Introduction – Treatment for breast cancer is associated with a risk of chronic shoulder and upper limb morbidity in up to 30% of patients. There is currently no consensus for the possible reason for this often repeated finding in the literature. Previous research has suggested that development of fibrotic tissue in response to cancer treatments such as surgery and radiotherapy could be an underlying cause of musculoskeletal dysfunction and pain. This study investigated if any genetic variants in several key fibrosis-modulating genes could be shown to be associated with risk of upper limb musculoskeletal dysfunction and pain in breast cancer survivors. Participants and Methods – A cross sectional study design was employed, using a candidate gene approach. A total of 326 South African breast cancer survivors were recruited from a tertiary hospital in the Western Cape (343 total, minus 17 samples with insufficient data collected). Each participant was scored for symptom severity using the shoulder pain and disability index (SPADI) questionnaire. Participants were then grouped for symptom severity using low, med or high SPADI scores. The low SPADI group served as controls (controls n=273, cases n=70). Participants were invited to donate a blood sample from which DNA was extracted. Each DNA sample was genotyped at seven polymorphic sites; three in TGF-ß, two in ATM, one in SOD2 and one in XRCC1, using PCR technologies and TaqMan allelic-discrimination probes. The resultant genotypes were analysed using multivariate analysis, including inferred haplotype analysis to search for association to shoulder pain and morbidity after treatment. A logistic regression analysis was also performed to investigate the association between SPADI score and age of participant. Results – When participant age was compared with symptom severity, it was found that younger participants were more likely to have moderate-to-severe symptoms than older participants. There was a significant difference in the minor allele frequencies between case and control groups for the rs4880 (C>T, SOD2) polymorphism. The T allele was present more in the case group than in controls, with minor allele frequencies of 0.67 vs 0.55 respectively. No other independent associations were noted for any of the remainder variants tested. When haplotypes were inferred for genes SOD2 and ATM, combinations between the rare alleles at rs4880 and rs1800058 (C>T, ATM) were associated (F=4.35, pT and ATM rs1800058 is recommended for further study, in addition to the rs4880 polymorphism in SOD2. These novel results are suggesting that there may be an association between fibrotic genes and the development of upper limb sequelae after treatment for breast cancer. A larger case-control study would be required to validate and explore these findings.

Les stratégies thérapeutiques anticancer sont nombreuses et variées. Elles visent à déclencher la mort des cellules tumorales mais les processus de mort cellulaire diffèrent en fonction du traitement, du type de cellule ciblé et des caractéristiques du patient. A côté des mécanismes classiques tels que l’apoptose et la nécrose, on retrouve également du cannibalisme cellulaire dans les biopsies de tumeurs des patients. Ce phénomène dont les mécanismes sont encore peu caractérisés, correspond à l’internalisation d’une cellule vivante par une cellule vivante. Il est fréquemment suivi par la dégradation de la cellule internalisée. Cette modalité de mort atypique est intéressante car nous avons montré qu’elle pouvait être modulée par des traitements anticancéreux et des études ont également démontré qu’elle pouvait servir de biomarqueur pronostique dans certains types de cancer. Ces travaux de thèse ont permis d'identifier des voies de signalisation cellulaire activées lors du déclenchement du cannibalisme cellulaire par les radiations ionisantes / Many types of anticancer therapies are available to kill tumor cells. The tumoral cell death modalities may be different upon the treatment, the cell type and inter-individual sensitivity. Besides the typical cell death processes apoptosis and necrosis, cellular cannibalism has also been reported in patients’ tumoral biopsies. This cellular process is defined as the engulfment of one live cell by another live cell followed by the degradation of the inner cell. The mechanisms beyond cellular cannibalism are still partially understoof but it appears to be of clinical relevance. Indeed, we have shown that these events could be modulated by anticancer treatments and there are evidences of their utility as a potent prognostic biomarker in some cancers. This thesis presents the in vitro experiments which led to the identification of the signaling pathways involved in cellular cannibalism induced by ionizing radiation.

La radiothérapie est l'une des principales modalités de traitement du cancer. Néanmoins, son utilisation est limitée du fait des dommages induits dans les tissus sains et de la radiorésistance de certains cas. En vue d’améliorer le ciblage tumoral et l'efficacité du traitement, des améliorations sont nécessaires. L'une des améliorations proposées est l'utilisation de nanoparticules composées d'éléments à nombre atomique élevé qui présentent la propriété d’amplifier l’effet des rayonnements ionisants. Les nanoparticules d'or constituent un des agents les plus prometteurs en raison de leur faible toxicité et de la possibilité d’y lier des molécules en surface. L’efficacité de petites nanoparticules d'or fonctionnalisées avec du DTDTPA (< 3 nm) a été prouvée. En revanche, peu de données existent quant au lien entre ces effets d’amplification et la dynamique d’internalisation et leur localisation dans les cellules.Ce travail a porté sur l’étude de la dynamique d'internalisation et d’excrétion de ces nanoparticules, ainsi que sur leur localisation dans différentes lignées cellulaires cancéreuses et dans les fibroblastes humains. Une tentative de corrélation entre les effets d’irradiation et ces données est proposée.Les résultats obtenus dans ce travail montrent que la dynamique d'absorption et d'excrétion, ainsi que les voies prédominantes d'internalisation des nanoparticules d'or, dépendent fortement de la lignée cellulaire. La quantité d'or internalisée résultant de ces mécanismes varie également. Ces mécanismes d’internalisation impactent la localisation des nanoparticules dans les différents organites subcellulaires, conséquence des voies spécifiques d'internalisation. Enfin un lien est proposé entre localisation intracellulaire des nanoparticules d'or et leur localisation avec les organites subcellulaires.En conclusion, ces résultats indiquent que l'efficacité des nanoparticules dépend de la lignée cancéreuse à traiter. Même si des expériences in vivo restent nécessaires à la validation de ces résultats, ce travail propose des méthodes originales qui permettent de caractériser et prévoir rapidement l’effet des agents sur les cellules. / Radiation therapy is one of the main modalities for cancer treatment. However, its use is limited due to damage induced in healthy tissues and radioresistance in some cases. However, improvements are needed to improve tumor targeting and treatment effectiveness. One of the proposed improvements is the use of nanoparticles composed of high-atomic number elements that have the property of amplifying the effect of ionizing radiation. Gold nanoparticles are one of the most promising agents, because of their low toxicity and the possibility of binding molecules on their surface. The effectiveness of small gold nanoparticles functionalized with DTDTPA (< 3 nm) has been proven. However, little data exists on the link between the amplification effects in respect to the internalization dynamics and their location in cells. This work focused on studying the internalization and excretion dynamics of these nanoparticles, as well as their location in different cancer cell lines and in human fibroblasts. An attempt to correlate the radiation effects with these data is proposed. The results obtained in this work show that the dynamics of absorption and excretion, as well as the predominant internalization pathways of gold nanoparticles, strongly depend on the cell line. The amount of internalized gold, resulting from these mechanisms, also varies. These internalization mechanisms impact the localization of nanoparticles in the various subcellular organelles, due to the specific internalization pathways. Finally, a link is proposed between the intracellular localization of gold nanoparticles and their colocalization with subcellular organelles.In conclusion, these results indicate that the effectiveness of nanoparticles depends on the cancerous line that is treated. Although in vivo experiments are still needed to validate these results, this work proposes original methods for rapid characterization and prediction of the effects of agents on cells.

OBJECTIVE: One of the major issues in current radiotherapy (RT) is the normal tissue toxicity. A smart combination of agents within the tumor would allow lowering the RT dose required while minimizing the damage to healthy tissue surrounding the tumor. We chose gold nanoparticles (GNPs) and docetaxel (DTX) as our choice of two radiosensitizing agents. They have a different mechanism of action which could lead to synergistic effect. Our first goal was to assess the variation in GNP uptake, distribution, and retention in the presence of DTX. Our second goal was to assess the therapeutic results of the triple combination, RT/GNPs/DTX. METHODS: We used HeLa and MDA-MB-231 cells for our study. Cells were incubated with GNPs (0.2nM) in the absence and presence of DTX (50nM) for 24 hrs for determination of uptake, distribution, and retention of NPs. For RT experiment, treated cells were given a 2 Gy dose of 6 MV photons using a linear accelerator. RESULTS: Concurrent treatment of DTX and GNPs resulted in over 85% retention of GNPs in tumor cells. DTX treatment also forced GNPs to be closer to the most important target, the nucleus, resulting in a significant decrease in cell survival with the triple combination of RT, GNPs, and DTX vs. RT plus DTX alone. Our experimental therapeutics results are supported by Monte Carlo simulations. CONCLUSION: The ability to not only trap GNPs at clinically feasible doses but also to retain them within the cells could lead to meaningful fractionated treatments in future combined cancer therapy. Furthermore, the suggested triple combination of RT/GNPs/DTX may allow lowering the RT dose to spare surrounding healthy tissue. ADVANCES IN KNOWLEDGE: This is the first study to show intracellular GNP transport disruption by DTX, and its advantage in radiosensitization. / Graduate / 2020-10-31

In-beam positron emission tomography (in-beam PET) is currently the only method for an in-situ monitoring of highly tumor-conformed charged hadron therapy. In such therapy, the clinical effect of deviations from treatment planning is highly minimized by implementing safety margins around the tumor and selecting proper beam portals. Nevertheless, in-beam PET is able to detect eventual, undesirable range deviations and anatomical modifications during fractionated irradiation, to verify the accuracy of the beam portal delivered and to provide the radiotherapist with an estimation of the difference in dosage if the treatment delivered differs from the planned one. In a first study within this work, a set of simulation and fully-3D reconstruction routines shows that minimizing the opening angle of a cylindrical camera is determinant for an optimum quality of the in-beam PET images. The study yields two favorite detector geometries: a closed ring or a dual-head tomograph with narrow gaps. The implementation of either detector geometry onto an isocentric, ion beam delivery (gantry) is feasible by mounting the PET scanner at the beam nozzle. The implementation of an in-beam PET scanner with the mentioned detector geometries at therapeutic sites with a fixed, horizontal beam line is also feasible. Nevertheless, knowing that previous in-beam PET research in Berkeley was abandoned due to detector activation (Bismuth Germanate, BGO), arising most probably from passive beam shaping contaminations, the proposed detector configurations had to be tested in-beam. For that, BGO was substituted with a state-of-the-art scintillator (lutetium oxyorthosilicate, LSO) and two position sensitive detectors were built. Each detector contains 32 pixels, consisting of LSO finger-like crystals coupled to avalanche photodiode arrays (APDA). In order to readout the two detectors operated in coincidence, either in standalone mode or at the GSI medical beam line, a multi-channel, zero-suppressing free, list mode data acquisition system was built.The APDA were chosen for scintillation detection instead of photomultiplier tubes (PMT) due to their higher compactness and magnetic field resistance. A magnetic field resistant detector is necessary if the in-beam PET scanner is operated close to the last beam bending magnet, due to its fringe magnetic field. This is the case at the isocentric, ion beam delivery planned for the dedicated, heavy ion hospital facility under construction in Heidelberg, Germany. In-beam imaging with the LSO/APDA detectors positioned at small target angles, both upbeam and downbeam from the target, was successful. This proves that the detectors provide a solution for the proposed next-generation, improved in-beam PET scanners. Further confirming this result are germanium-detector-based, spectroscopic gamma-ray measurements: no scintillator activation is observed in patient irradiation conditions. Although a closed ring or a dual-head tomograph with narrow gaps is expected to provide improved in-beam PET images, low count rates in in-beam PET represent a second problem to image quality. More importantly, new accelerator developments will further enhance this problem to the point of making impossible in-beam PET data taking if the present acquisition system is used. For these reasons, two random-suppression methods allowing to collect in-beam PET events even during particle extraction were tested. Image counts raised almost twofold. This proves that the methods and associated data acquisition technique provide a solution for next-generation, in-beam positron emission tomographs installed at synchrotron or cyclotron radiotherapy facilities.

Das Ziel strahlentherapeutischer Behandlung ist es, Tumoren zu vernichten und dabei das gesunde Gewebe weitgehend zu schonen. Eine Präzisions-Radiotherapie erfordert eine möglichst konforme Bestrahlung des Tumors mit der für die Heilung notwendigen Dosis. Für die heute gebräuchlichsten therapeutischen Strahlenquellen – Elektronen-Linearbeschleuniger, welche Elektronen- und harte Röntgenstrahlen bereitstellen – wurden dafür die Methoden der intensitätsmodulierten und bildgeführten Radiotherapie entwickelt. Der nächste Schritt zur Verbesserung der Tumorkonformität ist die klinische Anwendung von Partikelstrahlen (Protonen, leichte Ionen). Entsprechende Anlagen erfordern einen hohen Investitionsaufwand. Eine Reduktion dieses Aufwandes könnte der Einsatz außerordentlich kompakter Beschleunigungsstrukturen eröffnen, welche auf der Wechselwirkung hochintensiver Laserstrahlen mit Materie beruhen. / The goal of radiotherapeutic treatment is complete tumour destruction, while sparing the healthy tissue as far as possible. Precision radiotherapy requires tumour-conform irradiation with a curative dose. For electron linear accelerators, the most common therapeutic radiation source at present, delivering beams of electrons and hard X-rays, the methods of intensity-modulated and imageguided radiotherapy have been developed. The next level in improving tumour conformity is the clinical application of particle beams (protons and light ions). Such facilities require substantial investments. The outlay could be reduced, however, by using very compact accelerating structures based upon the interaction of highly intensive laser beams with matter.

Orientador: Marco Antônio Rodrigues Fernandes / Resumo: A betaterapia é uma modalidade dentro da braquiterapia que utiliza aplicadores de radiação beta, os quais são usados no tratamento de lesões superficiais. Com o avanço das técnicas terapêuticas, novos protocolos clínicos da medicina veterinária serão estabelecidos. Neste sentido, a betaterapia surge como uma opção importante para a realização de procedimentos radioterápicos e consequentente haverá estudos para definições de protocolos clínicos oncológicos. Neste trabalho é apresentada uma metodologia para determinação da distribuição de dose de radiação beta proveniente de aplicadores de estrôncio-90 (Sr90), para uso em radioterapia intraoperatória em medicina veterinária. Foram analisadas as distribuições de dose de radiação planar de três aplicadores de Sr90, por meio de filmes radiográficos, os quais foram expostos aos feixes oriundos das fontes em diferentes tempos de exposição. Foi verificada a densidade óptica (D.O.) do campo de radiação por um densitômetro digital. Após o escaneamento dos filmes, com o uso do software ImageJ, foram medidas as intensidades de brilho referente aos campos de exposição da radiação. A análise da distribuição de dose de radiação dos aplicadores de betaterapia, produziu resultados semelhantes aos apresentados na literatura. O uso do software ImageJ, assim como a D.O. obtida auxiliaram na análise dos estudos dosimétricos. Os comportamentos das curvas de dose-efeito proporcionaram maior compreensão da homogeneidade do campo de radiação no plano... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Beta therapy is a modality within brachytherapy that utilizes beta radiation applicators, which are used in the treatment of superficial injuries. The advance of radiotherapy techniques allows the establishment of new clinical protocols of veterinary medicine will be established. Beta therapy appears as an important option for performing radiotherapy procedures and, consequently, there will be studies for the definition of clinical oncological protocols. This study presents a methodology for determining the dose distribution of beta radiation from strontium90 applicators (Sr90) for use in intraoperative radiotherapy in veterinary medicine. The planar radiation dose distributions of three Sr90 applicators were analyzed by radiographic films, to which they were exposed to beams from sources at different exposure times. The optical density (O.D.) of the radiation field was verified by a digital densitometer. After scanning the films, ImageJ software measured the brightness intensity of the radiation exposure fields. The radiation dose distribution analysis of the beta therapy applicators produced results similar to those presented in the literature. The use of ImageJ software, as well as O.D. obtained helped in the analysis of dosimetric studies. The behaviors of the dose-effect curves provided a better understanding of the radiation field homogeneity in the treatment plan, thus, the radiation dose distributions in the treatment fields indicate the use of these types of applicat... (Complete abstract click electronic access below) / Doutor

It has long been known that oxygen has the potential to be toxic to biologic systems and that this toxicity is not due to oxygen itself, but due to the production of oxygen radicals. One of these potentially toxic radicals, superoxide (O₂⁻) can be generated as a result of ionizing radiation, and if not adequately removed can proceed to cause cell damage. Superoxide dismutase (SOD) is one of the key enzymes involved in the defence against oxygen toxicity. SOD activity can be inhibited by diethyldithiocarbamate (DOC), a powerful copper chelator. If inhibition of SOD by DOC increases the lifetime and effectiveness of radiation induced O₂⁻, it follows that the potential exists for DOC to enhance the effect of radiation. DOC is however also a thiol compound, and thus may act as a radioprotector by modifying tissue oxygenation status or by free radical scavenging. This study has concerned itself primarily with the inhibition of superoxide dismutase by diethyldithiocarbamate in order to sensitize tumours to ionizing radiation. The use of DOC as an inhibitor of SOD has however meant that any sensitization resulting from SOD inhibition could be masked by a radioprotective effect by DOC. The inhibition of SOD by DDC was confirmed in a murine rhabdomyosarcoma, and it was shown that this inhibition can be maintained for up to twenty-four hours after DDC administration. It was hypothesised that there was a potential for the radioprotective effect of DDC to be overcome, if the levels of DDC were low enough at the time of irradiation. Indeed, if DDC was removed from the growth medium of B16 mouse melanoma cells in culture prior to irradiation, a significant sensitization was demonstrated. It was shown that DDC could act as both a radiosensitizer and as a radioprotector in the same experiment. The dominant action of DDC was found to be dependent on the time allowed between DDC administration and irradiation. If this time was approximately 4 hours, it was possible to show a radiosensitizing effect by means of a tumour growth delay assay. This time modulation effect of DOC was shown in larger tumours, rather than smaller tumours, which could indicate that tumour oxygenation is an important criterion in determining the response to radiation of DOC treated cells. It was shown that B16 mouse melanoma cells exposed to 43°C after DDC pre-treatment were sensitized to thermal damage. This work suggests that some caution should be exercised when DDC is put forward as either a radiosensitizer or a radioprotector in the clinic, but that DDC may have potential as a thermosensitizer.

La recherche concernant l’utilisation de nanoparticules dans le domaine médical a connu un essor considérable ces vingt dernières années, notamment dans le cadre du traitement du cancer. En particulier, l’effet radiosensibilisant des nanoparticules métalliques a été beaucoup étudié en radiothérapie, dans une perspective de réduction des effets secondaires générés par l’irradiation des tissus sains autour de la tumeur. Dans ce travail, nous nous sommes intéressés à des nanoparticules d’or greffées d’une couronne polymère. Celle-ci assure une grande stabilité des objets, tout en permettant de faire varier leurs propriétés physico-chimiques et d’en étudier l’impact sur leur comportement. Les polymères utilisés sont des polyméthacrylates, obtenus par polymérisation radicalaire contrôlée, qui jouent le rôle de ligands lors de la synthèse des nanoparticules d’or. Nous avons pu faire varier deux paramètres, la masse molaire et la nature chimique des (co)polymères, afin de constituer une gamme de nano-objets aux propriétés différentes. Une caractérisation approfondie, notamment par diffusion de rayonnements aux petits angles, a mis en évidence une structure similaire pour l’ensemble des objets synthétisés. Un agent de chimiothérapie, la doxorubicine, et deux protéines ont en outre pu être greffés sur les ligands polymères. Les interactions de ces différentes nanoparticules avec les systèmes biologiques ont été étudiées de manière détaillée, en particulier l’impact des propriétés de la couronne polymère. Quatre aspects ont été examinés : la stabilité colloïdale en milieux biologiques, la capacité à diffuser dans la matrice extracellulaire, la captation cellulaire et la cytotoxicité. Tous les ligands étudiés assurent une bonne stabilité. Concernant les autres aspects, la comparaison systématique des résultats obtenus pour la gamme d’objets a permis de mettre en évidence un fort impact de la nature de la couronne polymère, notamment de la présence de charges positives ou de segments hydrophobes. Nous avons également montré que les propriétés de toxicité de la doxorubicine, et de captation accrue d’une protéine étaient bien conservées après greffage. Dans une perspective d’utilisation en radiosensibilisation, nous avons enfin étudié le comportement de nos nanoparticules sous irradiation. Une bonne stabilité de leur structure a été observée sous rayonnement, et leur association à l’iode 131 (radiothérapie interne) a montré un fort effet radiosensibilisant, à la fois in vitro et in vivo. Les résultats des essais menés en protonthérapie (radiothérapie externe) mettent cependant en évidence des différences de comportements selon le type d’irradiation. Nous avons également exploré la possibilité de détecter les nanoparticules in situ, lors d’une irradiation en protonthérapie, grâce à l’analyse des rayons X émis. / These past twenty years, there has been a great increase in the number of studies concerning the use of nanoparticles for medical applications, especially for cancer treatment. In particular, radiosensitizing effects of metal nanoparticles have been studied a lot in radiotherapy, in order to reduce the side effects created by the irradiation of healthy tissues surrounding the tumor. In this work, we focused on polymer-grafted gold nanoparticles. The polymer corona both ensured a great stability of the objects and allowed to change their physico-chemical properties, in order to study their impact on the nanoparticles behavior. We used polymethacrylates which were obtained through controlled radical polymerization and acted as ligands during the gold nanoparticles synthesis. A library of nano-objects with different properties was established by varying both molar mass and chemical nature of (co)polymers. Thorough characterization, including by small-angle radiation scattering, revealed similar structures for all synthesized objects. Grafting of one chemotherapy agent, doxorubicin, and two proteins was also performed on polymer ligands. Interactions between these various nanoparticles and biological systems were studied in detail. Special attention was given to the impact of polymer corona properties. Four aspects were examined: colloidal stability in biological media, ability to diffuse inside the extracellular matrix, cellular uptake, and cytotoxicity. All studied ligands ensured a great stability. Regarding the other aspects, systematic comparison of the results obtained for the whole library highlighted a strong impact of the ligands nature, especially the presence of positive charges or hydrophobic segments. We have also shown that grafted doxorubicin and protein kept their toxic and targeting properties respectively. Lastly, the prospect of using these nanoparticles for radiosensitization led us to study their behavior under radiations. When irradiated, their structure was found stable. Combining them with radioiodine (internal radiotherapy) showed a great radiosensitizing effect, both in vitro and in vivo, but experiments with protontherapy (external radiotherapy) revealed different behaviors depending on the type of radiations. We also investigated the use of particle-induced X-ray emission to detect nanoparticles in situ, during protontherapy treatment.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaf 186. / by Thomas James Miller, Jr. / M.S.