Orientador: Sérgio Luis Felisbino / Coorientador: Elenice Deffune / Banca: Sylvia Stuchi Maria-Engler / Banca: Rosana Rossi-Ferreira / Banca: Patrícia Pintor dos Reis / Banca: Wagner José Favaro / Banca: José Andrés Yunes / Banca: José Roberto Bosqueiro / Banca: José Carlos Souza Trindade Filho / Resumo: O câncer de próstata (CaP) é importante causa de morte no mundo. Além do óbvio impacto na vida pessoal do paciente e na sua família, no Brasil esta doença gera custos altíssimos para o Sistema Único de Saúde (SUS), desde o diagnóstico até o óbito. As terapias disponíveis, além de causarem complicações e efeitos colaterais indesejáveis, não proporcionam sobrevida alta ao paciente. Além disso, os casos de cura são restritos aos diagnosticados precocemente, e com intervenção rápida, antes que o tumor se torne resistente à castração química. Neste sentido, estratégias preventivas são desejáveis para a diminuição da incidência e óbitos e, dentre elas, o uso da finasterida, um fármaco inibitório da enzima 5-α-redutase, foi proposto como potencial agente quimiopreventivo após estudo conduzido pelo Prostate Cancer Prevention Trial, que demonstrou significante diminuição na incidência de CaP no grupo de pacientes tratados, em comparação ao grupo controle. No entanto, mesmo com resultados promissores, foi detectado aumento, também significante, do número de casos de cânceres mais agressivos (alto grau) no grupo de pacientes que recebeu finasterida, em comparação aos pacientes do grupo controle. Após intenso debate entre urologistas, biologistas e cancerologistas, ainda não há consenso sobre a natureza artefatual ou de real indução de cânceres mais agressivos pela finasterida. O órgão regulatório americano Food and Drugs Administration (FDA) declarou que o aumento dos casos agressivos pela finasterida não deve ser negligenciado, e recentemente proibiu o uso deste fármaco como quimiopreventivo para o CaP. Uma vez que casos agressivos de câncer estão comumente relacionados à superexpressão de enzimas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Prostate cancer (PCa) is an important death cause in Brazil and other countries. Besides the obvious impact at patient's life, and their relatives, this disease consumes exorbitant resources from the Sistema Único de Saúde (SUS), from diagnosis to death. The available therapies not only cause undesirable complications and side effects, but also are inefficient at providing good survival expectancies for those affected. Moreover, the cure is only possible when the tumors are readily found and when the intervention is fast enough to prevent that the tumor become castration-resistant. In this sense, preventive strategies are desirable in order to lower incidence and death, and amongst them, finasteride (Fin) treatment, an inhibitor of the 5-alpha reductase enzyme, was proposed as a potential chemopreventive agent after the study conducted by the Prostate Cancer Prevention Trial reported a significant lower incidence of PCa cases on Fin-treated patients, when compared to control patients. However, even though these results were promising, this study also reported a significant increase on more aggressive, high-grade PCa, amongst Fin-treated patients, compared to those not exposed to Fin. After an intense debate about factual or artifactual Fin-induced high-grade PCa cases, between urologists, biologists and oncologists, there are still no decisive conclusions on this matter. The regulatory USA organ, Food and Drugs Administration (FDA), has recently declared that the higher incidence of a more serious form of PCa at the Fin-treated patients must not be neglected, and prohibited its use as a chemopreventive agent. Given that the aggressive cancer cases are commonly associated with the super-expression of matrix metalloproteinases (MMPs) enzymes, with consequently higher invasion and migration potential of tumor... (Complete abstract click electronic access below) / Doutor

Bakgrund: Cytostatikabehandling används vid många cancerdiagnoser och kan ge omfattande biverkningar då hela kroppen påverkas. Lukt- och smakförändringar är ett problem i samband med behandling och beskrivs ha en koppling till bland annat påverkad aptit och försämrad livskvalitet. Syfte: Syftet med denna litteraturstudie var att identifiera de eventuella lukt- och smakförändringar som kan uppstå i samband med cytostatikabehandling samt undersöka på vilka sätt individens aptit kan påverkas till följd av detta. Vidare syftade studien till att undersöka hur utbrett detta problem är. Metod: Forskningsdesignen var en deskriptiv litteraturstudie. Genom databaserna PubMed och Cinahl valdes 13 kvantitativa originalartiklar ut för att sedan kvalitetsgranskas. En resultatanalys genomfördes och därefter sammanställdes en syntes. Resultat: Hos majoriteten av individer med cancersjukdom förekom lukt- och smakförändringar under cytostatikabehandling. Det resulterade i sin tur i en negativ påverkan på aptiten med konsekvenser såsom ofrivillig viktnedgång och försämrad livskvalitet. De vanligaste luktförändringarna som identifierades var ökad känslighet mot bland annat matlagningslukt och kroppslukter. Gällande smakförändringar påverkades grundsmakerna sött, salt, surt och beskt, varav flest individer upplevde förändringar i sött och salt. Dock var det surt och beskt som genererade mest negativa konsekvenser för individen. Fler kvinnor än män var utsatta för dessa aptitrelaterade problem. Slutsats: Studien fann att lukt- och smakförändringar var ett utbrett problem hos individer under cytostatikabehandling. Påverkan på den olfaktoriska respektive gustatoriska funktionen innebar för många en nedsatt aptit med följder som exempelvis förändrade matpreferenser, svårigheter i det sociala livet samt ofrivillig viktnedgång vilket ledde till en ökad morbiditet och försämrad livskvalitet.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Oral mucositis (OM) induced by antineoplasic drugs is an important, dose-limiting, and costly side effect of cancer therapy. Calotropis procera is a plant plant constitutively produces abundant latex that is reported to possess anti-inflammatory, bacteriolytic, insecticidal, analgesic properties. The present work aimed to describe the effect of laticifer proteins of Calotropis procera (LP) in the expression of pro-inflammatory cytokines and inducible enzymes, such as, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the model of OM in Hamsters. OM was induced by two intraperitoneal (i.p.) administrations of 5-Fluorouracil (5-FU) on the 1st and 2nd days (60 and 40 mg/kg, respectively) in hamsters (n=5). LP (0,25; 1; 5 E 25 mg / kg) was injected i.p. 24h before and 24h after mechanical trauma of the cheek pouches. Control group received only saline. On the 10th day, the animals were sacrificed and tissues from the cheek pouches were harvested. Macroscopical and histopathological (inflammatory cell infiltration, edema, hemorrhage and the formation of ulcerations and abscess) analysis as well as immunohistochemistry for TNF-&#61537;, IL-1&#946;, iNOS and COX-2 was performed in the cheek pouch tissue. Kruskal Wallis/Dunn was used as statistical tests. P<0.05 was accepted. Ethics Committee 036/10. The LP significantly inhibited macroscopical and histopathological parameters when compared to control group with maximum effect in macroscopic scores reaching 75% and 66% of maximum effect at the histopathological evaluation. The MPO activity was also significantly inhibited by LP in 91% at the same dose (p<0,001) and also inhibited the lost weight of 5- FU induced-oral mucositis. The cheek pouches of hamsters submitted to OM showed marked immunostaining for TNF-&#61537;, IL-1&#946;, iNOS and COX-2 on inflamed conjunctive (Cj) and epithelial (Ep) tissue compared with the cheek pouches of the normal control group. LP caused considerable reduction in the immunostaining for TNF-&#61537; (62%,Cj; 70%,Ep), IL-1&#946; (87%,Cj; 80%,Ep), iNOS (82%Cj; 52%Ep) and COX-2 (70%,Cj; 100%,Ep) in the check pouches tissue when compared with the group of animals subjected to experimental mucositis that received saline instead of LP. These findings show anti-inflammatory effects of LP in 5-FU-induced OM. The protective effect could be supported by the reduction of the expression of pro-inflammatory cytokines, such as TNF-&#61537; and IL-1&#946; and the enzymes iNOS and COX-2. The protective mechanism appears to involve inhibition of the expression of iNOS, COX-2, TNF-&#61537;, and IL- 1&#946;. / Mucosite oral (MO) induzida por drogas antineoplÃsicas à um importante fator limitante da dose e efeitos colaterais da terapia do cÃncer. Calotropis procera à uma planta que produz lÃtex constitutivamente abundante que à relatado possuir propriedades antiinflamatÃrias, bactericidas, inseticidas, analgÃsicas. O presente trabalho teve como objetivo descrever o efeito das proteÃnas do lÃtex da Calotropis procera (LP) na expressÃo de citocinas prÃ-inflamatÃrias (TNF-&#945; e IL-1&#61538;) e enzimas induzÃveis, como, ciclooxigenase-2 (COX-2) e Ãxido nÃtrico sintase induzÃvel (NOSi) no modelo de MO em hamsters. A mucosite oral foi induzida por duas administraÃÃes intraperitoneal (i.p) de 5-fluorouracil (5-FU) no 1  e 2 dias nas doses de 60 e 40 mg/kg, respectivamente nos animais (n = 5). As LP (0,25; 1; 5 E 25 mg/kg) foi injetado via i.p. 24h antes e 24h apÃs o trauma mecÃnico da mucosa jugal. O grupo controle recebeu apenas soluÃÃo salina. No 10 dia, os animais foram sacrificados e os tecidos da mucosa jugal foram colhidos. Foram realizadas no tecido mucosa jugal as anÃlises macroscÃpicas e histopatolÃgicas (infiltraÃÃo de cÃlulas inflamatÃrias, edema, hemorragia e à formaÃÃo de ulceraÃÃes e abscessos), bem como a imunohistoquÃmica para TNF-&#945;, IL-1&#946;, NOSi e COX-2. Foram utilizados Kruskal Wallis / Dunn como testes estatÃsticos, onde P <0,05 foi aceito. O estudo foi submetido ao Comità de Ãtica sob o protocolo 036/10. Observou-se que a LP inibiu significativamente parÃmetros macroscÃpicos e histopatolÃgicos, quando comparado ao grupo controle, com efeito mÃximo nos escores macroscÃpicos atingindo 75% e 66% do efeito mÃximo na avaliaÃÃo histopatolÃgica. A atividade de Mieloperoxidase (MPO) tambÃm foi significativamente inibida por LP em 91% com a mesma dose (p <0,001) quando comparado ao grupo controle e tambÃm inibiu a perda de peso em animais submetidos a mucosite oral e tratados com LP. A mucosa jugal dos animais submetidos a MO mostrou imunomarcaÃÃo para TNF-&#945;, IL-1&#946;, NOSi e COX-2 na conjuntiva inflamada (Cj) e tecido epitelial (Ep) em comparaÃÃo com o tecido jugal do grupo normal. LP causou reduÃÃo considerÃvel na imunomarcaÃÃo para TNF-&#945; (62%, Cj, 70%, Ep), IL-1&#946; (87%, Cj, 80%, Ep), NOSi (82% Cj; Ep 52%) e COX -2 (70%, Cj, 100%, Ep) no tecido jugal quando comparado com o grupo de animais submetidos à mucosite experimental que receberam salina, em vez de LP. Esses achados demonstram efeitos anti-inflamatÃrios de LP em MO induzida por 5-FU. O efeito protetor poderia ser suportado pela reduÃÃo da expressÃo das citocinas prÃ-inflamatÃrias, como TNF-&#945; e IL-1&#946; e na expressÃo de enzimas COX-2 e NOSi. O mecanismo de proteÃÃo parece envolver a expressÃo inibitÃria da NOSi, COX-2, TNF-&#945; e IL-1&#946;.

Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Submitted in fulfillment of the requirements of the Degree of Master's in Biotechnology, Durban University of Technology, 2017. / Nanotechnology is explained as the science of engineered materials and systems on a molecular scale. This innovation is currently used in a wide variety of applications which include using these nanoparticles as drug delivery vehicles. Such nanocarriers are relatively smaller than 100 nm in size with the ability to convey therapeutic drugs to a number of disease sites. Platinum-based nanoparticles have been extensively used in a number of applications namely catalysts, gas sensors, glucose sensors and cancer therapy. The properties of platinum nanoparticles (PtNP’s) typically depend on characteristics such as shape, particle size, elemental composition and structure, all of which can be manipulated and controlled in the fabrication process. Their unique size in the nanometer scale makes platinum nanoparticles an ideal candidate as targeted drug delivery vehicles. To target an anticancer drug to a diseased site is a distinctive feature of most studies, which aim to transfer an adequate dosage of the drug to cancer cells. Transport systems used as carriers of anticancer drugs offer numerous advantages, which include improved efficacy and a decrease in toxicity towards healthy cells when compared to standard drugs. The aim of this study was to determine the effect of platinum nanoparticles, gemcitabine and gemcitabine conjugated platinum nanoparticles (Hybrids) against cancer cells and healthy cells and to determine the mode of cell death and cell death pathways using flow cytometry. Platinum nanoparticles were synthesized via the reduction of hexachloroplatinic acid using sodium borohydride in the presence of capping agents. Synthesized platinum nanoparticles and the hybrids were characterized by observing peaks at 301 nm and 379 nm respectively using UV-visible spectroscopy. TEM images revealed that the PtNP’s and the conjugate compounds were spherical in shape with core sizes of 1.14 nm - 1.65 nm and 1.53 - 2.66 nm respectively. The bioactivity platinum nanoparticles, gemcitabine and the hybrids were investigated using MCF7 and Melanoma cancer cells at different concentrations from 0.10 to 100 µg/ml. Results indicated that conjugated nanoparticles induced the highest cell inhibition against both cell lines compared to gemcitabine and platinum nanoparticles. Bioactivity against PBMC (peripheral blood mononuclear) cells indicated that all three compounds show little or no effect towards the healthy cell line compared to the control. Melanoma cell line was used to determine the mode of cell death. Apoptosis was detected using Annexin V-FITC to detect membrane changes, JC-1 to detect a loss in mitochondrial membrane potential and caspase-3 assay kits. Results indicated that a significant amount of cell death was caused by cleavage of caspase-3. Nanoparticle drug delivery is an area that has shown significant promise in cancer treatment. Interaction of nanoparticles with human cells is an interesting topic for understanding toxicity and developing potential drug candidates. Imagine, something that is atleast or more than 80,000 times smaller than the edge of the ridge on a fingertip and unlocks a new wilderness into cancer research. Nanotechnology, known as the science of minute, is changing the approach to cancer and especially future diagnosis and treatment. Nanotechnology permits scientists to fabricate new apparatuses that are definitely smaller than cells, giving them the chance to attack tumor diseased cells. This innovation not just empowers practitioners to recognize malignancies prior but additionally holds the guarantee of halting cancer growth before it further develops. This progressive approach is so exact, specialists will in future be able to outline a unique treatment for an individual’s own restorative and hereditary profile. Researchers are designing nanoparticles that detect and destroy diseased cells and this optimistic innovation could be personalized for targeted drug delivery, enhanced imaging and ongoing affirmation of cancer cell death. The National Cancer Institute remains hopeful that facilitated development, nanotechnology will drastically change cancer treatment. / M

M.Tech. (Radiography) / Cervical cancer is the most frequently diagnosed cancer among women in Zambia. More recently, improved cure rates have been obtained with the concomitant use of radiotherapy and chemotherapy in locally advanced cancer of the cervix. However, the side effects associated with the treatment have a major impact on the quality of life (QoL) of these women. Prior to this study, QoL in Zambian women treated for cervical cancer with chemo-radiation had not been assessed thus creating a gap in the literature and hampering an attempt to improve QoL in this cohort of patients. The aim of this study was therefore to evaluate the impact of chemo-radiation treatment on QoL and to determine what socioeconomic and demographic factors are closely related with QoL decrements in Zambian women treated for cervical cancer at Cancer Diseases Hospital. This would then facilitate the introduction of intervention programmes aimed at improving QoL in these patients. The study was prospective and explored the phenomenon of QoL with the use of the European Organization for Research and Treatment of Cancer (EORTC) questionnaire and a demographics questionnaire answered by 45 women treated for cervical cancer with chemo-radiotherapy at Cancer Diseases Hospital. The use of the EORTC quality of life questionnaire added validity and reliability to the study as it is used extensively to measure health-related quality of life in cancer survivors worldwide. Analysis of the data indicates that patients with advanced cervical cancer treated with chemo-radiotherapy generally experienced a favourable QoL, and treatment was considered worthwhile by the majority of patients. However, women described problems with sexuality and marital relationships. Low education and living without a partner were depicted as risk factors for the development of the reported problems. To improve QoL in survivors, interventions focusing on more social support, education to improve patients’ understanding of their disease and treatment effects as well as physical rehabilitation through exercise interventions are recommended as mandatory.

M.Tech. (Radiography) / This was a prospective, quantitative comparative study. The aim of the study was to evaluate acute toxicity of radical combination therapy, in the form of radiotherapy and chemotherapy, in HIV +ve patients on HAART and HIV -ve patients for cervical cancer at CDH, Lusaka, Zambia. The specific objectives were to compare acute toxicity in HIV +ve on HAART and HIV -ve patients and to assess the level of severity in the levels of toxicity. The study was conducted from January 2010 to December 2010. A hundred and twenty stage IB₂-IIIB cervical cancer patients were serially recruited and assigned study numbers for identification and confidentiality. Participants received Cisplatin based radical chemoradiation for five to six weeks during which time they were assessed for acute reactions and data was prospectively collected. Four systems namely Genitourinary, Haematopoietic, Skin, and Gastrointestinal were used for the assessment of toxicity in the study. Toxicity was scored using the NCI CTC v2.0. The results of this study showed that, major acute reactions in the CDH study participants were grade 3 leucopoenia (five in each study arm) and one grade 3 acute skin toxicity in the HIV +ve arm. Results also revealed that there were three HIV +ve study participants with grade 3 vomiting and one HIV –ve. There was one grade 3 anaemia in the HIV +ve arm, one grade 3 anaemia in the HIV –ve arm and one grade 4 anaemia in the HIV +ve arm. However, only the incidence of grade 3 leucopoenia in both study arms and vomiting in the HIV +ve study participants was significantly higher. This study demonstrated that radical chemoradiation is well tolerated by HIV +ve patients with intact immunity. Toxicity was usually mild and reversible and no exaggerated toxicities beyond those generally associated with single-agent Cisplatin were observed in the HIV +ve study participants. Therefore, radical chemoradiation in conventional doses can safely be given to cervical cancer HIV +ve patients who are on HAART.

Breast cancer is a leading cause of cancer death in Africa. Hsp90 has been identified as a target for anti-cancer treatments as its inhibition results in the disruption and ubiquitin–proteasome degradation of activated oncoproteins. Currently, there are no US Food and Drug Administration approved Hsp90 inhibitor drugs and existing Hsp90 inhibitors such as geldanamycin and novobiocin are hepatotoxic and display a low affinity for Hsp90, respectively. Therefore, there is a need for the development of Hsp90 inhibitors with improved inhibitory properties. In this study twelve natural compounds bearing a quinone nucleus were screened and characterised for the modulation of Hsp90. The compounds analysed formed three series; the sargaquinoic acid (SQA), naphthoquinone, and pyrroloiminoquinone alkaloid series. Certain compounds exhibited half maximal inhibitory concentrations of between 3.32 μM and 12.4 μM, while others showed no antiproliferative activity at concentrations of up to 500 μM in the MDA-MB-231 breast adenocarcinoma cell line. Immunofluorescence and Western analyses indicated that the modulation of Hsp90 and partner proteins by SQA was more similar to that of novobiocin. Isothermal titration calorimetry analyses suggested that SQA interacted with Hsp90β with a low affinity, and saturation-transfer difference nuclear magnetic resonance confirmed that this interaction with Hsp90β occurred through the methyl moiety bound to 1, 4 benzoquinone of SQA. Pulldown assays indicated SQA disrupted the association between Hsp90 and Hop dose-dependently, more similarly to novobiocin. Immunofluorescence and Western analyses performed on naphthoquinone and pyrroloiminoquinone alkaloid compounds indicated modulation of Hsp90 and Hsp90 partner proteins by the compounds. Naphthoquinone compounds were prioritised for analysis for binding to Hsp90β over the pyrroloiminoquinone alkaloid compounds. Lapachol interacted with Hsp90β with a low affinity however; this interaction was thought to be too weak to disrupt the association of Hsp90 and Hop. The remaining naphthoquinone compounds showed no interaction with Hsp90β, thus allowing the determination of a preliminary structure-activity relationship for these compounds. To the best of our knowledge, this is the first study to describe a systematic subcellular analysis of the effects of geldanamycin and novobiocin in comparison to sargaquinoic acid and compounds of the naphthoquinone and pyrroloquinoline scaffold on Hsp90 and its partner proteins. / Microsoft� Word 2010 / Adobe Acrobat 9.54 Paper Capture Plug-in

Breast cancer, the most common malignancy diagnosed in women, is one of the leading causes of death in women worldwide. In South Africa only 32% of women diagnosed with advanced breast cancer survive more than five years. The search for new chemotherapeutic agents capable of effectively treating breast cancer is therefore essential. Recent evidence supporting the cancer stem cell theory of cancer development for breast cancer challenges the current theories of cancer development and hence treatment. Cancer stem cells are a small subpopulation of tumour cells that possess properties of both cancer cells and stem cells and are believed to be the tumour-initiating population of many cancers. Cancer stem cells are inherently resistant to many chemotherapeutic agents and in this way have been associated with repopulation of tumours after chemotherapy. This phenomenon is proposed as a possible mechanism for cancer relapse after treatment. Cancer stem cells have also been implicated in metastasis, the major cause of mortality in cancer patients. Therefore, any treatment that is capable of targeting and removing breast cancer stem cells may have the theoretical potential to effectively treat breast cancer. However, there are currently no such treatments available for clinical use. We were provided access to a library of novel indigenous small molecules isolated from red and brown algae found off the Eastern Cape of South Africa. The aim of this project was to analyse the anti-cancer and anti-cancer stem cell properties of the compounds in this library and to identify „hit‟ compounds which could form the basis for future development into new anti-cancer drugs. Ten novel compounds of algal origin were tested for cytotoxicity, by determining their ability to inhibit the growth of MCF12A breast epithelial cells and MCF7 breast cancer cells using the colorimetric MTT [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cell proliferation assay. All but one of the compounds tested exhibited cytotoxicity towards the MCF7 cancer cell line, with IC50 values (the concentration of the compound that leads to a 50% inhibition in cell growth) of between 3 μM and 90 μM. The chemotherapeutic drug paclitaxel was used as a positive control. Four of the compounds (RUMB-001, RUMB-002, RUMB-007 and RUMB-010/saragaquinoic acid) were significantly more toxic to the MCF7 cancer cell line, than the „normal‟ MCF12A breast cells and were selected as priority compounds for further analyses. In addition, two other compounds were selected as priority compounds, one highly cytotoxic towards both MCF12A and MCF7 cell lines (RUMB-015) and one which was non toxic to either cell line (RUMB-017/018). Preliminary studies into the mechanism of cytotoxicity using Western blot analysis for poly (ADP-ribose) polymerase (PARP) cleavage and Hoechst 33342 immunostaining in MCF-7 cells were largely unsuccessful. The Hoechst 33342 immunostaining assay did provide tentative evidence that selected priority compounds were capable of inducing apoptosis, although these assays will need to be repeated using a less subjective assay to confirm the results. The priority compounds were subsequently investigated for their cytotoxic effect on the cancer stem cell-enriched side population in MCF7 cells. The ability of the priority compounds to selectively target the cancer stem cell containing side population was assessed using two complementary flow cytometry-based techniques – namely the Hoechst 33342-exclusion assay, and fluorescent immunostaining for the expression of the putative cancer stem cell marker, ABCG2+. The ABCG2+ staining assay was a novel technique developed during the course of this study. It remains to be fully validated, but it may provide a new and reliable way to identify and analyse cancer stem cell containing side population cells. The MCF7 cells were treated with the compounds and the proportion of putative cancer stem cells compared with the size of the population in untreated cells was assessed. Three compounds (RUMB-010, RUMB-015 and RUMB-017/018) capable of reducing the proportion of side population cells within the MCF7 cell line were identified. Taking these data together, we identified two potential „hit‟ compounds which should be prioritised for future research. These are compounds RUMB-010/sargaquinoic acid and RUMB-017/018. RUMB-010 is of interest as it was shown to target the putative cancer stem cell population, in addition to the bulk MCF7 tumour line, but was relatively less toxic to the „normal‟ MCF12A cell line. RUMB-017/018 is of interest due to the ability to selectively target the cancer stem cell enriched side population, while having little effect on the normal (MCF12A) or bulk tumour (MCF7) cell lines tested. These compounds will be important as „hit‟ compounds for drug development and as tool compounds to study cancer and cancer stem cell biology.

Thesis (M.Sc. (Biochemistry)) -- University of Limpopo, 2020 / Despite major advancements in the development of various chemotherapuetic agents, treatment for lung cancer remains costly, ineffective, toxic to neighbouring normal noncancerous cells and still hampered by high level of remissions (Wistuba et al., 2018; Tana et al., 2016; Schiller et al., 2002). Synthesis of novel quinoxalines with a wide spectrum of biological activities has recently received considerable attention with promising anticancer drug activity since most of them do not affect non-cancerous cells and are derived from readily available less costly raw materials (Srivastava et al., 2014). Since combination treatment has been shown to augment and improve single drug treatment, trace elements were employed in this study in combination with quinoxalines derivatives (Gomez et al., 2016; Kocdor et al., 2015; Ku et al., 2012; John et al., 2010; Killile and Killilea, 2007). Zinc is an essential element that is integral to many proteins and transcription factors which regulate key cellular functions such as the response to oxidative stress, DNA replication, DNA damage repair, cell cycle progression, and apoptosis (Dhawan and Chadha, 2010). Owing to the importance of these two approaches, the aim of this study was to provide in vitro preliminary anticancer activity data on A549 lung cancer cells using combination of zinc and quinoxaline derivatives. An assessment of the quinoxaline derivatives ferric reducing power and DPPH free radical scavenging activity was performed. The cytotoxic and anti-proliferation activity of these derivatives and zinc on cancer cell lines was determined using the MTT assay. The ability of the quinoxaline derivatives and zinc to modulate oxidative stress was evaluated using the H2DCFDA fluorescence assay. Cell cycle arrest stages were analysed by flow cytometry through propidium iodide cell cycle analyses. The ability of the quinoxaline derivatives to induce apoptosis in cancer cells was assessed using DAPI/PI, Acridine Orange/Ethidium Bromide (AO/EB) and Annexin V-FITC/Dead Cell assays. Western blot was used to investigate the Bcl/Bax expression ratios in A549 lung cancer cells after treatment with quinoxaline derivatives, zinc and in combination. Of the four quinoxaline derivatives tested, 3-(quinoxaline-3-yl) prop-2-ynyl methanosulphate (LA-39B) and 3-(quinoxaline-3-yl) prop-2-yn-1-ol (LA-55) produced significant anticancer properties against A549 lung cancer cells at minimal concentrations of 25μM. Both quinoxaline derivatives displayed antioxidant properties and did not induce cell death in non-cancerous Raw 267.4 macrophage cells. Cytotoxicity was observed in A549 lung cancer, HeLa cervical cancer and MCF-7 breast cancer cells albeit inhibition was more pronounced in A549 lung cancer cells. Treatment of cancer cells with zinc also resulted in pronounced cytotoxicity at a minimal concentration of 25μM. Although reduced oxidative stress was observed in Raw 264.7 macrophages, in A549 lung cancer cells both compounds were able to increase ROS production which was accompanied by high levels of apoptosis when treated with derivatives and zinc alone but when in combination an improved higher level of apoptosis is observed. The improved anti-cancer activity of this drug combination treatment was further accompanied by lower Bcl/Bax expression ratios with upregulation of Bax in A549 lung cancer cells. The results of the study suggest that 3-(quinoxaline-3-yl) prop-2-ynyl methanosulphate and 3-(quinoxaline-3-yl) prop- 2-yn-1-ol are potential candidates drug for treatment of lung cancer. The use of these quinoxaline derivatives in combination with zinc can offer alternative treatment options for lung cancer. / National Research Foundation (NRF)