Antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, on Leishmania (Leishmania) amazonensis.

BACKGROUND: Leishmaniasis, a neglected disease caused by the parasite Leishmania, is treated with drugs associated with high toxicity and limited efficacy, in addition to constant reports of the emergence of resistant parasites. In this context, snake serums emerge as good candidates since they are natural sources with the potential to yield novel drugs. OBJECTIVES: We aimed to show the antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, against Leishmania (Leishmania) amazonensis. METHODS: Promastigotes forms were exposed to γCdcPLI, and we assessed the parasite viability and cell cycle, as well as invasion and proliferation assays. FINDINGS: Despite the low cytotoxicity effect on macrophages, our data indicate that γCdcPLI has a direct effect on parasites promoting an arrest in the G1 phase and reduction in the G2/M phase at the highest dose tested. Moreover, this PLA2 inhibitor reduced the parasite infectivity when promastigotes were pre-treated. Also, we demonstrated that the γCdcPLI treatment modulated the host cell environment impairing early and late steps of the parasitism. MAIN CONCLUSIONS: γCdcPLI is an interesting tool for the discovery of new essential targets on the parasite, as well as an alternative compound to improve the effectiveness of the leishmaniasis treatment.

Antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, on Leishmania (Leishmania) amazonensis

BACKGROUND Leishmaniasis, a neglected disease caused by the parasite Leishmania, is treated with drugs associated with high toxicity and limited efficacy, in addition to constant reports of the emergence of resistant parasites. In this context, snake serums emerge as good candidates since they are natural sources with the potential to yield novel drugs. OBJECTIVES We aimed to show the antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, against Leishmania (Leishmania) amazonensis. METHODS Promastigotes forms were exposed to γCdcPLI, and we assessed the parasite viability and cell cycle, as well as invasion and proliferation assays. FINDINGS Despite the low cytotoxicity effect on macrophages, our data indicate that γCdcPLI has a direct effect on parasites promoting an arrest in the G1 phase and reduction in the G2/M phase at the highest dose tested. Moreover, this PLA2 inhibitor reduced the parasite infectivity when promastigotes were pre-treated. Also, we demonstrated that the γCdcPLI treatment modulated the host cell environment impairing early and late steps of the parasitism. MAIN CONCLUSIONS γCdcPLI is an interesting tool for the discovery of new essential targets on the parasite, as well as an alternative compound to improve the effectiveness of the leishmaniasis treatment.

Shedding Lights on Crude Venom from Solitary Foraging Predatory Ant Ectatomma opaciventre: Initial Toxinological Investigation.

Some species of primitive predatory ants, despite living in a colony, exercise their hunting collection strategy individually; their venom is painful, paralyzing, digestive, and lethal for their prey, yet the toxins responsible for these effects are poorly known. Ectatomma opaciventre is a previously unrecorded solitary hunting ant from the Brazilian Cerrado. To overcome this hindrance, the present study performed the in vitro enzymatic, biochemical, and biological activities of E. opaciventre to better understand the properties of this venom. Its venom showed several proteins with masses ranging from 1-116 kDa, highlighting the complexity of this venom. Compounds with high enzymatic activity were described, elucidating different enzyme classes present in the venom, with the presence of the first L-amino acid oxidase in Hymenoptera venoms being reported. Its crude venom contributes to a state of blood incoagulability, acting on primary hemostasis, inhibiting collagen-induced platelet aggregation, and operating on the fibrinolysis of loose red clots. Furthermore, the E. opaciventre venom preferentially induced cytotoxic effects on lung cancer cell lines and three different species of Leishmania. These data shed a comprehensive portrait of enzymatic components, biochemical and biological effects in vitro, opening perspectives for bio-pharmacological application of E. opaciventre venom molecules.

Shedding lights on crude venom from solitary foraging predatory ant Ectatomma opaciventre: initial toxinological investigation

Some species of primitive predatory ants, despite living in a colony, exercise their hunting collection strategy individually; their venom is painful, paralyzing, digestive, and lethal for their prey, yet the toxins responsible for these effects are poorly known. Ectatomma opaciventre is a previously unrecorded solitary hunting ant from the Brazilian Cerrado. To overcome this hindrance, the present study performed the in vitro enzymatic, biochemical, and biological activities of E. opaciventre to better understand the properties of this venom. Its venom showed several proteins with masses ranging from 1–116 kDa, highlighting the complexity of this venom. Compounds with high enzymatic activity were described, elucidating different enzyme classes present in the venom, with the presence of the first L-amino acid oxidase in Hymenoptera venoms being reported. Its crude venom contributes to a state of blood incoagulability, acting on primary hemostasis, inhibiting collagen-induced platelet aggregation, and operating on the fibrinolysis of loose red clots. Furthermore, the E. opaciventre venom preferentially induced cytotoxic effects on lung cancer cell lines and three different species of Leishmania. These data shed a comprehensive portrait of enzymatic components, biochemical and biological effects in vitro, opening perspectives for bio-pharmacological application of E. opaciventre venom molecules.

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.

Action of copper(II) complex with ß-diketone and 1,10-phenanthroline (CBP-01) on sarcoma cells and biological effects under cell death.

This work reports the biological evaluation of a copper complex of the type [Cu(O-O)(N-N)ClO4], in which O-O = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbta) and N-N = 1,10-phenanthroline (phen), whose generic name is CBP-01. The cytotoxic effect of CBP-01 was evaluated by resazurin assay and cell proliferation was determined by MTT assay. DNA fragmentation was analyzed by gel electrophoresis. Cell cycle progression was detected through propidium iodide (PI) staining. Apoptosis and autophagy were determined by, respectively, Annexin V and 7-AAD staining and monodansylcadaverine (MDC) staining. The changes in intracellular reactive oxygen species levels were detected by DCFDA analysis. The copper complex CBP-01 showed in vitro antitumor activity with IC50s values of 7.4 µM against Sarcoma 180 and 26.4 against murine myoblast cells, displaying selectivity toward the tumor cell tested in vitro (SI > 3). An increase in reactive oxygen species (ROS) generation was observed, which may be related to the action mechanism of the complex. The complex CBP-01 may induce DNA damage leading cells to accumulate at G0/G1 checkpoint where, apparently, cells that are not able to recover from the damage are driven to cell death. Evidence has shown that cell death is initiated by autophagy dysfunction, culminating in apoptosis induction. The search for new metal-based drugs is focused on overcoming the drawbacks of already used agents such as acquired resistance and non-specificity; thus, the results obtained with CBP-01 show promising effects on cancer cells.

Action of copper(II) complex with ß-diketone and 1,10-phenanthroline (CBP-01) on sarcoma cells and biological effects under cell death

This work reports the biological evaluation of a copper complex of the type [Cu(O–O)(N–N)ClO4], in whichO–O = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbta) and N–N = 1,10-phenanthroline (phen), whose genericname is CBP-01. The cytotoxic effect of CBP-01 was evaluated by resazurin assay and cell proliferation wasdetermined by MTT assay. DNA fragmentation was analyzed by gel electrophoresis. Cell cycle progression wasdetected through propidium iodide (PI) staining. Apoptosis and autophagy were determined by, respectively,Annexin V and 7-AAD staining and monodansylcadaverine (MDC) staining. The changes in intracellular reactiveoxygen species levels were detected by DCFDA analysis. The copper complex CBP-01 showed in vitro antitumoractivity with IC50s values of 7.4µM against Sarcoma 180 and 26.4 against murine myoblast cells, displayingselectivity toward the tumor cell tested in vitro (SI > 3). An increase in reactive oxygen species (ROS) gen-eration was observed, which may be related to the action mechanism of the complex. The complex CBP-01 mayinduce DNA damage leading cells to accumulate at G0/G1 checkpoint where, apparently, cells that are not ableto recover from the damage are driven to cell death. Evidence has shown that cell death is initiated by autophagydysfunction, culminating in apoptosis induction. The search for new metal-based drugs is focused on overcomingthe drawbacks of already used agents such as acquired resistance and non-specificity; thus, the results obtainedwith CBP-01 show promising effects on cancer cells.

Action of copper(II) complex with ß-diketone and 1,10-phenanthroline (CBP-01) on sarcoma cells and biological effects under cell death

This work reports the biological evaluation of a copper complex of the type [Cu(O–O)(N–N)ClO4], in whichO–O = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbta) and N–N = 1,10-phenanthroline (phen), whose genericname is CBP-01. The cytotoxic effect of CBP-01 was evaluated by resazurin assay and cell proliferation wasdetermined by MTT assay. DNA fragmentation was analyzed by gel electrophoresis. Cell cycle progression wasdetected through propidium iodide (PI) staining. Apoptosis and autophagy were determined by, respectively,Annexin V and 7-AAD staining and monodansylcadaverine (MDC) staining. The changes in intracellular reactiveoxygen species levels were detected by DCFDA analysis. The copper complex CBP-01 showed in vitro antitumoractivity with IC50s values of 7.4µM against Sarcoma 180 and 26.4 against murine myoblast cells, displayingselectivity toward the tumor cell tested in vitro (SI > 3). An increase in reactive oxygen species (ROS) gen-eration was observed, which may be related to the action mechanism of the complex. The complex CBP-01 mayinduce DNA damage leading cells to accumulate at G0/G1 checkpoint where, apparently, cells that are not ableto recover from the damage are driven to cell death. Evidence has shown that cell death is initiated by autophagydysfunction, culminating in apoptosis induction. The search for new metal-based drugs is focused on overcomingthe drawbacks of already used agents such as acquired resistance and non-specificity; thus, the results obtainedwith CBP-01 show promising effects on cancer cells.