Research articles

Huot et al. investigate the differences in natural killer (NK) cells in lymph nodes during pathogenic and nonpathogenic simian immunodeficiency virus (SIV) infection of cynomolgus macaques and African green monkeys (AGMs), respectively. Their findings suggest that NK cells are specifically recruited to follicles in AGMs and regulate SIV replication in the lymph node.

Concomitant overexpression of microRNAs miR-100 and miR-125b-1 within the host long non-coding RNA MIR100HG induces cetuximab resistance in cancer in the absence of previously associated genetic alterations. miR-100 and miR-125b target negative regulators of Wnt/β-catenin signaling and sustain drug resistance through feedback inhibition of GATA6 expression and this resistance can be overcome by pharmacological inhibition of Wnt activity. These findings, together with those by Tan et al. in the previous issue, highlight the emerging functional role of non-coding RNAs in modulating the response to anti-cancer therapies.

Microenvironmental pressures in glioblastoma select for glioma stem cells (GSCs) subpopulations that are maintained through preferential activation of BMI1 and EZH2 in different niches. Given the high degree of intratumor heterogeneity, combined pharmacological inhibition of Polycomb repressive complexes targets proneural and mesenchynmal GSCs and expands lifespan in mice, warranting the therapeutic evaluation of this approach in patients with glioblastoma.

Hiroyuki Arai and colleagues characterize a new group of epoxy ω-3 fatty acid–derived proinflammatory lipid mediators, an enzyme mediating their biosynthesis and a signaling pathway by which they regulate a threshold of mast cell activation and anaphylaxis, revealing new targets for mast cell–mediated diseases.

Obesity induces hypoxia and upregulation of HIF-2α in the gastrointestinal tract, resulting in excess ceramide production and exacerbation of NAFLD.

Combined inhibition of oncogene-driven glucose uptake and induction of cytoplasmic-p53 activity induces apoptosis in a subset of glioblastoma samples. In mice, PET imaging of glucose uptake predicts glioblastoma response to this combination therapy.

Sympathetic neuron–associated macrophages act as a local sink for norepinephrine, leading to reduced thermogenesis and increased obesity.

Frequent loss-of-function mutations in KEAP1, a master regulator of the NRF2 antioxidant pathway, accelerate mutant KRAS driven lung carcinogenesis, but also impose a dependency of these tumors on glutaminolysis. Using a precision medicine–based approach, this work uncovers a metabolic vulnerability of KRAS–KEAP1-mutant lung cancers that can be therapeutically exploited using currently available glutaminase inhibitors and provides a scientific rationale for patient selection in clinical trials.

Quantifying the total-body virus burden in HIV-infected individuals is necessary to understand viral persistence and guide development of cure strategies. Here, Estes et al. find a high burden of residual virus in tissues of SIV-infected monkeys and HIV-infected humans, and evidence of low-level viral replication, even under antiretroviral therapy.

Amplification of chromosome 1q21.3 distinguishes cells with tumor-initiating capacity that drive tumor recurrence across different breast cancer subtypes. A droplet digital PCR assay in circulating free tumor DNA identifies patients with early-stage cancer at high risk of relapse and predicts response to therapy in the metastatic setting. Pharmacological blockade of targets within this amplicon using a clinically available compound prevents tumor recurrence, suggesting a potential therapeutic approach to improve the clinical management of patients harboring 1q21.3-amplified breast tumors.

Factors secreted by metastatic a primary tumors induce an early phenotypic switch in perivascular cells at distant pre-metastatic niches. By using sophisticated lineage-tracing mouse models, the authors demonstrate that enhanced KLF4 expression in these cells increases their ability to proliferate and migrate away from the vasculature, and augments fibronectin deposition, which contributes to metastatic growth. These findings increase the mechanistic understanding of the metastatic process and uncover a role for perivascular plasticity that could be targeted to prevent metastasis.

Treatment with tyrosine kinase inhibitors results in a survival benefit in patients with chronic myeloid leukemia (CML). However, relapse due to persistent leukemic stem cells (LSCs) requires additional selective targets for efficient eradication of the disease. Metabolomic analyses on patient-derived CML LSCs reveal that these have an increased dependency on oxidative metabolism that renders them sensitive to treatment with tigecycline, an FDA-approved inhibitor of mitochondrial translation. These findings uncover a new metabolic vulnerability in CML and provide a rational approach for further clinical evaluation.

Transcriptomic profiling using a newly-developed cre-inducible method to biotinylate wild-type and mutant MeCP2 protein highlights the cellular heterogeneity of transcriptional changes in rodent models of Rett Syndrome, including cell-type- and subcellular compartment-specific differences in male brains and X-linked mosaicism in female brains.

The N⁶-methyladenosine (m⁶A) modification in mRNAs, generated by the enzyme METTL3, controls normal human hematopoietic stem/progenitor cell differentiation and maintains the undifferentiated leukemic phenotype of human acute myeloid leukemia cells.

A silent single-nucleotide variant (SNV) affecting the transcription of a long noncoding RNA (lncRNA EGFR-AS1) within the EGFR coding region alters the EGFR isoform ratio and modulates oncogene addiction and response to EGFR tyrosine kinase inhibitors in squamous-cell cancers. Proof-of-concept validation in patients supports the notion that this SNV and levels of the lncRNA could be used to predict response to therapy in a clinical setting. These results, together with findings by Bal et al., uncover the functional role of noncoding RNAs in modulating the response to targeted therapies in cancer.

John Harty and colleagues report that, in mouse models of malaria, regulatory T cells expand, as in humans, and inhibit conventional T cells and germinal center B cells, thereby impairing protective responses against blood-stage disease. Timed blockade of the inhibitory receptor CTLA-4 cured infection in mice and promoted cross-protective blood-stage immunity against a different Plasmodium species.

Simultaneous activation of Wnt and Shh pathways in murine neural precursor cells results in the formation of embryonal tumors with multilayered rosettes (ETMR) that recapitulate the histological and molecular features of human tumors. This novel mouse model represents a platform for evaluating therapeutic approaches for this rare malignant pediatric brain tumor, and provides novel insights into the cell of origin and molecular mechanisms driving the disease.

Inactivating mutations in ACTRT1 or surrounding noncoding sequences transcribed into functional enhancer RNAs cause aberrant activation of Hedgehog signaling in both sporadic and inherited forms, such as Bazex–Dupré–Christol syndrome, of basal cell carcinoma. These findings identify a new tumor-suppressor gene and underscore the functional relevance of genomic alterations in noncoding transcribed regions in tumor development.

Thomas Geisbert and colleagues show that a cocktail of monoclonal antibodies protects cynomolgus monkeys from lethal Lassa fever virus infection, including when administration is delayed by more than a week after viral challenge.

GDF15 has potent anti-obesity effects, but its receptor was previously unknown. GFRAL has now been identified as the receptor for GDF15, and it mediates the effects of GDF15 via central actions in the hindbrain.