THE REGULATORY MECHANISM OF HAEM OXYGENASE PROTECTION AGAINST PHOTOIMMUNOSUPPRESSION AND SKIN CANCER
Funder
National Health and Medical Research Council
Funding Amount
$439,500.00
Summary
Current dogma holds that UVA radiation adds to UVB damage in the skin. However we have identified a window of UVA doses, easily achievable from daytime sunlight exposure, that do not cause sunburn and are not immunosuppressive, but that significantly attenuate the damaging effects of UVB. In mice the mechanism partially depends on the UVA-upregulated cytokine interferon-gamma, and strongly on the UVA-inducible antioxidant enzyme haem oxygenase-1 (HO-1). This project aims to establish how the HO- ....Current dogma holds that UVA radiation adds to UVB damage in the skin. However we have identified a window of UVA doses, easily achievable from daytime sunlight exposure, that do not cause sunburn and are not immunosuppressive, but that significantly attenuate the damaging effects of UVB. In mice the mechanism partially depends on the UVA-upregulated cytokine interferon-gamma, and strongly on the UVA-inducible antioxidant enzyme haem oxygenase-1 (HO-1). This project aims to establish how the HO-1 gene is regulated by UVA. Available data from cultured human skin cells suggest that HO-1 is UVA-inducible in fibroblasts but not keratinocytes, whereas we found both cell types respond in mouse skin, keratinocytes most actively. We will ascertain whether a species difference, or an anomaly in cultured cells, underlies these discrepancies. With human skin grafted onto immunodeficient SCID mice, we will study impaired immune function, an important prerequisite for cancer, compared with mouse skin in vivo. Using molecular biology techniques with this model, we will monitor the activity of the transcription factor Bach 1, known to bind to the DNA of the HO-1 promoter region to repress the gene normally, but reversibly by haem-binding, and the corresponding activity of HO-1, during immunoprotective (UVA exposure, haem elevated) conditions. Immunoprotection may result from binding by Bach 1 of haem released from microsomal proteins by UVA, its release from DNA and thus derepression of HO-1. We will seek evidence of a role for skin cytokines in modifying Bach 1 binding, and for Bach 1 and HO-1 actions during photocarcinogenesis induction with chronic UV exposure. The significance of the outcome of the studies will be in understanding how a natural ameliorating pathway induced by UVA radiation could be utilised for superior photoprotection strategies for skin cancer susceptible humans.Read moreRead less
Validation Of Stat3 As A Therapeutic Target In Diseases Arising From Its Inappropriate Activation By Gp130 Cytokines
Funder
National Health and Medical Research Council
Funding Amount
$674,142.00
Summary
Stomach cancer is the third most prevalent cancer in the Western World and result in the yearly death of several thousand people in Australia alone. We have discovered a specifice gene mutation of a receptor molecule called gp130 that results in the formation of stomach cancer in mice. We are now aiming to understand the exact molecular events by which this mutation results in the uncontrolled growth of stomach lining cells. We will employ a number of strategies to establish molecularly the exte ....Stomach cancer is the third most prevalent cancer in the Western World and result in the yearly death of several thousand people in Australia alone. We have discovered a specifice gene mutation of a receptor molecule called gp130 that results in the formation of stomach cancer in mice. We are now aiming to understand the exact molecular events by which this mutation results in the uncontrolled growth of stomach lining cells. We will employ a number of strategies to establish molecularly the extent to which this mouse model is informative for gastric cancer inhuman. In aprticular we will identify the genes that are involved in the progression of the disease. One important focus of the project is to see whether or not the moelcule (called Stat3) whose aberrant activation triggers the disease in the mouse could provide a future pharmacological target for intervention with the disease. Similarly with expertise of CIB, we will investigate with novel proteomics techniques whther we can identify a protein in the serum of these mice, which could give us aclue of whether or not the mouse ahs already developed disease. Such a protein could be of potentail diagnostic importance in the future to screen human for gastric cancer which in its eraly stages is usually without any clinical symptoms. In a related Aim we will find out the gene that can genetically cooperate with Stat3 and that is required to enable survival of newborn mice. It may well turn out mOur proposal combines the expertise of the two investigators in signal transduction and that this gene may be an important determinant to ensure that Stat3 triggers physiological rather than pathological responses in many differnet organs.Read moreRead less
MODULATING MIC-1 CYTOKINE BIOAVAILABILITY: IMPACT ON TUMOUR BIOLOGY
Funder
National Health and Medical Research Council
Funding Amount
$341,210.00
Summary
MIC-1 cytokine is secreted by many tumour cells. It is commonly secreted as an inactive precursor form of MIC-1 which binds to the extracellular matrix surrounding cells, via its propeptide. This creates latent stores of cytokine which can be released and activated under specific conditions. The propeptide controls the balance between latent stores of inactive MIC-1 precursor and soluble forms of mature bioactive cytokine, which can act on surrounding cells or move into the circulation. The sign ....MIC-1 cytokine is secreted by many tumour cells. It is commonly secreted as an inactive precursor form of MIC-1 which binds to the extracellular matrix surrounding cells, via its propeptide. This creates latent stores of cytokine which can be released and activated under specific conditions. The propeptide controls the balance between latent stores of inactive MIC-1 precursor and soluble forms of mature bioactive cytokine, which can act on surrounding cells or move into the circulation. The significance of these latent stores is underscored by the finding that the level of these stores correlates with prostate cancer outcome, and also that very high circulating levels of active MIC-1 cytokine in the blood, leads to the massive weight loss characteristic of a syndrome called cancer cachexia. This is common in late stages of cancer and is a major contributing factor to the death of cancer patients. Understanding the mechanisms by which latent MIC-1 stromal stores are created and regulated, as well as their role in tumourigenesis, will have major impact on our understanding of the role of this cytokine in cancer. This is essential in order to adequately harness that knowledge for the benefit of patients.Read moreRead less
Role Of SOCS3 In Mammary Gland Development And Tumorigenesis
Funder
National Health and Medical Research Council
Funding Amount
$224,278.00
Summary
We are studying the role of a family of inhibitory molecules (SOCS) in breast tissue; these proteins have been established to have critical roles in the immune system and in regulating growth of the entire animal. We have demonstrated that one member of this family can block the action of the prolactin hormone and have recently obtained evidence that another member of this family, SOCS3, affects survival of breast cells. Furthermore, this protein leads to increased growth when overexpressed in b ....We are studying the role of a family of inhibitory molecules (SOCS) in breast tissue; these proteins have been established to have critical roles in the immune system and in regulating growth of the entire animal. We have demonstrated that one member of this family can block the action of the prolactin hormone and have recently obtained evidence that another member of this family, SOCS3, affects survival of breast cells. Furthermore, this protein leads to increased growth when overexpressed in breast cells. We propose to define the normal role of this gene in mouse mammary tissue and to examine the consequences of expressing the gene at high levels in the mammary glands of mice. Inappropriate expression of this gene may predispose humans to breast cancer. SOCS3 expression will be directly studied in a cohort of primary invasive breast cancers with associated clinical outcome data, to determine whether it has a role as a potential prognostic marker.Read moreRead less