Abstract
BackgroundThe development of novel targeted cancer therapies and/or diagnostic tools is dependent upon an understanding of the differential expression of molecular targets between normal tissues and tumors. Many of these potential targets are cell-surface receptors; however, our knowledge of the cell-surface proteins upregulated in pancreatic tumors is limited, thus impeding the development of targeted therapies for pancreatic cancer. To develop new diagnostic and therapeutic tools to specifically target pancreatic tumors, we sought to identify cell-surface proteins that may serve as potential tumor-specfic targets.MethodsMembrane glycoproteins on the pancreatic cancer cell lines BxPC-3 were labeled with the bifunctional linker biocytin hydrazide. Following proteolytic digestion, biotinylated glycopeptides were captured with streptavidin-coupled beads then released by PNGaseF-mediated endoglycosidase cleavage and identified by liquid chromatography-tandem mass spectrometry (MS). A protein identified by the cell-surface glycoprotein capture procedure, CD109, was evaluated by western analysis of lysates of pancreatic cancer cell lines and by immunohistochemistry in sections of pancreatic ductal adenocarcinoma and non- neoplastic pancreatic tissues.ResultsMS/MS analysis of glycopeptides captured from BxPC-3 cells revealed 18 proteins predicted or known to be associated with the plasma membrane, including CD109, which has not been reported in pancreatic cancer. Western analysis of CD109 in lysates prepared from pancreatic cancer cell lines revealed it was expressed in 6 of 8 cell lines, with a high level of expression in BxPC-3, MIAPaCa-2, and Panc-1 cells. Immunohistochemical analyses of human pancreatic tissues indicate CD109 is significantly overexpressed in pancreatic tumors compared to normal pancreas.ConclusionsThe selective capture of glycopeptides from the surface of pancreatic cancer cell lines can reveal novel cell-surface glycoproteins expressed in pancreatic ductal adenocarcinomas.
Highlights
Pancreatic cancer is the fourth most common cause of cancer-related deaths in the United States [1], and is projected to be the second leading cause of cancer-related death by 2030 [2]
The selective capture of glycopeptides from the surface of pancreatic cancer cell lines can reveal novel cell-surface glycoproteins expressed in pancreatic ductal adenocarcinomas
As expected for glycoproteins labeled with biocytin in the cell-surface capture (CSC) procedure, most of the peptides identified by mass spectrometry (MS) from these proteins contain an NXS/T T motif
Summary
Pancreatic cancer is the fourth most common cause of cancer-related deaths in the United States [1], and is projected to be the second leading cause of cancer-related death by 2030 [2]. Targeted therapies may be used to 1) block the proliferation of cancer cells by interfering with specific molecules required for tumor development and growth, 2) enhance antibody-dependent cellular and complement-dependent cytotoxicity, or 3) facilitate delivery of novel nanoparticle conjugates to tumor cells Some of these targeting molecules may be present in normal tissues, but they are often mutated or overexpressed in tumors. The development of novel targeted cancer therapies and/or diagnostic tools is dependent upon an understanding of the differential expression of molecular targets between normal tissues and tumors Many of these potential targets are cell-surface receptors; our knowledge of the cell-surface proteins upregulated in pancreatic tumors is limited, impeding the development of targeted therapies for pancreatic cancer. To develop new diagnostic and therapeutic tools to target pancreatic tumors, we sought to identify cell-surface proteins that may serve as potential tumor-specfic targets
Sign-in/Register to view highlights & summary 
Accepted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call