AMANDA IKEGAMI
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Dissertação IPEN-doc 25674 Avaliação in vitro e in vivo do impacto do silenciamento do gene NF-kB1 no ciclo celular, capacidade proliferativa e na radiossensibilidade do adenocarcinoma renal2019 - IKEGAMI, AMANDAO carcinoma de células renais (CCR) é responsável por, aproximadamente, 1 a 3% das neoplasias malignas humanas e, dentre os tumores urológicos, é o mais agressivo. A heterogeneidade biológica, a resistência aos fármacos e os efeitos colaterais à quimioterapia são os maiores obstáculos ao tratamento eficaz do CCR. Várias moléculas vêm sendo correlacionadas com o fenótipo agressivo deste tumor, sendo uma delas o fator de transcrição NF-kB. Estudos demonstraram a ativação de NF-kB no CCR e muitos apontaram NF-kB1 (p50) como uma molécula importante na progressão tumoral e metástase. Neste trabalho, foi utilizada a técnica de silenciamento gênico de interferência por RNA - Short hairpin RNA (shRNA) - para diminuir a expressão de NF-kB1 em células murinas de carcinoma de células renais (Renca). Verificou-se que, in vitro, a diminuição da expressão do gene NF-kB1 reduz a capacidade proliferativa das células Renca e aumenta a taxa de apoptose tardia/necrose e a quantidade de células na fase G2/M do ciclo celular. Além disso, as análises de Western blot revelaram aumento significativo da expressão proteica de Ciclina B1 e Bax. A regulação negativa da p50 também alterou a capacidade clonogênica das células que, conjugada à irradiação ionizante, levou à diminuição significativa da fração de sobrevivência das células Renca e diminuiu a viabilidade celular verificada através do ensaio de MTS. Os ensaios in vivo mostraram que as células com baixa expressão de NF-kB1 (Renca-shRNA- NF-kB1) apresentam tumorigenicidade significativamente menor que as células controle e as análises de imunohistoquímica mostraram aumento significativo das áres necróticas dos tumores Renca-shRNA-NF-kB1, além da diminuição da marcação de Ki-67, um marcador de proliferação celular. Os resultados indicam que a diminuição da expressão de NF-kB1 pode suprimir a tumorigênese do CCR, induzindo apoptose tardia/necrose, podendo ser um potencial alvo terapêutico para este carcinoma.Resumo IPEN-doc 24634 Downregulation of NF-ΚB1 enhances the radiosensitivity of renal cell carcinoma2017 - IKEGAMI, AMANDA; SILVA, LUIZ F.T. da; BELLINI, MARIA H.Introduction: Clear cell renal cell carcinoma (ccRCC) accounts for ∼80% of all renal cell carcinomas (RCC) and has the Von Hippel–Lindau (VHL) tumor suppressor gene mutated. The lack of VHL protein leads to a constitutionally active Hypoxia Inducible Factor (HIF) pathway that confers both chemoresistance and radioresistance for renal tumor. HIF pathway is known to interact with the transcription factor nuclear factor kappa B (NF-kB). Increased NF-κB activity is associated with the development and progression of RCC (IKEGAMI A, TEIXEIRA LF. BRAGA MS et al. The American Society for Cell Biology 2016; 26: 3948-3955). Objective: Evaluate the synergistic effect of NF-kB1 knockdown and ionizing radiation in murine renal adenocarcinoma cell line. Methods: The murine renal adenocarcinoma cell line (Renca cells) (ATCC, USA) was cultured in RPMI 1640 supplemented with 10% FBS and penicillin/streptomycin. Lentiviral shRNA vector was used to knockdown of NF-KB1 gene in Renca cells, as described previously (1). In the clonogenic cell survival assay, the cells were irradiated by 60Co source in the range from 0 to 10 Gy, using the GammaCell 220 – Irradiation Unit of Canadian-Atomic Energy Commision Ltd. (CTR-IPEN). After 10-14 days of culture, cell colonies were fixed and stained with formaldehyde 4% and rhodamine B 2% and counted. To assess cell viability, tetrazolium [3-(4,5-dimethylthiazol-2-yl)-5- (3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-MTS] was performed within 24 hours after irradiation at a dose of 10Gy. The survival variables α e β were fitted according to the linear quadratic equation (SF=exp[-αD-βD2]); SF=survival fraction, D=dose of irradiation and P value was determined by F test. Multiple comparisons were assessed by One-way ANOVA followed by Bonferroni´s tests with GraphPad Prism version 6.0 software. P< 0.05 was considered statistically significant. Data are shown as the mean ± SD. Results: The Renca-shRNA-NF-kB1 cells were found to be significantly more radiosensitive than controls - Renca-WT and Renca-Mock, (P<0.001 vs Renca-Mock). The ratio α/β was increased in Renca-shRNA-NF-kB1: -0.177±0.677 compared with 7.368±1.833 and 11.960±5.240 of the Renca- WT and Renca-Mock, respectively. There was no significant difference in the survival fraction between Renca-WT and Renca-Mock groups. The lethal dose 50% (LD50) of Renca-WT was 3.33 Gy and Renca-Mock was 3.288 Gy whereas for the Renca-shRNA-NF-kB1 group it was 2.08 Gy. Corroborating these data, the Renca-shRNA-NF-kB1 showed reduction of 16.75±0.06% in the viability when compared to the Renca-Mock (P<0.001). Conclusion: The knockdown of NF-kB1 gene mediated by shRNA on Renca cells led to a decrease in the radioresistance. Therefore, this gene can be a therapeutic target for CCR treatment.Artigo IPEN-doc 24344 Knockdown of NF-κB1 by shRNA inhibits the growth of renal cell carcinoma in vitro and in vivo2018 - IKEGAMI, AMANDA; TEIXEIRA, LUIZ F.S.; BRAGA, MARINA S.; DIAS, MATHEUS H. dos S.; LOPES, EDUARDO C.; BELLINI, MARIA H.Renal cell carcinoma (RCC) accounts for approximately 2-3% of human malignancies and is the most aggressive among urologic tumors. Biological heterogeneity, drug resistance and chemotherapy side effects are the biggest obstacles to the effective treatment of RCC. The NF-кB transcription factor is one of several molecules identified to be responsible for the aggressive phenotype of this tumor. In the past decade, several studies have demonstrated the activation of NF-kB in RCC, and many implicated NF- κB1 (p50) as an important molecule in tumor progression and metastasis. In the present study, a lentivirus was used to deliver shRNA targeting NF-κB1 into mouse renal cell carcinoma (Renca) cells. It was determined that the knockdown of the NF-κB1 gene led to a reduction in cell proliferation and late apoptosis/necrosis in vitro. Flow cytometry analysis demonstrated G2/M arrest in the cells. In addition, immunoblotting analysis revealed a significant increase in cyclin B1 and Bax. In vivo experiments showed that Renca-shRNA-NF-кB1 cells have significantly diminished tumorigenicity. Moreover, immunohistochemical analysis revealed an increase in necrotic areas of Renca-shRNANF- кB1 tumors. Thus, this study indicates that downregulation of NF-кB1 can suppress RCC tumorigenesis by inducing late apoptosis/necrosis. Therefore, NF-кB1 may be a potential therapeutic target for RCC.Artigo IPEN-doc 23209 Essential elements as biomarkers of acute kidney injury and spontaneous reversion2018 - SILVA, REGIANE M. da; KO, GUI MI; SILVA, RINALDO F.; VIEIRA, LUDMILA C.; PAULA, RAFAEL V. de; MARUMO, JULIO T.; IKEGAMI, AMANDA; BELLINI, MARIA H.Acute kidney injury (AKI) is an important health problem and can be caused by number of factors. The use of aminoglycosides, such as gentamicin, is one of these factors. Recently, an effort has been made to find biomarkers to guide treatment protocols. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the contents of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn in serum and urine of the healthy, AKI, and spontaneous recovery (SR) groups of animals. The animal model of AKI and SR was validated by measuring serum and urinary urea and creatinine. The quantitative determination of the elements showed a decrease in serum levels of Ca, and Fe in the AKI group (P<0.01 vs. healthy), with a return to normal levels in the SR group, without a significant difference between the healthy and SR groups. In the urine samples, there was a decrease in P and Na levels in the AKI group (P<0.001 and P<0.01 vs. healthy), but Ca levels were increased in this group compared with the healthy and SR groups (P<0.01). These findings indicate that mineral elements might be useful as biomarkers for AKI.Resumo IPEN-doc 23797 shRNA Knockdown of NFKB1 expression inhibits proliferation and promotes apoptosis of renal cell carcinoma2016 - IKEGAMI, A.; TEIXEIRA, L.F.; BRAGA, M.S.; SILVA, E.C. da; BELLINI, M.H.Renal cell carcinoma (RCC) represents approximately 2‐3 % of human malignancies. Despite all new therapeutic advances, almost all patients develop resistance to treatment and cure is rarely seen. The transcription factor KB (NFKB) comprises a family of transcription factors which has been associated with apoptosis resistance and progression of RCC. In this study, shRNA plasmid vector against NFKB1 gene was stably transduced into the Renca murine RCC cell line. Knockdown of NFKB1 was confirmed by quantitative real time PCR, Western blot and immunofluorescence analysis. The biological effects of decreased NFKB1 protein levels were evaluated, in vitro, by cell cycle and doubling time analysis and, in vivo, by tumor growth, cell proliferation (PCNA staining) and apoptosis (Caspase‐3 staining) and necrosis (morphometry). The results revealed that NFKB1 knockdown efficiently inhibited the growth of RencashRNA cells in culture, induced cell cycle arrest at the G2/M phase and led to a significant decrease of the doubling‐time. Moreover, NFKB1 shRNA vector suppressed tumor growth, enhanced apoptosis and necrosis compared with a wild type and mock control groups. In conclusion, our results suggest that specific silencing of NFKB is a potential therapeutic strategy for the treatment of RCC. This research was supported by FAPESP (2014/19265‐6)Resumo IPEN-doc 22980 A regulação negativa da expressão do gene NF-κβ1 induz a diminuição da proliferação em linhagem celular de carcinoma renal2016 - IKEGAMI, A.; TEIXEIRA, L.F.S.; BELLINI, M.H.Resumo IPEN-doc 22987 A regulação negativa da expressão do gene NF-κβ1 induz o retardamento da migração e invasão e redução da clonogenicidade em linhagem celular de carcinoma renal2016 - TEIXEIRA, L.F.S.; IKEGAMI, A.; BELLINI, M.H.Artigo IPEN-doc 22807 Evaluation of the applicability of Doppler velocimetry for monitoring acute kidney injury in rats2016 - SILVA, REGIANE M. da; KO, GUI M.; SANTOS, JOSE E.M.; BOIM, MIRIAN A.; IKEGAMI, AMANDA; BELLINI, MARIA H.Animal models of renal disease have been used in the study of pathogenesis and therapeutic protocols. In this study, doppler ultrasound was used to evaluate dysfunction in the renal vasculature in acute kidney injury in an animal model. Eight male Wistar rats received gentamicin (80 mg/kg) for 10 days. The blood urea and creatinine levels were measured to assess renal function. All doppler ultrasound measurements were performed on both kidneys and a colour map of the renal circulation was generated. Renal function and Doppler ultrasound measurements were performed 10 days before GM treatment and on the 5th and 10th days of the assay. Gentamicin treatment led to increased serum creatinine and blood urea levels at 5 days and 10 days post initial inoculation. A significant reduction in renal artery blood flow was observed after 5 days. However, these levels remained unchanged until the 10th day, demonstrating a lack of correlation with serum creatinine and blood urea levels. Therefore, the assessment of flow blood velocity of renal arteries by doppler ultrasound is not useful for monitoring acute kidney injury in rats.