PLA2-MjTX-II from Bothrops moojeni snake venom exhibits antimetastatic and antiangiogenic effects on human lung cancer cells.

Phospholipases A2 (PLA2s) from snake venom possess antitumor and antiangiogenic properties. In this study, we evaluated the antimetastatic and antiangiogenic effects of MjTX-II, a Lys49 PLA2 isolated from Bothrops moojeni venom, on lung cancer and endothelial cells. Using in vitro and ex vivo approaches, we demonstrated that MjTX-II reduced cell proliferation and inhibited fundamental processes for lung cancer cells (A549) growth and metastasis, such as adhesion, migration, invasion, and actin cytoskeleton decrease, without significantly interfering with non-tumorigenic lung cells (BEAS-2B). Furthermore, MjTX-II caused cell cycle alterations, increased reactive oxygen species production, modulated the expression of pro- and antiangiogenic genes, and decreased vascular endothelial growth factor (VEGF) expression in HUVECs. Finally, MjTX-II inhibited ex vivo angiogenesis processes in an aortic ring model. Therefore, we conclude that MjTX-II exhibits antimetastatic and antiangiogenic effects in vitro and ex vivo and represents a molecule that hold promise as a pharmacological model for antitumor therapy.

BjussuLAAO-II, an l-amino acid oxidase from Bothrops jararacussu snake venom, impairs Toxoplasma gondii infection in human trophoblast cells and villous explants from the third trimester of pregnancy.

One-third of the world's population is estimated to be affected by toxoplasmosis. Pregnancy-related Toxoplasma gondii infection can cause vertical transmission, infect the fetus, and cause miscarriage, stillbirth, and fetal death. The current study showed that both human trophoblast cells (BeWo lineage) and human explant villous were resistant to T. gondii infection after incubation with BjussuLAAO-II, an l-amino acid oxidase isolated from Bothrops jararacussu. Almost 90% of the parasite's ability to proliferate in BeWo cells was decreased by the toxin at 1.56 µg/mL and showed an irreversible anti-T. gondii effect. Also, BjussuLAAO-II impaired the key events of adhesion and invasion of T. gondii tachyzoites in BeWo cells. BjussuLAAO-II antiparasitic properties were associated with the intracellular production of reactive oxygen species and hydrogen peroxide, since the presence of catalase restored the parasite's growth and invasion. In addition, T. gondii growth in human villous explants was decreased to approximately 51% by the toxin treatment at 12.5 µg/mL. Furthermore, BjussuLAAO-II treatment altered IL-6, IL-8, IL-10 and MIF cytokines levels, assuming a pro-inflammatory profile in the control of T. gondii infection. This study contributes to the potential use of a snake venom l-amino acid oxidase for the development of agents against congenital toxoplasmosis and the discovery of new targets in parasites and host cells.

Phospholipase A2 Drives Tumorigenesis and Cancer Aggressiveness through Its Interaction with Annexin A1.

Phospholipids are suggested to drive tumorigenesis through their essential role in inflammation. Phospholipase A2 (PLA2) is a phospholipid metabolizing enzyme that releases free fatty acids, mostly arachidonic acid, and lysophospholipids, which contribute to the development of the tumor microenvironment (TME), promoting immune evasion, angiogenesis, tumor growth, and invasiveness. The mechanisms mediated by PLA2 are not fully understood, especially because an important inhibitory molecule, Annexin A1, is present in the TME but does not exert its action. Here, we will discuss how Annexin A1 in cancer does not inhibit PLA2 leading to both pro-inflammatory and pro-tumoral signaling pathways. Moreover, Annexin A1 promotes the release of cancer-derived exosomes, which also lead to the enrichment of PLA2 and COX-1 and COX-2 enzymes, contributing to TME formation. In this review, we aim to describe the role of PLA2 in the establishment of TME, focusing on cancer-derived exosomes, and modulatory activities of Annexin A1. Unraveling how these proteins interact in the cancer context can reveal new strategies for the treatment of different tumors. We will also describe the possible strategies to inhibit PLA2 and the approaches that could be used in order to resume the anti-PLA2 function of Annexin A1.

Stephalagine, an aporphine alkaloid from Annona crassiflora fruit peel, induces antinociceptive effects by TRPA1 and TRPV1 channels modulation in mice.

Pain relief represents a critical unresolved medical need. Consequently, the search for new analgesic agents is intensively studied. Annona crassiflora, a native species of the Brazilian Savanna, represents a potential source for painful treatment. This study aimed to investigate the antinociceptive potential of A. crassiflora fruit peel, focusing on its major alkaloid, stephalagine, in animal models of pain evoked by the activation of transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) channels. Male C57BL/6/J mice were submitted to formalin-, cinnamaldehyde-, and capsaicin-induced nociception tests to assess nociceptive behavior, and to the open-field and rotarod tests for motor performance analyses. Moreover, the stephalagine's effect was tested on capsaicin- and cinnamaldehyde-induced Ca2+ influx in spinal cord synaptosomes. In silico assessments of the absorption, distribution, metabolism and central nervous system permeability of stephalagine were carried out. The ethanol extract and alkaloidal fraction reduced the nociception induced by formalin. When administered by oral route (1 mg/kg), stephalagine reduced the spontaneous nociception and paw edema induced by TRPV1 agonist, capsaicin, and by TRPA1 agonists, cinnamaldehyde- and formalin, without altering the animals' locomotor activity. The prediction of in silico pharmacokinetic properties of stephalagine suggests its capacity to cross the blood-brain barrier. Furthermore, this alkaloid reduces the capsaicin- and cinnamaldehyde-mediated Ca2+ influx, indicating a possible modulation of TRPV1 and TRPA1 channels, respectively. Together, our results support the antinociceptive and anti-edematogenic effects of the A. crassiflora fruit peel and suggest that these effects are triggered, at least in part, by TRPV1 and TRPA1 modulation by stephalagine.

Inhibition of Triple-Negative Breast Cancer Cell Aggressiveness by Cathepsin D Blockage: Role of Annexin A1.

Triple-negative breast cancers (TNBCs) are more aggressive than other breast cancer (BC) subtypes and lack effective therapeutic options. Unraveling marker events of TNBCs may provide new directions for development of strategies for targeted TNBC therapy. Herein, we reported that Annexin A1 (AnxA1) and Cathepsin D (CatD) are highly expressed in MDA-MB-231 (TNBC lineage), compared to MCF-10A and MCF-7. Since the proposed concept was that CatD has protumorigenic activity associated with its ability to cleave AnxA1 (generating a 35.5 KDa fragment), we investigated this mechanism more deeply using the inhibitor of CatD, Pepstatin A (PepA). Fourier Transform Infrared (FTIR) spectroscopy demonstrated that PepA inhibits CatD activity by occupying its active site; the OH bond from PepA interacts with a CO bond from carboxylic acids of CatD catalytic aspartate dyad, favoring the deprotonation of Asp33 and consequently inhibiting CatD. Treatment of MDA-MB-231 cells with PepA induced apoptosis and autophagy processes while reducing the proliferation, invasion, and migration. Finally, in silico molecular docking demonstrated that the catalytic inhibition comprises Asp231 protonated and Asp33 deprotonated, proving all functional results obtained. Our findings elucidated critical CatD activity in TNBC cell trough AnxA1 cleavage, indicating the inhibition of CatD as a possible strategy for TNBC treatment.

Galectin-3: A Friend but Not a Foe during Trypanosoma cruzi Experimental Infection.

Trypanosoma cruzi interacts with host cells, including cardiomyocytes, and induces the production of cytokines, chemokines, metalloproteinases, and glycan-binding proteins. Among the glycan-binding proteins is Galectin-3 (Gal-3), which is upregulated after T. cruzi infection. Gal-3 is a member of the lectin family with affinity for ß-galactose containing molecules; it can be found in both the nucleus and the cytoplasm and can be either membrane-associated or secreted. This lectin is involved in several immunoregulatory and parasite infection process. Here, we explored the consequences of Gal-3 deficiency during acute and chronic T. cruzi experimental infection. Our results demonstrated that lack of Gal-3 enhanced in vitro replication of intracellular parasites, increased in vivo systemic parasitaemia, and reduced leukocyte recruitment. Moreover, we observed decreased secretion of pro-inflammatory cytokines in spleen and heart of infected Gal-3 knockout mice. Lack of Gal-3 also led to elevated mast cell recruitment and fibrosis of heart tissue. In conclusion, galectin-3 expression plays a pivotal role in controlling T. cruzi infection, preventing heart damage and fibrosis.

Mechanistic Insights into the Anti-angiogenic Activity of Trypanosoma cruzi Protein 21 and its Potential Impact on the Onset of Chagasic Cardiomyopathy.

Chronic chagasic cardiomyopathy (CCC) is arguably the most important form of the Chagas Disease, caused by the intracellular protozoan Trypanosoma cruzi; it is estimated that 10-30% of chronic patients develop this clinical manifestation. The most common and severe form of CCC can be related to ventricular abnormalities, such as heart failure, arrhythmias, heart blocks, thromboembolic events and sudden death. Therefore, in this study, we proposed to evaluate the anti-angiogenic activity of a recombinant protein from T. cruzi named P21 (rP21) and the potential impact of the native protein on CCC. Our data suggest that the anti-angiogenic activity of rP21 depends on the protein's direct interaction with the CXCR4 receptor. This capacity is likely related to the modulation of the expression of actin and angiogenesis-associated genes. Thus, our results indicate that T. cruzi P21 is an attractive target for the development of innovative therapeutic agents against CCC.

In vitro and in vivo antitumor effect of trachylobane-360, a diterpene from Xylopia langsdorffiana.

Trachylobane-360 (ent-7α-acetoxytrachyloban-18-oic acid) was isolated from Xylopia langsdorffiana. Studies have shown that it has weak cytotoxic activity against tumor and non-tumor cells. This study investigated the in vitro and in vivo antitumor effects of trachylobane-360, as well as its cytotoxicity in mouse erythrocytes. In order to evaluate the in vivo toxicological aspects related to trachylobane-360 administration, hematological, biochemical and histopathological analyses of the treated animals were performed. The compound exhibited a concentration-dependent effect in inducing hemolysis with HC50 of 273.6 µM, and a moderate in vitro concentration-dependent inhibitory effect on the proliferation of sarcoma 180 cells with IC50 values of 150.8 µM and 150.4 µM, evaluated by the trypan blue exclusion test and MTT reduction assay, respectively. The in vivo inhibition rates of sarcoma 180 tumor development were 45.60, 71.99 and 80.06% at doses of 12.5 and 25 mg/kg of trachylobane-360 and 25 mg/kg of 5-FU, respectively. Biochemical parameters were not altered. Leukopenia was observed after 5-FU treatment, but this effect was not seen with trachylobane-360 treatment. The histopathological analysis of liver and kidney showed that both organs were mildly affected by trachylobane-360 treatment. Trachylobane-360 showed no immunosuppressive effect. In conclusion, these data reinforce the anticancer potential of this natural diterpene.