ABSTRACT
<p><b>OBJECTIVE</b>To analyze the distribution and significance of occludin mRNA expression in human gastric cancer, as well as its relationship with gastric cancer pathology and multidrug resistance (MDR) in vivo.</p><p><b>METHODS</b>In situ hybridization (ISH) technique was used to evaluate the expression of occludin mRNA in 42 gastric carcinoma specimens obtained by surgery and 23 relatively normal gastric mucosa obtained by gastric endoscopy. All specimens had been stored in cryostatic section.</p><p><b>RESULTS</b>Occludin mRNA was found positive in the cytoplasm of gastric glandulous epithelia as blue particles with intensive stain in 14 of 42 gastric carcinomas (33.3%), 23 of 42 paracancerous gastric tissues (54.8%), 14 of 23 relatively normal gastric tissues (60.9%), 9 of 16 well differentiated carcinomas (56.3%), 4 of 14 moderately differentiated carcinomas (28.6%), 1 of 10 poorly differentiated carcinomas (10.0%) and none of 2 mucosal carcinomas. There were significant differences in occludin mRNA positive rate between relatively normal gastric tissue and gastric cancer as well as between paracancerous gastric tissue and gastric cancer. The expression of occludin mRNA in moderately and poorly differentiated groups was gradually reduced when compared with well differentiated group, which suggests that there be a significant correlation between tumor differentiation and the expression of occludin mRNA. Furthermore, the positive signals of occludin mRNA distributed extensively in the cytoplasm of SGC7901/VCR cell, being vincristine resistant, derived from parental gastric cell line SGC7901. The positive signals of SGC7901/VCR were stronger than those of SGC7901 cells.</p><p><b>CONCLUSION</b>Occludin mRNA, being mainly located in epithelial cells and its expression correlated with tumor differentiation, may be involved in the development of multi-drug resistance in gastric cancer.</p>
Subject(s)
Humans , Drug Resistance, Multiple , Physiology , Drug Resistance, Neoplasm , Physiology , In Situ Hybridization , Membrane Proteins , Genetics , Metabolism , Occludin , RNA, Messenger , Metabolism , Stomach Neoplasms , Metabolism , Tight Junctions , MetabolismABSTRACT
Objective:To generate phage displayed anti idiotypic antibody single chain variable fragments(anti Id ScFv)to monoclonal antibody MC3 directed against colorectal carcinoma.Methods:Balb/c mice were immunized i.p. with MC3(McAb against colorectal Carcinoma) conjugated with KLH,and mRNA was isolated from the spleens of the immunized mice.VH and VL DNAs of the antibody were amplified separately and assembled into ScFv DNAs with a linker DNA by PCR.The ScFv DNAs were ligated into the phagemid vector pCANTAB5E and the ligated sample was transformed into competent E.coli TG1.The transformed cells were infected with M13KO7 helper phage to yield phage antibody ScFv library.After four rounds of panning to the library with MC3,the MC3 positive clones were selected by ELISA from the preselected phages.Results:The VH,VL and ScFv DNAs were about 340,320 and 750 bp respectively.After four rounds of panning to the antibody library,15 MC3 positive phage clones displayed anti Id ScFv were selected from 50 enriched phage clones.Conclusion:The phage displayed anti Id ScFv to MC3 were successfully selected by phage antibody library technology,which might provide new putative candidate molecules for developing recombinant anti Id vaccine of colorectal carcinoma.