Definition of a new cut-off for the anti-phospholipase A2 receptor (PLA2R) autoantibody immunoassay in patients affected by idiopathic membranous nephropathy.

Autoantibodies against phospholipase A2 receptor (PLA2R) are a sensitive and specific marker for idiopathic membranous nephropathy (IMN). The aim of our study was to redefine the cut-off value for the measurement of anti-PLA2R autoantibody levels by an automated enzyme immunoassay, in a large single-center cohort of Italian IMN patients at the time of diagnosis. Sixty-seven consecutive incident patients, with biopsy-proven IMN, were recruited. All patients were naïve to preceding immunosuppressive therapeutic regimens. The patient population had a mean age of 57 years and included 48 males and 19 females. Also, 200 patients with other renal diseases and 36 healthy subjects were studied as controls. The anti-PLA2R autoantibody levels were measured using the commercial enzyme-linked immunosorbent assay kit at the time of renal biopsy. At a cut-off value of 2.7 RU/ml (significantly lower than the manufacturer's recommended value of 14 RU/ml), calculated by receiver operating characteristic curves, the sensitivity and specificity of anti-PLA2R autoantibodies in the diagnosis of IMN was 88.1 and 96% respectively. The adapted cut-off value of 2.7 UI/ml increased sensitivity without affecting the specificity and it should be the recommended value for this method. Additionally our study confirmed the correlation, at baseline, between anti-PLA2R autoantibody levels and other biomarkers of disease activity.

The inhibition of p85αPI3KSer83 phosphorylation prevents cell proliferation and invasion in prostate cancer cells.

Phosphoinositide 3-kinase proteins are composed by a catalytic p110 subunit and a regulatory p85 subunit. There are three classes of PI3K, named class I-III, on the bases of the protein domain constituting and determining their specificity. The first one is the best characterized and includes a number of key elements for the integration of different cellular signals. Regulatory p85 subunit shares with the catalytic p110 subunit, a N-terminal SH3 domain showing homology with the protein domain Rho-GTP-ase. After cell stimulation, all class I PI3Ks are recruited to the inner face of the plasma membrane, where they generate phosphatidylinositol-3,4,5-trisphosphate by direct phosphorylation of phosphatidylinositol-4,5-bisphosphate. All pathways trigger the control of different phenomena such as cell growth, proliferation, apoptosis, adhesion and migration through various downstream effectors. We have previously provided direct evidences that a Serine in position 83, adjacent to the N-terminal SH3 domain of regulatory subunit of PI3K, is a substrate of PKA. The aim of this work is to confirm the role of p85αPI3KSer83 in regulating cell proliferation, migration and invasion in prostate cancer cells LNCaP. To this purpose cells were transfected with mutant forms of p85, where Serine was replaced by Alanine, where phosphorylation is prevented, or Aspartic Acid, to mimic the phosphorylated residue. The findings of this study suggest that identifying a peptide mimicking the sequence adjacent to Ser 83 may be used to produce antibodies against this residue that can be proposed as usefool tool for prognosis by correlating phosphorylation at Ser83 with tumor stage.