-ITD and its downstream signaling to the kinases ERK1/ERK2 and the inducible transcription factor STAT5. The beneficial pro-apoptotic effects of FLT3i and HDACi against leukemic cells with mutant FLT3 are associated with dose- and drug-dependent alterations of cell cycle distribution and DNA damage. This is linked to a modulation of the tumor-suppressive transcription factor p53 and its target cyclin-dependent kinase inhibitor p21. While HDACi induce p21, AC220 suppresses the expression of p53 and p21. Furthermore, we show that both FLT3-ITD and class I HDAC activity promote the expression of the checkpoint kinases CHK1 and WEE1, thymidylate synthase, and the DNA repair protein RAD51 in leukemic cells. A genetic depletion of HDAC3 attenuates the expression of such proteins. Thus, class I HDACs and hyperactive FLT3 appear to be valid targets in AML cells with mutant FLT3.
Assuntos
Leucemia Mieloide Aguda , Apoptose , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Histona Desacetilases/metabolismo , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Inibidores de Proteínas Quinases/farmacologia , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/metabolismoRESUMO
Aberrant epigenetic changes in DNA methylation and histone modification by acetylation or deacetylation regulate the pathogenesis of many diseases. Especially selective inhibitors are getting more and more attention. We recently reported on a new class of potent and selective anti-inflammatory and antirheumatic histone deacetylase 6 (HDAC6) inhibitors (e.g., Marbostat-100). The attachment of a morpholinoethoxy part to the head group dramatically enhances the solubility, in particular the solubility in aqueous solutions, of the lead compound Marbostat-100. Here, we present the enantioselective synthesis of small-molecule compounds based on the tetrahydro-ß-carboline core system with improved solubility, and the influence of the stereochemistry on the biological activity. The enantiomers were synthesized in good enantiomeric excess (ee) purity and were potent and selective HDAC6 inhibitors, whereas the S-derivative S-21 is clearly the eutomer. The potency of our selective HDAC6 inhibitors is demonstrated by Ki values in the range of 0.5-2 nM toward HDAC6, and the selectivity was proved in cellular assays by Western blot analysis taking ac-tubulin as surrogate parameter.
Assuntos
Carbolinas/química , Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/síntese química , Acetilação , Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/farmacologia , Humanos , Estrutura Molecular , Solubilidade , EstereoisomerismoRESUMO
The treatment of acute promyelocytic leukemia (APL) with all-trans retinoic acid (ATRA) induces granulocytic differentiation. This process renders APL cells resistant to cytotoxic chemotherapies. Epigenetic regulators of the histone deacetylases (HDACs) family, which comprise four classes (I-IV), critically control the development and progression of APL. We set out to clarify the parameters that determine the interaction between ATRA and histone deacetylase inhibitors (HDACi). Our assays included drugs against class I HDACs (MS-275, VPA, and FK228), pan-HDACi (LBH589, SAHA), and the novel HDAC6-selective compound Marbostat-100. We demonstrate that ATRA protects APL cells from cytotoxic effects of SAHA, MS-275, and Marbostat-100. However, LBH589 and FK228, which have a superior substrate-inhibitor dissociation constant (Ki) for the class I deacetylases HDAC1, 2, 3, are resistant against ATRA-dependent cytoprotective effects. We further show that HDACi evoke DNA damage, measured as induction of phosphorylated histone H2AX and by the comet assay. The ability of ATRA to protect APL cells from the induction of p-H2AX by HDACi is a readout for the cytoprotective effects of ATRA. Moreover, ATRA increases the fraction of cells in the G1 phase, together with an accumulation of the cyclin-dependent kinase inhibitor p21 and a reduced expression of thymidylate synthase (TdS). In contrast, the ATRA-dependent activation of the transcription factors STAT1, NF-κB, and C/EBP hardly influences the responses of APL cells to HDACi. We conclude that the affinity of HDACi for class I HDACs determines whether such drugs can kill naïve and maturated APL cells.
Assuntos
Inibidores de Histona Desacetilases/farmacologia , Leucemia/tratamento farmacológico , Leucemia/patologia , Tretinoína/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Benzamidas/farmacologia , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Dano ao DNA/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Inibidores de Histona Desacetilases/administração & dosagem , Humanos , Leucemia/metabolismo , NF-kappa B/metabolismo , Piridinas/farmacologia , Fator de Transcrição STAT1/metabolismo , Tretinoína/administração & dosagemRESUMO
Our previously reported HDAC6 inhibitor (HDAC6i) Marbostat-100 (4) has provided many arguments for further clinical evaluation. By the substitution of the acidic hydrogen of 4 for different carbon residues, we were able to generate an all-carbon stereocenter, which significantly improves the hydrolytic stability of the inhibitor. Further asymmetric synthesis has shown that the (S)-configured inhibitors preferentially bind to HDAC6. This led to the highly selective and potent methyl-substituted derivative S-29b, which elicited a long-lasting tubulin hyperacetylation in MV4-11 cells. Finally, a crystal structure of the HDAC6/S-29b complex provided mechanistic explanation for the high potency and stereoselectivity of synthesized compound series.
Assuntos
Carbolinas , Desacetilase 6 de Histona , Inibidores de Histona Desacetilases , Humanos , Carbolinas/química , Carbolinas/farmacologia , Carbolinas/síntese química , Linhagem Celular Tumoral , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Desacetilase 6 de Histona/antagonistas & inibidores , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/química , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/síntese química , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Morfolinas/síntese química , Morfolinas/química , Morfolinas/farmacologiaRESUMO
Hyperactive FMS-like receptor tyrosine kinase-3 mutants with internal tandem duplications (FLT3-ITD) are frequent driver mutations of aggressive acute myeloid leukemia (AML). Inhibitors of FLT3 produce promising results in rationally designed cotreatment schemes. Since FLT3-ITD modulates DNA replication and DNA repair, valid anti-leukemia strategies could rely on a combined inhibition of FLT3-ITD and regulators of cell cycle progression and DNA integrity. These include the WEE1 kinase which controls cell cycle progression, nucleotide synthesis, and DNA replication origin firing. We investigated how pharmacological inhibition of FLT3 and WEE1 affected the survival and genomic integrity of AML cell lines and primary AML cells. We reveal that promising clinical grade and preclinical inhibitors of FLT3 and WEE1 synergistically trigger apoptosis in leukemic cells that express FLT3-ITD. An accumulation of single and double strand DNA damage precedes this process. Mass spectrometry-based proteomic analyses show that FLT3-ITD and WEE1 sustain the expression of the ribonucleotide reductase subunit RRM2, which provides dNTPs for DNA replication. Unlike their strong pro-apoptotic effects on leukemia cells with FLT3-ITD, inhibitors of FLT3 and WEE1 do not damage healthy human blood cells and murine hematopoietic stem cells. Thus, pharmacological inhibition of FLT3-ITD and WEE1 might become an improved, rationally designed therapeutic option.
Assuntos
Apoptose , Proteínas de Ciclo Celular , Dano ao DNA , Leucemia Mieloide Aguda , Inibidores de Proteínas Quinases , Proteínas Tirosina Quinases , Tirosina Quinase 3 Semelhante a fms , Humanos , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/metabolismo , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Apoptose/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/genética , Inibidores de Proteínas Quinases/farmacologia , Linhagem Celular Tumoral , Sinergismo Farmacológico , Animais , Pirazóis , PirimidinonasRESUMO
Several members of the quinazoline class of known tyrosine kinase inhibitors are approved anticancer agents, often showing selectivity for receptors of the HER/ErbB-family. Combining structural elements of this class with the bisindolylmethanone-structure led to a series of novel compounds. These compounds inhibited EGFR in the nanomolar range. Moreover, inhibition of EGFR autophosphorylation in intact A431 cells was shown, with IC(50) values ranging form 0.3-1µM for compound 42, and 0.1-0.3µM for 45. In a panel of 42 human tumor cell lines the sensitivity profile of the novel compounds was shown to be similar to that of the quinazoline class of tyrosine kinase inhibitors lapatinib and erlotinib (Tarceva®).
Assuntos
Antineoplásicos/química , Receptores ErbB/antagonistas & inibidores , Indóis/química , Pirimidinas/química , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Receptores ErbB/metabolismo , Humanos , Indóis/síntese química , Indóis/farmacologia , Fosforilação/efeitos dos fármacos , Pirimidinas/síntese química , Pirimidinas/farmacologia , Quinazolinas/síntese química , Quinazolinas/química , Quinazolinas/farmacologia , Relação Estrutura-AtividadeRESUMO
Internal tandem duplications (ITDs) in the FMS-like tyrosine kinase-3 (FLT3) are causally linked to acute myeloid leukemia (AML) with poor prognosis. Available FLT3 inhibitors (FLT3i) preferentially target inactive or active conformations of FLT3. Moreover, they co-target kinases for normal hematopoiesis, are vulnerable to therapy-associated tyrosine kinase domain (TKD) FLT3 mutants, or lack low nanomolar activity. We show that the tyrosine kinase inhibitor marbotinib suppresses the phosphorylation of FLT3-ITD and the growth of permanent and primary AML cells with FLT3-ITD. This also applies to leukemic cells carrying FLT3-ITD/TKD mutants that confer resistance to clinically used FLT3i. Marbotinib shows high selectivity for FLT3 and alters signaling, reminiscent of genetic elimination of FLT3-ITD. Molecular docking shows that marbotinib fits in opposite orientations into inactive and active conformations of FLT3. The water-soluble marbotinib-carbamate significantly prolongs survival of mice with FLT3-driven leukemia. Marbotinib is a nanomolar next-generation FLT3i that represents a hybrid inhibitory principle.
Assuntos
Leucemia Mieloide Aguda , Inibidores de Proteínas Quinases , Tirosina Quinase 3 Semelhante a fms , Animais , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Camundongos , Simulação de Acoplamento Molecular , Mutação , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidoresRESUMO
Overexpression of MYC is a genuine cancer driver in lymphomas and related to poor prognosis. However, therapeutic targeting of the transcription factor MYC remains challenging. Here, we show that inhibition of the histone deacetylase 6 (HDAC6) using the HDAC6 inhibitor Marbostat-100 (M-100) reduces oncogenic MYC levels and prevents lymphomagenesis in a mouse model of MYC-induced aggressive B-cell lymphoma. M-100 specifically alters protein-protein interactions by switching the acetylation state of HDAC6 substrates, such as tubulin. Tubulin facilitates nuclear import of MYC, and MYC-dependent B-cell lymphoma cells rely on continuous import of MYC due to its high turn-over. Acetylation of tubulin impairs this mechanism and enables proteasomal degradation of MYC. M-100 targets almost exclusively B-cell lymphoma cells with high levels of MYC whereas non-tumor cells are not affected. M-100 induces massive apoptosis in human and murine MYC-overexpressing B-cell lymphoma cells. We identified the heat-shock protein DNAJA3 as an interactor of tubulin in an acetylation-dependent manner and overexpression of DNAJA3 resulted in a pronounced degradation of MYC. We propose a mechanism by which DNAJA3 associates with hyperacetylated tubulin in the cytoplasm to control MYC turnover. Taken together, our data demonstrate a beneficial role of HDAC6 inhibition in MYC-dependent B-cell lymphoma.
Assuntos
Linfoma de Células B , Tubulina (Proteína) , Acetilação , Animais , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Choque Térmico/metabolismo , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Humanos , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/genética , Camundongos , Fatores de Transcrição/metabolismo , Tubulina (Proteína)/metabolismoRESUMO
Combined treatment with tyrosine kinase inhibitors (TKi) and additional drugs is emerging as a promising strategy for cancer therapy. TKi and histone-deacetylase inhibitors (HDI) are two classes of anti-tumor agents with distant mechanisms of action. We have designed and synthesized chimeric compounds, which comprise structural elements of the TKi imatinib, and of prototypical HDI compounds. These compounds retain TKi activity similar to imatinib, exemplified by the inhibition of the platelet-derived growth factor receptor, and c-Kit kinase in intact cells. In addition, the chimeric compounds have in vitro and cellular HDI activity, and potently inhibit growth of cancer cell lines, including that of imatinib-resistant cell lines. Chimeric molecules with combined TKi and HDI activity may simplify combination treatment and be applicable to overcome clinical resistance to TKi single-agent therapy.
Assuntos
Antineoplásicos/uso terapêutico , Inibidores de Histona Desacetilases/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/antagonistas & inibidores , Antineoplásicos/síntese química , Benzamidas , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Inibidores de Histona Desacetilases/síntese química , Humanos , Mesilato de Imatinib , Piperazinas/uso terapêutico , Inibidores de Proteínas Quinases/síntese química , Pirimidinas/uso terapêutico , Receptores do Fator de Crescimento Derivado de Plaquetas/efeitos dos fármacos , Receptores do Fator de Crescimento Derivado de Plaquetas/metabolismoRESUMO
Mutants of the FLT3 receptor tyrosine kinase (RTK) with duplications in the juxtamembrane domain (FLT3-ITD) act as drivers of acute myeloid leukemia (AML). Potent tyrosine kinase inhibitors (TKi) of FLT3-ITD entered clinical trials and showed a promising, but transient success due to the occurrence of secondary drug-resistant AML clones. A further caveat of drugs targeting FLT3-ITD is the co-targeting of other RTKs which are required for normal hematopoiesis. This is observed quite frequently. Therefore, novel drugs are necessary to treat AML effectively and safely. Recently bis(1H-indol-2-yl)methanones were found to inhibit FLT3 and PDGFR kinases. In order to optimize these agents we synthesized novel derivatives of these methanones with various substituents. Methanone 16 and its carbamate derivative 17b inhibit FLT3-ITD at least as potently as the TKi AC220 (quizartinib). Models indicate corresponding interactions of 16 and quizartinib with FLT3. The activity of 16 is accompanied by a high selectivity for FLT3-ITD.
Assuntos
Antineoplásicos/farmacologia , Indóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis/síntese química , Indóis/química , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Tirosina Quinase 3 Semelhante a fms/metabolismoRESUMO
Inhibition of the mutated fms-like tyrosine kinase 3 (FLT3) receptor tyrosine kinase is a promising therapeutic strategy in acute myeloid leukaemia (AML). However, development of resistance to FLT3 tyrosine kinase inhibitors (TKI), such as PKC412A, has been described recently. This observation may have an increasing impact on the duration of response and relapse rates in upcoming clinical trials employing FLT3-TKI. Herein we investigated two representatives of a novel class of FLT3-TKI: Bis(1H-indol-2-yl)methanones. Both compounds effectively induced apoptosis in FLT3-internal tandem duplicate (ITD)-transfected murine myeloid cells and in primary FLT3-ITD positive blasts. Combination of both compounds with chemotherapy revealed synergistic effects in apoptosis assays. The compounds did not show significant toxicity in human bone marrow cells derived from healthy donors. Compound102 overcame resistance to PKC412 within a non-myelotoxic dose-range. Western Blotting experiments of 32D-FLT3-ITD cells showed dose-dependent dephosphorylation of FLT3-ITD and of its downstream targets STAT5, AKT and ERK upon incubation with either compound. In conclusion, bis(1H-indol-2-yl)methanones overcome resistance mediated by FLT3-ITD mutations at position N676 and show strong efficacy in FLT3-ITD-positive cells alone as well as in combination with chemotherapy. We propose that further development of methanone compounds overcoming resistance to currently established FLT3-TKIs is an important step forward to an anticipated need within our future therapeutic algorithm in FLT3-ITD-positive AML.
Assuntos
Antineoplásicos/uso terapêutico , Indóis/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Estaurosporina/análogos & derivados , Sequências de Repetição em Tandem , Tirosina Quinase 3 Semelhante a fms/genética , Apoptose/efeitos dos fármacos , Linhagem Celular , Resistencia a Medicamentos Antineoplásicos , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Estaurosporina/uso terapêutico , Transfecção/métodos , Células Tumorais CultivadasRESUMO
Experiments with cultured mammalian cells represent an in vitro alternative to animal experiments. Fetal calf serum (FCS) is the most commonly used media supplement worldwide. FCS contains a mixture of largely undefined growth factors and cytokines, which support cell proliferation. This undefined nature of FCS is a source of experimental variation, undesired immune responses, possible contaminations, and because of its way of production an ethical concern. Thus, alternative, defined, valid, and reliable media supplements should be characterized in a large number of experiments. Human platelet lysate (hPL) is increasingly appreciated as an alternative to FCS. Since it is unclear whether cells respond differentially to clinically relevant chemotherapeutics inducing replicative stress and DNA damage (Hydroxyurea, Irinotecan), induction of reactive oxygen species (ROS), the tyrosine kinase inhibitor (TKi) Imatinib, and novel epigenetic modifiers belonging to the group of histone deacetylase inhibitors (HDACi), we investigated these issues. Here we show that cancer cells derived from leukemia and colon cancer grow very similarly in culture media with FCS or outdated hPL. Notably, cells have practically identical proteomes under both culture conditions. Moreover, cells grown with FCS or hPL respond equally to all types of drugs and stress conditions that we have tested. In addition, the transfection of blood cells by electroporation can be achieved under both conditions. Furthermore, we reveal that class I HDACs, but not HDAC6, are required for the expression of the pan-leukemic marker WT1 under various culture conditions. Hence, hPL is a moderately priced substitute for FCS in various experimental settings.
Assuntos
Antineoplásicos , Plaquetas/metabolismo , Técnicas de Cultura de Células/métodos , Meios de Cultura/metabolismo , Animais , Células Cultivadas , Humanos , SoroRESUMO
A series of N-(3-(4-(pyridin-3-yl)-1H-imidazol-2-ylamino)phenyl)amides were synthesized and tested for inhibition of PDGFR and FLT3 autophosphorylation. The novel N-(3-(4-(pyridin-3-yl)-1H-imidazol-2-ylamino)phenyl)amides, obtained by replacement of the pyrimidine system in Imatinib (1) with an imidazole ring, exhibit potent inhibitory activity on PDGFR, similar to the parent compound (IC(50) (9e)=0.2 microM; IC(50) Imatinib (1)=0.3 microM). Selectivity hereby seems to be conserved, as shown by the lack of activity on FLT3, a closely related class III receptor tyrosine kinase, which is not affected by the parent compound Imatinib.
Assuntos
Imidazóis/química , Imidazóis/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Receptores do Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Espectroscopia de Ressonância Magnética , Espectrometria de Massas por Ionização por Electrospray , Relação Estrutura-AtividadeRESUMO
Compounds containing 3-bromo-2,5-dihydro-1H-2,5-pyrroledione and indole substructures were found to have antibacterial activity against resistant strains of Staphylococcus aureus and some other Gram positive bacteria. The investigated compounds exhibit minimal inhibition concentrations (MICs) lower than those of common antibiotics like vancomycin or ciprofloxacin. Activity against multiresistant strains suggests a mechanism of action different from common antibiotics. This might be important in circumventing existing resistance mechanisms. Here we report about the antibacterial activity in an extended structure-activity relationship study.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Indóis/farmacologia , Maleimidas/química , Maleimidas/farmacologia , Pirróis/química , Pirróis/farmacologia , Antibacterianos/síntese química , Desenho de Fármacos , Indóis/síntese química , Indóis/química , Maleimidas/síntese química , Testes de Sensibilidade Microbiana , Mycobacterium smegmatis/efeitos dos fármacos , Pirróis/síntese química , Staphylococcus aureus/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Various diseases are related to epigenetic modifications. Histone deacetylases (HDACs) and histone acetyl transferases (HATs) determine the pattern of histone acetylation, and thus are involved in the regulation of gene expression. First generation histone deacetylase inhibitors (HDACi) are unselective, hinder all different kinds of zinc dependent HDACs and additionally cause several side effects. Subsequently, selective HDACi are gaining more and more interest. Especially, selective histone deacetylase 6 inhibitors (HDAC6i) are supposed to be less toxic. Here we present a successful optimization study of tubastatin A, the synthesis and biological evaluation of new inhibitors based on hydroxamic acids linked to various tetrahydro-ß-carboline derivatives. The potency of our selective HDAC6 inhibitors, exhibiting IC50 values in a range of 1-10â¯nM towards HDAC6, was evaluated with the help of a recombinant human HDAC6 enzyme assay. Selectivity was proofed in cellular assays by the hyperacetylation of surrogate parameter α-tubulin in the absence of acetylated histone H3 analyzed by Western Blot. We show that all synthesized compounds, with varies modifications of the rigid cap group, were selective and potent HDAC6 inhibitors.
Assuntos
Carbolinas/farmacologia , Desenho de Fármacos , Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/farmacologia , Animais , Apoptose/efeitos dos fármacos , Carbolinas/síntese química , Carbolinas/química , Ciclo Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Desacetilase 6 de Histona/deficiência , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/química , Humanos , Camundongos , Camundongos Knockout , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Drug resistance is a leading cause for treatment failure in many cancers, including neuroblastoma, the most common solid extracranial childhood malignancy. Previous studies from our lab indicate that histone deacetylase 10 (HDAC10) is important for the homeostasis of lysosomes, i.e. acidic vesicular organelles involved in the degradation of various biomolecules. Here, we show that depleting or inhibiting HDAC10 results in accumulation of lysosomes in chemotherapy-resistant neuroblastoma cell lines, as well as in the intracellular accumulation of the weakly basic chemotherapeutic doxorubicin within lysosomes. Interference with HDAC10 does not block doxorubicin efflux from cells via P-glycoprotein inhibition, but rather via inhibition of lysosomal exocytosis. In particular, intracellular doxorubicin does not remain trapped in lysosomes but also accumulates in the nucleus, where it promotes neuroblastoma cell death. Our data suggest that lysosomal exocytosis under doxorubicin treatment is important for cell survival and that inhibition of HDAC10 further induces DNA double-strand breaks (DSBs), providing additional mechanisms that sensitize neuroblastoma cells to doxorubicin. Taken together, we demonstrate that HDAC10 inhibition in combination with doxorubicin kills neuroblastoma, but not non-malignant cells, both by impeding drug efflux and enhancing DNA damage, providing a novel opportunity to target chemotherapy resistance.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Reparo do DNA , Doxorrubicina/farmacologia , Exocitose/fisiologia , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Neuroblastoma/tratamento farmacológico , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Doxorrubicina/administração & dosagem , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Exocitose/efeitos dos fármacos , Inibidores de Histona Desacetilases/administração & dosagem , Humanos , Lisossomos/metabolismo , Neuroblastoma/metabolismo , Neuroblastoma/patologiaRESUMO
Epigenetic modifiers of the histone deacetylase (HDAC) family contribute to autoimmunity, cancer, HIV infection, inflammation, and neurodegeneration. Hence, histone deacetylase inhibitors (HDACi), which alter protein acetylation, gene expression patterns, and cell fate decisions, represent promising new drugs for the therapy of these diseases. Whereas pan-HDACi inhibit all 11 Zn2+-dependent histone deacetylases (HDACs) and cause a broad spectrum of side effects, specific inhibitors of histone deacetylase 6 (HDAC6i) are supposed to have less side effects. We present the synthesis and biological evaluation of Marbostats, novel HDAC6i that contain the hydroxamic acid moiety linked to tetrahydro-ß-carboline derivatives. Our lead compound Marbostat-100 is a more potent and more selective HDAC6i than previously established well-characterized compounds in vitro as well as in cells. Moreover, Marbostat-100 is well tolerated by mice and effective against collagen type II induced arthritis. Thus, Marbostat-100 represents a most selective known HDAC6i and the possibility for clinical evaluation of a HDAC isoform-specific drug.