Stat3 expression and its correlation with proliferation and apoptosis/autophagy in gliomas.
Signal transducer and activator of transcription-3 (Stat3) was studied along with several steps of the PI3/Akt pathway in a series of 64 gliomas that included both malignant and low-grade tumors, using quantitative immunohistochemistry, Western blotting, and molecular biology techniques. The goal of the study was to investigate whether activated Stat3 (phospho-Stat3) levels correlated with cell proliferation, apoptosis, and autophagy. Stat3 and activated Akt (phospho-Akt) expression increased with malignancy grade, but did not correlate with proliferation and survival within the category of glioblastomas. A correlation of Stat3 with Akt was found, indicating a regulation of the former by the PI3/Akt pathway, which, in turn, was in relation with EGFR amplification. Stat3 and Akt did not show any correlation with apoptosis, whereas they showed an inverse correlation with Beclin 1, a stimulator of autophagy, which was rarely positive in glioblastomas. Autophagy seems then to be inactivated in malignant gliomas.
Caldera
Valentina
V
Neuro-bio-oncology Center, Policlinico di Monza Foundation, University of Turin, Via Pietro Micca, 29, 13100 Vercelli, Italy.
Mellai
Marta
M
Annovazzi
Laura
L
Valente
Guido
G
Tessitore
Luciana
L
Schiffer
Davide
D