Decreased expression of APAF-1 and increased expression of cathepsin B in invasive pituitary adenoma

Cristiana Tanase,1 Radu Albulescu,1,2 Elena Codrici,1 Bogdan Calenic,1,3 Ionela Daniela Popescu,1 Simona Mihai,1 Laura Necula,1,4 Maria Linda Cruceru,5 Mihail Eugen Hinescu1,5 1“Victor Babes” National Institute of Pathology, Biochemistry-Proteomics Department, 2National Institute for Chemical Pharmaceutical R&D, 3“Carol Davila” University of Medicine and Pharmacy, Department of Biochemistry, 4Stefan S. Nicolau Institute of Virology, Cellular and Molecular Pathology, 5“Carol Davila” University of Medicine and Pharmacy, Cellular and Molecular Medicine Department, Bucharest, Romania Purpose: Apoptotic protease-activating factor-1 (APAF-1) and cathepsin B are important functional proteins in apoptosis; the former is involved in the intrinsic (mitochondrial) pathway, while the latter is associated with both intrinsic and extrinsic pathways. Changes in the expression of apoptosome-related proteins could be useful indicators of tumor development since a priori defects in the mitochondrial pathway might facilitate the inception and progression of human neoplasms. Our aim was to evaluate the profiles of APAF-1 and cathepsin B in relation with other molecules involved in apoptosis/proliferation and to correlate them with the aggressive behavior of invasive pituitary adenomas. Materials and methods: APAF-1 and cathepsin B were assessed in tissue samples from 30patients with pituitary adenomas, of which 16 were functional adenomas and 22 were invasive adenomas. Results: A positive relationship between high proliferation and invasiveness was observed in invasive pituitary adenomas when compared to their noninvasive counterparts (Ki-67 labeling index – 4.72% versus 1.75%). Decreased expression of APAF-1 was recorded in most of the invasive adenomas with a high proliferation index, while the cathepsin B level was elevatedin this group. We have noticed a negative correlation between the low level of APAF-1 and invasiveness (63.63%; P