RESUMO
The ATR-CHK1 pathway plays a fundamental role in the DNA damage response and is therefore an attractive target in cancer therapy. The antitumorous effect of ATR inhibitors is at least partly caused by synthetic lethality between ATR and various DNA repair genes. In previous studies, we have identified members of the B-family DNA polymerases as potential lethal partner for ATR, i.e. POLD1 and PRIM1. In this study, we validated and characterized the synthetic lethality between ATR and POLA1. First, we applied a model of ATR-deficient DLD-1 human colorectal cancer cells to confirm synthetic lethality by using chemical POLA1 inhibition. Analyzing cell cycle and apoptotic markers via FACS and Western blotting, we were able to show that apoptosis and S phase arrest contributed to the increased sensitivity of ATR-deficient cancer cells towards POLA1 inhibitors. Importantly, siRNA-mediated POLA1 depletion in ATR-deficient cells caused similar effects in regard to impaired cell viability and cumulation of apoptotic markers, thus excluding toxic effects of chemical POLA1 inhibition. Conversely, we demonstrated that siRNA-mediated POLA1 depletion sensitized several cancer cell lines towards chemical inhibition of ATR and its main effector kinase CHK1. In conclusion, the synthetic lethality between ATR/CHK1 and POLA1 might represent a novel and promising approach for individualized cancer therapy: First, alterations of POLA1 could serve as a screening parameter for increased sensitivity towards ATR and CHK1 inhibitors. Second, alterations in the ATR-CHK1 pathway might predict in increased sensitivity towards POLA1 inhibitors.
RESUMO
PURPOSE: First-line therapy options in advanced cholangiocarcinoma (CCA) are based on the ABC-02 trial regimen (gemcitabine/cisplatin [G/C]). The NIFE trial examined nanoliposomal irinotecan/fluorouracil/leucovorin (nal-IRI/FU/LV) as alternative first-line therapy in advanced CCA. METHODS: NIFE is a prospective, open-label, randomized, multicenter phase II study that aimed at detecting efficacy comparable with the standard treatment. Patients with advanced CCA were randomly assigned (1:1) to receive nal-IRI/FU/LV (arm A) or G/C (arm B). Stratification parameters were intrahepatic versus extrahepatic CCA, sex, and Eastern Cooperative Oncology Group (ECOG; 0/1). Arm A was designed as a Simon's optimal two-stage design and arm B served as a randomized control group. The primary goal was to exclude an inferior progression-free survival (PFS) at 4 months of only 40%, while assuming a rate of 60% on G/C population. RESULTS: Between 2018 and 2020, overall 91 patients were randomly assigned to receive nal-IRI/FU/LV (n = 49) or G/C (n = 42). The NIFE trial formally met its primary end point with a 4-month PFS rate of 51% in patients receiving nal-IRI/FU/LV. The median PFS was 6 months (2.4-9.6) in arm A and 6.9 months (2.5-7.9) in arm B. Median overall survival (OS) was 15.9 months (10.6-20.3) in arm A and 13.6 months (6.5-17.7) in arm B. The exploratory comparison of study arms suggested a numerical but statistically not significant advantage for nal-IRI/FU/LV (hazard ratio for PFS, 0.85 [95% CI, 0.53 to 1.38] and for OS, 0.94 [95% CI, 0.58 to 1.50]). Analysis for stratification parameters revealed no differences for sex and ECOG, but for tumor localization. The objective response rate was 24.5% with nal-IRI/FU/LV and 11.9% with G/C. No unexpected toxicities occurred. AEs related to nal-IRI/FU/LV were mainly GI and to G/C hematologic. CONCLUSION: Treatment of advanced CCA with nal-IRI/FU/LV demonstrated efficacy in first-line therapy without new safety findings and merits further validation.
RESUMO
Few data exist on health-related quality of life (QoL) in patients with metastatic pancreatic cancer (mPC) receiving first-line chemotherapy (Awad L ZE, Mesbah M Boston, MA. Applying survival data methodology to analyze quality of life data, in Mesbah M, Cole BF, Ting Lee M-L (eds): Statistical Methods for Quality of Life Studies: Design, Measurements and Analysis. Kluwer Academic Publishers 2002). The QOLIXANE study is a prospective, noninterventional, multicenter substudy of the Platform for Outcome, Quality of Life and Translational Research on Pancreatic Cancer (PARAGON) registry, which evaluated QoL in patients with mPC receiving first-line gemcitabine and nab-paclitaxel chemotherapy in real-life setting. QoL was prospectively measured via EORTC QLQ-C30 questionnaires at baseline and every month thereafter. Therapy and efficacy parameters were prospectively collected. Main objectives were the rate of patients without deterioration of Global Health Status/QoL (GHS/QoL) at 3 and 6 months. Six hundred patients were enrolled in 95 German study sites. Median progression-free survival was 5.9 months (95% confidence interval [CI], 5.2-6.3). Median overall survival (OS) was 8.9 months (95% CI, 7.9-10.2), while median time to deterioration of GHS/QoL was 4.7 months (95% CI, 4.0-5.6). With a baseline GHS/QoL score of 46 (SD, 22.8), baseline QoL of the patients was severely impaired, in most cases due to loss in role functioning and fatigue. In the Kaplan-Meier analysis, 61% and 41% of patients had maintained GHS/QoL after 3 and 6 months, respectively. However, in the QoL response analysis, 35% and 19% of patients had maintained (improved or stable) GHS/QoL after 3 and 6 months, respectively, while 14% and 9% had deteriorated GHS/QoL with the remaining patients being nonevaluable. In the Cox regression analysis, GHS/QoL scores strongly predicted survival with a hazard ratio of 0.86 (P < .0001). Patients with mPC have poor QoL at baseline that deteriorates within a median of 4.7 months. Treatment with gemcitabine and nab-paclitaxel is associated with maintained QoL in relevant proportions of patients. However, overall, results remain poor, reflecting the aggressive nature of the disease.
Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Qualidade de Vida , Adulto , Idoso , Idoso de 80 Anos ou mais , Albuminas/uso terapêutico , Desoxicitidina/análogos & derivados , Desoxicitidina/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Paclitaxel/uso terapêutico , Sistema de Registros , Resultado do Tratamento , GencitabinaRESUMO
Inhibition of the kinase ATR, a central regulator of the DNA damage response, eliminates subsets of cancer cells in certain tumors. As previously shown, this is at least partly attributable to synthetic lethal interactions between ATR and POLD1, the catalytic subunit of the polymerase δ. Various POLD1 variants have been found in colorectal cancer, but their significance as therapeutic targets for ATR pathway inhibition remains unknown. Using CRISPR/Cas9 in the colorectal cancer cell line DLD-1, which harbors four POLD1 variants, we established heterozygous POLD1-knockout clones with exclusive expression of distinct variants to determine the functional relevance of these variants individually by assessing their impact on ATR pathway activation, DNA replication, and cellular sensitivity to inhibition of ATR or its effector kinase CHK1. Of the four variants analyzed, only POLD1R689W affected POLD1 function, as demonstrated by compensatory ATR pathway activation and impaired DNA replication. Upon treatment with ATR or CHK1 inhibitors, POLD1R689W strongly decreased cell survival in vitro, which was attributable at least partly to S phase impairment and apoptosis. Similarly, treatment with the ATR inhibitor AZD6738 inhibited growth of murine xenograft tumors, harboring the POLD1R689W variant, in vivo. Our POLD1-knockout model thus complements algorithm-based models to predict the pathogenicity of tumor-specific variants of unknown significance and illustrates a novel and potentially clinically relevant therapeutic approach using ATR/CHK1 inhibitors in POLD1-deficient tumors.
Assuntos
Substituição de Aminoácidos , Neoplasias Colorretais/tratamento farmacológico , DNA Polimerase III/genética , Pirimidinas/administração & dosagem , Sulfóxidos/administração & dosagem , Animais , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quinase 1 do Ponto de Checagem/antagonistas & inibidores , Neoplasias Colorretais/genética , Replicação do DNA/efeitos dos fármacos , Técnicas de Inativação de Genes , Humanos , Indóis , Camundongos , Morfolinas , Pirimidinas/farmacologia , Sulfonamidas , Sulfóxidos/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The most frequent malignancy of the pancreas is the pancreatic ductal adenocarcinoma (PDAC). Despite many efforts PDAC has still a dismal prognosis. Biomarkers for early disease stage diagnosis as a prerequisite for a potentially curative treatment are still missing. Novel blood-based markers may help to overcome this limitation. Methods: Prior to surgery plasma levels of thrombospondin-2 (THBS2), which was recently published as a novel biomarker, and CA19-9 from 52 patients with histologically proven PDAC were determined, circulating cell-free (cfDNA) was quantified. 15 patients with side-branch IPMNs without worrisome features and 32 patients with chronic pancreatitis served for comparison. Logit (logistic regression) models were used to test the performance of single biomarkers and biomarker combinations. Results: CA19-9 and THBS2 alone showed comparable c-statistics of 0.80 and 0.73, respectively, improving to 0.87 when combining these two markers. The c-statistic was further increased to 0.94 when combining CA19-9 and THBS2 with cfDNA quantification. This marker combination performed best for all PDAC stages but also for PDACs grouped by stage. The greatest improvement over CA19-9 was seen in the group of stage I PDAC, from 0.69 to 0.90 for the three marker combination. Conclusion:These data establish the combination of CA19-9, THBS2 and cfDNA as a composite liquid biomarker for non-invasive diagnosis of early-stage PDAC.
Assuntos
Adenocarcinoma/diagnóstico , Biomarcadores Tumorais/sangue , Análise Química do Sangue/métodos , Carcinoma Ductal Pancreático/diagnóstico , Diagnóstico Diferencial , Testes Diagnósticos de Rotina/métodos , Diagnóstico Precoce , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos Glicosídicos Associados a Tumores/sangue , Ácidos Nucleicos Livres/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Trombospondinas/sangue , Adulto JovemRESUMO
Heterozygous germline BRCA2 mutations predispose to breast, ovarian, pancreatic and other types of cancer. The presence of a pathogenic mutation in patients or their family members warrants close surveillance or prophylactic surgery. Besides clearly pathogenic mutations, variants leading only to a single amino acid substitution are often identified. The influence of such variants on cancer risk is often unknown, making their presence a major clinical problem. When genetic methods are insufficient to classify these variants, functional assays with various cellular models are performed. We developed and applied a new syngeneic model of human cancer cells to test all variants of unknown significance in exon 18 identified by genetic testing of high-risk cancer patients in the Czech Republic, via introduction of constructs containing each of these variants into the wild-type allele of BRCA2-heterozygous DLD1 cells (BRCA2wt/Δex11). We found unaffected DNA repair function of BRCA2 in cell lines BRCA27997G>C/Δex11, BRCA28111C>T/Δex11, BRCA28149G>T/Δex11, BRCA28182G>A/Δex11, and BRCA28182G>T/Δex11, whereas the cell line BRCA28168A>G/Δex11 and the nonsense mutation carrying line BRCA28305G>T/Δex11 did affect protein function. Targeting the BRCA2 wild-type allele with a construct carrying the variant c.7988A> G resulted in incorporation exclusively into the already defective allele in all viable clones, strongly suggesting a detrimental phenotype. Our model thus offers a valuable tool for the functional evaluation of unclassified variants in the BRCA2 gene and provides a stable and distributable cellular resource for further research.
Assuntos
Proteína BRCA2/genética , Predisposição Genética para Doença , Testes Genéticos/métodos , Modelos Biológicos , Neoplasias/genética , Adulto , Idoso , Linhagem Celular Tumoral , República Tcheca , Análise Mutacional de DNA/métodos , Éxons/genética , Estudos de Viabilidade , Feminino , Humanos , Masculino , Cadeias de Markov , Anamnese , Pessoa de Meia-Idade , Mutação , Neoplasias/diagnóstico , Medição de Risco/métodosRESUMO
BACKGROUND: Even clearly resectable pancreatic cancer still has an unfavorable prognosis. Neoadjuvant or perioperative therapies might improve the prognosis of these patients. Thus, evaluation of perioperative chemotherapy in resectable pancreatic cancer in a prospective, randomized trial is warranted. A substantial improvement in overall survival of patients with metastatic pancreatic cancer with FOLFIRINOX and nab-paclitaxel/gemcitabine vs standard gemcitabine has been demonstrated in phase III-trials. Indeed nab-paclitaxel/gemcitabine has a more favorable toxicity profile compared to the FOLFIRINOX protocol and appears applicable in a perioperative setting. METHODS: NEONAX is an interventional, prospective, randomized, controlled, open label, two sided phase II study with an unconnected analysis of the results in both experimental arms against a fixed survival probability (38% at 18 months with adjuvant gemcitabine), NCT02047513. NEONAX will enroll 166 patients with resectable pancreatic ductal adenocarcinoma (≤ cT3, N0 or N1, cM0) in two arms: Arm A (perioperative arm): 2 cycles nab-paclitaxel (125 mg/m2)/gemcitabine (1000 mg/m2, d1, 8 and 15 of an 28 day-cycle) followed by tumor surgery followed by 4 cycles nab-paclitaxel/gemcitabine, Arm B (adjuvant arm): tumor surgery followed by 6 cycles nab-paclitaxel/gemcitabine. The randomization (1:1) is eminent to avoid allocation bias between the groups. Randomization is stratified for tumor stage (ct1/2 vs. cT3) and lymph node status (cN0 vs. cN1). Primary objective is disease free survival (DFS) at 18 months after randomization. Key secondary objectives are 3-year overall survival (OS) rate and DFS rate, progression during neoadjuvant therapy, R0 and R1 resection rate, quality of life and correlation of DFS, OS and tumor regression with pharmacogenomic markers, tumor biomarkers and molecular analyses (ctDNA, transcriptome, miRNA-arrays). In addition, circulating tumor-DNA will be analyzed in patients with the best and the worst responses to the neoadjuvant treatment. The study was initiated in March 2015 in 26 centers for pancreatic surgery in Germany. DISCUSSION: The NEONAX trial is an innovative study on resectable pancreatic cancer and currently one of the largest trials in this field of research. It addresses the question of the role of intensified perioperative treatment with nab-paclitaxel plus gemcitabine in resectable pancreatic cancers to improve disease-free survival and offers a unique potential for translational research. TRIAL REGISTRATION: ClinicalTrials.gov : NCT02047513, 08/13/2014.
Assuntos
Albuminas/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Ductal Pancreático/terapia , Desoxicitidina/análogos & derivados , Paclitaxel/uso terapêutico , Neoplasias Pancreáticas/terapia , Adulto , Idoso , Carcinoma Ductal Pancreático/mortalidade , Ensaios Clínicos Fase II como Assunto , Desoxicitidina/uso terapêutico , Progressão da Doença , Intervalo Livre de Doença , Combinação de Medicamentos , Fluoruracila/uso terapêutico , Alemanha/epidemiologia , Humanos , Irinotecano , Leucovorina/uso terapêutico , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Terapia Neoadjuvante/métodos , Compostos Organometálicos/uso terapêutico , Oxaliplatina , Pancreatectomia , Neoplasias Pancreáticas/mortalidade , Prognóstico , Estudos Prospectivos , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Análise de Sobrevida , Adulto Jovem , GencitabinaRESUMO
The phosphoinositide 3-kinase-related kinase ATR is a central regulator of the DNA damage response. Its chemical inhibition eliminates subsets of cancer cells in various tumor types. This effect is caused at least partly by the synthetically lethal relationship between ATR and certain DNA repair genes. In a previous screen using an siRNA library against DNA repair genes, we identified PRIM1, a part of the polymerase α-primase complex, as acting synthetically lethal with ATR. Applying a genetic ATR knock-in model of colorectal cancer cells, we confirmed that PRIM1 depletion inhibited proliferation of ATR-deficient cells and excluded artifacts due to clonal variation using an ATR reexpressing cell clone. We expanded these data by demonstrating in different cell lines that also chemical inhibition of ATR or its main effector kinase CHK1 reduces proliferation upon depletion of PRIM1. Mechanistically, PRIM1 depletion in ATR-deficient cells caused S-phase stasis in the absence of increased DNA damage followed by Wee1-mediated activation of caspase 8 and apoptosis. As PRIM1 inactivation sensitizes cancer cells to ATR and CHK1 inhibitors, mutations in PRIM1 or other components of the polymerase α-primase complex could represent novel targets for individualized tumor therapeutic approaches using ATR/CHK1 inhibitors, as has been previously demonstrated for POLD1, the catalytic subunit of polymerase δ.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Quinase 1 do Ponto de Checagem/antagonistas & inibidores , DNA Primase/antagonistas & inibidores , Resistencia a Medicamentos Antineoplásicos , Inibidores de Proteínas Quinases/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células , Expressão Gênica , Histonas/metabolismo , Humanos , Interferência de RNA , RNA Interferente Pequeno/genética , Mutações Sintéticas LetaisRESUMO
INTRODUCTION: Venous thromboembolism (VTE) is frequent in advanced pancreatic cancer (APC). Recent studies demonstrated that the Khorana score - an established risk stratification tool for VTE in cancer - performs poorly in identifying pancreatic cancer patients at high risk for VTE. MATERIALS AND METHODS: We performed a retrospective cohort study in order to define incidence, treatment and outcome of VTE as well as the performance of VTE risk stratification tools (Khorana score, CONKO score and aPTT ratio) in a "real life" clinical cohort of APC patients undergoing palliative chemotherapy. RESULTS AND CONCLUSIONS: One hundred and seventy-two eligible APC patients from our comprehensive cancer center were identified. VTE after start of palliative chemotherapy was diagnosed in 71 patients (41.3%). Most VTE events were asymptomatic (n=50, 29.1%) with only 21 symptomatic events (12.2%). On multivariate analysis - including age, performance status and carbohydrate antigen 19-9 (CA 19-9) - symptomatic VTE was an independent risk factor for death (hazard ratio [HR]: 2.22, 95% CI: 1.05-2.60, p<0.05). Khorana score, CONKO score and aPTT ratio alone were not able to predict the risk for symptomatic VTE. High risk patients could only be identified by using a combination of either Khorana or CONKO score with aPTT ratio (30% vs. 10% symptomatic VTE events in high vs. low risk patients, p<0.05). The combination of Khorana or CONKO score with aPTT thus may represent a novel risk stratification tool for symptomatic VTE in APC and should further be validated within prospective clinical trials.
Assuntos
Neoplasias Pancreáticas/complicações , Tromboembolia Venosa/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/patologia , Estudos Prospectivos , Estudos Retrospectivos , Fatores de Risco , Tromboembolia Venosa/epidemiologiaRESUMO
The tetrahydroisoquinoline trabectedin is a marine compound with approved activity against human soft-tissue sarcoma. It exerts antiproliferative activity mainly by specific binding to the DNA and inducing DNA double-strand breaks (DSB). As homologous recombination repair (HRR)-deficient tumors are more susceptible to trabectedin, hyperthermia-mediated on-demand induction of HRR deficiency represents a novel and promising strategy to boost trabectedin treatment. For the first time, we demonstrate enhancement of trabectedin effectiveness in human sarcoma cell lines by heat and characterize cellular events and molecular mechanisms related to heat-induced effects. Hyperthermic temperatures (41.8 or 43°C) enhanced significantly trabectedin-related clonogenic cell death and G2/M cell cycle arrest followed by cell type-dependent induction of apoptosis or senescence. Heat combination increased accumulation of γH2AX foci as key marker of DSBs. Expression of BRCA2 protein, an integral protein of the HRR machinery, was significantly decreased by heat. Consequently, recruitment of downstream RAD51 to γH2AX-positive repair foci was almost abolished indicating relevant impairment of HRR by heat. Accordingly, enhancement of trabectedin effectiveness was significantly augmented in BRCA2-proficient cells by hyperthermia and alleviated in BRCA2 knockout or siRNA-transfected BRCA2 knockdown cells. In peripheral blood mononuclear cells isolated from sarcoma patients, increased numbers of nuclear γH2AX foci were detected after systemic treatment with trabectedin and hyperthermia of the tumor region. The findings establish BRCA2 degradation by heat as a key factor for a novel treatment strategy that allows targeted chemosensitization to trabectedin and other DNA damaging antitumor drugs by on-demand induction of HRR deficiency.
Assuntos
Antineoplásicos Alquilantes/farmacologia , Proteína BRCA2/metabolismo , Dioxóis/farmacologia , Hipertermia Induzida , Reparo de DNA por Recombinação/efeitos dos fármacos , Reparo de DNA por Recombinação/efeitos da radiação , Tetra-Hidroisoquinolinas/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Caspases/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos da radiação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Resistencia a Medicamentos Antineoplásicos/efeitos da radiação , Histonas/metabolismo , Humanos , Modelos Biológicos , Ligação Proteica , Transporte Proteico , Proteólise/efeitos dos fármacos , Proteólise/efeitos da radiação , Rad51 Recombinase/metabolismo , Sarcoma/metabolismo , Sarcoma/patologia , Sarcoma/terapia , TrabectedinaRESUMO
PURPOSE: DNA repair defects due to detrimental BRCA2-mutations confer increased susceptibility towards DNA interstrand-crosslinking (ICL) agents and define patient subpopulations for individualized genotype-based cancer therapy. However, due to the side effects of these drugs, there is a need to identify additional agents, which could be used alone or in combination with ICL-agents. Therefore, we investigated whether BRCA2-mutations might also increase the sensitivity towards TRAIL-receptors (TRAIL-R)-targeting compounds. EXPERIMENTAL DESIGN: Two independent model systems were applied: a BRCA2 gene knockout and a BRCA2 gene complementation model. The effects of TRAIL-R-targeting compounds and ICL-agents on cell viability, apoptosis and cell cycle distribution were compared in BRCA2-proficient versus-deficient cancer cells in vitro. In addition, the effects of the TRAIL-R2-targeting antibody LBY135 were assessed in vivo using a murine tumor xenograft model. RESULTS: BRCA2-deficient cancer cells displayed an increased sensitivity towards TRAIL-R-targeting agents. These effects exceeded and were mechanistically distinguishable from the well-established effects of ICL-agents. In vitro, ICL-agents expectedly induced an early cell cycle arrest followed by delayed apoptosis, whereas TRAIL-R-targeting compounds caused early apoptosis without prior cell cycle arrest. In vivo, treatment with LBY135 significantly reduced the tumor growth of BRCA2-deficient cancer cells in a xenograft model. CONCLUSIONS: BRCA2 mutations strongly increase the in vitro- and in vivo-sensitivity of cancer cells towards TRAIL-R-mediated apoptosis. This effect is mechanistically distinguishable from the well-established ICL-hypersensitivity of BRCA2-deficient cells. Our study thus defines a new genetic subpopulation of cancers susceptible towards TRAIL-R-targeting compounds, which could facilitate novel therapeutic approaches for patients with BRCA2-deficient tumors.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteína BRCA2/genética , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Reagentes de Ligações Cruzadas/farmacologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/antagonistas & inibidores , Animais , Anticorpos Monoclonais Murinos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular/efeitos dos fármacos , Reparo do DNA/genética , Humanos , Camundongos , Interferência de RNA , RNA Interferente Pequeno/genéticaRESUMO
The phosphoinositide 3-kinase-related kinase ATR represents a central checkpoint regulator and mediator of DNA-repair. Its inhibition selectively eliminates certain subsets of cancer cells in various tumor types, but the underlying genetic determinants remain enigmatic. Here, we applied a synthetic lethal screen directed against 288 DNA-repair genes using the well-defined ATR knock-in model of DLD1 colorectal cancer cells to identify potential DNA-repair defects mediating these effects. We identified a set of DNA-repair proteins, whose knockdown selectively killed ATR-deficient cancer cells. From this set, we further investigated the profound synthetic lethal interaction between ATR and POLD1. ATR-dependent POLD1 knockdown-induced cell killing was reproducible pharmacologically in POLD1-depleted DLD1 cells and a panel of other colorectal cancer cell lines by using chemical inhibitors of ATR or its major effector kinase CHK1. Mechanistically, POLD1 depletion in ATR-deficient cells caused caspase-dependent apoptosis without preceding cell cycle arrest and increased DNA-damage along with impaired DNA-repair. Our data could have clinical implications regarding tumor genotype-based cancer therapy, as inactivating POLD1 mutations have recently been identified in small subsets of colorectal and endometrial cancers. POLD1 deficiency might thus represent a predictive marker for treatment response towards ATR- or CHK1-inhibitors that are currently tested in clinical trials.
Assuntos
Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , DNA Polimerase III/deficiência , Enzimas Reparadoras do DNA/antagonistas & inibidores , RNA Interferente Pequeno/genética , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/genética , Western Blotting , Ciclo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , Dano ao DNA/efeitos dos fármacos , DNA Polimerase III/genética , Reparo do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/genética , Inibidores Enzimáticos/farmacologia , Fluorometria , Ensaios de Triagem em Larga Escala , Histonas/metabolismo , Humanos , Mutação/genética , Proteínas Quinases/química , Proteínas Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
OBJECTIVES: IBDs have an increased risk for development of colorectal cancer (CRC). Here, we aimed at the characterisation of the functional role of Th17-associated transcription factors in sporadic and colitis-associated colon cancer in vivo. DESIGN: We used mice deficient or transgenic for the activating protein 1 family member basic leucine zipper transcription factor ATF-like (Batf) to evaluate the role of Th17 cells during sporadic and inflammation-induced colon carcinogenesis. We also studied the expression of Batf and RORγt in patients with IBD and CRC. RESULTS: Batf but not retinoic acid-related orphan receptor γt(RORγt) expression was significantly increased together with interleukin (IL) 23 expression in UC but not in Crohn's disease (CD) tissue samples. In CRC also Batf but not RORγt expression was increased and its expression correlated with the IL-23 and IL-23 receptor (IL-23R) expression. Finally, Batf but not RORγt was coexpressed with IL-17a, IL-23R and IL-6 within CRC-infiltrating CD4(+) T cells. Functional studies in mice revealed that Batf-dependent T cells are crucial regulators of sporadic and inflammation-induced CRC. Colitis-associated Batf(-/-) tumours lacked IL-17a(+)IL-23R(+)IL-6(+)CD4(+) T cells, hence displaying characteristics reminiscent of human CRC-infiltrating CD4(+) T cells. Strikingly, Batf(-/-) tumours contained low IL-23 but high IL-17a expression levels. Tumour formation and intratumoral IL-23 expression could be restored by administration of Hyper-IL-6 consisting of IL-6 and soluble IL-6 receptor. CONCLUSIONS: Batf-dependent IL-23R(+)IL-6(+)CD4(+) Th17 cells critically control IL-23 driven colitis-associated tumour formation and the progression of sporadic colon tumours. Batf-dependent IL-23R(+) T cells represent a potential future therapeutic target limiting CRC progression.
Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Colite Ulcerativa/metabolismo , Neoplasias do Colo/metabolismo , Interleucina-23/metabolismo , Células Th17/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina Básica/deficiência , Fatores de Transcrição de Zíper de Leucina Básica/genética , Transformação Celular Neoplásica , Colite Ulcerativa/patologia , Neoplasias do Colo/patologia , Doença de Crohn/metabolismo , Humanos , Interleucina-17/metabolismo , Interleucina-23/genética , Interleucina-6/genética , Interleucina-6/metabolismo , Interleucina-6/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , RNA Mensageiro/metabolismo , Receptores de Interleucina/metabolismo , Receptores de Interleucina-6/metabolismo , Transdução de SinaisRESUMO
Tivantinib, a c-MET inhibitor, is investigated as a second-line treatment of HCC. It was shown that c-MET overexpression predicts its efficacy. Therefore, a phase-3 trial of tivantinib has been initiated to recruit "c-MET-high" patients only. However, recent evidence indicates that the anticancer activity of tivantinib is not due to c-MET inhibition, suggesting that c-MET is a predictor of response to this compound rather than its actual target. By assessing the mechanisms underlying the anticancer properties of tivantinib we showed that this agent causes apoptosis and cell cycle arrest by inhibiting the anti-apoptotic molecules Mcl-1 and Bcl-xl, and by increasing Cyclin B1 expression regardless of c-MET status. However, we found that tivantinib might antagonize the antiapoptotic effects of c-MET activation since HGF enhanced the expression of Mcl-1 and Bcl-xl. In summary, we show that the activity of tivantinib is independent of c-MET and describe Mcl-1, Bcl-xl and Cyclin B1 as effectors of its antineoplastic effects in HCC cells. We suggest that the predictive effect of c-MET expression in part reflects the c-MET-driven overexpression of Mcl-1 and Bcl-xl in c-MET-high patients and that these molecules are considered as possible response predictors.
Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-met/metabolismo , Pirrolidinonas/farmacologia , Quinolinas/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/metabolismo , Colangiocarcinoma/patologia , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Ciclina B1/metabolismo , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/biossíntese , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Proteína bcl-X/metabolismoRESUMO
We previously established a role for HSP27 as a predictive marker for therapeutic response towards gemcitabine in pancreatic cancer. Here, we investigate the underlying mechanisms of HSP27-mediated gemcitabine sensitivity. Utilizing a pancreatic cancer cell model with stable HSP27 overexpression, cell cycle arrest and apoptosis induction were analysed by flow cytometry, nuclear staining, immunoblotting and mitochondrial staining. Drug sensitivity studies were performed by proliferation assays. Hyperthermia was simulated using mild heat shock at 41.8°C. Upon gemcitabine treatment, HSP27-overexpressing cells displayed an early S-phase arrest subsequently followed by a strongly increased sub-G1 fraction. Apoptosis was characterized by PARP-, CASPASE 3-, CASPASE 8-, CASPASE 9- and BIM- activation along with a mitochondrial membrane potential loss. It was reversible through chemical caspase inhibition. Importantly, gemcitabine sensitivity and PARP cleavage were also elicited by heat shock-induced HSP27 overexpression, although to a smaller extent, in a panel of pancreatic cancer cell lines. Finally, HSP27-overexpressing pancreatic cancer cells displayed an increased sensitivity also towards death receptor-targeting agents, suggesting another pro-apoptotic role of HSP27 along the extrinsic apoptosis pathway. Taken together, in contrast to the well-established anti-apoptotic properties of HSP27 in cancer, our study reveals novel pro-apoptotic functions of HSP27-mediated through both the intrinsic and the extrinsic apoptotic pathways-at least in pancreatic cancer cells. HSP27 could represent a predictive marker of therapeutic response towards specific drug classes in pancreatic cancer and provides a novel molecular rationale for current clinical trials applying the combination of gemcitabine with regional hyperthermia in pancreatic cancer patients.
Assuntos
Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Desoxicitidina/análogos & derivados , Proteínas de Choque Térmico HSP27/genética , Neoplasias Pancreáticas/tratamento farmacológico , Fase S/efeitos dos fármacos , Apoptose/genética , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Desoxicitidina/farmacologia , Proteínas de Choque Térmico , Humanos , Chaperonas Moleculares , Pâncreas/efeitos dos fármacos , Neoplasias Pancreáticas/genética , Fase S/genética , GencitabinaRESUMO
PURPOSE: It has not yet been clearly defined whether anaplastic lymphoma kinase (ALK) expression can be detected in pancreatic ductal adenocarcinoma (PDAC). METHODS: Within a retrospective study, archival PDAC surgical specimens were screened for ALK expression in tumor and normal tissue by immunohistochemistry (IHC) with the use of a specific ALK detection kit on a tissue microarray (TMA). RESULTS: PDAC tumor tissue was available from 99 resected cases: fifty-eight out of 99 patients (59 %) had nodal-positive disease, and 80 patients (81 %) had pT3 tumors. Forty-nine patients underwent R0 resection, and in 48 cases, resection status was classified R1. Regarding ALK expression, five cases showed faint immunoreactivity on TMA, which was negative on whole mount sections. All other 94 cases showed no ALK expression. CONCLUSION: In 99 PDAC cases, no ALK expression was detected by IHC; ALK thus may not serve as a relevant drug target in PDAC.
Assuntos
Carcinoma Ductal Pancreático/genética , Expressão Gênica/genética , Neoplasias Pancreáticas/genética , Receptores Proteína Tirosina Quinases/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Quinase do Linfoma Anaplásico , Feminino , Humanos , Imuno-Histoquímica/métodos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias PancreáticasRESUMO
BACKGROUND: Colorectal cancers carrying the B-Raf V600E-mutation are associated with a poor prognosis. The purpose of this study was to identify B-RafV600E-mediated traits of cancer cells in a genetic in vitro model and to assess the selective sensitization of B-RafV600E-mutant cancer cells towards therapeutic agents. METHODS: Somatic cell gene targeting was used to generate subclones of the colorectal cancer cell line RKO containing either wild-type or V600E-mutant B-Raf kinase. Cell-biologic analyses were performed in order to link cancer cell traits to the BRAF-mutant genotype. Subsequently, the corresponding tumor cell clones were characterized pharmacogenetically to identify therapeutic agents exhibiting selective sensitivity in B-RafV600E-mutant cells. RESULTS: Genetic targeting of mutant BRAF resulted in restoration of sensitivity to serum starvation-induced apoptosis and efficiently inhibited cell proliferation in the absence of growth factors. Among tested agents, the B-Raf inhibitor dabrafenib was found to induce a strong V600E-dependent shift in cell viability. In contrast, no differential sensitizing effect was observed for conventional chemotherapeutic agents (mitomycin C, oxaliplatin, paclitaxel, etoposide, 5-fluorouracil), nor for the targeted agents cetuximab, sorafenib, vemurafenib, RAF265, or for inhibition of PI3 kinase. Treatment with dabrafenib efficiently inhibited phosphorylation of the B-Raf downstream targets Mek 1/2 and Erk 1/2. CONCLUSION: Mutant BRAF alleles mediate self-sufficiency of growth signals and serum starvation-induced resistance to apoptosis. Targeting of the BRAF mutation leads to a loss of these hallmarks of cancer. Dabrafenib selectively inhibits cell viability in B-RafV600E mutant cancer cells.
Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Neoplásica da Expressão Gênica , Imidazóis/farmacologia , Oximas/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Colo/efeitos dos fármacos , Colo/metabolismo , Colo/patologia , Meios de Cultura Livres de Soro/farmacologia , Genótipo , Humanos , MAP Quinase Quinase 1/antagonistas & inibidores , MAP Quinase Quinase 1/genética , MAP Quinase Quinase 1/metabolismo , MAP Quinase Quinase 2/antagonistas & inibidores , MAP Quinase Quinase 2/genética , MAP Quinase Quinase 2/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Mutação , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de SinaisRESUMO
INTRODUCTION: Agonistic antibodies targeting TRAIL-receptors 1 and 2 (TRAIL-R1 and TRAIL-R2) are being developed as a novel therapeutic approach in cancer therapy including pancreatic cancer. However, the cellular distribution of these receptors in primary pancreatic cancer samples has not been sufficiently investigated and no study has yet addressed the issue of their prognostic significance in this tumor entity. AIMS AND METHODS: Applying tissue microarray (TMA) analysis, we performed an immunohistochemical assessment of TRAIL-receptors in surgical samples from 84 consecutive patients affected by pancreatic adenocarcinoma and in 26 additional selected specimens from patients with no lymph nodes metastasis at the time of surgery. The prognostic significance of membrane staining and staining intensity for TRAIL-receptors was evaluated. RESULTS: The fraction of pancreatic cancer samples with positive membrane staining for TRAIL-R1 and TRAIL-R2 was lower than that of cells from surrounding non-tumor tissues (TRAIL-R1: p<0.001, TRAIL-R2: pâ=â0.006). In addition, subgroup analyses showed that loss of membrane staining for TRAIL-R2 was associated with poorer prognosis in patients without nodal metastases (multivariate Cox regression analysis, Hazard Ratio: 0.44 [95% confidence interval: 0.22-0.87]; pâ=â0.019). In contrast, analysis of decoy receptors TRAIL-R3 and -R4 in tumor samples showed an exclusively cytoplasmatic staining pattern and no prognostic relevance. CONCLUSION: This is a first report on the prognostic significance of TRAIL-receptors expression in pancreatic cancer showing that TRAIL-R2 might represent a prognostic marker for patients with early stage disease. In addition, our data suggest that loss of membrane-bound TRAIL-receptors could represent a molecular mechanism for therapeutic failure upon administration of TRAIL-receptors-targeting antibodies in pancreatic cancer. This hypothesis should be evaluated in future clinical trials.
Assuntos
Linfonodos/metabolismo , Linfonodos/patologia , Metástase Linfática/patologia , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/cirurgia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/deficiência , Idoso , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/cirurgia , Membrana Celular/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Pâncreas/metabolismo , Pâncreas/patologia , Neoplasias Pancreáticas/patologia , Prognóstico , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Coloração e RotulagemRESUMO
BACKGROUND: The fact that the receptors for the TNF-related apoptosis inducing ligand (TRAIL) are almost invariably expressed in colorectal cancer (CRC) represents the rationale for the employment of TRAIL-receptors targeting compounds for the therapy of patients affected by this tumor. Yet, first reports on the use of these bioactive agents provided disappointing results. We therefore hypothesized that loss of membrane-bound TRAIL-R might be a feature of some CRC and that the evaluation of membrane staining rather than that of the overall expression of TRAIL-R might predict the response to TRAIL-R targeting compounds in this tumor. AIM AND METHODS: Thus, we evaluated the immunofluorescence pattern of TRAIL-receptors and E-cadherin to assess the fraction of membrane-bound TRAIL-receptors in 231 selected patients with early-stage CRC undergoing surgical treatment only. Moreover, we investigated whether membrane staining for TRAIL-receptors as well as the presence of KRAS mutations or of microsatellite instability (MSI) had an effect on survival and thus a prognostic effect. RESULTS: As expected, almost all CRC samples stained positive for TRAIL-R1 and 2. Instead, membrane staining for these receptors was positive in only 71% and 16% of samples respectively. No correlation between KRAS mutation status or MSI-phenotype and prognosis could be detected. TRAIL-R1 staining intensity correlated with survival in univariate analysis, but only membranous staining of TRAIL-R1 and TRAIL-R2 on cell membranes was an independent predictor of survival (cox multivariate analysis: TRAIL-R1: p = 0.019, RR 2.06[1.12-3.77]; TRAIL-R2: p = 0.033, RR 3.63[1.11-11.84]). CONCLUSIONS: In contrast to the current assumptions, loss of membrane staining for TRAIL-receptors is a common feature of early stage CRC which supersedes the prognostic significance of their staining intensity. Failure to achieve therapeutic effects in recent clinical trials using TRAIL-receptors targeting compounds might be due to insufficient selection of patients bearing tumors with membrane-bound TRAIL-receptors.