Thesis submitted to the Faculty of Science under the school of Molecular and Cell Biology, University of the Witwatersrand, in partial fulfilment of the requirements for PhD. Gauteng, Johannesburg, 2015 / Cancer is an enormous burden of disease, accounting for millions of deaths annually worldwide. Today, more people are dying from cancer than HIV/AIDS, malaria and tuberculosis combined. According to the American Cancer Society, it is expected that the global cancer burden will double by 2030 if preventative measures are not applied. Breast and gynaecological cancers remains a big scourge in developing countries, with breast cancer being the most common cancer and gynaecological cancers accounting for approximately 25% of all cancers in women in developing countries. Currently, the standard cancer treatments include surgery, radiation and chemotherapy. Adverse toxicities have been associated with these therapies and their effectiveness is also limited to drug resistance. The cost of treatment is another major burden. Limitations associated with these conventional cancer treatments have made discoveries of novel therapeutics which exhibit less toxicity and at a lowered cost of paramount importance. Medicinal plant extracts have recently attracted attention to modern medical science research with their non-lethal activity. Currently, up to 50% of the world drugs including chemotherapeutic drugs such as taxol and camptothecin are made from natural products or their derivatives. In this study we aimed to investigate the anti-cancer properties of the medicinal plant Euphorbia tirucalli. The crude extracts of E. tirucalli extracted using butanol; hexane and methanol solvents were screened for antiproliferative activity in breast (MCF-7 and MDA-MB231), ovarian (RMG-1) and cervical (SiHa) cancer cell lines. MTT assay and Real-Time Cell Analyzer (RTCA), xCELLigence were used to determine cytotoxicity of the extracts and calculate IC50. From MTT and xCELLigence results, we observed that E. tirucalli extracts exhibited dose-dependent inhibition of cell proliferation with RMG-1 and MCF-7 cells being more sensitive than MDA-MB231 and SiHa cells to all three extracts for an unclear reason. The butanol extract appeared to exhibit iv the most cytotoxicity with all cell lines reaching IC50 at low extract concentrations. Most therapies in anticancer treatment, such as chemotherapy, mainly induce cell death by causing either G0/G1 or G2/M cell cycle arrest and then inducing an apoptotic pathway. Therefore, cell cycle arrest and the induction of apoptosis in cancer cells become the major indicators of anticancer effects. Cells were stained with propidium iodide dye to determine if cells were arrested at G0/G1 or G2/M cell cycle stages while annexin V and PI staining were used to determine the type of cell death induced by the extracts. Cell cycle analyses revealed MCF-7, MDA-MB231 and SiHa cancer cells underwent arrest at G0/G1 following treatment with the plant extracts. Annexin V and PI staining revealed different proportions of apoptotic and necrotic populations. The extracts mainly induced apoptosis on MCF-7 and MDA-MB 231 cells, with the butanolic extracts inducing the most apoptosis. RMG-1 and SiHa cells had a high proportion of cells undergoing both late apoptosis and necrosis. The molecular mechanism of cell death induction was investigated using real time PCR and western blot. From the gene expression studies, p21 was observed to be over expressed in all cells following all treatments, in line with the observed cell cycle arrest at G0/G1. The extrinsic pathway of apoptosis was identified as the type of cell death induced with caspase 8 being overexpressed in MDA-MB 231 cells treated with butanol and hexane extracts. Upon further fractionation, flavonoids and especially isorhamnetin were identified as the active compounds in these extracts. Overall, the plant contains compounds that have some activity against cell proliferation and can be a promising tool to treat cancer cells. However, more work needs to be done to verify which compounds are mainly involved.

Accelerated Partial Breast Irradiation (APBI) is a common treatment of breast cancer with many modalities including 3D Conformal Radiation Therapy (3D-CRT), Intensity Modulated Radiation Therapy (IMRT), and High Dose Rate Brachytherapy (HDR). In this research, a retrospective analysis of patient’s data was performed to analyze the NTCP/TCP (Normal Tissue Complication Probability/Tumor Control Probability) and Dose Volume Histogram (DVH) parameters for HDR with SAVI, 3D, and IMRT and compare them focusing on critical organs such as the heart, ipsilateral lung, chest wall, ribs, and skin. TCP was 90.275%, 55.948%, and 53.369% for HDR, 3D, and IMRT respectively. The ribs were the most sensitive critical organ for all 3 modalities with a mean NTCP of 8%, 15%, and 8% for HDR, 3D, and IMRT respectively. DVH analysis showed HDR spares critical organs more than EBRT except for 2 patients receiving high doses to the ribs and chest wall. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Doctor of Health Science / It is well documented that for prostate cancer patients undergoing radiation therapy there is a correlation between target volume displacement and changes in bladder and rectal volumes. However, these studies have used a methodology that has captured only a subset of all treatment positions. This research used daily Computer Tomography (CT) imaging to comprehensively assess organ volumes, organ motion and their effect on dose, something that has never been performed previously, thus adding considerably to the understanding of the topic. Daily CT images were obtained using a Siemens Primus Linear Accelerator equipped with an in-room Somatom CT unit in the accelerator suite, marketed as ‘Primatom’, to accurately position the patient prior to treatment delivery. The internal structures of interest were contoured on the planning workstation by the investigator. The daily volume and location of the organs were derived from the computer to assess and analyse internal organ motion. The planned dose distribution was then imported onto the treatment CT datasets and used to compare the planned dose to i) the actual isocentre, where the isocentre was actually placed for that fraction, ii) the uncorrected isocentre, by un-doing any on-line corrections performed by the treatment staff prior to treatment delivery, and iii) the future isocentre, by placing the isocentre relative to internal organ motion on a daily basis. The results of this study did not confirm a statistically significant decrease in rectum volumes over time (hypothesis 1), however large fluctuations in bladder volume were confirmed (hypothesis 2). Internal organ motion for the rectum and bladder was demonstrated to be related to organ filling. Ideal planning volumes for these organs have been reported to minimise systematic and random uncertainty in the treatment volumes. An observed decrease in prostate volume over time, a systematic uncertainty in the location of the prostate at the time of the planning CT scan and a significant relationship between prostate centre of volume and rectum and bladder volumes has resulted in a recommendation that patients should be re-scanned during treatment to ensure appropriate clinical target volume coverage. A significant relationship between rectal and bladder volumes and the dose delivered to these organs was found (hypothesis 3). The dose delivered to the planning target volume was not related to the rectal or bladder volumes, although it was related to the motion of these organs. Despite these results only minimal effects on the dose delivered to any of the three isocentres occurred, indicating that the planned dose was accurately delivered using the methodology presented here (hypothesis 4). However the results do indicate that the patient preparation instructions need to be improved if margins are to be reduced in the future. It is unrealistic to assume that Image Guided Radiation Therapy will ever become routine practice due to infrastructure costs and time limitations. This research will inform radiation therapy centres of the variables associated with prostate cancer treatment on a daily basis, something that has never before been realistically achievable. As a result centres will be able to devise protocols to improve treatment outcomes.

Thesis (M.S.)- -University of Puerto Rico, Mayagüez Campus, 2005. / Tables. Printout. Includes bibliographical references (leave 72)

p38 mitogen-activated protein kinases (MAPKs) control the endocytic trafficking of various growth-related cell surface receptors and transporters. Herein, I demonstrate that p38 MAPKs also regulate autophagy, or the process of self-cannibalism. In my studies, inhibition of p38 MAPKs triggered rapid formation of autophagosomes in prostate cancer cells, even under nutrient-rich conditions, and remarkably, the autophagosomal membranes emanated from endoplasmic reticulum exit sites via the concerted actions of the small GTPases, ARF1 and SAR1. Once formed, the autophagosomes fused with late endosomes and/or lysosomes, in a Rab7-dependent manner, to form “hybrid organelles” that were co-labeled with ER, autophagic, late endosomal, and lysosomal markers. Unlike other inducers of autophagy, however, inhibition of p38 MAPKs suppressed the fission of hybrid organelles, resulting in a profound but reversible accumulation of large cytoplasmic vacuoles. Thus, in addition to their previously reported roles in endocytosis, p38 MAPKs appear to coordinately regulate autophagy and the downstream biogenesis and fission of hybrid organelles. / text

published_or_final_version / Surgery / Master / Master of Philosophy

published_or_final_version / Surgery / Doctoral / Doctor of Philosophy

published_or_final_version / Anatomy / Master / Master of Philosophy

published_or_final_version / Public Health / Master / Master of Public Health

 Hepatocellular carcinoma (HCC) is the primary cancer of liver. It is the fifth common malignant tumor in men while seventh common in women. Aetiology of HCC is complex; however, it is now believed that sustained chronic liver injury and fibrosis are critically involved in the development of HCC. Prevention and treatment of HCC is far from desirable and prognosis remains poor. Coptis is a Chinese herbal Medicine which has been used for more than thousands years for clearing heats, dampness and toxics. Recently, studies from our group reported the hepatoprotective effect of Coptis and its major active component, berberine, on acute liver injury and berberine was extensively studied for their anti-tumor effect. However, there’s no comprehensive investigation focusing on the preventive and curative potential of berberine on HCC. Hence, here we hypothesized Coptis and berberine exhibits both preventive and curative effects on HCC. The prevention of HCC by berberine and Coptis may rely on their effects on chronic liver damage and fibrosis, and the curative action may depend on their actions on the angiogenesis, tumor growth and invasion of HCC. Both in vitro cell models and in vivo animal system were used in our study and some molecular events were investigated. We found that berberine and Coptis could significantly attenuate the chronic liver injury and fibrosis by restoring the anti-oxidative enzyme SOD activity in CCl4-, bile duct ligation- and alcohol-induced liver injury and fibrosis model. Recovery of SOD activity prevents the hepatocytes from apoptosis by inhibiting the oxidative stress-induced Erk1/2 signaling activation. The prevention of berberine and Coptis on chronic liver injury and fibrosis may contribute to its preventive effect against HCC. Then we found that berberine (as representative to Coptis) could suppress the angiogenesis of HCC, in which berberine does not directly act on the blood vessel formation, but suppress the expression and secretion of pro-angiogenic factors VEGF in HCC cells, and Id-1 inhibition by berberine plays a central role in the suppression of HIF-1α/VEGF and NF-κB pathways. We also found that berberine could induce both apoptotic and autophagic cell death in HCC, and the mitochondria related-caspases activation confers the apoptosis while mTOR inhibition initiates autophagy in berberine treated- cells. We found that berberine could suppress the migration and invasion of HCC cells as well, and Rho-GTPases/ROCK signaling is the particular target in berberine’s anti-invasive action. Finally, to dig out some molecular events involved in berberine’s action on HCC, we studied critically the mechanism underlying berberine’s inhibition on Cyclin D1 in HCC. We found berberine may promote the IKKα-induced Cyclin D1 phosphorylation at T286, and this may initiate the ubiquitination-dependent proteasomal degradation of Cyclin D1 in berberine-treated HCC cells and contribute to berberine’s anti-HCC action. Critical clinical trials and OMICS techniques were planned to further our comprehensive study on Coptis and berberine’s effects on HCC. In all, we found that berberine targets on different stages and molecules and exerts preventive and curative potential against HCC. Our study sheds light on the clinical application of berberine in HCC treatment. / published_or_final_version / Chinese Medicine / Doctoral / Doctor of Philosophy