Search

Aims: Recent studies suggest that direct exposure of cells to fractionated radiotherapy might induce radioresistance. However, the effects of fractionated radiotherapy on the non-irradiated bystander cells remain unclear. We hypothesized that fractionated radiotherapy could enhance radioresistance and proliferation of bystander cells., Main Methods: Human tumor cell lines, including A549 and HT29 were irradiated (2 Gy per day). The irradiated cells (either A549 or HT29) were co-cultured with non-irradiated cells of the same line using transwell co-culture system. Tumor cell proliferation, radioresistance and apoptosis were measured using MTT assay, clonogenic survival assay and Annexin-V in bystander cells, respectively. In addition, activation of Chk1 (Ser 317), Chk2 (Thr 68) and Akt (Ser473) were measured via western blot., Key Findings: Irradiated HT29 cells induced conventional bystander effects detected as modulation of clonogenic survival parameters (decreased area under curve, D 10 and ED 50 and increased α) and proliferation in recipient neighbors. While, irradiated A549 cells significantly enhanced the radioresistance and proliferation of bystander cells. These changes were accompanied with enhanced activation of Chk1, Chk2 and Akt in non-irradiated bystander A549 cells. Moreover, both bystander effects (damaging and protective) were mediated through secreted factors., Significance: These findings suggest that fractionated radiotherapy could promote proliferation and radioresistance of bystander cells probably through survival and proliferation pathways., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Flavonoids have many biological properties, such as anticancer activity. Chalcones, one of their subunits, attribute their biological activity to their enone part. The presence of dinitrophenyl group in bischalcone because of its radiosensitivity property is important. Radiosensitivity property reduces radiation time in cancer patients and reduces damage to their healthy tissues. In this regard, 2,4-dinitrophenyl bischalcones were synthesized. The presence of 2,4-dinitrobenzaldehyde as a fixed component in synthesis pathway, leads to a reduction in yield of synthesis by common catalysts. Therefore, in this study, for bis-chalone synthesis, we used Graphene Oxide/Fe3O4/L-Proline nanocomposite as a green recoverable bifunctional organocatalyst. This catalyst was recovered simply by applying an external magnet and reused for eight runs. In this research, chalcones and asymmetric bis-chalcones have been synthesized with diverse substitutes in high yields (78–97%). Also, short reaction times (10–82 min), and simple experimental procedures with easy work-up are advantages of the introduced procedure. The synthesized compounds were characterized by melting point and analytical techniques. The chemical structures of synthesized compounds were confirmed by means of IR, 1HNMR, and 13CNMR. [ABSTRACT FROM AUTHOR]