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
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
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
Studies On New Mononuclear And Polynuclear Platinum Compounds With Trans-geometry
Funder
National Health and Medical Research Council
Funding Amount
$68,617.00
Summary
Even in post-genomic age cisplatin continues to be widely used as a highly successful anticancer drug. However, the drug has a number of side effects and does not show activity against many types of cancer. in some cases, resistant form of cancer develops for which the drug does not function. An example is ovarian cancer. This project aims to arrive at new platinum-based anticancer drugs targeted to ovarian cancer.
How The Bcl-2 Protein Family Controls Apoptosis And Impacts On Cancer Development And Therapy
Funder
National Health and Medical Research Council
Funding Amount
$850,346.00
Summary
Impaired cell death (apoptosis) is now recognized as an important step towards cancer and a major barrier to effective therapy. The discoveries on apoptosis by Professor Jerry Adams and colleagues have galvanized the search for drugs that engage the cell’s apoptotic machinery as a new way to treat cancer. His proposed studies aim to clarify how apoptosis is controlled and how the control goes awry in cancer, and to determine how such drugs can be most effectively used to improve cancer treatment ....Impaired cell death (apoptosis) is now recognized as an important step towards cancer and a major barrier to effective therapy. The discoveries on apoptosis by Professor Jerry Adams and colleagues have galvanized the search for drugs that engage the cell’s apoptotic machinery as a new way to treat cancer. His proposed studies aim to clarify how apoptosis is controlled and how the control goes awry in cancer, and to determine how such drugs can be most effectively used to improve cancer treatment.Read moreRead less
Targeting 124I To The DNA Of Tumours For PET Imaging And Auger-Radiotherapy
Funder
National Health and Medical Research Council
Funding Amount
$787,000.00
Summary
The aim of this project is to develop a new method of targeting radioactivity to tumours, for detection and treatment, using a radioactive element (iodine-124). Iodine-124 emits a form of radiation called positrons, detected by a new imaging technique - Positron Emission Tomography (PET). Therefore, tumours labelled with iodine-124 can be imaged by PET. Also, iodine-124 is amongst a class of radioactive atoms (called Auger-emitters) that emit a shower of very low energy electrons. This intense f ....The aim of this project is to develop a new method of targeting radioactivity to tumours, for detection and treatment, using a radioactive element (iodine-124). Iodine-124 emits a form of radiation called positrons, detected by a new imaging technique - Positron Emission Tomography (PET). Therefore, tumours labelled with iodine-124 can be imaged by PET. Also, iodine-124 is amongst a class of radioactive atoms (called Auger-emitters) that emit a shower of very low energy electrons. This intense focus of radiation damage, can be exploited to kill cancer cells by inflicting lethal DNA damage. To bring the iodine-124 close to the DNA molecule, we will attach it to a DNA-binding drug linked to a tumour-seeking protein, such as an anti-tumour antibody. After injection of the radioactive drug-protein cocktail, PET imaging will be used to assess the extent of tumour targeting, to enable calculation of the amount of cocktail required for successful tumour treatment by further injections. There are some situations where tumour imaging needs to be non-damaging, such as in using PET imaging to assess the success of surgical removal of a tumour. Therefore, we will design an alternative version of the iodine-124-labelled DNA- binding drug with the radioactive atom in a location that will minimise DNA damage from radioactive decay. In this imaging-only scenario, the Auger-emission feature is suppressed whilst still exploiting positron-emission for imaging. The stability of radioactive atoms varies widely, and the half-life of iodine-124 (about four days) is an ideal compromise for imaging and treatment. By contrast, the utility of the most commonly used isotope for PET imaging, fluorine-18, is limited by its half-life of only a few hours. The PET Centre at PeterMac will soon produce iodine-124, joining one of only a few centres throughout the world. Peter Mac has recently lodged a patent application for the technology to be developed in this project.Read moreRead less
Engineered Histones As DNA Carriers With Application In Therapeutic Gene Delivery
Funder
National Health and Medical Research Council
Funding Amount
$417,750.00
Summary
We intend to apply our knowledge of protein transport to the nucleus to enhance the delivery of DNA to target cells. This relates to the use of gene therapy to treat genetic defects such as inborn errors of metabolism, where a disease-causing lack-of-function mutation can be overcome by engineering cells within the organism which express, in the necessary quantities and in response to the appropriate regulatory signals, the particular component which is lacking. A limiting factor in gene therapy ....We intend to apply our knowledge of protein transport to the nucleus to enhance the delivery of DNA to target cells. This relates to the use of gene therapy to treat genetic defects such as inborn errors of metabolism, where a disease-causing lack-of-function mutation can be overcome by engineering cells within the organism which express, in the necessary quantities and in response to the appropriate regulatory signals, the particular component which is lacking. A limiting factor in gene therapy approaches is the low efficiency of nuclear uptake of introduced DNA, where it has been estimated that < 1% of the DNA taken up is actually expressed. Our proposal seeks to develop approaches to enhance non-viral-mediated gene delivery, in particular by optimising this critical, limiting step of the delivery of exogenous DNA to the nucleus. We intend to apply knowledge from studies of nuclear targeting and chromatin assembly to improve gene transfer technologies. We will build on our work showing that specific signals for nuclear import - nuclear targeting signals (NTSs) - can be used to enhance nuclear gene delivery and expression. Since DNA in the normal cellular context is in the form of chromatin - a specific complex with proteins such as histones - we intend to use reconstituted chromatin as the transfecting DNA, whereby histones engineered to include NTSs and other modular sequence elements will be used. Chromatin should not only enable NTSs and other sequence modules to be linked to the DNA but also protect against nuclease-mediated degradation prior to nuclear entry, condense the DNA to enable more efficient cellular-nuclear entry, and ensure expression of the transfected reporter gene by presenting it to the cell in a physiological context. Our approaches should contribute to bringing gene therapy closer to reality in the clinic.Read moreRead less
Targeting Nucleic Acid Synthesis And Cell Division In Gram-negative Bacterial Pathogens
Funder
National Health and Medical Research Council
Funding Amount
$966,800.00
Summary
Some bacteria like Acinetobacter species cause infections in hospitals that are difficult to treat because they have acquired resistance to most antibiotics. This project will combine the complementary expertise of five research groups to develop knowledge of, and how to block, three essential processes in these worrying pathogenic species: copying of DNA, RNA synthesis, and cell division. This promises to lead to development of new antibacterial therapies.