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The NPM1 gene is frequently a target of genetic alteration in hematological tumors, particularly of the myeloid lineage. Complete inactivation of Npm1 in the mouse disrupts primitive hematopoiesis and results in embryonic lethality. Npm1 heterozygosity produces features similar to those of MDS that progress to overt leukemia, and specific point mutations of Npm1 lead to bone marrow failure due to loss of hematopoietic stem cells. However, little is known about NPM1’s role in mature, differentiated cells. Here we generated a conditional mouse mutant to inactivate Npm1 across the myelomonocytic lineage, and investigated its ability to influence macrophage maturation and function. We found that Npm1 is not required to maintain macrophage viability, while its loss in mature macrophages reduces production of reactive oxygen species, chemotactic properties and phagocytic capacity. Taking advantage of our recently established Npm1D180del mouse model of ribosome dysfunction and hematological disease, we identify cellular translation and rRNA 2’-O-methlyation as a crucial element in controlling macrophage function. These analyses demonstrate a role for Npm1 in adult immune cells, and reveal the importance of translation regulation in macrophage function.Statement of significanceMacrophages are a major component of the immune response to various insults including to cancer. Here we show that NPM1, the most frequently mutated gene in acute myeloid leukemia, displays a critical role in macrophage function, and we identify ribosome deregulation as one of the underlying mechanisms.

A major barrier to the successful application of nanotechnology for cancer treatment is the efficient delivery of therapeutic payloads to metastatic tumor deposits. We have previously discovered that cabozantinib, a tyrosine kinase inhibitor, triggers neutrophil-mediated anti-cancer innate immunity, resulting in tumor regression in an aggressive PTEN/p53-deficient genetically engineered murine model of advanced prostate cancer. Here, we specifically investigated the potential of cabozantinib-induced neutrophil activation and recruitment to enhance delivery of bovine serum albumin (BSA)-coated polymeric nanoparticles (NPs) into murine PTEN/p53-deficient prostate tumors. Based on the observation that BSA-coating of NPs enhanced association and internalization by activated neutrophils in vitro, relative to uncoated NPs, we systemically injected BSA-coated, dye-loaded NPs into prostate-specific PTEN/p53-deficient mice that were pre-treated with cabozantinib. Flow cytometric analysis revealed a 4-fold increase of neutrophil-associated NPs within the tumor microenvironment (TME) of mice pre-treated with cabozantinib relative to untreated controls. At steady-state, following 3 days of cabozantinib/NP administration, 1% of systemically injected dye-loaded NPs selectively accumulated within the TME of mice that were pre-treated with cabozantinib, compared to 0.11% uptake for mice that did not receive cabozantinib pre-treatment. Strikingly, neutrophil depletion with Ly6G antibody abolished NP accumulation in tumors to baseline levels, demonstrating targeted neutrophil-mediated NP delivery to the prostate TME. In summary, we have discovered a novel nano-immunotherapeutic strategy for enhanced intratumoral delivery of injected NPs, which results in significantly higher NP accumulation than reported strategies in the nanotechnology literature to-date.

Circular RNAs (circRNAs) are widely expressed, but their functions remain largely unknown. To study circRNAs in a high-throughput manner, short hairpin RNA (shRNA) screens1 have recently been used to deplete circRNAs by targeting their unique back-splicing junction (BSJ) sites. Here, we report frequent discrepancies between shRNA-mediated circRNA knockdown efficiency and the corresponding biological effect, raising pressing concerns about the robustness of shRNA screening for functional circRNAs. To address this issue, we leveraged the CRISPR/Cas13d system2 for circRNAs functional screenings. We optimized a strategy for designing single guide RNAs to deplete circRNAs. We then performed shRNA and CRISPR/Cas13d parallel screenings and demonstrated that shRNA-mediated circRNAs screening yielded a high rate of false positives phenotypes, while optimized CRISPR/Cas13d led to the identification of bona-fide functional circRNAs. Collectively, we developed a specific and reliable approach to functionalize circRNAs in a high-throughput manner.

Patient-derived models are transforming translational cancer research. It is not clear if the emergence of patient-derived organoid (PDO) models can extend the utility of the widely used patient-derived xenograft (PDX). In addition, the utility of PDO models for serum biomarker discovery is not known. Here, we demonstrate that PDO models recapitulate the genomics, cell biology, glycomics and drug responses observed in PDX models. Furthermore, we demonstrate the applicability of PDO models for identification of N-glycans that are enriched in the glycome of pancreatic ductal adenocarcinoma (PDAC). Surprisingly, among all the glycans observed in PDX and PDOs, a core set of 57 N-glycans represent 50-94% of the relative abundance of all N-glycans detected, suggesting that only a subset of glycans dominate the cell surface landscape in PDAC. In addition, we outline a tumor organoid-based pipeline to identify surface proteins in extracellular vesicles (EV) from media supernatant of PDO cultures. When combined with the affinity-based validation platform, the EV surface proteins discovered in PDOs are effective in differentiating patients with PDAC from those with benign pancreatitis in the clinic, identifying PDO as powerful discovery platform for serum biomarkers. Thus, PDOs extend the utility of the archival collections of PDX models for translational research and function as a powerful platform for identification of clinically-actionable biomarkers in patients blood.Significance statementTumor organoids extend the utility of PDX models as platforms for investigating drug response, glycosylation changes and function as new platforms for discovering blood-based biomarkers

The extraordinary endeavor to faithfully model human disorders in mice began in the early 1900s, and in the century since has delivered fundamental advances in our understanding and treatment of human disease. Although it could not be appreciated at the time, 99% of mouse protein-coding genes have an equivalent homolog in the human genome, despite the striking differences in appearance between mouse and man. This remarkable genetic similarity, together with our ability to finely engineer the murine genome, has made the mouse the ideal animal in which to model and analyze human biology and disease. Here we describe this remarkable shared journey between human and mouse, and envisage the next generation of mouse models, which will no doubt prove increasingly sophisticated and even more faithful to human disease. We also address the strategic use of mice in the fight against cancer, and the role they will play in the development of therapies to eradicate this disease.