ABSTRACT
Biomarkers for early diagnosis of pancreatic cancer are greatly needed, as the high fatality of this cancer is in part due to delayed detection. α1,4-linked N-acetylglucosamine (αGlcNAc), a unique O-glycan specific to gastric gland mucus, is biosynthesized by α1,4-N-acetylglucosaminyltransferase (α4GnT) and primarily bound at the terminal glycosylated residue to scaffold protein MUC6. We previously reported that αGlcNAc expression decreases at early stages of neoplastic pancreatic lesions, followed by decreased MUC6 expression, although functional effects of these outcomes were unknown. Here, we ectopically expressed α4GnT, the αGlcNAc biosynthetic enzyme, together with MUC6 in the human pancreatic cancer cell lines MIA PaCa-2 and PANC-1, neither of which expresses α4GnT and MUC6. We observed significantly suppressed proliferation in both lines following coexpression of α4GnT and MUC6. Moreover, cellular motility decreased following MUC6 ectopic expression, an effect enhanced by cotransduction with α4GnT. MUC6 expression also attenuated invasiveness of both lines relative to controls, and this effect was also enhanced by additional α4GnT expression. We found αGlcNAc-bound MUC6 formed a complex with trefoil factor 2. Furthermore, analysis of survival curves of patients with pancreatic ductal adenocarcinoma using a gene expression database showed that samples marked by higher A4GNT or MUC6 mRNA levels were associated with relatively favorable prognosis. These results strongly suggest that αGlcNAc and MUC6 function as tumor suppressors in pancreatic cancer and that decreased expression of both may serve as a biomarker of tumor progression to pancreatic cancer.
Subject(s)
Acetylglucosamine/metabolism , Mucin-6/metabolism , Pancreatic Neoplasms/metabolism , Tumor Suppressor Proteins/metabolism , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Carcinoma, Pancreatic Ductal/genetics , Carcinoma, Pancreatic Ductal/metabolism , Carcinoma, Pancreatic Ductal/pathology , Cell Line, Tumor , Cell Movement , Cell Proliferation , Glycosylation , Humans , Mucin-6/genetics , N-Acetylglucosaminyltransferases/genetics , N-Acetylglucosaminyltransferases/metabolism , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Prognosis , RNA, Messenger/metabolism , Trefoil Factor-2/metabolism , Tumor Suppressor Proteins/geneticsABSTRACT
Simple and rapid methods for the detection of single nucleotide polymorphisms (SNPs) are required to analyze the genetic information. We have previously isolated DNA aptamers that bind to cholic acid by an in vitro selection method. A common feature of the sequences of the aptamers was that they included a secondary structure, a three-way junction, in which three stems were connected at the junction. It was also revealed that three-way junctions with fully matched three stems bind cholic acid whereas single-base substitutions at the junction lose binding affinity completely. Here we report a new method for the detection of single nucleotide mutations that is based on the formation of fully matched three-way junctions which bind to cholic acid.
Subject(s)
Aptamers, Nucleotide/chemistry , Cholic Acid/chemistry , DNA Mutational Analysis/methods , Polymorphism, Single Nucleotide , Nucleic Acid ConformationABSTRACT
We report a 29-year-old man with a rare left lumbar subcutaneous cold abscess complicated by tuberculous spondylitis during the treatment of pulmonary tuberculosis. Pulmonary tuberculosis was rapidly improved by anti-tuberculous drugs, however curative operation for tuberculous spondylitis was necessary after 18 months because tuberculous spondylitis was overlooked. Imaging techniques are important in helping to establish a diagnosis of tuberculous spondylitis. It should be stressed that a high clinical index of suspicion for tuberculosis is needed to correctly diagnose this disease.
