Les thérapies moléculaires ciblées ont changé la prise en charge des patients atteints de cancer, et en particulier dans le cancer colorectal (CCR). Il est important d’identifier des biomarqueurs de sensibilité ou de résistance à ces traitements. En premier, la signalisation en aval de l’EGFR au niveau tumoral pourrait conditionner la réponse au cétuximab dans les cancers colorectaux (CCR). Notre premier travail a évalué le niveau d’expression tumorale de phosphoprotéines de signalisation en aval de l’EGFR (p-MEK, p-ERK1/2, p-AKT, p-GSK3b, p-P70S6K) analysés par Bioplex phosphoprotein array chez 42 patients avec un CCR métastatique, traités par anti-EGFR. L’expression de p-P70S6K est plus faible chez les patients répondeurs (p=0,02). La survie sans progression (SSP) est supérieure en cas d’expression faible de p-P70S6K (p=0,0001) et p-MEK (p=0,0006). p-MEK et p-P70S6K ont une expression plus élevée chez les KRAS mutés et apparaissent comme deux marqueurs pronostiques indépendants de KRAS (HR 0,34, p=0,01 et HR 0,42, p=0,03). Ainsi, le niveau d’expression des phosphoprotéines en aval de l’EGFR pourrait prédire la réponse et la SSP dans les CCR traités par anti-EGFR, indépendamment du statut KRAS. Il est difficile dans certain cas d’avoir accès au tissu tumoral. L’ADN circulant (cADN) dans les stades avancés de cancer peut aider à la caractérisation moléculaire des tumeurs, en tant que biopsie. Notre deuxième travail a étudié la faisabilité, la sensibilité et la spécificité d’une technique de spectrométrie de masse (Sequenom) pour détecter des mutations (238 mutations parmi 19 oncogènes) à partir du tissu tumoral et du cADN de 105 patients ayant un cancer avancé. La concentration médiane de cADN était de 17ng/ml de plasma (0,5-1600), soit 3 fois le niveau chez les volontaires sains. En analyse multivariée, la concentration de cADN, l’albumine et l’état général étaient des facteurs prédictifs indépendants de la survie globale des patients. De plus, il existait une concordance élevée des statuts mutationnels (KRAS, BRAF et PIK3CA) entre le tissu tumoral et le cADN dans plusieurs types tumoraux (CCR, sein, mélanome): un taux de concordance de 70% pour le gène KRAS et de 100% pour le gène BRAF ont été retrouvés dans le CCR. Notre Étude suggère que l’analyse du cADN pourrait être un matériel utilisable pour la recherche de mutations, notamment dans le suivi des patients ayant un cancer du colon traités par thérapies ciblées. Notre travail a donc montré l’intérêt de poursuivre l’étude de facteurs moléculaires qui pourraient prédire la réponse ou la résistance à des thérapies ciblées utilisées dans les cancers du colon, au niveau du tissu tumoral (phosphoprotéines) ou au niveau du sang (cADN). / Especially in CRC, it is important to identify molecular targeted therapies biomarkers. First, additional markers of resistance to KRAS mutations could predict resistance to anti-epidermal growth factor receptor (EGFR) antibodies in advanced colorectal cancer (CRC). In our first study, in a series of 42 patients with advanced CRC treated with cetuximab/panitumumab, for whom KRAS status was previously determined, we retrospectively analyzed the intratumor expression of EGFR downstream signaling phosphoproteins of the RAS/MAPK and PI3K/AKT pathways (pERK1/2, pMEK1, pAKT, pP70S6K and pGSK3beta) using Bio-Plex phosphoprotein array. The expression of all the phosphoproteins was higher in KRAS mutated tumors than in WT tumors. The expression of pP70S6K was lower in responders than in nonresponder patients. In multivariate analysis, PFS was shorter for patients with high pMEK1 or pP70S6K expression, independently of KRAS status, as OS for patients with high pP70S6K expression. Our results suggest the importance of EGFR downstream signaling phosphoproteins expression in addition to KRAS status to define the subgroup of patients who will not benefit from anti-EGFR therapy. We hypothesized that circulating plasma DNA (cpDNA) in advanced cancer patients is largely derived from tumor, and can be utilized for tumor mutation sequencing when repeat biopsy is not feasible. In our second study, we utilized the Sequenom MassArray System and OncoCarta panel for somatic mutation profiling. Matched samples, acquired from the same patient but at different time points were evaluated; these comprised formalin-fixed paraffin-embedded (FFPE) archival tumor tissue (primary and/or metastatic) and cpDNA. The feasibility, sensitivity, and specificity of this high-throughput, multiplex mutation detection approach was tested utilizing specimens acquired from 105 patients with solid tumors referred for participation in Phase I trials of molecularly targeted drugs. The median cpDNA concentration was 17 ng/ml (range: 0.5-1600); this was 3-fold higher than in healthy volunteers. In multivariate analyses, cpDNA concentration, albumin, and performance status remained independent predictors of OS. We also observed high detection concordance for critical "hot-spot" mutations (70% for KRAS, 100% for BRAF) in matched cpDNA and archival tumor tissue. This multiplex sequencing assay can be utilized to detectsomatic mutations from plasma in advanced cancer patients, when safe repeat tumor biopsy is not feasible and genomic analysis of archival tumor is deemed insufficient. Our work did show the importance to search for molecular markers to predict response to targeted therapies, both in tumor tissu (phosphoproteins) and in blood (cpDNA).

Le cancer broncho-pulmonaire du non-fumeur est considéré comme une entité à part du fait de ses particularités épidémiologiques. Il est en outre un excellent modèle pour l'étude des facteurs de risque de cancer bronchique autres que le tabagisme actif. Il n'existe que très peu de données non-asiatiques concernant cette entité d'intérêt. Le bio-observatoire national des cancers bronchiques de non-fumeurs (BioCAST I IFCT-1002) est une étude épidémiologique multicentrique prospective. Son objectif principal est de décrire une population de patient strictement non-fumeur (moins de 100 cigarettes au cours de la vie) atteint de cancer bronchique, notamment sur le plan de leur profil moléculaire somatique et de leur exposition aux facteurs de risque. Les objectifs secondaires étaient d'étudier si l'exposition aux différents facteurs de risque pouvait influencer le profil moléculaire ; et d'utiliser cette cohorte particulière (grande fréquence et diversité de mutations somatiques attendue) afin de développer un test multiplex pour le diagnostic non-invasif du profil moléculaire somatique tumoral à partir d'ADN circulant. Au total, 384 patients non-fumeurs atteints de cancer broncho-pulmonaire ont été inclus dans cette cohorte. Deux-tiers d'entre eux étaient exposés au tabagisme passif, et il s'agissait essentiellement d'une exposition domestique touchant les femmes. Inversement, 35% des hommes étaient exposés de manière certaine à au moins un cancérogène professionnel, contre 8% des femmes. Au total, 72% des patients présentait une anomalie moléculaire, essentiellement au niveau de l'EGFR (51% de l'ensemble de la cohorte). Le genre, ou l'exposition à différents facteurs de risque (tabagisme passif, exposition professionnelle, exposition hormonale chez les femmes) n'affectait pas de manière significative et cliniquement pertinente le profil mutationnel, avec les limites liée à de faibles effectifs dans certains groupes et aux expositions multiples. Seule l'exposition professionnelle à l'amiante et / ou à la silice semble avoir pour effet de diminuer la fréquence des mutations de l'EGFR / Lung cancer in never smokers (LCINS) is considered as a separate entity given its epidemiological specificities. It is also a very interesting template to assess alternative risk factors for lung cancers than tobacco smoking. However, there is very little non-Asian data about this particular topic. The BioCAST / IFCT1002 study is a prospective, nationwide, and multi-centric epidemiological study. Its main objective was to describe a French population of lung cancers in lifelong never smokers (less than 100 cigarette during all lifetime); with a special focus on molecular somatic profile and risk-factors exposure. Secondary objectives were to assess the interaction between risk-factor exposure and molecular profile; and to use this particular cohort to develop a multiplex test for non-invasive diagnosis of tumor mutations in circulating free DNA. Overall, 384 patients were recruited in the cohort. Two-third were exposed to passive smoking (mainly women and in domestic setting). By contrast, 35% of men were definitely exposed to occupational carcinogens versus 8% of women. Finally, 72% were found with a somatic mutation, mainly in the EGFR gene (51% of the whole population). Gender or exposure to risk factors such as passive smoking, occupational exposure, or hormonal status in women, were not significantly associated with a specific and/or clinically meaningful molecular profile in tumor. These findings should be interpreted with caution given that some subgroups were small and/or with many simultaneous exposures. However, exposure to asbestos and/or silica was significantly associated to a decreased risk for EGFR mutation. On the pilot study (n=106), circulating free DNA was associated with tumor burden. The multiplex diagnosis (12 amplicons on 5 genes) by next-generation sequencing was feasible and gave encouraging results in stage 4 patients (67% sensitivity, 73% concordance rate). LCINS is an interesting entity for the study of non-tobacco-related cancer risk factors; or to optimize liquid biopsy strategy

This master’s thesis deals with design of the regulation of a circulating pump in a solar system for heating of supply water and design of the regulator for this system. It describes a fundamental principle and layout of a regulated circuit of a heating system. Description of regulation, basic terms, properties and differences between different types of regulation are described in first part of the master’s project. Especially continuous (PID regulator) and discrete (PSD regulator) regulation are presented. Second part of the master’s project is focused on a conceptual design of the circulating pump regulator. The connection system of each part, selection conditions of components and connection scheme of regulator are described. The third section deals with design of controlling algorithm of the regulator. There is a detailed description of libraries and functions in each chapter which were used in programming of PSD regulator algorithm. The regulated system of a solar collector is described at the end of the work. This system is being developed for real testing and setting of regulator.

L'ADN tumoral circulant (ADNtumc) est apparu depuis plusieurs années comme un biomarqueur prometteur susceptible d'apporter des informations permettant l'optimisation de la prise en charge du patient en oncologie. L'objectif de cette thèse était double et s'articule autour de deux axes : i) évaluer différentes conditions préanalytiques et analytiques (digitale PCR (dPCR) principalement) pour la détection de ce biomarqueur ii) évaluer l'intérêt clinique potentiel de ce biomarqueur en oncologie digestive. La première partie rapporte 3 travaux (3 articles originaux dont une collaboration nationale (équipe parisienne dirigée par J. Tost)). Dans le travail n°1, nous avons montré la faisabilité de détecter l'ADNtumc par dPCR directement à partir du plasma de 43 prélèvements de patients avec cancer colorectal métastatique (CCRm). Il n'y avait pas de différence significative pour le taux de détection des mutations KRAS circulantes entre les groupes avec et sans extraction d'ADN (93 % (40/43) versus 88 °A) (38/43), respectivement). Dans le travail n°2, nous avons mis au point une méthode basée sur l'apport d'héparinase pour la détection d'ADNtumc à partir de 194 prélèvements héparinés de patients suivis en oncologie. Ce traitement des échantillons par l'héparinase permettait l'analyse de l'ADNtumc pour 117/194 (60 %) patients avec inhibition Préalable de la dPCR par l'héparine. Enfin, dans le travail n°3, nous avons comparé plusieurs plate-formes de détection d'ADNtumc et montré que la dPCR affichait des résultats de détection comparables sur le plan qualitatif et quantitatif avec une plateforme ultrasensible d'Enhanced-ice-COLD-PCR (E-ice-COLD-PCR) pour les échantillons avec une fréquence allélique d'ADNtumc >0,4 °A La deuxième partie rapporte 3 travaux (3 articles originaux) sur l'intérêt clinique de la détection d'ADNtumc par dPCR en oncologie digestive. Nous avons ainsi montré que ce biomarqueur conférait un intérêt diagnostique (travail n°4), Pronostique (travail n 4 à 6) et prédictif de la réponse aux traitements (travail n°6) chez les Patients avec adénocarcinome pancréatique (AP) (travail n°4) et CCRm (travail n°5 à 6). / For several years, circulating tumor DNA (ctDNA) has emerged as a promising biomarker providing relevant information to optimize patient care in oncology. The aim of this thesis was both: (i) to evaluate different preanalytical and analytical conditions (digital PCR (dPCR) mainly) for the detection of this biomarker; (ii) to evaluate the potential clinical interest of this biomarker in digestive oncology. The first part reports 3 works (3 original articles including a national collaboration (Parisian team led by J. lost)). In work no. 1, we have shown the feasibility of ctDNA detection by dPCR directly from the plasma of 43 samples from patients with metastatic colorectal cancer (mCRC). There was no significant difference in the detection rate of circulating KRAS mutations between groups with and without DNA extraction (93% (40/43) versus 88% (38/43), respectively). In work no. 2, we developed a method based on the heparinase addition for the ctDNA detection from 194 heparinized samples of patients followed in oncology. This treatment of samples by heparinase allowed the ctDNA analysis of 117/194 (60%) patients with prior inhibition of dPCR by heparin. Finally, in work no. 3, we compared several ctDNA detection platforms and snowed that dPCR displayed qualitatively and quantitatively comparable detection results with an ultrasensitive platform of E-ice-COLD-PCR for the samples with ctDNA allelic fraction ?.0 4%. The second part reports 3 works (3 original articles) on the clinical interest of the ctDNA detection by dPCR in digestive oncology. We have thus shown that this biomarker had a diagnostic (work no. 4). prognostic (works no. 4 to 6) and predictive response to treatments (work no. 6) interest in patients with pancreatic adenocarcinoma (work no. 4) and mCRC (works no. 5 to 6).

Les cellules tumorales circulantes (CTC) représentent un large champ de recherche susceptible de fournir des informations tant cliniques que fondamentales. Les CTC proviennent de tumeurs primitives ou métastatiques et représentent une population hétérogène de cellules très rares dans le flux sanguin. Leur caractérisation moléculaire est un défi technologique qui requiert des méthodes très sensibles et spécifiques. Dans les cancers bronchiques non à petites cellules (CBNPC), les CTC ont un véritable intérêt car les biopsies tumorales ne permettent pas toujours de réaliser les analyses moléculaires nécessaires au choix du traitement. De plus, elles ne sont probablement pas représentatives de l’hétérogénéité tumorale.L’objectif de ma thèse a été de rechercher dans les CTC de patients atteints de CBNPC porteurs du remaniement de gène ALK, des anomalies génomiques connues pour être des biomarqueurs de sensibilité et de résistance aux thérapies ciblant cet oncogéne, ainsi qu’à caractériser les CTC porteuses de ces anomalies. La première partie du projet a consisté au développement d’une méthode d’hybridation in situ de l’ADN (fluorescent in situ hybridization, FISH) adaptée à un système d’enrichissement des CTC par filtration, la FA-FISH (filter adapted FISH) (brevet PCT/FR2011/052688). Nous avons ensuite développé une approche de microscopie semi-automatisée permettant la digitalisation et l’analyse de ces CTC enrichies par filtration (Pailler, BMC Cancer, 2016). Dans la seconde partie du projet, nous avons mis en œuvre cette méthode et montré pour la première fois qu’il est possible d’identifier le remaniement de gène ALK dans les CTC de patients porteurs de ce réarrangement dans la tumeur (Pailler, J Clin Oncol, 2013). Les CTC remaniées présentent un unique réarrangement de type break-apart, y compris chez des patients présentant exclusivement une autre forme de réarrangement dans la tumeur, et un phénotype mésenchymateux. Cette observation nous a amené à émettre l’hypothèse que ces CTC ont acquis des propriétés migratoires et d’invasivité, et pourraient résulter d’une forte sélection clonale. Nous avons ensuite étendu cette observation aux patients porteurs du remaniement ROS1 et rapporté pour la première fois la détection de ce remaniement dans des CTC (Pailler, Ann Oncol, 2015). Dans la troisième partie du projet, nous avons émis l’hypothèse que certaines sous-populations de CTC anormales pour le gène ALK, mesurées avant et à deux mois de traitement par le crizotinib, pourraient prédire l’évolution clinique des patients traités. Dans une cohorte élargie de patients, nous avons montré que l’évolution sous crizotinib du nombre de CTC présentant exclusivement des gains de copies natives du gène ALK est un biomarqueur « surrogate » d’efficacité du traitement pouvant permettre d’identifier les patients qui ont un risque élevé de progresser rapidement (Pailler, soumis). Finalement, dans la quatrième partie du projet, nous avons recherché dans des CTC des mutations de résistance aux inhibiteurs de ALK. Nous avons mis au point des technologies permettant de caractériser phénotypiquement, isoler et analyser moléculairement (séquençages ciblés et d’exomes) des CTC à l’échelle de cellule unique. Les expériences sur lignées cellulaires ont permis de valider les approches et les analyses d’échantillons de patients sont en cours.Dans ce travail, nous montrons qu’il est possible de caractériser des anomalies génomiques dans les CTC de patients porteurs du remaniement ALK à différentes étapes de leur maladie, et ainsi d’identifier des biomarqueurs de sensibilité et d’efficacité à une thérapie ciblée. Ce travail ouvre des perspectives sur la personnalisation des traitements qui pourraient reposer sur l’analyse génomique non invasive des CTC. Il apporte en outre des éléments nouveaux sur les caractéristiques biologiques des CTC chez ces patients, certaines étapes du processus métastatique et la diversité génomique de ces cancers. / Circulating tumor cells (CTCs) are a broad field of research which may provide both clinical and basic information. CTCs migrate from primitive or metastatic tumors and represent a heterogeneous population of very rare cells in the blood stream. The molecular characterization of CTCs is a technical challenge requiring highly sensitive and specific methods. Because tumor biopsies are invasive and in some cases associated with risk in non-small-cell lung cancer (NSCLC), CTCs may offer an attractive option to analyze tumor genomic alterations and detect molecular biomarkers. CTCs could provide a more comprehensive picture of the tumor content than single tumor biopsies.The aim of my thesis was to characterize genomic abnormalities in CTCs from ALK-rearranged NSCLC patients and identified biomarkers of sensitivity and resistance to targeted therapies. The first part of the project consisted in the development of a fluorescent in situ hybridization (FISH) method adapted to CTCs enriched by filtration, the FA-FISH (filter-adapted-FISH) (patent PCT/FR2011/052688). Then, we developed a method for the semi-automated microscopy of filtration enriched CTCs (Pailler, BMC Cancer, 2016). In the second part of my project, using this method, we provided the first proof-of-concept that ALK-rearrangement can be detected in CTCs of patients with ALK-rearranged NSCLC (Pailler, J Clin Oncol, 2013). We showed that CTCs from these patients harbor a unique ALK break-apart rearrangement, including patients presenting another form of rearrangement in the biopsy, and a mesenchymal phenotype. This suggests that these CTCs may arise from a clonal selection of tumor cells that have acquired invasive and migratory properties and possibly the potential to drive metastatic progression. Then, we characterized CTCs from patients with ROS1-rearranged NSCLC and reported for the first time the detection of ROS1-rearrangement in CTCs (Pailler, Ann Oncol, 2015). In the third part of the project, we evaluated whether CTCs with abnormal ALK-FISH patterns monitored under crizotinib (baseline and early sampling at 2 months) may inform on treatment benefit in a cohort of ALK-rearranged patients treated by crizotinib. In an extended cohort of patients, the dynamic change in the numbers of CTCs with a gain of ALK-native copies was associated with the progression-free survival and thus may be a surrogate biomarker for crizotinib efficacy (Pailler, submitted). These results show that the molecular analysis of CTCs performed under treatment could help to stratify patients at risk of early resistance to crizotinib. Finally, in the last part of my project, we sought to evaluate whether CTCs could be used for identifying resistance mutations to ALK inhibitors. We developed technologies to characterize, isolate and molecularly (targeted sequencing and exome sequencing) analyze CTCs at the single cell level. Experiments on cell lines allowed to validate these technical processes; Experiments on patient samples are ongoing.In this work, we characterize genomic abnormalities present in CTCs from ALK-rearranged patients at different stages of the disease and identify biomarkers of sensitivity and efficacy to targeted therapies. Our results provide new perspectives on the potential of CTCs for personalizing treatments in NSCLC patients. Furthermore, our findings may offer new insights on the biological characteristics of CTCs in ALK-rearranged patients, their overall role in the metastatic progression and the genomic diversity of these cancers.

Indiana University-Purdue University Indianapolis (IUPUI) / Triple-negative breast cancers (TNBCs) are pathologically defined by the absence of estrogen, progesterone, and HER2 receptors. Compared to other breast cancers, TNBC has a relatively high mortality. In addition, TNBC patients are more likely to relapse in the first few years after treatment, and experiencing a shorter median time from recurrence to death. Detecting the presence of tumor in patients who are technically “disease-free” after neoadjuvant chemotherapy and surgery as early as possible might be able to predict recurrence of patients, and then provide timely intervention for additional therapy. To this end, I applied the analysis of “liquid biopsies” for early detection of minimal residual disease (MRD) on early-stage TNBC patients using next-generation sequencing. For the first part of this study, I focused on detecting circulating tumor DNA (ctDNA) from TNBC patients after neoadjuvant chemotherapy and surgery. First, patient-specific somatic mutations were identified by sequencing primary tumors. From these data, 82% of the patients had at least one TP53 mutation, followed by 16% of the patients having at least one PIK3CA mutation. Next, I sequenced matched plasma samples collected after surgery to identify ctDNA with the same mutations. I observed that by detecting corresponding ctDNA I was able to predict rapid recurrence, but not distant recurrence. To increase the sensitivity of MRD detection, in the second part I developed a strategy to co-detect ctDNA along with circulating tumor RNA (ctRNA). An advantage of ctRNA is its active release into the circulation from living cancer cells. Preliminary data showed that more mutant molecules were identified after incorporating ctRNA with ctDNA detection in a metastatic breast cancer setting. A validation study in early-stage TNBC is in progress. In summary, my study suggests that co-detection of ctDNA and ctRNA could be a potential solution for the early detection of disease recurrence. / 2021-08-05

1 ABSTRACT Introduction and aim of the study Circulating tumor cells (CTCs) are a promising tool of identifying patients with castration- resistant prostate cancer (CRPC) who will benefit from often demanding cytotoxic therapy. The aim of this work was to evaluate the prognostic significance of CTC in docetaxel-treated CRPC patients. During the project, we also tested the various methods of CTC cultivation and studied their genetic profile as well as the genetic profile of histological specimen at the time of diagnosis. Patients and methods A total of 39 patients who met the CRPC criteria and were indicated for docetaxel chemotherapy were included in the prospective study. Blood collection for CTC analysis was done in all patients before chemotherapy and on the first day of the fourth or fifth cycle of docetaxel. In parallel, CTCs were cultivated. Isolation and detection of CTC was done using the AdnaTest system, which consists of immunomagnetic separation and subsequent detection of mRNA from the CTC lysate. The primary objective of the study was to evaluate the overall survival (OS) of patients. Survival analysis was performed using the Kaplan-Meier method of estimating the survival distribution function. The impact of individual factors was tested using the Log-rank test, the Wilcoxon test and the Cox...

Circulating tumor cells (CTCs) are a potential predictive surrogate marker for disease monitoring. Due to the sparse knowledge about their phenotype and its changes during cancer progression and treatment response, CTC isolation remains challenging. Here we focused on the mechanical characterization of circulating non-hematopoietic cells from breast cancer patients to evaluate its utility for CTC detection. For proof of premise, we used healthy peripheral blood mononuclear cells (PBMCs), human MDA-MB 231 breast cancer cells and human HL-60 leukemia cells to create a CTC model system. For translational experiments CD45 negative cells—possible CTCs—were isolated from blood samples of patients with mamma carcinoma. Cells were mechanically characterized in the optical stretcher (OS). Active and passive cell mechanical data were related with physiological descriptors by a random forest (RF) classifier to identify cell type specific properties. Cancer cells were well distinguishable from PBMC in cell line tests. Analysis of clinical samples revealed that in PBMC the elliptic deformation was significantly increased compared to non-hematopoietic cells. Interestingly, non-hematopoietic cells showed significantly higher shape restoration. Based on Kelvin–Voigt modeling, the RF algorithm revealed that elliptic deformation and shape restoration were crucial parameters and that the OS discriminated non-hematopoietic cells from PBMC with an accuracy of 0.69, a sensitivity of 0.74, and specificity of 0.63. The CD45 negative cell population in the blood of breast cancer patients is mechanically distinguishable from healthy PBMC. Together with cell morphology, the mechanical fingerprint might be an appropriate tool for marker-free CTC detection.

Despite significant improvements in medical sciences over the last decade, cancer still continues to be a major cause of death in humans throughout the world. Parallel to the efforts of understanding the intricacies of cancer biology, researchers are continuously striving to develop effective cancer detection and treatment strategies. Use of nanotechnology in the modern era opens up a wide range of possibilities for diagnostics, therapies and preventive measures for cancer management. Although, existing strategies of cancer detection and treatment, using nanoparticles, have been proven successful in case of cancer imaging and targeted drug deliveries, they are often limited by poor sensitivity, lack of specificity, complex sample preparation efforts and inherent toxicities associated with the nanoparticles, especially in case of in-vivo applications. Moreover, the detection of cancer is not necessarily integrated with treatment. X-rays have long been used in radiation therapy to kill cancer cells and also for imaging tumors inside the body using nanoparticles as contrast agents. However, X-rays, in combination with nanoparticles, can also be used for cancer diagnosis by detecting cancer biomarkers and circulating tumor cells. Moreover, the use of nanoparticles can also enhance the efficacy of X-ray radiation therapy for cancer treatment. This dissertation describes a novel in vitro technique for cancer detection and treatment using X-ray radiation and nanoparticles. Surfaces of synthesized metallic nanoparticles have been modified with appropriate ligands to specifically target cancer cells and biomarkers in vitro. Characteristic X-ray fluorescence signals from the X-ray irradiated nanoparticles are then used for detecting the presence of cancer. The method enables simultaneous detection of multiple iv cancer biomarkers allowing accurate diagnosis and early detection of cancer. Circulating tumor cells, which are the primary indicators of cancer metastasis, have also been detected where the use of magnetic nanoparticles allows enrichment of rare cancer cells prior to detection. The approach is unique in that it integrates cancer detection and treatment under one platform, since, X-rays have been shown to effectively kill cancer cells through radiation induced DNA damage. Due to high penetrating power of X-rays, the method has potential applications for in vivo detection and treatment of deeply buried cancers in humans. The effect of nanoparticle toxicity on multiple cell types has been investigated using conventional cytotoxicity assays for both unmodified nanoparticles as well as nanoparticles modified with a variety of surface coatings. Appropriate surface modifications have significantly reduced inherent toxicity of nanoparticles, providing possibilities for future clinical applications. To investigate cellular damages caused by X-ray radiation, an on-chip biodosimeter has been fabricated based on three dimensional microtissues which allows direct monitoring of responses to X-ray exposure for multiple mammalian cell types. Damage to tumor cells caused by X-rays is known to be significantly higher in presence of nanoparticles which act as radiosensitizers and enhance localized radiation doses. An analytical approach is used to investigate the various parameters that affect the radiosensitizing properties of the nanoparticles. The results can be used to increase the efficacy of nanoparticle aided X-ray radiation therapy for cancer treatment by appropriate choice of X-ray beam energy, nanoparticle size, material composition and location of nanoparticle with respect to the tumor cell nucleus.

No description available.