Lactate plays a critical role in the tumor microenvironment, driving tumor progression, metastasis, and immune evasion. Despite its importance, in vivo quantification of lactate using magnetic resonance spectroscopy (MRS) has faced challenges, primarily due to the overlapping lipid signal at 1.3 ppm. Current clinical practice employs a long echo time to exploit differences in T2 relaxation between lactate and lipids; however, this approach significantly suppresses signals from other metabolites. Lipid has a notably different T1 relaxation time than lactate and other metabolites, which may be exploited by an inversion recovery sequence to better distinguish them. However, this method has not found wide use because of the loss of signal in other metabolites. Here, we introduce a selective inversion pulse with a short echo time MRS method (SPIR-PRESS), which mitigates this issue. In phantom experiments, SPIR-PRESS successfully suppressed lipid signals that could be misinterpreted as lactate in short TE PRESS spectra, while maintaining sensitivity to the full metabolite profile. SPIR-PRESS demonstrated superior performance in quantifying lactate compared to long echo time PRESS, with ~60% increase in sensitivity for lactate detection compared to conventional PRESS with a 288-ms TE. In a mouse glioma model, SPIR-PRESS clearly detected lactate and other key tumor metabolites (total choline, creatine, NAA) in the tumor, which were not detectable in conventional long TE PRESS. These findings highlight SPIR-PRESS as a promising technique for improved lactate quantification and comprehensive metabolite profiling in tumor environments.

Abstract Patients with hereditary leiomyomatosis and renal cell carcinoma (HLRCC), characterized by mutations in the fumarate hydratase (FH) gene, are at risk for development of aggressive FH-deficient RCCs. FH-deficient tumor cells undergo a pronounced and irreversible metabolic shift to lactate fermentation due in part to loss and mutation of mitochondrial DNA. Fumarate accumulation in FH-deficient tumor cells leads to increased expression of NAD(P)H-quinone oxidoreductase 1 (NQO1) through activation of the NRF2 transcription factor. Although several therapeutic agents have shown promise in the treatment of FH-deficient RCC, clinical outcomes in patients remain unsatisfactory. In this study, we examined the mechanism and therapeutic efficacy of isobutyl-deoxynyboquinone (IB-DNQ), which undergoes futile redox cycling in the presence of NQO1 and oxygen, leading to sustained generation of the highly reactive and toxic superoxide anion. First, we found that patient-derived FH-deficient tumor cells exhibit minimal oxygen consumption in vitro, and EPR oxygen mapping of FH-deficient tumor xenografts in vivo revealed that tumor oxygen levels were elevated relative to other genetically defined in vivo models of RCC. Infusion of IB-DNQ in tumor-bearing animals resulted in rapid and robust non-mitochondrial oxygen consumption in FH-deficient tumor xenografts as measured by both EPR oxygen imaging and photoacoustic mapping of tumor hemoglobin saturation. Repeated doses of IB-DNQ resulted in reduced tumor growth rates. Metabolomic analyses revealed that IB-DNQ treatment strongly suppressed glycolysis and reduced cellular ATP levels by rapidly depleting NADH and NADPH in FH-deficient tumor cells. Finally, [1-13C]pyruvate hyperpolarized MR spectroscopy revealed decreased conversion of pyruvate to lactate in FH-deficient tumor xenografts following IB-DNQ treatment, providing a direct measurement of the impact of IB-DNQ on lactate fermentation in vivo. The combination of these in vivo imaging techniques and metabolite measurements demonstrate that NQO1-activated quinones can effectively target aerobic glycolysis in FH-deficient tumors which rely heavily on lactate fermentation for growth. Citation Format: Yuki Shibata, Shun Kishimoto, Ye Yang, Ming-Hui Wei, Julia Medina-Velazquez, Burchelle Blackman, Jeeva Munasinghe, Viraj Chegu, Vaishnavi S. Srirama, Tyler A. On, Nallathamby Devasahayam, Chandramouli V. Gadisetti, Jeffrey R. Brender, Murali C. Krishna, Daniel R. Crooks, William Marston Linehan. EPR imaging of oxygen consumption driven by NQO1-activated compounds in FH-deficient renal tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7328.

We established a novel syngeneic glioblastoma stem cell (GSC) line from PDGFB-driven RCAS/tv-a glioblastomas and subsequently generated a Pten-deficient derivative, WYZ-1. In vitro, WYZ-1 cells exhibited robust self-renewal, high expression of GSC markers (CD133, Nestin, SOX2), and multipotent differentiation into neuronal and astrocytic lineages. In vivo, intracranial implantation in immunocompetent mice produced highly infiltrative and vascularized tumors with marked proliferation, necrosis, and white matter invasion, closely recapitulating key histopathological features of human glioblastoma. Immunohistochemical analysis confirmed the retention of oncogenic, stem-like, and mesenchymal-associated markers. Importantly, WYZ-1 tumors displayed an immune-excluded (“cold”) tumor microenvironment characterized by dense infiltration of immunosuppressive macrophages/microglial cells within the tumor core and restricted localization of exhausted T cells to the tumor margins. Consistent with these features, WYZ-1 tumors are resistant to temozolomide and anti-PD-1 monotherapy, with only a modest survival benefit observed following CTLA-4 blockade. Collectively, these findings establish WYZ-1 as a highly aggressive, stem-like, and immunocompetent glioblastoma model that mirrors the therapeutic resistance of human disease and provides a valuable platform for investigating tumor biology and evaluating novel immunotherapeutic strategies.

In USA, six million individuals with Sub-Saharan ancestry carry two APOL1 high-risk variants, which increase the risk for kidney diseases. Whether APOL1 high-risk variants increase other diseases under dyslipidemia remains unclear and requires further investigation.We characterized a mouse model to investigate the role of APOL1 in dyslipidemia and cardiovascular diseases. Transgenic mice carrying APOL1 (G0 and G1 variants)on bacterial artificial chromosomes (BAC/APOL1 mice) were crossed with the ApoE knock-out (ApoE-KO) dyslipidemia and atherosclerosis mouse model. The compound transgenic mice were evaluated for the impact of APOL1 on systemic phenotypes. ApoE-KO mice carrying APOL1-G0 and APOL1-G1 did not show differences in the extent of atherosclerotic lesions or aortic calcification, as evaluated by Sudan IV staining and radiographic examination, respectively. However, ~20% of ApoE-KO; BAC/APOL1-G1 mice developed hydrocephalus and required euthanasia. The hydrocephalus was communicating and likely was due to excess cerebrospinal fluid produced by the choroid plexus, where epithelial cells expressed APOL1. Single-nuclear RNA-seq of choroid plexus identified solute transporter upregulation and mTORC2 pathway activation in APOL1-G1-expressing epithelial cells. Further, in the All of Us cohort, we found higher hydrocephalus prevalence among individuals with the APOL1-G1 variant in both recessive and dominant models, supporting the mouse findings. While APOL1-G1 expression in ApoE-KO mice did not worsen cardiovascular disease phenotypes, we uncovered hydrocephalus as a novel APOL1 risk allele-mediated phenotype. These findings extend the spectrum of APOL1-associated pathologies.

Background: Head and neck paragangliomas (HNPGLs) are typically slow-growing, hormonally inactive tumors of parasympathetic paraganglia. Inactivation of prolyl-hydroxylase domain-containing 2 protein causing indirect gain-of-function of hypoxia-inducible factor-2 alpha (HIF-2 alpha), encoded by EPAS1, was recently shown to cause carotid body hyperplasia. We previously described a syndrome with multiple sympathetic paragangliomas caused by direct gain-of-function variants in EPAS1 (Pacak-Zhuang syndrome, PZS) and developed a corresponding mouse model. Methods: We evaluated a cohort of patients with PZS (n 1/4 9) for HNPGL by positron emission tomography, magnetic resonance imaging, and computed tomography and measured carotid body size compared to literature reference values. Resected tumors were evaluated by histologic sectioning and staining. We evaluated the corresponding mouse model at multiple developmental stages (P8 and adult) for lesions of the head and neck by high resolution ex vivo imaging and performed immunohistochemical staining on histologic sections of the identified lesions. Results: hree patients had imaging consistent with HNPGL, one of which warranted resection and was confirmed on histology. Three additional patients had carotid body enlargement (Z-score > 2.0), and 3 had carotid artery malformations. We found that 9 of 10 adult variant mice had carotid body tumors and 6 of 8 had a paraganglioma on the cranio-caval vein, the murine homologue of the superior vena cava; these were also found in 4 of 5 variant mice at post-natal day 8. These tumors and the one resected from a patient were positive for tyrosine hydroxylase, synaptophysin, and chromogranin A. Brown fat in a resected patient tumor carried the EPAS1 pathogenic variant. Conclusions: These findings (1) suggest HNPGL as a feature of PZS and (2) show that these pathogenic variants are sufficient to cause the development of these tumors, which we believe represents a continuous spectrum of disease starting from hyperplasia.

Plots of tumor growth delay vs HF10; pO2; lac/pyr

Supplementary Figure Legends 1-2 from Cediranib/AZD2171 Inhibits Bone and Brain Metastasis in a Preclinical Model of Advanced Prostate Cancer

Supplemental materials and methods

Clonogenic assay for Hs766t cells treated with gemcitabine 100 nM in ambient air and anoxic condition

Benefit of combination therapy over monotherapy.

<p>Lactate to pyruvate ratio and kpyr-lac of individual PDAC tumors in hyperpolarized 13C MRI study.</p>

Supplementary Table 1 from Cediranib/AZD2171 Inhibits Bone and Brain Metastasis in a Preclinical Model of Advanced Prostate Cancer

Supplementary Figure 1 from Cediranib/AZD2171 Inhibits Bone and Brain Metastasis in a Preclinical Model of Advanced Prostate Cancer

<p>Median pO2 and HF10 of individual PDAC tumors in EPR oxygen imaging study.</p>

GM1 gangliosidosis is a rare lysosomal storage disorder affecting multiple organ systems, primarily the central nervous system, and is caused by functional deficiency of β-galactosidase (GLB1). Using CRISPR/Cas9 genome editing, we generated a mouse model to evaluate characteristics of the disease in comparison to GM1 gangliosidosis patients. Our Glb1−/− mice contain small deletions in exons 2 and 6, producing a null allele. Longevity is approximately 50 weeks and studies demonstrated that female Glb1−/− mice die six weeks earlier than male Glb1−/− mice. Gait analyses showed progressive abnormalities including abnormal foot placement, decreased stride length and increased stance width, comparable with what is observed in type II GM1 gangliosidosis patients. Furthermore, Glb1−/− mice show loss of motor skills by 20 weeks assessed by adhesive dot, hanging wire, and inverted grid tests, and deterioration of motor coordination by 32 weeks of age when evaluated by rotarod testing. Brain MRI showed progressive cerebellar atrophy in Glb1−/− mice as seen in some patients. In addition, Glb1−/− mice also show significantly increased levels of a novel pentasaccharide biomarker in urine and plasma which we also observed in GM1 gangliosidosis patients. Glb1−/− mice also exhibit accumulation of glycosphingolipids in the brain with increases in GM1 and GA1 beginning by 8 weeks. Surprisingly, despite being a null variant, this Glb1−/− mouse most closely models the less severe type II disease and will guide the development of new therapies for patients with the disorder.

Immunostaining of hypoxia marker pimonidazole of three pancreatic tumors. Representative pictures of whole tumor area were shown.

Disrupted sleep, including daytime hypersomnolence, is a core symptom reported by primary brain tumor patients and often manifests after radiotherapy. The biological mechanisms driving the onset of sleep disturbances after cranial radiation remains unclear but may result from treatment-induced injury to neural circuits controlling sleep behavior, both circadian and homeostatic. Here, we develop a mouse model of cranial radiation-induced hypersomnolence which recapitulates the human experience. Additionally, we used the model to explore the impact of radiation on the brain. We demonstrated that the DNA damage response following radiation varies across the brain, with homeostatic sleep and cognitive regions expressing higher levels of γH2AX, a marker of DNA damage, than the circadian suprachiasmatic nucleus (SCN). These findings were supported by in vitro studies comparing radiation effects in SCN and cortical astrocytes. Moreover, in our mouse model, MRI identified structural effects in cognitive and homeostatic sleep regions two-months post-treatment. While the findings are preliminary, they suggest that homeostatic sleep and cognitive circuits are vulnerable to radiation and these findings may be relevant to optimizing treatment plans for patients.

Preclinical models that reliably recapitulate the immunosuppressive properties of human gliomas are essential to assess immune-based therapies. GL261 murine glioma cells are widely used as a syngeneic animal model of glioma, however, it has become common practice to transfect these cells with luciferase for fluorescent tumor tracking. The aim of this study was to compare the survival of mice injected with fluorescent or non-fluorescent GL261 cells and characterize the differences in their tumor microenvironment. Mice were intracranially implanted with GL261, GL261 Red-FLuc or GL261-Luc2 cells at varying doses. Cytokine profiles were evaluated by proteome microarray and Kaplan–Meier survival analysis was used to determine survival differences. Median survival for mice implanted with 5 × 104 GL261 cells was 18 to 21 days. The GL261 Red-FLuc implanted mice cells did not reach median survival at any tumor dose. Mice injected with 3 × 105 GL261-Luc2 cells reached median survival at 23 days. However, median survival was significantly prolonged to 37 days in mice implanted with 5 × 104 GL261-Luc2 cells. Additionally, proteomic analyses revealed significantly elevated inflammatory cytokines in the supernatants of the GL261 Red-FLuc cells and GL261-Luc2 cells. Our data suggest that GL261 Red-FLuc and GL261-Luc2 murine models elicit an anti-tumor immune response by increasing pro-inflammatory modulators.