Galectin-9 Triggers Neutrophil-Mediated Anticancer Immunity

In earlier studies, galectin-9 (Gal-9) was identified as a multifaceted player in both adaptive and innate immunity. Further, Gal-9 had direct cytotoxic and tumor-selective activity towards cancer cell lines of various origins. In the current study, we identified that treatment with Gal-9 triggered pronounced membrane alterations in cancer cells. Specifically, phosphatidyl serine (PS) was rapidly externalized, and the anti-phagocytic regulator, CD47, was downregulated within minutes. In line with this, treatment of mixed neutrophil/tumor cell cultures with Gal-9 triggered trogocytosis and augmented antibody-dependent cellular phagocytosis of cancer cells. Interestingly, this pro-trogocytic effect was also due to the Gal-9-mediated activation of neutrophils with upregulation of adhesion markers and mobilization of gelatinase, secretory, and specific granules. These activation events were accompanied by a decrease in cancer cell adhesion in mixed cultures of leukocytes and cancer cells. Further, prominent cytotoxicity was detected when leukocytes were mixed with pre-adhered cancer cells, which was abrogated when neutrophils were depleted. Taken together, Gal-9 treatment potently activated neutrophil-mediated anticancer immunity, resulting in the elimination of epithelial cancer cells.

719 XTX301, a protein-engineered IL-12, exhibits tumor-selective activity in mice without peripheral toxicities and is well tolerated in non-human primates

BackgroundInterleukin-12 (IL-12) is a proinflammatory cytokine which bridges innate and adaptive immunity via induction of T helper 1 differentiation and promoting cytolytic activity of natural killer and T cells. IL-12 has demonstrated potent antitumor activity in syngeneic mouse models and promising anti-tumor efficacy in humans. However, development of IL-12 has been limited by severe systemic toxicities. To overcome toxicity and improve the therapeutic index of IL-12, we employed protein engineering to generate XTX301, a highly potent, half-life extended and masked IL-12. The masking domain of XTX301 is designed to pharmacologically inactivate IL-12 systemically and render an active IL-12 moiety upon cleavage by proteases that are enriched in the tumor microenvironment.MethodsWe conducted experiments to assess the binding, bioactivity, safety, and anti-tumor efficacy of XTX301. Binding interactions were measured via SPR, bioactivity was measured using STAT-4 phosphorylation in a reporter cell line, and IFN-g production was assessed in human PBMCs via ELISA. Anti-tumor efficacy and pharmacodynamics were assessed in MC38 and B16F10 syngeneic tumor mouse models using a XTX301 murine surrogate, mXTX301. Safety and pharmacokinetics of XTX301 were evaluated in non-human primates (NHP).ResultsXTX301 showed no detectable binding to the high affinity IL12RB2 demonstrating that the masking domain indeed prevents interaction with the receptor. Upon cleavage of the masking domain by relevant proteases, binding was observed and was comparable to XTX300 unmasked control. Likewise, restoration of activity upon proteolytic cleavage was observed in an IL-12-dependent reporter gene assay and in primary human PBMCs. Human IL-12 does not cross react with mouse IL-12 receptors; hence a murine surrogate (mXTX301) was created for in vivo anti-tumor efficacy evaluation. A single dose of mXTX301 demonstrated up to 90% tumor growth inhibition in an inflamed MC38 and non-inflamed B16F10 syngeneic mouse models. mXTX301 induced a ~3 fold increase in IFN-g in tumors compared to vehicle control and ~150 fold less peripheral IFN-g compared to mXTX300. XTX301 exhibits minimal elevation in liver enzymes and a 50-fold improvement in tolerability compared to XTX300, in a repeat dose NHP safety study.ConclusionsOur data demonstrates that both XTX301 and mXTX301 are inactive when in masked form and become activated upon proteolytic cleavage to exert bioactivity comparable to recombinant IL-12. For efficacy, mXTX301 demonstrated tumor selective activity in syngeneic mouse models. XTX301 was well tolerated in repeat dose NHP safety study. In conclusion, XTX301 has potential for exerting potent anti-tumor activity with a favorable tolerability profile.

Welfare economics of managing an epidemic: an exposition

This paper reviews recent findings on the normative analysis of private and governmental countermeasures against infectious diseases, focusing on COVID-19. Based on a model that relates the economic activity to infectious disease epidemics, policies that maximize social welfare are considered. Lockdowns in many countries are measures that restrict economic activity over a wide area, and the economic damage they cause is extremely large. Existing studies on the net benefit of lockdown implemented in 2020 have reached mixed conclusions as to whether it is warranted or not. Although the estimates of costs and effects are relatively stable, the setting of the value of a statistical life for converting effects into benefits has a wide range and is also likely to overestimate benefits. Therefore, a careful procedure for setting is particularly crucial to obtain a reliable evaluation of countermeasures. Compared to uniform restriction of activities, taking measures to restrict activities by selecting targets may improve efficiency. Attributes that can be used to select targets include those that can be identified at little or no cost, such as age and industry, and those that can only be identified at a cost, such as close contact with infectious individuals and the presence of pathogens. In comparison to lockdown, these measures may reduce human suffering and economic suffering. No trade-off exists between uniform activity restrictions and selective activity restrictions.

Nostocyclopeptides as New Inhibitors of 20S Proteasome

Nostocyclopeptides (Ncps) are a small class of bioactive nonribosomal peptides produced solely by cyanobacteria of the genus Nostoc. In the current work, six Ncps were isolated from Nostoc edaphicum strain CCNP1411. The bioactivity of these compounds was tested in vitro against 20S proteasome, a proteolytic complex that plays an important role in maintaining cellular proteostasis. Dysfunction of the complex leads to many pathological disorders. The assays indicated selective activity of specific Ncp variants. For two linear peptide aldehydes, Ncp-A2-L and Ncp-E2-L, the inhibitory effects on chymotrypsin-like activity were revealed, while the cyclic variant, Ncp-A2, inactivated the trypsin-like site of this enzymatic complex. The aldehyde group was confirmed to be an important element of the chymotrypsin-like activity inhibitors. The nostocyclopeptides, as novel inhibitors of 20S proteasome, increased the number of natural products that can be considered potential regulators of cellular processes.

Tumor-selective activity of XTX202, a protein-engineered IL-2, in mice without peripheral toxicities in nonhuman primates.

2563 Background: High-dose recombinant human interleukin-2 (aldesleukin) elicits anti-tumor immunity and is approved for the treatment of renal cell carcinoma and melanoma based on durable complete remissions. However, use of aldesleukin is limited due to treatment-related life-threatening toxicities. Recent second-generation efforts to alleviate toxicities have largely focused on eliminating binding to IL-2Rα, often with half-life extension. We have determined that mice and non-human primates (NHPs) treated with a second generation IL-2 surrogate still experience characteristic dose-limiting toxicities, including vascular leak syndrome. To overcome these toxicities and improve the therapeutic index (TI) of IL-2 as an anti-tumor immunotherapy, we employed protein engineering to generate XTX202, a highly potent third generation masked IL-2. XTX202 is unmasked in the tumor microenvironment by proteolytic activation resulting in full restoration of binding to IL-2Rβ without binding to IL-2Rα. The current study characterizes the therapeutic index of XTX202 versus aldesleukin and a second generation IL-2 surrogate. Methods: XTX202 bioactivity was measured using STAT-5 phosphorylation in human PBMCs and reporter cell lines. Anti-tumor efficacy and peripheral immune activation were evaluated in mice bearing syngeneic tumor models. Safety was evaluated in rodents and Cynomolgus monkeys. XTX200, an unmasked half-life extended IL-2 that does not bind to IL-2Rα, was used as a surrogate second generation IL-2. Results: Masked XTX202 showed limited IL-2R-dependent STAT-5 signaling in vitro. Proteolytic activation of XTX202 resulted in CD8+ T and NK cell activation and over 1000-fold reduction in Treg activation as compared to WT IL-2. XTX202 achieved potent tumor growth inhibition in syngeneic mouse models as a single agent with no evidence of toxicity or peripheral immune activation, thus demonstrating tumor selective activity. XTX202 efficacy in mice at 2 mg/kg dose was equivalent to that achieved with the MTD dose of 0.5 mg/kg of a second generation IL-2 surrogate. XTX202 was well tolerated in NHPs in a 4-week repeat dose study at doses up to 30 mg/kg QW whereas a second generation IL-2 surrogate was not tolerated beyond 0.7 mg/kg QW. Based on these data, XTX202 has a 10 fold improvement in TI vs second generation IL-2. Based on comparative efficacy studies with aldesleukin and literature NHP tolerability data, XTX202 is projected to have a ≥150 fold greater TI than aldesleukin. Conclusions: XTX202, a third generation, tumor-selective IL-2, inhibits tumor growth and is well tolerated in repeat dose studies in NHPs at high doses. GLP toxicity studies with XTX202 are underway and first-in-human studies are expected to initiate this year. XTX202 has the potential to be a best-in-class IL-2 immunotherapy by expanding the curative anti-tumor activity of IL-2 while minimizing dose-limiting toxicities.

Topic relevance as the basic structuration of the field of consciousness

My aim is to depict Schutz's theory of topic relevance as his own distinctive phenomenology of consciousness. I will show that his conception of consciousness is elaborated from at least three types of elements. First, I will disclose Husserl's influence on Schutz in this matter. I will list a few Husserlian terms that Schutz takes into consideration such as noema, horizon, parts and wholes, attentional ray and passive synthesis. Second, I will show that Schutz turns to Gurwitsch's idea that consciousness is a field of experience where the previously listed elements are held together and find their relational meaning. Third, I will expose how all these elements taken from Husserl and Gurwitsch are reinterpreted by Schutz as being relative to relevance as a basic phenomenon of our mind's selective activity which puts at work different levels of our personality according to the schizophrenic ego hypothesis.

Cytotoxicity assessment of beta-lapachone in endothelial cells

The selective activity of an antineoplastic drug is related to its ability to promote cytotoxic action on tumor cells and preserve the integrity of non-neoplastic cells. Beta-lapachone is extracted from the sawdust of Ipe wood, a thick bark tree from the Ipe wood found in the Brazilian Cerrado biome. This study aimed to evaluate the cytotoxic action of beta-lapachone in an endothelial cell line. The EA.hy926 cells were seeded in two groups, G1 and G2, cultured and exposed to beta-lapachone at concentrations of 0.0, 0.01, 0.03, 0.1, 0.3, 1 and 3 μM for 24 hours. G1 remained under normal cultivation conditions and G2 was subjected to oxidative stress through an ischemia and reperfusion assay, in a deoxygenated sealed chamber. The cytotoxicity assay was performed using the tetrazolium reduction method. In G1, the cytotoxicity ranged from 0.0 to 10.0%; and in G2 between 0.0 and 6.3%. No statistically significant difference was observed between the obtained values. Moreover, we found no cytotoxic action of beta-lapachone on endothelial cells, and the results point out that the drug might have preserved the cell’s integrity against oxidative stress under the conditions of this experiment. This promising result suggests the possibility of beta-lapachone as a chemotherapy drug with selective activity.

Magnificines A and B, Antimicrobial Marine Alkaloids Featuring a Tetrahydrooxazolo[3,2-a]azepine-2,5(3H,6H)-dione Backbone from the Red Sea Sponge Negombata magnifica

Investigation of the Red Sea sponge Negombata magnifica gave two novel alkaloids, magnificines A and B (1 and 2) and a new β-ionone derivative, (±)-negombaionone (3), together with the known latrunculin B (4) and 16-epi-latrunculin B (5). The analysis of the NMR and HRESIMS spectra supported the planar structures and the relative configurations of the compounds. The absolute configurations of magnificines A and B were determined by the analysis of the predicted and experimental ECD spectra. Magnificines A and B possess a previously unreported tetrahydrooxazolo[3,2-a]azepine-2,5(3H,6H)-dione backbone and represent the first natural compounds in this class. (±)-Negombaionone is the first β-ionone of a sponge origin. Compounds 1-3 displayed selective activity against Escherichia coli in a disk diffusion assay with inhibition zones up to 22 mm at a concentration of 50 µg/disc and with MIC values down to 8.0 µM. Latrunculin B and 16-epi-latrunculin B inhibited the growth of HeLa cells with IC50 values down to 1.4 µM.