Methoxyamine enhances 5-fluorouracil-induced radiosensitization in colon cancer cell line HT29

Objective: This study intended to observe the effects of methoxyamine [Mx] on cytotoxic effects and DNA damage caused by 5-Fluorouracil [5-FU] in combination with gamma radiation in a human colon cancer cell line, HT29

Materials and Methods: In this experimental study, HT29 cells were cultured as a monolayer and treated with different concentrations of 5-FU along with 1 mM Mx for 24 hours. Next, the cells were irradiated with 2 Gy gamma radiation. After the treatments, we assessed for DNA damage, cytotoxicity, and viability by alkaline comet, clonogenic survival, and trypan blue dye exclusion assays

Results: Cytotoxicity and DNA damage increased with increasing 5-FU concentration. The 1 mM Mx concentration had no significant effect on cytotoxicity and DNA damage from 5-FU; however, it increased the cytotoxic and genotoxic effects of different concentrations of 5-FU when used in combination with 2 Gy gamma radiation

Conclusion: Mx combined with 5-FU enhanced the radiosensitivity of colon cancer cells

Enhanced DNA damages of human prostate cancer cells induced by radiofrequency capacitive hyperthermia pre- and post X-rays: 6 MV versus 15 MV

Objective: This study aimed to determine the effect of 13.56 MHz radiofrequency [RF] capacitive hyperthermia [HT] on radiosensivity of human prostate cancer cells pre and post X-ray radiation treatment [RT]

Materials and Methods: In this experimental study, the human prostate cancer cell line DU145 was cultured as 300 micro m diameter spheroids. We divided the spheroids into group I: control, group II: HT at 43[degree]C for 30 minutes [HT], group III: 4 Gy irradiation with 6 MV X-ray [RT [6 MV]], group IV: 4 Gy irradiation with 15 MV X-ray [RT [15 MV]], group V: HT+RT [6 MV], group VI: HT+RT [15 MV], group VII: RT [6 MV]+HT, and group VIII: RT [15 MV]+HT. The alkaline comet assay was used to assess DNA damages in terms of tail moment [TM]. Thermal enhancement factor [TEF] was obtained for the different treatment combinations

Results: Mean TM increased with increasing photon energy. Group II had significantly greater TM compared to group I. Groups III and IV also had significantly higher TM compared to group I. Significant differences in TM existed between groups V, VII, and III [P<0.05]. We observed significant differences in TM between groups VI, VIII, and IV. TEF values demonstrated that enhanced response to radiation was more pronounced in group V compared to the other combined treatments

Conclusion: Our results suggest that HT applied before RT leads to higher radiosensivity compared to after RT. HT at 43[degree]C for 30 minutes added to 6 MV X-ray causes higher enhancement of radiation compared to 15 MV X-ray

role of radiofrequency hyperthermia in the radiosensitization of a human prostate cancer cell line

Objective: This study evaluated enhanced induced DNA damages and apoptosis of a spheroid culture of DU145 prostate cancer cells treated by a combination of radiofrequency hyperthermia [RF HT] with radiation treatment [RT] from an external radiotherapy machine compared to RT alone

Materials and Methods: In this experimental study, DU145 cells were cultured as spheroids until they reached 300 micro m in diameter. We exposed these cultures to either: RF HT for 90 minutes at 43[degree]C originated from a Celsius TCS system, RF HT followed by RT at doses of 2 Gy or 4 Gy [15 MV energy] with 15-minute interval, or RT alone at the above mentioned doses. The trypan blue exclusion assay, alkaline comet assay, and annexin V/PI flow cytometry were performed to measure cell viability, the amount of DNA damage in an individual cell as the tail moment, and percentage of induced cell apoptosis in response to treatments explained

Results: We calculated the thermal enhancement factor [TEF] for the combined treatment regime. RF HT followed by the 4 Gy dose of RT resulted in minimum viability [85.33 +/- 1.30%], the highest tail moment [1.98 +/- 0.18], and highest percentage of apoptotic cells [64.48 +/- 3.40%] compared to the other treatments. The results of the TEF assay were 2.54 from the comet assay and 2.33 according to flow cytometry

Conclusion: The present data suggest that combined treatment of mega voltage X-rays and RF HT can result in significant radiosensitization of prostate cancer cells

Magnetic resonance imaging of human-derived amniotic membrane stem cells using PEGylated superparamagnetic iron oxide nanoparticles

Objective: the label and detection of cells injected into target tissues is an area of focus for researchers. Iron oxide nanoparticles can be used to label cells as they have special characteristics. The purpose of this study is to examine the effects of iron oxide nanoparticles on human-derived amniotic membrane stem cell [hAMCs] survival and to investigate the magnetic properties of these nanoparticles with increased contrast in magnetic reso-nance imaging [MRI]

Materials and Methods: in this experimental study, we initially isolated mesenchymal stem cells from amniotic membranes and analyzed them by flow cytometry. In addition, we synthesized superparamagnetic iron oxide nanoparticles [SPIONs] and characterized them by various methods. The SPIONs were incubated with hAMCs at concentrations of 25-800 [micro]g/mL. The cytotoxicity of nanoparticles on hAMCs was measured by the MTT assay. Next, we evaluated the effectiveness of the magnetic nanoparticles as MRI contrast agents. Solutions of SPION were prepared in water at different iron concentrations for relaxivity measurements by a 1.5 Tesla clinical MRI instrument

Results: the isolated cells showed an adherent spindle shaped morphology. Polyethylene glycol [PEG]-coated SPIONs exhibited a spherical morphology. The average particle size was 20 nm and magnetic saturation was 60 emu/g. Data analysis showed no significant reduction in the percentage of viable cells [97.86 +/- 0.41%] after 72 hours at the 125 [micro]g/ml concentration compared with the control. The relaxometry results of this SPION showed a transverse relaxivity of 6.966 [[micro]g/ml.s][-1]

Conclusion: SPIONs coated with PEG used in this study at suitable concentrations had excellent labeling efficiency and biocompatibility for hAMCs

effect of quercetin and hyperthermia on spheroid model of DU145 prostate carcinoma cell line

The purpose of this study is to investigate the effects of Quercetin as an inhibitor of heat shock proteins and hyperthermia on the induced DNA damages and colony formation ability of DU145 tumor spheroid culture. DU145 cells were cultured as spheroids. On day11, spheroids with mean diameter 100 ?m were treated with different concentration of Quercetin for 24 hours and then exposed to hyperthermia at 43oC for 1 hour. After heat exposure, the colony forming ability and the induced DNA damages were examined using colonogenic and alkaline comet assay methods, respectively. Our results showed that DMSO diluent in combination with hyperthermia had no significant effect on the number of colonies and the level of DNA damages as compared to control [p>0.05]. Furthermore, number of colonies decreased and DNA damages increased by increasing Quercetin concentration in combined treatment of DU145 cells with Quercetin and hyperthermia in spheroid cultures. Quercetin as an inhibitor of heat shock protein 70 production in cells exposed to hyperthermia can increase DNA damages and decrease colony numbers of the prostate cancer cells in a dose-dependent manner and there is a correlation between the increase of DNA damages and decrease of colony numbers

Evaluation of the combined effect of 2ME2 and 60Co on the inducement of DNA damage by IUdR in a spheroid model of the U87MG glioblastoma cancer cell line using alkaline comet assay

In this study, we investigated the combined effect of 2-Methoxyestradiol [2ME2] and 60Co on the cytogenetic damage of iododeoxyuridine [IUdR] in the spheroid model of U87MG glioblastoma cancer cell lines by alkaline comet assay. U87MG cells were cultured as spheroids with diameters of 350 micro m. As control, the spheroids of one plate were not treated. Other cultures were pretreated with 2ME2 [250 micro M] for one volume doubling time [1 VDT]. After this time, the subsequent treatments were performed according to the following groups: 1. Vehicle [this sample was not treated in the 2nd VDT] 2. Treated with 2ME2 [250 micro M] for 1 VDT 3. Treated simultaneously with 2ME2 [250 micro M] and IUdR [1 micro M] for 1 VDT 4. Treated with 2ME2 [250 micro M] for 1 VDT then irradiated with 60Co [2 Gy] 5. Treated simultaneously with 2ME2 [250 micro M] and IUdR [1 micro M] for 1 VDT then irradiated with 60Co [2 Gy] Then the DNA damage was evaluated using the alkaline comet assay method. The results showed that 2ME2 in combination with gamma irradiation of 60Co significantly [p<0.001] increased the DNA damage by IUdR as compared to the control group. Thus the combination of these two agents increased the cytogenetic effects of IUdR in the spheroid culture model of U87MG glioblastoma cell lines. By inhibiting the HIF-1 protein and preventing the G0 phase arrest, 2ME2 causes an increased progression into S phase and increases the IUdR absorption. Then the DNA damage in the spheroid cells increases as the uptake of IUdR is increased. These results suggest that the combined use of 2ME2 and 60Co can increase the radiosensitization effect of IUdR

Comparison of transplantation of bone marrow stromal cells [BMSC] and stem cell mobilization by granulocyte colony stimulating factor after traumatic brain injury in rat

Recent clinical studies of treating traumatic brain injury [TBI] with autologous adult stem cells led us to compare effect of intravenous injection of bone marrow mesenchymal stem cells [BMSC] and bone marrow hematopoietic stem cell mobilization, induced by granulocyte colony stimulating factor [G-CSF], in rats with a cortical compact device. Forty adult male Wistar rats were injured with controlled cortical impact device and divided randomly into four groups. The treatment groups were injected with 2 x 10[6] intravenous bone marrow stromal stem cell [n = 10] and also with subcutaneous G-CSF [n = 10] and sham-operation group [n = 10] received PBS and [bromodeoxyuridine [Brdu]] alone, i.p. All injections were performed 1 day after injury into the tail veins of rats. All cells were labeled with Brdu before injection into the tail veins of rats. Functional neurological evaluation of animals was performed before and after injury using modified neurological severity scores [mNSS]. Animals were sacrificed 42 days after TBI and brain sections were stained by Brdu immunohistochemistry. Statistically, significant improvement in functional outcome was observed in treatment groups compared with control group [P<0.01]. mNSS showed no significant difference between the BMSC and G-CSF-treated groups during the study period [end of the trial]. Histological analyses showed that Brdu-labeled [MSC] were present in the lesion boundary zone at 42[nd] day in all injected animals. In our study, we found that administration of a bone marrow-stimulating factor [G-CSF] and BMSC in a TBI model provides functional benefits

Transplantation of olfactory mucosa improve functional recovery and axonal regeneration following sciatic nerve repair in rats

Olfactory ensheathing glia [OEG] has been shown to have a neuroprotective effect after being transplanted in rats with spinal cord injury. This study was conducted to determine the possible beneficial results of olfactory mucosa transplantation [OMT] which is a source of OEG on functional recovery and axonal regeneration after transection of the sciatic nerve. In this study, 36 adult female Sprague-Dawley rats were used. The sciatic nerve was transected in 24 rats and immediately repaired by sciatic-sciatic anastomosis, and randomly divided equally into two groups. The experimental group received the OMT at the transected site and the control group received the respiratory mucosa transplant. In another twelve rats as sham-operated animals, the sciatic nerve was exposed but no transection was made. DiI retrograde tracing was injected in the gastrocnemius muscle two months after surgery to allow visualization of the extent of axonal regeneration. Functional recovery was also assessed at 15, 30, 45 and 60 days after surgery using walking track analysis and sciatic function index [SFI] calculations. The total number of DiI labeled motorneurones in the ventral horn [L4-L6] and the SFI scores were significantly higher in the group of rats that received olfactory mucosa rather than respiratory mucosa. The outcome indicates that olfactory mucosa is a useful treatment to improve nerve regeneration in mammals with peripheral nerve injury

Cytogenetic damages from iododeoxyuridine-induced radiosensitivity with and without methoxyamine in human glioblastoma spheroids

lododeoxyuridine-induced Radiosensitivityi [IUdR] is a halogenated thymidine analogue recognized to be effective in vitro and in vivo radioserisitizer in human cancers. It is reported that Methoxyamine [MX] potentiates DNA damages in cancer cells with blocking the repair pathway of lUdR damages. But studies, entirely, are restricted on monolayer culture cells from human colon cancer cells. Spheroids are 3D form of cells that aggregate and grow together which resemble in vivo tumor models in several aspects and the results of such studies can be extended to tumor in vivo. The aim of the current study was to evaluate DNA damages from IUdR and gamma rays with and without Methoxyamine in human Glioblastoma spheroids. The DNA induced damages in U87MG cell line were compared using alkaline comet assay method. Experiments were performed with two different sizes of spheroids [100omicrom and 300microm]. Evaluation of the effects of IUdR with and without MX pretreatment on spheroids following ionizing radiation showed that MX increased the cell damages of lUdR with and without irradiation in both diameters spheroids. The damages were further increased in 100microm compared with 300microm diameter. Comparisons of tail moments in spheroids with 100 and 300microm diameter showed that cell damages in larger spheroids, 300microm, are lesser than smaller one, 100microm. This could be due to existence of G[0] cells and cells with longer cycle which lUdR was less incorporated into them. Thus, decrease in lUdR radiosensitization and base wxcision repair [BER], results in reduction of MX activities. Using agents for Inhibiting the activities of proteins which are responsible for carrying the cells to G[0] may be beneficial in solving such problems