Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Introduction: Cancer is an emerging health problem in South Africa, with breast cancer being one of the leading cancers affecting women globally. Therefore, there is a need to find novel targets to improve the therapeutic options for these patients. A recently proposed target is the mitogen-activated protein kinase phosphatase-1 (MKP-1). Studies have suggested that mitogen-activated protein kinase phosphatases are involved in the development of cancer and play an important role in the response of cancer cells to chemotherapy. Additionally, numerous studies have indicated that there is increased expression of MKP-1 in breast cancers where its over-expression is proposed to be a significant mediator in chemo-resistance. We propose that inhibition of MKP-1 will increase the cytotoxic effect of doxorubicin in breast cancer cells, thus making the cells more responsive to treatment leading to increased cell death through autophagy and apoptosis. Methods: In MDA-MB231 cells, MKP-1 was inhibited using sanguinarine or MKP-1 siRNA and this was compared to a known inducer of MKP-1, dexamethasone. MDA-MB231 cells were treated with doxorubicin alone or in combination with MKP-1 inhibitors or an inducer. Following treatment, cell death was determined by trypan blue and a caspase glo assay as well as with western blotting. Autophagy was determined by western blotting and flow cytometry. LC3 and p62 were used as markers of autophagy and caspase 3 and PARP as apoptosis markers. Likewise, the level of MKP-1 expression under conditions of MKP-1 induction, inhibition or silencing was evaluated by means of western blotting. C57BL6 tumour bearing mice was used to analyse apoptosis and autophagy in vivo under conditions of MKP-1 inhibition, using sanguinarine, together with doxorubicin treatment. Western blotting was used to determine levels of caspase 3, LC3, p62 and MKP-1 expression. Results and discussion: A concentration and time curve indicated that 5 μM doxorubicin reduced cell viability in the MDA-MB231 cells significantly after 24 hours of treatment. MKP-1 expression was significantly reduced with sanguinarine and MKP-1 siRNA. Furthermore, our results indicate a significant increase in apoptosis in MDA-MB231 cells when treated with doxorubicin, under conditions of MKP-1 inhibition or MKP-1 silencing. Also, an increase in autophagic activity was observed following treatment with doxorubicin in combination with sanguinarine. Whole excised tumours of C57BL6 mice also showed an increase in apoptosis and autophagy following treatment with sanguinarine in combination with doxorubicin. This indicates that the inhibition of MKP-1 with sanguinarine sensitized the MDA-MB231 cells and E0771 cell tumours to doxorubicin-induced-apoptosis through a mechanism involving autophagy. Conclusion: This is an encouraging finding that could hopefully be used in future studies to overcome doxorubicin-resistance in breast cancer cells overexpressing MKP-1. Targeting MKP-1 can have potential therapeutic benefits for breast cancer patients by making chemotherapy more effective. Sanguinarine thus has potential to be developed as a clinically relevant inhibitor of MKP-1 which could provide a novel avenue for therapeutic intervention in combination with chemotherapy in breast cancer patients. / AFRIKAANSE OPSOMMING: Inleiding: Kanker is 'n vinnig groeiende gesondheidsprobleem in Suid-Afrika, met borskanker as een van die vernaamste kankers wat vroue wêreldwyd raak. Daar is dus 'n behoefte aan nuwe terapeutiese opsies vir hierdie pasiënte en mitogeen-geaktiveerde proteïenkinase fosfatase-1 (MKP-1) is onlangs voorgestel as ‘n moontlike teiken. Verskeie studies toon dat mitogeen-geaktiveerde proteïenkinase fosfatases betrokke is by die ontwikkeling van kanker en ook belangrike rolspelers is in die reaksie van kanker op chemoterapie. Daarbenewens toon talle studies dat daar verhoogde MKP-1 uitdrukking in borskanker is, asook dat dit ‘n belangrike bemiddelaar is vir die weerstand wat borskanker teen chemoterapie bied. Ons het dus voorgestel dat die inhibisie van MKP-1 die sitotoksiese effek van doxorubicin op borskanker selle sal verhoog; sodoende sal die kanker selle beter reageer op behandeling en dit sal dus lei tot verhoogde seldood deur autofagie en apoptose. Metodes: MKP-1 is geïnhibeer met behulp van sanguinarine of MKP-1 siRNA in MDA-MB231 selle en dit is vergelyk met 'n bekende MKP-1 induseerder, dexamethasone. MDA-MB231 selle is met doxorubicin alleen behandel of in kombinasie met MKP-1 inhibeerders of ‘n induseerder. Seldood is bepaal deur middel van ‘n trypan blou en kaspase toetsingsmetode, asook met die westelike kladtegniek. Autofagie is bepaal deur westelike kladtegniek en vloeisitometrie. LC3 en p62 is gebruik as merkers van autofagie en kaspase 3 en PARP is as apoptose merkers gebruik. MKP-1 uitdrukking is geëvalueer deur middel van westelike kladtegniek. C57BL6 muise met kankeragtige gewasse is gebruik om apoptose en autofagie in vivo te ondersoek. MKP-1 is geïnhibeer met sanguinarine en die muise is behandel met ‘n kombinasie van sanguinarine en doxorubicin. Kaspase 3, LC3, p62 en MKP-1 uitdrukking is bepaal deur middel van die westelike kladtegniek. Resultate en bespreking: ‘n Konsentrasie en tyd kurwe het aangedui dat 5 μM doxorubicin die MDA-MB231 selle se lewensvatbaarheid aansienlik verminder het na 24 uur. MKP-1 uitdrukking is ook aansienlik verminder met sanguinarine en MKP-1 siRNA. Verder dui die resultate op 'n beduidende toename in apoptose in MDA-MB231 selle na behandeling met doxorubicin onder toestande van MKP-1 inhibisie. 'n Toename in autofagiese aktiwiteit is waargeneem na behandeling met doxorubicin en sanguinarine. Die kankeragtige gewasse van die C57BL6 muise toon ook 'n toename in apoptose en autofagie na behandeling met sanguinarine en doxorubicin. Hierdie resultate dui daarop dat die inhibisie van MKP-1 met sanguinarine die MDA-MB231 selle en E0771 sel gewasse gesensitiseer het tot doxorubicin-geïnduseerde apoptose deur middel van ‘n meganisme wat autofagie insluit. Gevolgtrekking: Hierdie bevinding kan hopelik in toekomstige studies gebruik word om doxorubicin weerstand te oorkom in borskanker selle waar MKP-1 verhoog is. Deur MKP-1 te teiken, kan dit lei tot potensiële terapeutiese voordele vir borskanker pasiënte en sodoende kan dit chemoterapie meer effektief maak. Sanguinarine het dus die potensiaal om ontwikkel te word as ‘n klinies relevante inhibeerder van MKP-1 wat sodoende kan dien as terapeutiese intervensie in kombinasie met chemoterapie vir borskanker pasiënte.

BACKGROUND. Breast cancer is the most common type of cancer in women in the UK and is often treated with chemotherapy. Psychosocial side effects (anxiety, depression and fatigue) and cognitive side effects (memory and concentration difficulties) are frequently reported by breast cancer patients. Following recent advances in screening and treatment technology for the disease, survivorship rates have increased. Therefore, women are able to continue or resume their daily tasks during and following treatment. The impact of chemotherapy-related psychological side effects on quality of life and work ability are documented, however the impact on safety outcomes has currently been overlooked in this patient population. Evidence from other research fields suggests that anxiety, depression, fatigue and cognitive difficulties are associated with increased risk of accidents and injuries. OBJECTIVES. This research provides longitudinal self-report data on psychosocial well-being, cognitive function, quality of life, work ability and accident frequency outcomes. METHOD. A mixed-methods, prospective, longitudinal approach was employed. Breast cancer patients about to undergo chemotherapy treatment (n = 60) completed questionnaires at pre-treatment baseline, and again four months (follow-up time 1), eight months (follow-up time 2), and twelve months (follow-up time 3) later. A treatment control group of breast cancer patients receiving radiotherapy (n = 56), and an age-matched healthy control group (n = 58) were assessed at comparable intervals. In addition, a subsample of participants from the chemotherapy group (n = 11), radiotherapy group (n = 6), and healthy control group (n = 15) kept personal solicited diaries for a four-month period to capture the lived experience of managing daily tasks. The diary data were examined using thematic analysis. The combination of the quantitative and qualitative approaches added breadth and depth to the study with the aim of obtaining a realistic and comprehensive understanding of the impact of chemotherapy for breast cancer on patients daily lives. RESULTS. Chemotherapy patients reported a subtle decline in psychosocial well-being, cognitive function and quality of life, and encountered more accidents, particularly at mid-chemotherapy. CONCLUSION. It is important that healthcare professionals, breast cancer patients, relatives and employers are aware of the temporal fluctuations associated with chemotherapy-related side effects, particularly potential safety outcomes. Interventions could be developed to help patients manage their daily tasks in the home and in the workplace safely.

published_or_final_version / abstract / Medicine / Master / Doctor of Medicine

published_or_final_version / abstract / Surgery / Doctoral / Doctor of Philosophy

published_or_final_version / Surgery / Master / Master of Philosophy

The use of metallo-pharmaceuticals, such as the platinum drugs, for cancer treatment illustrates the utility of metal complexes as therapeutic agents. Platinum group metal complexes therefore offer potential as anti-tumour agents to fight cancer. This study was aimed at synthesizing and evaluating the effects of palladium(II) and platinum(II) complexes as anticancer agents.

Vaults, recently discovered in 1986, are multi-subunit organelles with a molecular mass of ,--,13 MDa. The specific function of vaults is unknown, although they are believed to be involved in internal transport. These ribonucleoproteins are composed of the major vault protein, which comprises ' 70% of the vault's mass, two minor proteins, TEP1 and vPARP, and untranslated RNA(s). It is believed that the protein components of the vault are structural while the RNAs are the functional components. Implications of the vault's involvement in multi-drug resistance in cancer have been made. In some resistant cancer cells, the major vault protein and vRNA(s) are up-regulated up to 15 times when cells are exposed to a cytotoxic drug. Cytotoxic drugs such as doxorubicin are administered as a cancer treatment, but may be ineffective because the drug is actively pumped out of the cell. Multi-drug resistance is the most common failure of chemotherapeutic cancer treatment. In order to prevent the development of multi-drug resistance this research employed the use of small interfering RNA technology to down-regulate the expression of one of the vault RNAs, vRNA3, in cultured GLC4 cells, a small-cell lung cancer cell line. If the vRNA(s) are the functional portion of the vault and a cloned siRNA prevents their up-regulation after drug exposure, the cells should lose their multi-drug resistance, stimulating apoptosis. If successful, this approach may provide an alternative approach to cancer treatment in cells which respond to chemotherapy by increasing the number of vault particles.Initially, the transfection of a plasmid into GLC4 cells was optimized. The best transfection efficiency (N20%) was obtained by using GeneTherapySystems' GenePORTER2 transfection reagent in serum free conditions. To determine if the vault RNAs are the functional portion of the vault complex that confers multi-drug resistance to a cell, a small interfering RNA fragment was designed to specifically knock-down the expression of human vault RNA 3. The siRNA sequence homologous to a portion of vault RNA3 was cloned into an expression vector, and using optimized transfection protocols was transfected into GLC4/REV cells. A Western analysis using caspase-8 antibodies showed no difference in caspase-8 expression in doxorubicin treated and untreated cells. Preliminary results yielded by reverse transcriptase polymerase chain reaction amplification of isolated RNA indicated that the vRNAs were not down-regulated by the siRNAs. / Department of Biology

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / Department of Chemistry

Investigations concerning the cellular response of tumor tissue to treatment with dimethyl sulfoxide and hematoxylin have not been reported. To establish the response of neoplastic tissue and cells to this combination of agents, this study was undertaken to determine the effects of dimethyl sulfoxide and hematoxylin on a transplantable lymphosarcoma in mice.

Colon cancer, a disease in which malignant tumors form in the tissues of colon, is the first commonest cancer and the second leading cause of cancer-related deaths in Hong Kong. The standard treatment options for colon cancer include surgery and chemotherapy. However, multidrug resistance (MDR) develops in nearly all patients with colon cancer. In fact, most of the cancer-related deaths are due to chemotherapy failure caused by MDR, which occurs during the course of cancer progression and chemotherapy. Thus, the reversal of MDR plays an important role in the successful chemotherapy for colon cancer. This study investigated such a pharmacological action in reversing MDR in colon cancer cells by tanshinones, targeting the two common mechanisms responsible for MDR, i.e. overexpression of ATP-binding cassette (ABC) transporters and suppression of apoptosis. / Overexpression of P-glycoprotein (P-gp), one of the most important ABC transporters, can mediate the efflux of drugs out of cancer cells, leading to MDR and chemotherapy failure. The reversal of P-gp-mediated MDR by five tanshinones including tanshinone I, tanshinone IIA, cryptotanshinone, dihydrotanshinone and miltirone was evaluated in colon cancer cells. Bi-directional transport assay showed that only cryptotanshinone and dihydrotanshinone decreased the P-gp-mediated digoxin efflux in Caco-2 cells. The two tanshinones potentiated the cytotoxicities of doxorubicin and irinotecan in P-gp overexpressing colon cancer SW620 Ad300 cells. Moreover, these two tanshinones also increased intracellular accumulation of P-gp substrate in SW620 Ad300 cells, presumably by down-regulating P-gp mRNA and protein levels, as well as inhibiting P-gp ATPase activity. / Suppression of apoptosis can lead to MDR in cancer cells to anticancer agents with pro-apoptotic property. Hence, this study also investigated the circumvention of resistance to apoptosis in drug resistant colon cancer cells by cryptotanshinone and dihydrotanshinone, two potential MDR-reversing tanshinones. The drug resistant SW620 Ad300 cells were still sensitive to both cryptotanshinone and dihydrotanshinone in the promotion of cell death. When compared with the parental SW620 cells, the two tanshinones induced less apoptosis but more autophagy in the drug resistant cells. Further studies showed that cell viability was increased after inhibition of autophagy by siRNA interference or autophagy inhibitor. Thus, autophagy induced by the two tanshinones was pro-cell death in SW620 Ad300 cells, which could overcome resistance to apoptosis. / In addition, suppression of apoptosis can be caused by p53 defects/mutations, which were found in more than 50% of all human cancers. Our results also showed that apoptosis and autophagy induced by cryptotanshinone and dihydrotanshinone were independent of the status of p53 in colon cancer cells. The p53-independent cytotoxic actions of the two tanshinones could be useful in overcoming resistance to apoptosis in cancer cells caused by p53 defects/mutations. / Taken together, the current findings indicate a great potential of cryptotanshinone and dihydrotanshinone in the reversal of MDR caused by P-gp overexpression and suppression of apoptosis. They are promising candidates to be further developed as therapeutic agents in the adjuvant therapy for colon cancer, especially for the multidrug resistant cancer types. / 結腸癌是指形成在結腸組織的惡性腫瘤，在香港常見的癌症中排第一位，亦是香港排第二位的致死癌症。結腸癌的標準治療方案主要包括手術和化療。然而，多藥耐藥是結腸癌成功化療的一個障礙。事實上，大多數癌症引起的死亡都和在癌症的發展和化療的過程中產生的多藥耐藥有關。因此，多藥耐藥的逆轉對於結腸癌的成功化療非常重要。本研究旨在通過針對多藥耐藥兩種常見的機制ABC跨膜蛋白的過表達和抑制的細胞凋亡來探討丹參酮對結腸癌細胞多藥耐藥的逆轉。 / P-gp的過表達可介導藥物排出癌細胞，從而導致多藥耐藥和化療失敗。本研究評價了tanshinone I，tanshinone IIA，cryptotanshinone，dihydrotanshinone和miltirone對P-gp介導的結腸癌細胞多藥耐藥的逆轉。雙向轉運實驗表明，只有cryptotanshinone和dihydrotanshinone可以減少P-gp介導的digoxin外排。這兩個丹參酮可以增加doxorubicin和irinotecan在P-gp過表達的結腸癌SW620 Ad300細胞中的毒性。此外，這兩個丹參酮也增加P-gp底物在SW620 Ad300細胞內的積累，推測是通過下調P-gp的mRNA和蛋白水平，以及抑制P-gp的ATP酶活性。 / 抑制的細胞凋亡可導致腫瘤細胞對促凋亡的抗癌藥物产生多藥耐藥。因此，本研究也探討了cryptotanshinone和dihydrotanshinone能否克服結腸癌細胞的凋亡耐受。結果表明cryptotanshinone和dihydrotanshinone仍然能够杀死耐藥的SW620 Ad300細胞。當與SW620細胞相比，這兩個丹參酮在耐藥細胞中誘導的細胞凋亡較少，但自噬增多。進一步研究表明，這兩個丹參酮誘導的自噬是促進細胞死亡的，從而可以克服細胞的凋亡耐受。 / 此外，p53的缺陷/突變存在於50%以上的人類癌症中，并可以抑制細胞產生凋亡。結果表明，cryptotanshinone和dihydrotanshinone誘導的凋亡和自噬與p53在結腸癌細胞中的表達無關。這兩個丹參酮不依賴於p53的細胞毒性可以用於克服p53缺陷/突變引起的凋亡耐受。 / 綜上所述，本研究結果表明cryptotanshinone和dihydrotanshinone在逆轉P-gp的過表達和抑制的細胞凋亡引起的多藥耐藥中具有巨大潛力。它們可以進一步發展為有前途的治療劑并用於結腸癌的輔助治療，尤其是用於多藥耐藥的結腸癌。 / Hu, Tao. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 163-182). / Abstracts also in Chinese. / Title from PDF title page (viewed on 06, December, 2016). / Hu, Tao. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.