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Master's Dissertation
DOI
https://doi.org/10.11606/D.17.2021.tde-10052021-144137
Document
Author
Full name
Leticia Passi Turra
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2020
Supervisor
Committee
Tirapelli, Daniela Pretti da Cunha (President)
Borba, Luis Alencar Biurrum
Carneiro, Vinicius Marques
Peria, Fernanda Maris
Title in Portuguese
Expressão dos microRNAs miR-21 e miR-326 associada à regulação de HIF-1α em neuroesferas de glioblastomas submetidas ao tratamento com radiação ionizante
Keywords in Portuguese
Células-tronco tumorais
Glioblastoma
HIF-1α
miR-21
miR-326
Radiação ionizante
Abstract in Portuguese
INTRODUCÃO: O glioblastoma continua sendo uma neoplasia incurável, a partir dos protocolos terapêuticos bem estabelecidos, os mesmos proporcionam pouco aumento na sobrevida dos pacientes. O mecanismo de hipóxia associado às células-tronco tumorais (CSCs), com destaque à regulação da expressão de HIF-1α ou HIF-2α, está diretamente relacionado com o mau prognóstico em vários tipos de tumores. Estudos recentes também comprovam a regulação dos microRNAs em alvos moleculares diretamente envolvidos com a malignidade tumoral, como por exemplo, HIF-1α. OBJETIVO: Nosso objetivo foi analisar a expressão dos microRNAs miR-21 e miR-326 em neuroesferas de pacientes diagnosticados com glioblastoma tratadas com radiação ionizante. Esses microRNAs foram selecionados por apresentarem envolvimento comprovado com as CSCs e a regulação HIF-1α. METODOLOGIA: Neste trabalho, foram utilizadas culturas celulares de dez pacientes com glioblastoma a partir da biopsia intraoperatória. Avaliada a viabilidade celular com azul de Tripan após 48 horas de exposição à radiação ionizante, as expressões dos microRNAs supracitados foram analisados por PCR em tempo real. As expressões de miR-21 e miR-326 foram correlacionadas com óbito e recidiva mediante o grupo amostral, de forma geral e por grupo. A curva ROC identificou o ponto de corte dos respectivos microRNAs em relação ao prognóstico clínico, separando-os por grupo. RESULTADOS: Ao analisar a viabilidade celular, não foram identificadas diferenças estatísticas significativas entre neuroesferas nos grupos experimentais. Enquanto o miR-21 apresentou-se hiperexpresso no grupo de neuroesferas submetidas ao tratamento com radiação ionizante (p=0,0028), quando comparado ao grupo controle, contudo, não pode ser associado à recidiva e ao óbito. O miR-326 apresentou-se associado com a recidiva tumoral (p=0,032) em ambos os grupos, em que a cada 0,5 unidades de miR-326 o risco de recidivar aumenta 1,024 (2,4%). CONCLUSÃO: O miR-21 apresentou-se hiperexpresso no grupo de neuroesferas submetidas ao tratamento com radiação ionizante sugerindo que o seu papel na regulação de HIF-1α está relacionado às neuroesferas radiorresistentes. O miR-326 apresentou-se associado ao aumento de risco de recidivas em ambos os grupos, neuroesferas tratadas ou não com radiação ionizante, demonstrando também que esta regulação positiva independe do tratamento com radiação ionizante.
Title in English
Expression of microRNAs miR-21 and miR-326 associated with HIF-1α regulation in glioblastoma neurospheres submitted to ionizing radiation treatment
Keywords in English
Cancer stem cells
Glioblastoma
HIF-1α
Ionizing radiation
miR-21
miR-326
Abstract in English
INTRODUCTION: Gliobastoma continues being an incurable neoplasia, from well stablished therapeutical protocols, which do not offer much increasing on patients overliving. The hypoxia mechanism associated to cancer stem cells (CSCs), emphasizing the HIF-1α or HIF-2α expression regulation, is directly related to bad prognosis in many types of tumors. Recent studies also prove the microRNAs regulation in molecular targets directly involved with tumoral malignancy, such as HIF-1α, for example. OBJECTIVE: Our goal was to analyze microRNAs miR-21 and miR-326 expression in the neurospheres of patients diagnosed with gliobastoma and treated with ionizing radiation. These microRNAs were selected for presenting proved relation to the CSCs and HIF-1α regulation. METHODS: In this paper, cellular culture of ten patients with gliobastoma was used from surgery biopsies. The cellular viability was evaluated through Trypan Blue after 48 hours of ionizing radiation exposure, then, the aforementioned microRNAs expressions were analyzed through real time PCR. MiR-21 and miR-326 expressions were correlated to death and recurrence by means of the sample group, in general and per group. The ROC curve identified the cut point of the respective microRNAs in relation to the clinical prognosis, separating them by group. RESULTS: By analyzing cellular viability, significant statistical differences were not identified among the neurospheres in experimental groups. Meanwhile, miR-21 presented itself as hyperexpressed in the neurospheres group submitted to ionizing radiation treatment (p=0,0028), when compared to the control group, however, it could not be associated to recurrence and death. MiR-326 presented itself associated to tumoral recurrence (p=0,032) in both groups, in which every 0.5 units of miR-326 the chances of recurrence increase 1,024 (2,4%). CONCLUSIONS: MiR-21 presented itself hyperexpressed in neurospheres group submitted to ionizing radiation treatment suggesting that its role on HIF-1α regulation is related to radioresistant neurospheres. MiR-326 presented itself associated to the increasing chances of recurrence in both groups, neurospheres that were and were not treated though ionizing radiation, also demonstrating that this positive regulation does not depend on the ionizing radiation treatment.
 
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Publishing Date
2021-05-21
 
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