Distinct malignant cell states and myeloid glutamate signaling associated with aggressive pancreatic neuroendocrine tumors

Arbesfeld-Qiu, J. M.; Cho, J.-W.; Ngyuen, P. T. T.; Lester, N. A.; Su, J.; Guo, J. A.; Hoffman, H.; Shiau, C.; Caldwell, N.; Muratani, S.; Galvan, M.; Proctor, J. E.; Ely, Z.; Wang, S.; Ganci, M.; Dries, R.; Hong, T.; Wo, J.; Boland, G.; Fernandez-del Castillo, C.; Ferrone, C.; Heaphy, C. M.; Zhang, M. L.; Mino-Kenudson, M.; Hemberg, M.; Hwang, W. L.

doi:10.1101/2025.07.15.664730

Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.07.15.664730

Distinct malignant cell states and myeloid glutamate signaling associated with aggressive pancreatic neuroendocrine tumors

View original source ↗Export metadata ↓

Abstract

Pancreatic neuroendocrine tumors (PNET) are rare malignancies of the endocrine pancreas with diverse clinical outcomes. While some PNETs are indolent, others are aggressive and metastasize quickly. However, clinically-relevant molecular stratification for PNET to predict outcomes and guide therapeutic decision-making is limited. Thus, there is an urgent need to understand the molecular heterogeneity of PNETs to refine prognostication and discover novel therapeutic vulnerabilities. We performed single-nucleus RNA sequencing on resected primary and metastatic PNETs (n = 20), including two PNETs with neoadjuvant treatment. We inferred gene expression programs (GEPs) of malignant and non-malignant cells and investigated associations with clinical outcomes. Next, we inferred interactions in the tumor microenvironment (TME) and performed transwell assays for functional validation. Finally, we explored genomic and transcriptomic evolution in a unique case study of an untreated primary PNET with two asynchronous hepatic metastases. A malignant GEP enriched for neural/synaptic signaling genes was associated with worse overall survival, broad chromosomal loss of heterozygosity, and alternative lengthening of telomeres. Another malignant GEP enriched for VEGF signaling increased throughout metastatic progression in our case study. We found that macrophage-derived glutamate drives polarization towards an immunosuppressive phenotype and activates the MAPK/ERK pathway in malignant cells to increase migratory capacity. This study provides a detailed single-nucleus transcriptomic classification of malignant, stromal, and immune cell types and states in PNETs, their interactions in the TME, and associations with clinical outcomes. The refined molecular taxonomy of PNET may guide the development of more efficacious biomarkers and therapeutic strategies.

Source connections

Published article ↗

Explore related subjects

cancer biology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Arbesfeld-Qiu, J. M., Cho, J.-W., Ngyuen, P. T. T., Lester, N. A., Su, J., Guo, J. A., Hoffman, H., Shiau, C., Caldwell, N., Muratani, S., Galvan, M., Proctor, J. E., Ely, Z., Wang, S., Ganci, M., Dries, R., Hong, T., Wo, J., Boland, G., Fernandez-del Castillo, C., Ferrone, C., Heaphy, C. M., Zhang, M. L., Mino-Kenudson, M., Hemberg, M., Hwang, W. L.. 2025-07-19. Distinct malignant cell states and myeloid glutamate signaling associated with aggressive pancreatic neuroendocrine tumors. https://doi.org/10.1101/2025.07.15.664730

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Tet2-Clonal Hematopoiesis Promotes Whereas Dnmt3a-CH Inhibits Breast Cancer Progression During Aging

Clonal hematopoiesis of indeterminate potential (CHIP) driven by somatic mutations in blood cells increases with age and is associated with adverse outcomes in cancer patients. How CHIP mutations influence solid tumor progression remains unclear. Using inducible murine models of Dnmt3a- or Tet2-mutant CHIP combined with orthotopic syngeneic breast cancer models, we demonstrate that upon aging Dnmt3a-mutant CHIP prevents whereas Tet2-mutant CHIP drives breast cancer progression. Dnmt3a-mutant immune infiltrates established interferon-mediated MHCIIhigh tumor-associated macrophages (TAMs) that supported cytotoxic CD8+ T cell-mediated tumor rejection. In contrast, Tet2-mutant TAMs exhibited an inflammatory, immunosuppressive phenotype characterized by increased IL-1 and CXCL2 production, reduced MHCII expression, and impaired T cell recruitment and activation. Therapeutic blockade of IL-1R1 or CXCR2 reduced tumor progression in aged Tet2-mutant CHIP mice and partially restored anti-tumor immunity. These findings establish that the effects of CHIP on cancer are mutation- and age-dependent and identify IL-1/CXCL2-driven inflammation as a therapeutic vulnerability of tumor-promoting Tet2-mutant CHIP.

cancer biology↗

bioRxiv2026

Single Nucleus Profiling Reveals Rewired Tumor-Immune-Stromal Cell Communication in Plasmacytoid Urothelial Carcinoma

Plasmacytoid urothelial carcinoma (PUC) is an aggressive histologic subtype of bladder cancer associated with worse patient outcomes and therapeutic response compared to conventional urothelial carcinoma (CUC). While recent work has demonstrated metastatic lymph nodes from PUC tumors have an inflamed phenotype, how the tumor microenvironment (TME) and crosstalk between tumor, stromal, and immune cells in primary PUC bladder tumors differs from those in CUC remains poorly understood. The impact of these differences on response to immunotherapy is also unknown. To understand TME differences between CUC and PUC and their impact on cell signaling, we performed single nucleus RNA sequencing on PUC and CUC tumors, as well as Xenium spatial transcriptomics on a mixed CUC / PUC tumor. We identified increased signaling between PUC-enriched, CDH1-low urothelial cells, immunosuppressive lipid-associated macrophages, and SFRP2+/CTHRC1+ fibroblasts in PUC tumors compared to CUC. Spatial transcriptomics identified increased macrophage infiltration in PUC histology and colocalization of PUC tumor cells, immunosuppressive macrophages, and SFRP2+ fibroblasts. Taken together, this study delineates PUC architecture and demonstrates interplay CDH1-low tumor cells, EMT, and immunosuppressive macrophages, identifying possible therapeutic vulnerabilities in PUC.

cancer biology↗

bioRxiv2026

The Phospholipase A2 Activity of Peroxiredoxin 6 Protects Hepatocarcinoma Cells Against Ferroptosis and Mitophagy Impairment

Peroxiredoxin 6 (PRDX6) is a moonlighting protein that plays a key role in regulating redox homeostasis and lipid metabolism through its unique dual peroxidase and calcium-independent phospholipase A2 (iPLA2) activities. Here, we generated a stable HepG2 cell line harboring a D140A mutation to selectively ablate iPLA2 activity, and we compared its phenotype with that of wild-type (WT) and PRDX6-knockout (KO) cells. D140A exhibited low ROS leves, similar to WT cells, confirming that oxidative stress is due to peroxidase deficiency. In contrast, D140A cells displayed higher lipid peroxidation than WT cells, though significantly lower than that of KO cells. Furthermore, the D140A mutant mirrored the KO phenotype regarding intracellular ferrous iron accumulation, impaired lipid droplet biogenesis, and the downregulation of the key ferroptosis regulator GPX4. Mechanistically, integrated proteomic, lipidomic, and enzymatic analyses revealed that a deficiency in iPLA2 activity of PRDX6 disrupted the release of key lipid species necessary for cell structure and signaling. Consequently, organelles involved in lipid synthesis and trafficking, such as peroxisomes, endoplasmic reticulum, mitochondria and lipid droplet, were affected. Specifically, we found that mitochondria exhibited a reduction in cristae and a diminished capacity for mitophagy and autophagy, which ultimately makes cells much more susceptible to erastin-induced ferroptotic cell death. Taken together, our findings demonstrate that PRDX6 iPLA2 activity uniquely coordinates organelle lipid homeostasis and mitophagy to protect cancer cells from ferroptotic cell death. Consequently, the use of iPLA2 inhibitors such as MJ33, which decreased PRDX6 iPLA2 activity to a level comparable to the mutant D140A, could represent a promising therapeutic strategy for inducing ferroptotic cell death in hepatocellular carcinoma.

cancer biology↗