RESUMO
OBJECTIVE: The aim of this study was to compare response rates and survival in women with "platinum resistant" epithelial ovarian cancer (EOC) who received further platinum-based or nonplatinum chemotherapy for treatment at first relapse. METHODS: Patients with high-grade EOC (including fallopian tube and peritoneal cancer) of all histologies recruited to the Australian Ovarian Cancer Study (AOCS) and treated with platinum-based primary chemotherapy were included. Response to second-line chemotherapy, overall survival (OS) and survival after treatment for first progression (OS2) were determined in all histologies and separately in women with high-grade serous tumors. RESULTS: Of the 341 patients classified as platinum-resistant by the 6-month threshold, 243 (71%) were treated with chemotherapy at relapse. CA-125 response rates to platinum-based chemotherapy were significantly higher compared to nonplatinum chemotherapy (51% vs 21%, Pâ¯<â¯0.001). Among patients with a platinum-free interval (PFI) of 3-6â¯months, OS2 in patients treated with platinum was significantly longer compared to individuals receiving nonplatinum-based treatment (median 17.67â¯months, 95% CI: 14.79-20.75 vs. 10.62â¯months, 95% CI: 8.02-12.72, Pâ¯=â¯0.022). The patterns were similar when restricted to patients with high-grade serous histology. In patients with PFI <3â¯months, there was no significant difference in response or survival according to type of second-line treatment. CONCLUSIONS: Our findings further question the use of a 6-month PFI as an arbitrary threshold for subsequent treatment decision-making. Some patients considered "platinum resistant" still derive clinical benefit from platinum-based chemotherapy. Biomarkers of platinum sensitivity are needed in clinical practice to identify potential responders who should be offered re-treatment with platinum.
Assuntos
Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Epiteliais e Glandulares/tratamento farmacológico , Compostos Organoplatínicos/uso terapêutico , Neoplasias Ovarianas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Epitelial do Ovário , Estudos de Coortes , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Epiteliais e Glandulares/patologia , Compostos Organoplatínicos/administração & dosagem , Neoplasias Ovarianas/patologia , Resultado do TratamentoRESUMO
We earlier reported synergy between tumor necrosis factor-α (TNF-α) and transforming growth factor-ß1 (TGF-ß1) for apoptosis in human umbilical vein endothelium (HUVEC). Here, we study morphological change by circularity measurement of HUVEC surviving this cytokine induced synergistic apoptosis. Contrasting with reports by others studying bovine endothelium, HUVEC did not change morphology in response to TGF-ß1. TNF-α markedly elongated cells (p<0.001) and this further increased with combination of the two cytokines (p<0.001), while elongation was accompanied by increased actin stress fibres. Transdifferentiation of HUVEC to a smooth muscle cell phenotype as reported elsewhere was excluded in the current study.
Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Fator de Crescimento Transformador beta/farmacologia , Fator de Necrose Tumoral alfa/farmacologia , Apoptose , Diferenciação Celular , Transdiferenciação Celular , Células Cultivadas , Humanos , Miócitos de Músculo Liso/metabolismo , Fibras de Estresse/metabolismoRESUMO
OBJECTIVE: ABCB1 encodes the multi-drug efflux pump P-glycoprotein (P-gp) and has been implicated in multi-drug resistance. We comprehensively evaluated this gene and flanking regions for an association with clinical outcome in epithelial ovarian cancer (EOC). METHODS: The best candidates from fine-mapping analysis of 21 ABCB1 SNPs tagging C1236T (rs1128503), G2677T/A (rs2032582), and C3435T (rs1045642) were analysed in 4616 European invasive EOC patients from thirteen Ovarian Cancer Association Consortium (OCAC) studies and The Cancer Genome Atlas (TCGA). Additionally we analysed 1,562 imputed SNPs around ABCB1 in patients receiving cytoreductive surgery and either 'standard' first-line paclitaxel-carboplatin chemotherapy (n=1158) or any first-line chemotherapy regimen (n=2867). We also evaluated ABCB1 expression in primary tumours from 143 EOC patients. RESULT: Fine-mapping revealed that rs1128503, rs2032582, and rs1045642 were the best candidates in optimally debulked patients. However, we observed no significant association between any SNP and either progression-free survival or overall survival in analysis of data from 14 studies. There was a marginal association between rs1128503 and overall survival in patients with nil residual disease (HR 0.88, 95% CI 0.77-1.01; p=0.07). In contrast, ABCB1 expression in the primary tumour may confer worse prognosis in patients with sub-optimally debulked tumours. CONCLUSION: Our study represents the largest analysis of ABCB1 SNPs and EOC progression and survival to date, but has not identified additional signals, or validated reported associations with progression-free survival for rs1128503, rs2032582, and rs1045642. However, we cannot rule out the possibility of a subtle effect of rs1128503, or other SNPs linked to it, on overall survival.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resistência a Múltiplos Medicamentos/genética , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Epiteliais e Glandulares/tratamento farmacológico , Neoplasias Epiteliais e Glandulares/genética , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP , Carboplatina/administração & dosagem , Carcinoma Epitelial do Ovário , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Epiteliais e Glandulares/cirurgia , Neoplasias Ovarianas/cirurgia , Paclitaxel/administração & dosagem , Farmacogenética , Polimorfismo de Nucleotídeo Único , Modelos de Riscos ProporcionaisRESUMO
BACKGROUND: The four-transmembrane MAL2 protein is frequently overexpressed in breast carcinoma, and MAL2 overexpression is associated with gain of the corresponding locus at chromosome 8q24.12. Independent expression microarray studies predict MAL2 overexpression in ovarian carcinoma, but these had remained unconfirmed. MAL2 binds tumor protein D52 (TPD52), which is frequently overexpressed in ovarian carcinoma, but the clinical significance of MAL2 and TPD52 overexpression was unknown. METHODS: Immunohistochemical analyses of MAL2 and TPD52 expression were performed using tissue microarray sections including benign, borderline and malignant epithelial ovarian tumours. Inmmunohistochemical staining intensity and distribution was assessed both visually and digitally. RESULTS: MAL2 and TPD52 were significantly overexpressed in high-grade serous carcinomas compared with serous borderline tumours. MAL2 expression was highest in serous carcinomas relative to other histological subtypes, whereas TPD52 expression was highest in clear cell carcinomas. MAL2 expression was not related to patient survival, however high-level TPD52 staining was significantly associated with improved overall survival in patients with stage III serous ovarian carcinoma (log-rank test, p < 0.001; n = 124) and was an independent predictor of survival in the overall carcinoma cohort (hazard ratio (HR), 0.498; 95% confidence interval (CI), 0.34-0.728; p < 0.001; n = 221), and in serous carcinomas (HR, 0.440; 95% CI, 0.294-0.658; p < 0.001; n = 182). CONCLUSIONS: MAL2 is frequently overexpressed in ovarian carcinoma, and TPD52 overexpression is a favourable independent prognostic marker of potential value in the management of ovarian carcinoma patients.
Assuntos
Adenocarcinoma de Células Claras/metabolismo , Adenocarcinoma Mucinoso/metabolismo , Cistadenocarcinoma Seroso/metabolismo , Neoplasias do Endométrio/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias Ovarianas/metabolismo , Proteolipídeos/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Adenocarcinoma de Células Claras/patologia , Adenocarcinoma Mucinoso/patologia , Biomarcadores Tumorais/metabolismo , Estudos de Coortes , Cistadenocarcinoma Seroso/patologia , Neoplasias do Endométrio/patologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Pessoa de Meia-Idade , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina , Estadiamento de Neoplasias , Neoplasia Residual/metabolismo , Neoplasia Residual/patologia , Neoplasias Ovarianas/patologia , Prognóstico , Taxa de Sobrevida , Análise Serial de TecidosRESUMO
Purpose: Women with epithelial ovarian cancer generally have a poor prognosis; however, a subset of patients has an unexpected dramatic and durable response to treatment. We sought to identify clinical, pathological, and molecular determinants of exceptional survival in women with high-grade serous cancer (HGSC), a disease associated with the majority of ovarian cancer deaths.Experimental Design: We evaluated the histories of 2,283 ovarian cancer patients and, after applying stringent clinical and pathological selection criteria, identified 96 with HGSC that represented significant outliers in terms of treatment response and overall survival. Patient samples were characterized immunohistochemically and by genome sequencing.Results: Different patterns of clinical response were seen: long progression-free survival (Long-PFS), multiple objective responses to chemotherapy (Multiple Responder), and/or greater than 10-year overall survival (Long-Term Survivors). Pathogenic germline and somatic mutations in genes involved in homologous recombination (HR) repair were enriched in all three groups relative to a population-based series. However, 29% of 10-year survivors lacked an identifiable HR pathway alteration, and tumors from these patients had increased Ki-67 staining. CD8+ tumor-infiltrating lymphocytes were more commonly present in Long-Term Survivors. RB1 loss was associated with long progression-free and overall survival. HR deficiency and RB1 loss were correlated, and co-occurrence was significantly associated with prolonged survival.Conclusions: There was diversity in the clinical trajectory of exceptional survivors associated with multiple molecular determinants of exceptional outcome in HGSC patients. Concurrent HR deficiency and RB1 loss were associated with favorable outcomes, suggesting that co-occurrence of specific mutations might mediate durable responses in such patients. Clin Cancer Res; 24(3); 569-80. ©2017 AACRSee related commentary by Peng and Mills, p. 508.
Assuntos
Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/mortalidade , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/mortalidade , Reparo de DNA por Recombinação , Proteína do Retinoblastoma/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais , Cistadenocarcinoma Seroso/diagnóstico , Feminino , Recombinação Homóloga , Humanos , Pessoa de Meia-Idade , Mutação , Gradação de Tumores , Estadiamento de Neoplasias , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/metabolismo , Prognóstico , Proteína do Retinoblastoma/metabolismo , Transdução de Sinais , Análise de Sobrevida , Avaliação de SintomasRESUMO
ABCB1 (adenosine triphosphate-binding cassette transporter B1) mediates cellular elimination of many chemotherapeutic agents including paclitaxel, which is commonly used to treat ovarian cancer. A significant association between common single nucleotide polymorphisms (SNPs) in ABCB1 and progression-free survival has been reported in patients with ovarian cancer. Variable paclitaxel clearance due to genotype specific differences in ABCB1 activity in cancer cells and/or normal tissues may underlie the association. Using cell-based models, we evaluated the correlations between ABCB1 expression, polymorphisms, transporter activity and paclitaxel sensitivity in ovarian cancer (n = 10) and lymphoblastoid (n = 19) cell lines. Close associations between ABCB1 expression, transporter function and paclitaxel sensitivity were found in lymphoblastoid cell lines, although we could not demonstrate an association with common SNPs. In ovarian cancer cell lines, ABCB1 expression was low and the association between expression and function was lost. These results suggest that ABCB1 related survival difference in ovarian cancer patients is more likely to be due to differential whole body paclitaxel clearance mediated by normal cells rather than a direct effect on cancer cells.
Assuntos
Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Paclitaxel/farmacologia , Polimorfismo de Nucleotídeo Único/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Feminino , Genótipo , HumanosRESUMO
PURPOSE: Low-grade serous ovarian carcinomas (LGSC) are Ras pathway-mutated, TP53 wild-type, and frequently associated with borderline tumors. Patients with LGSCs respond poorly to platinum-based chemotherapy and may benefit from pathway-targeted agents. High-grade serous carcinomas (HGSC) are TP53-mutated and are thought to be rarely associated with borderline tumors. We sought to determine whether borderline histology associated with grade 2 or 3 carcinoma was an indicator of Ras mutation, and we explored the molecular relationship between coexisting invasive and borderline histologies. EXPERIMENTAL DESIGN: We reviewed >1,200 patients and identified 102 serous carcinomas with adjacent borderline regions for analyses, including candidate mutation screening, copy number, and gene expression profiling. RESULTS: We found a similar frequency of low, moderate, and high-grade carcinomas with coexisting borderline histology. BRAF/KRAS alterations were common in LGSC; however, we also found recurrent NRAS mutations. Whereas borderline tumors harbored BRAF/KRAS mutations, NRAS mutations were restricted to carcinomas, representing the first example of a Ras oncogene with an obligatory association with invasive serous cancer. Coexisting borderline and invasive components showed nearly identical genomic profiles. Grade 2 cases with coexisting borderline included tumors with molecular features of LGSC, whereas others were typical of HGSC. However, all grade 3 carcinomas with coexisting borderline histology were molecularly indistinguishable from typical HGSC. CONCLUSION: Our findings suggest that NRAS is an oncogenic driver in serous ovarian tumors. We demonstrate that borderline histology is an unreliable predictor of Ras pathway aberration and underscore an important role for molecular classification in identifying patients that may benefit from targeted agents.
Assuntos
Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/metabolismo , Mutação , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Proteína Supressora de Tumor p53/genética , Proteínas ras/genética , Proteínas ras/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Análise por Conglomerados , Estudos de Coortes , Cistadenocarcinoma Seroso/mortalidade , Cistadenocarcinoma Seroso/patologia , Variações do Número de Cópias de DNA , Feminino , Humanos , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Estadiamento de Neoplasias , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Polimorfismo de Nucleotídeo Único , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo , Transdução de Sinais , Adulto JovemRESUMO
BACKGROUND: ATP-binding cassette (ABC) transporters play various roles in cancer biology and drug resistance, but their association with outcomes in serous epithelial ovarian cancer (EOC) is unknown. METHODS: The relationship between clinical outcomes and ABC transporter gene expression in two independent cohorts of high-grade serous EOC tumors was assessed with real-time quantitative polymerase chain reaction, analysis of expression microarray data, and immunohistochemistry. Associations between clinical outcomes and ABCA transporter gene single nucleotide polymorphisms were tested in a genome-wide association study. Impact of short interfering RNA-mediated gene suppression was determined by colony forming and migration assays. Association with survival was assessed with Kaplan-Meier analysis and log-rank tests. All statistical tests were two-sided. RESULTS: Associations with outcome were observed with ABC transporters of the "A" subfamily, but not with multidrug transporters. High-level expression of ABCA1, ABCA6, ABCA8, and ABCA9 in primary tumors was statistically significantly associated with reduced survival in serous ovarian cancer patients. Low levels of ABCA5 and the C-allele of rs536009 were associated with shorter overall survival (hazard ratio for death = 1.50; 95% confidence interval [CI] =1.26 to 1.79; P = 6.5e-6). The combined expression pattern of ABCA1, ABCA5, and either ABCA8 or ABCA9 was associated with particularly poor outcome (mean overall survival in group with adverse ABCA1, ABCA5 and ABCA9 gene expression = 33.2 months, 95% CI = 26.4 to 40.1; vs 55.3 months in the group with favorable ABCA gene expression, 95% CI = 49.8 to 60.8; P = .001), independently of tumor stage or surgical debulking status. Suppression of cholesterol transporter ABCA1 inhibited ovarian cancer cell growth and migration in vitro, and statin treatment reduced ovarian cancer cell migration. CONCLUSIONS: Expression of ABCA transporters was associated with poor outcome in serous ovarian cancer, implicating lipid trafficking as a potentially important process in EOC.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/metabolismo , Neoplasias Epiteliais e Glandulares/genética , Neoplasias Epiteliais e Glandulares/metabolismo , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Polimorfismo de Nucleotídeo Único , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Carcinoma Epitelial do Ovário , Movimento Celular , Cistadenocarcinoma Seroso/mortalidade , Cistadenocarcinoma Seroso/patologia , Feminino , Regulação Neoplásica da Expressão Gênica , Estudo de Associação Genômica Ampla , Humanos , Estimativa de Kaplan-Meier , Gradação de Tumores , Neoplasias Epiteliais e Glandulares/mortalidade , Neoplasias Epiteliais e Glandulares/patologia , Células-Tronco Neoplásicas , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo RealRESUMO
PURPOSE: The frequency of BRCA1 and BRCA2 germ-line mutations in women with ovarian cancer is unclear; reports vary from 3% to 27%. The impact of germ-line mutation on response requires further investigation to understand its impact on treatment planning and clinical trial design. PATIENTS AND METHODS: Women with nonmucinous ovarian carcinoma (n = 1,001) enrolled onto a population-based, case-control study were screened for point mutations and large deletions in both genes. Survival outcomes and responses to multiple lines of chemotherapy were assessed. RESULTS: Germ-line mutations were found in 14.1% of patients overall, including 16.6% of serous cancer patients (high-gradeserous, 17.1%); [corrected] 44% had no reported family history of breast orovarian cancer.Patients carrying germ-line mutations had improved rates of progression-free and overall survival. In the relapse setting, patients carrying mutations more frequently responded to both platin- and nonplatin-based regimens than mutation-negative patients, even in patients with early relapse after primary treatment. Mutation-negative patients who responded to multiple cycles of platin-based treatment were more likely to carry somatic BRCA1/2 mutations. CONCLUSION: BRCA mutation status has a major influence on survival in ovarian cancer patients and should be an additional stratification factor in clinical trials. Treatment outcomes in BRCA1/2 carriers challenge conventional definitions of platin resistance, and mutation status may be able to contribute to decision making and systemic therapy selection in the relapse setting. Our data, together with the advent of poly(ADP-ribose) polymerase inhibitor trials, supports the recommendation that germ-line BRCA1/2 testing should be offered to all women diagnosed with nonmucinous, ovarian carcinoma, regardless of family history.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma/tratamento farmacológico , Carcinoma/genética , Genes BRCA1 , Genes BRCA2 , Mutação em Linhagem Germinativa , Taxa de Mutação , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Adenocarcinoma de Células Claras/tratamento farmacológico , Adenocarcinoma de Células Claras/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Austrália/epidemiologia , Neoplasias da Mama/genética , Carcinoma Endometrioide/tratamento farmacológico , Carcinoma Endometrioide/genética , Estudos de Casos e Controles , Estudos de Coortes , Cistadenocarcinoma Seroso/tratamento farmacológico , Cistadenocarcinoma Seroso/genética , Intervalo Livre de Doença , Resistencia a Medicamentos Antineoplásicos , Neoplasias das Tubas Uterinas/tratamento farmacológico , Neoplasias das Tubas Uterinas/genética , Feminino , Humanos , Estimativa de Kaplan-Meier , Anamnese , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Neoplasias Ovarianas/epidemiologia , Neoplasias Ovarianas/patologia , Neoplasias Peritoneais/tratamento farmacológico , Neoplasias Peritoneais/genética , Compostos de Platina/administração & dosagem , Mutação Puntual , Estudos Prospectivos , Recidiva , Resultado do TratamentoRESUMO
Molecular events leading to epithelial ovarian cancer are poorly understood but ovulatory hormones and a high number of life-time ovulations with concomitant proliferation, apoptosis, and inflammation, increases risk. We identified genes that are regulated during the estrous cycle in murine ovarian surface epithelium and analysed these profiles to identify genes dysregulated in human ovarian cancer, using publically available datasets. We identified 338 genes that are regulated in murine ovarian surface epithelium during the estrous cycle and dysregulated in ovarian cancer. Six of seven candidates selected for immunohistochemical validation were expressed in serous ovarian cancer, inclusion cysts, ovarian surface epithelium and in fallopian tube epithelium. Most were overexpressed in ovarian cancer compared with ovarian surface epithelium and/or inclusion cysts (EpCAM, EZH2, BIRC5) although BIRC5 and EZH2 were expressed as highly in fallopian tube epithelium as in ovarian cancer. We prioritised the 338 genes for those likely to be important for ovarian cancer development by in silico analyses of copy number aberration and mutation using publically available datasets and identified genes with established roles in ovarian cancer as well as novel genes for which we have evidence for involvement in ovarian cancer. Chromosome segregation emerged as an important process in which genes from our list of 338 were over-represented including two (BUB1, NCAPD2) for which there is evidence of amplification and mutation. NUAK2, upregulated in ovarian surface epithelium in proestrus and predicted to have a driver mutation in ovarian cancer, was examined in a larger cohort of serous ovarian cancer where patients with lower NUAK2 expression had shorter overall survival. In conclusion, defining genes that are activated in normal epithelium in the course of ovulation that are also dysregulated in cancer has identified a number of pathways and novel candidate genes that may contribute to the development of ovarian cancer.
Assuntos
Epitélio/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Genes Neoplásicos/genética , Estudos de Associação Genética , Neoplasias Ovarianas/etiologia , Neoplasias Ovarianas/genética , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adulto , Idoso , Animais , Estudos de Coortes , Epitélio/patologia , Ciclo Estral/genética , Feminino , Dosagem de Genes/genética , Humanos , Imuno-Histoquímica , Camundongos , Pessoa de Meia-Idade , Mutação/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias Ovarianas/patologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Apoptotic endothelium has been suggested to have microthrombotic and microembolic potential. While some describe pro-coagulant activities and platelet binding, others demonstrate maintained fibrinolytic protein and anti-platelet aggregatory activity. Canalicular fragmentation is unique to apoptotic endothelium and is suggested to facilitate size reduction of apoptotic cells to reduce microembolic potential. Despite the potential importance of apoptotic microemboli, there are no reports characterizing changes in cell size and shape during endothelial apoptosis. METHODS: Here, we describe transmission and scanning electron microscopic studies of apoptotic endothelium and compare changes seen with apoptotic HL-60 cells incapable of canalicular fragmentation. RESULTS: We demonstrate reduced endothelial size (p<0.05) with progressive apoptosis relative to apoptotic HL-60 cells. Mechanical stress accelerated size reduction of apoptotic endothelium(P< 0.01) but did not affect the size of apoptotic HL-60 cells. Mechanical stress also increased circularity in apoptotic endothelium (p<0.01), suggested to facilitate passage through small vessels. Earlier work indicated that canaliculi form through plasma membrane invagination, but we report fusion of small vesicles contributing to canalicular growth, while canaliculi fuse to form large vacuoles and also dilate at late stages of apoptosis. CONCLUSIONS: These observations are consistent with the suggestion that endothelium is adapted to minimize microembolic potential and that canalicular fragmentation contributes to this.
Assuntos
Apoptose , Embolia/patologia , Endotélio Vascular/ultraestrutura , Membrana Celular/ultraestrutura , Tamanho Celular , Vesículas Citoplasmáticas/ultraestrutura , Células HL-60 , Humanos , Microcirculação , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Estresse Mecânico , Veias Umbilicais/citologia , Vacúolos/ultraestruturaRESUMO
Serum deprivation stimulates endothelial apoptosis while albumin inhibits this and has been proposed as important in confining apoptotic remodelling to poorly perfused vessels. Tumour necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta are also reported to induce endothelial apoptosis. To investigate the comparative roles of these stimuli, the effect of TNF-alpha and TGF-beta, alone or in combination, in the presence or absence of serum or albumin was studied. There was strong synergy between the cytokines in inducing human umbilical vein endothelial cell apoptosis, but only in the absence of serum. Synergy was destroyed by boiling cytokines and was not affected by polymyxin B. Dose response experiments revealed greater activity of TGF-beta(1) than TGF-beta(2). The synergy was protein synthesis dependent and apoptosis was confirmed by DNA gel electrophoresis, transmission electron microscopy and FACS analysis. Data suggests a role for synergistic activation of endothelial cell apoptosis by TNF-alpha and TGF-beta(1) but perhaps only in poorly perfused vessels deprived of serum factors.