Related Experiment Videos
Internalisation of the Bowman-Birk protease inhibitor by intestinal epithelial cells
P C Billings1, D L Brandon, J M Habres
1Department of Radiation Oncology, University of Pennsylvania School of Medicine, Philadelphia 19104.
Abstract:
Protease inhibitors have been shown to be effective suppressors of carcinogenesis in vitro and in vivo. For example, the soybean-derived Bowman-Birk inhibitor (BBI) suppresses dimethylhydrazine-induced colon carcinogenesis in mice. Relatively little is known about the effects of protease inhibitors on intestinal epithelial cells. In the present study, we have investigated the interaction of the anticarcinogenic BBI with intestinal epithelial cells. At the concentrations examined, BBI was non-toxic and had no effect on the doubling time, saturation density or rate of DNA synthesis by these cells. This compound was taken up by these cells in a time dependent manner and was present in the cells for 12 h following a 2 h incubation with BBI. Subcellular fractionation experiments demonstrated that the bulk of the internalised inhibitor was present in the cytosol. Analysis of BBI from treated cells on a chymotrypsin affinity column revealed that active inhibitor was present in the cells. Our results indicate that the BBI is internalised by colonic epithelial cells which would allow BBI to inhibit critical intracellular proteases and thus suppress malignant transformation.
Insights
Soybean-derived Bowman-Birk inhibitor (BBI) is internalized by colon cells without toxicity. This suggests BBI can inhibit intracellular proteases, potentially suppressing colon cancer development.
Area of Science:
- Biochemistry
- Cell Biology
- Cancer Research
Background:
- Protease inhibitors demonstrate efficacy in suppressing carcinogenesis.
- Soybean Bowman-Birk inhibitor (BBI) shows promise in preclinical cancer models.
- Limited understanding exists regarding protease inhibitor interactions with intestinal epithelial cells.
Purpose of the Study:
- To investigate the interaction between the anticarcinogenic Bowman-Birk inhibitor (BBI) and intestinal epithelial cells.
- To determine the cellular uptake, localization, and activity of BBI in these cells.
Main Methods:
- Cellular assays to assess BBI toxicity, proliferation, and DNA synthesis.
- Time-dependent uptake studies and subcellular fractionation.
- Chymotrypsin affinity chromatography to confirm active BBI presence.
Main Results:
- BBI was non-toxic to intestinal epithelial cells at tested concentrations.
- BBI exhibited time-dependent cellular uptake, persisting for at least 12 hours.
- Internalized BBI was primarily localized in the cytosol and remained active.
Conclusions:
- Bowman-Birk inhibitor (BBI) is effectively internalized by colonic epithelial cells.
- Internalization allows BBI to access and inhibit intracellular proteases.
- This mechanism supports BBI's potential role in suppressing malignant transformation and colon cancer.