Interferon gamma (IFN-c) and leukemia inhibitory factor (LIF) are key gestational factors that may differentially affect leukocyte function during gestation. Because IFN-c induces a pro-inflammatory phenotype in macrophages and because trophoblast cells are principal targets of LIF in the placenta, we investigated whether and how soluble factors from trophoblast cells regulate the effects of IFN-c on macrophage activation. IFN-c reduces macrophage motility, but enhances Stat1 activation, pro-inflammatory gene expression and cytotoxic functions. Soluble factors from villous cytotrophoblasts (vCT1LIF cells) and BeWo cells (BW/ST1LIF cells) that were differentiated in the presence of LIF inhibit macrophage Stat1 activation but inversely sustain Stat3 activation in response to IFN-c. vCT1LIF cells produce soluble factors that induce Stat3 activation; this effect is partially abrogated in the presence of neutralizing anti-interleukin 10 (IL-10) antibodies. Moreover, soluble factors from BW/ST1LIF cells reduce cell proliferation but enhance the migratory responses of monocytes. In addition, these factors reverse the inhibitory effect of IFN-c on monocyte/macrophage motility. BW/ST1LIF cells also generate IFN-c-activated macrophages with enhanced IL-10 expression, but reduced tumor-necrosis factor alpha (TNF-a), CD14 and CD40 expression as well as impaired cytotoxic function. Additional assays performed in the presence of neutralizing anti-IL-10 antibodies and exogenous IL-10 demonstrate that reduced macrophage cytotoxicity and proliferation, but increased cell motility result from the ability of trophoblast IL-10 to sustain Stat3 activation and suppress IFN-c-induced Stat1 activation. These in vitro studies are the first to describe the regulatory role of the LIF-trophoblast-IL-10 axis in the process of macrophage activation in response to pro-inflammatory cytokines.

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U sually caused by progressive atherosclerosis and associated thrombosis, peripheral arterial disease (PAD) is characterized by a reduced blood flow to the lower limbs, leading to ischemia during physical exertion and intermittent claudication as clinical presentation. 1 Intermittent claudication, classically defined by pain and muscle cramps when walking, results in a greatly reduced walking capacity and functional status. 2,3 This functional decline lowers patient quality of life and willingness to engage in physical activity, which further worsens the risk of cardiovascular disease 4 and premature mortality. 5 For these reasons, improving walking capacity is now considered a priority for the treatment of PAD. 6 Aerobic exercise, typically in the form of walking, is considered a first-line treatment in this population. 7 Scientific evidence supports the existing guidelines that recommend ≥3/wk of supervised exercise sessions of intermittent walking, according to the pain threshold (3-4/5), for 30-45 min/ session, for ≥3 mo. [7][8][9] Recent meta-analyses and clinical trials have shown an increase in maximum walking distance (MWD) on treadmill tests after supervised exercise therapy (SET) in patients with symptomatic PAD. [10][11][12][13] Although home-based exercise has shown encouraging results, the magnitude of these results was inferior to SET. 14 According to the American Heart Association, the optimal SET modality still needs to be determined for patients with PAD. 15 Accumulating data indicate that other types of SET, such as Nordic walking, underwater exercise, and resistance training, could also be effective in improving walking capacity in patients with PAD. [16][17][18][19] Recently, a meta-analysis 8 suggested that other modes of exercise (without any distinction between them) could improve walking ability similar to supervised intermittent walking. Although this

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Background: Bladder cancer (BC) is one of the most common tumors of the male urogenital tract and an important worldwide cause of death. Increasing evidence has indicated the presence of cancer stem cells (CSCs) in many types of tumors, associated with aggressiveness, chemoresistance and relapse. The expression of inducible nitric oxide (NO) synthase (iNOS) in human BC is a poor prognostic factor associated with increased invasion and tumor recurrence. Although there is evidence supporting the role of NO/iNOS in the promotion and progression of BC, the possibility that there are CSCs dependent on endogenous NO generation was not yet been clearly defined. In this study we evaluate the role of NO in CSC maintenance, modulating its production, using pharmacological inhibitors or silencing iNOS expression in a murine BC model. Also, we analyzed the correlation between iNOS expression and stemness-related genes (SG) in human BC samples with different invasion grades. Methods: iNOS pharmacological inhibitors (pan-NOS or iNOS specific) or shRNA were used on murine BC model with different iNOS expression and invasiveness grade: MB49 [iNOS+, non-muscle invasive (NMI)] and MB49-I [iNOS++, muscle invasive (MI)], in order to analyze cell proliferation, number of CSC determined as spheres forming efficiency (SFE) and SG (Sox 2, Oct4 and Nanog expression) by qPCR. iNOS expression and SG were also analyzed in human BC samples (16 NMI low grade (LG), 10 NMI high grade (HG) and 17 MI). Results: The number of CSCs was higher in MB49-I than NMI MB49 line (p<0.05), in concordance with the higher expression of iNOS and Sox2, Oct4 and Nanog (p<0.001). iNOS inhibition diminished CSC in both cell lines (p<0.05 vs MB49; p<0.001 vs MB49-I). Inhibition of SG was only observed in MB49-I line (p<0.05). Moreover, the reduction of CSC and SG were more evident in MB49-I-shiNOS (p<0.0001 vs MB49-I scr; p<0.001 vs MB49-I-scr). The in vivo tumorigenic potential of cells derived from MB49-I spheres were higher than the cells growing in monolayers. MB49-I spheres cells treated with iNOS inhibitors did not developed tumors in vivo. Furthermore, MB49-I shiNOS spheres showed an incipient growth and regressed about 5 weeks post inoculation, in correlation with low iNOS and SG expression. Regarding human samples, iNOS was expressed in 78% of MI, 55% HG and 50% LGNMI (p<0.05 vs NMI). SG expression were significantly higher in MI than in NMI LG. Sox2 was expressed 82% in MI, 25% LG and 40% HG in NMI (p=0.0002). 76% of MI samples were positive for Nanog and Oct4 (p<0.05 vs NMI LG). A positive correlation between iNOS and SG expression was found (sox2: p<0.0001; Oct4: p<0.0001 and Nanog: p<0.05). Conclusion: Together, this results show that iNOS plays an important role in maintenance of CSC and in vivo BC growth by regulating stemness and self-renewal ability. Thus, iNOS identification and inhibition could be a potential target to eradicate CSC, responsible for tumor recurrences. Citation Format: Denise Belgorosky, Yanina Langle, Julie Girouard, Jovane Hamelin-Morrissette, Lina Marino, Eduardo I. Agüero, Héctor Malagrino, Carlos Reyes-Moreno, Ana M. Eiján. Relevance of iNOS expression in bladder cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3091.