No description available.

No description available.

No description available.

Methotrexate (MTX) has been used for many years in the treatment of patients with cancer as a cytotoxic agent and as an anti-inflammatory drug for the treatment of inflammatory diseases, such as rheumatoid arthritis (RA). However, because of the side effects associated with MTX, there is a continuous search for drugs with less toxicity and hence a greater therapeutic index. In pursuit of a better and less toxic compound, researchers have coupled MTX to various polymeric drug carriers. The objective of this study was to evaluate methotrexate and a methotrexate polymer (D-85) in in vitro and in vivo systems. It was hypothesized that D-85 would show improved anti-neoplastic and anti-inflammatory properties with decreased toxicity compared to MTX. The in vitro experiments included cell viability assays on cancerous and non-cancerous cell lines in order to compare the effects of the two drugs on normal and cancerous cells. Other in vitro assays were performed to assess the effect of the two compounds on cell cycle and mixed lymphocyte cultures. Finally, the toxic effects of both drugs were studied concentrating on two treatment regimens, namely that of an anti-inflammatory regimen and a chemotherapeutic regimen. The results obtained during this study clearly illustrate the chemotherapeutic and anti-rheumatic activity of the two drugs, MTX and D-85. The methotrexate water-soluble drug D-85, however showed greater toxicity towards normal cells compared to the toxicity of methotrexate. / Thesis (MSc (Pharmacology))--University of Pretoria, 2008. / Pharmacology / unrestricted

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A three-part project was devised to investigate the origins of and potential methods to reduce the risk of occupational exposure to cytotoxic drugs. The first phase involved researching the current decontamination methods applied in UK hospital pharmacies, which manipulate cytotoxic drugs. The second phase evaluated practical decontamination methods, and the third phase investigated one intervention aimed at reducing or preventing contamination occurring in an isolator. A questionnaire was sent out to ASU managers in NHS hospital pharmacies to gain information about the disinfection and decontamination procedures and products used. The practical decontamination methods investigated were mechanical removal and degradation by detergents (pH range from 1.7 - 13.2) and cleaning agents, and degradation by vaporised hydrogen peroxide. Analytical methods were developed and validated to recover and quantify the amount of cytotoxic marker drug remaining after the decontamination tests carried out in phase two, and to recover and quantify cytotoxic surface contamination from various surfaces in phase three of this work. This composed an attempt to evaluate the effectiveness of a closed-system e.g. PhaSeal® device for fluid-transfer, in reducing contamination produced from the compounding of cytotoxic drugs in an isolator. The detergents and cleaning agents were effective in removing or reducing cytotoxic surface contamination. Alkaline detergents caused degradation of doxorubicin (maximum 81% at pH 13.2 after 1 hour exposure); the other detergents tested did not xi x degrade the cytotoxic drugs investigated. Exposure to vaporised hydrogen peroxide (1.6g min-1 for 2 hours) caused the degradation of cyclophosphamide (98.9%), 5-Fluorouracil (29.3%), doxorubicin (71.0%) and epirubicin (65.9%) when exposed in pharmaceutical diluents. The closed-system (PhaSeal®) device was effective in reducing contamination produced in an isolator from the compounding of cytotoxic drugs. The risk posed by handling and manipulation of cytotoxic drugs and products to the operator and the environment may be reduced, if not eliminated by considering additional approaches to the methods already in place. Firstly, the application of effective decontamination methods; and secondly, by using an effective closed-system, for example the PhaSeal® drug transfer device in a controlled environment.

As anti-cancer agents, retinoid induce cell growth arrest and differentiation, while HDACIs cause cell differentiation, growth inhibition, death and inhibit angiogenesis in many cancer types. However, a proportion of patients respond poorly to these therapies. My studies, presented here, aimed to improve the anti-cancer effects of these agents by identifying key factors which mediate cancer cell sensitivity or resistance to their action. In this study I have found that the clinically used retinoid, 13-cis RA, exerts its anti-cancer signal in a manner similar to atRA, by modulating the transcriptional response of retinoid-regulated genes. HDACI-induced cytotoxicity is significantly enhanced when combined with IFNα in 8 out of 9 cancer cell lines from various organ origins. Sensitivity to the combination treatment correlated with an absence of basal p21 protein expression, and cell cycle arrest. Knocking-down p21 gene expression further sensitized cancer cells to the combination therapy. Moreover, IFNα and HDACI co-operatively inhibited pro-angiogenic gene expression in cancer cells, and the combination therapy decreased endothelial cell migration, invasion, and capillary tubule formation. Further experiments on p21 as a resistance factor to anti-cancer treatment demonstrated that conditioned media from breast cancer MCF-7 cells transfected with p21 siRNA, induced significantly less endothelial cell migration, invasion and vascular sprouting, compared with media from cells transfected with scrambled siRNA. LC/MS analysis of the conditioned media revealed that Trx secretion was significantly reduced after p21 knockdown. The reduction in Trx secretion following p21 knockdown was due to a direct effect of p21 siRNA on the expression of intracellular TBP2 in neuroblastoma, prostate and lung cancer cells. Consistent with this result, media from MCF7 cells transfected with TBP2-specific siRNA alone, promoted endothelial cell invasion and vascular sprouting, Trx knockdown resulted in opposite effects, and the anti-angiogenic effect of p21 siRNA was offset by simultaneous TBP2 siRNA transfection. ChIP assay revealed that p21 directly bound to an E2F1-bindng site in the TBP2 gene promoter. These data indicate that p21 promoted tumour-driven angiogenesis through transcriptional repression of TBP2. Collectively, my experiments indicate several potential treatment targets directed toward enhancing the effectiveness of HDACIs and retinoids.

No description available.

As anti-cancer agents, retinoid induce cell growth arrest and differentiation, while HDACIs cause cell differentiation, growth inhibition, death and inhibit angiogenesis in many cancer types. However, a proportion of patients respond poorly to these therapies. My studies, presented here, aimed to improve the anti-cancer effects of these agents by identifying key factors which mediate cancer cell sensitivity or resistance to their action. In this study I have found that the clinically used retinoid, 13-cis RA, exerts its anti-cancer signal in a manner similar to atRA, by modulating the transcriptional response of retinoid-regulated genes. HDACI-induced cytotoxicity is significantly enhanced when combined with IFNα in 8 out of 9 cancer cell lines from various organ origins. Sensitivity to the combination treatment correlated with an absence of basal p21 protein expression, and cell cycle arrest. Knocking-down p21 gene expression further sensitized cancer cells to the combination therapy. Moreover, IFNα and HDACI co-operatively inhibited pro-angiogenic gene expression in cancer cells, and the combination therapy decreased endothelial cell migration, invasion, and capillary tubule formation. Further experiments on p21 as a resistance factor to anti-cancer treatment demonstrated that conditioned media from breast cancer MCF-7 cells transfected with p21 siRNA, induced significantly less endothelial cell migration, invasion and vascular sprouting, compared with media from cells transfected with scrambled siRNA. LC/MS analysis of the conditioned media revealed that Trx secretion was significantly reduced after p21 knockdown. The reduction in Trx secretion following p21 knockdown was due to a direct effect of p21 siRNA on the expression of intracellular TBP2 in neuroblastoma, prostate and lung cancer cells. Consistent with this result, media from MCF7 cells transfected with TBP2-specific siRNA alone, promoted endothelial cell invasion and vascular sprouting, Trx knockdown resulted in opposite effects, and the anti-angiogenic effect of p21 siRNA was offset by simultaneous TBP2 siRNA transfection. ChIP assay revealed that p21 directly bound to an E2F1-bindng site in the TBP2 gene promoter. These data indicate that p21 promoted tumour-driven angiogenesis through transcriptional repression of TBP2. Collectively, my experiments indicate several potential treatment targets directed toward enhancing the effectiveness of HDACIs and retinoids.