Despite recent advances in diagnosis and treatment of breast cancer, it still has the highest incidence and mortality of any cancer among women worldwide, and is responsible for more than half a million deaths every year. In recent decades, increased expression and activation of the human epidermal growth factor receptor (HER) family members has been identified in a wide range of cancers. In particular, HER2 is overexpressed in around 25% of all breast cancers and is often associated with poor patient prognosis. As a result, a number of anti-cancer agents targeting HER2 and other members of the HER-family have been approved for the treatment of breast cancer, including the anti-HER2 monoclonal antibodies trastuzumab and pertuzumab, the reversible dual EGFR/HER2 small molcule tyrosine kinase inhibitor (TK1) lapatinib, the antibody-drug conjugate T-DM1, and, more recently, the irreversible pan-HER TK1 neratinib. Despite these advances, however, many patients with HER2 positive (HER2+) breast cancer do not respond to treatment, and many who do later relapse with acquired resistance to the original treatment. The aim of this study was to investigate the sensitivity of a large panel of breast cancer cell lines to treatment with various types of HER-family TKIs, including reversible EGFR-specific, dual EGFR/HER2, and pan-HER TKIs, and irreversible pan-HER TKIs. Additionally the effect of other TKIs with differing targets, including imatinib (BCR-Abl/c-Kit/PDGFR TKI), dasatinib (BCR-Abl/c-Kit/Src TKI), NVP-AEW541 (IGF-1R TKI), crizotinib (ALK/c-Met TKI), and the chemotherapeutic agents paclitaxel and gemcitabine, on the growth of these breast cancer cell lines was also investigated. The association between receptor tyrosine kinase expression and sensitivity of breast cancer cell lines to these agents was also assessed. Furthermore, the mechanisms of action of these agents and their effect on downstream signalling, cell cycle distribution and cell migration were also examined. Of the HER-family TKIs, the second-generation irreversible pan-HER TKIs, particularly afatinib and neratinib, were more effective at inhibiting growth and migration of breast cancer cell lines compared with the first-generation reversible inhibitors (e.g. erlotinib, lapatinib, sapitinib). Furthermore, the irreversible pan-HER TKIs were more effective than the reversible HER-family TKIs at inhibiting phosphorylation of HER-family members and downstream signalling molecules Akt and MAPK. Of the other TKIs, dasatinib was the most effective at inhibiting growth and migration of breast cancer cells, particularly the triple negative cell line MDA-MB-231. Of the chemotherapeutic agents, paclitaxel was the most consistently effective at inhibiting growth of breast cancer cell lines. Combined treatment of TKIs and chemotherapeutic agents were synergistic in some breast cancer cell lines, but no combination was synergistic in all the cell lines tested. Acquired resistance to both lapatinib and afatinib was accompanied by cross-resistance to all other HER-family TKIs and increased sensitivity to dasatinib and gemcitabine. No significant association was found between the expression levels of HER-family members and response to treatment, with the surprising exception of the irreversible pan-HER TKI canertinib. In addition, the role of human papillomavirus (HPV) in breast cancer was also investigated using breast cancer tissue arrays, and of 100 breast cancer tissue samples examined, 24 were found to be positive for the high-risk HPV oncoprotein E7. However, no association was found between E7 positivity and the expression of EGFR, HER2, oestrogen receptor (ER) or progesterone receptor (PR). Further investigations into the potential of irreversible pan-HER TKIs and the BCR-Abl/c-Kit/Src inhibitor dasatinib,as well as the potential benefits of using HER-family TKIs in combination with dasatinib, NVP-AEW541 and gemcitabine, in the treatment of different subtypes of breast cancer are warranted.

There is abundant evidence supporting the health benefits physical activity in cancer survival. Exercise per se is associated with positive physical and psychosocial benefits for survivors of solid tumours. There are limited available research data on blood borne cancers. Lymphoma is one such haematological cancer where survivors often experience decrements in psychosocial, physical functioning and quality of life (QoL) domains. A minority (~25%) of lymphoma survivors meet the recommended public guidelines for exercise. Further to this, the work of Bellizzi and colleagues (2009) indicates that QoL decrements often persist for years following treatment. Conventional wisdom dictates that exercise is likely to be an effective means of alleviating some adverse outcomes from blood borne cancers but this hypothesis is largely untested to date. Further to this, the theory of planned behaviour (TPB) has been shown to provide effectual model for predicting exercise behaviour amongst cancer survivors but known to differ by tumour type. Therefore, the aims of the present thesis were to determine the effects of 12-weeks of a combined aerobic and resistance training programme (CARP) on QoL and health related outcomes in Hodgkin’s lymphoma (HL) and Non-Hodgkin’s lymphoma (NHL) survivors. The thesis focused specifically on four main aims; Aim 1 the primary aim was to identify whether a 12-week CARP is effective at improving QoL in HL and NHL survivors. Secondary Aims were to; Aim 2 to determine whether a 12-week CARP is effective at improving standard measures of muscle function and cardio-respiratory fitness in HL and NHL survivors. Aim 3 to examine whether a 12-week CARP affects inflammatory environment and/or immune function in HL and NHL survivors. Aim 4 to identify whether theory of planned behaviour (TPB) may be an effectual model to predict exercise intention in HL and NHL survivors. In realising these aims, a parallel group randomised control exercise trial (RCT) was conducted with two components. Forty-one (n=41) HL and NHL survivors completed the trial at St George’s hospital, London. Participants, who had completed chemotherapy or radiation treatment (<6 months), were stratified according to tumour type and randomly assigned to either control (CON; n=21) or intervention (INT; n=20). The intervention consisted of a combination of 12-weeks supervised aerobic and resistance training (CARP) whilst the control group received usual care. The first component consisted of three measurement phases; baseline (To; n=41), post-intervention (T1; n=41) for all measurements, and 12 months follow-up (T2; n=15) for qualitative measures. A representative sample (n=6) from the intervention group took part in a focus group to explore participant perception of the impact of the CARP. QoL was assessed using the previously validated European Organization for Research and Treatment of Cancer Quality of Life (EORTC-QLQ-30) questionnaire. Secondary outcome measures consisted of health-related quality of life (HRQoL) determined by Functional Assessment of Cancer Therapy in Lymphoma (FACT-Lym); Mood disturbance and fatigue were determined using Profile of Mood States (POMS) questionnaire; anxiety and depression were determined using Hospital Anxiety and Depression scale (HADS). Participant cardiorespiratory fitness was assessed using the Balke-ware treadmill test, muscle function assessed by grip strength and muscle endurance tests. Blood was sampled using the standard venepuncture method followed by radioimmunoassay to determine interleukin 6 (IL-6) and c-reactive protein (CRP) concentrations. In order to identify determinants of exercise intention and behaviour in HL and NHL survivors, a second component to the trial utilised a validated TPB questionnaire, assessed at baseline (To; n=41), and post-intervention (T1; n=41). Data were analysed using SPSS version 18.0 using appropriate statistical functions. Statistical significance was set at p<0.05. Data are presented as means i standard deviations (S.D.). Results demonstrate that study adherence between To and T1 was 87.2% (41/47) with a large accession rates at 12 months follow up (15/41). Linear mixed models analysis was used to examine subjectively reported outcomes. Clinically relevant improvements in QoL were achieved in both groups at T1. HRQoL, a domain of QoL, increased with exercise; the improvements were both clinically relevant and statistically significant. Subscales of QoL and HRQoL that significantly improved with exercise are social function (p=0.020), emotional well-being (p=0.029), and functional well-being (p=0.025), as well as functional lymphoma specific concerns (p=0.034). Mood disturbance was unchanged in either group, physical function improved only in the control group (p=0.049). Both groups showed improved (p<0.05) physical well-being, vigour, reduced fatigue, and increase in subjectively reported amount of physical activity (IPAQ) as time passed from the end of treatment. At follow-up, HRQoL, lymphoma concerns, fatigue, and the trial outcome index significantly improved in both groups (p<0.05) from baseline; anxiety significantly increased in the intervention and anxiety, physical well-being, and functional well-being improved in the control group. Both groups reduced physical activity at follow-up. Predicted aerobic capacity showed a trend towards an increase, whereas resting heart rate (p=0.041) abdominal muscle endurance (p=0.018) significantly improved in the [NT group with a concomitant trend for a decrease in the CON group. However, this did not reach a level of significance. Although both groups experienced worsening of pulmonary function post intervention, this only reached a level of significance in the ]NT group. No significant changes in either IL-6 or CRP were observed during the study. ANOVA and MANOVA were used to analyse physical outcomes. Regression analysis was used to determine the predictive value of the TPB variables upon intention to exercise, and TPB variables and intention upon actual behaviour. Simultaneous Multiple Regressions were used first to determine the equation for each model. Stepwise Multiple Regressions were used to examine the impact of each variable on the dependent variable to find the best model of prediction. At baseline (both INT and CON groups collapsed to one) the model predicts intention (68.6%), but prediction of variation in actual behaviour is low (36.2%); self- efficacy (13:0.495) and social support (13:0.469) predict intention to exercise among lymphoma survivors and self-efficacy (B=0.609) alone predicts actual behaviour at To. At T1, the model predicts 77.0% of the variation in intention amongst the CON group but only 14.7% of actual behaviour; attitude (B=0.864) predicted intention to behave. Amongst the exercising group, the model predicts 61.5% of the variation in intention, but only 19.2% of actual behaviour; social support (B=0.800) predicts intention to exercise. None of the determinants significantly predicted actual behaviour at T1. The current thesis presents the first data in examination of the impact of a CARP amongst post- treatment lymphoma survivors. The exercise training intervention significantly improved HRQOL and psychosocial well-being. This is noteworthy as lymphoma survivors are often burdened with reduced HRQOL and psychosocial morbidity. Although predicted aerobic fitness levels were statistically unchanged in INT following the intervention, the trend towards an improvement indicates that either an increase in exercise programme length or intensity of exercise sessions may achieve statistical improvement in future studies. The findings from this thesis indicate CARP to be effective in improving psychosocial outcomes in lymphoma survivors. At 12-month follow-up, reduced physical activity was associated with increased anxiety; functional and physical well-being did not improve despite increases seen in CON.

Despite many advances in cancer diagnosis and therapy in the last few decades, pancreatic cancer remains one of the most fatal types of human malignancies, with a 5-year survival rate of less than 6%. One of the major contributing factors for the poor prognosis of this malignancy is the lack of specific markers for its early detection. In addition, pancreatic tumours are highly resistant to conventional types of therapy. Of the numerous anti-cancer agents investigated during the last decade, only erlotinib, an EGFR tyrosine kinase inhibitor has been added to the weaponry against pancreatic cancer. However, the therapeutic benefit of this approach is limited since the majority of patients simply do not respond or eventually acquire resistance to this type of therapy. The aim of this study was to investigate the anti-tumour effect of chemotherapeutic agents such as gemcitabine and several HER and IGF-IR inhibitors, including the pan-HER inhibitor afatinib, when used alone or in combination or 'in vitro'. The expression levels of all HER family members and IGF-IR in a panel of human pancreatic cancer and their association with response to treatment with HER and IGF-IR inhibitors was also investigated. Furthermore, the expression levels of these receptors as well as several ABC transporters and putative pancreatic cancer cell variants developed by chronic treatment with escalating doses of targeted agents or chemotherapeutic agent gemcitabine, of their parental counterparts. All pancreatic cancer cell lines investigated were found to be positive for EGFR, HER-2 and IGF-IR, however, over-expression of these receptors was found to be uncommon. In addition, no correlation was found between the expression levels of HER family members or IGF-IR and sensitivity to their respective inhibitors. Growth inhibition studies revealed that the pan-HER inhibitor afatinib had greater anti-tumour efficacy compared to first generation TKIs erlotinib and gefinitib, supporting its utilization in the treatment of this malignancy. Most importantly, co-targeting of HER family members and IGF-IR was found to be superior to single treatment, providing a rationale for investigating the therapeutic potential of this combination 'in vivo' (animal models and in a clinical setting).

Despite the approval of the anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) cetuximab and panitumumab for the treatment of colorectal cancer patients, there is currently no reliable predictive marker for response to therapy. EGFR is the prototype of human epidermal growth factor receptor (HER) family, which includes three additional members namely HER-2, HER-3 and HER-4. The aim of this study was to investigate the sensitivity of a panel of human colorectal cancer cell lines to treatment with afatinib, an irreversible pan-HER blocker, the EGFR tyrosine kinase inhibitors (TKls) gefitinib and erlotinib, anti-EGFR mAb ICR62 and cytotoxic drugs and to determine whether there was any association between the expression levels of HER family members, the putative cancer stem cell (CSC) markers CD44 and CD133 and ABC transporters (e.g. p-glycoprotein) and response to these agents. The expression pattern and clinical significance of these markers in tumour specimens from 86 Dukes' C and D colorectal cancer patients was determined. Overexpression of the HER family members were found to be uncommon in this panel of human colorectal cancer cell lines, except for EGFR overexpression in DiFi cells. Of the HER inhibitors, afatinib was the most effective agent for inhibiting the growth in vitro of human colorectal cancer cell lines and the expression of HER -4 alone and the co-expression of all the HER family members were associated with response to treatment with afatinib. Acquired resistance of the EGFR overexpressing colorectal cancer cells to treatment with afatinib, ICR62 or gefitinib was accompanied by the up-regulation of EGFR. However, tumour cells that acquired resistance to anti-EGFR mAb ICR62 remained sensitive to treatment with afatinib and vice versa, suggesting that mechanisms underlying the antitumor activity of ICR62 and afatinib are different. The expression ofEGFR, HER-2, HER-3, HER-4 and co-expression of all the HER family members was found in 42.5%, 77%, 52%, 91 % and 18% of the tumour specimens from 86 Dukes' C and D colorectal cancer patients respectively. While all the patients expressed COX-2 and Ki-67, the expression ofCD44 and CD133 was found in 58.6% and 81.9% of the cases, respectively. The expression of EGFR and low expression of Ki-67 were found to be significantly associated with poor disease free survival. The co-expression of HER family members in colorectal cancer patients provides a rationale for investigating the pattern, prognostic significance and predictive value of the HER family members for response to therapy with anti-EGFR mAbs. Further investigations in vivo on the therapeutic potential of pan-HER blockers, such as afatinib, in colorectal cancer patients whose tumours co-express more than one member of the HER family should also be considered.

Mycoplasmas are the smallest and simplest self-replicating prokaryotes, lacking a cell wall and are bound by a single membrane-the plasma membrane. Moreover, mycoplasmas are consequential and chronic pathogens of humans and animals that rely on adhesion to host tissue for colonisation and infections. In other word biofilm formation is correlated with infections and because of this, the biofilm formation of Mycoplasma species has been investigated and characterised in this project. The viability of biofilm formation was assessed and quantified using crystal violet assay over 20-day incubation period. It was noticed that some mycoplasma isolates were capable of forming biofilms more readily than others, which in turn revealed a striking variability in the ability'of Mycoplasmas species to form biofilms. Mycoplasma biofilms and planktonic cells were exposed to environmental stresses, including heat and desiccation to determine their resistance to these stresses. The experiment revealed that mycoplasma biofilms were more resistance to stresses than their planktonic counterparts. The architecture of mycoplasma biofilms was analysed using the combination of two visualisation techniques; CLSM and SEM to determine growth dynamics as well as quantify the biofilm volume over time. The experiment showed that the volume of biofilm become greater when the biofilm gets older. The metabolic patterns of Mycoplasma fermentans and Mycoplasma pneumoniae biofilm cells was investigated and comparing them with their planktonic counterparts in order to characterise the metabolomic changes between planktonic and biofilm cells and thus observe how far their metabolic activities are different.

Chinese herbal remedies (CHRs) are commonly prescribed for the treatment of cancer, however their use is often based on the belief systems of traditional Chinese medicine (TCM), and there is relatively little information regarding their efficacy or biological action. Thus, the aim of this investigation was to select a range of CHRs with some suggestion of tumour modulatory activity, and to devise and implement a strategy with which to investigate their direct toxicity to cancer cells, in an attempt to elucidate their potential efficacy and mode of action. The CHRs ‘OldenIandia diffusa’ (OD), Long Dan Xie Gan Wan (LD), ‘Polygonum multiflorum’ (PM) and ‘Polyporus umbellatus’ (PU) were selected for this investigation, and their direct cytotoxic potential against cancer cells examined using an ‘in vitro’ cell-based system. Initially, water and ethanol extracts of each CHR were made and their toxicity evaluated against a range of cancer cell lines (HL60, HT29, HCT-8, HeLa and CHO). The results of this study suggested that water extracts of OD, LD and PM, but not PU, were significantly toxic to a range of cancer cell types. Further investigation (using the HL60 and HT29 cell lines) suggested that OD and LD induced apoptosis in cancer cell lines ‘in vitro’ through activation of the intrinsic pro-apoptotic signalling pathway (characterised by activation of caspase 9), possibly through the induction of genotoxic damage, and that this activity was related to the combined actions of a number of cytotoxic compounds, and not to a single constituent. Furthermore, OD and LD were found to be less toxic to cultured primary blood lymphocytes (PBLs), thus further suggesting that there may be some scientific basis for their use in the treatment of cancer. Further investigation into the cytotoxic action of water extracts of PM revealed that it was inducing necrosis in cancer cell lines and not apoptosis, thus suggesting that PM does not possess anticancer activity. Overall, the results of this investigation suggest that OD and LD may be a source of novel chemotherapeutic agents, and that there may be some scientific basis for their traditional use in the treatment of cancer.

Enzymes such as aromatase, 17[beta]-hydroxysteroid dehydrogenase [types 1 (17[beta]-HSD1) and 3 (17[beta]-HSD3)] and estrone sulfatase (ES) are all involved in the biosynthesis of steroids via the steroidal cascade. The inhibition of these enzymes may lead to a reduction in the levels of steroids present, thereby leading to a decrease in the stimulation of hormone-dependent tissues, in particular, hormone-dependent breast and prostate cancers. This approach has proved to be successful in postmenopausal women where the use of aromatase inhibitors has led to the decrease in tumour yield and has thus led to the treatment of the disease. Within the current study, the synthesis and biochemical evaluation of a number of compounds of varying structural features has been undertaken, in particular, the synthesis of sulfonate derivatives of 4-hydroxyphenyl ketone - the parent compound having already been shown to be a potent inhibitor of 17[beta]-HSD3 (with good specificity towards 17[beta]-HSD3) and the synthesis of a range of alkyl and cycloalkyl esters of steroids [in particular, testosterone (T) dehydroepiandrosterone (DHEA) and estrone (E10] as probes of the active sites of the HSD family of enzymes. The results show that the sulfonate (methanesulfonate and trifluromethanesulfonate) derivatives of 4-hydroxyphenyl ketone-based compounds were found to possess weak inhibitory activity against all three HSD enzymes considered (namely, 17[beta]-HSD1, 17[beta]-HSD3 and 3[beta]-HSD) in comparison to the parent 4-hydroxyphenyl ketone-based compounds. For example, within the methanesulfonate derivatives, methane sulfonic acid (4-cyclohexane carbonyl)-phenyl ester (164) was found to be the most potent inhibitor against 17[beta]-HSD3, however, it possessed ~30% inhibitory against this enzyme at an inhibitor concentration of 100[mu]M. Against 17[beta]-HSD1, the most potent compound within the same range was also compound 164 which pssessed ~45% inhibitory activity under similar conditions. Within the trifluromethane sulfonate derivatives, the most potent compounds proved to be extremely weak inhibitors of 17[beta]-HSD3, however, against 17[beta]-HSD1, the most potent compound was trifluromethane sulfonic acid 4-benzoyl-phenyl ester (180) which possess 43% inhibitory activity. The molecular modeling of these compounds within representations of the active sites of 17[beta]-HSD1 and 17[beta]-HSD3 shows that the lack of inhibitory activity is due to steric hindrance, in particular, the sulfonate moeity undergoes steric hindrance with groups at the active site which is close to the C(17) area of the natural substrate. The synthesis of the esters of T, DHEA and E1 and the subsequent biochemical evaluation of these compounds resulted in an interesting structure-activity relationship. In general, the compounds based on DHEA were found to be potent inhibitors of 17[beta]-HSD3 with weak inhibitory activity against 17[beta]-HSD1 and 3[beta]-HSD. For example, DHEA acetate (196) was found to possess an IC[sub]50 value of 0.74[mu]M in comparison to the most potent standard, namely 1-(4hydroxy-phenyl)-nonan-1-one (139) which was found to possess an IC[sub]50 value of 12.32[mu]M - this compound was found to possess good selectivity as it possessed ~40% and ~25% inhibitory activity against 17[beta]-HSD1 and 3[beta]-HSD respectively at an inhibitor concentration of 100[mu]M. The esters of E1 and T proved to be weaker inhibitors in comparison to the esters based on DHEA, however, the E1-based esters also showed some selectivity towards 17[beta]-HSD3. For example, E1 hexanoate (216) possessed an IC[sub]50 value of 37.28[mu]M and possessed 45% and 35% inhibitory activity against 17[beta]-HSD1 and 3[beta]-HSD respectively at an inhibitor concentration of 100[mu]M. The modelling of these compounds (using representations of the active sites of 17[beta]-HSD1 and 17[beta]-HSD3) showed that the lack of inhibitory activity was due to steric interactions between the inhibitors and groups within the active site. As such, these compounds proved to be extremely useful probes of the active sites of 17[beta]-HSD1 and 17[beta]-HSD3 and have further enhanced the models used in the design of these compounds.

The majority of prostate cancer cases are shown to be androgen-dependant for growth as the blocking of androgen production has shown to reduce the size of prostate metastasis. The biosynthesis of the androgens is catalysed by the cytochrome P450 enzyme 17a-hydroxylase/17,20-lyase (P45017a) by converting the C21 steroids (pregnenolone and progesterone) to the androgens (dehydroepiandrosterone and androstenedione, respectively). Inhibition of P45017a would therefore bring about a decrease in the level of androgen production and furthermore prevent an increase in the stimulation of androgen-dependent prostate cancer cells. The current study was concerned with designing and synthesising compounds which were able to donate a lone pair of electrons to the Fe atom of the haem group with in the active site of the enzyme P45017a. As well as this, we were also interested in being able to mimic the C(3) of the natural substrate by varying the R group. In doing so, we were able to observe the impact of the interactions which take place within the active site. The compounds synthesised are based on the benzyl imidazole and the imidazolphenyl ethanonebackbone, where a small number of the synthesised products are phenyl alkyl imidazole based compounds, in order to consider physiochemical factors like hydrophobicity. Overall, the results of the study showed that the benzyl imidazole-based compounds were comparable to that of the standard ketoconazole (KTZ) in their inhibitory activity against 17,20-lyase and 17a-OHase (KTZ; %inhibition = 75% against 17,20-lyase: %inhibition = 64% against 17a-OHase). The nitro substituted derivatives (270-272) were shown to have improved inhibitory activity when compared to KTZ against 17a-OHase. With respect to the imidazol-phenyl ethananes, all with the exception of the 3-bromo substituted derivative ~88) were shown to possess either equipotent inhibitory activity to that of KTZ (%inhibition = 80% against 17a-OHase: %inhibiton = 82% against 17,20-lyase) or substantially lower activity. Compound 288 was found to possess greater inhibitory activity against the 17a-OHase component (288 %inhibition = 84%). Deliberation of structure-activity relationships determined no obvious correlation between the substitution pattern of the benzyl ring and the inhibitory activity against 17,20-lyase in the benzyl imidazole-based compounds. However, in the activity against 17a-OHase, a general trend towards the para substitution of the benzyl ring was shown to have an impact on the inhibition of the enzyme. In the imidazol-phenyl ethananes, consideration of the inhibitory activity of the halogen derivatives shows that there is an increase in potency with decreasing electronegativity of substituent group. In the inhibitory activity against 17a-OHase, some compounds show a correlation between decreasing electron-withdrawing ability and an increase in percentage inhibition. This would therefore appear to suggest that an ·interaction exists between the substituent and complementary group(s) at the active site of the enzyme - this interaction appears to be weaker within derivatives which possess substituents of high electronegativity. The substitution of the phenyl ring was too shown to influence the inhibitory activity of the compounds, which was rationalised by use of the SHC approach. This was proposed as results clearly indicate that the meta-substituted compounds were found to possess greater inhibitory activity in comparison to the para-substituted compounds.

It has been shown that the majority of benign prostatic hyperplasia (BPH) and prostate cancers are dependent on androgen production within the body. The biosynthesis of androgens is catalysed by different enzymes however one of the enzymes, 17 beta-hydroxysteroid dehydrogenase type 3 (17 beta-HSD3), converts the C(17)=O carbonyl moiety of androstenedione (1l4-dione) to the corresponding C(17)-OH hydroxyl group of testosterone (T). It has been hypothesised that inhibition of 17 beta-HSD3 may cause a decrease in the level of androgens which in turn leads to a reduction in the genesis of androgen-dependent prostatic diseases. The utilisation of enzyme inhibition as a therapeutic agent, in the treatment of breast cancer, has been tested on postmenopausal women by using aromatase inhibitors (e. g; exemestane, anastrazole and latrazole). This approach has proved to be successful and the impact of enzyme inhibition was led to a reduction in cancer growth. This process has now found a clinical application. From molecular modelling studies it was postulated that any potential inhibitor of 17 beta-HSD3 should contain a carbonyl moiety, mimicking the C(17)=O of the natural substrate, as well as an aromatic ring adjacent to the carbonyl group. With these criteria in mind results from our laboratories showed that from a library of candidates those based upon 4-hydroxyphenyl ketones showed some potential. The main focus of this prestn study was to fine tube the enzyme inhibitor analogues and hence optimise inhibitory activity of 4-hydroxyphenyl ketones. We have successfully synthesised a range of novel derivatives of 4-hydroxyphenyl ketones such as the 4-methanesulfonate and 4-acetate ester derivatives. In general, the reactions have proceeded very well with the yields ranging from 65% to 88% and 91% to 97% respectively. The results of biochemical evaluation studies suggested that the acetate ester derivatives, in particular compounds (149) and (150) exhibited good inhibitory activity against 17 beta-HSD type 3 of about 40% compared to standard inhibitors such as 7-hydroxyflavone and baicalein which resulted in about 13% and 14% inhibitory activity respectively. In addition a range of non-steroidal B, C, D ring mimics of the natural substrate of 17 beta-HSD type 3 were synthesised in good yields (65% to 85%). The biochemical evaluation of these compounds also showed good inhibitory activity; in fact compound (107) exhibited about 43% inhibition in comparison to the above standards which had inhibition of about 25% and 31 % respectively. In conclusion we have successfully synthesised and biochemically evaluated a number of enzyme inhibitors for the enzyme 17 beta-HSD type 3. The two types of active inhibitors were structurally dissimilar suggesting that they may have different modes of binding. This outcome requires further investigation in order to establish and identify how this inhibition is taking place.

Androgens play an important part in the initiation and progression of hormone-dependent prostate and breast cancer. These types of cancers can be treated by androgen ablation therapy. However, androgen ablation is associated with short (2-3 years) remission of the disease. Therefore therapies that inhibit the systemic biosynthesis of androgens, by targeting the P450 enzymes (CYP17 and 17-[beta]HSD type 3) which catalyse androgen biosynthesis, may represent a rational approach in the treatment of androgen-dependent cancer. Inhibitors of the enzyme CYP17: ketoconazole and liarozole, have been shown to decrease tumour cell adhesion to the endothelium and expression of adhesion molecules. The adhesion of cancer cells to the endothelium is an important preliminary event that underlies cancer matastasis. Within the this study, the development of assays for the enzymes; CYP17 and 17[beta]-HSD3 and the evaluation of a series of compounds which were designed to inhibit these enzymes have been considered. The preliminary screening of the compounds showed good inhibition of 17[alpha]=OHase and 17, 20 lyase components of the CYP17 enzyme in comparison to the reference drug, ketoconazole (KTZ). The IC[sub]50 of compounds 31, 34, 38, 41, 48 and 51 and KTZ was calculated as 14.40 [Mu]M, 5.82 [Mu]M, 0.18 [Mu]M, 1.35[Mu]M, 1.21[Mu]M, 0.50[Mu]M and 5.65[Mu]M respectively. However, only a few of the compounds designed to inhibit 17[beta]-HSD3 showed ap potent inhibitory activity. Compound 132 showed the highest percentage inhibition (40.51 [plus or minus] 0.14%) of 17[beta]- HSD3 activity when compared to the reference drugs, 7-hydroxy flavone (12.90 [plus or minus] 0.31%) and biacalein (13.66 [plus or minus] 0.31%). CYP17 inhibitors did not have any cytoxic effect on human cancerous and non-cancerous cell lines. The adhesion of DU145, PC3 and MCF7 to a non-stimulated HUVEC monolayers was decreased from 100 [plus or minus] 0.01% cell adhesion to 60.93 [plus or minus] 3.95%, 65.79 [plus or minus] 9.39% and 65.12 [plus or minus] 4.04% by compounds 38. 48 and 51 respectively in the absence of tumour necrosis factor alpha (THF-[alpha]). Similarly, compounds 38, 48 and 51 showed the highest anti-adhesion effect of DU145 on stimulated HUVEC monolayers (69.85 [plus or minus] 2.51%) cells respectively. Flow cytometry and immunostaining of intracellular adhesion molecules showed that CYP17 inhibitors did not have any effect on the expression of ICAM-1. In conclusion, the synthesised compounds were found to be good indicators of the CYP17 enzyme with no cytoxic and better anti-adhesion effects when compared to KTZ. Thus, these compounds can be further investigated as a therapeutic strategy against hormone-dependent prostate and breast cancer.