Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
N Engl J Med ; 389(10): 911-921, 2023 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-37672694

RESUMO

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare soft-tissue sarcoma with a poor prognosis and no established therapy. Recently, encouraging responses to immune checkpoint inhibitors have been reported. METHODS: We conducted an investigator-initiated, multicenter, single-group, phase 2 study of the anti-programmed death ligand 1 (PD-L1) agent atezolizumab in adult and pediatric patients with advanced ASPS. Atezolizumab was administered intravenously at a dose of 1200 mg (in patients ≥18 years of age) or 15 mg per kilogram of body weight with a 1200-mg cap (in patients <18 years of age) once every 21 days. Study end points included objective response, duration of response, and progression-free survival according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, as well as pharmacodynamic biomarkers of multistep drug action. RESULTS: A total of 52 patients were evaluated. An objective response was observed in 19 of 52 patients (37%), with 1 complete response and 18 partial responses. The median time to response was 3.6 months (range, 2.1 to 19.1), the median duration of response was 24.7 months (range, 4.1 to 55.8), and the median progression-free survival was 20.8 months. Seven patients took a treatment break after 2 years of treatment, and their responses were maintained through the data-cutoff date. No treatment-related grade 4 or 5 adverse events were recorded. Responses were noted despite variable baseline expression of programmed death 1 and PD-L1. CONCLUSIONS: Atezolizumab was effective at inducing sustained responses in approximately one third of patients with advanced ASPS. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT03141684.).


Assuntos
Anticorpos Monoclonais Humanizados , Antígeno B7-H1 , Sarcoma Alveolar de Partes Moles , Adolescente , Adulto , Criança , Humanos , Recém-Nascido , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/uso terapêutico , Antígeno B7-H1/antagonistas & inibidores , Peso Corporal , Sarcoma Alveolar de Partes Moles/tratamento farmacológico , Administração Intravenosa
2.
J Biol Chem ; 298(12): 102690, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36372232

RESUMO

RNA Polymerase I (Pol I) synthesizes rRNA, which is the first and rate-limiting step in ribosome biogenesis. Factors governing the stability of the polymerase complex are not known. Previous studies characterizing Pol I inhibitor BMH-21 revealed a transcriptional stress-dependent pathway for degradation of the largest subunit of Pol I, RPA194. To identify the E3 ligase(s) involved, we conducted a cell-based RNAi screen for ubiquitin pathway genes. We establish Skp-Cullin-F-box protein complex F-box protein FBXL14 as an E3 ligase for RPA194. We show that FBXL14 binds to RPA194 and mediates RPA194 ubiquitination and degradation in cancer cells treated with BMH-21. Mutation analysis in yeast identified lysines 1150, 1153, and 1156 on Rpa190 relevant for the protein degradation. These results reveal the regulated turnover of Pol I, showing that the stability of the catalytic subunit is controlled by the F-box protein FBXL14 in response to transcription stress.


Assuntos
Proteínas F-Box , Proteínas Ligases SKP Culina F-Box , Transcrição Gênica , Domínio Catalítico , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , RNA Polimerase I/genética , RNA Polimerase I/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Ligases SKP Culina F-Box/genética , Proteínas Ligases SKP Culina F-Box/metabolismo , Ubiquitinação , Humanos , Transcrição Gênica/genética
3.
Br J Cancer ; 122(4): 498-505, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31857726

RESUMO

BACKGROUND: The Hedgehog (Hh) signalling pathway is overexpressed in pancreatic ductal adenocarcinoma (PDA). Preclinical studies have shown that Hh inhibitors reduce pancreatic cancer stem cells (pCSC), stroma and Hh signalling. METHODS: Patients with previously untreated metastatic PDA were treated with gemcitabine and nab-paclitaxel. Vismodegib was added starting on the second cycle. The primary endpoint was progression-free survival (PFS) as compared with historical controls. Tumour biopsies to assess pCSC, stroma and Hh signalling were obtained before treatment and after cycle 1 (gemcitabine and nab-paclitaxel) or after cycle 2 (gemcitabine and nab-paclitaxel plus vismodegib). RESULTS: Seventy-one patients were enrolled. Median PFS and overall survival (OS) were 5.42 months (95% confidence interval [CI]: 4.37-6.97) and 9.79 months (95% CI: 7.85-10.97), respectively. Of the 67 patients evaluable for response, 27 (40%) had a response: 26 (38.8%) partial responses and 1 complete response. In the tumour samples, there were no significant changes in ALDH + pCSC following treatment. CONCLUSIONS: Adding vismodegib to chemotherapy did not improve efficacy as compared with historical rates observed with chemotherapy alone in patients with newly diagnosed metastatic pancreatic cancer. This study does not support the further evaluation of Hh inhibitors in this patient population. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01088815.


Assuntos
Anilidas/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Ductal Pancreático/tratamento farmacológico , Neoplasias Pancreáticas/tratamento farmacológico , Piridinas/administração & dosagem , Idoso , Albuminas/administração & dosagem , Albuminas/efeitos adversos , Anilidas/efeitos adversos , Carcinoma Ductal Pancreático/mortalidade , Carcinoma Ductal Pancreático/secundário , Desoxicitidina/administração & dosagem , Desoxicitidina/efeitos adversos , Desoxicitidina/análogos & derivados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem , Paclitaxel/efeitos adversos , Neoplasias Pancreáticas/mortalidade , Intervalo Livre de Progressão , Piridinas/efeitos adversos , Resultado do Tratamento , Gencitabina , Neoplasias Pancreáticas
4.
Int J Cancer ; 143(1): 113-126, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29396848

RESUMO

Chronic arsenic exposure is associated with the development of urothelial carcinoma of the bladder (UCB). To elucidate the contribution of arsenic exposure to urothelial cancer stem cell (CSC) generation, we established an in vitro stepwise malignant model transformed by chronically exposing human urothelial cells to arsenic. Using this model, we found that chronic arsenic exposure endows urothelial cells with malignant stemness properties including increased expression of stemness-related factors such as SOX2, sphere formation, self-renewal, invasion and chemoresistance. SOX2 was gradually and irreversibly overexpressed in line with acquired sphere-forming and self-renewal abilities. Following gene set enrichment analyses of arsenic-exposed and arsenic-unexposed cells, we found COX2 as an enriched gene for oncogenic signature. Mechanistically, arsenic-induced COX2/PGE2 increases SOX2 expression that eventually promotes malignant stem cell generation and repopulation. In urine samples from 90 subjects exposed to arsenic and 91 control subjects, we found a significant linear correlation between SOX2 and COX2 expression and the potential of SOX2 and COX2 expression as urinary markers to detect subjects exposed to arsenic. Furthermore, the combination marker yielded a high sensitivity for UCB detection in a separate cohort. Finally, our in vitro model exhibits basal-type molecular features and dual inhibition of EGFR and COX2 attenuated stem cell enrichment more efficiently than an EGFR inhibitor alone. In conclusion, the COX2/PGE2-SOX2 axis promotes arsenic-induced malignant stem cell transformation. In addition, our findings indicate the possible use of SOX2 and COX2 expression as urinary markers for the risk stratification and detection of UCB.


Assuntos
Arsênio/toxicidade , Transformação Celular Neoplásica/induzido quimicamente , Ciclo-Oxigenase 2/genética , Dinoprostona/metabolismo , Fatores de Transcrição SOXB1/genética , Urotélio/citologia , Biomarcadores Tumorais/urina , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Ciclo-Oxigenase 2/metabolismo , Ciclo-Oxigenase 2/urina , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Fatores de Transcrição SOXB1/metabolismo , Fatores de Transcrição SOXB1/urina , Regulação para Cima , Urotélio/efeitos dos fármacos , Urotélio/metabolismo
5.
J Chemother ; : 1-15, 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-39282901

RESUMO

Better in vitro models are needed to identify active drugs to treat pancreatic adenocarcinoma (PAC) patients. We used 3D hanging drop cultures to produce spheroids from five PAC cell lines and tested nine FDA-approved drugs in clinical use. All PAC cell lines in 2D culture were sensitive to three drugs (gemcitabine, docetaxel and nab-paclitaxel), however most PAC (4/5) 3D spheroids acquired profound chemoresistance even at 10 µM. In contrast, spheroids retained sensitivity to the investigational drug triptolide, which induced apoptosis. The acquired chemoresistance was also transiently retained when cells were placed back into 2D culture and six genes potentially associated with chemoresistance were identified by microarray and confirmed using quantitative RT-PCR. We demonstrate the additive effect of gemcitabine and erlotinib, from the 12 different combinations of nine drugs tested. This comprehensive study shows spheroids as a useful multicellular model of PAC for drug screening and elucidating the mechanism of chemoresistance.

6.
bioRxiv ; 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39211199

RESUMO

Ribosome biosynthesis is a cancer vulnerability executed by targeting RNA polymerase I (Pol I) transcription. We developed advanced, specific Pol I inhibitors to identify drivers of this sensitivity. By integrating multi-omics features and drug sensitivity data from a large cancer cell panel, we discovered that RPL22 frameshift mutation conferred Pol I inhibitor sensitivity in microsatellite instable cancers. Mechanistically, RPL22 directly interacts with 28S rRNA and mRNA splice junctions, functioning as a splicing regulator. RPL22 deficiency, intensified by 28S rRNA sequestration, promoted the splicing of its paralog RPL22L1 and p53 negative regulator MDM4. Chemical and genetic inhibition of rRNA synthesis broadly remodeled mRNA splicing controlling hundreds of targets. Strikingly, RPL22-dependent alternative splicing was reversed by Pol I inhibition revealing a ribotoxic stress-initiated tumor suppressive pathway. We identify a mechanism that robustly connects rRNA synthesis activity to splicing and reveals their coordination by ribosomal protein RPL22.

7.
Curr Diabetes Rev ; 18(9): e190122200353, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35043763

RESUMO

BACKGROUND: The rate of mortality is increasing in diabetic patients due to diabetes-associated complications. The common complications include neuropathy, nephropathy, retinopathy, foot ulcer, slow wound healing, kidney dysfunction, amputation, dysfunction of organs, frequent infections, sepsis, skin diseases, hearing impairment, cardiovascular disorders, etc. These complications can be diagnosed following some common symptoms such as increased thirst, frequent urination, extreme hunger, unexplained weight loss, fatigue, irritability, blurred vision, slow-healing sores, etc. This survey was designed to study the prevalence of various complications in a group of diabetic patients so that effective treatment options could be developed against the most prevalent complications. METHODS: This cross-sectional study was conducted in 2019 in a tertiary care hospital of Karachi after the approval of the ethical committee of the hospital as well as in the University of Karachi. To perform this study, a questionnaire was designed comprised of different questions related to diabetic complications. The consent form was attached to each questionnaire in which the patient agreed to participate voluntarily in this survey. The diabetic patients who visited the General Physician OPD were the subjects of this survey. All designed questions included in the questionnaire were asked either directly from the patients or their attendants. RESULTS: A total of 160 diabetic subjects were part of the study range between the ages of 11 to 90 years. Out of 160 patients, 52 were males, and 108 were females. Among all subjects, 124 (78 %) patients were type 2 while 57 (36 %) were type 1 diabetic patients. 117 (73 %) showed confusion of mind, 104 (65 %) complained of blood pressure, 105 (66 %) had hypertension, 106 (66 %) had eye damage (retinopathy), 96 (60 %) were facing trouble focusing vision, and 70 (44 %) were experiencing seizures, 63 (39 %) patients had laser treatment, 68 (43 %) showed wounds on foot and slow wounds healing, 49 (31 %) were having kidney damage (nephropathy), 79 (49 %) had pain in legs or knee, 35 (22 %) and 26 (16 %) complained of heart problems and liver damage respectively. Some patients were found to deal with more hunger, i.e., 99 (62 %) patients, 118 (74 %) were experiencing frequent urine desire, 138 (86 %) showed fatigue, 123 (77 %) complained of thirst, 35 (22 %) had nausea, 30 (19 %) had a frequent cold, 36 (23 %) had skin problems, 17 (11 %) patients showed frequent vomiting, 19 (12 %), 13 (8 %) and 16 (10 %) were experiencing acne formation, stroke and nerve damage (neuropathy) respectively. CONCLUSION: All age groups showed diabetes-associated complications and different abnormal body conditions. However, the age groups ranging from thirty to eighty years showed more complications. The most prevalent complications reported were retinopathy, nephropathy, diabetic wounds on the foot, slow wound healing, seizures, hypertension, neuropathy, skin infections, cardiovascular disorders, liver damage, and stroke in both types of diabetic patients. Our survey may aid in pointing out the most prevalent diabetic complications prevailing in our population so that effective treatment options could be developed to reduce these life-threatening complications.


Assuntos
Doenças Cardiovasculares , Complicações do Diabetes , Diabetes Mellitus Tipo 2 , Hipertensão , Doenças Retinianas , Acidente Vascular Cerebral , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/epidemiologia , Criança , Estudos Transversais , Complicações do Diabetes/complicações , Complicações do Diabetes/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Fadiga/complicações , Feminino , Humanos , Hipertensão/complicações , Masculino , Pessoa de Meia-Idade , Paquistão/epidemiologia , Prevalência , Convulsões/complicações , Acidente Vascular Cerebral/complicações , Inquéritos e Questionários , Adulto Jovem
8.
ACS Med Chem Lett ; 13(4): 608-614, 2022 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-35450366

RESUMO

RNA polymerase I (Pol I) transcribes ribosomal DNA (rDNA) into the 47S ribosomal RNA (rRNA) precursor. Further processing produces the 28S, 5.8S, and 18S rRNAs that are assembled into mature ribosomes. Many cancers exhibit higher Pol I transcriptional activity, reflecting a need for increased ribosome biogenesis and protein synthesis and making the inhibition of this process an attractive therapeutic strategy. Lead molecule BMH-21 (1) has been established as a Pol I inhibitor by affecting the destruction of RPA194, the Pol I large catalytic subunit. A previous structure-activity relationship (SAR) study uncovered key pharmacophores, but activity was constrained within a tight chemical space. This work details further SAR efforts that have yielded new scaffolds and improved off-target activity while retaining the desired RPA194 degradation potency. Pharmacokinetic profiling was obtained and provides a starting point for further optimization. New compounds present additional opportunities for the development of Pol I inhibitory cancer therapies.

9.
Bull World Health Organ ; 88(8): 584-92, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20680123

RESUMO

OBJECTIVE: To develop a simple tool for assessing the severity of disability resulting from Japanese encephalitis and whether, as a result, a child is likely to be dependent. METHODS: A new outcome score based on a 15-item questionnaire was developed after a literature review, examination of current assessment tools, discussion with experts and a pilot study. The score was used to evaluate 100 children in Malaysia (56 Japanese encephalitis patients, 2 patients with encephalitis of unknown etiology and 42 controls) and 95 in India (36 Japanese encephalitis patients, 41 patients with encephalitis of unknown etiology and 18 controls). Inter- and intra-observer variability in the outcome score was determined and the score was compared with full clinical assessment. FINDINGS: There was good inter-observer agreement on using the new score to identify likely dependency (Kappa = 0.942 for Malaysian children; Kappa = 0.786 for Indian children) and good intra-observer agreement (Kappa = 1.000 and 0.902, respectively). In addition, agreement between the new score and clinical assessment was also good (Kappa = 0.906 and 0.762, respectively). The sensitivity and specificity of the new score for identifying children likely to be dependent were 100% and 98.4% in Malaysia and 100% and 93.8% in India. Positive and negative predictive values were 84.2% and 100% in Malaysia and 65.6% and 100% in India. CONCLUSION: The new tool for assessing disability in children after Japanese encephalitis was simple to use and scores correlated well with clinical assessment.


Assuntos
Avaliação da Deficiência , Pessoas com Deficiência , Encefalite/fisiopatologia , Inquéritos e Questionários/normas , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Índia , Malásia , Masculino , Projetos Piloto , Índice de Gravidade de Doença
10.
Cancer Sci ; 100(10): 1908-16, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19594544

RESUMO

Amplification of chromosomal DNA is thought to be one of the mechanisms activating cancer-related genes in tumors. To identify the most likely target for amplification in the region 19q13.12-q13.2, detected previously in SKN-3 cells by a genome-wide screening of DNA copy-number aberrations in a panel of oral squamous-cell carcinoma (OSCC) cell lines, we determined the extent of the amplicon, analyzed a panel of cell lines for the expression of candidate genes within the amplicon, and then evaluated growth-suppressive effects by knocking down genes of interest. Reported information about the function and/or expression of each gene, remarkable overexpression in SKN-3 cells and relatively frequent overexpression in additional OSCC lines compared with an immortalized normal oral epithelial cell line, and expression level-dependent proliferation-promoting activity led us to conclude that the p21-activated kinase 4 (PAK4) gene was the most likely target. An immunohistochemical analysis of primary tumors from 105 cases of head and neck SCC including 50 cases of OSCC demonstrated the overexpression of PAK4 to be significantly associated with a poorer prognosis. These findings reveal that the PAK4 overexpression through amplification or other mechanisms promotes the proliferation and/or survival of OSCC cells, and that PAK4 might be a good diagnostic and/or therapeutic target.


Assuntos
Carcinoma de Células Escamosas/genética , Cromossomos Humanos Par 19/genética , Amplificação de Genes , Regulação Neoplásica da Expressão Gênica , Neoplasias Bucais/genética , Quinases Ativadas por p21/genética , Biomarcadores Tumorais/genética , Western Blotting , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Análise Mutacional de DNA , Feminino , Dosagem de Genes , Humanos , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/patologia , Estadiamento de Neoplasias , Prognóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa
11.
Pancreas ; 48(1): 94-98, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30540680

RESUMO

OBJECTIVES: IQ motif containing GTPase-activating protein 1 (IQGAP1) acts as a scaffold for aberrant mitogen-activated protein kinase (MAPK) signaling driven by KRAS mutations in pancreatic ductal adenocarcinoma (PDAC). We determined the role of IQGAP1 in clonogenic growth and metastasis in PDAC. METHODS: We inhibited IQGAP1 expression using shRNA and assessed clonogenic growth, cell migration, and MAPK signaling in vitro and tumor initiation and metastasis in vivo. The efficacy of a peptide mimicking the IQGAP1 WW domain that binds and inhibits ERK1/2 was determined in vitro and in vivo. RESULTS: IQGAP1 loss inhibited clonogenic growth and migration of KRAS-dependent PDAC cells by disrupting MAPK signaling. In mice, IQGAP1 knockdown decreased tumor-initiating cell frequency and metastasis. WW peptide treatment inhibited clonogenic growth and in vivo tumor growth. CONCLUSIONS: Pancreatic ductal adenocarcinoma clonogenic growth, metastasis, and tumor initiation are dependent on MAPK signaling via IQGAP1. Treatment with a WW peptide disrupts IQGAP1 function and represents a novel targeting strategy for PDAC.


Assuntos
Carcinoma Ductal Pancreático/genética , Neoplasias Pancreáticas/genética , Proteínas Ativadoras de ras GTPase/genética , Animais , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/terapia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Humanos , Sistema de Sinalização das MAP Quinases/genética , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Metástase Neoplásica , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/terapia , Interferência de RNA , Terapêutica com RNAi/métodos , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Proteínas Ativadoras de ras GTPase/metabolismo
12.
Pancreas ; 48(3): 329-334, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30747824

RESUMO

OBJECTIVE: Cancer-associated fibroblasts (CAFs) play an important role in the progression of pancreatic ductal adenocarcinoma (PDAC) by promoting tumor cell migration and drug resistance. We determined the impact of CAFs on PDAC cancer stem cells (CSCs). METHODS: Fibroblast cell lines from patients' tumors were cocultured with PDAC cells and examined for clonogenic growth and self-renewal using colony-forming assays and migration in vitro. Changes in the frequency of CSCs was determined by flow cytometry. The effect of integrin-focal adhesion kinase (FAK) signaling on CAF-mediated clonogenic growth was evaluated using short hairpin RNAs against ß1 integrin and FAK as well as a small-molecule FAK inhibitor. RESULTS: Cancer-associated fibroblasts enhanced PDAC clonogenic growth, self-renewal, and migration that was associated with an increase in the frequency of CSCs. These fibroblast cells were activated by PDAC cells and increased collagen synthesis resulting in FAK activation in PDAC cells. Knockdown of ß1-integrin and FAK or the inhibition of FAK kinase activity in PDAC cells abrogated the impact of CAFs on clonogenic growth. CONCLUSION: Therefore, CAFs enhance PDAC clonogenic growth, self-renewal, and the frequency of CSCs through type I collagen production that enhances integrin-FAK signaling in PDAC cells.


Assuntos
Fibroblastos Associados a Câncer/patologia , Comunicação Celular , Células-Tronco Neoplásicas/patologia , Neoplasias Pancreáticas/patologia , Fibroblastos Associados a Câncer/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Células Cultivadas , Técnicas de Cocultura , Quinase 1 de Adesão Focal/genética , Quinase 1 de Adesão Focal/metabolismo , Humanos , Integrina beta1/genética , Integrina beta1/metabolismo , Células-Tronco Neoplásicas/metabolismo , Neoplasias Pancreáticas/metabolismo , Interferência de RNA , Transdução de Sinais/genética
13.
Mol Cancer Res ; 17(4): 929-936, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30655325

RESUMO

Self-renewal maintains the long-term clonogenic growth that is required for cancer relapse and progression, but the cellular processes regulating this property are not fully understood. In many diseases, self-renewal is enhanced in cancer stem cells (CSC), and in pancreatic ductal adenocarcinoma (PDAC), CSCs are characterized by the surface expression of CD44. In addition to cell adhesion, CD44 impacts cell shape and morphology by modulating the actin cytoskeleton via Ezrin, a member of the Ezrin/Radixin/Moesin (ERM) family of linker proteins. We examined the expression of Ezrin in PDAC cells and found higher levels of both total and activated Ezrin in CSCs compared with bulk tumor cells. We also found that the knockdown of Ezrin in PDAC cells decreased clonogenic growth, self-renewal, cell migration, and CSC frequency in vitro as well as tumor initiation in vivo. These effects were associated with cytoskeletal changes that are similar to those occurring during the differentiation of normal stem cells, and the inhibition of actin remodeling reversed the impact of Ezrin loss. Finally, targeting Ezrin using a small-molecule inhibitor limited the self-renewal of clinically derived low-passage PDAC xenografts. Our findings demonstrate that Ezrin modulates CSCs properties and may represent a novel target for the treatment of PDAC. IMPLICATIONS: Our findings demonstrate that Ezrin modulates CSCs' properties and may represent a novel target for the treatment of PDAC.


Assuntos
Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Proteínas do Citoesqueleto/biossíntese , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Actinas/metabolismo , Adamantano/análogos & derivados , Adamantano/farmacologia , Animais , Linhagem Celular Tumoral , Proteínas do Citoesqueleto/antagonistas & inibidores , Proteínas do Citoesqueleto/metabolismo , Xenoenxertos , Humanos , Camundongos , Camundongos Nus , Quinolinas/farmacologia
14.
Cancer Res ; 78(1): 168-181, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29180467

RESUMO

Overcoming acquired drug resistance remains a core challenge in the clinical management of human cancer, including in urothelial carcinoma of the bladder (UCB). Cancer stem-like cells (CSC) have been implicated in the emergence of drug resistance but mechanisms and intervention points are not completely understood. Here, we report that the proinflammatory COX2/PGE2 pathway and the YAP1 growth-regulatory pathway cooperate to recruit the stem cell factor SOX2 in expanding and sustaining the accumulation of urothelial CSCs. Mechanistically, COX2/PGE2 signaling induced promoter methylation of let-7, resulting in its downregulation and subsequent SOX2 upregulation. YAP1 induced SOX2 expression more directly by binding its enhancer region. In UCB clinical specimens, positive correlations in the expression of SOX2, COX2, and YAP1 were observed, with coexpression of COX2 and YAP1 particularly commonly observed. Additional investigations suggested that activation of the COX2/PGE2 and YAP1 pathways also promoted acquired resistance to EGFR inhibitors in basal-type UCB. In a mouse xenograft model of UCB, dual inhibition of COX2 and YAP1 elicited a long-lasting therapeutic response by limiting CSC expansion after chemotherapy and EGFR inhibition. Our findings provide a preclinical rationale to target these pathways concurrently with systemic chemotherapy as a strategy to improve the clinical management of UCB.Significance: These findings offer a preclinical rationale to target the COX2 and YAP1 pathways concurrently with systemic chemotherapy to improve the clinical management of UCB, based on evidence that these two pathways expand cancer stem-like cell populations that mediate resistance to chemotherapy. Cancer Res; 78(1); 168-81. ©2017 AACR.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Ciclo-Oxigenase 2/metabolismo , Células-Tronco Neoplásicas/metabolismo , Fosfoproteínas/metabolismo , Neoplasias da Bexiga Urinária/tratamento farmacológico , Neoplasias da Bexiga Urinária/patologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Cisplatino/administração & dosagem , Ciclo-Oxigenase 2/genética , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos Nus , Células-Tronco Neoplásicas/patologia , Fosfoproteínas/genética , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Fatores de Transcrição , Neoplasias da Bexiga Urinária/metabolismo , Urotélio/patologia , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas de Sinalização YAP , Gencitabina
15.
PLoS One ; 12(7): e0180181, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28692661

RESUMO

Cancer stem cells (CSCs) play an important role in the clonogenic growth and metastasis of pancreatic ductal adenocarcinoma (PDAC). A hallmark of PDAC is the desmoplastic reaction, but the impact of the tumor microenvironment (TME) on CSCs is unknown. In order to better understand the mechanisms, we examined the impact of extracellular matrix (ECM) proteins on PDAC CSCs. We quantified the effect of ECM proteins, ß1-integrin, and focal adhesion kinase (FAK) on clonogenic PDAC growth and migration in vitro and tumor initiation, growth, and metastasis in vivo in nude mice using shRNA and overexpression constructs as well as small molecule FAK inhibitors. Type I collagen increased PDAC tumor initiating potential, self-renewal, and the frequency of CSCs through the activation of FAK. FAK overexpression increased tumor initiation, whereas a dominant negative FAK mutant or FAK kinase inhibitors reduced clonogenic PDAC growth in vitro and in vivo. Moreover, the FAK inhibitor VS-4718 extended the anti-tumor response to gemcitabine and nab-paclitaxel in patient-derived PDAC xenografts, and the loss of FAK expression limited metastatic dissemination of orthotopic xenografts. Type I collagen enhances PDAC CSCs, and both kinase-dependent and independent activities of FAK impact PDAC tumor initiation, self-renewal, and metastasis. The anti-tumor impact of FAK inhibitors in combination with standard chemotherapy support the clinical testing of this combination.


Assuntos
Carcinoma Ductal Pancreático/enzimologia , Carcinoma Ductal Pancreático/patologia , Matriz Extracelular/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Células-Tronco Neoplásicas/metabolismo , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/patologia , Transdução de Sinais , Aldeído Desidrogenase/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Autorrenovação Celular/efeitos dos fármacos , Células Clonais , Colágeno Tipo I/metabolismo , Matriz Extracelular/efeitos dos fármacos , Humanos , Integrina beta1/metabolismo , Camundongos Nus , Metástase Neoplásica , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Neoplasias Pancreáticas
16.
Mol Cancer Ther ; 15(11): 2733-2739, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27573425

RESUMO

Despite improved outcomes in newly diagnosed multiple myeloma, virtually all patients relapse and ultimately develop drug-resistant disease. Aberrant RAS/MAPK signaling is activated in the majority of relapsed/refractory multiple myeloma patients, but its biological consequences are not fully understood. Self-renewal, as defined by the long-term maintenance of clonogenic growth, is essential for disease relapse, and we examined the role of RAS/MAPK activation on multiple myeloma self-renewal by targeting IQ motif-containing GTPase-activating protein 1 (IQGAP1), an intracellular scaffold protein required for mutant RAS signaling. We found that loss of IQGAP1 expression decreased MAPK signaling, cell-cycle progression, and tumor colony formation. Similarly, a peptide mimicking the WW domain of IQGAP1 that interacts with ERK inhibited the clonogenic growth and self-renewal of multiple myeloma cell lines and primary clinical specimens in vitro as well as tumor-initiating cell frequency in immunodeficient mice. During multiple myeloma progression, self-renewal may be enhanced by aberrant RAS/MAPK signaling and inhibited by targeting IQGAP1. Mol Cancer Ther; 15(11); 2733-9. ©2016 AACR.


Assuntos
Autorrenovação Celular , Evolução Clonal , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Células-Tronco Neoplásicas/metabolismo , Proteínas Ativadoras de ras GTPase/metabolismo , Animais , Mimetismo Biológico , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Autorrenovação Celular/efeitos dos fármacos , Autorrenovação Celular/genética , Evolução Clonal/efeitos dos fármacos , Evolução Clonal/genética , Modelos Animais de Doenças , Feminino , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/mortalidade , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Peptídeos/química , Peptídeos/farmacologia , Domínios e Motivos de Interação entre Proteínas , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas Ativadoras de ras GTPase/antagonistas & inibidores , Proteínas Ativadoras de ras GTPase/química
17.
Mol Cancer Res ; 12(1): 155-64, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24249679

RESUMO

UNLABELLED: Cancer stem cell characteristics, especially their self-renewal and clonogenic potentials, play an essential role in malignant progression and response to anticancer therapies. Currently, it remains largely unknown what pathways are involved in the regulation of cancer cell stemness and differentiation. Previously, we found that delta-like 1 homolog (Drosophila) or DLK1, a developmentally regulated gene, plays a critical role in the regulation of differentiation, self-renewal, and tumorigenic growth of neuroblastoma cells. Here, we show that DLK1 specifically interacts with the prohibitin 1 (PHB1) and PHB2, two closely related genes with pleiotropic functions, including regulation of mitochondrial function and gene transcription. DLK1 interacts with the PHB1-PHB2 complex via its cytoplasmic domain and regulates mitochondrial functions, including mitochondrial membrane potential and production of reactive oxygen species. We have further found that PHB1 and especially PHB2 regulate cancer cell self-renewal as well as their clonogenic potential. Hence, the DLK1-PHB interaction constitutes a new signaling pathway that maintains clonogenicity and self-renewal potential of cancer cells. IMPLICATIONS: This study provides a new mechanistic insight into the regulation of the stem cell characteristics of cancer cells.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , Células-Tronco Neoplásicas/patologia , Neuroblastoma/patologia , Proteínas Repressoras/metabolismo , Proteínas de Ligação ao Cálcio , Diferenciação Celular , Linhagem Celular Tumoral , Células HEK293 , Células Hep G2 , Humanos , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Proibitinas , Interferência de RNA , RNA Interferente Pequeno , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Transcrição Gênica
18.
Cancer Lett ; 318(1): 26-33, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22142700

RESUMO

The stem cell-like characteristics of tumor cells are not only essential for tumor development and malignant progression, but also significantly contribute to therapy resistance. However, it remains poorly understood how cancer cell differentiation or stemness is regulated in vivo. We investigated the role of the stem cell gene DLK1, or delta-like 1 homolog (Drosophila), in the regulation of cancer cell differentiation in vivo using neuroblastoma (NB) xenografts as a model. We found that loss-of-function mutants of DLK1 significantly enhanced NB cell differentiation in vivo likely by increasing the basal phosphorylation of MEK and ERK kinases, a mechanism that has been shown to facilitate neuronal differentiation. We also found that DLK1(+) cells are preferentially located in hypoxic regions. These results clearly demonstrate that DLK1 plays an important role in the maintenance of undifferentiated, stem cell-like phenotypes of NB cells in vivo.


Assuntos
Diferenciação Celular , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Neovascularização Patológica , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Animais , Western Blotting , Proteínas de Ligação ao Cálcio , Proliferação de Células , Imunofluorescência , Humanos , Técnicas Imunoenzimáticas , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Nus , Neuroblastoma/irrigação sanguínea
19.
Artigo em Inglês | IMSEAR | ID: sea-172577

RESUMO

Stabbing is the most common method of homicide in developing countries like Bangladesh, due to poverty, over population, joblessness, political unrest, etc. The reported case is of a 27 years old man stabbed on the front of the left thigh, a relatively unusual site by a sharp pointed knife by some snatchers while sitting on a rickshaw. On medicolegal point of view the injury was homicidal in nature to run away without having a motive to kill the person. The site was easily approachable for the snatchers. We need to create awareness among general population about the circumstances and probable mishaps that can happen unexpectedly.

20.
Artigo em Inglês | IMSEAR | ID: sea-172547

RESUMO

Background: Every year, world wide, 200 million women become pregnant. The development of urban areas allowed women to receive more care and treatment. However, in rural areas such measures are not available to every woman. Data on delivery practice of rural woman may help the social and public health planners and decision makers to minimize and prevent maternal mortality and morbidity ensuring safe motherhood. Objective: The aim of the study was to observe the delivery practice of rural women of Bangladesh. Materials and method: A cross-sectional study was conducted and data were collected from Dhamrai upazila, Dhaka, Bangladesh in April 2008. Total 159 women of reproductive age group at least having one child were selected purposively to elicit information on various demographic, socioeconomic, cultural and selected programmatic variables including maternal health care and delivery practices. Results: Among the respondents about 55% were literate. Majority (80%) of the respondents delivered at home and most of the them (71%) felt that home delivery was comfortable where as about 29% of the respondents were compelled to deliver at home due to family decision and financial constraint. Among the deliveries about 82% occurred normally and 18.2% were by cesarean section. A considerable percentage of deliveries (49%) were attended by traditional birth attendants. Blade was used for cutting umbilical cord in majority of the cases (74%) who delivered at home. Most of the respondents (90%) took ante natal check up and about 74% were vaccinated by tetanus toxoid. Conclusion: The results of the study suggest that a lot of work is still to do for the policy makers and health planners to target, plan, develop and deliver maternal health services to the rural women of Bangladesh.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA