Heme promotes venetoclax resistance in multiple myeloma through MEK-ERK signaling and purine biosynthesis.

We previously demonstrated that reduced intrinsic electron transport chain (ETC) activity predicts and promotes sensitivity to the BCL-2 antagonist, venetoclax (Ven) in multiple myeloma (MM). Heme, an iron-containing prosthetic group, and metabolite is fundamental to maintaining ETC activity. Interrogation of the CD2 subgroup of MM from the CoMMpass trial (NCT01454297), which can be used as a proxy for Ven-sensitive MM (VS MM), shows reduced expression of the conserved heme biosynthesis pathway gene signature.

Human plasma-like medium facilitates metabolic tracing and enables upregulation of immune signaling pathways in glioblastoma explants.

Purpose: Metabolism within the tumor microenvironment (TME) represents an increasing area of interest to understand glioma initiation and progression. Stable isotope tracing is a technique critical to the study of tumor metabolism. Cell culture models of this disease are not routinely cultured under physiologically relevant nutrient conditions and do not retain cellular heterogeneity present in the parental TME.

Emerging roles of nucleotide metabolism in cancer.

Nucleotides are substrates for multiple anabolic pathways, most notably DNA and RNA synthesis. Since nucleotide synthesis inhibitors began to be used for cancer therapy in the 1950s, our understanding of how nucleotides function in tumor cells has evolved, prompting a resurgence of interest in targeting nucleotide metabolism for cancer therapy. In this review, we discuss recent advances that challenge the idea that nucleotides are mere building blocks for the genome and transcriptome and highlight ways that these metabolites support oncogenic signaling, stress resistance, and energy homeostasis in tumor cells.

De novo pyrimidine synthesis is a targetable vulnerability in IDH mutant glioma.

Mutations affecting isocitrate dehydrogenase (IDH) enzymes are prevalent in glioma, leukemia, and other cancers. Although mutant IDH inhibitors are effective against leukemia, they seem to be less active in aggressive glioma, underscoring the need for alternative treatment strategies. Through a chemical synthetic lethality screen, we discovered that IDH1-mutant glioma cells are hypersensitive to drugs targeting enzymes in the de novo pyrimidine nucleotide synthesis pathway, including dihydroorotate dehydrogenase (DHODH).

A druggable addiction to de novo pyrimidine biosynthesis in diffuse midline glioma.

Diffuse midline glioma (DMG) is a uniformly fatal pediatric cancer driven by oncohistones that do not readily lend themselves to drug development. To identify druggable targets for DMG, we conducted a genome-wide CRISPR screen that reveals a DMG selective dependency on the de novo pathway for pyrimidine biosynthesis. This metabolic vulnerability reflects an elevated rate of uridine/uracil degradation that depletes DMG cells of substrates for the alternate salvage pyrimidine biosynthesis pathway.

Semi-Automated Computational Assessment of Cancer Organoid Viability Using Rapid Live-Cell Microscopy.

The creation of patient-derived cancer organoids represents a key advance in preclinical modeling and has recently been applied to a variety of human solid tumor types. However, conventional methods used to assess in vivo tumor tissue treatment response are poorly suited for the evaluation of cancer organoids because they are time-intensive and involve tissue destruction. To address this issue, we established a suite of 3-dimensional patient-derived glioma organoids, treated them with chemoradiotherapy, stained organoids with non-toxic cell dyes, and imaged them using a rapid laser scanning confocal microscopy method termed "Apex Imaging.

Antitumor Activity of a Mitochondrial-Targeted HSP90 Inhibitor in Gliomas.

Purpose: To investigate the antitumor activity of a mitochondrial-localized HSP90 inhibitor, Gamitrinib, in multiple glioma models, and to elucidate the antitumor mechanisms of Gamitrinib in gliomas.

Experimental Design: A broad panel of primary and temozolomide (TMZ)-resistant human glioma cell lines were screened by cell viability assays, flow cytometry, and crystal violet assays to investigate the therapeutic efficacy of Gamitrinib. Seahorse assays were used to measure the mitochondrial respiration of glioma cells.

Establishment of patient-derived organoid models of lower-grade glioma.

Background: Historically, creating patient-derived models of lower-grade glioma (LGG) has been challenging, contributing to few experimental platforms that support laboratory-based investigations of this disease. Although organoid modeling approaches have recently been employed to create in vitro models of high-grade glioma (HGG), it is unknown whether this approach can be successfully applied to LGG.

Methods: In this study, we developed an optimized protocol for the establishment of organoids from LGG primary tissue samples by utilizing physiologic (5%) oxygenation conditions and employed it to produce the first known suite of these models.

Amplifying the Noise: Oncometabolites Mask an Epigenetic Signal of DNA Damage.

A recent study (Sulkowski et al., 2020) reveals that oncometabolites, which are produced by metabolic gene mutations in many cancers, sensitize cells to PARP inhibition by antagonizing histone demethylation and obscuring epigenetic marks that are necessary for efficient DNA repair.

Cytosine Deaminase APOBEC3A Sensitizes Leukemia Cells to Inhibition of the DNA Replication Checkpoint.

Mutational signatures in cancer genomes have implicated the APOBEC3 cytosine deaminases in oncogenesis, possibly offering a therapeutic vulnerability. Elevated APOBEC3B expression has been detected in solid tumors, but expression of APOBEC3A (A3A) in cancer has not been described to date. Here, we report that A3A is highly expressed in subsets of pediatric and adult acute myelogenous leukemia (AML).

Antibiotic-Induced Depletion of Anti-inflammatory Clostridia Is Associated with the Development of Graft-versus-Host Disease in Pediatric Stem Cell Transplantation Patients.

Adult stem cell transplantation (SCT) patients with graft-versus-host-disease (GVHD) exhibit significant disruptions in gut microbial communities. These changes are associated with higher overall mortality and appear to be driven by specific antibiotic therapies. It is unclear whether pediatric SCT patients who develop GVHD exhibit similar antibiotic-induced gut microbiota community changes.