Figure 1.

Activity, mRNA and protein levels of acylpeptide hydrolase (APEH), and proteasome correlate in a wide panel of cancer cells. Thirteen human cancer and two non-cancerous cell lines (BHK21, fibroblasts) were harvested at the pre-confluent stage and used for protein cytoplasmic or mRNA extract preparations. (A) Basal APEH and proteasomal CT-like (β5 subunit) specific activities were measured; (B) the mRNA levels of APEH and β5 proteasome subunit were evaluated by qPCR and reported as relative expression using the transcriptional levels in human fibroblast as control; (C) intracellular levels of β5 and APEH were detected by immunoblotting analysis. Data from three different analyses were normalized to the density of control protein (β-actin) and expressed as relative intensity. Results are presented as the mean values ± SD of triplicate analyses from at least three different experiments.