Avaliação da inibição de FAK na sobrevivência e na interação FAK/ αB-cristalina em células de glioblastoma

Abstract

Cancer is one of the major public health problems globally, representing one of the leading causes of death and a barrier to increasing life expectancy. Among tumors of the Central Ner- vous System (CNS), Glioblastoma Multiforme (GBM) stands out as the most aggressive and prevalent subtype, being the most common primary malignant brain tumor in adults and hav- ing the worst prognosis, with an average survival of around 15 months. Standard treatment consists of wide surgical resection followed by radiotherapy and adjuvant chemotherapy with temozolomide (TMZ). However, GBM is characterized by high therapeutic resistance, fre- quently associated with genetic and epigenetic mechanisms. Given this, the search for new, more effective and less harmful therapeutic strategies becomes fundamental. In this context, proteins such as Focal Adhesion Kinase (FAK) and αβ-Crystallin, involved in cell survival, proliferation and migration processes, whose higher expression has been associated with tu- mor progression and unfavorable prognosis in different types of cancer, emerge as relevant targets for study. Previous studies by our group have demonstrated that the interaction be- tween FAK/αB-crystalline is important for the survival of different cell types such as cardiac myocytes and glioblastoma. Thus, the present work aimed to evaluate the effects of inhibiting FAK phosphorylation on the viability of glioblastoma cells, as well as to investigate the effect of this inhibition on the interaction between FAK/αB-crystalline proteins. T98G glioblastoma cell lines were cultured and treated with the FAK inhibitor PF-562.271, and subsequently sub- jected to cell viability assays (MTT), Western blotting, and co-immunoprecipitation. The re- sults showed that after 24 hours of treatment with the FAK inhibitor, concentrations of 200 μM and 400 μM reduced cell viability by 30% and 58%, respectively. Based on these data, the 200 μM concentration was selected for subsequent experiments. Western blotting assays revealed that the treatment decreased FAK phosphorylation by approximately 98%, with no detectable changes in αβ-crystallin expression. The interaction between FAK and αβ-crys- tallin, assessed by co-immunoprecipitation, occurred independently of the FAK phosphoryla- tion status, but showed a significant increase after treatment with PF-562.271. Taken together, the findings indicate that the FAK/αB-Crystallin interaction occurs more significantly in the non-phosphorylated state of FAK and that inhibition of FAK phosphorylation was able to pro- mote the death of glioblastoma cells. Further assays will be needed to verify the effect that the FAK/αB-Crystallin interaction has on cells treated with PF-562.271.