Biology subjects

Stoll, T.

Publications and source records attributed to Stoll, T..

3 recordsLinked to original sources

bioRxiv2023

Imetelstat-Mediated Alterations in Fatty Acid Metabolism To Induce Ferroptosis As Therapeutic Strategy for Acute Myeloid Leukemia

Telomerase enables replicative immortality in most cancers including acute myeloid leukemia (AML). Imetelstat is a first-in-class telomerase inhibitor with clinical efficacy in myelofibrosis and myelodysplastic syndromes. Here, we develop an AML patient-derived xenograft (PDX) resource, and perform integrated genomics, transcriptomics, and lipidomics analyses combined with functional genetics to identify key mediators of imetelstat efficacy. In a randomized Phase II-like preclinical trial in PDX, imetelstat effectively diminishes AML burden, and preferentially targets subgroups containing mutant NRAS and oxidative stress-associated gene expression signatures. Unbiased, genome-wide CRISPR/Cas9 editing identifies ferroptosis regulators as key mediators of imetelstat efficacy. Imetelstat promotes the formation of polyunsaturated fatty acid-containing phospholipids, causing excessive levels of lipid peroxidation and oxidative stress. Pharmacological inhibition of ferroptosis diminishes imetelstat efficacy. We leverage these mechanistic insights to develop an optimized therapeutic strategy using oxidative stress-inducing chemotherapy to sensitize patient samples to imetelstat causing significant disease control in AML.

cancer biology↗

bioRxiv2021

Systemic host inflammation induces stage-specific transcriptomic modification and slower maturation in malaria parasites

Maturation rate of malaria parasites within red blood cells (RBC) can be influenced by host nutrient status or circadian rhythm. Here, we observed in mice that systemic host inflammation, induced by lipopolysaccharide (LPS) conditioning or ongoing acute malaria infection, slowed the progression of a single cohort of parasites from one generation of RBC to the next. LPS-conditioning and acute infection both triggered substantial changes to the metabolomic composition of plasma in which parasites circulated. This altered plasma directly slowed parasite maturation in a manner that could not be rescued by supplementation, consistent with the presence of inhibitory factors. Single-cell transcriptomic assessment of mixed parasite populations, exposed to a short period of systemic host inflammation in vivo, revealed specific impairment in the transcriptional activity and translational capacity of trophozoites compared to rings or schizonts. Thus, we provide in vivo evidence of transcriptomic and phenotypic plasticity of asexual blood-stage Plasmodium parasites when exposed to systemic host inflammation.

microbiology↗

bioRxiv2019

Concurrent lipidomics and proteomics on malignant plasma cells from multiple myeloma patients: Probing the lipid metabolome

BackgroundMultiple myeloma (MM) is a hematological malignancy characterized by the clonal expansion of malignant plasma cells. Though durable remissions are possible, MM is considered incurable, with relapse occurring in almost all patients. There has been limited data reported on the lipid metabolism changes in plasma cells during MM progression. Here, we evaluated the feasibility of concurrent lipidomics and proteomics analyses from patient plasma cells, and report these data on a limited number of patient samples, demonstrating the feasibility of the method, and establishing hypotheses to be evaluated in the future. MethodsPlasma cells were purified from fresh bone marrow aspirates using CD138 microbeads. Proteins and lipids were extracted using a bi-phasic solvent system with methanol, methyl tert-butyl ether, and water. Untargeted proteomics, untargeted and targeted lipidomics were performed on 7 patient samples using liquid chromatography-mass spectrometry. Two comparisons were conducted: high versus low risk; relapse versus newly diagnosed. Proteins and pathways enriched in the relapsed group was compared to a public transcriptomic dataset from Multiple Myeloma Research Consortium reference collection (n=222) at gene and pathways level. ResultsFrom one million purified plasma cells, we were able to extract material and complete untargeted ([~]6000 and [~]3600 features in positive and negative mode respectively) and targeted lipidomics (313 lipids), as well as untargeted proteomics analysis ([~]4100 reviewed proteins). Comparative analyses revealed limited differences between high and low risk groups (according to the standard clinical criteria), hence we focused on drawing comparisons between the relapsed and newly diagnosed patients. Untargeted and targeted lipidomics indicated significant down-regulation of phosphatidylcholines (PCs) in relapsed MM. Although there was limited overlap of the differential proteins/transcripts, 76 significantly enriched pathways in relapsed MM were common between proteomics and transcriptomics data. Further evaluation of transcriptomics data for lipid metabolism network revealed enriched correlation of PC, ceramide, cardiolipin, arachidonic acid and cholesterol metabolism pathways to be exclusively correlated among relapsed but not in newly-diagnosed patients. ConclusionsThis study establishes the feasibility and workflow to conduct integrated lipidomics and proteomics analyses on patient-derived plasma cells. Potential lipid metabolism changes associated with MM relapse warrant further investigation.

systems biology↗