Cell-Based Assay System to Estimate the Effect of 125I Seeds on Cancer Cells: Effect of Osteopontin

Background and Purpose: A number of recent patents related to 125I seed and osteopontin have been awarded. In this study, we developed a new in vitro model to study the radiobiological effects of 125I seeds on cancer cells. Methods: We placed 125I seeds in a cell culture plate with cells seeded on a transwell chamber to evaluate the effects of 125I seeds on cell motility. We placed 125I seeds in a transwell chamber with cells seeded on the cell culture plate to study cell proliferation, apoptosis, and to perform western blot. Results: We used SK-Hep-1 liver cancer cells to evaluate the effectiveness of our model, and investigated the role of osteopontin in the therapeutic effects of 125I seeds. We found that 125I seeds inhibited the cell proliferation and motility in this model while osteopontin reduced these effects. We also measured the effects of 125I seeds on apoptosis. Furthermore, when treated with 125I seeds, we detected changes in several signaling pathways that are involved in the proliferation and invasion of cancer cells. Conclusions: The model can be used to assess the biological effects of 125I seeds in vitro. Osteopontin may be involved in the 125I seed-induced inhibition of SK-Hep-1 cells.