Sir Peter MacCallum Department of Oncology - Research Publications
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ItemTargeting mTOR-dependent with specific inhibitors: a model for personalized medicine based on molecular diagnoses(MULTIMED INC, 2009-02-01)Cancer cells are characterized by aberrant growth arising from deregulated signalling pathways. The mammalian target of rapamycin (mTOR) pathway integrates multiple growth signals coming from both intracellular and extracellular cues. In this short review, we summarize what is known about the efficacy of targeting the mTOR pathway to treat cancer patients, and we explain the rationale behind promising new inhibitors that could show more potent tumour growth inhibition than did the first generation of these drugs.
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ItemDifferential expression of selected histone modifier genes in human solid cancers(BMC, 2006-04-25)BACKGROUND: Post-translational modification of histones resulting in chromatin remodelling plays a key role in the regulation of gene expression. Here we report characteristic patterns of expression of 12 members of 3 classes of chromatin modifier genes in 6 different cancer types: histone acetyltransferases (HATs)- EP300, CREBBP, and PCAF; histone deacetylases (HDACs)- HDAC1, HDAC2, HDAC4, HDAC5, HDAC7A, and SIRT1; and histone methyltransferases (HMTs)- SUV39H1and SUV39H2. Expression of each gene in 225 samples (135 primary tumours, 47 cancer cell lines, and 43 normal tissues) was analysedby QRT-PCR, normalized with 8 housekeeping genes, and given as a ratio by comparison with a universal reference RNA. RESULTS: This involved a total of 13,000 PCR assays allowing for rigorous analysis by fitting a linear regression model to the data. Mutation analysis of HDAC1, HDAC2, SUV39H1, and SUV39H2 revealed only two out of 181 cancer samples (both cell lines) with significant coding-sequence alterations. Supervised analysis and Independent Component Analysis showed that expression of many of these genes was able to discriminate tumour samples from their normal counterparts. Clustering based on the normalized expression ratios of the 12 genes also showed that most samples were grouped according to tissue type. Using a linear discriminant classifier and internal cross-validation revealed that with as few as 5 of the 12 genes, SIRT1, CREBBP, HDAC7A, HDAC5 and PCAF, most samples were correctly assigned. CONCLUSION: The expression patterns of HATs, HDACs, and HMTs suggest these genes are important in neoplastic transformation and have characteristic patterns of expression depending on tissue of origin, with implications for potential clinical application.
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ItemCbl associates with Pyk2 and Src to regulate Src kinase activity, alpha(v)beta(3) integrin-mediated signaling, cell adhesion, and osteoclast motility(ROCKEFELLER UNIV PRESS, 2001-01-08)The signaling events downstream of integrins that regulate cell attachment and motility are only partially understood. Using osteoclasts and transfected 293 cells, we find that a molecular complex comprising Src, Pyk2, and Cbl functions to regulate cell adhesion and motility. The activation of integrin alpha(v)beta(3) induces the [Ca(2+)](i)-dependent phosphorylation of Pyk2 Y402, its association with Src SH2, Src activation, and the Src SH3-dependent recruitment and phosphorylation of c-Cbl. Furthermore, the PTB domain of Cbl is shown to bind to phosphorylated Tyr-416 in the activation loop of Src, the autophosphorylation site of Src, inhibiting Src kinase activity and integrin-mediated adhesion. Finally, we show that deletion of c Src or c-Cbl leads to a decrease in osteoclast migration. Thus, binding of alpha(v)beta(3) integrin induces the formation of a Pyk2/Src/Cbl complex in which Cbl is a key regulator of Src kinase activity and of cell adhesion and migration. These findings may explain the osteopetrotic phenotype in the Src(-/-) mice.
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ItemA mouse with a loss-of-function mutation in the c-Cbl TKB domain shows perturbed thymocyte signaling without enhancing the activity of the ZAP-70 tyrosine kinase(ROCKEFELLER UNIV PRESS, 2003-02-17)The unique tyrosine kinase binding (TKB) domain of Cbl targets phosphorylated tyrosines on activated protein tyrosine kinases (PTKs); this targeting is considered essential for Cbl proteins to negatively regulate PTKs. Here, a loss-of-function mutation (G304E) in the c-Cbl TKB domain, first identified in Caenorhabditis elegans, was introduced into a mouse and its effects in thymocytes and T cells were studied. In marked contrast to the c-Cbl knockout mouse, we found no evidence of enhanced activity of the ZAP-70 PTK in thymocytes from the TKB domain mutant mouse. This finding contradicts the accepted mechanism of c-Cbl-mediated negative regulation, which requires TKB domain targeting of phosphotyrosine 292 in ZAP-70. However, the TKB domain mutant mouse does show aspects of enhanced signaling that parallel those of the c-Cbl knockout mouse, but these involve the constitutive activation of Rac and not enhanced PTK activity. Furthermore, the enhanced signaling in CD4(+)CD8(+) double positive thymocytes appears to be compensated by the selective down-regulation of CD3 on mature thymocytes and peripheral T cells from both strains of mutant c-Cbl mice.
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ItemKoilocytes indicate a role for human papilloma virus in breast cancer.(Springer Science and Business Media LLC, 2009-10-20)BACKGROUND: High-risk human papilloma viruses (HPVs) are candidates as causal viruses in breast cancer. The scientific challenge is to determine whether HPVs are causal and not merely passengers or parasites. Studies of HPV-related koilocytes in breast cancer offer an opportunity to address this crucial issue. Koilocytes are epithelial cells characterised by perinuclear haloes surrounding condensed nuclei and are commonly present in cervical intraepithelial neoplasia. Koilocytosis is accepted as pathognomonic (characteristic of a particular disease) of HPV infection. The aim of this investigation is to determine whether putative koilocytes in normal and malignant breast tissues are because of HPV infection. METHODS: Archival formalin-fixed normal and malignant breast specimens were investigated by histology, in situ PCR with confirmation of the findings by standard PCR and sequencing of the products, plus immunohistochemistry to identify HPV E6 oncoproteins. RESULTS: human papilloma virus-associated koilocytes were present in normal breast skin and lobules and in the breast skin and cancer tissue of patients with ductal carcinoma in situ (DCIS) and invasive ductal carcinomas (IDCs). INTERPRETATION: As koilocytes are known to be the precursors of some HPV-associated cervical cancer, it follows that HPVs may be causally associated with breast cancer.
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ItemHuman papilloma virus is associated with breast cancer.(Springer Science and Business Media LLC, 2009-10-20)BACKGROUND: There is increasing evidence that high-risk human papilloma virus (HPV) is involved in cancers in addition to cervical cancer. For example, it is generally accepted that HPV has a role in a significant proportion of head and neck tumours, and it has long been hypothesised that hormone dependent oncogenic viruses, such as HPV may have causal roles in some human breast cancers. A number of reports have identified HPV DNA in breast tissue and breast cancer specimens, but these rely on standard polymerase chain reaction (PCR), which is criticised for its propensity for contamination. METHODS: We have used two different technologies, in situ and standard PCR (with sequencing), and histology based on light microscopy. RESULTS: We unambiguously demonstrate the presence of high-risk HPV in the cells of breast cancer specimens and breast cancer cell lines. In addition, we also show that the oncogenic characteristics of HPV associated breast cancer are very similar to HPV-associated cervical cancer. Specifically, that putative koilocytes are present in some HPV associated breast cancers. INTERPRETATION: The above observations indicate a likely causal role for high-risk HPV in human breast cancer and offer the possibility of primary prevention of some breast cancers by vaccination against HPV.
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ItemUnproven medical devices and cancer therapy: big claims but no evidence.(Department of Biomedical Imaging, University of Malaya, Malaysia, 2008-07)
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ItemConformal radiotherapy and molecular imaging: complementary technologies in cancer therapy.(Department of Biomedical Imaging, University of Malaya, Malaysia, 2006-01)
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ItemActive surveillance for candidemia, Australia(CENTERS DISEASE CONTROL & PREVENTION, 2006-10-01)Population-based surveillance for candidemia in Australia from 2001 to 2004 identified 1,095 cases. Annual overall and hospital-specific incidences were 1.81/100,000 and 0.21/1,000 separations (completed admissions), respectively. Predisposing factors included malignancy (32.1%), indwelling vascular catheters (72.6%), use of antimicrobial agents (77%), and surgery (37.1%). Of 919 episodes, 81.5% were inpatient healthcare associated (IHCA), 11.6% were outpatient healthcare associated (OHCA), and 6.9% were community acquired (CA). Concomitant illnesses and risk factors were similar in IHCA and OHCA candidemia. IHCA candidemia was associated with sepsis at diagnosis (p<0.001), death <30 days after infection (p<0.001), and prolonged hospital admission (p<0.001). Non-Candida albicans species (52.7%) caused 60.5% of cases acquired outside hospitals and 49.9% of IHCA candidemia (p = 0.02). The 30-day death rate was 27.7% in those > or =65 years of age. Adult critical care stay, sepsis syndrome, and corticosteroid therapy were associated with the greatest risk for death. Systematic epidemiologic studies that use standardized definitions for IHCA, OHCA, and CA candidemia are indicated.
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ItemA randomized controlled trial of an exercise intervention targeting cardiovascular and metabolic risk factors for prostate cancer patients from the RADAR trial(BMC, 2009-12-02)BACKGROUND: Androgen deprivation therapy leads to a number of adverse effects including deterioration of the musculoskeletal system and increased risk factors for cardiovascular and metabolic complications. The purpose of this study is to determine the effects, efficacy, retention and compliance of a physical exercise intervention in a large established cohort of prostate cancer patients from the Randomised Androgen Deprivation and Radiotherapy (RADAR) study. Specifically, we aim to compare short- and long-term effects of a prostate cancer-specific supervised exercise program to a standard public health physical activity strategy utilizing printed resources on cardiovascular and metabolic risk factors. Our primary outcomes are cardiorespiratory capacity, abdominal obesity, and lipid and glycemic control, while secondary outcomes include self-reported physical activity, quality of life and psychological distress. METHODS/DESIGN: Multi-site randomized controlled trial of 370 men from the RADAR study cohort undergoing treatment or previously treated for prostate cancer involving androgen deprivation therapy in the cities of Perth and Newcastle (Australia), and Wellington (New Zealand). Participants will be randomized to (1) supervised resistance/aerobic exercise or (2) printed material comprising general physical activity recommendations. Participants will then undergo progressive training for 6 months. Measurements for primary and secondary endpoints will take place at baseline, 6 months (end of intervention), and at 6 months follow-up. DISCUSSION: This study uses a large existent cohort of patients and will generate valuable information as to the continuing effects of exercise specifically targeting cardiovascular function and disease risk, insulin metabolism, abdominal obesity, physical function, quality of life and psychological distress. We expect dissemination of the knowledge gained from this project to reduce risk factors for the development of co-morbid diseases commonly associated with androgen deprivation therapy such as cardiovascular disease, obesity, metabolic disease and diabetes, as well as improvements in physical and functional ability, and quality of life. TRIAL REGISTRATION: ACTRN12609000729224.