A hallmark of cancer, including pancreatic ductal adenocarcinoma (PDA), is a massive stromal and inflammatory reaction. Many efforts have been made to identify the anti- or protumoral role of cytokines and immune subpopulations within the stroma. Here, we investigated the role of interleukin-17A (IL17A) and its effect on tumor fibroblasts and the tumor microenvironment. We used a spontaneous PDA mouse model (KPC) crossed to IL17A knockout mice to show an extensive desmoplastic reaction, without impaired immune infiltration. Macrophages, especially CD80⁺ and T cells, were more abundant at the earlier time point. In T cells, a decrease in FoxP3⁺ cells and an increase in CD8⁺ T cells were observed in KPC/IL17A^−/− mice. Fibroblasts isolated from IL17A^+/+ and IL17A^−/− KPC mice revealed very different messenger RNA (mRNA) and protein profiles. IL17A^−/− fibroblasts displayed the ability to restrain tumor cell invasion by producing factors involved in extracellular matrix remodeling, increasing T cell recruitment, and producing higher levels of cytokines and chemokines favoring T helper 1 cell recruitment and activation and lower levels of those recruiting myeloid/granulocytic immune cells. Single-cell quantitative PCR on isolated fibroblasts confirmed a very divergent profile of IL17A-proficient and -deficient cells. All these features can be ascribed to increased levels of IL17F observed in the sera of IL17A^−/− mice, and to the higher expression of its cognate receptor (IL17RC) specifically in IL17A^−/− cancer-associated fibroblasts (CAFs). In addition to the known effects on neoplastic cell transformation, the IL17 cytokine family uniquely affects fibroblasts, representing a suitable candidate target for combinatorial immune-based therapies in PDA. Significance There are controversial data about the protumoral role of pancreatic cancer stroma, and dissecting multiple aspects will help to develop effective tailored therapies. Interleukin-17A (IL17A) has been reported to accelerate pancreatic acinar–ductal metaplasia, be important for maintaining stem-like cancer cells, and recruit immunosuppressive granulocytes into the tumor. Here we unveil a relationship between IL17A and pancreatic stromal cells, which strongly modifies their gene and protein expression profiles. Ablation of IL17A, in fact, modifies the cytokines/factors released by tumor fibroblasts by limiting T cell immunosuppression. IL17A inhibition may represent an important tool for designing novel combined therapeutic approaches.

Pancreatic Ductal Adenocarcinoma (PDA) is an almost incurable radio- and chemo-resistant tumor, and its microenvironment is characterized by a strong desmoplastic reaction associated with a significant infiltration of T regulatory lymphocytes and myeloid-derived suppressor cells (Tregs, MDSC). Investigating immunological targets has identified a number of metabolic and cytoskeletal related molecules, which are typically recognized by circulating antibodies. Among these molecules we have investigated alpha-enolase (ENO1), a glycolytic enzyme that also acts a plasminogen receptor. ENO1 is also recognized by T cells in PDA patients, so we developed a DNA vaccine that targets ENO1. This efficiently induces many immunological processes (antibody formation and complement-dependent cytotoxicity (CDC)-mediated tumor killing, infiltration of effector T cells, reduction of infiltration of myeloid and Treg suppressor cells), which significantly increase the survival of genetically engineered mice that spontaneously develop pancreatic cancer. Although promising, the ENO1 DNA vaccine does not completely eradicate the tumor, which, after an initial growth inhibition, returns to proliferate again, especially when Tregs and MDSC ensue in the tumor mass. This led us to develop possible strategies for combinatorial treatments aimed to broaden and sustain the antitumor immune response elicited by DNA vaccination. Based on the data we have obtained in recent years, this review will discuss the biological bases of possible combinatorial treatments (chemotherapy, PI3K inhibitors, tumor-associated macrophages, ENO1 inhibitors) that could be effective in amplifying the response induced by the immune vaccination in PDA.

Background: Interleukin (IL)17A is a member of the IL17 cytokine family, which is released by both immune and non-immune cells such as tumor and stromal cells into the tumor microenvironment. IL17 receptors are also widely expressed in different type of cells. Among all the members, IL17A is the most controversial in regulating tumor immunity. Here, we investigated how IL17A inhibition modulated macrophage differentiation and metabolism in the presence or absence of gemcitabine. Gemcitabine is the gold standard drug for treating pancreatic cancer and can increase macrophage antitumoral activities. Results: We observed some unique features of macrophages polarized in the absence of IL17A, in terms of RNA and protein expression of typical phenotypic markers, and we demonstrated that this paralleled specific changes in their metabolism and functions, such as the induction of an antitumor response. Interestingly, these features were almost maintained or enhanced when macrophages were treated with gemcitabine. We also demonstrated that the anti-IL17A antibody effectively reproduced features of macrophages derived from IL17A knock-out mice. Conclusion: Overall, we provide a proof-of-concept that combining an anti-IL17A antibody with gemcitabine may represent an effective strategy to modulate macrophages and enhance the anti-tumor response, especially in pancreatic cancer where gemcitabine is widely used.

Neuroblastoma, like many aggressive cancers, exhibits phenotypic heterogeneity, contributing to therapy resistance and disease progression. However, direct evidence of how phenotypic plasticity influences tumour evolution remains limited. Using a multi-resolution quantitative approach, we define the principles, types, and dynamics of plasticity in neuroblastoma at unprecedented resolution. We demonstrate that intrinsic plasticity is a model-dependent process that enables the coexistence of drug-sensitive and drug-resistant states in environmentally stable conditions, positioning plasticity as a bet-hedging strategy that allows tumours to anticipate environmental changes. Additionally, we show plasticity varies across lineages and single-cell-derived clones, establishing that it is not merely an induced response but a heritable and selectable trait. By simultaneously mapping plasticity at and clonal dynamics in evolving neuroblastoma populations, we show plasticity is shaped by selective pressures, reinforcing its role as a fundamental driver of neuroblastoma evolution in a treatment- and genetic background-dependent manner. We define three distinct modes of plasticityled adaptation. In the selection of the plasticity model, strong selective pressure temporarily constrains phenotypic transitions, but they reemerge with greater dynamics once the stressor is removed, favouring the selection of highly plastic clones. In the adaptive plasticity model, phenotypic transitions actively reshape tumour heterogeneity, allowing for rapid adaptation to treatment while minimising the impact of clonal selection. Finally, in the plasticity equilibrium model, phenotypic transitions persist at baseline, maintaining a state of phenotypic fluidity, with clonal selection ultimately dictating tumour evolution. These findings highlight the diverse, context-dependent strategies that neuroblastoma populations employ to navigate selective pressures and therapy resistance, emphasizing the need for plasticity-targeting therapeutic approaches to disrupt tumour adaptation and improve treatment outcomes. Teaser: Natural selection and phenotypic transitions shape adaptive evolution, guiding neuroblastoma survival under treatment pressure.

Nine mucoraiean fungai genera including 18 species were examined for their ability to utilise a series of nitrogen containing compounds and to grow at an aw of 0.955 on solid media The nitrogen concentration in the media was 0.1 g/1 and the series of nitrogen containing compounds were ammonium chloride, asparagine, sodium glutamate, sodium nitrite and potassium nitrate. The genera were Actinomucor Schostak. Backusella Hesselt, & J.J. Ellis, Cunningharnella Matr., Gongronella Ribaldi, Mortierella Coem. Mucor Fresen, Rhizomucor Lucet & Costantin, Rhizopus Ehrenb and Thamnostylum Arx & H, P. Upadhyay, Thirty-nine fungal strains obtained from culture collections (CBS, MUFS and PPRI), as well as 12 soil isolates from the Karoo, were tested. All the species and strains tested in this study were able to utilise asparagine and glutamate. Strains belonging to Cunningharnella, Mucor racemosus Fresen., Rhizopus microsporus Tiegh. and Rhizopus stolonifer (Ehrenb.: Fr) Vuill were unable to utilise ammonium chloride. Strains of Cunningharnella, Mortierella, Rhizomucor, Rhizopus microsporus and Rhizopus stoionifer were unable to grow on nitrate as sole nitrogen source. Nitrite was found to be toxic to species belonging to Cunningharnella, Mortierella, Rhizomucor, Rhizopus and Thamnostylum. Members of Gongronella, Mortierella, Mucor racemosus, Rhizomucor and Thamnostylum were unable to grow at an aw of 0.955