Search

Abstract: Background: Technology has progressed from single gene panel to large‐scale genomic sequencing. This is raising expectations from clinicians and patients alike. The utility and performance of this technology in a clinical setting needs to be evaluated. Aim: This pilot study investigated the feasibility of using exome‐scale sequencing (ESS) to identify molecular drivers within cancers in real‐time for Precision Oncology in the clinic. Methods: Between March 2014 and March 2015, the Victorian Comprehensive Cancer Centre Alliance explored the feasibility and utility of ESS in a pilot study. DNA extracted from the tumour specimens underwent both ESS and targeted ‘hotspot’ sequencing (TS). Blood was taken for germline analysis. A multi‐disciplinary molecular tumour board determined the clinical relevance of identified mutations; in particular, whether they were ‘actionable’ and/or ‘druggable’. Results: Of 23 patients screened, 15 (65%) met the tissue requirements for genomic analysis. TS and ESS were successful in all cases. ESS identified pathogenic somatic variants in 73% (11/15 cases) versus 53% (8/15 cases) using TS. Clinically focused ESS identified 63 variants, consisting of 30 somatic variants (including all 13 identified by TS) and 33 germline variants. Overall, there were 48 unique variants. ESS had a clinical impact in 53% (8/15 cases); 47% (7/15 cases) were referred to the familial cancer clinic, and ‘druggable’ targets were identified in 53% (8/15 cases). Conclusion: ESS of tumour DNA impacted clinical decision‐making in 53%, with 20% more pathogenic variants identified through ESS than TS. The identification of germline variants in 47% was an unexpected finding. [ABSTRACT FROM AUTHOR]

Background It has long been established that cardiotoxicity occurs as a result of exposure to certain chemotherapeutics, particularly anthracyclines. Historically, clinicians equate cardiotoxicity with a poor prognosis, in a small percentage of patients and deem long-term surveillance as optional. Emerging evidence suggests that anthracycline cardiotoxicity ( ACT) is a life-long risk with an incidence approaching 20%. Aims To elucidate the incidence of anthracycline cardiotoxicity within a current paediatric oncology survivor cohort. Methods Participants were identified through the Haematology-Oncology database at the Royal Children's Hospital, Melbourne. Patients were identified from a retrospective audit of outpatient attendances between January 2008 and December 2015. Patients with a cancer diagnosis exposed to anthracyclines were eligible for the study. Patient demographics and echocardiogram findings were recorded with patients subcategorised according to degree of ACT. More significant ACT defined as fractional shortening ( FS) <24% and less significant if FS 24-28% or a decline in baseline ejection fraction of >10%. Results Two hundred and eighty-six of a total 481 identified patients were eligible for study inclusion. Twenty patients displayed significant ACT with FS <24%. Ten patients had a FS 24-28% and 25 patients with a decline in ejection fraction from baseline of >10%. Overall, 6.6% demonstrated significant cardiac complications, whilst 19.6 % demonstrated some degree of ACT and decline in myocardial function. When stratified for cumulative anthracycline dose, the incidence of severe cardiac dysfunction was 5.1% (<250 mg/m2) and 25% (>250 mg/m2) Conclusion This study demonstrates, in keeping with modern literature, the higher incidence of anthracycline associated cardiac toxicity and a need for better surveillance and follow up. [ABSTRACT FROM AUTHOR]

Cytokines are secreted soluble peptides that precisely regulate multiple cellular functions. Amongst these the GM-CSF/IL-3/IL-5 family of cytokines controls whether hematopoietic cells will survive or apoptose, proliferate, differentiate, migrate, or perform effector functions such as phagocytosis or reactive oxygen species release. Their potent and pleiotropic activities are mediated through binding to high affinity membrane receptors at surprisingly low numbers per cell. Receptor binding triggers a cascade of intracellular signaling events, including reversible phosphorylation of receptor subunits and associated signaling molecules, leading to multiple biological responses, with the prevention of apoptosis or “cell survival” being a key cellular function that underpins all others. Many chronic inflammatory diseases and a number of haematological malignancies are driven by deregulated GM-CSF, IL-3, or IL-5 cytokine receptor signaling, highlighting their importance in disease. A major step in understanding how these cytokine receptors function is to elucidate their three dimensional structure and to relate this to the many signaling pathways emanating from their receptors. We have recently solved the structure of the human GM-CSF receptor complexed to GM-CSF which revealed distinct forms of receptor assembly: a hexamer that comprises two molecules each of GM-CSF, GM-CSF receptor alpha chain and GM-CSF receptor beta chain; and an unexpected dodecamer in which two hexameric complexes associate through a novel site 4. This latter form is necessary to bring JAK2 molecules sufficiently close together to enable full receptor activation. In this review we focus on the most recent insights in cytokine receptor signaling, and in receptor assembly. The stage is now set to link distinct forms of cytokine receptor assembled structures to specific forms of cytokine receptor signaling and function. Armed with this knowledge it may be possible to map distinct cytokine receptor signaling pathways from the cell surface to the cell nucleus which may themselves become new therapeutic targets. © 2010 IUBMB IUBMB Life, 62(7): 509–518, 2010 [ABSTRACT FROM AUTHOR]

Caspases are a family of cysteine proteases with roles in cytokine maturation or apoptosis. Caspase-2 was the first pro-apoptotic caspase identified, but its functions in apoptotic signal transduction are still being elucidated. This study examined the regulation of the activity of caspase-2 using recombinant proteins and a yeast-based system. Our data suggest that for human caspase-2 to be active its large and small subunits must be separated. For maximal activity its prodomain must also be removed. Consistent with its proposed identity as an upstream caspase, caspase-2 could provoke the activation of caspase-7. Caspase-2 was not subject to inhibition by members of the IAP family of apoptosis inhibitors. [ABSTRACT FROM AUTHOR]

XIAP is a mammalian inhibitor of apoptosis protein (lAP). To determine residues within the second baculoviral lAP repeat (BIR2) required for inhibition of caspase 3, we screened a library of BIR2 mutants for toss of the ability to inhibit caspase 3 toxicity in the yeast Schizosaccharomyces pombe. Four of the mutations, not predicted to affect the structure of the BIR fold, clustered together on the N-terminal region that flanks BIR2, suggesting that this is a site of interaction with caspase 3. Introduction of these mutations into full-length XIAP reduced caspase 3 inhibitory activity up to 500-fold, but did not affect its ability to inhibit caspase 9 or interact with the lAP antagonist IMABLO. Furthermore, these mutants retained full ability to inhibit apoptosis in transfected cells, demonstrating that although XIAP is able to inhibit caspase 3, this activity is dispensable for inhibition of apoptosis by XIAP in vivo. [ABSTRACT FROM AUTHOR]

To study the role of various caspases during apoptosis, we have designed a series of caspase inhibitors based on the cowpox virus cytokine response modifier A (crmA) protein. Wild-type crmA inhibits caspases 1 and 8 and thereby protects cells from apoptosis triggered by ligation of CD95 or tumour necrosis factor (TNF) receptors, but it does not protect against death mediated by other caspases. By replacing the tetrapeptide pseudosubstrate region of crmA (LVAD) with tetrapeptides that are optimal substrates for the different families of caspases, or with the four residues from the cleavage site of the baculovirus protein p35 (DQMD), we have generated a family of caspase inhibitors that show altered ability to protect against cell death. Although DEVD is the optimal substrate for caspase 3, crmA DEVD was degraded rapidly and was a weaker inhibitor than crmA DQMD, which was not degraded. Unlike wild-type crmA and crmA DEVD, crmA DQMD was able to inhibit apoptosis caused by direct activation of caspase 3 and protected lymphoid cells from death induced by radiation and dexamethasone. Significantly, the protected cells were capable of sustained growth. [ABSTRACT FROM AUTHOR]

The article comments on a study which shows the possibility that genetic screening may reduce the rate of anthracycline toxicity. Topics discussed include the predictors of anthracycline toxicity such as genetic predisposing single nucleotide polymorphisms (SNPs) and biomarkers and the potential explanations for an apparent contribution to anthracycline cardiotoxicity such as RNA splicing.

The article offers information on the 11th Annual Congress of the Perinatal Society of Australia and New Zealand which will be held in Melbourne, Victoria on April 1-4, 2007.

Adrenal hypoplasia congenita (AHC) is a rare condition and causes primary adrenal insufficiency. X-linked (OMIM 300200) and autosomal recessive (OMIM 240200) forms are recognized. Recently, an association between Intrauterine growth restriction, Metaphyseal dysplasia, Adrenal hypoplasia congenita, and Genital abnormalities (IMAGe syndrome; OMIM 300290) has been described. We present the clinical features of two sisters with intrauterine growth restriction, AHC, and dysmorphic features. Interesting histopathologic findings of one sister are also presented. We suggest that IMAGe syndrome is the most plausible diagnosis and that autosomal recessive inheritance is likely. We analyzed genes that were postulated candidates for IMAGe syndrome (SF1, DAX-1, and STAR), and no mutations were found. Other cases of IMAGe syndrome are reviewed.