RESUMEN
AIMS: Maternally inherited diabetes and deafness (MIDD) is a rare form of adult-onset diabetes that can be difficult to diagnose due to its variable clinical phenotype. Transfer RNA-derived small fragments are a novel, emerging class of small non-coding RNAs (sncRNAs) that have significant potential as serum biomarkers due to their stress-induced generation, abundance, stability and ease of detection. METHODS: We investigated the levels of tiRNA 5'ValCAC (alone and in combination with miR-23b-3p) identified from small RNA sequencing studies in serum samples from healthy controls, type 1 diabetes, type 2 diabetes and MIDD subjects. RESULTS: Serum levels of 5'ValCAC were reduced in MIDD and type 2 diabetes subjects compared to controls. Type 2 diabetes subjects had higher serum levels of miR-23b-3p compared to all other subjects. Receiver Operating Characteristic analysis showed the potential of 5'ValCAC and miR-23b-3p as MIDD biomarkers, with the combination showing excellent separation from type 2 diabetes subjects. CONCLUSIONS: This is the first report showing altered serum levels of tiRNAs in diabetes subjects. The combined use of 5'ValCAC and miR-23b-3p as serum biomarkers could potentially differentiate between MIDD subjects and type 2 diabetes subjects.
Asunto(s)
Sordera , Diabetes Mellitus Tipo 2 , MicroARNs , Enfermedades Mitocondriales , Adulto , Humanos , Diabetes Mellitus Tipo 2/genética , Biomarcadores , ARN de Transferencia , MicroARNs/genéticaRESUMEN
BACKGROUND: New precision medicine therapies are urgently required for glioblastoma (GBM). However, to date, efforts to subtype patients based on molecular profiles have failed to direct treatment strategies. We hypothesised that interrogation of the GBM tumour microenvironment (TME) and identification of novel TME-specific subtypes could inform new precision immunotherapy treatment strategies. MATERIALS AND METHODS: A refined and validated microenvironment cell population (MCP) counter method was applied to >800 GBM patient tumours (GBM-MCP-counter). Specifically, partition around medoids (PAM) clustering of GBM-MCP-counter scores in the GLIOTRAIN discovery cohort identified three novel patient clusters, uniquely characterised by TME composition, functional orientation markers and immune checkpoint proteins. Validation was carried out in three independent GBM-RNA-seq datasets. Neoantigen, mutational and gene ontology analysis identified mutations and uniquely altered pathways across subtypes. The longitudinal Glioma Longitudinal AnalySiS (GLASS) cohort and three immunotherapy clinical trial cohorts [treatment with neoadjuvant/adjuvant anti-programmed cell death protein 1 (PD-1) or PSVRIPO] were further interrogated to assess subtype alterations between primary and recurrent tumours and to assess the utility of TME classifiers as immunotherapy biomarkers. RESULTS: TMEHigh tumours (30%) displayed elevated lymphocyte, myeloid cell immune checkpoint, programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 transcripts. TMEHigh/mesenchymal+ patients featured tertiary lymphoid structures. TMEMed (46%) tumours were enriched for endothelial cell gene expression profiles and displayed heterogeneous immune populations. TMELow (24%) tumours were manifest as an 'immune-desert' group. TME subtype transitions upon recurrence were identified in the longitudinal GLASS cohort. Assessment of GBM immunotherapy trial datasets revealed that TMEHigh patients receiving neoadjuvant anti-PD-1 had significantly increased overall survival (P = 0.04). Moreover, TMEHigh patients treated with adjuvant anti-PD-1 or oncolytic virus (PVSRIPO) showed a trend towards improved survival. CONCLUSIONS: We have established a novel TME-based classification system for application in intracranial malignancies. TME subtypes represent canonical 'termini a quo' (starting points) to support an improved precision immunotherapy treatment approach.
Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/tratamiento farmacológico , Microambiente Tumoral , Recurrencia Local de Neoplasia , Inmunoterapia/métodos , Neoplasias Encefálicas/tratamiento farmacológicoRESUMEN
Previous research has identified differences in mutation frequency in genes implicated in chemotherapy resistance between mucinous and non-mucinous colorectal cancers (CRC). We hypothesized that outcomes in mucinous and non-mucinous CRC may be influenced by expression of genes responsible for chemotherapy resistance. Gene expression data from primary tumor samples were extracted from The Cancer Genome Atlas PanCancer Atlas. The distribution of clinical, pathological, and gene expression variables was compared between 74 mucinous and 521 non-mucinous CRCs. Predictors of overall survival (OS) were assessed in a multivariate analysis. Kaplan-Meier curves were constructed to compare survival according to gene expression using the log rank test. The median expression of 5-FU-related genes TYMS, TYMP, and DYPD was significantly higher in mucinous CRC compared to non-mucinous CRC (p < 0.001, p = 0.003, p < 0.001, respectively). The median expression of oxaliplatin-related genes ATP7B and SRPK1 was significantly reduced in mucinous versus non-mucinous CRC (p = 0.004, p = 0.007, respectively). At multivariate analysis, age (odds ratio (OR) = 0.96, p < 0.001), node positive disease (OR = 0.49, p = 0.005), and metastatic disease (OR = 0.32, p < 0.001) remained significant negative predictors of OS, while high SRPK1 remained a significant positive predictor of OS (OR = 1.59, p = 0.037). Subgroup analysis of rectal cancers demonstrated high SRPK1 expression was associated with significantly longer OS compared to low SRPK1 expression (p = 0.011). This study highlights that the molecular differences in mucinous CRC and non-mucinous CRC extend to chemotherapy resistance gene expression. SRPK1 gene expression was associated with OS, with a prognostic role identified in rectal cancers.
Asunto(s)
Neoplasias Colorrectales/genética , Resistencia a Antineoplásicos/genética , Inactivación Metabólica/genética , Anciano , ATPasas Transportadoras de Cobre/genética , Femenino , Expresión Génica/genética , Humanos , Masculino , Pronóstico , Proteínas Serina-Treonina Quinasas/genéticaRESUMEN
BACKGROUND: Response to neoadjuvant chemoradiotherapy (CRT) in locally advanced rectal cancer is variable. Identification of biomarkers to predict response is desirable in order to provide prognostic information and targeted therapy. Several studies have investigated microsatellite instability (MSI) as a predictor of response to CRT with contradictory results. This study aims to clarify the effect of MSI status on response to CRT in locally advanced rectal cancer through systematic review and meta-analysis. METHODS: A systematic search of PubMed, Embase and Cochrane databases was performed for all studies relating to MSI and response to CRT in rectal cancer using the search algorithm (Microsatellite Instability) AND (Chemoradiotherapy) AND (Rectal Cancer). From each included study the number of patients with MSI tumors and Microsatellite Stable (MSS) tumors and the numbers achieving pathological complete response (pCR) were recorded. Pooled outcome measures were determined using a random effects model and the odds ratio estimated with variance and 95% confidence interval. RESULTS: Nine published studies were identified reporting data on MSI and its effect on outcome after CRT for locally advanced rectal cancer. Five studies describing 5,877 patients included data on MSI and the number of patients achieving pCR. There was no significant association between MSI and pCR (MSI Vs MSS: 10.1% Vs 6.6%, OR 1.38, 95% CI: 0.7-2.72, p = 0.35). CONCLUSION: This meta-analysis concludes that there appears to be no significant difference in pCR rate following CRT in patients with MSI versus MSS rectal tumors.
Asunto(s)
Quimioradioterapia Adyuvante/métodos , Inestabilidad de Microsatélites , Terapia Neoadyuvante/métodos , Neoplasias del Recto/patología , Humanos , Pronóstico , Neoplasias del Recto/genética , Neoplasias del Recto/terapiaRESUMEN
Glioblastoma represents the most common primary malignancy of the central nervous system in adults and remains a largely incurable disease. The elucidation of disease subtypes based on mutational profiling, gene expression and DNA methylation has so far failed to translate into improved clinical outcomes. However, new knowledge emerging from the subtyping effort in the IDH-wild-type setting may provide directions for future precision therapies. Here, we review recent learnings in the field, and further consider how tumour microenvironment differences across subtypes may reveal novel contexts of vulnerability. We discuss recent treatment approaches and ongoing trials in the IDH-wild-type glioblastoma setting, and propose an integrated discovery stratagem incorporating multi-omics, single-cell technologies and computational approaches.
Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Adulto , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/genética , Metilación de ADN , Glioblastoma/tratamiento farmacológico , Glioblastoma/genética , Humanos , Isocitrato Deshidrogenasa/genética , Mutación , Medicina de Precisión , Microambiente TumoralRESUMEN
BACKGROUND: Mucinous differentiation occurs in 5-15 per cent of colorectal adenocarcinomas. This subtype of colorectal cancer responds poorly to chemoradiotherapy and has a worse prognosis. The genetic aetiology underpinning this cancer subtype lacks consensus. The aim of this study was to use meta-analytical techniques to clarify the molecular associations of mucinous colorectal cancer. METHODS: This study adhered to MOOSE guidelines. Databases were searched for studies comparing KRAS, BRAF, microsatellite instability (MSI), CpG island methylator phenotype (CIMP), p53 and p27 status between patients with mucinous and non-mucinous colorectal adenocarcinoma. A random-effects model was used for analysis. RESULTS: Data from 46 studies describing 17 746 patients were included. Mucinous colorectal adenocarcinoma was associated positively with KRAS (odds ratio (OR) 1·46, 95 per cent c.i. 1·08 to 2·00, P = 0·014) and BRAF (OR 3·49, 2·50 to 4·87; P < 0·001) mutation, MSI (OR 3·98, 3·30 to 4·79; P < 0·001) and CIMP (OR 3·56, 2·85 to 4·43; P < 0·001), and negatively with altered p53 expression (OR 0·46, 0·31 to 0·67; P < 0·001). CONCLUSION: The genetic origins of mucinous colorectal adenocarcinoma are predominantly associated with BRAF, MSI and CIMP pathways. This pattern of molecular alterations may in part explain the resistance to standard chemotherapy regimens seen in mucinous adenocarcinoma.
Asunto(s)
Adenocarcinoma Mucinoso/genética , Biomarcadores de Tumor/genética , Neoplasias Colorrectales/genética , Regulación Neoplásica de la Expresión Génica , Adenocarcinoma Mucinoso/patología , Neoplasias Colorrectales/patología , Islas de CpG/genética , Metilación de ADN , Humanos , Inestabilidad de Microsatélites , Modelos Estadísticos , Mutación , Fenotipo , Antígeno Nuclear de Célula en Proliferación/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteína p53 Supresora de Tumor/genéticaRESUMEN
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
RESUMEN
Bevacizumab (bvz) is a first choice anti-angiogenic drug in oncology and is primarily administered in combination with chemotherapy. It has been hypothesized that anti-angiogenic drugs enhance efficacy of cytotoxic drugs by "normalizing" abnormal tumor vessels and improving drug penetration. Nevertheless, the clinical relevance of this phenomenon is still unclear with several studies over recent years suggesting an opposing relationship. Herein, we sought to develop a new computational tool to interrogate anti-angiogenic drug scheduling with particular application in the setting of colorectal cancer (CRC). Specifically, we have employed a mathematical model of vascular tumour growth which interrogates the impact of anti-angiogenic treatment and chemotherapeutic treatment on tumour volume. Model predictions were validated using CRC xenografts which underwent treatment with a clinically relevant combinatorial anti-angiogenic regimen. Bayesian model selection revealed the most appropriate term for capturing the effect of treatments on the tumour size, and provided insights into a switch-like dependence of FOLFOX delivery on the tumour vasculature. Our experimental data and mathematical model suggest that delivering chemotherapy prior to bvz may be optimal in the colorectal cancer setting.
Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Esquema de Medicación , Neovascularización Patológica/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Bevacizumab/uso terapéutico , Proliferación Celular/efectos de los fármacos , Citotoxinas/uso terapéutico , Fluorouracilo/uso terapéutico , Humanos , Leucovorina/uso terapéutico , Modelos Teóricos , Compuestos Organoplatinos/uso terapéuticoRESUMEN
Colorectal cancer (CRC) is one of the most common cancers in the Western world. 5-Fluorouracil (5FU)-based chemotherapy (CT) remains the mainstay treatment of CRC in the advanced setting, and activates executioner caspases in target cells. Executioner caspases are key proteins involved in cell disassembly during apoptosis. Activation of executioner caspases also has a role in tissue regeneration and repopulation by stimulating signal transduction and cell proliferation in neighbouring, non-apoptotic cells as reported recently. Tissue microarrays (TMAs) consisting of tumour tissue from 93 stage II and III colon cancer patients were analysed by immunohistochemistry. Surprisingly, patients with low levels of active Caspase-3 had an increased disease-free survival time. This was particularly pronounced in patients who received 5FU-based adjuvant CT. In line with this observation, lower serum levels of active Caspase-3 were found in patients with metastasised CRC who revealed stable disease or tumour regression compared with those with disease progression. The role of Caspase-3 in treatment responses was explored further in primary human tumour explant cultures from fresh patient tumour tissue. Exposure of explant cultures to 5FU-based CT increased the percentage of cells positive for active Caspase-3 and Terminal Deoxynucleotidyl Transferase dUTP Nick end Labelling (TUNEL), but also the expression of regeneration and proliferation markers ß-Catenin and Ki-67, as well as cyclooxygenase-2 (COX-2). Of note, selective inhibition of Caspase-3 with Ac-DNLD-CHO, a selective, reversible inhibitor of Caspase-3, significantly reduced the expression of proliferation markers as well as COX-2. Inhibition of COX-2 with aspirin or celecoxib did not affect Caspase-3 levels but also reduced Ki-67 and ß-Catenin levels, suggesting that Caspase-3 acted via COX-2 to stimulate cell proliferation and tissue regeneration. This indicates that low levels of active Caspase-3 may represent a new predictor of CT responsiveness, and inhibition of Caspase-3, or antagonising downstream effectors of Caspase-3 paracrine signalling, such as COX-2 may improve patient outcomes following CT in advanced CRC.
Asunto(s)
Caspasa 3/metabolismo , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/enzimología , Fluorouracilo/farmacología , Antimetabolitos Antineoplásicos/farmacología , Caspasa 3/genética , Proliferación Celular/efectos de los fármacos , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Femenino , Humanos , Inmunohistoquímica , Masculino , Análisis de Matrices TisularesRESUMEN
The effects of autophagy on cell death are highly contextual and either beneficial or deleterious. One prime example for this dual function of autophagy is evidenced by the cell responses to the BH3 mimetic AT-101 that is known to induce either apoptotic or autophagy-dependent cell death in different settings. Based on previous reports, we hypothesized that the expression levels of pro-survival Bcl-2 family members may be key determinants for the respective death mode induced by AT-101. Here we investigated the role of autophagy in the response of MCF7 breast cancer cells to AT-101. AT-101 treatment induced a prominent conversion of LC3-I to LC3-II and apoptotic cell death characterized by the appearance of Annexin-positive/PI-negative early apoptotic cells and PARP cleavage. Inhibition of the autophagy pathway, either through application of 3-MA or by lentiviral knockdown of ATG5, strongly potentiated cell death, indicating a pro-survival function of autophagy. Overexpression of wild type Bcl-xL significantly diminished the net amount of AT-101-induced cell death, but failed to alter the death-enhancing effects of the ATG5 knockdown. This was also observed with the organelle-specific variants Bcl-xL-ActA and Bcl-2-ActA (mitochondrial) as well as Bcl-xL-cb5 and Bcl-2-cb5 (ER) which all reduced AT-101-induced cell death, but did not affect the death-enhancing effects of 3-MA. Collectively, our data indicate that in apoptosis-proficient MCF7 cells, AT-101 triggers Bcl-2- and Bcl-xL-dependent apoptosis and a cytoprotective autophagy response that is independent of the expression and subcellular localization of Bcl-xL and Bcl-2.
Asunto(s)
Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Neoplasias de la Mama/patología , Gosipol/análogos & derivados , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteína bcl-X/genética , Apoptosis/genética , Autofagia/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Citoprotección/efectos de los fármacos , Citoprotección/genética , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Gosipol/farmacología , Humanos , Células MCF-7 , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Células Tumorales Cultivadas , Proteína bcl-X/metabolismoRESUMEN
BACKGROUND: Resistance to temozolomide (TMZ) greatly limits chemotherapeutic effectiveness in glioblastoma (GBM). Here we analysed the ability of the Inhibitor-of-apoptosis-protein (IAP) antagonist birinapant to enhance treatment responses to TMZ in both commercially available and patient-derived GBM cells. METHODS: Responses to TMZ and birinapant were analysed in a panel of commercial and patient-derived GBM cell lines using colorimetric viability assays, flow cytometry, morphological analysis and protein expression profiling of pro- and antiapoptotic proteins. Responses in vivo were analysed in an orthotopic xenograft GBM model. RESULTS: Single-agent treatment experiments categorised GBM cells into TMZ-sensitive cells, birinapant-sensitive cells, and cells that were insensitive to either treatment. Combination treatment allowed sensitisation to therapy in only a subset of resistant GBM cells. Cell death analysis identified three principal response patterns: Type A cells that readily activated caspase-8 and cell death in response to TMZ while addition of birinapant further sensitised the cells to TMZ-induced cell death; Type B cells that readily activated caspase-8 and cell death in response to birinapant but did not show further sensitisation with TMZ; and Type C cells that showed no significant cell death or moderately enhanced cell death in the combined treatment paradigm. Furthermore, in vivo, a Type C patient-derived cell line that was TMZ-insensitive in vitro and showed a strong sensitivity to TMZ and TMZ plus birinapant treatments. CONCLUSIONS: Our results demonstrate remarkable differences in responses of patient-derived GBM cells to birinapant single and combination treatments, and suggest that therapeutic responses in vivo may be greatly affected by the tumour microenvironment.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Apoptosis/efectos de los fármacos , Neoplasias Encefálicas/patología , Dacarbazina/análogos & derivados , Dipéptidos/farmacología , Glioblastoma/patología , Indoles/farmacología , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Animales , Western Blotting , Caspasa 8/efectos de los fármacos , Caspasa 8/metabolismo , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Dacarbazina/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Citometría de Flujo , Humanos , Técnicas In Vitro , Ratones , Ratones Endogámicos NOD , Ratones SCID , Microscopía de Contraste de Fase , Trasplante de Neoplasias , Temozolomida , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: The mainstay of treatment in rectal cancer is neoadjuvant radio chemotherapy prior to surgery, in an attempt to downstage the tumour, allowing for more complete removal during surgery. In 40 % of cases however, this neoadjuvant radio chemotherapy fails to achieve tumour regression, partly due insufficient apoptosis signaling. X-linked Inhibitor of Apoptosis Protein (XIAP) is an anti-apoptotic protein that has been reported to contribute to disease progression and chemotherapy resistance. METHODS: We obtained rectal biopsy normal and matched tumour tissue from 29 rectal cancer patients with varying degrees of tumour regression, and using Western blot, examined anti-apoptotic XIAP and pro-apoptotic Smac protein levels in these tissues, with the aim to examine whether disturbed XIAP/Smac levels may be an indicator of neoadjuvant radio chemotherapy resistance. Expression of inhibitor of apoptosis proteins cIAP-1 and cIAP-2 was also examined. RESULTS: We found that levels of XIAP increased in accordance with the degree of radio chemotherapy resistance of the tissue. Levels of this protein were also significantly higher in tumour tissue, compared to matched normal tissue in highly resistant tissue. In contrast, Smac protein levels did not increase with radio chemotherapy resistance, and the protein was similarly expressed in normal and tumour tissue, indicating a shift in the balance of these proteins. Post treatment surgical resection tissue was available for 8 patients. When we compared matched tissue pre- and post- radio chemotherapy we found that XIAP levels increased significantly during treatment in both normal and tumour tissue, while Smac levels did not change. cIAP-1 and cIAP-2 levels were not differentially expressed in varying degrees of radio chemotherapy resistance, and neoadjuvant therapy did not alter expression of these proteins. CONCLUSION: These data indicate that disturbance of the XIAP/Smac balance may be a driver of radio chemotherapy resistance, and hence high levels of XIAP may be a useful indicator of neoadjuvant radio chemotherapy resistance in rectal cancer. Moreover, as XIAP levels increase with radio chemotherapy it is possible that a subset of more resistant tumour cells survive this treatment and may be resistant to further adjuvant treatment. Patients with resistant tumours highly expressing XIAP may benefit from alternative treatment strategies, such as Smac mimetics post neoadjuvant radio chemotherapy.
Asunto(s)
Biomarcadores de Tumor/análisis , Quimioradioterapia , Resistencia a Antineoplásicos/fisiología , Péptidos y Proteínas de Señalización Intracelular/análisis , Proteínas Mitocondriales/análisis , Terapia Neoadyuvante , Proteínas de Neoplasias/análisis , Tolerancia a Radiación/fisiología , Neoplasias del Recto/química , Proteína Inhibidora de la Apoptosis Ligada a X/análisis , Adulto , Anciano , Antimetabolitos Antineoplásicos/farmacología , Antimetabolitos Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Proteínas Reguladoras de la Apoptosis , Proteína 3 que Contiene Repeticiones IAP de Baculovirus , Biomarcadores de Tumor/biosíntesis , Biomarcadores de Tumor/genética , Femenino , Fluorouracilo/farmacología , Fluorouracilo/uso terapéutico , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de la radiación , Humanos , Proteínas Inhibidoras de la Apoptosis/análisis , Proteínas Inhibidoras de la Apoptosis/biosíntesis , Proteínas Inhibidoras de la Apoptosis/genética , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Persona de Mediana Edad , Proteínas Mitocondriales/biosíntesis , Proteínas Mitocondriales/genética , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Neoplasias del Recto/patología , Neoplasias del Recto/terapia , Ubiquitina-Proteína Ligasas/análisis , Ubiquitina-Proteína Ligasas/biosíntesis , Ubiquitina-Proteína Ligasas/genética , Proteína Inhibidora de la Apoptosis Ligada a X/biosíntesis , Proteína Inhibidora de la Apoptosis Ligada a X/genéticaRESUMEN
An accumulation of misfolded proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR) mediated via the activation of three transmembrane proteins IRE1, PERK and ATF6. Signalling through these proteins is aimed at enhancing the ER folding capacity and reducing the folding load. If these processes fail to re-establish protein homeostasis within the ER, then cell death prevails via apoptosis. How the shift from pro-survival to pro-apoptotic signalling is regulated remains unclear with both IRE1 and PERK signalling associated with pro-survival as well as pro-apoptotic signalling. To investigate the temporal activation of IRE1 and PERK in live cells and their relationship to cellular fate, we devised single cell reporters for both ER stress signalling branches. SH-SY5Y neural cells stably expressing these fluorescent protein reporter constructs to monitor IRE1-splicing activity and PERK-mediated ATF4-translation were imaged using single cell and high content time lapse live cell microscopy. We could correlate an early onset and attenuation of XBP1 splicing in the IRE1-reporter cells as cytoprotective. Indeed, silencing of IRE1 expression using shRNA inhibited splicing of XBP1 resulting in an early onset of cell death. In contrast, in the PERK-reporter cells, we observed that a slow rate of ATF4-translation and late re-initiation of general translation coincided with cells which were resistant to ER stress-induced cell death. Interestingly, whereas silencing of PERK did not affect overall levels of cell death in response to ER stress, it did increase sensitivity to ER stressors at early time points following treatment. Our results suggest that apoptosis activation in response to ER stress is not caused by a preferential activation of a single UPR branch, or by a switch from one branch to the other. Rather, our data indicated that the relative timing of IRE1 and PERK signalling determines the shift from cell survival to apoptosis.
Asunto(s)
Factor de Transcripción Activador 4/metabolismo , Proteínas de Unión al ADN/metabolismo , Estrés del Retículo Endoplásmico/fisiología , Endorribonucleasas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Factores de Transcripción/metabolismo , eIF-2 Quinasa/metabolismo , Apoptosis/fisiología , Línea Celular Tumoral , Supervivencia Celular/fisiología , Humanos , Factores de Transcripción del Factor Regulador X , Transducción de Señal , Análisis de la Célula Individual/métodos , Respuesta de Proteína Desplegada , Proteína 1 de Unión a la X-BoxRESUMEN
UNLABELLED: In locally advanced rectal cancer, neoadjuvant chemoradiotherapy is performed prior to surgery to downstage the tumour. Thirty to 40 % of patients do not respond. Defects in apoptotic machinery lead to therapy resistance; however, to date, no study quantitatively assessed whether B cell lymphoma 2 (BCL2)-dependent regulation of mitochondrial apoptosis, effector caspase activation downstream of mitochondria or a combination of both predicts patient responses. In a cohort of 20 rectal cancer patients, we performed protein profiling of tumour tissue and employed validated ordinary differential equation-based systems models of apoptosis signalling to calculate the ability of cancer cells to undergo apoptosis. Model outputs were compared to clinical responses. Systems modelling of BCL2-signalling predicted patients in the poor response group (p = 0.0049). Systems modelling also demonstrated that rectal cancers depended on BCL2 rather than B cell lymphoma-extra large (BCL(X)L) or myeloid cell leukemia 1 (MCL1) for survival, suggesting that poor responders may benefit from therapy with selective BCL2 antagonists. Dynamic modelling of effector caspase activation could not stratify patients with poor response and did not further improve predictive power. We deliver a powerful patient stratification tool identifying patients who will likely not benefit from neoadjuvant chemoradiotherapy and should be prioritised for surgical resection or treatment with BCL2 antagonists. KEY MESSAGES: Modelling BCL2-family proteins identifies patients unresponsive to therapy. Caspase activation downstream of mitochondria cannot identify these patients. Rectal tumours of poor responders are BCL2- but not BCL-XL-dependent. DR_MOMP allows clinicians to identify patients who would not benefit from therapy. DR_MOMP is also a useful patient stratification tool for BCL2 antagonists.
Asunto(s)
Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Neoplasias del Recto/metabolismo , Adulto , Anciano , Apoptosis , Quimioradioterapia Adyuvante , Daño del ADN , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Membranas Mitocondriales/metabolismo , Poro de Transición de la Permeabilidad Mitocondrial , Terapia Neoadyuvante , Neoplasias del Recto/terapia , Transducción de Señal , Resultado del TratamientoRESUMEN
BACKGROUND: Glioblastoma (GBM), being a highly vascularised and locally invasive tumour, is an attractive target for anti-angiogenic and anti-invasive therapies. The GBM/endothelial cell response to gossypol/temozolomide (TMZ) treatment was investigated with a particular aim to assess treatment effects on cancer hallmarks. METHODS: Cell viability, endothelial tube formation and GBM tumour cell invasion were variously assessed following combined treatment in vitro. The U87MG-luc2 subcutaneous xenograft model was used to investigate therapeutic response in vivo. Viable tumour response to treatment was interrogated using immunohistochemistry. Combined treatment protocols were also tested in primary GBM patient-derived cultures. RESULTS: An endothelial/GBM cell viability inhibitory effect, as well as an anti-angiogenic and anti-invasive response, to combined treatment have been demonstrated in vitro. A significantly greater anti-proliferative (P=0.020, P=0.030), anti-angiogenic (P=0.040, P<0.0001) and pro-apoptotic (P=0.0083, P=0.0149) response was observed when combined treatment was compared with single gossypol/TMZ treatment response, respectively. GBM cell line and patient-specific response to gossypol/TMZ treatment was observed. CONCLUSIONS: Our results indicate that response to a combined gossypol/TMZ treatment is related to inhibition of tumour-associated angiogenesis, invasion and proliferation and warrants further investigation as a novel targeted GBM treatment strategy.
Asunto(s)
Glioblastoma/tratamiento farmacológico , Gosipol/farmacología , Animales , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Femenino , Glioblastoma/patología , Humanos , Ratones , Ratones Endogámicos BALB C , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Stress signaling in response to oxygen/glucose deprivation (OGD) and ischemic injury activates a group of pro-apoptotic genes, the Bcl-2 homology domain 3 (BH3)-only proteins, which are capable of activating the mitochondrial apoptosis pathway. Targeted studies previously identified the BH3-only proteins Puma, Bim and Bid to have a role in ischemic/hypoxic neuronal injury. We here investigated the transcriptional activation of pro-apoptotic BH3-only proteins after OGD-induced injury in murine neocortical neurons. We observed a potent and early upregulation of noxa at mRNA and protein level, and a significant increase in Bmf protein levels during OGD in neocortical neurons and in the ipsilateral cortex of mice subjected to transient middle cerebral artery occlusion (tMCAO). Surprisingly, gene deficiency in noxa reduced neither OGD- nor glutamate-induced neuronal injury in cortical neurons and failed to influence infarct size or neurological deficits after tMCAO. In contrast, bmf deficiency induced significant protection against OGD- or glutamate-induced injury in cultured neurons, and bmf-deficient mice showed reduced neurological deficits after tMCAO in vivo. Collectively, our data not only point to a role of Bmf as a BH3-only protein contributing to excitotoxic and ischemic neuronal injury but also demonstrate that the early and potent induction of noxa does not influence ischemic neuronal injury.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Isquemia Encefálica/metabolismo , Glucosa/metabolismo , Neuronas/metabolismo , Oxígeno/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Apoptosis , Isquemia Encefálica/genética , Isquemia Encefálica/fisiopatología , Células Cultivadas , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/citología , Proteínas Proto-Oncogénicas c-bcl-2/genéticaRESUMEN
Our understanding of the mitochondrial or intrinsic apoptosis pathway and its role in chemotherapy resistance has increased significantly in recent years by a combination of experimental studies and mathematical modelling. This combined approach enhanced the quantitative and kinetic understanding of apoptosis signal transduction, but also provided new insights that systems-emanating functions (i.e., functions that cannot be attributed to individual network components but that are instead established by multi-component interplay) are crucial determinants of cell fate decisions. Among these features are molecular thresholds, cooperative protein functions, feedback loops and functional redundancies that provide systems robustness, and signalling topologies that allow ultrasensitivity or switch-like responses. The successful development of kinetic systems models that recapitulate biological signal transduction observed in living cells have now led to the first translational studies, which have exploited and validated such models in a clinical context. Bottom-up strategies that use pathway models in combination with higher-level modelling at the tissue, organ and whole body-level therefore carry great potential to eventually deliver a new generation of systems-based diagnostic tools that may contribute to the development of personalised and predictive medicine approaches. Here we review major achievements in the systems biology of intrinsic apoptosis signalling, discuss challenges for further model development, perspectives for higher-level integration of apoptosis models and finally discuss requirements for the development of systems medical solutions in the coming years.
Asunto(s)
Apoptosis , Simulación por Computador , Resistencia a Medicamentos , Modelos Biológicos , Biología de Sistemas , Animales , HumanosRESUMEN
Commensal bacteria in the colon may play a role in colorectal cancer (CRC) development. Recent studies from North America showed that Fusobacterium nucleatum (Fn) infection is over-represented in disease tissue versus matched normal tissue in CRC patients. Using quantitative real-time polymerase chain reaction (qPCR) of DNA extracted from colorectal tissue biopsies and surgical resections of three European cohorts totalling 122 CRC patients, we found an over-abundance of Fn in cancerous compared to matched normal tissue (p < 0.0001). To determine whether Fn infection is an early event in CRC development, we assayed Fn in colorectal adenoma (CRA) tissue from 52 Irish patients. While for all CRAs the Fn level was not statistically significantly higher in disease versus normal tissue (p = 0.06), it was significantly higher for high-grade dysplasia (p = 0.015). As a secondary objective, we determined that CRC patients with low Fn levels had a significantly longer overall survival time than patients with moderate and high levels of the bacterium (p = 0.008). The investigation of Fn as a potential non-invasive biomarker for CRC screening showed that, while Fn was more abundant in stool samples from CRC patients compared to adenomas or controls, the levels in stool did not correlate with cancer or adenoma tissue levels from the same individuals. This is the first study examining Fn in the colonic tissue and stool of European CRC and CRA patients, and suggests Fn as a novel risk factor for disease progression from adenoma to cancer, possibly affecting patient survival outcomes. Our results highlight the potential of Fn detection as a diagnostic and prognostic determinant in CRC patients.
Asunto(s)
Adenoma/microbiología , Neoplasias Colorrectales/microbiología , Fusobacterium nucleatum/aislamiento & purificación , Adenoma/genética , Adenoma/mortalidad , Adenoma/patología , Anciano , Anciano de 80 o más Años , Carga Bacteriana , Estudios de Cohortes , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Progresión de la Enfermedad , Heces/microbiología , Femenino , Fusobacterium nucleatum/genética , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Tipificación Molecular , Mutación Missense , Estadificación de Neoplasias , Pronóstico , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas p21(ras) , Proteína p53 Supresora de Tumor/genética , Proteínas ras/genéticaRESUMEN
The N-methyl-D-aspartate (NMDA) receptor, one of the ionotropic glutamate receptor, plays important physiological and pathological roles in learning and memory, neuronal development, acute and chronic neurological diseases, and neurogenesis. This work examines the contribution of the NR2B NMDA receptor subunit to adult neurogenesis/cell proliferation under physiological conditions and following an excitotoxic insult. We have previously shown in vitro that a discrete NMDA-induced, excitotoxic injury to the hippocampus results in an increase in neurogenesis within the dentate gyrus. Here we have characterized adult neurogenesis or proliferation, using BrdU, in an in vivo model of excitotoxic injury to the CA1 subfield of the hippocampus. We demonstrate a peak in neural stem cell proliferation/neurogenesis between 6 and 9 days after the excitotoxic insult. Treatment with ifenprodil, an NR2B subunit-specific NMDA receptor antagonist, without prior injury induction, also increased the number of BrdU-positive cells within the DG and posterior periventricle, indicating that ifenprodil itself could modulate the rate of proliferation. Interestingly, though, the increased level of cell proliferation did not change significantly when ifenprodil was administered following an excitotoxic insult. In conclusion, our results suggest and add to the growing evidence that NR2B subunit-containing NMDA receptors play a role in neural stem cell proliferation.