Biology subjects

Chalmers, A. J.

Publications and source records attributed to Chalmers, A. J..

3 recordsLinked to original sources

bioRxiv2021

Increased apoptotic priming of glioblastoma enables therapeutic targeting by BH3-mimetics

IDH wild-type glioblastoma (GBM) is the most prevalent malignant primary brain tumour in adults. GBM typically has a poor prognosis, mainly due to a lack of effective treatment options leading to tumour persistence or recurrence. Tackling this, we investigated the therapeutic potential of targeting anti-apoptotic BCL-2 proteins in GBM. Levels of anti- apoptotic BCL-xL and MCL-1 were consistently increased in GBM compared with non- malignant cells and tissue. Moreover, we found that relative to their differentiated counterparts, patient-derived GBM stem-like cells also displayed higher expression of anti- apoptotic BCL-2 family members. Surprisingly, high anti-apoptotic BCL-xL and MCL-1 expression correlated with heightened susceptibility of GBM to BCL-2 family protein- targeting BH3-mimetics. This is indicative of increased apoptotic priming. Indeed, GBM displayed an obligate requirement for MCL-1 expression in both tumour development and maintenance. Investigating this apoptotic sensitivity, we found that sequential inhibition of BCL-xL and MCL-1 led to robust anti-tumour responses in vivo, in the absence of overt toxicity. These data demonstrate that BCL-xL and MCL-1 pro-survival function is a fundamental prerequisite for GBM survival that can be therapeutically exploited by BH3- mimetics.

cancer biology↗

bioRxiv2021

Low-dose lung radiotherapy for COVID-19 lung disease: a pre-clinical efficacy study in a bleomycin model of pneumonitis.

PurposeLow-dose whole lung radiotherapy (LDLR) has been proposed as a treatment for patients with acute respiratory distress syndrome associated with SARS-CoV-2 infection and clinical trials are underway. There is an urgent need for preclinical evidence to justify this approach and inform dose, scheduling and mechanisms of action. Materials and methodsFemale C57BL/6 mice were treated with intranasal bleomycin sulphate (7.5 or 11.25 units/kg, day 0), then exposed to whole lung radiation therapy (0.5, 1.0, 1.5 Gy or sham, day 3). Bodyweight was measured daily and lung tissue harvested for histology and flow cytometry on day 10. Computed tomography (CT) lung imaging was performed pre-radiation (day 3) and pre-endpoint (day 10). ResultsBleomycin caused pneumonitis of variable severity which correlated with weight loss. LDLR at 1.0 Gy was associated with a significant increase in the proportion of mice recovering to 98% of initial bodyweight and a proportion of these mice exhibited less severe histopathological lung changes. Mice experiencing moderate initial weight loss were more likely to respond to LDLR than those experiencing severe initial weight loss. Additionally, LDLR (1.0 Gy) significantly reduced bleomycin-induced increases in interstitial macrophages, CD103+ dendritic cells and neutrophil-DC hybrids. Overall,bleomycin-treated mice exhibited significantly higher percentages of non-aerated lung in left than right lungs and LDLR (1.0 Gy) prevented further reductions in aerated lung volume in right but not left lungs. LDLR at 0.5 and 1.5 Gy did not modulate bodyweight or flow cytometric readouts of bleomycin-induced pneumonitis. ConclusionsOur data support the concept that LDLR can ameliorate acute inflammatory lung injury, identify 1.0 Gy as the most effective dose and provide preliminary evidence that it is more effective in the context of moderate than severe pneumonitis. Mechanistically, LDLR at 1.0 Gy significantly suppressed bleomycin-induced accumulation of pulmonary interstitial macrophages, CD103+ dendritic cells and neutrophil-DC hybrids.

immunology↗

bioRxiv2020

Quantitative in vivo bioluminescence imaging of orthotopic patient-derived glioblastoma xenografts

Despite extensive research, little progress has been made in glioblastoma therapy, owing in part to a lack of adequate preclinical in vivo models to study this disease. To mitigate this, primary patient-derived cell lines, which maintain their specific stem-like phenotypes, have replaced established glioblastoma cell lines. However, due to heterogenous tumour growth inherent in glioblastoma, the use of primary cells for orthotopic in vivo studies often requires large experimental group sizes. Therefore, when using intracranial patient-derived xenograft (PDX) approaches, it is advantageous to deploy imaging techniques to monitor tumour growth and allow stratification of mice. Here we show that stable expression of near-infrared fluorescent protein (iRFP) in patient-derived glioblastoma cells enables rapid direct non-invasive monitoring of tumour development without compromising tumour stemness or tumorigenicity. Moreover, as this approach does not depend on the use of agents like luciferin, which can cause variability due to changing bioavailability, it can be used for quantitative longitudinal monitoring of tumour growth. Notably, we show that this technique also allows quantitative assessment of tumour burden in highly invasive models spreading throughout the brain. Thus, iRFP transduction of primary patient-derived glioblastoma cells is a reliable, cost- and time-effective way to monitor heterogenous orthotopic PDX growth.

cancer biology↗