RESUMO
Acute myeloid leukaemia (AML) is a heterogeneous clonal malignancy of hematopoietic progenitor cells. The Wnt pathway and its downstream targets are tightly regulated by ß-catenin. We recently discovered a new protein, FLYWCH1, which can directly bind nuclear ß-catenin. Herein, we studied the FLYWCH1/ß-catenin pathway in AML cells using qRT-PCR, Western blot, and immunofluorescence assays. In addition, the stemness activity and cell cycle were analysed by the colony-forming unit (CFU) using methylcellulose-based and Propidium iodide/flow cytometry assays. We found that FLYWCH1 mRNA and protein were differentially expressed in the AML cell lines. C-Myc, cyclin D1, and c-Jun expression decreased in the presence of higher FLYWCH1 expression, and vice versa. There appeared to be the loss of FLYWCH1 expression in dividing cells. The sub-G0 phase was prolonged and shortened in the low and high FLYWCH1 expression cell lines, respectively. The G0/G1 arrest correlated with FLYWCH1-expression, and these cell lines also formed colonies, whereas the low FLYWCH1 expression cell lines could not. Thus, FLYWCH1 functions as a negative regulator of the Wnt/ß-catenin pathway in AML.
Assuntos
Proteínas de Ligação a DNA/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Ciclo Celular/genética , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Imunofluorescência , Humanos , Células-Tronco Neoplásicas/metabolismo , RNA Mensageiro/genética , Via de Sinalização WntRESUMO
PURPOSE: Expression of members of the calpain system are associated with clinical outcome of patients with, amongst others, breast and ovarian cancers, with calpain-2 expression in ovarian cancer being implicated in chemo-resistance and survival. This study aimed, using a large patient cohort and in vitro models, to verify its importance and further investigate the role in ovarian cancer chemoresponse. METHODS: Calpain-1, calpain-2, calpain-4 and calpastatin expression were evaluated in primary ovarian carcinomas (n = 575) by immunohistochemistry. Protein expression was assessed, via western blotting, in five ovarian cancer cell lines with various sensitivities towards cisplatin/carboplatin. In vitro calpain activity was inhibited by calpeptin treatment to assess changes in platinum sensitivity by proliferation assay, with expression of genes associated with epithelial-mesenchymal transition being examined by RT2 Profiler™ PCR Array. RESULTS: The current study confirmed previous data that high calpain-2 expression is associated with poor overall survival (P = 0.026) and that calpain-1 was not associated with overall survival or progression-free survival. Low expression of calpastatin (P = 0.010) and calpain-4 (P = 0.003) were also associated with adverse survival. Such prognostic associations do not seem to be linked with altered tumour sensitivity towards platinum-based chemotherapy. Interestingly, low calpain-1 expression was more frequent in patients with confined tumours (stage 1) (χ2 = 11.310, df = 1, P = 0.001). Calpain and calpastatin expression varied among ovarian cancer cell lines yet their expression levels were similar between chemo-sensitive cells and resistant counterparts. Moreover, calpeptin treatment did not alter cellular response to platinum-based chemotherapy or epithelial-mesenchymal transition-related gene expression. CONCLUSIONS: The conventional calpains and calpastatin have been confirmed to play an important role in ovarian cancer; however, the precise mechanisms whereby they exert effects remain to be elucidated.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Calpaína/metabolismo , Neoplasias Ovarianas/patologia , Adenocarcinoma de Células Claras/tratamento farmacológico , Adenocarcinoma de Células Claras/metabolismo , Adenocarcinoma de Células Claras/patologia , Adenocarcinoma Mucinoso/tratamento farmacológico , Adenocarcinoma Mucinoso/metabolismo , Adenocarcinoma Mucinoso/patologia , Proliferação de Células , Estudos de Coortes , Cistadenocarcinoma Seroso/tratamento farmacológico , Cistadenocarcinoma Seroso/metabolismo , Cistadenocarcinoma Seroso/patologia , Neoplasias do Endométrio/tratamento farmacológico , Neoplasias do Endométrio/metabolismo , Neoplasias do Endométrio/patologia , Transição Epitelial-Mesenquimal , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Prognóstico , Taxa de Sobrevida , Células Tumorais CultivadasRESUMO
The AlamarBlue assay is based on fluorometric detection of metabolic mitochondrial activity of cells. In this study, we determined the methodology for application of the assay to radiation response experiments in 96-well plates. AlamarBlue was added and its reduction measured 7 hours later. Selection of the initial number of plated cells was important so that the number of proliferating cells remains lower than the critical number that produced full AlamarBlue reduction (plateau phase) at the time points of measurements. Culture medium was replaced twice a week to avoid suppression of viability due to nutrient competition and metabolic waste accumulation. There was no need to replace culture medium before adding AlamarBlue. Cell proliferation continued after irradiation and the suppression effect on cell viability was most evident on day 8. At this time point, by comparing measurements from irradiated vs. non-irradiated cells, for various dose levels, a viability dose response curve was plotted. Immediately after the 8(th) day (nadir), cells started to re-grow at a rate inversely related to the radiation dose. By comparing measurements at the time point of nadir vs. a convenient subsequent time point, re-growth dose response abilities were plotted, simulating clonogenic assays.
