Avaliação da expressão gênica do receptor A2A e do PTEN em tecidos humanos de glioblastomas e gliomas não glioblastomas por qRT-PCR

Abstract

Introduction: Gliomas and glioblastomas are malignant tumors that present complex treatment challenges and are associated with low survival rates. The presence of cancer in the Central Nervous System (CNS) increases adenosine levels and A2A receptor expression, while decreasing the expression levels of the tumor suppressor gene Phosphatase and TENsin homolog (PTEN), primarily through mutations. Objective: To characterize the profile of the participants and analyze the mRNA expression levels of the A2A receptor and PTEN in tissue samples from patients with non-GBM gliomas and glioblastomas. Methods: This is a quantitative, cross-sectional study conducted with 32 glioma patients, divided into two groups: non-GBM gliomas and glioblastomas. Participant profiles were characterized based on medical records provided by the attending neurosurgery team, with all patients having signed an informed consent form. The relative mRNA expression of A2A and PTEN in tumor cells obtained from participants was analyzed using quantitative real-time PCR (qRT-PCR) performed by the authors. Results and Discussion: It was found that 90% of patients with non-GBM gliomas were under 50 years old, while 100% of glioblastoma patients were over 50, moreover 70% of the glioma samples are grade 2. The mRNA expression of the A2A receptor, as measured by qRT-PCR, was significantly higher in the non-GBM glioma group compared to the glioblastoma group. Similarly, the relative mRNA expression of PTEN was significantly reduced in the glioblastoma group compared to the non-GBM glioma group. There are few studies in the literature addressing the specific role of A2A in glioblastomas or making direct comparisons with lower-grade gliomas. It is known that A2A overexpression occurs during tumor development and contributes to its progression. However, the higher mRNA expression levels observed in grade II and III gliomas compared to glioblastomas suggest the need for further research into the role of this receptor in high-grade tumors. On the other hand, the reduced PTEN expression in glioblastomas is consistent with findings widely reported in the literature. Mutations in the PTEN gene impair its tumor-suppressive function, enabling malignant progression. In glioblastomas, PTEN is frequently suppressed or mutated, making it the second most common tumor type for this alteration. Furthermore, reduced PTEN protein expression is associated with lower survival rates, as seen in GBM patients, with up to 90% dying within the first two years after diagnosis.