A peptide array-based serological protein kinase A activity assay and its application in cancer diagnosis

Abstract

Protein kinase A (PKA) plays a crucial role in several biological processes; however, there is no assay with sufficient sensitivity and specificity to determine serological PKA (sPKA) activity. Here we present an on-chip activity assay that employs cysteine-modified kemptide arrays to determine specific sPKA activity in human sera that eliminates the potential contributions of other kinases with a protein kinase peptide inhibitor. The sensitivity of the on-chip sPKA activity assay was greatly enhanced by Triton X-100, with a 0.01 U mL(-1) detection limit. sPKA activity was determined by subtracting nonspecific sPK activity from total sPK activity. Our assay provided greater sensitivity and specificity and more accurate area under the curve values for gastric cancer compared to the total sPK activity assay. sPKA activities in human sera from patients with hepatic (n = 30), gastric (n = 30), lung (n = 30), and colorectal (n = 30) cancers were significantly higher than those in controls (n = 30, p < 10(-4)), but no significant difference in sPKA activities between normal and inflammation groups was observed. These results demonstrate that the on-chip assay accurately measures sPKA activity in human sera and that the sPKA activity may be a potential biomarker for cancer diagnosis.

Preventive Effects of Thermosensitive Biopolymer‐Conjugated C‐Peptide against High Glucose‐Induced Endothelial Cell Dysfunction

“…Amine‐modified glass slides were prepared as previously reported . Briefly, glass slides (75 mm × 25 mm) were cleaned with a H 2 O 2 /NH 4 OH/H 2 O (1:1:5, v/v) solution, immersed in 95% ethanol with 1.5% (v/v) 3‐aminopropyltrimethoxysilane for 2 h, and baked overnight at 110 °C.…”

Opportunities and Challenges of Kava in Lung Cancer Prevention

“…Indeed, PKA was identified as the key driver oncoprotein via un-biased global profiling in multiple studies [126,127]. Second, the systemic levels of PRKACA have been observed to be elevated in patients of various types of cancers, including lung cancer, and thus PRKACA in blood has been proposed as a potential cancer biomarker [128][129][130][131][132]. Third, PKA activation has been reported to induce anxiety in multiple animal models as well [133][134][135][136] while kava is well-known for its anxiolytic (anti-anxiety) property [91].…”

Identification of transglutaminase 2 kinase substrates using a novel on-chip activity assay

“…Amine-modified glass slides were prepared according to the procedures of Kong et al (Kong et al, 2015). Briefly, glass slides (75 Â 25 mm) were cleaned with a H 2 O 2 /NH 4 OH/H 2 O (1:1:5, v/v) solution, immersed in 95% ethanol solution with 1.5% 3-aminopropyltrimethoxysilane (v/v) for 2 h, and baked overnight at 110°C.…”