An Update on the Role of mpMRI and 68Ga-PSMA PET Imaging in Primary and Recurrent Prostate Cancer.

The objective of this work was to review comparisons of the efficacy of 68Ga-PSMA-11 (prostate-specific membrane antigen) PET/CT and multiparametric magnetic resonance imaging (mpMRI) in the detection of prostate cancer among patients undergoing initial staging prior to radical prostatectomy or experiencing recurrent prostate cancer, based on histopathological data. A comprehensive search was conducted in PubMed and Web of Science, and relevant articles were analyzed with various parameters, including year of publication, study design, patient count, age, PSA (prostate-specific antigen) value, Gleason score, standardized uptake value (SUVmax), detection rate, treatment history, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and PI-RADS (prostate imaging reporting and data system) scores. Only studies directly comparing PSMA-PET and mpMRI were considered, while those examining combined accuracy or focusing on either modality alone were excluded. In total, 24 studies comprising 1717 patients were analyzed, with the most common indication for screening being staging, followed by relapse. The findings indicated that 68Ga-PSMA-PET/CT effectively diagnosed prostate cancer in patients with suspected or confirmed disease, and both methods exhibited comparable efficacy in identifying lesion-specific information. However, notable heterogeneity was observed, highlighting the necessity for standardization of imaging and histopathology systems to mitigate inter-study variability. Future research should prioritize evaluating the combined diagnostic performance of both modalities to enhance sensitivity and reduce unnecessary biopsies. Overall, the utilization of PSMA-PET and mpMRI in combination holds substantial potential for significantly advancing the diagnosis and management of prostate cancer.

Optimization of the Duration and Dose of Photobiomodulation Therapy (660 nm Laser) for Spinal Cord Injury in Rats.

Objective: Spinal cord injury (SCI) causes motor deficits, urinary incontinence, and neuropathic pain. This study was designed to optimize a photobiomodulation therapy (PBMT) protocol using a continuous wave (CW) 660 nm laser in rats with SCI. Specifically, the number of days of irradiation and the daily dose of PBMT were investigated. Methods: The study was performed in two steps. In the first step, a comparison between the effects of PBMT (45 sec) daily for 2 and 4 weeks on pain and movement [Basso, Beattie, and Brenham (BBB) score] was made. In the second step, a comparison between different durations of irradiation (27, 45, 90, and 117 sec) was performed. PBMT used a 100 mW laser delivered to 9 points on and around the lesion site. Oxidative stress, fibroblast invasion, and time to achieve spontaneous urination were also assessed. Results: The improvement in movement and pain stopped with discontinuation of radiation at week 2 and fibroblast invasion resumed. No improvement was seen in movement and pain in the group receiving PBMT for 27 sec compared with the groups receiving higher doses of laser radiation. Animals receiving 117 sec of photobiomodulation showed a higher BBB score even in the first 3 days. Conclusions: The number of days is an important factor for improving mobility; however, the daily dose of radiation is more important for pain relief.

The Application of ATR Kinase Inhibitor AZD6738 in Combination with Radiotherapy for the Treatment of Melanoma.

Background: Melanoma is categorized as one of the most malignant, severe, and lethal cancers of the skin. Regarding the lack of efficiency of conventional therapies for most patients, novel therapeutic strategies are strongly required. Objective: The current study aimed to assess the impact of AZD6738- an ATR kinase inhibitor- in combination with 6 MV X-ray on the human melanoma cell line (A375). Material and Methods: In this experimental study, cells were treated with different concentrations of AZD6738 for 24 and 48 h in the presence and absence of radiation (2 Gy, 4 Gy, and 6 Gy). The cell viability and cell proliferation assay were examined in both experimental and control groups by MTT and colony formation techniques, respectively. Results: The results indicated that by increasing the concentration of AZD6738, the cell viability was markedly diminished in all treatment groups. As expected, the cell viability of the cells treated with AZD6738 and radiation was significantly lower than the group treated with AZD6738 alone. Besides, the combinatory treatment significantly decreased cell proliferation in the melanoma cell line. The combination of AZD6738 with radiation resulted in a significant increase in cytotoxicity by a 50% increase in cell death when used at concentrations of 0.3 µM, 1 µM, 1.51 µM, and 1.61 µM, respectively. Conclusion: The combination of AZD6738 with radiation possesses a synergistic effect on the reduction of the cell viability and proliferation of melanoma cells. This present study provides insight into the impact of Ataxia Telangiectasia and Rad3-related kinase (ATR) inhibition on the potential role of this kinase in the suppression of melanoma cell proliferation.

Mechanistic aspects of photobiomodulation therapy in the nervous system.

Photobiomodulation therapy (PBMT) previously known as low-level laser therapy (LLLT) has been used for over 30 years, to treat neurological diseases. Low-powered lasers are commonly used for clinical applications, although recently LEDs have become popular. Due to the growing application of this type of laser in brain and neural-related diseases, this review focuses on the mechanisms of laser action. The most important points to consider include the photon absorption by intracellular structures; the effect on the oxidative state of cells; and the effect on the expression of proteins involved in oxidative stress, inflammation, pain, and neuronal growth.

The Use of ß-Elemene to Enhance Radio Sensitization of A375 Human Melanoma Cells.

OBJECTIVE: Melanoma is the most malignant and severe type of skin cancer. It is a tumor with a high risk of metastasis and resistant to conventional treatment methods (surgery, radiotherapy, and chemotherapy). ß-elemene is the most active constituent of Curcuma wenyujin which is a non-cytotoxic antitumor drug, proved to be effective in different types of cancers. The study aimed to investigate the therapeutic effects of ß-elemene in combination with radiotherapy on A375 human melanoma. MATERIALS AND METHODS: In this experimental study, human melanoma cells were grown in the monolayer culture model. The procedure of the treatment was performed by the addition of different concentrations of ß-elemene to the cells. Then, the cells were exposed to 2 and 4 Gy X-ray in different incubation times (24, 48, and 72 hours). The MTT assay was used for the determination of the cell viability. To study the rate of apoptosis response to treatments, the Annexin V/PI assay was carried out. RESULTS: The results of the MTT assay showed ß-elemene reduced the cell proliferation in dose- and time-dependent manners in cells exposed to radiation. Flow cytometry analysis indicated that ß-elemene was effective in the induction of apoptosis. Furthermore, the combination treatment with radiation remarkably decreased the cells proliferation ability and also enhanced apoptosis. For example, cell viability in a group exposed to 40 µg/ml of ß-elemene was 80%, but combination treatment with 6 MV X beam at a dose of 2 Gy reduced the viability to 61%. CONCLUSION: Our results showed that ß-elemene reduced the proliferation of human melanoma cancer cell through apoptosis. Also, the results demonstrated that the radio sensitivity of A375 cell line was significantly enhanced by ß-elemene. The findings of this study indicated the efficiency of ß-elemene in treating melanoma cells and the necessity for further research in this field.

The Combination of Metformin and Disulfiram-Cu for Effective Radiosensitization on Glioblastoma Cells.

OBJECTIVE: Glioblastoma (GBM) is one of the devastating types of primary brain tumors with a negligible response to standard therapy. Repurposing drugs, such as disulfiram (DSF) and metformin (Met) have shown antitumor properties in different cell lines, including GBM. In the present study, we focused on the combinatory effect of Met and DSF-Cu on the induction of apoptosis in U87-MG cells exposed to 6-MV X-ray beams. MATERIALS AND METHODS: In this experimental study, the MTT assay was performed to evaluate the cytotoxicity of each drug, along with the combinatory use of both. After irradiation, the apoptotic cells were assessed using the flow cytometry, western blot, and real-time polymerase chain reaction (RT-PCR) to analyze the expression of some cell death markers such as BAX and BCL-2. RESULTS: The synergistic application of both Met and DSF had cytotoxic impacts on the U87-MG cell line and made them sensitized to irradiation. The combinatory usage of both drugs significantly decreased the cells growth, induced apoptosis, and caused the upregulation of BAX, P53, CASPASE-3, and it also markedly downregulated the expression of the anti-apoptotic protein BCL-2 at the gene and protein levels. CONCLUSION: It seems that the synergistic application of both Met and DSF with the support of irradiation can remarkably restrict the growth of the U87-MG cell line. This may trigger apoptosis via the stimulation of the intrinsic pathway. The combinatory use of Met and DSF in the presence of irradiation could be applied for patients afflicted with GBM.

Investigation of combined photodynamic and radiotherapy effects of gallium phthalocyanine chloride on MCF-7 breast cancer cells.

In this study, we evaluated the effect of gallium phthalocyanine chloride (GaPcCl) as a radio- and photosensitizer on MCF-7 breast cancer cell line. We incubated cells with GaPcCl in different concentrations (from 3.125 to 100 µg/ml). Then cells in separate groups were exposed to different light doses (1.8 and 2.8 J/cm2) at wavelength of 660 nm and 2-Gy X-ray ionizing radiation, alone and in combination. Finally, cell survival and apoptosis were determined by MTT assay and flow cytometry, respectively. The results showed that the deactivated GaPcCl at concentration of 100 µg/ml reduces the cell viability up to 15%. While, photoactivated GaPcCl (100 µg/ml) at light dose of 2.8 J/cm2 significantly decreases cell viability up to 55.3%. Although MTT assay demonstrated that GaPcCl is not act as a radiosensitizer, flow cytometry showed significant increase in cell apoptosis when GaPcCl was exposed to 2 Gy X-ray. Using of GaPcCl-PDT (photodynamic therapy) integration with X-ray substantially increased cell death in comparison to the absence of X-ray. Furthermore, flow cytometry displayed a significant increase in apoptosis cells (especially late apoptosis) in this combination therapy. Our result proved that GaPcCl is an effective photosensitizer in MCF-7 human breast cancer cell line. The combination of GaPcCl-PDT and radiotherapy can be an efficient treatment against cancer. This approach needs further investigations on animal models for human purposes.Graphic abstract.

Investigating the effect of near infrared photo thermal therapy folic acid conjugated gold nano shell on melanoma cancer cell line A375.

Nowadays, there is growing interest regarding the use of metal Nanoshells as targeted agents of Nano-photo thermal cancer therapy. This study was aimed at synthesis the folic acid (FA)-conjugated with silica @gold core-shell nanoparticles (FA-SiO2@AuNPs) for improving the treatment of melanoma cancer cells. The characterization data showed that the FA-SiO2@AuNPs is spherical in shape and its size is ∼73.7 nm. The intracellular uptake of FA-SiO2@AuNPs into melanoma cells (A375) was measured through the inductively coupled plasma, (∼47.7%). The cytotoxicity of nanoparticles was investigated on A375 and HDF (Human dermal fibroblast) cell lines. Cytotoxicity results indicated that there is no significant cytotoxicity in HDF cell lines treated with nanoparticles. MTT and flow cytometry results showed that the viability of A375 cells treated by SiO2@Au and FA-SiO2@AuNPs was decreased significantly to about 31% and 16% respectively. The higher toxicity of cancer cells was obtained for the cells exposed to 808 nm near-infrared (NIR) laser after incubation with FA-SiO2@AuNPs rather than the non-targeted SiO2@AuNPs. Furthermore, about 64% more cell death was observed for A-375 cells using both photothermal therapy and treatment with FA-SiO2@AuNPs compared to photothermal therapy. Additionally, the majority of the cell deaths were related to the apoptosis process, not necrosis. It can be concluded that FA-SiO2@AuNPs was an effective targeting agent for photothermal therapy in the treatment of melanoma.

NIR triggered glycosylated gold nanoshell as a photothermal agent on melanoma cancer cells.

Nowadays, gold nanoshells are used in targeted nano photothermal cancer therapy. This study surveyed the application of gold nanoshell (GNs) to thermal ablative therapy for melanoma cancer cells and it takes advantage of the near infrared absorption of gold nanoshells. The synthesis and characterization of glycosylated gold nanoshells (GGNs) were done. The cytotoxicity and photothermal effects of GNs on melanoma cells were evaluated using MTT assay and flow cytometry. The characterization data showed that GGNs are spherical, with a hydrodynamic size of 46.7 nm. Results suggest that the cellular uptake of GGNs was about 78%. Viability assays showed no significant toxicity at low concentrations of GNs. The higher heating rate and toxicity of cancer cells were obtained for the cells exposed to 808 nm NIR laser after incubation with GGNs rather than the GNs. The viability of these cells has dramatically decreased by 29%. Furthermore, 61% more cell lethality was achieved for A375 cells using combined photothermal therapy and treatment with GGNs in comparison to NIR radiation alone. In conclusion, our findings suggest that the synthesized gold/silica core-shell nanoparticles conjugated with glucosamine have high potentials to be considered as an efficient metal-nanoshell in the process of targeted cancer photothermal therapy.

Cytogenetic damage from hyperthermia,6 MV X-rays, and topotecan in glioblastoma spheroids, simultaneously, and separately.

PURPOSE: Glioblastoma multiform (GBM) is one of the most common brain tumors. Surgery, radiation therapy, hyperthermia, and chemotherapy are the most common treatments for brain tumors such as GBM. This study investigated the cytogenetic damage caused by hyperthermia, radiation (6 MV-X-rays), and topotecan in glioma spheroids, simultaneously and separately. MATERIALS AND METHODS: Human glioblastoma cell line was cultured to form spheroids 350 µm in diameter that were arranged in eight groups and coded as follows: control, T: topotecan, H: hyperthermia, T + H: topotecan + hypertermia, X 1-10: X-ray with 1-10 fraction irradiation, H + X (1-10): hypertermia + X-ray with 1-10 fraction irradiation, T + X (1-10): topotecan + X-ray with 1-10 fraction irradiation, and H + T + X (1-10): hypertermia + topotecan + X-ray with 1-10 fraction irradiation. DNA damage was then evaluated using clonogenic assay. RESULTS: The effect of combined treatment with X + H + T was greater than the sum of the effects in other groups. In H + T + X group, failure to form colonies was observed in the seventh session. CONCLUSION: Use of X + H + T combination therapy significantly increased cell death and possibly improved the treatment. This suggests that the synergistic effect of different therapeutic methods increased cell death in glioblastoma tumor cells and reduced the necessary dose of radiation in the treatment of tumor in radiation therapy.

Cabazitaxel inhibits proliferation and potentiates the radiation response of U87MG glioblastoma cells.

Cabazitaxel is a second-generation semisynthetic taxane. The recognized anti-neoplastic effect of Cabazitaxel is cell cycle perturbation by inducing arrest at G2/M. Since glioblastoma tumors have a relatively high expression of P-gp, it is encouraging to find a treatment that is effective against these tumors. This study was conducted to examine the radiosensitizing potential of Cabazitaxel against U87MG cells. In order to evaluate the effect of Cabazitaxel, cells were treated with different concentrations of the drug at different time intervals and then cytotoxicity and cell cycle were assessed using MTT and flow cytometry assays, respectively. Annexin/PI and real-time polymerase chain reaction (PCR) assays were used to evaluate the extent of apoptosis. Cabazitaxel exerted a consistent G2/M arrest and resulted in a concentration- and time-dependent toxicity. Cabazitaxel enhanced the cytotoxicity response of U87MG cells to radiation. Apoptosis increased following Cabazitaxel-IR administration. At the same time, these results were further supported by apoptotic genes regulation. This study provides the first preclinical evidence supporting that Cabazitaxel can render U87MG cells more susceptible to the cytotoxicity of radiation and could potentially be administered in combination modalities as a promising cell cycle-specific radiosensitizer for the future steps of in vivo evaluation.

The combination of A-966492 and Topotecan for effective radiosensitization on glioblastoma spheroids.

Radiotherapy is one of the modalities in the treatment of glioblastoma patients, but glioma tumors are resistant to radiation and also chemotherapy drugs. Thus, researchers are investigating drugs which have radiosensitization capabilities in order to improve radiotherapy. PARP enzymes and topoisomerase I enzymes have a critical role in repairing DNA damage in tumor cells. Thus, inhibiting activity of these enzymes helps stop DNA damage repair and increase DSB lethal damages. In the current study, we investigated the combination of TPT as a topoisomerase I inhibitor, and A-966492 as a novel PARP inhibitor for further radiosensitization. U87MG cells (a human glioblastoma cell line) were cultured in Poly-Hema coated flasks to reach 300 µm-diameter spheroids. Treatments were accomplished by using non-toxic concentrations of A-966492 and Topotecan. The surviving fraction of treated cells was determined by clonogenic assay after treatment with drugs and 6 MV X-ray. The γ-H2AX expression was measured by an immunofluorescence staining method to examine the influence of A-966492, TPT and radiation on the induction of double stranded DNA breaks. Treatments using the A-966492 drug were conducted in concentration of 1 µM. Combining A-966492 and TPT with radiation yielded enhanced cell killing, as demonstrated by a sensitizer enhancement ratio at 50% survival (SER50) 1.39 and 1.16 respectively. Radio- and chemo-sensitization was further enhanced when A-966492 was combined with both X-ray and TPT, with SER50 of 1.53. Also γ-H2AX expression was higher in the group treated with a combination of drugs and radiation. A-966492 is an effective PARP inhibitor and has significant radio-sensitivity on U87MG spheroids. By accumulating cells in the S phase and by inhibiting the DNA damage repair, TPT enhanced radio-sensitivity. A-966492 combined with TPT as a topoisomerase I inhibitor had additive radio-sensitizing effects. As a result, applying PARP and topoisomerase I inhibitors can be a suitable strategy for improving radiotherapy in clinics.

Genotoxic Damage to Glioblastoma Cells Treated with 6 MV X-Radiation in The Presence or Absence of Methoxy Estradiol, IUDR or Topotecan.

OBJECTIVE: To explore the cumulative genotoxic damage to glioblastoma (GBM) cells, grown as multicellular spheroids, following exposure to 6 MV X-rays (2 Gy, 22 Gy) with or without, 2- methoxy estradiol (2ME2), iododeoxyuridine (IUDR) or topotecan (TPT), using the Picogreen assay. MATERIALS AND METHODS: The U87MG cells cultured as spheroids were treated with 6 MV X-ray using linear accelerator. Specimens were divided into five groups and irradiated using X-ray giving the dose of 2 Gy after sequentially incubated with one of the following three drug combinations: TPT, 2-ME2/TPT, IUDR/TPT or 2ME2/IUDR/ TPT. One specimen was used as the irradiated only sample (R). The last group was also irradiated with total dose of 22 Gy (each time 2 Gy) of 6 MV X-ray in 11 fractions and treated for three times. DNA damage was evaluated using the Picogreen method in the experimental study. RESULTS: R/TPT treated group had more DNA damage [double strand break (DSB)/single strand break (SSB)] compared with the untreated group (P<0.05). Moreover the R/ TPT group treated with 2ME2 followed by IUDR had maximum DNA damage in spheroid GBM indicating an augmented genotoxicity in the cells. The DNA damage was induced after seven fractionated irradiation and two sequential treatments with 2ME2/IUDR/TPT. To ensure accuracy of the slope of dose response curve the fractionated radiation was calculated as 7.36 Gy with respect to α/ß ratio based on biologically effective dose (BED) formulae. CONCLUSION: Cells treated with 2ME2/IUDR showed more sensitivity to radiation and accumulative DNA damage. DNA damage was significantly increased when GBM cells treated with TPT ceased at S phase due to the inhibition of topoisomerase enzyme and phosphorylation of Chk1 enzyme. These results suggest that R/TPT- treated cells increase sensitivity to 2ME2 and IUDR especially when they are used together. Therefore, due to an increase in the level of DNA damage (SSB vs. DSB) and impairment of DNA repair machinery, more cell death will occur. This in turn may improve the treatment of GBM.

DNA damage of glioblastoma multiform cells induced by Beta radiation of iodine-131 in the presence or absence of topotecan: a picogreen and colonogenic assay.

OBJECTIVE: Glioblastoma multiforme (GBM), one of the most common and aggressive malignant brain tumors, is highly resistant to radiotherapy. Numerous approaches have been pursued to find new radiosensitizers. We used a picogreen and colonogenic assay to appraise the DNA damage and cell death in a spheroid culture of GBM cells caused by iodine-131 (I-131) beta radiation in the presence of topotecan (TPT). MATERIALS AND METHODS: U87MG cells were cultured as spheroids with approximate diameters of 300 µm. Cells were treated with beta radiation of I-131 (at a dose of 2 Gy) and/ or TPT (1 µg/ml for 2 hours). The numbers of cells that survived were compared with untreated cells using a colonogenic assay. In addition, we evaluated possible DNA damages by the picogreen method. The relation between DNA damage and cell death was assessed in the experimental study of groups. RESULTS: The findings showed that survival fraction (SF) in the I-131+TPT group (39%) was considerably less than the I-131 group (58.92%; p<0.05). The number of single strand breaks (SSB) and double strand breaks (DSB), in the DNA of U87MG cells treated with beta radiation of I-131 and TPT (I-131+TPT) significantly increased compared to cells treated with only I-131 or TPT (p<0.05). The amount of SSB repair was more than DSB repair (p<0.05). The relationship between cell death and DNA damage was close (r≥0.6) and significant (p<0.05) in the irradiated and treated groups. Also the maximum rate of DNA repair occurred 24 hours after the treatments. A significant difference was not observed on other days of the restoration. CONCLUSION: The findings in the present study indicated that TPT can sensitize U87MG cells to radiation and increase DNA damages. Potentially, TPT can cause an increase in damage from DSB and SSB by its inhibitory effects on topoisomerase enzyme and the cell cycle. The increased complex damages following the use of a genotoxic agent and beta I-131 radiation, causes a significant increase the cell death because of the difficult repair process. By assessing the relationship between DNA damage and cell death, the picogreen method can be useful in predicting colonogenic assay. Consequently, it is suggested that co-treatment with I-131 beta radiation and TPT can improve GBM treatment.

Evaluation of The Combined Effects of Hyperthermia, Cobalt-60 Gamma Rays and IUdR on Cultured Glioblastoma Spheroid Cells and Dosimetry Using TLD-100.

OBJECTIVE: In radiation treatment, the irradiation which is effective enough to control the tumors far exceeds normal-tissues tolerance. Thus to avoid such unfavourable outcomes, some methods sensitizing the tumor cells to radiation are used. Iododeoxyuridine (IUdR) is a halogenated thymidine analogue that known to be effective as a radiosensitizer in human cancer therapy. Improving the potential efficacy of radiation therapy after combining to hyperthermia depends on the magnitude of the differential sensitization of the hyperthermic effects or on the differential cytotoxicity of the radiation effects on the tumor cells. In this study, we evaluated the combined effects of IUdR, hyperthermia and gamma rays of (60)Co on human glioblastoma spheroids culture. MATERIALS AND METHODS: In this experimental study,the cultured spheroids with 100µm diameter were treated by 1 µM IUdR, 43°C hyperthermia for an hour and 2 Gy gamma rays, respectively. The DNA damages induced in cells were compared using alkaline comet assay method, and dosimetry was then performed by TLD-100. Comet scores were calculated as mean ± standard error of mean (SEM) using one-way ANOVA. RESULTS: Comparison of DNA damages induced by IUdR and hyperthermia + gamma treatment showed 2.67- and 1.92-fold enhancement, respectively, as compared to the damages induced by radiation alone or radiation combined IUdR. Dosimetry results showed the accurate dose delivered to cells. CONCLUSION: Analysis of the comet tail moments of spheroids showed that the radiation treatments combined with hyperthermia and IUdR caused significant radiosensitization when compared to related results of irradiation alone or of irradiation with IUdR. These results suggest a potential clinical advantage of combining radiation with hyperthermia and indicate effectiveness of hyperthermia treatment in inducing cytotoxicity of tumor cells.

Relative Biological Effectiveness (RBE) of (131)I Radiation Relative to (60)Co Gamma Rays.

OBJECTIVE: To assess relative biological effectiveness (RBE) of (131)I radiation relative to (60)Co gamma rays in glioblastoma spheroid cells. MATERIALS AND METHODS: : In this experimental study, glioblastoma spheroid cells were exposed to (131)I radiation and (60)Co gamma rays. Radiation induced DNA damage was evaluated by alkaline comet assay. Samples of spheroid cells were treated by radiation from (131)I for four different periods of time to find the dose-response equation. Spheroid cells were also exposed by 200 cGy of (60)Co gamma rays as reference radiation to induce DNA damage as endpoint. RESULTS: Resulted RBE of (131)I radiation relative to (60)Co gamma rays in 100 µm giloblastoma spheroid cells was equal to 1.16. CONCLUSION: The finding of this study suggests that (131)I photons and electrons can be more effective than (60)Co gamma rays to produce DNA damage in glioblastoma spheroid cells.

DNA Damage Induced in Glioblastoma Cells by I-131: A Comparison between Experimental Data and Monte Carlo Simulation.

OBJECTIVE: The passage of ionizing radiation in living cells creates clusters of damaged nucleotides in DNA. In this study, DNA strand breaks induced by the beta particle of iodine-131 (I-131), have been determined experimentally and compared to Monte Carlo simulation results as a theoretical method of determining(131)I damage. MATERIALS AND METHODS: In this experimental study, in order to create single strand breaks (SSB) and double strand breaks (DSB) in the DNA, glioblastoma (GBM) cells were exposed to 10 mCi I-131, at a dose of 2 Gy. Damage of irradiated cells were evaluated quantitatively by the Fast Micromethod assay. The energy spectrum of electrons released in cells were obtained by the macroscopic Monte Carlo code (MCNP4c) and used as an input of the micro Monte Carlo code (MCDS). The percent of damage induced in cells was analyzed by Mann-Whitney test. RESULTS: A significant reduction (p<0.05) in fluorescence intensity in irradiated cells compared to control cells as determined by the Fast Micromethod assay represented induced SSB and DSB damages in the DNA of irradiated cells. Comparison of experimental and theoretical results showed that the difference between the percentages of SSB per Gy was about 7.4% and DSB was about 1% per Gy. CONCLUSION: The differences in experimental and theoretical results may be due to the algorithm of applied codes. Since the Fast Micromethod and other experimental techniques do not provide information about the amount of detailed and complex damages of DNA-like base damages, the applied Monte Carlo codes, due to their capability to predict the amount of detailed damages that occur in the DNA of irradiated cells, can be used in in vitro experiments and radiation protection areas.

Evaluation of the Combined Effect of 2ME2 and (60)Co on the Inducement of DNA Damage by IUdR in a Spheroid Model of the U87MG Glioblastoma Cancer Cell Line Using Alkaline Comet Assay.

OBJECTIVE: In this study, we investigated the combined effect of 2-Methoxyestradiol (2ME2) and (60)Co on the cytogenetic damage of iododeoxyuridine (IUdR) in the spheroid model of U87MG glioblastoma cancer cell lines by alkaline comet assay. MATERIALS AND METHODS: U87MG cells were cultured as spheroids with diameters of 350 µm. As control, the spheroids of one plate were not treated. Other cultures were pretreated with 2ME2 (250 µM) for one volume doubling time (1 VDT). After this time, the subsequent treatments were performed according to the following groups: Vehicle (this sample was not treated in the 2(nd) VDT) Treated with 2ME2 (250 µM) for 1 VDT Treated simultaneously with 2ME2 (250 µM) and IUdR (1 µM) for 1 VDT Treated with 2ME2 (250 µM) for 1 VDT then irradiated with (60)Co (2 Gy) Treated simultaneously with 2ME2 (250 µM) and IUdR (1 µM) for 1 VDT then irradiated with (60)Co (2 Gy) Then the DNA damage was evaluated using the alkaline comet assay method. RESULTS: The results showed that 2ME2 in combination with gamma irradiation of (60)Co 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. CONCLUSION: By inhibiting the HIF-1α 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 (60)Co can increase the radiosensitization effect of IUdR.

The role of heat shock protein 70 in the thermoresistance of prostate cancer cell line spheroids.

Heat shock protein 70 (Hsp70), a protein induced in cells exposed to sublethal heat shock, is present in all living cells and has been highly conserved during evolution. The aim of the current study was to determine the role of heat shock proteins in the resistance of prostate carcinoma cell line spheroids to hyperthermia. In vitro, the expression of Hsp70 by the DU 145 cell line, when cultured as monolayer or multicellular spheroids, was studied using Western blotting and enzyme-linked immunosorbent assay methods. The level of Hsp70 in spheroid cultures for up to 26 days at 37 degrees C remained similar to monolayer cultures. However, in samples treated with hyperthermia at 43 degrees C for 120 min, the spheroid cultures expressed a higher level of Hsp70 as compared to monolayer culture. Under similar conditions of heat treatment, the spheroids showed more heat resistance than monolayer cultures as judged by the number of colonies that they formed in suspension cultures. The results suggest that cells cultured in multicellular spheroids showed more heat resistance as compared to monolayer cultures by producing higher levels of Hsp70.