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1.
BMC Cancer ; 22(1): 1107, 2022 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-36309653

RESUMO

BACKGROUND: AZD0156 is an oral inhibitor of ATM, a serine threonine kinase that plays a key role in DNA damage response (DDR) associated with double-strand breaks. Topoisomerase-I inhibitor irinotecan is used clinically to treat colorectal cancer (CRC), often in combination with 5-fluorouracil (5FU). AZD0156 in combination with irinotecan and 5FU was evaluated in preclinical models of CRC to determine whether low doses of AZD0156 enhance the cytotoxicity of irinotecan in chemotherapy regimens used in the clinic. METHODS: Anti-proliferative effects of single-agent AZD0156, the active metabolite of irinotecan (SN38), and combination therapy were evaluated in 12 CRC cell lines. Additional assessment with clonogenic assay, cell cycle analysis, and immunoblotting were performed in 4 selected cell lines. Four colorectal cancer patient derived xenograft (PDX) models were treated with AZD0156, irinotecan, or 5FU alone and in combination for assessment of tumor growth inhibition (TGI). Immunofluorescence was performed on tumor tissues. The DDR mutation profile was compared across in vitro and in vivo models. RESULTS: Enhanced effects on cellular proliferation and regrowth were observed with the combination of AZD0156 and SN38 in select models. In cell cycle analysis of these models, increased G2/M arrest was observed with combination treatment over either single agent. Immunoblotting results suggest an increase in DDR associated with irinotecan therapy, with a reduced effect noted when combined with AZD0156, which is more pronounced in some models. Increased TGI was observed with the combination of AZD0156 and irinotecan as compared to single-agent therapy in some PDX models. The DDR mutation profile was variable across models. CONCLUSIONS: AZD0156 and irinotecan provide a rational and active combination in preclinical colorectal cancer models. Variability across in vivo and in vitro results may be related to the variable DDR mutation profiles of the models evaluated. Further understanding of the implications of individual DDR mutation profiles may help better identify patients more likely to benefit from treatment with the combination of AZD0156 and irinotecan in the clinical setting.


Assuntos
Neoplasias Colorretais , Fluoruracila , Humanos , Irinotecano/uso terapêutico , Fluoruracila/farmacologia , Fluoruracila/uso terapêutico , Apoptose , Linhagem Celular Tumoral , Pontos de Checagem da Fase G2 do Ciclo Celular , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Camptotecina , Proteínas Mutadas de Ataxia Telangiectasia/genética
2.
Br J Cancer ; 123(9): 1424-1436, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32741974

RESUMO

BACKGROUND: Personalised medicine strategies may improve outcomes in pancreatic ductal adenocarcinoma (PDAC), but validation of predictive biomarkers is required. Having developed a clinical trial to assess the ATR inhibitor, AZD6738, in combination with gemcitabine (ATRi/gem), we investigated ATM loss as a predictive biomarker of response to ATRi/gem in PDAC. METHODS: Through kinase inhibition, siRNA depletion and CRISPR knockout of ATM, we assessed how ATM targeting affected the sensitivity of PDAC cells to ATRi/gem. Using flow cytometry, immunofluorescence and immunoblotting, we investigated how ATRi/gem synergise in ATM-proficient and ATM-deficient cells, before assessing the impact of ATM loss on ATRi/gem sensitivity in vivo. RESULTS: Complete loss of ATM function (through pharmacological inhibition or CRISPR knockout), but not siRNA depletion, sensitised to ATRi/gem. In ATM-deficient cells, ATRi/gem-induced replication catastrophe was augmented, while phospho-Chk2-T68 and phospho-KAP1-S824 persisted via DNA-PK activity. ATRi/gem caused growth delay in ATM-WT xenografts in NSG mice and induced regression in ATM-KO xenografts. CONCLUSIONS: ATM loss augments replication catastrophe-mediated cell death induced by ATRi/gem and may predict clinical responsiveness to this combination. ATM status should be carefully assessed in tumours from patients with PDAC, since distinction between ATM-low and ATM-null could be critical in maximising the success of clinical trials using ATM expression as a predictive biomarker.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Carcinoma Ductal Pancreático/tratamento farmacológico , Desoxicitidina/análogos & derivados , Neoplasias Pancreáticas/tratamento farmacológico , Piridinas/farmacologia , Pirimidinas/farmacologia , Quinolinas/farmacologia , Sulfóxidos/farmacologia , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/fisiologia , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desoxicitidina/farmacologia , Desoxicitidina/uso terapêutico , Sinergismo Farmacológico , Feminino , Técnicas de Inativação de Genes , Humanos , Indóis , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Morfolinas , Neoplasias Pancreáticas/patologia , Piridinas/administração & dosagem , Pirimidinas/administração & dosagem , Quinolinas/administração & dosagem , RNA Interferente Pequeno/farmacologia , Sulfonamidas , Sulfóxidos/administração & dosagem , Ensaios Antitumorais Modelo de Xenoenxerto , Gencitabina
3.
Br J Cancer ; 119(10): 1233-1243, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30385821

RESUMO

BACKGROUND: AZD0156 and AZD6738 are potent and selective inhibitors of ataxia-telangiectasia-kinase (ATM) and ataxia-telangiectasia-mutated and Rad3-related (ATR), respectively, important sensors/signallers of DNA damage. METHODS: We used multiplexed targeted-mass-spectrometry to select pRAD50(Ser635) as a pharmacodynamic biomarker for AZD0156-mediated ATM inhibition from a panel of 45 peptides, then developed and tested a clinically applicable immunohistochemistry assay for pRAD50(Ser635) detection in FFPE tissue. RESULTS: We found moderate pRAD50 baseline levels across cancer indications. pRAD50 was detectable in 100% gastric cancers (n = 23), 99% colorectal cancers (n = 102), 95% triple-negative-breast cancers (TNBC) (n = 40) and 87.5% glioblastoma-multiformes (n = 16). We demonstrated AZD0156 target inhibition in TNBC patient-derived xenograft models; where AZD0156 monotherapy or post olaparib treatment, resulted in a 34-72% reduction in pRAD50. Similar inhibition of pRAD50 (68%) was observed following ATM inhibitor treatment post irinotecan in a colorectal cancer xenograft model. ATR inhibition, using AZD6738, increased pRAD50 in the ATM-proficient models whilst in ATM-deficient models the opposite was observed, suggesting pRAD50 pharmacodynamics post ATR inhibition may be ATM-dependent and could be useful to determine ATM functionality in patients treated with ATR inhibitors. CONCLUSION: Together these data support clinical utilisation of pRAD50 as a biomarker of AZD0156 and AZD6738 pharmacology to elucidate clinical pharmacokinetic/pharmacodynamic relationships, thereby informing recommended Phase 2 dose/schedule.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Espectrometria de Massas/métodos , Animais , Antineoplásicos/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Biomarcadores/metabolismo , Linhagem Celular , Dano ao DNA , Humanos , Imuno-Histoquímica , Indóis , Irinotecano/farmacologia , Camundongos , Camundongos Nus , Morfolinas , Ftalazinas/farmacologia , Piperazinas/farmacologia , Piridinas/farmacologia , Piridinas/uso terapêutico , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Quinolinas/farmacologia , Quinolinas/uso terapêutico , Transdução de Sinais , Sulfonamidas , Sulfóxidos/farmacologia , Sulfóxidos/uso terapêutico , Neoplasias de Mama Triplo Negativas , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Am J Respir Crit Care Med ; 185(1): 34-43, 2012 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-21997333

RESUMO

RATIONALE: Inflammation and oxidative stress are linked to the deleterious effects of cigarette smoke in producing chronic obstructive pulmonary disease (COPD). Myeloperoxidase (MPO), a neutrophil and macrophage product, is important in bacterial killing, but also drives inflammatory reactions and tissue oxidation. OBJECTIVES: To determine the role of MPO in COPD. METHODS: We treated guinea pigs with a 2-thioxanthine MPO inhibitor, AZ1, in a 6-month cigarette smoke exposure model, with one group receiving compound from Smoking Day 1 and another group treated after 3 months of smoke exposure. RESULTS: At 6 months both treatments abolished smoke-induced increases in lavage inflammatory cells, largely ameliorated physiological changes, and prevented or stopped progression of morphologic emphysema and small airway remodeling. Cigarette smoke caused a marked increase in immunohistochemical staining for the myeloperoxidase-generated protein oxidation marker dityrosine, and this effect was considerably decreased with both treatment arms. Serum 8-isoprostane, another marker of oxidative stress, showed similar trends. Both treatments also prevented muscularization of the small intrapulmonary arteries, but only partially ameliorated smoke-induced pulmonary hypertension. Acutely, AZ1 prevented smoke-induced increases in expression of cytokine mediators and nuclear factor-κB binding. CONCLUSIONS: We conclude that an MPO inhibitor is able to stop progression of emphysema and small airway remodeling and to partially protect against pulmonary hypertension, even when treatment starts relatively late in the course of long-term smoke exposure, suggesting that inhibition of MPO may be a novel and useful therapeutic treatment for COPD. Protection appears to relate to inhibition of oxidative damage and down-regulation of the smoke-induced inflammatory response.


Assuntos
Inibidores Enzimáticos/farmacologia , Peroxidase/antagonistas & inibidores , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Doença Pulmonar Obstrutiva Crônica/metabolismo , Purinas/uso terapêutico , Fumar/efeitos adversos , Tionas/uso terapêutico , Remodelação das Vias Aéreas/efeitos dos fármacos , Animais , Dinoprosta/análogos & derivados , Dinoprosta/sangue , Modelos Animais de Doenças , Progressão da Doença , Feminino , Cobaias , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/prevenção & controle , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/prevenção & controle , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Peroxidase/metabolismo , Doença Pulmonar Obstrutiva Crônica/etiologia , Tioxantenos/antagonistas & inibidores , Tioxantenos/metabolismo , Tirosina/análogos & derivados , Tirosina/efeitos dos fármacos
5.
Cancers (Basel) ; 15(16)2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37627223

RESUMO

Ataxia-telangiectasia mutated gene (ATM) is a key component of the DNA damage response (DDR) and double-strand break repair pathway. The functional loss of ATM (ATM deficiency) is hypothesised to enhance sensitivity to DDR inhibitors (DDRi). Whole-exome sequencing (WES), immunohistochemistry (IHC), and Western blotting (WB) were used to characterise the baseline ATM status across a panel of ATM mutated patient-derived xenograft (PDX) models from a range of tumour types. Antitumour efficacy was assessed with poly(ADP-ribose)polymerase (PARP, olaparib), ataxia- telangiectasia and rad3-related protein (ATR, AZD6738), and DNA-dependent protein kinase (DNA-PK, AZD7648) inhibitors as a monotherapy or in combination to associate responses with ATM status. Biallelic truncation/frameshift ATM mutations were linked to ATM protein loss while monoallelic or missense mutations, including the clinically relevant recurrent R3008H mutation, did not confer ATM protein loss by IHC. DDRi agents showed a mixed response across the PDX's but with a general trend toward greater activity, particularly in combination in models with biallelic ATM mutation and protein loss. A PDX with an ATM splice-site mutation, 2127T > C, with a high relative baseline ATM expression and KAP1 phosphorylation responded to all DDRi treatments. These data highlight the heterogeneity and complexity in describing targetable ATM-deficiencies and the fact that current patient selection biomarker methods remain imperfect; although, complete ATM loss was best able to enrich for DDRi sensitivity.

6.
Nat Commun ; 14(1): 4761, 2023 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-37580318

RESUMO

Genome editing, specifically CRISPR/Cas9 technology, has revolutionized biomedical research and offers potential cures for genetic diseases. Despite rapid progress, low efficiency of targeted DNA integration and generation of unintended mutations represent major limitations for genome editing applications caused by the interplay with DNA double-strand break repair pathways. To address this, we conduct a large-scale compound library screen to identify targets for enhancing targeted genome insertions. Our study reveals DNA-dependent protein kinase (DNA-PK) as the most effective target to improve CRISPR/Cas9-mediated insertions, confirming previous findings. We extensively characterize AZD7648, a selective DNA-PK inhibitor, and find it to significantly enhance precise gene editing. We further improve integration efficiency and precision by inhibiting DNA polymerase theta (PolÏ´). The combined treatment, named 2iHDR, boosts templated insertions to 80% efficiency with minimal unintended insertions and deletions. Notably, 2iHDR also reduces off-target effects of Cas9, greatly enhancing the fidelity and performance of CRISPR/Cas9 gene editing.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Sistemas CRISPR-Cas/genética , Proteínas Quinases/genética , Reparo do DNA/genética , DNA/genética
7.
Mol Cancer Ther ; 21(4): 555-567, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35149547

RESUMO

Ovarian cancer is the deadliest gynecologic cancer, with a 5-year survival rate of 30%, when the disease has spread throughout the peritoneal cavity. We investigated the efficacy to delay disease progression by the DNA-dependent protein kinase (DNA-PK) inhibitor AZD7648, administered in combination with two of the therapeutic options for patient management: either pegylated liposomal doxorubicin (PLD) or the PARP inhibitor olaparib. Patient-derived ovarian cancer xenografts (OC-PDX) were transplanted subcutaneously to evaluate the effect of treatment on tumor growth, or orthotopically in the peritoneal cavity to evaluate the effect on metastatic spread. AZD7648 was administered orally in combination with PLD (dosed intravenously) or with olaparib (orally). To prove the inhibition of DNA-PK in the tumors, we measured pDNA-PKcs, pRPA32, and γH2AX, biomarkers of DNA-PK activity. AZD7648 enhanced the therapeutic efficacy of PLD in all the OC-PDXs tested, regardless of their BRCA status or sensitivity to cisplatin or PLD. The treatment caused disease stabilization, which persisted despite therapy discontinuation for tumors growing subcutaneously, and significantly impaired the abdominal metastatic dissemination, prolonging the lifespan of mice implanted orthotopically. AZD7648 potentiated the efficacy of olaparib in BRCA-deficient OC-PDXs but did not sensitize BRCA-proficient OC-PDXs to olaparib, despite an equivalent inhibition of DNA-PK, suggesting the need of a preexisting olaparib activity to benefit from the addition of AZD7648. This work suggests that AZD7648, an inhibitor of DNA-PK, dosed in combination with PLD or olaparib is an exciting therapeutic option that could benefit patients with ovarian cancer and should be explored in clinical trials.


Assuntos
Neoplasias Ovarianas , Inibidores de Proteínas Quinases , Animais , Linhagem Celular Tumoral , DNA/uso terapêutico , Doxorrubicina/análogos & derivados , Feminino , Xenoenxertos , Humanos , Camundongos , Neoplasias Ovarianas/patologia , Ftalazinas , Piperazinas , Polietilenoglicóis , Inibidores de Proteínas Quinases/uso terapêutico , Purinas , Piranos , Triazóis
8.
ACS Med Chem Lett ; 13(8): 1295-1301, 2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-35978693

RESUMO

The DNA-PK complex is activated by double-strand DNA breaks and regulates the non-homologous end-joining repair pathway; thus, targeting DNA-PK by inhibiting the DNA-PK catalytic subunit (DNA-PKcs) is potentially a useful therapeutic approach for oncology. A previously reported series of neutral DNA-PKcs inhibitors were modified to incorporate a basic group, with the rationale that increasing the volume of distribution while maintaining good metabolic stability should increase the half-life. However, adding a basic group introduced hERG activity, and basic compounds with modest hERG activity (IC50 = 10-15 µM) prolonged QTc (time from the start of the Q wave to the end of the T wave, corrected by heart rate) in an anaesthetized guinea pig cardiovascular model. Further optimization was necessary, including modulation of pK a, to identify compound 18, which combines low hERG activity (IC50 = 75 µM) with excellent kinome selectivity and favorable pharmacokinetic properties.

9.
Clin Cancer Res ; 27(15): 4353-4366, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34011558

RESUMO

PURPOSE: Combining radiotherapy (RT) with DNA damage response inhibitors may lead to increased tumor cell death through radiosensitization. DNA-dependent protein kinase (DNA-PK) plays an important role in DNA double-strand break repair via the nonhomologous end joining (NHEJ) pathway. We hypothesized that in addition to a radiosensitizing effect from the combination of RT with AZD7648, a potent and specific inhibitor of DNA-PK, combination therapy may also lead to modulation of an anticancer immune response. EXPERIMENTAL DESIGN: AZD7648 and RT efficacy, as monotherapy and in combination, was investigated in fully immunocompetent mice in MC38, CT26, and B16-F10 models. Immunologic consequences were analyzed by gene expression and flow-cytometric analysis. RESULTS: AZD7648, when delivered in combination with RT, induced complete tumor regressions in a significant proportion of mice. The antitumor efficacy was dependent on the presence of CD8+ T cells but independent of NK cells. Analysis of the tumor microenvironment revealed a reduction in T-cell PD-1 expression, increased NK-cell granzyme B expression, and elevated type I IFN signaling in mice treated with the combination when compared with RT treatment alone. Blocking of the type I IFN receptor in vivo also demonstrated a critical role for type I IFN in tumor growth control following combined therapy. Finally, this combination was able to generate tumor antigen-specific immunologic memory capable of suppressing tumor growth following rechallenge. CONCLUSIONS: Blocking the NHEJ DNA repair pathway with AZD7648 in combination with RT leads to durable immune-mediated tumor control.


Assuntos
Linhagem Celular Tumoral/efeitos da radiação , Proteína Quinase Ativada por DNA/antagonistas & inibidores , Interferon Tipo I/efeitos dos fármacos , Neoplasias/radioterapia , Inibidores de Proteínas Quinases/farmacologia , Purinas/farmacologia , Piranos/farmacologia , Radiossensibilizantes/farmacologia , Triazóis/farmacologia , Animais , Camundongos
10.
Mol Cancer Ther ; 19(1): 13-25, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31534013

RESUMO

AZD0156 is a potent and selective, bioavailable inhibitor of ataxia-telangiectasia mutated (ATM) protein, a signaling kinase involved in the DNA damage response. We present preclinical data demonstrating abrogation of irradiation-induced ATM signaling by low doses of AZD0156, as measured by phosphorylation of ATM substrates. AZD0156 is a strong radiosensitizer in vitro, and using a lung xenograft model, we show that systemic delivery of AZD0156 enhances the tumor growth inhibitory effects of radiation treatment in vivo Because ATM deficiency contributes to PARP inhibitor sensitivity, preclinically, we evaluated the effect of combining AZD0156 with the PARP inhibitor olaparib. Using ATM isogenic FaDu cells, we demonstrate that AZD0156 impedes the repair of olaparib-induced DNA damage, resulting in elevated DNA double-strand break signaling, cell-cycle arrest, and apoptosis. Preclinically, AZD0156 potentiated the effects of olaparib across a panel of lung, gastric, and breast cancer cell lines in vitro, and improved the efficacy of olaparib in two patient-derived triple-negative breast cancer xenograft models. AZD0156 is currently being evaluated in phase I studies (NCT02588105).


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/uso terapêutico , Ftalazinas/uso terapêutico , Piperazinas/uso terapêutico , Piridinas/uso terapêutico , Quinolinas/uso terapêutico , Radiossensibilizantes/uso terapêutico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/radioterapia , Animais , Proteínas Mutadas de Ataxia Telangiectasia/farmacologia , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos , Camundongos Nus , Ftalazinas/farmacologia , Piperazinas/farmacologia , Piridinas/farmacologia , Quinolinas/farmacologia , Radiossensibilizantes/farmacologia , Neoplasias de Mama Triplo Negativas/patologia
11.
J Med Chem ; 63(7): 3461-3471, 2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-31851518

RESUMO

DNA-PK is a key component within the DNA damage response, as it is responsible for recognizing and repairing double-strand DNA breaks (DSBs) via non-homologous end joining. Historically it has been challenging to identify inhibitors of the DNA-PK catalytic subunit (DNA-PKcs) with good selectivity versus the structurally related PI3 (lipid) and PI3K-related protein kinases. We screened our corporate collection for DNA-PKcs inhibitors with good PI3 kinase selectivity, identifying compound 1. Optimization focused on further improving selectivity while improving physical and pharmacokinetic properties, notably co-optimization of permeability and metabolic stability, to identify compound 16 (AZD7648). Compound 16 had no significant off-target activity in the protein kinome and only weak activity versus PI3Kα/γ lipid kinases. Monotherapy activity in murine xenograft models was observed, and regressions were observed when combined with inducers of DSBs (doxorubicin or irradiation) or PARP inhibition (olaparib). These data support progression into clinical studies (NCT03907969).


Assuntos
Proteína Quinase Ativada por DNA/antagonistas & inibidores , Inibidores de Proteínas Quinases/uso terapêutico , Purinas/uso terapêutico , Piranos/uso terapêutico , Triazóis/uso terapêutico , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Classe Ib de Fosfatidilinositol 3-Quinase/metabolismo , Cães , Descoberta de Drogas , Humanos , Camundongos , Estrutura Molecular , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Purinas/síntese química , Purinas/farmacocinética , Piranos/síntese química , Piranos/farmacocinética , Ratos , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/antagonistas & inibidores , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/farmacocinética , Ensaios Antitumorais Modelo de Xenoenxerto
12.
Nat Commun ; 10(1): 5065, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31699977

RESUMO

DNA-dependent protein kinase (DNA-PK) is a critical player in the DNA damage response (DDR) and instrumental in the non-homologous end-joining pathway (NHEJ) used to detect and repair DNA double-strand breaks (DSBs). We demonstrate that the potent and highly selective DNA-PK inhibitor, AZD7648, is an efficient sensitizer of radiation- and doxorubicin-induced DNA damage, with combinations in xenograft and patient-derived xenograft (PDX) models inducing sustained regressions. Using ATM-deficient cells, we demonstrate that AZD7648, in combination with the PARP inhibitor olaparib, increases genomic instability, resulting in cell growth inhibition and apoptosis. AZD7648 enhanced olaparib efficacy across a range of doses and schedules in xenograft and PDX models, enabling sustained tumour regression and providing a clear rationale for its clinical investigation. Through its differentiated mechanism of action as an NHEJ inhibitor, AZD7648 complements the current armamentarium of DDR-targeted agents and has potential in combination with these agents to achieve deeper responses to current therapies.


Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Proteína Quinase Ativada por DNA/antagonistas & inibidores , Sinergismo Farmacológico , Inibidores de Proteínas Quinases/farmacologia , Purinas/farmacologia , Piranos/farmacologia , Tolerância a Radiação/efeitos dos fármacos , Triazóis/farmacologia , Células A549 , Animais , Antibióticos Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas , Linhagem Celular Tumoral , Doxorrubicina/análogos & derivados , Doxorrubicina/farmacologia , Instabilidade Genômica/efeitos dos fármacos , Humanos , Neoplasias Pulmonares , Camundongos , Ftalazinas/farmacologia , Piperazinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Polietilenoglicóis/farmacologia , Radioterapia , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Mol Cancer Ther ; 17(8): 1637-1647, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29769307

RESUMO

Inhibition of ataxia-telangiectasia mutated (ATM) during radiotherapy of glioblastoma multiforme (GBM) may improve tumor control by short-circuiting the response to radiation-induced DNA damage. A major impediment for clinical implementation is that current inhibitors have limited central nervous system (CNS) bioavailability; thus, the goal was to identify ATM inhibitors (ATMi) with improved CNS penetration. Drug screens and refinement of lead compounds identified AZ31 and AZ32. The compounds were then tested in vivo for efficacy and impact on tumor and healthy brain. Both AZ31 and AZ32 blocked the DNA damage response and radiosensitized GBM cells in vitro AZ32, with enhanced blood-brain barrier (BBB) penetration, was highly efficient in vivo as radiosensitizer in syngeneic and human, orthotopic mouse glioma model compared with AZ31. Furthermore, human glioma cell lines expressing mutant p53 or having checkpoint-defective mutations were particularly sensitive to ATMi radiosensitization. The mechanism for this p53 effect involves a propensity to undergo mitotic catastrophe relative to cells with wild-type p53. In vivo, apoptosis was >6-fold higher in tumor relative to healthy brain after exposure to AZ32 and low-dose radiation. AZ32 is the first ATMi with oral bioavailability shown to radiosensitize glioma and improve survival in orthotopic mouse models. These findings support the development of a clinical-grade, BBB-penetrating ATMi for the treatment of GBM. Importantly, because many GBMs have defective p53 signaling, the use of an ATMi concurrent with standard radiotherapy is expected to be cancer-specific, increase the therapeutic ratio, and maintain full therapeutic effect at lower radiation doses. Mol Cancer Ther; 17(8); 1637-47. ©2018 AACR.


Assuntos
Barreira Hematoencefálica/metabolismo , Glioma/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Radiossensibilizantes/uso terapêutico , Administração Oral , Animais , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Linhagem Celular Tumoral , Humanos , Camundongos , Camundongos Nus , Inibidores de Proteínas Quinases/farmacologia , Radiossensibilizantes/farmacologia
14.
Oncotarget ; 8(67): 110904-110913, 2017 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-29340025

RESUMO

Irinotecan, a standard of care therapy for CRC, elicits cytotoxic effects by generating double strand breaks resulting in DNA damage. The activation of the ATM pathway plays a fundamental role in regulating the cellular response and repair to DNA damage. The objective of this preclinical study was to determine whether ATM inhibition would enhance sensitivity to irinotecan treatment. Treatment effects of AZ31, irinotecan or AZ31 + irinotecan were investigated in CRC cell lines and CRC patient derived xenografts. Activation of ATM and downstream targets p-RAD50 and p-H2AX were evaluated by immunohistochemistry. Combinational effects were demonstrated in 4 out of 8 CRC explants. Interestingly, each of the combinational sensitive CRC PDX models were shown to be more resistant to irinotecan single agent therapy. Treatment with irinotecan significantly elevated the ATM pathway evident by an increase in the activation of H2AX and RAD50. Combinational therapy reduced the activation of H2AX and RAD50 when compared to irinotecan alone in the combination sensitive CRC098. AZ31 + irinotecan was effective at reducing tumor growth in tumors that exhibited resistance to irinotecan in our CRC PDX model. These findings support further investigation of this combinational therapy for the treatment of CRC patients.

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