RESUMO
Copper-Cysteamine nanoparticles (Cu-Cy NPs) have emerged as promising radiosensitizers in cancer treatment. This study aims to investigate the combined therapeutic effect of these nanoparticles and cisplatin using a clinical linear accelerator to enhance the efficacy of chemoradiation therapy for cervical cancer. Following successful synthesis and characterization of Cu-Cy NPs, the cytotoxicity effect of these nanoparticles and cisplatin in various concentrations was evaluated on HeLa cancer cells, individually and in combination. Additionally, the radiobiological effects of these agents were investigated under a 6MV linear accelerator. At a concentration of 25 mg/L, Cu-Cy NPs displayed no significant cytotoxicity toward HeLa cancer cells. However, when combined with 2Gy X-ray irradiation at this concentration, the nanoparticles demonstrated a potent radiosensitizing effect. Notably, cell viability and migration rate in the combination group (Cu-Cy NPs + cisplatin + radiation) were significantly reduced compared to the radiation-alone group. Additionally, the combination treatment induced a significantly higher rate of apoptosis compared to the radiation-alone group. Overall, Cu-Cy NPs exhibited a significant dose-dependent synergistic enhancement of radiation efficacy when combined with cisplatin under X-ray exposure, and may provide a promising approach to improve the therapeutic effect of conventional radiation therapy.
RESUMO
Chondroitin Sulfate Proteoglycans (CSPGs) are the main inhibitors for axon regeneration after damaging of Central Nervous System (CNS). Chondroitinase ABC I (cABC I) can degrade CSPGs by removing chondroitin and dermatan sulfate side chains from proteoglycans. Hence, it may be considered as an attractive candidate in biomedicine. For practical applications of this enzyme, increasing the effective circulating level and reducing the number and volume of injections for patients is one of the main concerns which is directly related to conformational stability and catalytic efficiency of the enzyme. Structural examination of C-terminal domain of cABC I reveals that there are a few numbers of residues in helical conformation which are positioned at the context of a cohesive structural organization of ß-strands. In line with our previous studies on C-terminal domain of cABC I and regarding the residues in α-helix conformation; we designed and constructs some representative mutants including M889K, M889L, L679D/M889K and L679S/M889K. According to structural and functional characterization of protein variants and regarding the wide range of variability in determining parameters for ß-sheet conformation, we proposed a model in which the structural integrity of ß-strands at C-terminal domain can be manipulated and directed toward a new patterns of organization, some of them may have positive effects on the structural and functional features of the enzyme. Using this strategy it may be possible to improve functional and structural features of the enzyme by engineering the intra-molecular interactions in positions far from the active site of the enzyme.
