Medical Biology - Research Publications
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ItemTrajectory of immune evasion and cancer progression in hepatocellular carcinoma.(Nature Portfolio, 2022-03-17)Immune evasion is key to cancer initiation and later at metastasis, but its dynamics at intermediate stages, where potential therapeutic interventions could be applied, is undefined. Here we show, using multi-dimensional analyses of resected tumours, their adjacent non-tumour tissues and peripheral blood, that extensive immune remodelling takes place in patients with stage I to III hepatocellular carcinoma (HCC). We demonstrate the depletion of anti-tumoural immune subsets and accumulation of immunosuppressive or exhausted subsets along with reduced tumour infiltration of CD8 T cells peaking at stage II tumours. Corresponding transcriptomic modification occur in the genes related to antigen presentation, immune responses, and chemotaxis. The progressive immune evasion is validated in a murine model of HCC. Our results show evidence of ongoing tumour-immune co-evolution during HCC progression and offer insights into potential interventions to reverse, prevent or limit the progression of the disease.
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ItemLocation, location, location! Rewiring IL-2 circuits defines context-specific outcomes(WILEY, 2022-09)Here, we highlight a recent publication by Whyte et al. that reveals diverse immune outcomes of interleukin (IL)-2 expression in distinct microenvironments. Their definition of context-dependent IL-2 networks paves the way for the development of tissue-specific therapies that enlist the potent immuno-modulatory activity of IL-2.
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ItemThe BCL-2 family member BID plays a role during embryonic development in addition to its BH3-only protein function by acting in parallel to BAX, BAK and BOK(WILEY, 2022-08-01)The intrinsic apoptosis pathway, regulated by the BCL-2 protein family, is essential for embryonic development. Using mice lacking all known apoptosis effectors, BAX, BAK and BOK, we have previously defined the processes during development that require apoptosis. Rare Bok-/- Bax-/- Bak-/- triple knockout (TKO) mice developed to adulthood and several tissues that were thought to require apoptosis during development appeared normal. This raises the question if all apoptosis had been abolished in the TKO mice or if other BCL-2 family members could act as effectors of apoptosis. Here, we investigated the role of BID, generally considered to link the extrinsic and intrinsic apoptosis pathways, acting as a BH3-only protein initiating apoptosis upstream of BAX and BAK. We found that Bok-/- Bax-/- Bak-/- Bid-/- quadruple knockout (QKO) mice have additional developmental anomalies compared to TKO mice, consistent with a role of BID, not only upstream but also in parallel to BAX, BAK and BOK. Mitochondrial experiments identified a small cytochrome c-releasing activity of full-length BID. Collectively, these findings suggest a new effector role for BID in the intrinsic apoptosis pathway.
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ItemEditorial: lack of gastrointestinal symptoms caused by gluten in patients without coeliac disease-time to ditch the 'gluten' from 'non-coeliac gluten sensitivity'(WILEY, 2022-07)LINKED CONTENT This article is linked to Crawley et al papers. To view these articles, visit https://doi.org/10.1111/apt.16914 and https://doi.org/10.1111/apt.16980
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ItemEnhancing our chances of picking a winner in higher-risk myelodysplastic syndromes(WILEY, 2022-08)Hypomethylating agents remain the current standard of care for patients with higher-risk myelodysplastic syndromes. Adès et al. report outcomes from a randomised 'pick-a-winner' study design that examined the addition of either lenalidomide, valproic acid or idarubicin in combination with azacitidine, compared to azacitidine alone. Commentary on: Adès et al. A randomised phase II study of azacitidine (AZA) alone or with lenalidomide (LEN), valproic acid (VPA) or idarubicin (IDA) in higher-risk MDS: GFM's 'pick a winner' trial, with the impact of somatic mutations. Br J Haematol 2022;198:535-544.
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ItemRivaroxaban in the treatment of TEK-related venous malformation(WILEY, 2022-08)Low-flow vascular malformations are rare congenital anomalies due to errors in vascular development and may be associated with known pathogenic genetic variants. Slow flow through the blood vessels can lead to localized intralesional thromboses, which can cause debilitating pain and impair quality of life. We present a case of venous malformation due to a variant in the TEK gene in a 38-year-old woman in whom treatment with low dose rivaroxaban was successful in controlling symptoms of chronic localized intravascular coagulation.
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ItemImpact of the evolution in RAS mutation analysis in Australian patients with metastatic colorectal cancer(WILEY, 2022-10)BACKGROUND: RAS mutation testing now routinely informs the optimal management of metastatic colorectal cancer (mCRC), specifically the finding of a RAS mutation defines patients who will not benefit from treatment with an epidermal growth factor receptor inhibitor. Over time more RAS genes have been tested and more sensitive techniques used. AIMS: To review routine care RAS testing and results over time. METHODS: A retrospective analysis of the molecular data collected prospectively in the multi-site Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) registry from 2009 to 2018 was undertaken. Patients with RAS data were further analyzed. In parallel, the RAS mutation status of patients enrolled in the Test Tailor Treat (TTT) program was examined for 2011-2018. RESULTS: Of 2908 patients in the TRACC registry, 1892 (65%) were tested, with 898 (47%) of tested patients found to be RAS mutant (RASmt). RAS data were available for 5935 TTT patients. Of the tested TRACC patients diagnosed in 2009 and 2010, 38% were RASmt. For each 2-year period from 2011/2012 through to 2017/2018, the prevalence of RASmt in TRACC and TTT was 42% and 40% (2011/2012), 52% and 40% (2013/2014), 47% and 49% (2015/2016), and 47% and 49% (2017/2018). CONCLUSIONS: Based on both TRACC and TTT data, the proportion of patients reported to have a RAS mutation increased from 2009 to 2015 but has remained relatively stable in recent years. The increased proportion of RASmt patients observed over time is likely largely driven by the uptake of extended RAS testing.
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ItemUse and outcomes of chemotherapy for metastatic pancreatic cancer in Australia(WILEY, 2022-01)BACKGROUND: Metastatic pancreatic ductal adenocarcinoma (mPDAC) is highly lethal. Combination chemotherapy regimens improve overall survival (OS). Historically, only one-third of mPDAC patients in Victoria received chemotherapy. AIM: To describe current Australian chemotherapy utilisation and outcomes in patients with mPDAC using the multi-site PURPLE (Pancreatic cancer: Understanding Routine Practice and Lifting End Results) registry. METHODS: PURPLE collects longitudinal data on consecutive patients with pancreatic cancer seen since January 2016. Data were collated for patients with mPDAC from six Victorian sites, and analysed descriptively. RESULTS: Three hundred and sixty-three patients with mPDAC were identified. Median age was 70 years (range 20-94 years). First-line chemotherapy was administered in 195 (54%) patients. Prevalent regimens included gemcitabine-nab-paclitaxel (71%), gemcitabine alone (10%) and FOLFIRINOX (6%). Sixty-two of 195 (32%) patients who received first line treatment have proceeded to second-line chemotherapy. Chemotherapy-treated patients were younger (69 versus 73 years; P < 0.01), with better Eastern Cooperative Oncology Group (ECOG) performance status (ECOG 0-1 89 vs 66%; P < 0.01) and lower median Charlson comorbidity index (3 vs 4; P < 0.01) compared with untreated patients. Median OS of the entire cohort from diagnosis of metastases was 5.1 months. Median OS was 9.3 months in the chemotherapy treated patients, and 2.5 months in chemotherapy-untreated patients (P < 0.01). CONCLUSIONS: A substantial proportion of patients with mPDAC still do not receive active treatment, which may in part by explained by age, poor performance status and comorbidity. Gemcitabine-nab-paclitaxel was the preferred first-line chemotherapy regimen. Median OS for treated patients in this cohort was comparable to that of recent published clinical trials.
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ItemNecroptosis in chronic obstructive pulmonary disease, a smoking gun? COMMENT(WILEY, 2022-02)Recent studies, reviewed here, using a cigarette smoke exposure model for chronic obstructive pulmonary disease (COPD) in Ripk3 and Mlkl knock-out mice, and correlation with patient samples, suggest necroptosis plays a pathophysiological role in COPD by promoting inflammation, airway remodeling and emphysema.
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ItemCo-infection of the four major Plasmodium species: Effects on densities and gametocyte carriage(PUBLIC LIBRARY SCIENCE, 2022-09)BACKGROUND: Co-infection of the four major species of human malaria parasite Plasmodium falciparum (Pf), P. vivax (Pv), P. malariae (Pm), and P. ovale sp. (Po) is regularly observed, but there is limited understanding of between-species interactions. In particular, little is known about the effects of multiple Plasmodium species co-infections on gametocyte production. METHODS: We developed molecular assays for detecting asexual and gametocyte stages of Pf, Pv, Pm, and Po. This is the first description of molecular diagnostics for Pm and Po gametocytes. These assays were implemented in a unique epidemiological setting in Papua New Guinea with sympatric transmission of all four Plasmodium species permitting a comprehensive investigation of species interactions. FINDINGS: The observed frequency of Pf-Pv co-infection for asexual parasites (14.7%) was higher than expected from individual prevalence rates (23.8%Pf x 47.4%Pv = 11.3%). The observed frequency of co-infection with Pf and Pv gametocytes (4.6%) was higher than expected from individual prevalence rates (13.1%Pf x 28.2%Pv = 3.7%). The excess risk of co-infection was 1.38 (95% confidence interval (CI): 1.09, 1.67) for all parasites and 1.37 (95% CI: 0.95, 1.79) for gametocytes. This excess co-infection risk was partially attributable to malaria infections clustering in some villages. Pf-Pv-Pm triple infections were four times more frequent than expected by chance alone, which could not be fully explained by infections clustering in highly exposed individuals. The effect of co-infection on parasite density was analyzed by systematic comparison of all pairwise interactions. This revealed a significant 6.57-fold increase of Pm density when co-infected with Pf. Pm gametocytemia also increased with Pf co-infection. CONCLUSIONS: Heterogeneity in exposure to mosquitoes is a key epidemiological driver of Plasmodium co-infection. Among the four co-circulating parasites, Pm benefitted most from co-infection with other species. Beyond this, no general prevailing pattern of suppression or facilitation was identified in pairwise analysis of gametocytemia and parasitemia of the four species. TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov, Trial ID: NCT02143934.