O presente estudo visa descrever a farmacocinética, o metabolismo e a excreção renal da doxorrubicina, uma antraciclina utilizada no tratamento do câncer de mama. A doxorrubicina é biotransformada a doxorrubicinol pelas enzimas carbonil redutase 1 e 3 e aldo-ceto redutase. Foram investigadas 12 pacientes portadoras de câncer de mama no primeiro ciclo de tratamento adjuvante ou neoadjuvante com doxorrubicina (60 mg/m2) administrada por infusão intravenosa durante 30 min. As amostras seriadas de sangue foram colhidas até 48 h após o início da infusão e a urina foi coletada em intervalos de 4 h por 48 h. Os métodos de análise da doxorrubicina e doxorrubicinol em urina e em plasma como concentração total e concentração livre foram desenvolvidos empregando LC-MS/MS. Os métodos não apresentaram efeito matriz ou efeito residual e mostraram-se lineares para ambos os analitos nos intervalos de 0,4-200 ng/mL para concentração total em plasma; 0,4-40 ng/mL para concentração livre em plasma e 20-8000 ng/mL de urina. Os parâmetros farmacocinéticos da doxorrubicina foram calculados com base nas curvas de concentração plasmática total versus tempo empregando o programa Phoenix® WinNonlin® por modelo tricompartimental com observação de meias-vidas de distribuição, de eliminação rápida e de eliminação terminal de 0,10; 2,55 e 40,87 h, respectivamente. A fração livre de doxorrubicina foi de 16,05% e de doxorrubicinol de 17,34%. A fração da dose de doxorrubicina recuperada na urina (0-48 h) foi de 2,35% para o fármaco inalterado e de 1,35% para o fármaco metabolizado a doxorrubicinol. Os valores médios de clearances na população do estudo foram de 58,07 L/h para o total, 1,45 L/h para o renal, 56,62 L/h para o hepático e 0,71 L/h para o clearance de formação do metabólito doxorrubicinol. Logo, os dados inferem que a eliminação da doxorrubicina é preponderantemente biliar. Os valores de clearance total não corrigidos em função do peso ou área superficial corpórea mostraram coeficiente de variação de 95,32%, enquanto para valores de clearance total corrigidos em função do peso ou da área superficial corpórea, foram obtidos valores similares, respectivamente, 88,74% e 89,84%. O estudo detalhado da farmacocinética da doxorrubicina e seu metabólito doxorrubicinol permitiu, pela primeira vez, o cálculo da razão de extração hepática (E=0,63) em humanos, classificando a doxorrubicina como um fármaco de extração hepática intermediária. / The aim of this study is to describe the pharmacokinetics, metabolism and renal excretion of doxorubicin, an anthracycline used in breast cancer treatment. Doxorubicin is metabolised to doxorrubicinol by carbonyl reductase 1 and 3, and aldo-keto reductase enzymes. Twelve breast cancer patients with indication of adjuvant or neoadjuvant treatment were assessed during the first cycle of doxorubicin administration (60 mg/m2, iv-infusion, 30 min). Serial blood samples were collected up to 48 hours after the start of iv-infusion; urine was collected in 4-hour intervals, during 48 h. Methods for simultaneous quantification of doxorubicin and doxorubicinol in urine, as well as total and unbound fraction in plasma were developed applying LC-MS/MS. Neither matrix effect or carryover effect were observed. The methods were linear for both analytes in the ranges of 0.4-200 ng/mL for total plasma concentration; 0.4-40 ng/mL for unbound fraction concentration in plasma and 20-8000 ng/mL urine. Doxorubicin pharmacokinetic parameters were calculated based on total plasma concentration versus time curves applying Phoenix® WinNonlin® software by tricompartmental model analysis. Distribution, fast elimination and slow elimination half-lives were observed to be 0.10, 2.55 and 40.87 h, respectively. Unbound fractions were 16.05% for doxorubicin and 17.34% for doxorubicinol. The fraction of doxorubicin dose recovered in urine (0-48 h) was 2.35% for the drug excreted unchanged and 1.35% for doxorubicinol. The clearance mean values for the assessed population were 58.07 L/h for total clearance, 1.45 L/h for renal clearance, 56.62 L/h for hepatic clearance and 0.71 L/h for doxorubicinol metabolite formation clearance. Thus, the data suggest that doxorubicin elimination is carried out mainly by biliary excretion. Initial total clearance values demonstrated 95.32% variation coefficient, while total clearance values corrected to weight or body surface area presented similar variation coefficients, respectively 88.74% and 89.84%. The detailed pharmacokinetics study of doxorubicin and its metabolite doxorubicinol made it possible to calculate, for the first time in humans, the hepatic extraction ratio (E = 0.63), categorising doxorubicin as an intermediate hepatic-extraction-ratio drug.

Le microenvironnement tumoral via les macromolécules matricielles est connu pour jouer un rôle clé dans la réponse des cellules cancéreuses à la chimiothérapie en favorisant leur survie et leur prolifération. L'impact du collagène de type I, protéine matricielle majeure du microenvironnement, a été évalué au niveau des capacités migratoires des cellules tumorales et de leur réponse aux agents anticancéreux, doxorubicine et metformine. Cette approche a étémenée chez des cellules humaines HT1080 hautement invasives au moyen de systèmes de culture par coating 2D ou en matrice 3D. Les effets de modifications post-traductionnelles du collagène comme la carbamylation et de la glycation ont été également étudiées. Les résultats montrent que le collagène 3D inhibe l'activité anti-migratoire de la doxorubicine. Cette protection met en jeuune préservation des niveaux d'activation de FAK et RhoA impliquées dans la formation des fibres de stress d'actine et des plaques d'adhésion focales. Le collagène glyqué 2D et dans une moindre mesure le carbamylé inhibent l'adhésion, la migration des cellules tumorales et désorganisent leur cytosquelette d'actine via des modifications de distribution de la vinculine, de FAK et des intégrines 1. Cet impact de la glycation a été aussi mis en évidence en matrice 3D après modification du processus de glycation. Enfin, la glycation exerce un effet protecteur vis-àvis des capacités anti-prolifératives et anti-migratoires de la doxorubicine et de la metformine. En conclusion, nous mettons en évidence une nouvelle forme de résistance CAM-DR dirigée contre l'activité anti-invasive de médicaments ; cet effet pouvant être généré par une protéine matricielle native ou modifiée lors de situations physiopathologiques associées au cancer. / The tumor microenvironment via the extracellular matrix plays an important role in cancer cell response to chemotherapy by promoting their survival and proliferation. In this work, we studied the impact of collagen type I, a major matrix protein of tumor microenvironment, on the migration capacities of tumor cells and on their response to anticancer drugs such as doxorubicin and metformin. This approach was performed with the highly invasive human cell line HT1080,by means of 2D coating or 3D matrix cell culture systems. The effects of collagen posttranslational modifications such as carbamylation and glycation were also assessed. The results show that the 3D collagen inhibits the anti-migratory effect of doxorubicin. This protection is carried out through the preservation of the activation states of FAK and RhoA, which are involved in the formation of actin stress fibers and focal adhesions. On 2D coating, the glycated collagen and at a lesser extent the carbamylated one decrease the adhesion, the migration oftumor cells and, disorganize the actin cytoskeleton via a modified distribution of vinculine, FAK and beta1 integrins. This impact is also demonstrated by using 3D matrices, after adaptation of the glycation process. In addition, we reported that the glycated collagen protects against the antiproliferative and the anti-migratory effects of doxorubicin and metformin. In conclusion, we highlighted a new form of CAM-DR resistance that targets the drugs anti-invasive activity. This impact could be induced by the native form of matrix proteins or the modified one found inpathological situations which are associated to cancer.

O gênero Streptomyces tem sido estudado nas últimas décadas, pela sua capacidade de produzir vários produtos naturais bioativos. Os microrganismos produtores de antibióticos exigem um ou mais mecanismos de resistência durante a produção destes. Streptomyces olindensis DAUFPE 5622 produz o antitumoral cosmomicina D que faz parte da família das antraciclinas. Neste estudo, se apresenta um modelo de resistência que é expresso conjuntamente com a biossíntese do antibiótico. Os três mecanismos incluem uma bomba de efluxo, um mecanismo enzimático envolvido na resposta a espécies reativas de oxigênio, e um mecanismo envolvido no reparo do DNA, pela ação da proteína homóloga UvrA. Os genes de resistência de S. olindensis foram clonados e expressos em S. albus, contendo o plasmídeo de expressão PEM4A com o promotor constitutivo ermE*p. Avaliou-se a capacidade de resistência à diferentes concentrações das antraciclinas cosmomicina D e doxorubicina. A expressão de cada um dos mecanismos de resistência incrementou a resposta às antraciclinas. / Streptomyces produce various bioactive natural products and possess resistance systems for these metabolites, which are co-regulated with antibiotic biosynthesis genes. Antibiotic producer microorganisms require one or more self-resistance determinants to survival during antibiotic production. Streptomyces olindensis DAUFPE 5622 produces the antitumoral Cosmomycin D, a member of the anthracycline family. In this study we show the resistance genes in Cosmomycin D biosynthetic cluster that provide self-resistance, including an ATP-dependent efflux pump, resistance to DNA damage through UvrA class IIa protein, and response to reactive oxygen species by the enzyme Glutathione peroxidase. We cloned and expressed the resistance genes from S. olindensis in <i.S. albus, containing the expression plasmid PEM4A with the constitutive promoter ermE*p. We evaluated the capacity of resistance to different concentrations of anthracyclines Cosmomycin D and the commercial Doxorubicin. The expression of each resistance component increment the response to anthracyclines.

O câncer é considerado uma das principais causas de morte no mundo. Para o tratamento dessa doença, frequentemente são utilizadas estratégias farmacológicas baseadas na intervenção quimioterápica, no qual a doxorubicina (DOX) é largamente utilizada. Visto que, o músculo esquelético possui importante papel na captação de glicose, o objetivo do presente trabalho foi investigar o efeito da DOX na intolerância à glicose. Para isso foram utilizados ratos Wistar, os quais receberam uma dose única de DOX ou salina intraperitoneal (15mg/kg). Avaliamos a expressão de proteínas envolvidas na sensibilidade à insulina e captação de glicose. Os ensaios captação de glicose foram realizados em cultura de miócitos, no qual foi utilizado o agonista de AMPK. O tratamento com DOX causou resistência à insulina e hiperglicemia. No músculo EDL e em miócitos houve menor expressão de GLUT-4 e de AMPk. Em conclusão, o tratamento com DOX causou intolerância à glicose e redução da expressão de AMPk e GLUT-4. A utilização do agonista de AMPk foi capaz de recuperar à intolerância à glicose. / The cancer is considered a major cause of death worldwide. For the treatment of this disease, with frequency are used pharmacological strategies based in chemotherapeutic intervention, in which doxorubicin (DOX) is widely used. Since the skeletal muscle plays an important role in glucose uptake, the aim of this study was to investigate the effect of DOX in glucose intolerance. For this Wistar rats which received a single dose of DOX or saline intraperitoneally (15mg / kg). We evaluated the expression of proteins involved in insulin sensitivity and glucose uptake. The glucose uptake assays were performed on culture myocytes, which was used in the agonist of AMPK. The treatment with DOX caused insulin resistance and hyperglycemia. In the EDL muscle myocytes and there was less expression of GLUT4 and AMPK. In conclusion, treatment with DOX caused impaired glucose tolerance and reduction of expression of AMPK and GLUT-4. The use of AMPK agonist was able to recover glucose intolerance.

O Sarcoma de Ewing (ES) é um raro tumor de ossos e tecidos moles com uma característica translocação cromossomal, a fusão EWS/FLI-1, que atua sobre diversos processos oncogênicos. O desenvolvimento da resistência à quimioterapia é comum no tumor e continua como uma das principais causas na falha do tratamento. O objetivo desse estudo foi avaliar a expressão de genes após a indução de resistência em linhagens celulares de ES. Foi selecionado um conjunto de genes (CCAR1, TUBA1A, POLDIP2, SMARCA4 e SMARCB1) a partir da mineração da literatura em resistência tumoral para duas drogas utilizadas na terapia de ES, doxorrubicina e vincristina. Descrevemos a expressão de cada gene selecionado antes e após as linhagens SK-ES-1 serem submetidas a um protocolo de indução de resistência para ambos os fármacos, que obteve êxito ao induzir as células à resistência. A expressão relativa dos níveis de mRNA foi avaliada e foi encontrada em maior expressão para os genes SMARCA4, SMARCB1 e POLDIP2, e em menor expressão para os genes TUBA1A e CCAR1, quando comparadas às linhagens de controle não-resistentes de cada quimioterápico. Os resultados sugerem o envolvimento de mecanismos de reparo de dano ao DNA, remodelamento de cromatina via SWI/SNF, atividade de microtúbulos e atividade spliceossomal nos processos de resistência quimioterápica em ES. / Ewing Sarcoma (ES) is a rare bone and soft tissue tumor with a characteristic chromosomal translocation, the fusion protein EWS/FLI-1, that drives several oncogenic processes. The development of resistance to chemotherapy is common and remains as the main cause of treatment failure. The goal of this study was to evaluate the expression of selected genes in ES cell lines after induction of resistance. A set of genes (CCAR1, TUBA1A, POLDIP2, SMARCA4 and SMARCB1) was data mined from tumoral resistance literature for two drugs used in ES therapy, doxorubicin and vincristine. We describe the expression of each selected gene before and after SK-ES-1 cell lines were exposed to a drug resistance inducing protocol for doxorubicin and vincristine. Cell lines were successfully induced to be resistant to doxorubicin and vincristine. The relative mRNA expression levels were upregulated for genes SMARCA4, SMARCB1 and POLDIP2 and downregulated for genes TUBA1A and CCAR1, when comparing resistant and non-resistant ES cell lines for each drug. The results suggest involvement of repair pathways, SWI/SNF chromatin remodeling, microtubule and spliceosomal activity processes in drug resistance mechanisms in ES.

A insuficiência cardíaca (IC) é o estágio final de diversas patologias cardíacas e apresenta alta morbimortalidade. Dentre as causas, estão os efeitos cardiotóxicos em pacientes tratados com doxorrubicina (Dox). A fisiopatologia da IC apresenta aumento da atividade barorreflexa e marcada hiperatividade simpática (HS), estado compensatório à redução do débito cardíaco. Porém, a HS prolongada culmina em alterações deletérias para o sistema cardiovascular (SC) com piora do quadro de sintomas. Atualmente muito se discute sobre o papel dos corpúsculos carotídeos (CC) na fisiopatologia da IC devido ao seu reflexo simpatotônico e a melhora de pacientes portadores de IC após a remoção dos CC. O nosso objetivo foi avaliar a influência do CC na evolução da IC induzida pela DOX. Para tal, 35 ratos Wistar machos foram dispostos em 4 grupos: controle Salina (CSAL; n=7) e Controle Dox (CDOX; n=12), Desnervado Salina (DSAL; n=4) e Desnervado Doxo (DDOX; n=12). A desnervação consistiu na ressecção do nervo sinusal bilateral prévia à administração de Dox; a indução da IC ocorreu através de 6 aplicações de Dox, na dose de 2.5mg/kg, pela via IP a cada 4 dias. Após 15 dias do término da indução, os animais foram avaliados pelo ecocardiograma e canulados para registro de pressão arterial invasiva e avaliação hemodinâmica, autonômica, barorreflexa e quimiorreflexa. A análise dos resultados mostra que o grupo CDOX apresentou redução do peso corporal, da sensibilidade baro e quimiorreflexa, hiperatividade simpática acompanhada de redução vagal, redução da morfologia cardíaca associada à disfunção diastólica e sistólica e redução do peso bruto cardíaco e ventricular. A desnervação não foi capaz de reverter os efeitos deletérios causados pela Dox, inclusive a desnervação acentuou a disfunção diastólica e sistólica induzida pela Dox. Concluiu-se que a desnervação carotídea não foi eficiente em melhorar a insuficiência cardíaca induzida pela Dox no modelo experimental proposto / Heart failure (HF) is the final stage of several cardiac pathologies and results in high morbimortality. Among the causes, we can mention the cardiotoxic effects in patients treated with doxorubicin (Dox). The pathophysiology of HF has increased baroreflex activity and marked sympathetic hyperactivity (HS), a compensatory state to the reduction of cardiac output. However, prolonged HS results in worsening of the symptoms. Currently, the role of carotid corpuscles (CC) in the pathophysiology of HF is discussed due improvement of sympathetic reflex presents in patients with HF after CC removal. The objective of this study was to evaluate the influence of CC on the evolution of HF induced by DOX for this method 35 Male Wistar rats arranged in 4 groups: Salina control (CSAL; n = 7) and Dox Control (CDOX; n = 12) Salina Denerved (DSAL; n = 4) and Dox Denerved (DDOX; n = 12). A denervation consisted of bilateral sinus nerve resection prior to Dox administration, induction of HF through 6 Dox applications at a dose of 2.5mg / kg, via IP every 4 days. After 15 days of the end of the induction, the animals were evaluated by echocardiogram and cannulated to record invasive blood pressure and hemodynamic, autonomic, baroreflex and chemorreflex evaluation. Our experiment demonstrated that the CDOX group had reduction of body weight, baro and chemoreflex sensitivity, sympathetic hyperactivity accompanied by vagal reduction, reduction of cardiac morphology associated with diastolic and systolic dysfunction and reduction of gross cardiac and ventricular weight. The denervation is not able to reverse the deleterious effects caused by Dox, including denervation accentuated by Dox-induced diastolic and systolic dysfunction. Based on our results on a carotid denervation it was not effective in improving heart failure induced by Dox

Em julho de 2008, a ANVISA publicou um informe técnico esclarecendo um item importante da RE nº 1 (2005), que trata sobre os estudos de estabilidade de medicamentos. Este documento originou uma nova RDC de nº 58, publicada em dezembro de 2013, a qual estabelece limites para produtos de degradação em medicamentos. O objetivo do presente trabalho foi avaliar o comportamento do antineoplástico cloridrato de doxorrubicina frente a condições de decomposição (hidrólise ácida, básica, oxidação, temperatura e fotólise), a fim de se determinar suas principais vias de degradação e também elucidar as estruturas de seus principais produtos de degradação. Para isso foi desenvolvido e validado um método indicativo de estabilidade por HPLC-DAD-MS, o qual utiliza como fase estacionária uma coluna Luna C18(2) (150 mm x 3,0 mm, µm) com gradiente de fase móvel de tampão formiato de amônio 5 mmoles.L-1 pH 3 e metanol e fluxo de 0,3 mL.min-1. Ao longo do estudo foram encontrados diversos produtos de degradação, dentre eles a 7- deoxidehidrodoxorrubicinona, originada por hidrólise ácida e também o produto da degradação térmica de m/z 530, o qual foi encontrado nas análises do medicamento após expirado seu prazo de validade. Além disso, a avaliação da toxicidade in vitro de amostras contendo produtos de degradação de origem térmica indicou atividade citotóxica para células mononucleares. / ANVISA has published in July 2008, a technical sheet expaining an important item of the RE No. 1 (2005), which describes drugs stability studies. This document originated a new RDC No. 58, published in December 2013, which sets thresholds for degradation products in pharmaceuticals. The aim of this study was to evaluate the behavior for the antineoplastic doxorubicin when exposed to stress conditions (acid and base hydrolysis, oxidaton, photolysis and temperature) in order to determine the major pathaways of degradation and also to elucidate the stuctures of their main degradation products. To this was developed and validated a target stability indicatinf method by HPLC-DAD-MS, with Luna C18 (2) (150 mm x 3.0 mm. 3 µm) column as stationary phase and a mobile phase gradient composed of ammonium formate buffer 5 mmoles.L-1 and pH 3 and metanol with flow of 0.3 ml min-1. Throughout the study many degradation products was discovered, among them 7- deoxydehydrodoxorubicinone, formed by acid hydrolysis and also the main product of termal decomposition of m/z 530, wich was found in the analyzes of the medicine after the expiry of its validity were found. Furthermore, evaluation of the in vitro toxicity of samples containing degradation products of thermal decomposition was found to be citotoxic for mononuclear cells.

Cancer cells that survive chemotherapy treatment often develop resistance to the administered chemotherapeutics, as well as to many other types of drugs, because the cancer cells increase their production of efflux pumps in the cell. This undesired phenomenon of resistance to cancer drugs is known as multidrug resistance. This work uses a novel drug carrier, called an eLiposome, to achieve cytosolic drug delivery to kill multidrug-resistant cancer cells. An eLiposome consists of a perfluoropentane (PFC5) emulsion droplet inside of a liposome. Folate attached to the eLiposome facilitates uptake into the cell. The PFC5 droplet is metastable at body temperature, but will rupture the liposome as the droplet expands during vaporization, and will release any drugs encapsulated inside of the liposome directly to the cell cytosol. Laser and ultrasound were examined as triggers to initiate the vaporization of the PFC5 droplet and actuate the release of doxorubicin (Dox) from folated eLiposomes containing Dox (feLD). Gold nanorods (GNRs) were synthesized and transferred to PFC5 droplets. Although GNRs are efficient at converting irradiated laser light to heat, no vaporization of the PFC5 droplets was observed when irradiated with laser light. Further investigation into the energy required for vaporization of PFC5 droplets revealed that there are currently no portable and wearable lasers available to provide enough energy to vaporize PFC5 droplets. Two seconds of ultrasound can release 78% of encapsulated Dox from feLD. Dox-sensitive KB-3-1 cells and Dox-resistant KB-V1 cells treated with feLD (without ultrasound) had cell viabilities of 33% and 60%, respectively. Ultrasound had negligible additional effect on the cell viability of KB-3-1 and KB-V1 cells treated with feLD (33% and 53%, respectively). We hypothesized that the Dox fiber formed during the loading of Dox into the eLiposome is a site for heterogeneous nucleation once the feLD is endocytosed by the cell, and vaporization and drug release occurs with or without ultrasound. Blocking the efflux pumps with verapamil decreases the rate at which Dox is exported from multidrug-resistant cells. When verapamil is co-delivered with feLD, the cell viability of KB-3-1 and KB-V1 cells decreases to 29% and 25%, respectively; thereby reversing the multidrug resistance possessed by KB-V1 cells. The delivery of doxorubicin inside of folated eLiposomes with an efflux pump blocker is a novel way to kill multidrug-resistant cancer cells as effectively as non-resistant cancer cells independent of lasers or ultrasound.

Cancer is responsible for about 25% of deaths in developed countries and for 15% of all deaths worldwide. Cancer is a devastating disease and while there have been great advances in the development of anticancer drugs, off-target toxicity is a major limitation with conventional cancer chemotherapy. The consequence of this form of treatment results in the killing of healthy and rapidly-growing non-cancerous cells including cells in the bone marrow; hair follicles; and cells in the mouth, digestive tract, and reproductive system. In addition to these general effects, certain anticancer drugs can have other associated toxicities. For instance, the anticancer drug doxorubicin (Dox), which my research has focused around, has dose-limiting cardiotoxicity. For these reasons, there has been much research focused on improving the selectivity of anticancer drugs in order to lower their toxicity to normal cells and decrease associated side effects. To circumvent the problem of non-selectivity, many methods have been developed to target cancer cells regionally at the site of the tumor. One such method is photodynamic therapy (PDT) which relies on a photosensitizer that is activated using light directed towards the tumor. Once activated, the photosensitizer creates singlet oxygen, which is cytotoxic to the illuminated tumor cells. PDT has shown profound effects in the treatment of many cancers including head and neck, lung, bladder, prostate, and esophagus. As PDT continues to be streamlined, it has the potential to serve as a standalone modality in the treatment and management of cancer at different stages. However, there are many inadequacies in the use of PDT. The fundamental problem lies in the inability of PDT to treat solid, bulky tumors or deep-seated tumors. This is partly due to the fact that current PS used cannot effectively kill cancer cells because with increasing tissue thickness the number of hypoxic cells increases. We have designed a new light based drug delivery which will allow for drugs to be released on the surface of the tumor, allowing the drug to freely diffuse through the tumor without the need of O2 and also, due to the manner our drug is attached, a more potent form the pre-attached drug is released. In this methodology, drug delivery will only be specific to an area of interest and the potential for side effects emerging from chemotherapy should be limited. Here we have shown, for the first time the generation of highly potent drug in a light dependent manner via a photocaging molecule and the commonly used chemotherapy agent Dox. We designed our photocage to generate a latent reactive form of Dox after illumination with UV light. This intermediate reacts in an intramolecular fashion to generate a highly potent form of the drug compared to its previous unattached form. Because of its high potency we have named the cleaved drug Super-Dox. Once the synthesis of the photocleavable drug conjugate was complete and we confirmed the photorelease of Super-Dox, via photolytic assay, and confirmed our drug conjugate is 80% cleaved from its photocage after 30 minutes of irritation with UV light. Next, we performed cell viability assays using MCF7 breast cancer cells to determine the efficiency of our drug conjugate to induce cell death. Our drug conjugate was able to induce significant cell death in the presence of light when compared to the dark. When compared to Dox, our cleaved drug conjugate is 26 folds more potent with light illumination an when compared to toxicity in the dark our drug conjugate was 374 fold less potent when conjugated to the photocage. However, our drug conjugate was not completely benign in the dark due to cell permeability, evidenced by confocal microscopy, we have worked equip our linker with sulfated cell impermeable group that will lower its background toxicity in the dark and allow us to achieve even higher enhancements in activity with light. This type of innovation creates a new avenue into cancer treatment which can limit adverse side effects and improve overall treatment.

<p>This thesis describes the design and synthesis of molecules with potential roles in biomedicine, with an emphasis on molecular recognition in complex biological environments. The first chapter describes the synthesis and evaluation of compounds for use in nuclide therapy. Carboranes are frequently used in the development of drugs for Boron Neutron Capture Therapy. New routes for monohydroxylation at the B and C atoms of <i>p</i>-carborane have been developed. The Suzuki-Miyaura reaction has been applied to the cross-coupling of <i>bis</i>(neopentyl glycolato)diboron or <i>bis</i>(pinacolato)diboron and 2-I-<i>p</i>-carborane. The synthesized derivatives are important intermediates in the synthesis of a number of potentially biologically active carborane-containing molecules.</p><p>The DNA intercalator doxorubicin has been functionalized to enable ¹²⁵I labelling. The aim of combining the DNA intercalator with ¹²⁵I was to achieve high delivery of cytotoxic radiation to the nucleus. The DNA-binding ability and cellular uptake of the synthesized compounds have been evaluated. One of the compounds bound strongly to DNA and had similar cellular uptake as daunorubicin, which makes the compound very interesting for further biological evaluation.</p><p>The second chapter describes the use of polypeptide conjugates to broaden our knowledge of molecular recognition. The polypeptides consist of 42 amino acids each and are designed to fold into helix-loop-helix motifs that dimerize due to their amphiphilic character. The polypeptides are combined with a variety of small organic molecules. The incorporation of small aromatic molecules to influence the structure and dynamics of a polypeptide has been investigated. By attaching a dansyl group to the side chain of a lysine residue, the dynamics of the protein’s hydrophobic core where affected to such a degree that a native-like fold was formed. The polypeptide conjugates have also been used to study the binding and recognition of native proteins. High-affinity binders for chitinases and acetylcholine esterase have been developed and evaluated.</p>