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Activation of apoptosis in malignant cells is an established strategy for controlling cancer and is potentially curative. To assess the impact of concurrently inducing the extrinsic and intrinsic apoptosis-signaling pathways in acute myeloid leukemia (AML), we evaluated activity of the TRAIL receptor agonistic fusion protein eftozanermin alfa (eftoza; ABBV-621) in combination with the B-cell lymphoma protein-2 selective inhibitor venetoclax in preclinical models and human patients. Simultaneously stimulating intrinsic and extrinsic apoptosis-signaling pathways with venetoclax and eftoza, respectively, enhanced their activities in AML cell lines and patient-derived ex vivo/in vivo models. Eftoza activity alone or plus venetoclax required death receptor 4/5 (DR4/DR5) expression on the plasma membrane but was independent of TP53 or FLT3-ITD status. The safety/tolerability of eftoza as monotherapy and in combination with venetoclax was demonstrated in patients with relapsed/refractory AML in a phase 1 clinical trial. Treatment-related adverse events were reported in 2 of 4 (50%) patients treated with eftoza monotherapy and 18 of 23 (78%) treated with eftoza plus venetoclax. An overall response rate of 30% (7/23; 4 complete responses [CRs], 2 CRs with incomplete hematologic recovery, and 1 morphologic leukemia-free state) was reported in patients who received treatment with eftoza plus venetoclax and 67% (4/6) in patients with myoblasts positive for DR4/DR5 expression; no tumor responses were observed with eftoza monotherapy. These data indicate that combination therapy with eftoza plus venetoclax to simultaneously activate the extrinsic and intrinsic apoptosis-signaling pathways may improve clinical benefit compared with venetoclax monotherapy in relapsed/refractory AML with an acceptable toxicity profile. This trial was registered at www.clinicaltrials.gov as #NCT03082209.
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Antineoplásicos , Leucemia Mieloide Aguda , Humanos , Antineoplásicos/uso terapêutico , Leucemia Mieloide Aguda/patologia , Compostos Bicíclicos Heterocíclicos com Pontes , Sulfonamidas , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêuticoRESUMO
Intracardiac tumors, though uncommon, necessitate a swift and accurate diagnosis for personalized treatment and prognosis estimation. While multi-modality imaging often determines the etiology of these cardiac masses, histological confirmation remains essential for definitive diagnosis and its specific treatment. Since cardiac tumors are often found in high-risk locations (ventricular free wall or atria), precision biopsy is paramount. The least invasive strategy would be to achieve this by means of endomyocardial biopsy (EMB); however real-time additional imaging is essential to reduce the risk of perforation/tamponade and to minimize sampling error. Intracardiac echocardiography (ICE) emerges as an excellent tool to achieve this goal preventing procedural complications and reducing the likelihood of sampling errors obtaining a definitive histopathological diagnosis in all cases. This paper outlines our diagnostic algorithm for optimal patient selection, details three illustrative cases, and elucidates the steps to acquire histopathology via percutaneous transvenous biopsy with ICE guidance in patients with right-sided cardiac tumors. Given the rarity of intracardiac tumors, we advocate these patients be managed by a dedicated multidisciplinary cardio-oncology team including an interventional cardiologist.
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Algoritmos , Neoplasias Cardíacas , Biópsia Guiada por Imagem , Valor Preditivo dos Testes , Ultrassonografia de Intervenção , Humanos , Neoplasias Cardíacas/diagnóstico por imagem , Neoplasias Cardíacas/patologia , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Adulto , EcocardiografiaRESUMO
BACKGROUND: Patients with advanced cancer who no longer have standard treatment options available may decide to participate in early phase clinical trials (i.e. experimental treatments with uncertain outcomes). Shared decision-making (SDM) models help to understand considerations that influence patients' decision. Discussion of patient values is essential to SDM, but such communication is often limited in this context and may require new interventions. The OnVaCT intervention, consisting of a preparatory online value clarification tool (OnVaCT) for patients and communication training for oncologists, was previously developed to support SDM. This study aimed to qualitatively explore associations between patient values that are discussed between patients and oncologists during consultations about potential participation in early phase clinical trials before and after implementation of the OnVaCT intervention. METHODS: This study is part of a prospective multicentre nonrandomized controlled clinical trial and had a between-subjects design: pre-intervention patients received usual care, while post-intervention patients additionally received the OnVaCT. Oncologists participated in the communication training between study phases. Patients' initial consultation on potential early phase clinical trial participation was recorded and transcribed verbatim. Applying a directed approach, two independent coders analysed the transcripts using an initial codebook based on previous studies. Steps of continuous evaluation and revision were repeated until data saturation was reached. RESULTS: Data saturation was reached after 32 patient-oncologist consultations (i.e. 17 pre-intervention and 15 post-intervention). The analysis revealed the values: hope, perseverance, quality or quantity of life, risk tolerance, trust in the healthcare system/professionals, autonomy, social adherence, altruism, corporeality, acceptance of one's fate, and humanity. Patients in the pre-intervention phase tended to express values briefly and spontaneously. Oncologists acknowledged the importance of patients' values, but generally only gave 'contrasting' examples of why some accept and others refuse to participate in trials. In the post-intervention phase, many oncologists referred to the OnVaCT and/or asked follow-up questions, while patients used longer phrases that combined multiple values, sometimes clearly indicating their weighing. CONCLUSIONS: While all values were recognized in both study phases, our results have highlighted the different communication patterns around patient values in SDM for potential early phase clinical trial participation before and after implementation of the OnVaCT intervention. This study therefore provides a first (qualitative) indication that the OnVaCT intervention may support patients and oncologists in discussing their values. TRIAL REGISTRATION: Netherlands Trial Registry: NL7335, registered on July 17, 2018.
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Tomada de Decisões , Neoplasias , Humanos , Estudos Prospectivos , Neoplasias/terapia , Tomada de Decisão Compartilhada , Comunicação , Participação do PacienteRESUMO
BACKGROUND: Patients with advanced cancer for whom standard systemic treatment is no longer available may be offered participation in early phase clinical trials. In the decision making process, both medical-technical information and patient values and preferences are important. Since patients report decisional conflict after deciding on participation in these trials, improving the decision making process is essential. We aim to develop and evaluate an Online Value Clarification Tool (OnVaCT) to assist patients in clarifying their values around this end-of-life decision. This improved sharing of values is hypothesized to support medical oncologists in tailoring their information to individual patients' needs and, consequently, to support patients in taking decisions in line with their values and reduce decisional conflict. METHODS: In the first part, patients' values and preferences and medical oncologists' views hereupon will be explored in interviews and focus groups to build a first prototype OnVaCT using digital communication (serious gaming). Next, we will test feasibility during think aloud sessions, to deliver a ready-to-implement OnVaCT. In the second part, the OnVaCT, with accompanied training module, will be evaluated in a pre-test (12-18 months before implementation) post-test (12-18 months after implementation) study in three major Dutch cancer centres. We will include 276 patients (> 18 years) with advanced cancer for whom standard systemic therapy is no longer available, and who are referred for participation in early phase clinical trials. The first consultation will be recorded to analyse patient-physician communication regarding the discussion of patients' values and the decision making process. Three weeks afterwards, decisional conflict will be measured. DISCUSSION: This project aims to support the discussion of patient values when considering participation in early phase clinical trials. By including patients before their first appointment with the medical oncologist and recording that consultation, we are able to link decisional conflict to the decision making process, e.g. the communication during consultation. The study faces challenges such as timely including patients within the short period between referral and first consultation. Furthermore, with new treatments being developed rapidly, molecular stratification may affect the patient populations included in the pre-test and post-test periods. TRIAL REGISTRATION: Netherlands Trial Registry number: NTR7551 (prospective; July 17, 2018).
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Comportamento de Escolha , Ensaios Clínicos como Assunto/psicologia , Cuidados Paliativos/métodos , Seleção de Pacientes , Relações Médico-Paciente , Ensaios Clínicos como Assunto/métodos , Grupos Focais/métodos , Humanos , Entrevistas como Assunto/métodos , Países Baixos , Cuidados Paliativos/psicologia , Cuidados Paliativos/tendências , Pesquisa QualitativaRESUMO
PURPOSE: Early results from the phase II MEDIOLA study (NCT02734004) in germline BRCA1- and/or BRCA2-mutated (gBRCAm) platinum-sensitive relapsed ovarian cancer (PSROC) showed promising efficacy and safety with olaparib plus durvalumab. We report efficacy and safety of olaparib plus durvalumab in an expansion cohort of women with gBRCAm PSROC (gBRCAm expansion doublet cohort) and two cohorts with non-gBRCAm PSROC, one of which also received bevacizumab (non-gBRCAm doublet and triplet cohorts). PATIENTS AND METHODS: In this open-label, multicenter study, PARP inhibitor-naïve patients received olaparib plus durvalumab treatment until disease progression; the non-gBRCAm triplet cohort also received bevacizumab. Primary endpoints were objective response rate (ORR; gBRCAm expansion doublet cohort), disease control rate (DCR) at 24 weeks (non-gBRCAm cohorts), and safety (all cohorts). RESULTS: The full analysis and safety analysis sets comprised 51, 32, and 31 patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively. ORR was 92.2% [95% confidence interval (CI), 81.1-97.8] in the gBRCAm expansion doublet cohort (primary endpoint); DCR at 24 weeks was 28.1% (90% CI, 15.5-43.9) in the non-gBRCAm doublet cohort (primary endpoint) and 74.2% (90% CI, 58.2-86.5) in the non-gBRCAm triplet cohort (primary endpoint). Grade ≥ 3 adverse events were reported in 47.1%, 65.6%, and 61.3% of patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively, most commonly anemia. CONCLUSIONS: Olaparib plus durvalumab continued to show notable clinical activity in women with gBRCAm PSROC. Olaparib plus durvalumab with bevacizumab demonstrated encouraging clinical activity in women with non-gBRCAm PSROC. No new safety signals were identified.
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Antineoplásicos , Neoplasias Ovarianas , Humanos , Feminino , Bevacizumab/efeitos adversos , Inibidores de Poli(ADP-Ribose) Polimerases/efeitos adversos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Estudos de Coortes , Mutação em Linhagem Germinativa , Antineoplásicos/uso terapêutico , Ftalazinas/efeitos adversos , Carcinoma Epitelial do Ovário/tratamento farmacológico , Recidiva Local de Neoplasia/tratamento farmacológicoRESUMO
KRAS G12C mutation is prevalent in ~4% of colorectal cancer (CRC) and is associated with poor prognosis. Divarasib, a KRAS G12C inhibitor, has shown modest activity as a single agent in KRAS G12C-positive CRC at 400 mg. Epidermal growth factor receptor has been recognized as a major upstream activator of RAS-MAPK signaling, a proposed key mechanism of resistance to KRAS G12C inhibition in CRC. Here, we report on divarasib plus cetuximab (epidermal growth factor receptor inhibitor) in patients with KRAS G12C-positive CRC (n = 29) from arm C of an ongoing phase 1b trial. The primary objective was to evaluate safety. Secondary objectives included preliminary antitumor activity. The safety profile of this combination was consistent with those of single-agent divarasib and cetuximab. Treatment-related adverse events led to divarasib dose reductions in four patients (13.8%); there were no treatment withdrawals. The objective response rate was 62.5% (95% confidence interval: 40.6%, 81.2%) in KRAS G12C inhibitor-naive patients (n = 24). The median duration of response was 6.9 months. The median progression-free survival was 8.1 months (95% confidence interval: 5.5, 12.3). As an exploratory objective, we observed a decline in KRAS G12C variant allele frequency associated with response and identified acquired genomic alterations at disease progression that may be associated with resistance. The manageable safety profile and encouraging antitumor activity of divarasib plus cetuximab support the further investigation of this combination in KRAS G12C-positive CRC.ClinicalTrials.gov identifier: NCT04449874.
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Neoplasias Colorretais , Proteínas Proto-Oncogênicas p21(ras) , Humanos , Cetuximab/efeitos adversos , Cetuximab/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Receptores ErbB/genética , Intervalo Livre de Progressão , Mutação/genéticaRESUMO
PURPOSE: Tissue factor is highly expressed in cervical carcinoma and can be targeted by tisotumab vedotin (TV), an antibody-drug conjugate. This phase Ib/II study evaluated TV in combination with bevacizumab, pembrolizumab, or carboplatin for recurrent or metastatic cervical cancer (r/mCC). METHODS: This open-label, multicenter study (ClinicalTrials.gov identifier: NCT03786081) included dose-escalation arms that assessed dose-limiting toxicities (DLTs) and identified the recommended phase II dose (RP2D) of TV in combination with bevacizumab (arm A), pembrolizumab (arm B), or carboplatin (arm C). The dose-expansion arms evaluated TV antitumor activity and safety at RP2D in combination with carboplatin as first-line (1L) treatment (arm D) or with pembrolizumab as 1L (arm E) or second-/third-line (2L/3L) treatment (arm F). The primary end point of dose expansion was objective response rate (ORR). RESULTS: A total of 142 patients were enrolled. In dose escalation (n = 41), no DLTs were observed; the RP2D was TV 2 mg/kg plus bevacizumab 15 mg/kg on day 1 once every 3 weeks, pembrolizumab 200 mg on day 1 once every 3 weeks, or carboplatin AUC 5 on day 1 once every 3 weeks. In dose expansion (n = 101), the ORR was 54.5% (n/N, 18/33; 95% CI, 36.4 to 71.9) with 1L TV + carboplatin (arm D), 40.6% (n/N, 13/32; 95% CI, 23.7 to 59.4) with 1L TV + pembrolizumab (arm E), and 35.3% (12/34; 19.7 to 53.5) with 2L/3L TV + pembrolizumab (arm F). The median duration of response was 8.6 months, not reached, and 14.1 months, in arms D, E, and F, respectively. Grade ≥3 adverse events (≥15%) were anemia, diarrhea, nausea, and thrombocytopenia in arm D and anemia in arm F (none ≥15%, arm E). CONCLUSION: TV in combination with bevacizumab, carboplatin, or pembrolizumab demonstrated manageable safety and encouraging antitumor activity in treatment-naive and previously treated r/mCC.
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Anemia , Neoplasias Pulmonares , Neoplasias do Colo do Útero , Feminino , Humanos , Bevacizumab/efeitos adversos , Carboplatina/efeitos adversos , Neoplasias do Colo do Útero/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Recidiva Local de Neoplasia/etiologia , Neoplasias Pulmonares/tratamento farmacológico , Anemia/tratamento farmacológicoRESUMO
When standard treatment options are not available anymore, patients with advanced cancer may participate in early phase clinical trials. Improving this complex decision-making process may improve their quality of life. Therefore, this prospective multicenter study with questionnaires untangles several contributing factors to decisional conflict (which reflects the quality of decision-making) in patients with advanced cancer who recently decided upon early phase clinical trial participation (phase I or I/II). We hypothesized that health-related quality of life, health literacy, sense of hope, satisfaction with the consultation, timing of the decision, and the decision explain decisional conflict. Mean decisional conflict in 116 patients was 30.0 (SD = 16.9). Multivariate regression analysis showed that less decisional conflict was reported by patients with better global health status (ß = −0.185, p = 0.018), higher satisfaction (ß = −0.246, p = 0.002), and who made the decision before (ß = −0.543, p < 0.001) or within a week after the consultation (ß = −0.427, p < 0.001). These variables explained 37% of the variance in decisional conflict. Healthcare professionals should realize that patients with lower global health status and who need more time to decide may require additional support. Although altering such patient intrinsic characteristics is difficult, oncologists can impact the satisfaction with the consultation. Future research should verify whether effective patient-centered communication could prevent decisional conflict.
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PURPOSE: Patients with rare cancers (incidence less than 6 cases per 100,000 persons per year) commonly have less treatment opportunities and are understudied at the level of genomic targets. We hypothesized that patients with rare cancer benefit from approved anticancer drugs outside their label similar to common cancers. EXPERIMENTAL DESIGN: In the Drug Rediscovery Protocol (DRUP), patients with therapy-refractory metastatic cancers harboring an actionable molecular profile are matched to FDA/European Medicines Agency-approved targeted therapy or immunotherapy. Patients are enrolled in parallel cohorts based on the histologic tumor type, molecular profile and study drug. Primary endpoint is clinical benefit (complete response, partial response, stable disease ≥ 16 weeks). RESULTS: Of 1,145 submitted cases, 500 patients, including 164 patients with rare cancers, started one of the 25 available drugs and were evaluable for treatment outcome. The overall clinical benefit rate was 33% in both the rare cancer and nonrare cancer subgroup. Inactivating alterations of CDKN2A and activating BRAF aberrations were overrepresented in patients with rare cancer compared with nonrare cancers, resulting in more matches to CDK4/6 inhibitors (14% vs. 4%; P ≤ 0.001) or BRAF inhibitors (9% vs. 1%; P ≤ 0.001). Patients with rare cancer treated with small-molecule inhibitors targeting BRAF experienced higher rates of clinical benefit (75%) than the nonrare cancer subgroup. CONCLUSIONS: Comprehensive molecular testing in patients with rare cancers may identify treatment opportunities and clinical benefit similar to patients with common cancers. Our findings highlight the importance of access to broad molecular diagnostics to ensure equal treatment opportunities for all patients with cancer.
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Neoplasias , Proteínas Proto-Oncogênicas B-raf , Genômica/métodos , Humanos , Terapia de Alvo Molecular/métodos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Medicina de Precisão , Proteínas Proto-Oncogênicas B-raf/genéticaRESUMO
Metastases formation is a major factor in disease progression and accounts for the majority of cancer deaths. The molecular mechanisms controlling invasion, dissemination to blood or lymphatic systems and spread of tumor cells to distant organs are still poorly understood. Recent observations indicate that the meta-static phenotype may already be present during the angiogenic switch of tumors. Intratumoral hypoxia correlates with poor prognosis and enhanced metastases formation. The Hypoxia Inducible Factors (HIFs) are key molecules in the hypoxic response and play critical roles during tumor cell expansion by regulating energy metabolism and the induction of angiogenesis. Increasing evidence implicates HIF function in metastatic cell characteristics, like epithelial to mesenchymal transition, cell detachment, invasion and tumor cell seeding. Here, we review the link between tumor cell hypoxia and the acquisition of metastatic behavior. We hypothesize that polyclonal tumor selection by hypoxia enhances metastatic capacity by transcriptional control of key regulators of metastasis. This polyclonal hypoxic gene profile potentially develops into a metastatic profile, driving metastasis formation. The hypoxic gene profile in primary tumors may therefore provide a prognostic indicator in clinical decision-making.
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Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Hipóxia/metabolismo , Metástase Neoplásica , Neoplasias , Acidose , Anoikis , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Humanos , Invasividade Neoplásica , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologiaRESUMO
Cancer therapy-related cardiac dysfunction (CTRCD) is one of the most concerning cardiovascular side effects of cancer treatment. Important reviews within the field of cardio-oncology have described various agents to be associated with a high risk of CTRCD, including mitomycin C, ifosfamide, vincristine, cyclophosphamide, and clofarabine. The aim of this study was to provide insight into the data on which these incidence rates are based. We observed that the reported cardiotoxicity of mitomycin C and ifosfamide is based on studies in which most patients received anthracyclines, complicating the interpretation of their association with CTRCD. The high incidence of vincristine-induced cardiotoxicity is based on an incorrect interpretation of a single study. Incidence rates of clofarabine remain uncertain due to a lack of cardiac screening in clinical trials. The administration of high-dose cyclophosphamide (>1.5 g/m2/day) is associated with a high incidence of CTRCD. Based on our findings, a critical re-evaluation of the cardiotoxicity of these agents is warranted.
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TWIST1, an antiapoptotic and prometastatic transcription factor, is overexpressed in many epithelial cancers including breast. Only little is known regarding the regulation of TWIST1 in these cancers. Recently, an increase in the TWIST1 promoter methylation has been shown in breast cancers. To correlate the percentage of TWIST1 promoter methylation to the protein levels, we analyzed simultaneously the methylation status as well as the mRNA and the percentage of cells expressing TWIST1 in normal breast tissue and 76 invasive breast cancers. We found that TWIST1 promoter methylation is significantly more prevalent in malignant compared with healthy breast tissue. Furthermore, the percentage of cells expressing TWIST1 was greater in breast malignancy compared with matched healthy tissue from the same patients. There was no correlation, however, between TWIST1 promoter methylation and TWIST1 protein or RNA expression. This indicates that although TWIST1 CpG methylation is useful as a biomarker in breast cancer diagnosis, there is no direct correlation with TWIST1 expression.
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Neoplasias da Mama/genética , Metilação de DNA , Proteínas Nucleares/genética , Proteína 1 Relacionada a Twist/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/análise , Mama/metabolismo , Mama/patologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Distribuição de Qui-Quadrado , Expressão Gênica , Humanos , Immunoblotting , Técnicas Imunoenzimáticas , Pessoa de Meia-Idade , Invasividade Neoplásica , Reação em Cadeia da Polimerase/métodos , Regiões Promotoras Genéticas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estatísticas não ParamétricasRESUMO
Hypoxia is a hallmark of solid cancers and triggers the transcription of genes responsible for cell survival. The transcription factor Hypoxia-Inducible Factor 1 (HIF-1) is a key regulator in this response and frequently activated in human cancer. HIF-1 activation is associated with tumor aggressiveness and poor clinical outcome and, therefore, may provide an attractive therapeutic target. Here we provide a novel approach for HIF-1 targeted therapy using single-domain llama antibodies directed against the HIF-1alpha oxygen dependent degradation domain which encompass the N-terminal transactivation domain. Conditional expression of HIF intrabodies in mammalian cells interfered with binding to pVHL and inhibited hypoxia induced activation of endogenous target genes. Inducible intrabody targeting is a highly specific strategy for temporal protein inactivation and may have applications for disease treatment.
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Especificidade de Anticorpos , Subunidade alfa do Fator 1 Induzível por Hipóxia/imunologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Fragmentos de Imunoglobulinas/imunologia , Animais , Afinidade de Anticorpos , Western Blotting , Camelídeos Americanos , Linhagem Celular Tumoral , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Imunoprecipitação , Regiões Promotoras Genéticas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica , TransfecçãoRESUMO
Reverse genetic or gene-driven knockout approaches have contributed significantly to the success of model organisms for fundamental and biomedical research. Although various technologies are available for C. elegans, none of them scale very well for genome-wide application. To address this, we implemented a target-selected knockout approach that is based on random chemical mutagenesis and detection of single nucleotide mutations in genes of interest using high-throughput resequencing. A clonal library of 6144 EMS-mutagenized worms was established and screened, resulting in the identification of 1044 induced mutations in 109 Mbp, which translates into an average spacing between exonic mutations in the library of only 17 bp. We covered 25% of the open reading frames of 32 genes and identified one or more inactivating mutations (nonsense or splice site) in 84% of them. Extrapolation of our results indicates that nonsense mutations for >90% of all C. elegans genes are present in the library. To identify all of these mutations, one only needs to inspect those positions that--given the known specificity of the mutagen--can result in the introduction of a stop codon. We define these positions as nonsense introducing mutations (NIMs). The genome-wide collection of possible NIMs can be calculated for any organism with a sequenced genome and reduces the screening complexity by 200- to 2000-fold, depending on the organism and mutagen. For EMS-mutagenized C. elegans, there are only approximately 500,000 NIMs. We show that a NIM genotyping approach employing high-density microarrays can, in principle, be used for the genome-wide identification of C. elegans knockouts.
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Animais Geneticamente Modificados , Caenorhabditis elegans/genética , Marcação de Genes , Biblioteca Genômica , Mutagênese Sítio-Dirigida , Animais , Sequência de Bases , Frequência do Gene/genética , Genoma Helmíntico/genética , Dados de Sequência MolecularRESUMO
Hypoxia triggers the transcription of genes responsible for cell survival via the key player transcription factor hypoxia-inducible factor 1alpha (HIF-1alpha). Overexpression of this protein has been implicated in cardiovascular disorders, carcinogenesis and cancer progression. For functional and diagnostic studies on the HIF-1alpha protein, we have identified single-domain antibody fragments directed against this protein by using a llama-derived nonimmune phage display library. This library displays the variable domains of the heavy-chain antibody subclass, found in these animals. Phage display selection with six recombinant HIF-1alpha proteins yielded five different antibody fragments. By epitope-mapping, we show that all five antibody fragments bind within the functionally important oxygen-dependent degradation domain of the HIF-1alpha protein. Two of these antibody fragments were engineered into bivalent antibodies that were able to detect human HIF-1alpha by immunohistochemistry, Western blotting and immunoprecipitation, and mouse HIF-1alpha by immunofluorescence and immunoprecipitation. These are the first single-domain antibody fragments that may be used in exploration of HIF-1alpha as a possible therapeutic target through molecular applications.