No abstract

Pancreatic cancer is a leading cause of cancer mortality and is projected to become the second-most common cause of cancer mortality in the next decade. While gene-wide association studies and next generation sequencing analyses have identified molecular patterns and transcriptome profiles with prognostic relevance, therapeutic opportunities remain limited. Among the genes that are upregulated in pancreatic ductal adenocarcinomas (PDAC), the leukaemia inhibitory factor (LIF), a cytokine belonging to IL-6 family, has emerged as potential therapeutic candidate. LIF is aberrantly secreted by tumour cells and promotes tumour progression in pancreatic and other solid tumours through aberrant activation of the LIF receptor (LIFR) and downstream signalling that involves the JAK1/STAT3 pathway. Since there are no LIFR antagonists available for clinical use, we developed an in silico strategy to identify potential LIFR antagonists and drug repositioning with regard to LIFR antagonists. The results of these studies allowed the identification of mifepristone, a progesterone/glucocorticoid antagonist, clinically used in medical abortion, as a potent LIFR antagonist. Computational studies revealed that mifepristone binding partially overlapped the LIFR binding site. LIF and LIFR are expressed by human PDAC tissues and PDAC cell lines, including MIA-PaCa-2 and PANC-1 cells. Exposure of these cell lines to mifepristone reverses cell proliferation, migration and epithelial mesenchymal transition induced by LIF in a concentration-dependent manner. Mifepristone inhibits LIFR signalling and reverses STAT3 phosphorylation induced by LIF. Together, these data support the repositioning of mifepristone as a potential therapeutic agent in the treatment of PDAC.

Farnesoid‐x‐receptor (FXR) agonists, currently trialed in patients with non‐alcoholic steatosis (NAFLD), worsen the pro‐atherogenic lipid profile and might require a comedication with statin. Here we report that mice feed a high fat/high cholesterol diet (HFD) are protected from developing a pro‐atherogenic lipid profile because their ability to dispose cholesterol through bile acids. This protective mechanism is mediated by suppression of FXR signaling in the liver by muricholic acids (MCAs) generated in mice from chenodeoxycholic acid (CDCA). In contrast to CDCA, MCAs are FXR antagonists and promote a CYP7A1‐dependent increase of bile acids synthesis. In mice feed a HFD, the treatment with obeticholic acid, a clinical stage FXR agonist, failed to improve the liver histopathology while reduced Cyp7a1 and Cyp8b1 genes expression and bile acids synthesis and excretion. In contrast, treating mice with atorvastatin mitigated liver and vascular injury caused by the HFD while increased the bile acids synthesis and excretion. Atorvastatin increased the percentage of 7α‐dehydroxylase expressing bacteria in the intestine promoting the formation of deoxycholic acid and litocholic acid, two GPBAR1 agonists, along with the expression of GPBAR1‐regulated genes in the white adipose tissue and colon. In conclusion, present results highlight the central role of bile acids in regulating lipid and cholesterol metabolism in response to atorvastatin and provide explanations for limited efficacy of FXR agonists in the treatment of NAFLD.

BackgroundCD73 is an ectonucleotidase producing the immunosuppressor mediator adenosine. Elevated levels of circulating CD73 in patients with cancer have been associated with disease progression and poor response to immunotherapy. Immunosuppressive pathways associated with exosomes can affect T-cell function and the therapeutic efficacy of anti-programmed cell-death protein 1 (anti-PD-1) therapy. Here, we conducted a retrospective pilot study to evaluate levels of exosomal CD73 before and early during treatment with anti-PD-1 agents in patients with melanoma and its potential contribution to affect T-cell functions and to influence the clinical outcomes of anti-PD-1 monotherapy.MethodsExosomes were isolated by mini size exclusion chromatography from serum of patients with melanoma (n=41) receiving nivolumab or pembrolizumab monotherapy. Expression of CD73 and programmed death-ligand 1 (PD-L1) were evaluated on exosomes enriched for CD63 by on-bead flow cytometry. The CD73 AMPase activity was evaluated by mass spectrometry, also in the presence of selective inhibitors of CD73. Interferon (IFN)-γ production and granzyme B expression were measured in CD3/28 activated T cells incubated with exosomes in presence of the CD73 substrate AMP. Levels of CD73 and PD-L1 on exosomes were correlated with therapy response. Exosomes isolated from healthy subjects were used as control.ResultsIsolated exosomes carried CD73 on their surface, which is enzymatically active in producing adenosine. Incubation of exosomes with CD3/28 activated T cells in the presence of AMP resulted in a significant reduction of IFN-γ release, which was reversed by the CD73 inhibitor APCP or by the selective A2A adenosine receptor antagonist ZM241385. Expression levels of exosomal CD73 from serum of patients with melanoma were not significantly different from those in healthy subjects. Early on-treatment, expression levels of both CD73 and PD-L1 on exosomes isolated from patients receiving pembrolizumab or nivolumab monotherapy were significantly increased compared with baseline. Early during therapy exosomal PD-L1 increased in responders, while exosomal CD73 resulted significantly increased in non-responders.ConclusionsCD73 expressed on exosomes from serum of patients with melanoma produces adenosine and contributes to suppress T-cell functions. Early on-treatment, elevated expression levels of exosomal CD73 might affect the response to anti-PD-1 agents in patients with melanoma who failed to respond to therapy.

Fabry disease is caused by a deficiency of lysosomal alpha galactosidase and has a very large genotypic and phenotypic spectrum. Some patients who carry hypomorphic mutations can benefit from oral therapy with a pharmacological chaperone. The drug requires a very precise regimen because it is a reversible inhibitor of alpha-galactosidase. We looked for molecules that can potentiate this pharmacological chaperone, among drugs that have already been approved for other diseases. We tested candidate molecules in fibroblasts derived from a patient carrying a large deletion in the gene GLA, which were stably transfected with a plasmid expressing hypomorphic mutants. In our cell model, three drugs were able to potentiate the action of the pharmacological chaperone. We focused our attention on one of them, acetylsalicylic acid. We expect that acetylsalicylic acid can be used in synergy with the Fabry disease pharmacological chaperone and prolong its stabilizing effect on alpha-galactosidase.