M.Sc. / Established therapies currently in use for the treatment of breast cancer are high risk, since their employment harbors multiple undesirable and detrimental side effects. In many cases these are associated with poor therapeutic outcome managing only to briefly extend patient lifespan. As a result, many newly designed treatments have surfaced that aim to effectively remove cancerous tissue and improve survival rates while minimizing the aggressive onsets to the patient. Photodynamic Therapy (PDT) has, for a long time, been targeted as a combatant for cancer. Its therapeutic mechanism is based on the tumor-specific intracellular localization of a photosynthetic compound, i.e: photosensitizer, prior to its irradiation-mediated excitation thereby generating high levels of reactive oxygen species (ROS). At the molecular level, this causes irreversible photodamage to vital intracellular targets resulting in cell death. The plasma membrane-, mitochondrial-, lysosomal-, and endoplasmic reticulum systems are all prime targets of PDT and vary in susceptibility depending on both the type of cancer being treated and the photosensitizer administered. Newly designed photosensitizers are governed by their enhanced structural properties to localize and therefore target certain areas of a cell. Since each cancer type has a unique set of susceptible and resistant characteristics, knowledge of each new photosensitizers’ range, efficiency, and mechanism of cell death is required. This enables pairing of these drugs to appropriate cancer types for maximal PDT effect. Here, two newly designed metallo-phthalocyanine photosensitizers, AlPcSmix and GePcSmix, were analyzed for their photodynamic effect on the estrogen-positive, breast cancer cell line, MCF-7. Being one of the most reliable cell lines, it is a prominent research model because it mimics the problems encountered with tumor resistance to therapy induced cell death via pathway restrictions. Photosensitizer administration and excitation by light irradiation to this cell culture system was therefore referred to as in vitro Photodynamic Treatment (in vitro PDT) and not Therapy. ii Initial dosage and time responsive studies confirmed that 35 μM AlPcSmix and 115 μM GePcSmix both excited using 15 J/cm2 at 680 nm proved most effective in reducing viability, whilst individually contributing little adverse influence to cellular homeostasis. Using these dosages, in vitro PDT analysis on several cellular parameters indicated a complex mode of cell death was induced. Morphology revealed typical markers consistent with apoptotic, autophagic and necrotic cell death while variations in proliferation and cytotoxicity levels were inconsistent with stress responses observed. This correlated with the detection for four common apoptotic markers which also revealed discrepancies within the death pathway as possible mutational deficiencies may have rendered MCF-7 cellular systems incomplete. Taken together, the wide range of cellular parameters studied suggests cells undergo a mixture of death modes interchanging via a complex system of molecular switches over time that concludes in secondary necrosis. This was attributed to the assortment of sulphonated phthalocyanine species enabling a broad intracellular distribution range coupled with the non-specific targeting action typical of the ROS generated, in addition to the absence of a phagocytic conclusion to the death process. In vitro PDT with AlPcSmix was shown to harbor a greater toxicity to GePcSmix as cells completed the death response within a shorter time period however, both promoted MCF-7 population cell death sufficient enough to warrant further study for their use as potential agents in the PDT of breast cancer.

M.Sc. / Breast cancer is the most commonly diagnosed cancer and cause of death in women world wide as well as in South Africa. Cancer is characterized by over-proliferation of cells or the inhibition of programmed cell death known as apoptosis, a well coordinated process that results in the activation of several proteases and other hydrolytic enzymes. Apoptosis is regulated by enhancers and inhibitors, such as heat shock proteins (Hsps) that modulate the apoptotic process according to the demands of specific cells. Hsps can regulate the release of pro-apoptotic factors from the mitochondria as well as inhibit key steps in the apoptotic cascade such as activation of caspases. The Hsp70 family constitutes the most conserved and best studied class of Hsps and the stress-induced Hsp70 also blocks the apoptotic pathway at different levels. Hsp70 is furthermore overexpressed in several tumor cells and can effectively inhibit cell death induced by a wide range of stimuli including several cancer related stresses such as hyperthermia, chemotherapeutic agents and nonsteroidal anti-inflammatory drugs (NSAIDs) i.a. aspirin (acetylated salicylic acid) In addition to their potent analgesic, antipyretic and anti-inflammatory activity, NSAIDs can inhibit cell proliferation and induce apoptosis in many cancer cell lines. However, NSAIDs can also lower the temperature threshold for Hsp70 induction and induce a transcriptionally inert intermediate of Hsp70 that can be converted to a transcriptionally active state by a subsequent exposure to heat shock. This suggests that NSAIDs act differently under heat stress, possibly increasing cellular protection through the heat shock response in cancer cells with already elevated levels of Hsps. It is therefore hypothesized that the synergistic use of heat shock with salicylic acid (SA) treatment will increase Hsp70 expression and protein accumulation and further enhance the resistance of breast cancer cells to apoptosis. The effects of SA on its own or in combination with HS on the viability of MCF-7 breast cancer cells as well as Hsp70 protein levels and gene expression were therefore investigated. SA treatments were found to induce cell death in a dose-dependent manner with the most significant decrease in viability observed after treatment with 20 mM SA.

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.

As breast cancer incidence and survival rates increase, there is an urgent need to make appropriate psychosocial support available to all women with breast cancer. In this qualitative study, narrative inquiry was used to examine how women with breast cancer used visual creative expression (art therapy and/or independent art making) to address psychosocial needs that arose for them after their diagnoses. Seventeen women, aged 37-82, participated in this investigation. Data analysis of in-depth interviews with these women focused on narratives they constructed about why they turned to art therapy and/or independent art making and how it helped to be involved in these activities. Particular attention was given to the issue of meaning making. Four storylines emerged from the analysis. "Art and art therapy as a haven" came from narratives about using art making or art therapy for comfort and affirmation. The narratives that comprised "getting a clearer view" were about using visual creative expression to create a clear picture of emotional experience. "Clearing the way emotionally" came from narratives about self-expression and about processing difficult emotions. The narratives that yielded "expanding and enlivening the self were about the women fortifying and energizing themselves through visual creative expression. Two minor themes related to the role of the art therapist and negative experiences with art therapy also emerged. In their narratives, the women portrayed visual creative expression as flexible, compelling, and powerful means of addressing multiple psychosocial needs simultaneously. Above all, the storylines show that the women valued visual creative expression as a way to reduce the feeling of threat to existence, to affirm present existence, and to promote the ongoing existence of both their psyches and their bodies. The results of this study contribute to the field of psycho-oncology by extending understandings of meaning making in relation to breast cancer, supplying detailed explanations from the perspectives of women with breast cancer of how visual creative expression can be helpful, and providing valuable insight into how psychosocial support services based on visual creative expression might meet needs of women with breast cancer that would not be met through other types of services. / Graduate and Postdoctoral Studies / Graduate

Thesis (MSc. (Biochemistry)) -- University of Limpopo, 2017 / The malignancy of cancer cells is responsible for the high death rate in patients diagnosed with metastatic cancers. Medicinal plants represent a reservoir of bioactive compounds that can be useful in the management of cancer. In this study, semi-purified extracts of Ricinus communis leaves were evaluated for their potential to serve as an anti-metastatic agent by using in vitro assays that tested their effects on a number of processes related to metastasis. The exhaustive extraction procedure was employed to generate the crude acetone extracts of R. communis leaves. The crude extracts were then subjected to solvent-solvent fractionation to yield six semi-purified extracts (n-butanol, Chloroform, Ethyl-acetate, n-hexane, Methanol + H2O and H2O). Thin layer chromatography (TLC) was done to determine the phytochemical composition of the semi-purified extracts as well as their antioxidant potential. Non-polar fractions showed to have a diverse mixture of phytochemicals with, however, very limited antioxidant activity. On the other hand, polar fractions showed to have phytochemical compounds with strong antioxidant potential. TLC guided the selection of n-hexane and n-butanol as fractions of great phytochemical diversity and antioxidant activity, respectively. The selected fractions were then assessed for their effect on the viability of normal fibroblasts (BUD-8) and breast (MCF-7) cancer cells using the MTT assay. The n-butanol fraction was shown to significantly decrease the viability of BUD-8 at concentrations above 200 µg/ml. The n-hexane fraction, however, showed to significantly affect the viability of the cells even at lower concentrations. On the positive side, the reduced viability of BUD-8 cells after exposure to both fractions was followed by an increase in cell proliferation after 24 hours suggesting that the extracts exhibited cytostatic rather than cytotoxic effects. Treatment of MCF-7 cells with different concentrations (100-500 µg/ml) of the fractions showed a dose- and time-dependant decrease in cell viability. Hoechst stain also confirmed the non-toxicity of the fractions to MCF-7 cells at 100 and 200 µg/ml. The fractions also showed to possess free radical scavenging activities by reducing the amount of intracellular ROS as demonstrated by the DCFH-DA fluorescent assay. Fluorescence intensity was strongly reduced in cells treated with the fractions and elevated in H2O2-treated and untreated MCF-7 cells. The effect of the fractions on metastasis was assessed by determining their effects on MCF-7 cell migration, attachment and invasiveness using wound healing assay, adhesion assay and Boyden chamber invasion assay, respectively. The wound healing assay showed the fractions to have strong inhibitory activities on the migration of MCF-7 cells. The xii ability of the cells to attach to cell culture treated plates was also greatly reduced in cells treated with the fractions. The n-butanol fraction was demonstrated to exhibit a time- and dose-dependent inhibition on MCF-7 cell invasion by reducing the cells’ capability to penetrate through the matrigel matrix to the bottom of the porous membrane. Gelatin-zymography was done to assess the effect of the n-butanol fraction on activity of MMP-2 and MMP-9. The fraction showed to completely inhibit the gelatinolytic activity of MMP-2 and no band corresponding to the molecular weight of MMP-9 was observed, suggesting that MCF-7 cells produce undetectable levels of MMP-9. The n-butanol fraction further showed to down-regulate the expression of a range of proteins such as MMP-9, uPA, VEGF, TGF-β1 implicated in metastasis and angiogenesis determined using the human angiogenesis antibody array kit. This study demonstrated that the fractions of R. communis extracts have the ability to inhibit major processes of the metastatic cascade by down-regulating the expression of proteins relevant to metastasis. Thus, the fractions can be considered as potential anti-metastatic agents functional in the regulation and/or treatment of malignant of cancers. / National Research Foundation (NRF)

Bakgrund: En av de mest förekommande sjukdomar hos kvinnor är bröstcancer. Bröstcancer uppstår genom cancer i bröstkörtel eller bröstkörtelgångarna. Behandling av bröstcancer innebär förändringar i vardagslivet. Kvinnor med bröstcancer lider av psykisk ohälsa där depression är vanligt. Sjuksköterskans roll är väsentlig för att upptäcka och förebygga ohälsa samt främja hälsa. Syfte: Syftet med studien var att belysa faktorer som är karaktäristiska för depression hos kvinnor under behandling för bröstcancer. Metod: En litteraturöversikt med deduktiv ansats valdes. Tolv kvantitativa artiklar sammanställdes efter litteratursökning och kvalitetsgranskning. Resultat: Fem kategorier av faktorer skapades: fysiska faktorer, psykiska faktorer, sociala faktorer, sociodemografiska faktorer och vårdrelaterade faktorer. Huvudfynd som framträdde var brist på socialt stöd, nedsatt sömnkvalitet och ökad oro samt ångest. Slutsats: Under behandling för bröstcancer finns det många faktorer som är karaktäristiska till depression. Dessa faktorer leder till nedsatt livskvalitet och många kan förebyggas genom omvårdnadsåtgärder. Förslag på omvårdnadsåtgärder är att sjuksköterskan ska bidra med socialt stöd, ge egenvårdsråd för förbättrad sömn och utveckla tillgängligheten för gruppterapi. Det anses finnas en vinst med att utföra screening för depression av alla patienter med bröstcancer för att effektivt identifiera och förebygga ohälsa hos denna patientgrupp.

Breast cancer affects over three million women in the United States, but this disease burden is not shared equally across all races. Black women, in particular, are diagnosed with more advanced cancer at a younger age and experience a disproportionately high mortality rate compared to white women. Factors that contribute to such disparity include socioeconomic status, tumor biology, age, insurance status, comorbidities, obesity, patients’ reproductive history and barriers to quality care. These factors alone, however, do not account for all the racial differences in mortality and outcomes experienced by black women. There is a growing body of literature that indicates black women are not receiving the same treatment and care as white women. Black women are less likely to receive surgery, radiation therapy, hormone therapy and targeted therapy than white women. Black women are also more likely to experience delays in the initiation of treatment, early discontinuation of treatment and overall guideline non-concordant care. The current literature has presented widespread racial disparities in the treatment of black women with breast cancer. Future research needs to focus on tangible interventions such as physician bias training and patient navigators to mitigate the inequity of care in the treatment of breast cancer.

IUPUI / Fatty acid synthase (FASN) over-expression has been associated with poor prognosis and recurrence in cancer patients. In addition, it has also been found that overexpression of FASN causes resistance to DNA-damaging treatments by up-regulating the non-homologous end joining (NHEJ) repair of DNA double-strand break. Proton pump inhibitors (PPIs), were originally designed to decrease gastric acid production by binding irreversibly with gastric hydrogen potassium ATPase. PPIs have recently been reported to reduce drug resistance in cancer cells when used in combination with other chemotherapeutics, although the mechanism of resistance reduction is uncertain. In our lab, previous investigation showed that PPIs decreased FASN thioesterase (TE) domain activity and cancer cell proliferation in a dose-dependent manner. In this study, I tested the hypothesis that PPIs sensitize breast cancer cells to doxorubicin and ionizing radiation (IR) treatments by inhibiting FASN. When administered to breast cancer cells as single-agent, lansoprazole exhibited the highest potency in inhibiting both FASN activity and breast cancer cell proliferation, among four PPIs tested. In addition, treatment of breast cancer cells with lansoprazole decreased the mRNA and protein levels of poly (ADP-ribose) polymerase-1 (PARP-1) and NHEJ activity, accompanied by elevated γ-H2AX expression. Following a 3-day treatment with lansoprazole, a dose-dependent disruption in cell cycle disruption and increased apoptosis were also detected. Combination of lansoprazole with either doxorubicin or IR caused profoundly higher levels of DNA damage accumulation than doxorubicin or IR treatment alone, suggesting synergistic effects. Taken together, our observations suggest that PPIs synergistically suppress breast cancer cells in combination with DNA damaging treatments by inhibiting FASN. These findings may provide a potential route to overcome resistance to DNA-damaging chemo/radiation treatments in refractory breast cancers.

Indiana University-Purdue University Indianapolis (IUPUI) / Breast cancer is the second most common cancer among women in the US after skin cancer. While early detection and improved therapy has led to an overall decline in breast cancer mortality, metastatic disease remains largely incurable, indicating a need for improved therapeutic options for patients. Telomeres are repetitive (TTAGGG)n DNA sequences found at the end of chromosomes that protect the ends from recombination, end to end fusions, and recognition as damaged DNA. The enzyme telomerase acts to stabilize short telomeres, preventing apoptosis or senescence due to genomic instability. Telomerase is active in 85-90% of cancers, and inactive in most normal cells, making telomerase an attractive target for cancer therapy. Use of the telomerase-specific, lipidated oligonucleotide GRN163L can antagonize telomerase activity and telomere maintenance in cancer cells by preventing telomerase from binding to telomeres. GRN163L has been shown by our laboratory to inhibit breast cancer cell growth and metastasis in animal models. However, the mechanisms of cancer cell growth and metastatic inhibition via GRN163L are not completely understood. The overall goal of this research project was to further elucidate the role of telomerase in breast cancer cell survival by: 1) determining the effects of combining telomere dysfunction induced by GRN163L with a DNA damage inducer (irradiation); 2) elucidating the mechanisms underlying the cellular response to GRN163L and the effect of combination therapy with the mitotic inhibitor paclitaxel; and 3) testing the hypothesis that a telomerase inhibitor can augment the effects of trastuzumab in breast cancer cells with HER2 amplification. Results support the central hypothesis that the telomere dysfunction, structural and proliferative changes in breast cancer cells induced by GRN163L can synergize with irradiation, paclitaxel, and trastuzumab to inhibit the tumorigenicity of breast cancer cells both in vitro and in vivo. Furthermore, GRN163L can restore sensitivity of therapeutically resistant breast cancer cells to trastuzumab. These results provide insight into the role of telomerase in cancer cell growth. Additionally, implications of this research support GRN163L as an important part of therapeutic regimens for primary tumors, recurrence, and metastatic disease.