Radiobiological studies on the 62 MeV therapeutic proton beam at lns catania: I. survival of HTB140 melanoma cells

The aim of this study was to determine the initial inactivation of cells induced by high-energy proton beam designed for the treatment of eye melanoma. Exponentially growing HTB140 cells were exposed to an unmodulated 62 MeV proton beam delivered over the single dose range from 8 Gy to 24 Gy. Position of samples was in the zone of the Bragg peak, having high LET values. Surviving fractions were evaluated at 6, 24 and 48 h post-irradiation. The survival curves exhibited a well-known shoulder, decreasing for doses higher than 8 Gy. Therefore, a significant dose dependent early cell inactivation after single delivery of 16 Gy to 24 Gy to the cell monolayer was observed. With the increase of the post-irradiation incubation time, a better killing effect, as the consequence of clonogenic survival, was detected.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Radiobiological studies on the 62 MeV therapeutic proton beam at lns catania: II. facs analyses of HTB140 melanoma cells

The objective of this study was to determine whether apoptosis and cell cycle redistribution were influenced by high-LET irradiation. Exponentially growing HTB140 cells were exposed to an unmodulated 62 MeV proton beam, within the Bragg peak, delivered over the single dose range from 8 Gy to 24 Gy. At 6 h post-irradiation, there was a low level of early apoptosis. At 48 h irradiated cells were more damaged, showing the increase in number of apoptotic nuclei. The dose dependent cell cycle phase distribution was detected at 48 h post-irradiation. The cell population exhibited phase redistribution toward G2/M phase.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Response of Human HTB140 Melanoma Cells to Conventional Radiation and Hadrons

Conventional radiotherapy with X-and gamma-rays is one of the common and effective treatments of cancer. High energy hadrons, i.e., charged particles like protons and (12)C ions, due to their specific physics and radiobiological advantages are increasingly used. In this study, effectiveness of different radiation types is evaluated on the radio-resistant human HTB140 melanoma cells. The cells were irradiated with gamma-rays, the 62 MeV protons at the Bragg peak and in the middle of the spread-out Bragg peak (SOBP), as well as with the 62 MeV/u (12)C ions. The doses ranged from 2 to 24 Gy. Cell survival and proliferation were assessed 7 days after irradiation, whereas apoptosis was evaluated after 48 h. The acquired results confirmed the high radio-resistance of cells, showing better effectiveness of protons than gamma-rays. The best efficiency was obtained with (12)C ions due to higher linear energy transfer. All analyzed radiation qualities reduced cell proliferation. The highest proliferation was detected for (12)C ions because of their large killing capacity followed by small induction of reparable lesions. This enabled unharmed cells to preserve proliferative activity. Irradiations with protons and (12)C ions revealed similar moderate pro-apoptotic ability that is in agreement with the level of cellular radio-resistance

Response of Human HTB140 Melanoma Cells to Conventional Radiation and Hadrons

Conventional radiotherapy with X-and gamma-rays is one of the common and effective treatments of cancer. High energy hadrons, i.e., charged particles like protons and (12)C ions, due to their specific physics and radiobiological advantages are increasingly used. In this study, effectiveness of different radiation types is evaluated on the radio-resistant human HTB140 melanoma cells. The cells were irradiated with gamma-rays, the 62 MeV protons at the Bragg peak and in the middle of the spread-out Bragg peak (SOBP), as well as with the 62 MeV/u (12)C ions. The doses ranged from 2 to 24 Gy. Cell survival and proliferation were assessed 7 days after irradiation, whereas apoptosis was evaluated after 48 h. The acquired results confirmed the high radio-resistance of cells, showing better effectiveness of protons than gamma-rays. The best efficiency was obtained with (12)C ions due to higher linear energy transfer. All analyzed radiation qualities reduced cell proliferation. The highest proliferation was detected for (12)C ions because of their large killing capacity followed by small induction of reparable lesions. This enabled unharmed cells to preserve proliferative activity. Irradiations with protons and (12)C ions revealed similar moderate pro-apoptotic ability that is in agreement with the level of cellular radio-resistance

Geant4 simulation model of electromagnetic processes in oriented crystals for the accelerator physics

Electromagnetic processes of charged particles interaction with oriented crystals provide a wide variety of innovative applications such as beam steering, crystal-based extraction/collimation of leptons and hadrons in an accelerator, a fixed-target experiment on magnetic and electric dipole moment measurement, X-ray and gamma radiation source for radiotherapy and nuclear physics and a positron source for lepton and muon colliders, a compact crystalline calorimeter as well as plasma acceleration in the crystal media. One of the main challenges is to develop an up-to-date, universal and fast simulation tool to simulate these applications. We present a new simulation model of electromagnetic processes in oriented crystals implemented into Geant4, which is a toolkit for the simulation of the passage of particles through matter. We validate the model with the experimental data as well as discuss the advantages and perspectives of this model for the applications of oriented crystals mentioned above.Comment: 18 pages, 9 figure

Carbon Ions Induce DNA Double Strand Breaks and Apoptosis in Htb140 Melanoma Cells

This study was conducted in order to evaluate the ability of carbon ions to induce DNA double-strand breaks and apoptosis in the radio-resistant human HTB140 melanoma cells. The cells were irradiated with C-12 ions having the linear energy transfer of 258 keV/mu m. Irradiations were performed in the dose range from 2 to 16 Gy. Induction of DNA double-strand breaks was evaluated 2 hour after irradiation through expression of gamma H2AX protein. Increased level of gamma H2AX detected in irradiated samples was especially high after irradiation with 12 and 16 Gy. Dose dependent increase of apoptosis was detected 48 hour after irradiation by flow-cytometry, with the maximum value of 20.4% after irradiation with 16 Gy, and the apoptotic index of 9.3. Pro-apoptotic effects of carbon ion beams were confirmed by changes of key molecules of the mitochondrial apoptotic pathway, p53 protein expression, Bax/Bcl-2 ratio and caspase-3 activation

Carbon ion beam as inducer of melanoma cell apoptosis

In vitro effect of carbon ions on apoptosis was studied. The human melanoma HTB140 cells were irradiated with the 62 MeV/u 12C ion beam. Percentage of apoptotic cells was evaluated by flow-cytometry and the corresponding apoptotic indexes were calculated. The expression of apoptosis-associated proteins, p53, Bax and Bcl-2 was estimated by Western blot analyses. A dose dependent increase of apoptosis was revealed, with the maximum value of 17 % after irradiation with 16 Gy, and the apoptotic index of 7.7. Pro-apoptotic effects of carbon ion beams were confirmed by the detected changes of key regulators of the mitochondrial apoptotic pathway, the p53 protein expression and the Bax/Bcl-2 ratio

A Monte Carlo study for the calculation of the average linear energy transfer (LET) distributions for a clinical proton beam line and a radiobiological carbon ion beam line

Fluence, depth absorbed dose and linear energy transfer (LET) distributions of proton and carbon ion beams have been investigated using the Monte Carlo code Geant4 (GEometry ANd Tracking). An open source application was developed with the aim to simulate two typical transport beam lines, one used for ocular therapy and cell irradiations with protons and the other for cell irradiations with carbon ions. This tool allows evaluation of the primary and total dose averaged LET and predict their spatial distribution in voxelized or sliced geometries. In order to reproduce the LET distributions in a realistic way, and also the secondary particles contributions due to nuclear interactions were considered in the computations. Pristine and spread-out Bragg peaks were taken into account both for proton and carbon ion beams, with the maximum energy of 62 MeV/n. Depth dose distributions were compared with experimental data, showing good agreement. Primary and total LET distributions were analysed in order to study the influence of contributions of secondary particles in regions at different depths. A non-negligible influence of high-LET components was found in the entrance channel for proton beams, determining the total dose averaged LET by the factor 3 higher than the primary one. A completely different situation was obtained for carbon ions. In this case, secondary particles mainly contributed in the tail that is after the peak. The results showed how the weight of light and heavy secondary ions can considerably influence the computation of LET depth distributions. This has an important role in the interpretation of results coming from radiobiological experiments and, therefore, in hadron treatment planning procedures

Carbon ions of different linear energy transfer (LET) values induce apoptosis and G2 cell cycle arrest in radio-resistant melanoma cells

Background and objectives: The main goal when treating malignancies with radiation is to deprive tumour cells of their reproductive potential. One approach is to induce tumour cell apoptosis. This study was conducted to evaluate the ability of carbon ions (C-12) to induce apoptosis and cell cycle arrest in human HTB140 melanoma cells. Methods: In this in vitro study, human melanoma HTB140 cells were irradiated with the 62 MeV/n carbon (C-12) ion beam, having two different linear energy transfer (LET) values: 197 and 382 keV/mu m. The dose range was 2 to 16 Gy. Cell viability was estimated by the sulforhodamine B assay seven days after irradiation. The cell cycle and apoptosis were evaluated 48 h after irradiation using flow cytometry. At the same time point, protein and gene expression of apoptotic regulators were estimated using the Western blot and q-PCR methods, respectively. Results: Cell viability experiments indicated strong anti-tumour effects of C-12 ions. The analysis of cell cycle showed that C-12 ions blocked HTB140 cells in G2 phase and induced the dose dependent increase of apoptosis. The maximum value of 21.8 per cent was attained after irradiation with LET of 197 keV/mu m at the dose level of 16 Gy. Pro-apoptotic effects of C-12 ions were confirmed by changes of key apoptotic molecules: the p53, Bax, Bcl-2, poly ADP ribose polymerase (PARP) as well as nuclear factor kappa B (NF kappa B). At the level of protein expression, the results indicated significant increases of p53, NF kappa B and Bax/Bcl-2 ratio and PARP cleavage. The Bax/Bcl-2 mRNA ratio was also increased, while no change was detected in the level of NF kappa B mRNA. Interpretation and conclusions: The present results indicated that anti-tumour effects of C-12 ions in human melanoma HTB140 cells were accomplished through induction of the mitochondrial apoptotic pathway as well as G2 arrest

Radiobiological Outcomes, Microdosimetric Evaluations and Monte Carlo Predictions in Eye Proton Therapy

CATANA (Centro di AdroTerapia ed Applicazioni Nucleari Avanzate) was the first Italian protontherapy facility dedicated to the treatment of ocular neoplastic pathologies. It is in operation at the LNS Laboratories of the Italian Institute for Nuclear Physics (INFN-LNS) and to date, 500 patients have been successfully treated. Even though proton therapy has demonstrated success in clinical settings, there is still a need for more accurate models because they are crucial for the estimation of clinically relevant RBE values. Since RBE can vary depending on several physical and biological parameters, there is a clear need for more experimental data to generate predictions. Establishing a database of cell survival experiments is therefore useful to accurately predict the effects of irradiations on both cancerous and normal tissue. The main aim of this work was to compare RBE values obtained from in-vitro experimental data with predictions made by the LEM II (Local Effect Model), Monte Carlo approaches, and semi-empirical models based on LET experimental measurements. For this purpose, the 92.1 uveal melanoma and ARPE-19 cells derived from normal retinal pigmented epithelium were selected and irradiated in the middle of clinical SOBP of the CATANA proton therapy facility. The remarkable results show the potentiality of using microdosimetric spectrum, Monte Carlo simulations and LEM model to predict not only the RBE but also the survival curves