Reverse-Phase Protein Array Analysis to Identify Biomarker Proteins in Human Pancreatic Cancer

Abstract

Background Pancreatic cancer is the fourth leading cause of cancer death in the U.S. The high mortality rate of patients with pancreatic cancer is primarily due to the difficulty of early diagnosis and a lack of effective therapies. There is an urgent need to discover novel molecular targets for early diagnosis and new therapeutic approaches to improve the clinical outcome of this deadly disease. Aim we utilized the reverse-phase protein assay (RPPA) to identify differentially expressed biomarker proteins in tumors and matched adjacent, normal-appearing tissue samples from 15 pancreatic cancer patients. Methods The antibody panel used for the RPPA included 130 key proteins involved in various cancer-related pathways. The paired t test was used to determine the significant differences between matched pairs, and the false discovery rate-adjusted p values were calculated to take into account the effect of multiple comparisons. Results After correcting for multiple comparisons, we found 19 proteins that had statistically significant differences in expression between matched pairs. However, only four (AKT, β-catenin, GAB2, and PAI-1) of them met the conservative criteria (both a q value <0.05 and a fold-change of ≥ 3/2 or ≤ 2/3) to be considered differentially expressed. Overexpression of AKT, β-catenin, and GAB2 in pancreatic cancer tissues identified by RPPA has also been further confirmed by western blot analysis. Further analysis identified several significantly associated canonical pathways and overrepresented network functions. Conclusion GAB2, a newly identified protein in pancreatic cancer, may provide additional insight into this cancer’s pathogenesis. Future studies in a larger population are warranted to further confirm our results.

Distribution of Cholecystokinin-B Receptor Genotype Between Patients With Pancreatic Cancer and Controls and Its Impact on Survival

“…43 In a large pancreatic cancer GWAS analysis, Wei and coworkers 44 screened a database of over 3,000 pancreatic cancer patients and consistently found that the G-protein coupled receptor signaling pathway was the most significant pathway to predict pancreatic cancer risk. Huang et al, 45 found that the AKT signaling protein was significantly over-expressed in pancreatic cancer compared to noncancerous tissues using reverse phase protein array. Indeed, we previously demonstrated that growth of pancreatic cancer is regulated by the over-expression of this GPCR, CCK-BR 21 and that down regulation of the CCK-BR in pancreatic cancer cells results in apoptosis and halts cell proliferation 22 by interference with intracellular signaling and decreased AKT phosphorylation.…”

Hypoxia promotes chemoresistance in acute lymphoblastic leukemia cell lines by modulating death signaling pathways

“…The RPPA method allows the measurement of protein expression levels and their post-translational states (cleavage, phosphorylation, ubiquitination) in a low volume of sample. RPPA has already been used to demonstrate the importance of several proteins and their post-translational modification in tumorogenesis [ 18 , 19 ].…”

Dynamic system explanation

“…As previously discussed [8], reverse phase protein arrays discovered that GAB2, AKT, β-catenin and PAI-1 were overexpressed in pancreatic cancer [21]. In order to find articles with information about the proteins under investigation, queries are formulated with protein synonyms and aliases using logical notation.…”