Biology subjects

Tamburini, J.

Publications and source records attributed to Tamburini, J..

7 recordsLinked to original sources

bioRxiv2026

One-carbon metabolism sustains effector T cell function through cell-surface glycosylation

Folate is a driver of one-carbon metabolism that is essential in T cells. The cellular consequences of its deprivation in CD8+ T cells and impact on anti-tumor function are unknown. Single cell RNA-seq analysis of primary central nervous system lymphoma (PCNSL) patients' tumor samples revealed exhaustion in T cells with high folate metabolism gene expression signature. Functional genomics, metabolite profiling, and glycomics identified disrupted cell surface glycosylation as a major consequence of folate deprivation in CD8+ T cells. Mechanistically, folate deprivation reduced nucleotide sugar levels, perturbed glycosylation, and triggered the apoptotic unfolded protein response. Overexpressing folate transporters in adoptively transferred CD8+ T cells increased intratumoral T cell numbers and reduced exhaustion. Therefore, our data draw a mechanistic line between one-carbon metabolism, cell-surface glycosylation, and anti-tumor T cell function, and support a hypothesis that increased folate uptake can enhance CD8+ T cell function including ex vivo and in vivo CAR-T cells.

cell biology↗

bioRxiv2023

Ferritinophagy is a Druggable Vulnerability of Quiescent Leukemic Stem Cells

Acute myeloid leukemia (AML) remains a challenging hematological malignancy with poor prognosis and limited treatment options. Leukemic stem cells (LSCs) contributes to therapeutic failure, post-therapy relapse and adverse outcome. Here, we investigated the role of quiescence and its associated molecular mechanisms in AML pathogenesis and LSCs functions, and identified potential vulnerabilities for therapeutic intervention. We found that LSC-enriched quiescent cell population exhibited a distinct gene set of prognostic significance in AML patients. Furthermore, this quiescent cells subset displayed heightened autophagic activity with a reliance on ferritinophagy, a selective form of autophagy mediated by Nuclear Receptor Coactivator 4 (NCOA4) regulating iron bioavailability. Inhibition of NCOA4 genetically or chemically showed potent anti-leukemic effects, particularly targeting the LSC compartment. These findings uncover that ferritinophagy inhibition may represent a promising therapeutic strategy for patients with AML. One Sentence SummaryTargeting quiescent leukemic stem cells via NCOA4-dependent ferritinophagy inhibition may improve therapeutic outcomes in acute myeloid leukemia.

cancer biology↗

bioRxiv2023

SCD inhibition eradicates AML displaying high de novo fatty acid desaturation and synergizes with chemotherapy

Identification of specific and therapeutically actionable vulnerabilities in acute myeloid leukaemia (AML) is needed to improve patients outcome. These features should be ideally present in many patients independently of mutational background. Here we identify de novo fatty acid (FA) desaturation, specifically stearoyl-CoA desaturase (SCD) inhibition, as a therapeutic vulnerability across multiple AML models in vitro and in vivo. We use the novel clinical grade SCD inhibitor SSI-4 to show that SCD inhibition induces AML cell death via pleiotropic effects, and sensitivity is based on their dependency on FA desaturation regardless of mutational profile. SSI-4 efficacy is enhanced by driving FA biosynthesis in vitro while stroma confers protective effects that extend to in vivo models. SCD inhibition increases DNA damage and its combination with standard DNA damage-inducing chemotherapy prolongs survival in aggressive murine AML models. Our work supports developing FA desaturase inhibitors in AML while stressing the importance of identifying predictive biomarkers of response and biologically validated combination therapies to realize their therapeutic potential. One Sentence SummarySCD inhibition is toxic to AML cells with high rates of fatty acid desaturation and in combination with chemotherapy prolongs survival in murine AML models.

cancer biology↗

bioRxiv2022

C/EBPα confers dependence to fatty acid anabolic pathways and vulnerability to lipid oxidative stress in FLT3-mutant leukemia

While transcription factor C/AAT-enhancer binding protein (C/EBP) is critical for normal and leukemic differentiation, its role on cell and metabolic homeostasis is largely unknown in cancer. Here, multi-omics analyses uncovered a coordinated activation of C/EBP and Fms-like tyrosine kinase 3 (FLT3) that increased lipid anabolism in vivo and in patients with FLT3-mutant acute myeloid leukemia (AML). Mechanistically, C/EBP regulated FASN-SCD axis to promote fatty acid (FA) biosynthesis and desaturation. We further demonstrated that FLT3 or C/EBP inactivation decreased mono-unsaturated FAs incorporation to membrane phospholipids through SCD downregulation. Consequently, SCD inhibition enhanced susceptibility to lipid redox stress. Moreover, this C/EBP-dependent adaptation of FA homeostasis was exploited by combining FLT3 and glutathione peroxidase 4 (GPX4) inhibition to trigger lipid oxidative stress, enhancing ferroptotic death of FLT3-mutant AML cells. Altogether, our study reveals a C/EBP function in lipid homeostasis and adaptation to redox stress, and a previously unreported vulnerability of FLT3-mutant AML with promising therapeutic application. SIGNIFICANCEThe transcription factor C/EBP is as a master regulator of normal and leukemic myeloid differentiation. Here, we discovered that C/EBP regulates fatty acid biosynthesis and metabolic adaptation to redox imbalance in leukemic cells. This confers a vulnerability to lipid oxidative stress to FLT3-mutant cells and supports novel therapeutic opportunities for patients.

cancer biology↗

bioRxiv2020

An in vivo CRISPR screening platform for prioritizing therapeutic targets in AML

CRISPR-Cas9-based genetic screens have successfully identified cell type-dependent liabilities in cancers, including acute myeloid leukemia (AML), a devastating hematologic malignancy with poor overall survival. Because most of these screens have been performed in vitro, evaluating the physiological relevance of these targets is critical. We have established a CRISPR screening approach using orthotopic xenograft models to prioritize AML-enriched dependencies in vivo, complemented by the validation in CRISPR-competent AML patient-derived xenograft (PDX) models tractable for genome editing. Our integrated pipeline has revealed several targets with translational value, including SLC5A3 as a metabolic vulnerability for AML addicted to exogenous myo-inositol and MARCH5 as a critical guardian to prevent apoptosis in AML. MARCH5 repression enhanced the efficacy of BCL2 inhibitors such as venetoclax, highlighting the clinical potential of targeting MARCH5 in AML. Our study provides a valuable strategy for discovery and prioritization of new candidate AML therapeutic targets. Statement of significanceThere is an unmet need to improve the clinical outcome of AML. We developed an integrated in vivo screening approach to prioritize and validate AML dependencies with high translational potential. We identified SLC5A3 as a metabolic vulnerability and MARCH5 as a critical apoptosis regulator in AML, representing novel therapeutic opportunities.

cancer biology↗

bioRxiv2020

Adrenomedullin-CALCRL Axis Controls Relapse-Initiating Drug Tolerant Acute Myeloid Leukemia Cells

Drug tolerant leukemic cell subpopulations may explain frequent relapses in acute myeloid leukemia (AML), suggesting that these Relapse-Initiating Cells (RICs) persistent after chemotherapy represent bona fide targets to prevent drug resistance and relapse. We uncovered that the G-protein coupled receptor CALCRL is expressed in leukemic stem cells (LSCs) and RICs, and that the overexpression of CALCRL and/or of its ligand adrenomedullin (ADM) and not CGRP correlates to adverse outcome in AML. CALCRL knockdown impairs leukemic growth, decreases LSC frequency and sensitizes to cytarabine in patient-derived xenograft (PDX) models. Mechanistically, the ADM-CALCRL axis drives cell cycle, DNA repair and mitochondrial OxPHOS function of AML blasts dependent on E2F1 and BCL2. Finally, CALCRL depletion reduces LSC frequency of RICs post-chemotherapy in vivo. In summary, our data highlight a critical role of ADM-CALCRL in post-chemotherapy persistence of these cells, and disclose a promising therapeutic target to prevent relapse in AML.

cancer biology↗

bioRxiv2020

Mitochondrial determinants of response and resistance to venetoclax plus cytarabine duplet therapy in acute myeloid leukemia

The development of resistance to conventional and targeted therapy represents a major clinical barrier in treatment of acute myeloid leukemia (AML). We show that the resistance to cytarabine (AraC) and its associated mitochondrial phenotype were reversed by genetic silencing or pharmacological inhibition of BCL2 in a caspase-dependent manner. BCL2-inhibitor venetoclax (VEN) enhancement of AraC efficacy was independent of differentiation phenotype, a characteristic of response to another combination of VEN with hypomethylating agents (HMA). Furthermore, transcriptional profiles of patients with low response to VEN+AraC mirrored those of low responders to VEN+HMA in clinical trials. OxPHOS was found to be a patient stratification marker predictive of effective response to VEN+AraC but not to VEN+AZA. Importantly, whereas three cell subpopulations specifically emerged in VEN+AraC residual disease and were characterized by distinct developmental and transcriptional programs largely driven by MITF, E2F4 and p53 regulons, they each encoded proteins involved in assembly of NADH dehydrogenase complex. Notably, treatment of VEN+AraC-persisting AML cells with an ETCI inhibitor significantly increased the time-to-relapse in vivo. These findings provide the scientific rationale for new clinical trials of VEN+AraC combinations, especially in patients relapsing or non-responsive to chemotherapy, or after failure of frontline VEN+HMA regimen.

cancer biology↗