Razi Journal of Medical Sciences

    Background & Aim: In vitro experiments and in vivo studies have revealed that radiosensitizers in radiation therapy may serve as powerful tools in the treatment of glioma cancers. Many cell lines, under some specific conditions will aggregate and grow to form multicellular structures called spheroid. Thses spheroids resemble in vivo tumor models in several aspects. Therefore studying growth characteristics and behavior of spheroids is beneficial in understanding the behavior of tumors under various experimental conditions. The aim of the current study was to determine the role of Iudr(Iododeoxyuridine) in sensitizing glioma cell line spheroids to radiation. Material and Methods: This study is an experimental research and T-test was used to compare the results. In this study we compared the DNA induced damages in U87MG cell line using alkaline comet assay method. Experiments were performed with two different sizes of spheroids(100µm and 300 µm). Results: Our results showed the effect of radiation on both diameters of spheres in the presence and absence of Iudr. Accordiology radiation in the presence of Iudr increased the tail moment and thus increased cellular damage. Iudr, in saturation concentration increases the cells radiosensitivity. Specifically in 300µm spheroids, in the presence of Iudr, cell damage was increased to 50%. Conclusion: Comparison of tail moments in spheroids with 100 and 300µm diameter showed that cell damages in larger spheroids(300µm) are lesser than smaller ones(100µm). It may be because of existence of G0 cells and cells with longer cycles, in which Iudr is incorporated to a lesser extent into them. Also, our results showed that minimum presence of Iudr increased the cells radiosensitivity. Therefore inorder to increase the efficacy of this modality of treatmnt we can increase the incubation time of Iudr, increasing the cell population in the cell cycle. In addition cells with longer cycles have more time to incorporate Iudr, or we can use agents that inhibit repairing.