Immunotherapy can lead to long-term survival for some cancer patients, yet generalized success has been hampered by insufficient antigen presentation and exclusion of immunogenic cells from the tumor microenvironment. Here, we developed an approach to reprogram tumor cells in vivo by adenoviral delivery of the transcription factors PU.1, IRF8, and BATF3, which enabled them to present antigens as type 1 conventional dendritic cells. Reprogrammed tumor cells remodeled their tumor microenvironment, recruited, and expanded polyclonal cytotoxic T cells; induced tumor regressions; and established long-term systemic immunity in multiple mouse melanoma models. In human tumor spheroids and xenografts, reprogramming to immunogenic dendritic-like cells progressed independently of immunosuppression, which usually limits immunotherapy. Our study paves the way for human clinical trials of in vivo immune cell reprogramming for cancer immunotherapy.

Genetically engineered ‘lymphoreporter’ mouse strains are used to track melanoma dissemination in vivo, identifying midkine as a tumour-secreted factor that acts at a distance, preparing pre-metastatic niches and serving as an indicator of poor prognosis in patients. Lymph nodes are a common metastatic site of many tumour types, including melanomas. The contribution of lymphangiogenesis to metastatic progression is not well defined, as removing the sentinel lymph node does not always improve the survival chances of melanoma patients. Here the authors develop a 'lymphoreporter' mouse model that allows them to track lymphatic vessels with a VEGFR3 reporter, and use it to visualize metastatic routes during relapse. In addition, the authors identify a mediator of lymphangiogenesis, MIDKINE, that contributes to metastasis and indicates a poor prognosis for patients with melanoma. The authors suggest that VEGFR3 reporters could be useful in the search for further drivers and inhibitors of metastasis. Cutaneous melanoma is a type of cancer with an inherent potential for lymph node colonization, which is generally preceded by neolymphangiogenesis1,2,3. However, sentinel lymph node removal does not necessarily extend the overall survival of patients with melanoma4,5. Moreover, lymphatic vessels collapse and become dysfunctional as melanomas progress6,7. Therefore, it is unclear whether (and how) lymphangiogenesis contributes to visceral metastasis. Soluble and vesicle-associated proteins secreted by tumours and/or their stroma have been proposed to condition pre-metastatic sites in patients with melanoma8,9,10,11,12,13,14. Still, the identities and prognostic value of lymphangiogenic mediators remain unclear2,14. Moreover, our understanding of lymphangiogenesis (in melanomas and other tumour types) is limited by the paucity of mouse models for live imaging of distal pre-metastatic niches15. Injectable lymphatic tracers have been developed7, but their limited diffusion precludes whole-body imaging at visceral sites16. Vascular endothelial growth factor receptor 3 (VEGFR3) is an attractive ‘lymphoreporter’17 because its expression is strongly downregulated in normal adult lymphatic endothelial cells, but is activated in pathological situations such as inflammation and cancer17,18. Here, we exploit this inducibility of VEGFR3 to engineer mouse melanoma models for whole-body imaging of metastasis generated by human cells, clinical biopsies or endogenously deregulated oncogenic pathways. This strategy revealed early induction of distal pre-metastatic niches uncoupled from lymphangiogenesis at primary lesions. Analyses of the melanoma secretome and validation in clinical specimens showed that the heparin-binding factor midkine is a systemic inducer of neo-lymphangiogenesis that defines patient prognosis. This role of midkine was linked to a paracrine activation of the mTOR pathway in lymphatic endothelial cells. These data support the use of VEGFR3 reporter mice as a ‘MetAlert’ discovery platform for drivers and inhibitors of metastasis.

Chimeric antigen receptor (CAR) T-cell therapy is a promising and innovative cancer therapy. However, immunosuppressive tumor microenvironments (TME) limit T cell persistence and durable efficacy. Here, we aimed to identify and target immunosuppressive factors in the TME of neuroblastoma, a pediatric extracranial solid tumor, to improve CAR-T efficacy. Immunosuppressive factors were identified using a multi-omics approach, including single-cell RNA sequencing (scRNA-seq) of 24 neuroblastoma tumors, published bulk-RNA sequencing datasets, and mass-spectrometry of patient-derived tumoroid models. Candidate targets were validated with functional assays in vitro and in vivo. Protein degradation of the top immunosuppressive target by PROTAC technology was used to evaluate the effect on CAR T-cell activity. ScRNA-seq revealed 13 immunosuppressive interactions in the TME of neuroblastoma, two effectors of which, Midkine (MDK) and Macrophage Migration Inhibitory Factor (MIF), were validated as candidate targets across multiple published datasets. Both factors were among the top 6 % of most abundantly secreted factors by patient-derived tumoroid models, substantiating their potential relevance in the TME. In vitro and in vivo functional assays confirmed MIF to be a potent inhibitor of CAR T-cell activation and killing capacity. To translate these findings into a potentially clinically applicable treatment, we explored MIF targeting by PROTAC technology, which significantly enhanced activation of CAR T-cells targeting GPC2 and B7-H3. By defining the immunosuppressive effects of neuroblastoma's TME on CAR T-cell efficacy, revealing the pivotal role of MIF, we provide an analytic pipeline and therapeutic strategy for improving adoptive cell therapies for this pediatric malignancy and potentially other solid tumors.

Immunotherapy leads to long-term survival of cancer patients, yet generalized success has been hampered by insufficient antigen presentation and exclusion of immunogenic cells from the tumor microenvironment. Here, we developed an approach to reprogram tumor cells in vivo by adenoviral delivery of the transcription factors PU.1, IRF8, and BATF3, which enabled them to present antigens as type 1 conventional dendritic cells. Reprogrammed tumor cells remodeled their tumor microenvironment, recruited, and expanded polyclonal cytotoxic T cells, induced complete tumor regressions, and established long-term systemic immunity in different mouse melanoma models. In human tumor spheroids and xenografts, reprogramming to immunogenic dendritic-like cells progressed independently of immunosuppression, which usually limits immunotherapy. Our study paves the way for first-in-human trials and other applications of immune cell reprogramming in vivo . One-Sentence Summary: Reprogramming of tumor cells to cDC1-like cells in vivo elicits systemic and long-term antitumor immunity.

The frequency of specific variants associated with the risk of developing cardiovascular diseases has been extensively studied through genome-wide association studies (GWASs). Differences between populations may be caused by the interaction of several factors, such as environmental and genetic backgrounds. Here, we studied 19 SNPs involved in atherosclerosis (AT) and venous thromboembolism (VTE) risk in the Azorean and mainland Portuguese populations and compared their frequencies with other European, Asian, and African populations. Results revealed that, although there was no difference between Azorean and mainland populations, eight SNPs in ADAMTS7, PCSK9, APOE, and LDLR genes showed significant statistical differences (χ², p < 0.05) when compared with the European population. The multilocus genetic profile (MGP) analysis demonstrated that 7.4% of mainlanders and 11.2% of Azoreans have a high-risk of developing atherosclerosis. The opposite tendency was observed for venous thromboembolism risk, where the mainland population presented a higher risk (6.5%) than the Azorean population (4.1%). Significant differences in VTE-MGP distribution were found among the Azorean geographic groups (p < 0.05), with the Eastern group showing the highest VTE risk. Conversely, for the risk AT-MGP, the Central group shows the highest risk (12.9%). Taken together, the data suggest a risk of developing a cardiovascular disease consistent with the European population. However, the Azorean-specific genetic background and socio-cultural habits (dietary and sedentary) may explain the differences observed, validating the need to assess the allelic and genotypic frequencies between different populations, especially in small geographical locations, such as the Azores archipelago. In conclusion, these findings can improve the prevention, diagnosis, and treatment of high-risk individuals, and contribute to reducing the lifelong burden of cardiovascular diseases in the Azorean population.

While chimeric antigen receptor (CAR) T-cell therapies are showing highly promising first results in neuroblastoma, immunosuppressive tumor microenvironments (TME) limit T cell persistence and durable clinical efficacy. To improve CAR T-cell efficacy further, we applied a multi-omics approach including single-cell RNA sequencing and proteomics, which identified 13 targetable immunosuppressive factors in neuroblastoma. Of these, macrophage migration inhibitory factor (MIF) and midkine (MDK) were validated across multiple published RNA datasets. Moreover, they were secreted in high abundance by neuroblastoma tumoroids. Functional validation experiments revealed MIF as a potent inhibitor of CAR T-cells, in vitro and in vivo. Degradation of MIF by PROTAC technology significantly enhanced CAR T-cell activation targeting GPC2 and B7-H3, providing a potential intervention against MIF. By defining the immunosuppressive effects of neuroblastoma’s TME on CAR T-cell efficacy, particularly the pivotal role of MIF, we provide a therapeutic strategy for improving adoptive cell therapies for this pediatric malignancy.