It is always important to choose appropriate anticancer drugs for cancer patients. At RCL, a division of Uppsala university hospital, drug resistance profiles of patients are evaluated by a cell viability assay called FMCA. However, the number of anticancer drugs that can be evaluated by the FMCA is dependent on the number of viable cancer cells from tissues that can be obtained from each individual patient. Therefore, improvement of cell viability methods is an important issue at RCL. This study was performed to improve the FMCA method by organoid culture from colorectal cancer, renal cancer and osteosarcoma to increase the number of cancer cells. As results, it was successful to expand cryopreserved patient cancer cells to organoids to acquire more cells than before expansion. Organoids showed rounded structure in microscopy images. Thereafter, FMCA was performed on organoids as well as on thawed cryopreserved cancer cells from the original sample. Those results showed that original cancer cells, cryopreserved original cancer cells and expanded organoids derived from those cryopreserved cells had similar resistance profiles. It was also discovered that the organoids secreted VEGF under the cultivation. From those results, it can be concluded that organoids are representative of the original cancer from the patients. It is however needed to improve organoid culture methods, and to further confirm organoids by protein expression analysis and DNA analysis.

Since the discovery of anti-tumor activity of cisplatin in 1960, significant progress has been made in treating metastatic or advanced cancer with cisplatin and platinum compounds. Platinum compounds covalently bind to DNA and disrupt DNA function. They are also known to bind with amino acids like methionine, histidine and cysteine to form cisplatin-protein adducts which are responsible for most of its cytotoxicity and side effects. Recent articles on cisplatin-protein have shown that adding bulky adjuncts to cisplatin or using different platinum compounds varies the degree and extent of reaction thus possibly reducing cisplatin resistance and side effects. One of the proteins to study is cytochrome C, which is an intermediate in apoptosis (a controlled form of cell death used to kill cells in the process of development or in response to infection or DNA damage). Cytochrome C activates caspase 9, a cysteine protease, which in turn goes on to activate caspases 3 and 7, which are responsible for destroying the cell from within. In this study, we tried to examine how various platinum compounds like cis-Pt(NH3)2Cl2, cis-Pt(NH3)2(NO3)2, Pt(en)(NO3)2, Pt(Me4en)(NO3)2, Pt(NH3)2 (oxalate), Pt(en)(oxalate),Pt(Me4en)(oxalate), which have different ligands/bulk, react with cytochrome C in different physiological conditions. This research project subsequently focused on three main aspects: 1) to determine whether the concentration of platinum compounds made a difference in the reaction rate, 2) to determine whether the pH of the buffer shows any difference in the reaction rate, 3) to determine how the ligands coordinated to the platinum affected the rate. We used 1) HPLC with vitamin B12 (cyanocobalamin) as an internal standard. 2) Separate samples of platinum compounds with bovine serum albumin were then subjected to dialysis and were then sent to the Materials Characterization Center for analysis by ICP-AES spectroscopy. In summary, the following conclusions are stated: •The leaving group, pH, bulk and the concentration play a very vital role in determining the reaction rate for platinum-cytochrome C interactions. •Chlorides form excellent leaving groups followed by oxalates then nitrates. •Pt(en) reacts faster than Pt(NH3)2 which reacts faster than Pt(Me4en). •Nitrates, Pt(en) and few oxalate form multiple products showing non-specific binding. Only cis-Pt(NH3)2Cl2 and Pt(Me4en)(oxalate) formed predominately a single product showing target specific binding. •cis-Pt(NH3)2Cl2 showed an increased reaction rate at lower pH while cis-Pt(NH3)2(NO3)2 and Pt(Me4en)(NO3)2 showed higher reactions at higher pH. •Despite platinum compound was present in significant molar excess relative to cytochrome C, at the end of 21 hrs there was a significant amount of unreacted cytochrome C left except in case of cis-Pt(en)Cl2 which reacted with the whole cytochrome C in less than ten minutes. •We saw the rate of reaction in order of cis-Pt(en)Cl2 > Pt(en)(oxalate) > cis-Pt(NH3)2Cl2 > Pt(en)(NO3)2 > cis-Pt(NH3)2(NO3)2 > cis-Pt(NH3)2(oxalate) > Pt(Me4en)(oxalate) > Pt(Me4en)(NO3)2

Thermodynamic and kinetic analysis of the ligand substitution reactions of different heterometallic Ru(II)-Pt(II) complexes with a series of bio-relevant thiourea nucleophiles of different steric demands and ionic nucleophiles have been investigated as a function of concentration and temperature using UV/visible and stopped-flow spectrophotometric techniques. To achieve this, five different sets of complexes involving mono di and multinuclear homo and heterometallic complexes with tridentate N-donor ligands of different linker ligands were synthesized and characterized by various spectroscopic methods. The substitution reactions of the chloride complexes were studied in methanol in the presence of 0.02 M LiCf3SO3 adjusted with LiCl to prevent possible solvolysis. The aqua complexes were studied in acidic aqueous medium at pH 2.0. All reactions were investigated under pseudo first-order conditions. Density functional theory (DFT) calculations were used to aid further interpretations and understandings of the experimental results. Substitution reactivity of heterometallic Ru(II)-Pt(II) and Co(II)-Pt(II) complexes bridged by tetra-2-pyridyl-1,4-pyrazine (tppz) ligand was investigated for the first time. The reactions proceeded via two steps. The pseudo first-order rate constants, kobs(1st and 2nd) for the substitution of the chloride ligand(s) from the Pt(II) complexes and subsequent displacement of the linker. The dechelation step was confirmed by 1H NMR and 195Pt NMR studies. Incorporation of Ru(tppz) moiety increases the substitution reactivity and is ascribed to the increased π-back donation from the tppz ligand which increases the electrophilicity of the metal centre, overall charge and the global electrophilicity index of the complex. However, when changed the second metal centre from a Ru(II) to a Co(II), the rate of substitution decreased by a factor of four due to the weaker π- backbonding from Co(II). The substitution reactivity of another set of heterometallic Ru(II)-Pt(II) complexes with a semi-rigid linker, 4’-pyridyl-2,2’:6’,2”-terpyridine (qpy) showed that replacing the cis pyridyl group by a (tpy)Ru(qpy) moiety lowers the energy of anti-bonding LUMO (π*) orbitals and increases the metal-metal interactions and electronic transition within the complex whereby enhancing the reactivity of Pt(II) centre. However, when two Pt(II) moieties are linked to a (qpy)Ru(qpy), the orthogonal geometry at the Ru(II) metal centre prevents the extended π-electron density to flow through the three metal centres. The kinetic results obtained were supported by pKa and 195Pt NMR studies. Substitution reactions of the mononuclear Pt(II) complexes revealed that the polyethylene glycoxy pendent units act as a σ-donors including the lone pair electrons on the first oxygen atom thereby decreasing the reactivity of the parent Pt(II) terpyridine complex. However, this σ-donation towards the terpyridine moiety was found to be effective only up to one unit of the ethylene glycoxy pendant, beyond which the reactivity was sterically controlled. The dinuclear Pt(II) complexes bridged by polyehtyleneglycol ether units show that the reactivity of the complexes depend on the Pt···Pt distance and the steric hindrance at the Pt(II) centre. The substitution reactivity of heterometallic Ru(II)-Pt(II) complexes bridged by the same polyehtyleneglycol ether units indicate that the presence of Ru(tpy)2 moiety influences the structural geometry of the complex system which in turn controls the reactivity of the Pt(II) centre. This is further driven by the entrapment effect of the nucleophile due to the V-shape geometry adopted by the heterometallic complexes. In all cases the reactivity was also controlled by steric and electronic effects. However, when two metal centres are bridged by a flexible non-aromatic linker, the electronic transitions and the metal-metal interactions were found to be minor, especially for the longer linkers. The 1H and 195Pt NMR spectroscopic techniques were used to further understand the observed substitution kinetics and to confirm the degradation of the bridging ligand from the metal centre(s). In all cases, the negative activation entropies obtained support the associative mode of substitution This investigation reveals that the length and the nature of the bridging linker plays an important role in controlling the reactivity of the heterometallic complexes. It is envisaged that the findings of this project would offer a significant contribution to the pharmacological design of effective anticancer drugs. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.

The aldehyde dehydrogenase (ALDH) superfamily is gaining momentum in regard to stem cell and cancer research. However, their regulation and expression in the cancer microenvironment is poorly understood. The aim of this work was to understand the role of selected ALDH isoforms (1A1, 1A2, 1A3, 1B1, 2, 3A1 and 7A1) in colorectal cancer (CRC) and explore the impact of hypoxia on their expression. CRC cell lines (HT29, DLD-1, SW480 and HCT116) were grown under normoxic or hypoxic conditions (0.1% O2) and HT29 and DLD-1 in spinner flasks to generate multicellular spheroids (MCS). Hypoxia was demonstrated to have an impact on the ALDH expression, which appeared cell-specific. Notably, ALDH7A1 was induced upon exposure to hypoxia in both HT29 and DLD-1 cells, shown to be expressed in the hypoxic region of the MCS variants and in 5/5 CRC xenografts (HT29, DLD-1, HCT116, SW620, and COLO205). ALDH7A1 siRNA knockdown studies in DLD-1 cells resulted in significant reduction of viable cells and significant increase in ROS levels, suggesting ALDH7A1 to possess antioxidant properties. These findings were further supported using isogenic H1299/RFP and H1299/ALDH7A1 lung cancer cell lines. ALDH7A1, however, was found not to be involved in inhibiting the pharmacological effect or causing resistance to different cytotoxic and molecularly targeted anticancer drugs. To unravel the functional role of ALDH7A1, 9 compounds obtained from a virtual screening of 24,000 compounds from the Maybridge collection of compounds were used to probe ALDH7A1 functional activity. One compound, HAN00316, was found to inhibit the antioxidant properties of ALDH7A1 and thus could be a good starting point for further chemical tool development. Although this study underpins a potential important role of ALDH7A1 in hypoxic CRC, further work is required to fully validate its potential as a biomarker and/or pharmacological target.

Made available in DSpace on 2015-08-19T13:52:56Z (GMT). No. of bitstreams: 2 1.pdf: 1168426 bytes, checksum: a22061c806f5a4d1b7ff70ad14ba1834 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2013 / Fundação Oswaldo Cruz. Instituto de Tecnologia em Fármacos/Farmanguinhos. Rio de Janeiro, RJ, Brasil. / O câncer é um distúrbio celular marcado por alterações no processo de duplicaçãodo DNA, resultando em proliferação celular alterada, de forma desordenada.Qualquer que seja a causa do câncer este é basicamente uma doença celular caracterizada por um desvio dos mecanismos de controle das células. O câncer é um importante problema de saúde pública em países em desenvolvimento e desenvolvidos, sendo responsável por mais de seis milhões de mortes a cada ano, o que respresenta cerca de 12% de todas as causas de morte em todo o mundo.Embora as maiores taxas de incidência de câncer sejam encontradas em países desenvolvidos, dos dez milhões de casos novos anuais de câncer, cinco milhões e meio são diagnosticados nos países em desenvolvimento. No Brasil as estimativas apontam que em 2011 ocorreram 489.270 novos casos de câncer. Os tipos mais incidentes, à exceção do câncer de pele não melanoma, foram os cânceres de próstata e de pulmão no sexo masculino e os cânceres de mama e do colo do útero no sexo feminino. Neste cenário, este trabalho tem como objetivo fazer um levantamento geral dos gastos públicos com medicamentos antineoplásicos, a fim de se avaliar a necessidade de fabricação nacional por um laboratório oficial dos medicamentos em questão, visando a redução dos gastos públicos, ampliação da assistência farmacêutica, elucidação dos medicamentos estratégicos, evitando assim o desabastecimento e identificação dos principais fármacos/medicamentos para serem incorporados a produção pública. Após levantamento mercadológico e avaliação das necessidades do SUS, foram selecionados quatorze medicamentos antineoplásicos para produção nacional por um laboratório oficial, são eles: hidroxiuréia, capecitabina, citrato de tamoxifeno, acetato de megestrol, clorambucila, ciclofosfamida, tioguanina, mesilato de imatinibe, mercaptopurina, anastrozol, cloridrato de erlotinibe, bicalutamida, melfalana e metotrexato. Através de levantamento mercadológico e das necessidades do SUS no fornecimento de medicamentos antineoplásicos, sugere-se que a fabricação nacional por um laboratório oficial de tais medicamentos, poderia suprir as necessidades do SUS, evitando assim o desabastecimento do mercado público nacional de medicamentos antineoplásicos, garantindo o acesso de tais medicamentos à população, além da consolidação dessas classes terapêuticas nos laboratórios oficiais. / Cancer is a disorder characterized by cellular changes in the process of DNA replication, resulting in altered cell proliferation, in a disorderly way. Whatever the cause of this cancer cell is primarily a disease characterized by a deviation of the control mechanisms of cells. Cancer is a major public health problem in developed and developing countries, accounting for more than six million deaths each year, which respresents about 12% of all causes of death worldwide. Although the highest incidence rates of cancer were found in developed countries, the ten million new cases of cancer annually, five and a half million a re diagnosed in developing countries. In Brazil, estimates that in 2011occured 489,270 new cases of cancer. The most incidents, with the exception of nonmelanoma skin cancer, was prostate cancers and lung cancer in males and breast and cervical cancer in females. In this scenario, this paper aims to make a general survey of public spending with anticancer drugs, in order to evaluate the need for national manufacturing by an official laboratory of the drugs in question, in order to reduce public spending, expansion of pharmaceutical care, elucidation of strategic drugs, avoiding the shortage and identification of drugs for incorporation in public production. After marketing survey and needs assessment of SUS, fourteen anticancer drugs were selected for national production by an official laboratory, they are: hydroxyurea, capecitabine, tamoxifen citrate, megestrol acetate, chlorambucil, cyclophosphamide, thioguanine, imatinib mesylate, mercaptopurine, anastrozole, erlotinib hydrochloride, bicalutamide, melphalan and methotrexate. Through marketing survey, as well as a needs assessment of SUS in delivering anticancer drugs, suggests that the national manufacturing by an official laboratory of such drugs could supply the needs of SUS, avoiding the shortage of public market of anticancer drugs, ensuring access to such medicines to the population, and the consolidation of these therapeutic classes in official laboratories.

>Magister Scientiae - MSc / Genetic variability in genes encoding drug metabolizing enzymes, transporters and targets are known to be the main factors of inter-individual differences in therapeutic outcome. Genetic factors are estimated to be responsible for about 15-30% of inter-individual variation in drug disposition and response. Single-nucleotide polymorphisms (SNPs) are the most prevalent class of genetic variation that could explain the variability in drug efficacy and undesired side effects for patients. The aims of this study were to develop and evaluate the performance of robust and high throughput techniques for genotyping ten polymorphisms related to anticancer drugs and ten polymorphisms related to cholesterol lowering drugs. SNaPshot minisequencing and high resolution melt analysis (HRM) genotyping panels were developed, optimized, and their performances were evaluated and compared. SNaPshot minisequencing systems were developed and successfully optimized for the genotyping of ten SNPs associated with anticancer drug therapy, and ten SNPs associated with cholesterol lowering drugs. These systems were used to genotype the selected SNPs in 130 healthy Cape Admixed participants residing in Cape Town, South Africa. Population genetics data obtained for the studied SNPs were analysed using several statistical analysis software tools. Important population genetic parameters were calculated. Among others, allelic and genotypic frequencies were determined and compared with other populations in the world. High resolution melt analysis (HRM) genotyping panels were developed, optimized and their performance were evaluated and compared to the SNaPshot assays. HRM was explored as an alternative inexpensive and rapid methodology to genotype five SNPs related to anticancer therapy and five SNPs related to cholesterol lowering therapy (statins). Unlike the SNaPshot assays, rigorous optimization was required for the detection heterozygous genotypes via HRM. Both assays were validated using direct sequencing and compared to each other. The HRM system is a closed tube, cheap and (theoretically) rapid method for identifying genetic variations. HRM was however found to be more time consuming, needed further optimization, primer redesigning and more evaluation. The developed genotyping systems could be further validated using clinical samples from patients. This could help in optimizing drug therapy for cancer and cholesterol treatment.

Taxol (generic name paclitaxel), a plant‐derived antineoplastic agent, was originally isolated from the bark of the Pacific yew, Taxus brevifolia. Obtaining taxol from this source requires destruction of trees. It has been used alone or in combination with other chemotherapeutic agents for the treatment of breast, ovarian as well as many other types of cancer, including non‐small cell lung carcinoma, prostate, head and neck cancer, and lymphoma, as well as AIDSrelated Kaposi’s sarcoma. The mode of action of taxol against a number of human cancer cells is by preventing the depolymerization of tubulin during cell division. This molecule increases microtubule stability in the cell and induces apoptosis. From yew trees, the yield of taxol is usually between 0.004 to 0.1% of the dry weight. The commercial isolation of 1 Kg of taxol requires about 6 to 7 tons of T. brevifolia bark obtained from 2000‐3000 well‐grown trees. The limited supply of the drug has prompted efforts to find alternative sources of taxol. Alternative methods for taxol production, such as chemical synthesis, tissue and cell cultures of the Taxus species are expensive and give low yields. A fermentation process involving any microorganism would be the most desirable means to lower the cost and increase availability. The first report on the isolation of taxol‐producing fungi from Taxus brevifolia appeared in 1993 (Stierle, et al., 1993). Several taxol‐producing fungi have been identified since, such as Taxomyces andreanae, Taxodium disticum, Tubercularia sp., Pestalotiopsis microspora, Alternaria sp., Fusarium maire and Periconia sp (Li, et al., 1996, Strobel, et al., 1996a, Strobel, et al., 1996b, Li, et al., 1998b, Ji, et al., 2006, Xu, et al., 2006). This thesis investigates the isolation of an endophytic fungus, isolated from the stem cuttings of Taxus celebica, which produces taxol and related taxanes. We observed morphological and cultural characteristics and analyzed the sequences of rDNA ITS from the strain. The isolated fungus grew on potato carrot agar (PCA) medium at 25 °C and the colonies were white to off‐white, floccose, with irregular margins. The reverse side of the culture was cream in color. The morphology was examined microscopically following staining with cotton blue in lactophenol. Cultures produced macroconidia on slender, 85 μm long phialides. The macroconidia were 25‐40 X 3.75 μm. Cultures also produced round or oval microconidia. Analysis of the ITS and D1/D2 26S rDNA sequence revealed 99 % identity with Fusarium solani voucher NJM 0271. Based on its morphological, cultural characteristics and 26S rDNA sequence, the fungus was identified as F. solani. This fungus is different from the previously reported endophytic taxol‐producing species of Fusarium. Taxol and baccatin III, produced by this fungus, were identified by chromatographic and spectroscopic comparison with standard compounds. The amount of taxol produced by F. solani in potato dextrose liquid medium is low (1.6 μg l‐1) (Chakravarthi, et al., 2008). We further investigated different growth media and various factors of cultivation to select the medium and conditions that maximize production of taxol and other taxanes by this fungus. F. solani was grown in five well‐defined culture media under stationary and shake conditions separately for various time intervals and the amounts of taxol, baccatin III and other taxanes produced were estimated by competitive immunoassay. The modified flask basal medium (MFBM) was shown to yield the highest production of taxol (128 μg l‐1) which is 80 times more than when grown in potato dextrose liquid medium, baccatin III (136 μg l‐1) and total taxanes (350 μg l‐1) under shake conditions. From our results the highest taxol production of F. solani was achieved when cultured in MFBM. The production in MFBM was 80 times higher than that cultured in the potato dextrose liquid medium. In conclusion, it was shown that the culture medium plays a major role in taxol and other taxanes production and fungal growth. MFBM is the best medium, among the media studied, to produce taxol and other taxanes. The higher concentrations of NH4NO3, MgSO4, KH2PO4 and FeCl3 in the FBM medium seem important for production of taxol and other taxanes. These results can be considered as starting‐point for the research directed to improve taxol and baccatin III production by F. solani via different approaches including fermentations, strain improvement and genetic engineering techniques. Finally, in order to get more insights into the mode of action of this fungal taxol and baccatin III (for the first time), their apoptotic activity on different cancer cell lines was determined. We elucidated the biochemical pathways leading to apoptotic cell death after fungal taxol‐ and baccatin III‐ treatment in different cancer cell lines. Experiments are done on various cancer cell lines namely JR4 Jurkat (T‐cell leukemia), J16 Bcl‐2 Jurkat T cells, HepG2 (hepatoma), caspase‐8‐deficient Jurkat T cells, HeLa (human cervical carcinoma), Ovcar3 (human ovarian carcinoma) and T47D (human breast carcinoma) cells. We were able to demonstrate that both fungal taxol and baccatin III can induce apoptosis in all the cell lines tested, by flow cytometric analysis. Hallmarks of apoptosis following the signaling pathway to far more upstream‐located events were investigated using biochemical and cell biological methods. It has shown that during fungal taxol‐ and baccatin III‐induced apoptosis, DNA is degraded resulting in a increased number of hypodiploid cells reaching up to 65‐70% after 48 h. Disruption of mitochondrial membrane potential was examined by flow cytometric analysis using mitochondrial membrane potential sensitive dye JC‐1 and JR4‐Jurkat cells were shown to undergo significant loss of mitochondrial membrane potential loss of mitochondrial membrane potential reaching up to 70% in 6 nM fungal taxol and 65 % in 3.5 μM baccatin III after 36 h. These results were similar to those observed with standard taxol and baccatin III. We further investigated the role of caspases in fungal taxol‐ and baccatin III‐induced apoptosis, caspase‐8‐deficient Jurkat cells, Bcl‐2‐over‐expressed J16‐Jurkat cells and caspase inhibitors were used. Results derived from caspase‐8‐deficient Jurkat cells show that caspase‐8 is not involved in fungal taxol‐ and baccatin IIIinduced apoptosis of Jurkat cells. Using the pan‐caspase inhibitor (Z‐VAD‐FMK), caspase‐9 inhibitor (Z‐LEHD‐FMK), caspase‐3‐inhibitor (Z‐DEVD‐FMK), caspase‐2‐ inhibitor (Z‐VDVAD‐FMK) and caspase 10‐inhibitor (Z‐AEVD‐FMK), it was shown that caspase‐10 is involved in fungal taxol‐ and baccatin III‐ induced apoptosis in JR4‐Jurkat cells. It was also shown that inhibitors of caspases‐9, ‐2 or ‐3 partially inhibited fungal taxol‐ and baccatin III‐ induced apoptosis, whereas the caspase‐ 10 inhibitor totally abrogated this process. With the use of a fluorescence microscope, several morphological features characteristic of apoptosis such as condensed chromatin and apoptotic bodies were identified in fungal taxol‐ and baccatin III‐treated JR4‐Jurkat and HeLa cells. DNA fragmentations were shown by agarose gel electrophoresis method. Our work showed that treatment of JR4‐ Jurkat and HepG2 cells with fungal taxol and baccatin III induces apoptosis as shown by DNA ladder formation. Herein it was demonstrated that fungal taxol and baccatin III have a similar mechanism of action, but the efficacy of fungal taxol to induce apoptosis is higher. In summary, fungal baccatin III is found to be effective in inducing apoptosis similar to taxol but at higher concentration and both fungal taxol and baccatin III induce apoptosis via caspase‐10 and mitochondrial pathway in Jurkat cells. In conclusion, the present study describes isolation of a taxol‐producing endophyte F. solani IISc.CJB‐1. The growth requirements of this fungus for production of taxol, baccatin III and other taxanes were studied. The apoptotic activity of taxol and baccatin III (for the first time) was observed. In addition, our results show that the culture medium plays a major role in taxol and other taxanes production and fungal growth. Among the media studied, modified flask basal medium (MFBM) is the best to produce taxol and other taxanes. It is evident from this data that this fungal strain can be promising candidate for large‐scale production of taxol and related taxanes.

Currently available anticancer therapies are inadequate and spur demand for improved technologies. Among others, the utilization of nanocarriers for anticancer drug delivery has shown great potential in cancer treatment. Nanocarriers can improve the therapeutic efficiency of the drugs with minimization of the undesirable side effects. To evaluate potential application of this technology, two forms of nanocarriers have been studied: multi-walled carbon nanotubes (MWCNTs) and apoferritin. The aim of this study was to determine, whether given cytostatics (ellipticine, etoposide and doxorubicin) are bound to these nanotransporters and how are they released from them, especially depending on pH. Since the pH of the tumor cells is lower than the pH of healthy cells it would be preferred that the drugs would release from nanocarriers at the lower pH while at the physiological pH the release of the drug would be eliminated. The results found show that ellipticine is actually released from its MWCNT- and apoferrtin-encapsulated form at acidic pH (5.0), while at pH 7.4 its interaction with nanocarriers is stable. Ellipticine released from MWCNT is activated by microsomal enzymes to reactive metabolites (13- hydroxyellipticine and 12-hydroxyellipticine) forming DNA adducts. The results indicate that both...

Four known small molecule uracil-DNA glycosylase (UNG) inhibitors were synthesized and tested against human melanoma cells, IgR3 and MM200. They were found to be effective against cell proliferation at micromolar concentrations and to operate through a nonapoptotic mechanism. Thus, small molecules that target UNG may be useful as potential chemotherapeutic agents against human melanoma.

Cabozantinib is an anticancer drug that inhibit tyrosine kinases which allow signal pathways important for growth and development of tumors. It is used for treatment of medullary thyroid cancer, hepatocellular carcinoma and kidney cancer. The major enzymes of the first phase of biotransformation that metabolize cabozantinib are cytochromes P450. In this thesis it was studied metabolism of cabozantinib and cytochromes P450 that participated on this metabolism. Hepatic microsomes of rat, mouse and rabbit were used for studying metabolism of cabozantinib in this thesis. It was also focused on the impact of particular isoforms of cytochromes P450 on metabolism of cabozantinib in rat microsomes. Time dependence of cabozantinib conversion in hepatic rat microsomes was also studied. Enzyme kinetics of metabolism of cabozantinib in hepatic rat microsomes, as well as impact of cytochromes P450 inhibitors on the metabolism were included. Metabolites were analyzed by high performance liquid chromatography (HPLC) and mass spectrometry. Formation of metabolites of cabozantinib increased over time to 30 minutes of incubation and with some others to 40 minutes of incubation. Up to five different metabolites were detected in experiments (M1, desmethyl cabozantinib, M3, monohydroxy cabozantinib and cabozantinib...