The 3-dimensional Structure Of Anticancer Drug-DNA Complexes Determined By X-ray Crystallography
Funder
National Health and Medical Research Council
Funding Amount
$264,358.00
Summary
Our main objective is to discover the molecular details of how cancer drugs interact with DNA and how these interactions differ from those of inactive chemically related compounds. We propose to use X-ray crystallography together with the successful methods we have developed for determining the 3-dimensional structures of the DNA complexes of a class of antitumour active drugs to study the complexes of other clinically or scientifically important DNA intercalating anticancer drugs. These agents ....Our main objective is to discover the molecular details of how cancer drugs interact with DNA and how these interactions differ from those of inactive chemically related compounds. We propose to use X-ray crystallography together with the successful methods we have developed for determining the 3-dimensional structures of the DNA complexes of a class of antitumour active drugs to study the complexes of other clinically or scientifically important DNA intercalating anticancer drugs. These agents act by poisoning the DNA binding enzyme topoisomerase. Crystallographic analysis will give us unequivocal answers at the atomic level as to the exact way in which the drug binds to DNA and how this binding differs between antitumour active and inactive compounds. We believe that a knowledge of the DNA binding mode of a class of intercalating anticancer drugs at the atomic level is valuable in guiding drug design within that class.Read moreRead less
The Structural Basis For The Action Of Anticancer DNA-intercalating Topoisomerase Poisons
Funder
National Health and Medical Research Council
Funding Amount
$459,750.00
Summary
Cancer kills one in four people in the Western world and half of those afflicted will die from the disease. If the malignancy is detected early, surgery and radiotherapy will often effect a cure but if the disease is disseminated at presentation then treatment requires chemotherapy. Chemotherapy can be curative for some tumour types but it is generally only palliative for the overwhelming majority of solid cancers. Consequently, there is an urgent need to improve the efficacy of anticancer drugs ....Cancer kills one in four people in the Western world and half of those afflicted will die from the disease. If the malignancy is detected early, surgery and radiotherapy will often effect a cure but if the disease is disseminated at presentation then treatment requires chemotherapy. Chemotherapy can be curative for some tumour types but it is generally only palliative for the overwhelming majority of solid cancers. Consequently, there is an urgent need to improve the efficacy of anticancer drugs. Many of these drugs work by binding directly to DNA and poisoning the DNA-manipulating enzyme, topoisomerase. Our objective is to discover the molecular basis of how anticancer drugs act through their interaction with DNA and topoisomerase. We propose to use the successful X-ray crystallography methods we have developed for determining the 3-dimensional structures of the DNA complexes of a class of anti-tumour active drugs, to study the complexes of other clinically or scientifically important DNA intercalating anticancer drugs. Crystallographic analysis provides unequivocal data, at near atomic resolution, of the nature of the molecular interactions which provide specificity and selectivity in drug-DNA complexes. This information will be a valuable guide in the further development of this important class of topoisomerase poisons as anticancer drugs. We will initiate structural studies of ternary complexes between the topoisomerase enzyme, DNA and anticancer drugs. The solution of the X-ray crystal structures of these ternary complexes will allow the design of new antitumour topoisomerase poisons to be put on a completely rational basis.Read moreRead less
Synthetic Analogues Of The Actinomycin, Quinamycin And Nogalamycin Groups Of Antitumour Antibiotics
Funder
National Health and Medical Research Council
Funding Amount
$376,433.00
Summary
The principal difficulty in the treatment of the common solid tumours that cause the majority of cancer deaths is the problem of drug resistance. For example, many patients with cancer of the lung, breast or colon respond well to drug treatment with their tumours initially regressing, only to return later in an aggressive drug-resistant form. In this event, the inevitable outcome is that the tumour grows through drug treatment and the patient eventually succumbs and dies. This is also a familiar ....The principal difficulty in the treatment of the common solid tumours that cause the majority of cancer deaths is the problem of drug resistance. For example, many patients with cancer of the lung, breast or colon respond well to drug treatment with their tumours initially regressing, only to return later in an aggressive drug-resistant form. In this event, the inevitable outcome is that the tumour grows through drug treatment and the patient eventually succumbs and dies. This is also a familiar scenario in the treatment of adults with leakaemias and non-Hodgkins lymphomas. The underlying cause of drug resistance is the genetic instability of cancer cells which results in tumours that are heterogeneous, making it almost inevitable that a cancer cell will arise that is resistant to treatment. There are many mechanisms of resistance, some of which are peculiar to particular drug types, some are permeability barriers and some involve genetic deregulation of the biochemistry of cell death. One way of subverting resistance is by the use of drugs whose mechanism of action is novel so that the tumour is challenged to devise a new defense. Here, we are attempting to develop synthetic analogues of a class of naturally- occurring antitumour antibiotic whose mechanism of action is unusual but which has not been exploited by medicinal chemists because of the difficulty of the chemistry involved. These antibiotics work by binding to DNA and inhibiting the first step in the process whereby genes are turned into proteins. We have designed compounds that are chemically accessible that our preliminary work suggests mimic the DNA-binding and biological properties of the natural antibiotics. The proposed work will enable us to evaluate whether this new class of agent has experimental antitumour activity, particularly amongst drug-resistant tumours.Read moreRead less
Development Of DNA Phosphate Crosslinking Agents As Potential Anticancer Drugs
Funder
National Health and Medical Research Council
Funding Amount
$392,545.00
Summary
The principal difficulty in the treatment of the common solid tumours that cause the majority of cancer deaths is the problem of drug resistance. For example, many patients with cancer of the lung, breast or colon respond well to drug treatment with their tumours initially regressing, only to return later in an aggressive drug-resistant form. In this event, the inevitable outcome is that the tumour grows through drug treatment and the patient eventually succumbs and dies. This is also a familiar ....The principal difficulty in the treatment of the common solid tumours that cause the majority of cancer deaths is the problem of drug resistance. For example, many patients with cancer of the lung, breast or colon respond well to drug treatment with their tumours initially regressing, only to return later in an aggressive drug-resistant form. In this event, the inevitable outcome is that the tumour grows through drug treatment and the patient eventually succumbs and dies. This is also a familiar scenario in the treatment of adults with leukaemias and non-Hodgkins lymphomas. The underlying cause of drug resistance is the genetic instability of cancer cells which results in tumours that are heterogeneous, making it almost inevitable that a cancer cell will arise that is resistant to treatment. There are many mechanisms of resistance, some of which are peculiar to particular drug types, some are permeability barriers and some involve genetic deregulation of the biochemistry of cell death. Alkylating agents are one of the most important classes of anticancer drug. They bind irreversibly to the bases in DNA and weld the two strands of the double helix together. This cross-link is a powerful block to DNA replication and leads to the death of cancer cells by the process of programmed cell death. Cancer cells generally become resistant to alkylating agents by invoking repair mechanisms that remove the drug from the DNA bases, a response which breaks the cross-link and returns the DNA to its normal state. In this project, we are developing a new type of alkylating agent that reacts not with the DNA bases but with the phosphate groups of the DNA backbone. By this means the strands of DNA can again be cross-linked but now the linkage is between parts of the DNA that cancer cells cannot separate. In this way, we hope to be able to devise new drugs that are resistant to the normal mechanisms of DNA repair so that they will be active against drug-resistant tumours.Read moreRead less
Depression, Anxiety And Somatic Distress: Syndromal Structure And Relationship To Onset Of Clinical Disorder
Funder
National Health and Medical Research Council
Funding Amount
$224,085.00
Summary
The project aims to identify the principal dimensions or syndromes underlying symptoms of psychological distress (negative emotional states such as depression, anxiety, stress and fatigue). We plan to use an intensive longitudinal design to examine how these syndromes develop into episodes of clinical disorder. We expect that episodes of disorder will be predicted not only by closely related syndromes, but also by other causally related syndromes - for example, a period of increased anxiety and ....The project aims to identify the principal dimensions or syndromes underlying symptoms of psychological distress (negative emotional states such as depression, anxiety, stress and fatigue). We plan to use an intensive longitudinal design to examine how these syndromes develop into episodes of clinical disorder. We expect that episodes of disorder will be predicted not only by closely related syndromes, but also by other causally related syndromes - for example, a period of increased anxiety and stress may precipitate a depressive disorder. This information is important for understanding the aetiology of clinical disorders, for refining diagnostic criteria, and for the prediction and prevention of disorder. We also plan to collect information about the degree of disability that people suffer and the type of health services they access at various levels of severity of each syndrome. We expect that subclinical levels of some syndromes will be associated with substantial impairment and service usage, but that for other syndromes impairment will be minimal until clinical levels of severity are reached. This information will give a more complete picture of the community-wide burden of emotional distress, and will be directly relevant to health planning and policy.Read moreRead less
Combined linear and angular head movements are integral components of our natural head movements. The vestibular sensory apparatus in the labyrinth of the inner ear, which comprises three semicircular canals and two otoliths acts as an inertial guidance system during head motion. The vestibular sensors mediate the angular and linear vestibulo-ocular reflexive eye movements imperative to stabilise vision during the head motions. However, it is unclear how these responses to sudden linear and angu ....Combined linear and angular head movements are integral components of our natural head movements. The vestibular sensory apparatus in the labyrinth of the inner ear, which comprises three semicircular canals and two otoliths acts as an inertial guidance system during head motion. The vestibular sensors mediate the angular and linear vestibulo-ocular reflexive eye movements imperative to stabilise vision during the head motions. However, it is unclear how these responses to sudden linear and angular motion in three dimensions are combined and processed. Diseases of the inner ear can produce incapacitating visual and balance disturbances, yet the normal function of some of the inner ears receptors, in particular the otoliths, cannot be easily tested. Clinical evidence has shown that patients with incapacitating attacks of vertigo can have impairment of either or both the semicircular canals and the otoliths. The aim of this project is to measure quantitatively the semicircular canal-otolith response to transient, high-acceleration combined linear-angular head movements to find a reliable way to test the otolith function. Based on physiological principles and my preliminary experiment, we plan to use an off-axis head rotation procedure, a three-dimensional eye movement recordings and vector analysis technique to assess the linear and angular vestibulo-ocular reflex response from the otoliths and semicircular canals in the labyrinth. The practical significance of answers to these questions is that they will characterise the combined linear and angular vestibulo-ocular reflex responses that stabilise vision during transient head movements. It will provide us with a greater understanding of the visual disturbance that patients experienced during these kinds of head movements following vestibular disease or surgery. Measurement of the linear vestibulo-ocular reflex may also provide a diagnostic test of otolith function clinically in disease states.Read moreRead less
The Regulation Of 14-3-3 Protein Function By Post-translational Modification
Funder
National Health and Medical Research Council
Funding Amount
$212,036.00
Summary
The cells of our body have control mechanisms that prevent them from growing abnormally. However, when cells become cancerous they escape the normal checks and controls and are able to survive, divide and grow uncontrollably. In the last decade the molecular basis of several of the control mechanisms involved in preventing cancerous growth have been uncovered. However, our understanding is far from complete and recent research reports suggest that we have thus far overlooked a whole level of reg ....The cells of our body have control mechanisms that prevent them from growing abnormally. However, when cells become cancerous they escape the normal checks and controls and are able to survive, divide and grow uncontrollably. In the last decade the molecular basis of several of the control mechanisms involved in preventing cancerous growth have been uncovered. However, our understanding is far from complete and recent research reports suggest that we have thus far overlooked a whole level of regulation of cell growth control. Signals that instruct a normal cell to divide are propogated by pathways of interacting molecules within the cell. These pathways are regulated by switch mechanisms that either modify the interacting molecules, thereby inactivating their activity or by controlling when and where the molecules are allowed to interact. This spatial and temporal control mechanism is mediated by a family of specialised molecules, called 14-3-3 proteins. Recent research indicates that the function of these 14-3-3 proteins is also tightly controlled, although as yet we don't understand how. This research proposal attempts to discover the molecular mechanism of regulation of 14-3-3 function. An understanding of this process may provide new molecular targets for the development of therapeutics against cancer.Read moreRead less