Expression of the cell surface mucin gene family in adenocarcinomas

Cell surface mucins are complex glycoproteins expressed on the apical membrane surface of mucosal epithelial cells. In malignant epithelial cells they are thought to influence cell adhesion, and are clinical targets for tumor immunotherapy and serum tumor marker assays. We have compared expression of MUC1, MUC3, MUC4, MUC11, MUC12 and MUC13 mRNA in epithelial cancers and/or cell lines with non-malignant tissues. In non-malignant tissues, MUC3, 4, 11, 12 and 13 were expressed at highest levels in gastrointestinal tissues, whereas MUC1 was more widely distributed. Significant down-regulation of the MUC4, MUC12 and MUC13 genes was observed in colonic cancers compared with normal tissue, whereas MUC1 was upregulated. In rectal cancers, levels of all six mucin genes were not significantly different to those in normal rectal tissues. Both MUC1 and MUC4 were down-regulated in gastric cancers, whereas cancer and normal tissue levels were similar for MUC3, 11, 12 and 13. In esophageal cancers there was a general trend toward higher levels than in normal tissue for MUC1, 3, 12 and 13. In ovarian cancers MUC1 levels were very high, whereas only low levels of all other mucins were observed. We also report expression in renal cell carcinomas, bladder carcinomas and breast cancer cell lines. The reported expression profiles of the cell surface mucin gene family will help direct biological and clinical studies of these molecules in mucosal biology, and in malignant and inflammatory diseases of epithelial tissues.

Alpha-cellulose δ13C variation in mangrove tree rings correlates well with annual sea level trend between 1982 and 1999

A pilot study of tree rings in a modern mangrove tree (Rhizophora apiculata) from Leizhou Peninsula, northern South China Sea shows that ( 1) the tree-rings are annual; ( 2) the ring widths decrease; and ( 3) their alpha-cellulose delta(13)C values increase from 1982 to 1999 AD, consistent with the trends of annual sea level, salinity and sea surface temperatures in the same period. We propose that such changes were caused by increasingly longer duration of waterlogging in response to sea-level rise. If this is the case, alpha-cellulose delta(13)C in mangrove tree rings can be used as a potential indicator of past sea level fluctuations.