Levels of proteolytic activities as intermediate marker endpoints in oral carcinogenesis.

It is essential to identify intermediate marker endpoints of carcinogenesis for the evaluation of the effectiveness of cancer-chemopreventive agents. We have observed that levels of proteolytic activities (as detected by 4 different substrates) are increased 2-3-fold (P < 0.003) in oral buccal mucosa cells of smokers and patients with oral leukoplakia or erythroplakia as compared to a nonsmoking comparison group.

Monoclonal antibodies differentially reactive with native and reductively modified Bowman-Birk protease inhibitor.

Bowman-Birk protease inhibitor (BBI) is a potent anticarcinogen that suppresses malignant transformation at nanomolar concentrations. Small amounts of BBI in its native form can be measured by immunoassay using specific monoclonal antibodies (MAbs); however, the MAbs currently available are not capable of detecting BBI metabolites in human body fluids. To develop new reagents for the study of BBI exposure and pharmacokinetics, we produced four MAbs, designated 3B6, 3E3, 4H8 and 5G2, from hybridomas derived from a mouse immunized with reductively modified BBI.

The third component of Xenopus complement: cDNA cloning, structural and functional analysis, and evidence for an alternate C3 transcript.

Although the third component of complement has been purified from two amphibian species, Xenopus laevis and the axolotl, only limited information is available about its primary structure in these species. We now present (a) 95% of the cDNA sequence encoding C3 from a Xenopus laevis/Xenopus gilli (Xenopus LG) hybrid (b) an analysis of the C3 convertase and factor I cleavage sites in Xenopus C3, and (c) evidence for an alternative form of C3. The Xenopus LG sequence has a 57% nucleotide and 52% amino acid sequence identity to human C3 and contains one potential N-glycosylation site in the beta-chain.

Effects of protease inhibitors on levels of proteolytic activity in normal and premalignant cells and tissues.

Our studies utilizing different types of protease inhibitors as anticarcinogenic agents in in vivo and in vitro systems have recently been reviewed. These studies suggest that the protease inhibitors which prevent carcinogenesis affect processes in the early stages of carcinogenesis, although they can be effective at long time periods after carcinogen exposure in both in vitro and in vivo systems. While there is strong evidence that these protease inhibitors can affect both the initiation and promotion stages of carcinogenesis, they have no effect on already transformed cells.

Chromosomal assignment of a gene encoding a new collagen type (COL15A1) to 9q21 --> q22.

The collagens constitute a large family of extracellular matrix components primarily responsible for maintaining the structure and biological integrity of connective tissue. These proteins exhibit considerable diversity size, sequence, tissue distribution, and molecular composition. Fourteen types of homo- and/or heterotrimeric molecules, thus far reported, are encoded by a minimum of 27 genes.