Low-Dose Hypersensitivity and Bystander Effect are Not Mutually Exclusive in A549 Lung Carcinoma Cells after Irradiation with Charged Particles

The purpose of this study was to measure survival fraction of A549 lung carcinoma cells irradiated with charged particles of various LET and to determine mechanisms responsible for enhanced cell killing in the low-dose region. A549 cells were irradiated with a broadbeam of either 10 and 25 keV/μm protons or 100 keV/μm alpha particles and then processed for clonogenic assays and phospho-histone H3 staining. The survival fraction of unirradiated A549 cells co-cultured with irradiated cells was also evaluated. A549 cells were shown to exhibit low-dose hypersensitivity (HRS) for both protons and alpha particles. The dose threshold at which HRS occurs decreased with increasing linear energy transfer (LET), whereas αs, the initial survival curve slope, increased with increasing LET. In addition, the enhanced cell killing observed after irradiation with alpha particles was partly attributed to the bystander effect, due to the low proportion of hit cells at very low doses. Co-culture experiments suggest a gap junction-mediated bystander signal. Our results indicate that HRS is likely to be dependent on LET, and that a bystander effect and low-dose hypersensitivity may co-exist within a given cell line

Oncological patients' reactions to COVID-19 pandemic: A single institution prospective study.

peer reviewedBACKGROUND: The spread of the COVID-19 pandemic has led to a rapid reorganization in all human and hospital activities, with impact on cancer patients. AIM: An analysis of cancer patients fears, and awareness of COVID-19 has been done in this study. METHODS AND RESULTS: We analyzed cancer patients' reactions to the pandemic and their perception of oncological care reorganization, through a 12-item survey, proposed at the peak of pandemic and 3 months later. Overall, 237 patients were included in the study. During the peak of pandemic 34.6% of patients were more worried about COVID-19 than cancer versus 26.4% in the post-acute phase (p = .013). Although 49.8% of patients in the acute phase and 42.3% in the post-acute phase considered their risk of death if infected ≥50%, and more than 70% of patients thought to be at higher risk of complications, the majority of them did not consider the possibility to stop or delay their treatment. Patients were more interested in following news about COVID-19 than cancer and they complied with all preventive measures in more than 90% of the cases. CONCLUSIONS: Although cancer patients worried about COVID-19 and evaluated the risk of complication or death due to COVID-19 as extremely high, they were still asking for the best oncological treatment

Comparison of the clonogenic survival of A549 non-small cell lung adenocarcinoma cells after irradiation with low-dose-rate beta particles and high-dose-rate X-rays

Purpose: Lung cancer is the leading cause of cancer-related death. Among the new modalities to treat cancer, internal radiotherapy seems to be very promising. However, the achievable dose-rate is two orders of magnitude lower than the one used in conventional external radiotherapy, and data has to be collected to evaluate the cell response to highlight the potential effectiveness of low-dose-rate beta particles irradiation. This work investigates the phosphorus beta irradiation ( P) dose response on the clonogenicity of human A549 non-small cell lung adenocarcinoma cells and compares it to high-dose-rate X-irradiations results. Materials and methods: Cell survival was evaluated by a colony forming assay eight days after low-dose-rate P beta irradiations (0.8 Gy/h) and high-dose-rate X-ray irradiations (0.855 Gy/min). Results: Survival curves were obtained for both types of irradiations, and showed hyper-radiosensitivity at very low doses. Radiosensitivity parameters were obtained by using the linear-quadratic and induced-repair models. Conclusions: Comparison with high-dose-rate X-rays shows a similar surviving fraction, confirming the effectiveness of beta particles for tumor sterilization. © 2012 Informa UK, Ltd

Development of an in vitro irradiation station for broad beam radiobiological experiment: study of A549 non-small cell lung cancer cell response after irradiation with charged particles of different LET

Lung cancer is the leading cause of cancer related death. Currently, the average 5-year survival rate is only about 15 % and new modalities are under investigation to increase the patient survival as well as to improve the patient quality of life. Among the new modalities developed for the treatment of lung cancer, we find hadron-therapy and radio-immunotherapy both using charged particles. However, the studies performed about the potential benefit of such treatments emphasize that more data and fundamental works are needed to better understand the cellular response. In this work, the results obtained after the irradiation of A549 lung cancer cells with different types of charged particles (beta particles, protons, alpha particles and carbon ions) were compared to the standard X-ray irradiation. On one hand, the beta particles irradiations were performed with a liquid source at a low-dose-rate as found in actual radio-immunotherapy. On the other hand, a broad beam in vitro irradiation station was developed to perform heavy charged particles radiobiological experiment. For that purpose, the incident beam must be mono-energetic, uniform and stable. Although this can be obtained with the 2 MV Tandem accelerator of the LARN laboratory, one needs a system to check these requirements before performing the irradiation. The setup developed in this work allows visualising the beam to adjust the accelerator parameters in order to obtain a uniform beam. This system enables us to check the dose-rate and uniformity of the irradiated area before to proceed to the irradiation. Moreover, an online monitoring system has been developed to assess the dose-rate during the irradiation. The entire irradiation system has been validated by establishing the surviving fraction curves of A549 lung cancer cells after irradiation with protons, alpha particles and carbons ions. The results obtained have shown an increased efficiency of heavy charged particles in comparison to X-rays. The experiments carried out on A549 lung cancer cells with 10 keV/µm proton broad beam and with low-dose-rate beta particles have highlighted a hypersensitive response at low doses. This result is very interesting for the new modalities under development. Indeed, unlike cancer cells, normal cells have efficient repair mechanism and take the required time to repair. Hence, work with a lower dose-rate and/or dose, may lead to lower complication and a better patient’s quality of life with a same local control of the tumour.Le cancer du poumon est le plus meurtrier avec une survie moyenne à 5 ans de seulement 15%. De nouvelles modalités de traitement sont étudiées afin d’améliorer l’efficacité des traitements en terme de survie mais aussi de qualité de vie des patients. Parmi ces modalités, on retrouve l’hadron-thérapie et la radio-immunothérapie qui utilisent toutes deux des particules chargées. Cependant, les études réalisées jusqu’ici soulignent le manque de données expérimentales permettant de mieux comprendre la réponse cellulaire. Dans ce travail, les résultats obtenus après irradiation de cellules cancéreuses pulmonaires (type A549) avec différents types de particules chargées (particules béta, protons, particules alpha, ions carbone) ont été comparés avec ceux obtenus après irradiation par des rayons X standards. Les irradiations avec particules béta ont été réalisées avec une source liquide à faible débit de dose comme c’est le cas pour la radio-immunothérapie. En parallèle, une station d’irradiation in vitro à large faisceau a été développée afin de réaliser les irradiations avec des particules chargées lourdes. Les irradiations nécessitent un faisceau mono-énergétique, uniforme et stable. Ce type de faisceau peut être obtenu avec l’accélérateur Tandem du LARN mais nous avons besoin d’un système permettant de vérifier tous ces paramètres avant de réaliser une irradiation. Le système ainsi développé nous permet de visualiser le faisceau pour ajuster les paramètres de l’accélérateur afin d’obtenir un faisceau uniforme. Le dispositif permet également d’ajuster le débit de dose avant de débuter l’irradiation et de le contrôler tout au long de l’expérience. Ce système a été validé par la mesure de courbes de survie de cellules A549 après irradiation de protons, de particules alpha et d’ions carbone. Les résultats obtenus montrent une efficacité accrue des particules chargées lourdes en comparaison avec les rayons X. Les expériences réalisées sur les cellules cancéreuses pulmonaires (type A549) avec des protons de 10 keV/µm et des particules béta à faible débit de dose ont mis en évidence une réponse hypersensible aux faibles doses. Du point de vue des cellules saines avoisinant le volume tumoral à traiter, cette hypersensibilité aux faibles doses est très intéressante. En effet, les cellules normales possèdent des mécanismes de réparation efficaces et prennent le temps de se réparer lorsqu’un dommage leur a été occasionné. Par conséquent, utiliser de faibles débits de dose et/ou de faibles doses peut donner lieu à de moindres complications et ainsi obtenir une meilleure qualité de vie pour les patients tout en gardant un même contrôle local de la tumeur.(DOCSC01) -- FUNDP, 201

Taking Advantage of the Senescence-Promoting Effect of Olaparib after X-ray and Proton Irradiation Using the Senolytic Drug, ABT-263

Radiotherapy (RT) is a key component of cancer treatment. Although improvements have been made over the years, radioresistance remains a challenge. For this reason, a better understanding of cell fates in response to RT could improve therapeutic options to enhance cell death and reduce adverse effects. Here, we showed that combining RT (photons and protons) to noncytotoxic concentration of PARP inhibitor, Olaparib, induced a cell line-dependent senescence-like phenotype. The senescent cells were characterized by morphological changes, an increase in p21 mRNA expression as well as an increase in senescence-associated β-galactosidase activity. We demonstrated that these senescent cells could be specifically targeted by Navitoclax (ABT-263), a Bcl-2 family inhibitor. This senolytic drug led to significant cell death when combined with RT and Olaparib, while limited cytotoxicity was observed when used alone. These results demonstrate that a combination of RT with PARP inhibition and senolytics could be a promising therapeutic approach for cancer patients

Comparison of nanofluidic and ultra-high performance liquid chromatography-tandem mass spectrometry for high sensitive pharmacokinetic studies of estrogens starting from whole blood microsampling

Pharmacokinetic (PK) studies on small animals are challenging as only small volumes of samples are available, in which the analyte is present at low concentration in a complex matrix. In this context, the use of miniaturized analytical techniques may provide undeniable advantages in terms of sensitivity, sample and solvent consumption compared to the reference UHPLC-MS/MS methods In this study, we present the development of a nanofluidic-LC-MS/MS method to analyze two model analytes of therapeutic interest, namely estradiol (E2) and estetrol (E4) after microsampling with volumetric absorptive microsampling (VAMS) devices, an innovative sampling technique to collect small volumes of whole blood. The nanofluidic LC-MS/MS method was developed using an experimental design to find the optimal conditions to analyze both E2 and E4 with the highest sensitivity. Subsequently, the optimized method was validated according to ICH guidelines and compared to a previously developed UHPLC-MS/MS method. A limit of quantitation of 50. pg/ml was reached with the LC-chip method, which is 50 times better than UHPLC-MS/MS. Both methods were then critically evaluated from the analytical and operational points of view. Finally, the quantitation of estrogens after whole blood microsampling was compared with the results obtained with the corresponding plasma samples. © 2017 Elsevier B.V