The protective effects of the tuberculosis vaccine Bacillus Calmette-Guerin (BCG) on unrelated infections are thought to be mediated by long-term metabolic changes and chromatin remodeling through histone modifications in innate immune cells such as monocytes, a process termed trained immunity. Here, we show that BCG induction of trained immunity in monocytes is accompanied by a strong increase in glycolysis and, to a lesser extent, glutamine metabolism, both in an in-vitro model and after vaccination of mice and humans. Pharmacological and genetic modulation of rate-limiting glycolysis enzymes inhibits trained immunity, changes that are reflected by the effects on the histone marks (H3K4me3 and H3K9me3) underlying BCG-induced trained immunity. These data demonstrate that a shift of the glucose metabolism toward glycolysis is crucial for the induction of the histone modifications and functional changes underlying BCG-induced trained immunity. The identification of these pathways may be a first step toward vaccines that combine immunological and metabolic stimulation.

Article The neurokinin-1 receptor (NK-1R) and its ligand substance P (SP) are involved in the pathogenesis of certain neural tumors. Because nerves are significantly altered in pancreatic cancer, evidence for alteration of this pathway in human pancreatic cancer was sought. Expression of NK-1R was analyzed by real-time quantitative RT-PCR, in situ hybridization, immunohistochemistry, and Western blot analysis in normal human pancreatic and pancreatic cancer tissue samples and in pancreatic cancer cell lines. Furthermore, the influence of SP analogs and of the NK-1R antagonist MEN 11467 on pancreatic cancer cell growth was analyzed by sulforhodamine B (SRB) assay. By real-time quantitative RT-PCR, NK-1R mRNA was increased 36.7-fold (p < 0.001) in human pancreatic cancer samples compared with normal controls. Enhanced NK-1R expression levels were not related to tumor grade but were associated with advanced tumor stage and poorer prognosis. By in situ hybridization and immunohistochemistry, NK-1R mRNA and immunoreactivity were only occasionally weakly present in acinar and ductal cells in the normal pancreas. In contrast, moderate to strong NK-1R mRNA signals and immunoreactivity were present in most cancer cells. By Western blot analysis, NK-1R was increased 26-fold (p < 0.01) in pancreatic cancer samples in comparison to normal controls. NK-1R mRNA was detected in five pancreatic cancer cell lines by real-time quantitative RT-PCR, with the highest levels in CAPAN-1 cells and the lowest in ASPC-1 cells. SP analogs stimulated pancreatic cancer cell growth, depending on the NK-1R expression level, and this effect could be blocked by a selective NK-1R antagonist. These findings illustrate that the NK-1R pathway is activated in human pancreatic cancer and has the potential to contribute to cancer cell growth, thus suggesting the existence of a neuro-cancer cell interaction in vivo.

The possibility of links between phsychosocial factors and cancer incidence and progression has generated considerable scientific and public interest. Tachykinins, including substance P, neurokinin A and B, hemokinin-1 and endokinins, are a family of neuropeptides, acting through three types of transmembrane G-protein coupled receptors denoted NK1, NK2 and NK3. Besides, their role as neurotransmitters in peripheral and central nervous system, tachykinins and their receptors are also expressed in several non neuronal cells contributing to the fine connections between nervous systems and peripheral organ system such as, respiratory, cardiovascular, immune, endocrine, gastrointestinal and genitourinary. Being so much involved in regulating physiological functions, they, of course, can concur to pathological conditions including cancer. Tachykinins can act on different steps of carcinogenesis. Tumors expressing NK receptors, such as astrocytoma, glioma, neuroblastoma, pancreatic cancer and melanoma, can misuse tachykinin-induced signaling, operating in normal cells, to promote proliferation and survival of cancer cells and to release cytokines and soluble mediators favoring tumor growth. In neuroblastoma, breast and prostate carcinomas tachykinins facilitate tumor metastatic infiltration in the bone marrow. In neuroendocrine carcinoma, tachykinins are responsible of symptoms associated with these pathologies including flushing, diarrhea, wheezing and right heart disease. In addition, regardless tumor histology, tachykinins may favor cancer incidence and metastatic progression by influencing blood flux and neovascularization in tumor formation as well as inducing immunesuppression mediated by neurogenic inflammation due to stress or surgery. However, the precise involvement of tachykinins in cancer pathologies and the potentiality to become effective pharmacological drug targets remain to be fully defined.

The neuropeptide substance P (SP), by stimulating tachykinin NK₁receptors (NK₁R), triggers a number of biological responses in human glioma cells which are potentially relevant for tumour growth. First, radioligand binding studies demonstrated the presence of tachykinin NK₁R on SNB-19, DBTRG-05 MG and U373 MG, but not on U138 MG and MOG-G-GCM human glioma cell lines. Second, application of SP or neurokinin A (NKA) to NK₁R⁺glioma cell lines increased the secretion of interleukin 6 (IL-6) and potentiated IL-6 secretion induced by IL-1β. SP also up-regulated the release of transforming growth factor β1 (TGF-β1) by the U373 MG glioma cell line. Third, SP induced new DNA synthesis and enhanced the proliferation rate of NK₁R⁺, but not of NK₁R^–glioma cell lines. Also, NKA stimulated the proliferation and cytokine secretion in NK₁R⁺glioma cell lines. All the stimulant effects of SP/NKA on NK₁R⁺glioma cell lines were completely blocked by a specific tachykinin NK₁R antagonist, MEN 11467. These data support the potential use of tachykinin NK₁R antagonist for controlling the proliferative rate of human gliomas.