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PurposeTo investigate the effect of increasing the overall treatment time as well as delivering the compensating doses on the Balb/c breast adenocarcinoma (4T1) tumor. Materials and methodsA total of 72 mice were divided into two aliquots (classes A and B) based on the initial size of their induced tumor. Each class was divided into a control and several treatment groups. Among the treatment groups, group 1 was continuously exposed to 2 Gy irradiation, and groups 2 and 3 received two subfractions of 1 Gy over the total treatment times of 30 and 60 min, respectively. To investigate the effect of compensating doses, calculated based on the developed linear quadratic model (LQ) model, the remaining two groups (groups 4 and 5) received two subfractions of 1.16 and 1.24 Gy over the total treatment times of 30 and 60 min, respectively. The growing curves, Tumor Growth Time (TGT), Tumor Growth Delay Time (TGDT) and the survival of the animals were studied. ResultsFor class A (tumor size ≤ 30 mm3), the average tumor size in the irradiated groups 1–5 was considerably different compared to the control group as one unit (day) change in time, by amount of −160.8, −158.9, +39.4 and +44.0, respectively. While these amounts were +22.0, +17.9, −21.7 and −0.1 for class B (tumor size ≥ 400 mm3). For the class A of animals, the TGT and TGDT parameters were significantly lower (0 ≤ 0.05) for the groups 2 and 3, compared to group 1. There was no significant difference (p > 0.05) between groups 1, 4 and 5 in this class. There was no significant difference (p > 0.05) between all the treated groups in class B. ConclusionsIncreasing total treatment time affects the radiobiological efficiency of treatment especially in small-sized tumor. The compensating doses derived from the LQ model can be used to compensate the effects of prolonged treatment times atin vivocondition. [ABSTRACT FROM PUBLISHER]

In this research, we have synthesized guanidine functionalized PEGylated mesoporous silica nanoparticles as a novel and efficient drug delivery system (DDS). For this purpose, guanidine functionalized PEGylated I3ad mesoporous silica nanoparticle KIT-6 [Gu@PEGylated KIT-6] was utilized as a promising system for the effective delivery of curcumin into the breast cancer cells. The modified mesoporous silica nanoparticles (MSNs) was fully characterized by different techniques such as transmission and scanning electron microscopy (TEM & SEM), N2 adsorption-desorption measurement, thermal gravimetric analysis (TGA), X-ray powder diffraction (XRD), and dynamic light scattering (DLS). The average particle size of [Gu@PEGylated KIT-6] and curcumin loaded [Gu@PEGylated KIT-6] nanoparticles were about 60 and 70 nm, respectively. This new system exhibited high drug loading capacity, sustained drug release profile, and high and long term anticancer efficacy in human cancer cell lines. It showed pH-responsive controlled characteristics and highly programmed release of curcumin leading to the satisfactory results in in vitro breast cancer therapy. Our results depicted that the pure nanoparticles have no cytotoxicity against human breast adenocarcinoma cells (MCF-7), mouse breast cancer cells (4T1), and human mammary epithelial cells (MCF10A). [ABSTRACT FROM AUTHOR]

Herein, iron-gold core shell magnetic nanoparticles Fe@Au NPs was investigated as contrasting agent in radiation therapy in the breast cancer. Assessment of cytotoxic and radio sensitizing potential was done by MTT method and Flow cytometry. Radiation was done using Co 60 source. The response of cells to treatment with radiation alone and radiation with nanoparticles was assessed. The study demonstrates that Fe@Au nanoparticles do not have considerable cytotoxic effects, but they increase the effectiveness of radiation that means the survival of the group without nanoparticles exposed to 5 Gy radiations is 75%while the group with nanoparticles is 33%. With 2 Gy radiations the survival of the two groups are 87% and 80% respectively. [ABSTRACT FROM AUTHOR]