RESUMO
DNA methylation is an epigenetic modification of the mammalian genome that occurs predominantly at cytosine residues of the CpG dinucleotide. Following formaldehyde activation, pixantrone alkylates DNA and particularly favours the CpG motif. Aberrations in CpG methylation patterns are a feature of most cancer types, a characteristic that may determine their susceptibility to specific drug treatments. Given their common target, DNA methylation may modulate the DNA damage induced by formaldehyde-activated pixantrone. In vitro transcription, mass spectrometry and oligonucleotide band shift assays were utilized to establish that pixantrone-DNA adduct formation was consistently enhanced 2-5-fold at discrete methylated CpG doublets. The methylation-mediated enhancement was exquisitely sensitive to the position of the methyl substituent since methylation at neighboring cytosine residues failed to confer an increase in pixantrone-DNA alkylation. Covalent modification of DNA by formaldehyde-activated doxorubicin, but not cisplatin, was augmented by neighbouring CpG methylation, indicating that modulation of binding by CpG methylation is not a general feature of all alkylators. HCT116 colon cancer cells vastly deficient in CpG methylation were 12- and 10-fold more resistant to pixantrone and doxorubicin relative to the wild-type line, suggesting that these drugs may selectively recognize the aberrant CpG methylation profiles characteristic of most tumour types.
Assuntos
Antibióticos Antineoplásicos/toxicidade , Ilhas de CpG , Dano ao DNA , Metilação de DNA , Doxorrubicina/toxicidade , Isoquinolinas/toxicidade , 5-Metilcitosina/análogos & derivados , Linhagem Celular Tumoral , Adutos de DNA/análise , DNA-Citosina Metilases , Formaldeído/química , Humanos , Espectrometria de MassasRESUMO
Multinuclear platinum complexes are characterized by a peculiar DNA binding mode and higher cytotoxic potency than the mononuclear complexes, and efficacy against a wide range of preclinical tumor models. To reduce the high irreversible plasma protein binding and improve the chemical and metabolic drug stability, novel bis-platinum complexes were designed starting from the parent compound CT-3610. The novel second-generation bis-platinum complexes utilize alkylcarboxylate as leaving groups to improve their pharmacokinetic and pharmacodynamic profiles, thus overcoming the limitations of the previously developed multinuclear compounds. The selected compounds [CT-47518 and CT-47463, respectively (bis-capronate) platinum and (bis-butyrate) platinum], have similar in vitro degradation kinetics in human and murine plasma and, above all, an increased stability when compared to CT-3610, particularly in human plasma. In addition, both compounds exhibited a marked cytotoxic potency as compared with cisplatin and oxaliplatin. Interestingly, they were capable of overcoming resistance mediated by DNA mismatch repair defects in different cellular models. The complexes showed marked antitumor efficacy in Pt-refractory tumor xenografts, with remarkable activity in terms of tumor growth inhibition and tumor growth delay. The improved stability profile in human plasma compared to early bis- and triplatinum complexes together with the marked activity in cellular systems as well as in in vivo models, make CT-47518 and CT-47463 attractive candidates for further development.
Assuntos
Antineoplásicos/farmacologia , Compostos Organoplatínicos/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Cisplatino/farmacologia , Adutos de DNA/metabolismo , Reparo de Erro de Pareamento de DNA , Desenho de Fármacos , Resistencia a Medicamentos Antineoplásicos , Estabilidade de Medicamentos , Feminino , Humanos , Camundongos , Camundongos Nus , Compostos Organoplatínicos/química , Compostos Organoplatínicos/farmacocinética , Oxaliplatina , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The topoisomerase II poison mitoxantrone is important in the clinical management of human malignancies. Pixantrone, a novel aza-anthracenedione developed to improve the therapeutic profile of mitoxantrone, can efficiently alkylate DNA after formaldehyde activation. In vitro transcriptional analysis has now established that formaldehyde-activated pixantrone generates covalent adducts selectively at discrete CpG or CpA dinucleotides, suggesting that the activated complex binds to guanine or cytosine (or both) bases. The stability of pixantrone adduct-induced transcriptional blockages varied considerably, reflecting a mixture of distinct pixantrone adduct types that may include relatively labile monoadducts and more stable interstrand cross-links. 6,9-Bis-[[2-(dimethylamino)ethyl]amino]benzo[g]isoquinoline-5,10-dione (BBR 2378), the dimethyl N-substituted analog of pixantrone, could not form adducts, suggesting that pixantrone alkylates DNA through the primary amino functions located in each side chain of the drug. Pixantrone generated DNA adducts only when guanine was present in substrates and exhibited a lack of adduct formation with inosine-containing polynucleotides, confirming that the N2 amino group of guanine is the site for covalent attachment of the drug. Mass spectrometric analysis of oligonucleotide-drug complexes confirmed that formation of covalent pixantrone-DNA adducts is mediated by a single methylene linkage provided by formaldehyde and that this occurs only with guanine-containing double stranded oligonucleotide substrates. CpG methylation, an epigenetic modification of the mammalian genome, significantly enhanced the generation of pixantrone-DNA adducts within a methylated DNA substrate, indicating that the methylated dinucleotide may be a favored target in a cellular environment.
Assuntos
Nucleotídeos de Adenina/metabolismo , Alquilantes/metabolismo , Antineoplásicos/metabolismo , Adutos de DNA/metabolismo , Formaldeído/farmacologia , Isoquinolinas/metabolismo , Nucleotídeos de Adenina/química , Alquilantes/química , Antineoplásicos/química , Sequência de Bases , Ilhas de CpG , Metilação de DNA , Isoquinolinas/química , Estrutura MolecularRESUMO
The ubiquitin-proteasome pathway plays a central role in regulation of the production and destruction of cellular proteins. These pathways mediate proliferation and cell survival, particularly in malignant cells. The successful development of the 20S human proteasome inhibitor bortezomib for the treatment of relapsed and refractory multiple myeloma has established this targeted intervention as an effective therapeutic strategy. Herein, the potent, selective, and orally bioavailable threonine-derived 20S human proteasome inhibitor that has been advanced to preclinical development, [(1R)-1-[[(2 S,3 R)-3-hydroxy-2-[(6-phenylpyridine-2-carbonyl)amino]-1-oxobutyl]amino]-3-methylbutyl]boronic acid 20 (CEP-18770), is disclosed.
Assuntos
Antineoplásicos/síntese química , Inibidores de Proteassoma , Administração Oral , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Camundongos , Transplante de Neoplasias , Complexo de Endopeptidases do Proteassoma/química , Ratos , Ratos Sprague-Dawley , Estereoisomerismo , Relação Estrutura-Atividade , Transplante HeterólogoRESUMO
Lysophosphatidic acid, the substrate for lysophosphatidic acid acyltransferase beta (LPAAT-beta), is a well-studied autocrine/paracrine signaling molecule that is secreted by ovarian cancer cells and is found at elevated levels in the blood and ascites fluid of women with ovarian cancer. LPAAT-beta converts lysophosphatidic acid to phosphatidic acid, which functions as a cofactor in Akt/mTOR and Ras/Raf/Erk pathways. We report that elevated expression of LPAAT-beta was associated with reduced survival in ovarian cancer and earlier progression of disease in ovarian and endometrial cancer. Inhibition of LPAAT-beta using small interfering RNA or selective inhibitors, CT32521 and CT32228, two small-molecule noncompetitive antagonists representing two different classes of chemical structures, induces apoptosis in human ovarian and endometrial cancer cell lines in vitro at pharmacologically tenable nanomolar concentrations. Inhibition of LPAAT-beta also enhanced the survival of mice bearing ovarian tumor xenografts. Cytotoxicity was modulated by diacylglycerol effectors including protein kinase C and CalDAG-GEF1. LPAAT-beta was localized to the endoplasmic reticulum and overexpression was associated with redistribution of protein kinase C-alpha. These findings identify LPAAT-beta as a potential prognostic and therapeutic target in ovarian and endometrial cancer.
Assuntos
Aciltransferases/biossíntese , Biomarcadores Tumorais/biossíntese , Neoplasias dos Genitais Femininos/enzimologia , Aciltransferases/antagonistas & inibidores , Aciltransferases/genética , Animais , Linhagem Celular Tumoral , Inibidores Enzimáticos/farmacologia , Feminino , Neoplasias dos Genitais Femininos/tratamento farmacológico , Neoplasias dos Genitais Femininos/genética , Humanos , Hidrocarbonetos Halogenados/farmacologia , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Prognóstico , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Interferente Pequeno/genética , Transdução de Sinais , Serina-Treonina Quinases TOR , Triazinas/farmacologia , Regulação para Cima , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
NAMI-A is a ruthenium complex endowed with a selective effect on lung metastases of solid metastasizing tumors. The aim of this study is to provide evidence that NAMI-A's effect is based on the selective sensitivity of the metastasis cell, as compared with other tumor cells, and to show that lungs represent a privileged site for the antimetastatic effects. The transplantation of Lewis lung carcinoma cells, harvested from the primary tumor of mice treated with 35 mg/kg/day NAMI-A for six consecutive days, a dose active on metastases, shows no change in primary tumor take and growth but a significant reduction in formation of spontaneous lung metastases. Transmission electron microscopy examination of lungs and kidney shows NAMI-A to selectively bind collagen of the lung extracellular matrix and also type IV collagen of the basement membrane of kidney glomeruli. The half lifetime of NAMI-A elimination from the lungs is longer than for liver, kidney, and primary tumor. NAMI-A bound to collagen is active on tumor cells as shown in vitro by an invasion test, using a modified Boyden chamber and Matrigel, and it inhibits the matrix metallo-proteinases MMP-2 and MMP-9 at micromolar concentrations, as shown in vitro by a zimography test. These data show NAMI-A to significantly affect tumor cells with metastatic ability. Binding to collagen allows NAMI-A to exert its selective activity on metastatic cells during dissemination and particularly in the lungs. These data also stress the wide spectrum of daily doses and treatment schedules at which NAMI-A is active against metastases.
Assuntos
Antineoplásicos/farmacologia , Carcinoma Pulmonar de Lewis/prevenção & controle , Colágeno Tipo IV/metabolismo , Dimetil Sulfóxido/análogos & derivados , Dimetil Sulfóxido/metabolismo , Dimetil Sulfóxido/farmacologia , Neoplasias Pulmonares/prevenção & controle , Neoplasias Mamárias Experimentais/prevenção & controle , Compostos Organometálicos/metabolismo , Compostos Organometálicos/farmacologia , Adenocarcinoma/prevenção & controle , Adenocarcinoma/secundário , Animais , Carcinoma Pulmonar de Lewis/secundário , Adesão Celular , Divisão Celular/efeitos dos fármacos , Colágeno , Combinação de Medicamentos , Feminino , Humanos , Rim/ultraestrutura , Laminina , Pulmão/ultraestrutura , Neoplasias Pulmonares/patologia , Neoplasias Mamárias Experimentais/secundário , Inibidores de Metaloproteinases de Matriz , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Invasividade Neoplásica/prevenção & controle , Proteoglicanas , Rutênio/metabolismo , Compostos de Rutênio , Células Tumorais CultivadasRESUMO
Pixantrone (BBR2778) (PIX) and mitoxantrone share the same mechanism of action because both drugs act as DNA intercalants and inhibitors of topoisomerase II. PIX is an interesting candidate immunosuppressant for the treatment of autoimmune diseases because of its reduced cardiotoxicity compared with mitoxantrone. The clinical response to conventional immunosuppressive treatments is poor in some patients affected by myasthenia gravis (MG), and new but well-tolerated drugs are needed for treatment-resistant MG. PIX was tested in vitro on rat T cell lines specific for the immunodominant peptide 97-116 derived from rat acetylcholine receptor (AChR), and showed strong antiproliferative activity in the nanomolar range. We demonstrate in this study that PIX administration reduced the severity of experimental autoimmune MG in Lewis rats. Biological and immunological analysis confirmed the effect of PIX, compared with vehicle-treated as well as mitoxantrone-treated experimental autoimmune MG rats. Anti-rat AChR Abs were significantly reduced in PIX-treated rats, and AChR content in muscles were found increased. Torpedo AChR-induced T cell proliferation tests were found reduced in both in vitro and ex vivo experiments. The effectiveness and the reduced cardiotoxicity make PIX a promising immunosuppressant agent suitable for clinical investigation in MG, although additional experiments are needed to confirm its safety profile in prolonged treatments.
Assuntos
Imunossupressores/administração & dosagem , Isoquinolinas/administração & dosagem , Miastenia Gravis Autoimune Experimental/prevenção & controle , Índice de Gravidade de Doença , Sequência de Aminoácidos , Animais , Proliferação de Células/efeitos dos fármacos , Feminino , Epitopos Imunodominantes/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Ativação Linfocitária/imunologia , Dados de Sequência Molecular , Miastenia Gravis Autoimune Experimental/tratamento farmacológico , Miastenia Gravis Autoimune Experimental/imunologia , Antagonistas Nicotínicos/administração & dosagem , Fragmentos de Peptídeos/antagonistas & inibidores , Ratos , Ratos Endogâmicos Lew , Receptores Nicotínicos/metabolismo , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo , TorpedoRESUMO
Modulating protein ubiquitination via proteasome inhibition represents a promising target for cancer therapy, because of the higher sensitivity of cancer cells to the cytotoxic effects of proteasome inhibition. Here we show that CEP-18770 is a novel orally-active inhibitor of the chymotrypsin-like activity of the proteasome that down-modulates the nuclear factor-kappaB (NF-kappaB) activity and the expression of several NF-kappaB downstream effectors. CEP-18770 induces apoptotic cell death in multiple myeloma (MM) cell lines and in primary purified CD138-positive explant cultures from untreated and bortezomib-treated MM patients. In vitro, CEP-18770 has a strong antiangiogenic activity and potently represses RANKL-induced osteoclastogenesis. Importantly, CEP-18770 exhibits a favorable cytotoxicity profile toward normal human epithelial cells, bone marrow progenitors, and bone marrow-derived stromal cells. Intravenous and oral administration of CEP-18770 resulted in a more sustained pharmacodynamic inhibition of proteasome activity in tumors relative to normal tissues, complete tumor regression of MM xenografts and improved overall median survival in a systemic model of human MM. Collectively, these findings provide evidence for the utility of CEP-18770 as a novel orally active proteasome inhibitor with a favorable tumor selectivity profile for the treatment of MM and other malignancies responsive to proteasome inhibition.
Assuntos
Antineoplásicos/farmacologia , Ácidos Borônicos/farmacologia , Inibidores Enzimáticos/farmacologia , Neoplasias/tratamento farmacológico , Inibidores de Proteassoma , Pirazinas/farmacologia , Treonina/análogos & derivados , Administração Oral , Animais , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Ácidos Borônicos/administração & dosagem , Ácidos Borônicos/química , Ácidos Borônicos/uso terapêutico , Bortezomib , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Inibidores Enzimáticos/uso terapêutico , Humanos , Fator Estimulador de Colônias de Macrófagos/farmacologia , Camundongos , Camundongos Nus , Mieloma Múltiplo/patologia , NF-kappa B/antagonistas & inibidores , Neoplasias/patologia , Osteogênese/efeitos dos fármacos , Pirazinas/administração & dosagem , Pirazinas/uso terapêutico , Ligante RANK/farmacologia , Treonina/administração & dosagem , Treonina/química , Treonina/farmacologia , Treonina/uso terapêutico , Resultado do Tratamento , Ubiquitina/antagonistas & inibidores , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
A recent approach in anticancer chemotherapy envisages telomerase as a potentially useful target. An attractive strategy deals with the development of compounds able to stabilize telomeric DNA in the G-quadruplex folded structure and, among them, a prominent position is found in the perylenes. With the aim to further investigate the role of drug structure, in view of possible pharmaceutical applications, we synthesized a series of compounds related to PIPER, a well-known perylene-based telomerase inhibitor. We modified the number of condensed aromatic rings and introduced different side chains to modulate drug protonation state and extent of self-aggregation. Effective telomerase inhibition was induced by heptacyclic analogues only, some showing a remarkably wide selectivity index with reference to inhibition of Taq polymerase. G-quadruplex stabilization was monitored by circular dichroism and melting experiments. Cell cytotoxicity measurements indicated a poor short-term cell killing ability for the best G-quartet binders. Besides the presence of a planar seven-condensed ring system, the introduction of a cyclic amine in the side chains critically affects the selectivity window.
Assuntos
Antineoplásicos/farmacologia , DNA/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Perileno/análogos & derivados , Perileno/farmacologia , Telomerase/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dicroísmo Circular , DNA/química , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Estrutura Molecular , Perileno/síntese química , Sensibilidade e Especificidade , Estereoisomerismo , Relação Estrutura-Atividade , Taq Polimerase/antagonistas & inibidoresRESUMO
Paclitaxel is a widely used chemotherapeutic agent; however, its therapeutic index is limited by low tumor exposure and high systemic exposure. Paclitaxel poliglumex (PPX) is macromolecular drug conjugate that links paclitaxel with a biodegradable polymer, poly-L-glutamic acid. PPX enhances tumor exposure by taking advantage of the hyperpermeable vasculature and suppressed lymphatic clearance characteristic of tumor tissue. The release of paclitaxel from the polymeric backbone is, at least in part, dependent on the metabolism of PPX by the lysosomal protease cathepsin B, which is upregulated in many tumor types. Retrospective analysis of clinical data from two phase III trials in advanced lung cancer suggests that PPX activity may be modulated by estradiol: a trend toward improved survival in the PPX arm compared with the control arm was observed in female, but not in male patients. Estrogens are known to induce cathepsin B activity; cathepsin B-mediated proteolysis is a key enzymatic processing step in PPX metabolism. The association between estrogens and PPX activity is being further explored in ongoing preclinical studies. An additional phase III trial will enroll women with advanced NSCLC to prospectively evaluate the efficacy of PPX in relation to pre- and post-menopausal estrogen levels.
Assuntos
Apoptose/efeitos dos fármacos , Portadores de Fármacos/química , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Paclitaxel/administração & dosagem , Ácido Poliglutâmico/química , Tubulina (Proteína)/metabolismo , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Estradiol/metabolismo , Humanos , Substâncias Macromoleculares/químicaRESUMO
Ro 41-4439, a phenyl-pyridine-2-carboxylic acid derivative, was identified by a cell-based screening approach that exploits the differences between normal and cancer cells in their sensitivity to cytotoxic agents. This compound showed low micromolar antiproliferative activity and cytotoxicity against a broad panel of human cancer cell lines in vitro, and over 10-fold selectivity to cancer cells when tested in parallel with a panel of proliferating normal human cells. Cytotoxicity of Ro 41-4439 is due to arrest of cell cycle progression in mitosis followed by induction of apoptosis. Four-week treatment of nude mice bearing established mammary tumor xenografts (MDA-MB-435) with well-tolerated doses of the compound showed 73% inhibition of tumor growth. Limited exploration of structure-activity relationships involving side chain length, and aryl and pyridine rings allowed for the identification of more potent analogs.