An improved colorimetric assay for interleukin 2

Multitarget anti-parasitic activities of isoquinoline alkaloids isolated from Hippeastrum aulicum (Amaryllidaceae)

BACKGROUND

Chagas disease and leishmaniasis affect a significant portion of the Latin American population and still lack efficient treatments. In this context, natural products emerge as promising compounds for developing more effective therapies, aiming to mitigate side effects and drug resistance. Notably, species from the Amaryllidaceae family emerge as potential reservoirs of antiparasitic agents due to the presence of diverse biologically active alkaloids.

PURPOSE

To assess the anti-Trypanosoma cruzi and anti-Leishmania infantum activity of five isolated alkaloids from Hippeastrum aulicum Herb. (Amaryllidaceae) against different life stages of the parasites using in silico and in vitro assays. Furthermore, molecular docking was employed to evaluate the interaction of the most active alkaloids.

METHODS

Five natural isoquinoline alkaloids isolated in suitable quantities for in vitro testing underwent preliminary in silico analysis to predict their potential efficacy against Trypanosoma cruzi (amastigote and trypomastigote forms) and Leishmania infantum (amastigote and promastigote forms). The in vitro antiparasitic activity and mammalian cytotoxicity were investigated with a subsequent comparison of both analysis (in silico and in vitro) findings. Additionally, this study employed the molecular docking technique, utilizing cruzain (T. cruzi) and sterol 14α-demethylase (CYP51, L. infantum) as crucial biological targets for parasite survival, specifically focusing on compounds that exhibited promising activities against both parasites.

RESULTS

Through computational techniques, it was identified that the alkaloids haemanthamine (1) and lycorine (8) were the most active against T. cruzi (amastigote and trypomastigote) and L. infantum (amastigote and promastigote), while also revealing unprecedented activity of alkaloid 7‑methoxy-O-methyllycorenine (6). The in vitro analysis confirmed the in silico tests, in which compound 1 presented the best activities against the promastigote and amastigote forms of L. infantum with half-maximal inhibitory concentration (IC50) 0.6 µM and 1.78 µM, respectively. Compound 8 exhibited significant activity against the amastigote form of T. cruzi (IC50 7.70 µM), and compound 6 demonstrated activity against the trypomastigote forms of T. cruzi and amastigote of L. infantum, with IC50 values of 89.55 and 86.12 µM, respectively. Molecular docking analyses indicated that alkaloids 1 and 8 exhibited superior interaction energies compared to the inhibitors.

CONCLUSION

The hitherto unreported potential of compound 6 against T. cruzi trypomastigotes and L. infantum amastigotes is now brought to the forefront. Furthermore, the acquired dataset signifies that the isolated alkaloids 1 and 8 from H. aulicum might serve as prototypes for subsequent structural refinements aimed at the exploration of novel leads against both T. cruzi and L. infantum parasites.

A near-infrared emitting "off-on" fluorescent probe for bioimaging of Pd(Ⅱ) ions in living cells and mice

BACKGROUND

The surging consumption of palladium in modern industry has given rise to its accumulation in the ecosystem, posing conspicuous toxicity to aquatic organisms and human health. The investigation of palladium in biological systems is highly demanded for the in-depth understanding of its dynamics and behaviors. Fluorescence imaging serves as a powerful approach to assess palladium species in biological systems, and currently most of the sensing probes are applicable to living cells. Effective tracking of palladium species in living organisms is challenging, which requires sufficient hydrophilicity and imaging depth of the probes.

RESULTS

Based on an intramolecular charge transfer (ICT) mechanism, a distyryl boron dipyrromethene (BODIPY) derivative (DISBDP-Pd) has been prepared for the near-infrared (NIR) fluorescence imaging of Pd2+ ions. Two additional methoxy triethylene glycol (TEG) chains could serve as flexible and hydrophilic moieties to enhance the aqueous solubility and cell permeability of the extended conjugate. Solution studies revealed that DISBDP-Pd exhibited a NIR fluorescence enhancement signal exclusively to Pd2+ ions (detection limit as low as 0.85 ppb) with negligible interference from Pd0 species and other closely related metal ions. Computational calculations have been performed to rationalize the binding mode and the mechanism of action. Fluorescence imaging assays have been conducted on A549 human non-small cell lung carcinoma cells and mouse models. Exhibiting negligible cytotoxicity, DISBDP-Pd demonstrated concentration-related fluorescence enhancement signals in response to Pd2+ ions in living cells and mice.

SIGNIFICANCE

DISBDP-Pd exhibits advantages over many small molecule palladium probes in terms of satisfactory aqueous solubility, high sensitivity and selectivity, and biocompatible NIR emission property, which are particularly favorable for the sensing application in biological environments. The design strategy of this probe can potentially be adopted for the functionalization of other BODIPY probes implemented for NIR fluorescence bioimaging.

In Vitro and In Vivo Anti-Cancer Activity of Lasiokaurin in a Triple-Negative Breast Cancer Model

Due to its intricate heterogeneity, high invasiveness, and poor prognosis, triple-negative breast cancer (TNBC) stands out as the most formidable subtype of breast cancer. At present, chemotherapy remains the prevailing treatment modality for TNBC, primarily due to its lack of estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal growth receptor 2 (HER2). However, clinical chemotherapy for TNBC is marked by its limited efficacy and a pronounced incidence of adverse effects. Consequently, there is a pressing need for novel drugs to treat TNBC. Given the rich repository of diverse natural compounds in traditional Chinese medicine, identifying potential anti-TNBC agents is a viable strategy. This study investigated lasiokaurin (LAS), a natural diterpenoid abundantly present in Isodon plants, revealing its significant anti-TNBC activity both in vitro and in vivo. Notably, LAS treatment induced cell cycle arrest, apoptosis, and DNA damage in TNBC cells, while concurrently inhibiting cell metastasis. In addition, LAS effectively inhibited the activation of the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway and signal transducer and activator of transcription 3 (STAT3), thus establishing its potential for multitarget therapy against TNBC. Furthermore, LAS demonstrated its ability to reduce tumor growth in a xenograft mouse model without exerting detrimental effects on the body weight or vital organs, confirming its safe applicability for TNBC treatment. Overall, this study shows that LAS is a potent candidate for treating TNBC.

Targeting sphingosine kinase 1 in p53KO thymic lymphoma

Sphingosine kinase 1 (SK1) is a key sphingolipid enzyme that is upregulated in several types of cancer, including lymphoma which is a heterogenous group of malignancies. Treatment for lymphoma has improved significantly by the introduction of new therapies; however, subtypes with tumor protein P53 (p53) mutations or deletion have poor prognosis, making it critical to explore new therapeutic strategies in this context. SK1 has been proposed as a therapeutic target in different types of cancer; however, the effect of targeting SK1 in cancers with p53 deletion has not been evaluated yet. Previous work from our group suggests that loss of SK1 is a key event in mediating the tumor suppressive effect of p53. Employing both genetic and pharmacological approaches to inhibit SK1 function in Trp53KO mice, we show that targeting SK1 decreases tumor growth of established p53KO thymic lymphoma. Inducible deletion of Sphk1 or its pharmacological inhibition drive increased cell death in tumors which is accompanied by selective accumulation of sphingosine levels. These results demonstrate the relevance of SK1 in the growth and maintenance of lymphoma in the absence of p53 function, positioning this enzyme as a potential therapeutic target for the treatment of tumors that lack functional p53.

Molecular basis for nuclear accumulation and targeting of the inhibitor of apoptosis BIRC2

The inhibitor of apoptosis protein BIRC2 regulates fundamental cell death and survival signaling pathways. Here we show that BIRC2 accumulates in the nucleus via binding of its second and third BIR domains, BIRC2BIR2 and BIRC2BIR3, to the histone H3 tail and report the structure of the BIRC2BIR3-H3 complex. RNA-seq analysis reveals that the genes involved in interferon and defense response signaling and cell-cycle regulation are most affected by depletion of BIRC2. Overexpression of BIRC2 delays DNA damage repair and recovery of the cell-cycle progression. We describe the structural mechanism for targeting of BIRC2BIR3 by a potent but biochemically uncharacterized small molecule inhibitor LCL161 and demonstrate that LCL161 disrupts the association of endogenous BIRC2 with H3 and stimulates cell death in cancer cells. We further show that LCL161 mediates degradation of BIRC2 in human immunodeficiency virus type 1-infected human CD4+ T cells. Our findings provide mechanistic insights into the nuclear accumulation of and blocking BIRC2.

Biological activity and structure-activity relationship of dehydrodieugenol B analogues against visceral leishmaniasis

Visceral leishmaniasis is a neglected protozoan disease with high mortality. Existing treatments exhibit a number of limitations, resulting in a significant challenge for public health, especially in developing countries in which the disease is endemic. With a limited pipeline of potential drugs in clinical trials, natural products could offer an attractive source of new pharmaceutical prototypes, not least due to their high chemodiversity. In the present work, a study of anti-L. (L.) infantum potential was carried out for a series of 39 synthetic compounds based on the core scaffold of the neolignan dehydrodieugenol B. Of these, 14 compounds exhibited activity against intracellular amastigotes, with 50% inhibitory concentration (IC₅₀) values between 3.0 and 32.7 μM. A structure-activity relationship (SAR) analysis demonstrated a requirement for polar functionalities to improve activity. Lacking mammalian cytotoxicity and presenting the highest potency against the clinically relevant form of the parasite, compound 24 emerged as the most promising, fulfilling the hit criteria for visceral leishmaniasis defined by the Drugs for Neglected Diseases initiative (DNDi). This study emphasizes the potential of dehydrodieugenol B analogues as new candidates for the treatment of visceral leishmaniasis and suggests 24 to be a suitable compound for future optimization, including mechanism of action and pharmacokinetic studies.

Piperazine amides with desirable solubility, physicochemical and drug-like properties: Synthesis and evaluation of the anti-Trypanosoma cruzi activity

The absence of effective chronic treatment, expansion to non-endemic countries and the significant burden in public health have stimulated the search for novel therapeutic options to treat Chagas disease, a protozoan disease caused by Trypanosoma cruzi. Despite current efforts, no new drug candidates were approved in clinical trials in the past five decades. Considering this, our group has focused on the expansion of a series (LINS03) with low micromolar activity against amastigotes, considering the optimization of pharmacokinetic properties through increasing drug-likeness and solubility. In this work, we report a new set of 13 compounds with modifications in both the arylpiperazine and the aromatic region linked by an amide group. Five analogues showed activity against intracellular amastigotes (IC₅₀ 17.8 to 35.9 µM) and no relevant cytotoxicity to mammalian cells (CC₅₀ > 200 µM). Principal component analysis (PCA) was performed to identify structural features associated to improved activity. The data revealed that polarity, hydrogen bonding ability and flexibility were key properties that influenced the antiparasitic activity. In silico drug-likeness assessments indicated that compounds with the 4-methoxycinammyl (especially compound 2b) had the most prominent balance between properties and activity in the series, as confirmed by SAR analysis.

Effects on cell cycle progression and cytoskeleton organization of five Bothrops spp. venoms in cell culture-based assays

Snake envenomation is a neglected tropical disease. In Brazil, the Bothrops genus is responsible for about 86% of snakebite accidents. Despite extensive evidence of the cytotoxicity of snake venoms, the cellular and molecular mechanisms involved are not fully understood, especially regarding the effects on cell cycle progression and cytoskeleton organization. Traditionally, the effectiveness and quality control tests of venoms and antivenoms are assessed by in vivo assays. Despite this, there is a rising effort to develop surrogate in vitro models according to the 3R principle (Replacement, Reduction, and Refinement). In this study, we treated rat liver cells (BRL-3A) with venoms from five Bothrops species (B. jararaca, B. jararacussu, B. moojeni, B. alternatus, and B. neuwiedi) and analyzed cell viability and IC50 by MTT assay, cell cycle phases distribution by flow cytometry, and morphology and cytoskeleton alterations by immunofluorescence. In addition, we evaluated the correlation between IC50 and the enzymatic and biological activities of each venom. Our results indicated that Bothrops spp. venoms decreased the cell viability of rat liver BRL-3A cells. The rank order of potency was B. jararacussu > B. moojeni > B. alternatus > B. jararaca > B. neuwiedi. The mechanisms of cytotoxicity were related to microtubules and actin network disruption, but not to cell cycle arrest. No clear correlation was found between the IC50 and retrieved literature data of in vitro enzymatic and in vivo biological activities. This work contributed to understanding cellular and molecular mechanisms underlying the Bothrops spp. venom cytotoxicity, which can help to improve envenomation treatment, as well as disclose potential therapeutic properties of snake venoms.

Production and Characterisation of an Exopolysaccharide by Bacillus amyloliquefaciens: Biotechnological Applications

The Bacillus amyloliquefaciens RT7 strain was isolated from an extreme acidic environment and identified. The biodegradation capabilities of the strain using different carbon sources (glucose, oleic acid, Tween 80, PEG 200, and the combination of glucose-Tween 80) were evaluated via an indirect impedance technique. The glucose-Tween 80 combination was further studied using nuclear magnetic resonance (NMR). The exopolysaccharide (EPS_RT7) that had been produced with the strain when biodegrading glucose-Tween 80 was isolated and characterised using different techniques (GC-MS, HPLC/MSMS, ATR-FTIR, TGA, and DSC), and its molecular weight was estimated. The results show that the average molecular weight of EPS_RT7 was approximately 7.0794 × 10⁴ Da and a heteropolysaccharide composed of mannose, glucose, galactose, and xylose (molar ratio, 1:0.5:0.1:0.1) with good thermostability. EPS_RT7 showed good emulsifying activity against different natural oils and hydrocarbons at high concentrations (2 mg/mL) and at the studied pH range (3.1-7.2). It also presented good emulsifying activity compared to that of commercial emulsifiers. Lastly, EPS_RT7 showed antioxidant capacity for different free radicals, a lack of cytotoxicity, and antioxidant activity at the cellular level. EPS_RT7 has promising applications in bioremediation processes and other industrial applications.

Synthesis, Cellular Uptake, and Photodynamic Activity of Oligogalactosyl Zinc(II) Phthalocyanines

A series of di-α-substituted zinc(II) phthalocyanines with different number of galactose moieties, ranging from 1 to 8, namely Pc-gal_n (n=1, 2, 4, and 8) were designed and synthesized. The synthesis involved the copper-catalyzed azide-alkyne cycloaddition reaction of a mono- or dialkynyl zinc(II) phthalocyanine with an acetyl-protected galactosyl azide or its dendritic derivative with four acetyl-protected galactosyl groups, followed by removal of the acetyl protecting groups via alkaline hydrolysis. In N,N-dimethylformamide, these oligogalactosyl phthalocyanines were non-aggregated as shown by the strong Q-band absorption and fluorescence emission. Owing to the di-α-substitution, they also behaved as efficient singlet oxygen generators upon light irradiation with a singlet oxygen quantum yield of 0.84. The spectroscopic and photophysical properties were not affected by the number of galactosyl units. In contrast, the compounds became significantly aggregated and quenched in phosphate-buffered saline. Their cellular uptake was then studied using a range of cell lines, which generally followed the order Pc-gal₁ >Pc-gal₂ ≈Pc-gal₄ >Pc-gal₈ . Interestingly, the di-galactosyl analogue exhibited selective uptake against HeLa human cervical carcinoma cells through an energy-dependent pathway instead of the expected asialoglycoprotein receptor. Upon light irradiation, it could effectively kill the cells with a half-maximal inhibitory concentration of 0.58 μM.

Phytochemical study and immunomodulatory activity of Fraxinus excelsior L

OBJECTIVES

Fraxinus excelsior L. (FE) is traditionally used to treat inflammatory and pain disorders. This study aimed to identify the constituents of FE leaves and evaluate the effects of its n-hexane (FEH), ethyl acetate (FEE), methanol (FEM) extracts and constituents on the viability of THP-1 cells and their ability to release pro-inflammatory cytokines.

METHODS

THP-1 cell viability was assessed using an MTT assay. The immunomodulatory activity was evaluated by measuring tumour necrosis factor-alpha (TNF-α) and interleukin 12 (IL-12) released by lipopolysaccharide-stimulated THP-1 cells using enzyme-linked immunosorbent assays.

KEY FINDINGS

Triterpenes, tyrosol esters, alkanes, phytyl and steryl esters, pinocembrin and bis(2-ethylhexyl)phthalate were isolated from FE. The tyrosol esters showed no significant effect on THP-1 cell viability. FEH, FEE, FEM, and pinocembrin, ursolic acid, oleanolic acid had IC50 values of 56.9, 39.9, 124.7 µg/ml and 178.6, 61.5 and 199.8 µM, respectively. FE extracts, ursolic acid, oleanolic acid and pinocembrin significantly reduced TNF-α/IL-12 levels. The tyrosol esters did not significantly affect TNF-α/IL-12 production.

CONCLUSIONS

FE was able to reduce pro-inflammatory cytokine production indicating a mechanistic focus in its use for inflammation and pain. Further investigations are warranted to unravel the mode of action of the tested constituents and discover other potentially active compounds in FE extracts.

Lethal action of Licarin A derivatives in Leishmania (L.) infantum: Imbalance of calcium and bioenergetic metabolism

Natural metabolites present an extraordinary chemo-diversity and have been used as the inspiration for new drugs. Considering the need for new treatments against the neglected parasitic disease leishmaniasis, three semi-synthetic derivatives of natural neolignane licarin A were prepared: O-acetyl (1a), O-allyl (1b), and 5-allyl (1c). Using an ex vivo assay, compounds 1a, 1b, and 1c showed activity against the intracellular amastigotes of Leishmania (L.) infantum, with IC₅₀ values of 9, 13, and 10 μM, respectively. Despite no induction of hemolytic activity, only compound 1b resulted in mammalian cytotoxicity (CC₅₀ = 64 μM). The most potent compounds (1a and 1c) resulted in selectivity indexes >18. The mechanism of action of compound 1c was evaluated by fluorescent/luminescent based techniques and MALDI-TOF/MS. After a short incubation period, increased levels of the cytosolic calcium were observed in the parasites, with alkalinization of the acidocalcisomes. Compound 1c also induced mitochondrial hyperpolarization, resulting in decreased levels of ATP without altering the reactive oxygen species (ROS). Neither plasma membrane damages nor DNA fragmentation were observed after the treatment, but a reduction in the cellular proliferation was detected. Using MALDI-TOF/MS, mass spectral alterations of promastigote proteins were observed when compared to untreated and miltefosine-treated groups. This chemically modified neolignan induced lethal alterations of the bioenergetic and protein metabolism of Leishmania. Future PKPD and animal efficacy studies are needed to optimize this promising natural-derived compound.

Selenium-Modified Chitosan Induces HepG2 Cell Apoptosis and Differential Protein Analysis

INTRODUCTION

Chitosan is the product of the natural polysaccharide chitin removing part of the acetyl group, and exhibits various physiological and bioactive functions. Selenium modification has been proved to further enhance the chitosan bioactivities, and has been a hot topic recently.

METHODS

The present study aimed to investigate the potential inhibitory mechanism of selenium-modified chitosan (SMC) on HepG2 cells through MTT assays, morphological observation, annexin V-FITC/PI double staining, mitochondrial membrane potential determination, cell-cycle detection, Western blotting, and two-dimensional gel electrophoresis (2-DE).

RESULTS

The results indicated that SMC can induce HepG2 cell apoptosis with the cell cycle arrested in the S and G2/M phases and gradual disruption of mitochondrial membrane potential, reduce the expression of Bcl2, and improve the expression of Bax, cytochrome C, cleaved caspase 9, and cleaved caspase 3. Also, 2-DE results showed that tubulin α1 B chain, myosin regulatory light chain 12A, calmodulin, UPF0568 protein chromosome 14 open reading frame 166, and the cytochrome C oxidase subunit 5B of HepG2 cells were downregulated in HepG2 cells after SMC treatment.

DISCUSSION

These data suggested that HepG2 cells induced apoptosis after SMC treatment via blocking the cell cycle in the S and G2/M phases, which might be mediated through the mitochondrial apoptotic pathway. These results could be of benefit to future practical applications of SMC in the food and drug fields.

Exogenously Scavenged and Endogenously Synthesized Heme Are Differentially Utilized by Mycobacterium tuberculosis

Heme is both an essential cofactor and an abundant source of nutritional iron for the human pathogen Mycobacterium tuberculosis. While heme is required for M. tuberculosis survival and virulence, it is also potentially cytotoxic. Since M. tuberculosis can both synthesize and take up heme, the de novo synthesis of heme and its acquisition from the host may need to be coordinated in order to mitigate heme toxicity. However, the mechanisms employed by M. tuberculosis to regulate heme uptake, synthesis, and bioavailability are poorly understood. By integrating ratiometric heme sensors with mycobacterial genetics, cell biology, and biochemistry, we determined that de novo-synthesized heme is more bioavailable than exogenously scavenged heme, and heme availability signals the downregulation of heme biosynthetic enzyme gene expression. Ablation of heme synthesis does not result in the upregulation of known heme import proteins. Moreover, we found that de novo heme synthesis is critical for survival from macrophage assault. Altogether, our data suggest that mycobacteria utilize heme from endogenous and exogenous sources differently and that targeting heme synthesis may be an effective therapeutic strategy to treat mycobacterial infections. IMPORTANCE Mycobacterium tuberculosis infects ~25% of the world's population and causes tuberculosis (TB), the second leading cause of death from infectious disease. Heme is an essential metabolite for M. tuberculosis, and targeting the unique heme biosynthetic pathway of M. tuberculosis could serve as an effective therapeutic strategy. However, since M. tuberculosis can both synthesize and scavenge heme, it was unclear if inhibiting heme synthesis alone could serve as a viable approach to suppress M. tuberculosis growth and virulence. The importance of this work lies in the development and application of genetically encoded fluorescent heme sensors to probe bioavailable heme in M. tuberculosis and the discovery that endogenously synthesized heme is more bioavailable than exogenously scavenged heme. Moreover, it was found that heme synthesis protected M. tuberculosis from macrophage killing, and bioavailable heme in M. tuberculosis is diminished during macrophage infection. Altogether, these findings suggest that targeting M. tuberculosis heme synthesis is an effective approach to combat M. tuberculosis infections.

Potential Applications of an Exopolysaccharide Produced by Bacillus xiamenensis RT6 Isolated from an Acidic Environment

The Bacillus xiamenensis RT6 strain was isolated and identified by morphological, biochemical and molecular tests from an extreme acidic environment, Rio Tinto (Huelva). Optimisation tests for exopolysaccharide (EPS) production in different culture media determined that the best medium was a minimal medium with glucose as the only carbon source. The exopolymer (EPS_t) produced by the strain was isolated and characterised using different techniques (GC-MS, HPLC/MSMS, ATR-FTIR, TGA, DSC). The molecular weight of EPS_t was estimated. The results showed that the average molecular weight of EPS_t was approximately 2.71 × 10⁴ Da and was made up of a heteropolysaccharide composed of glucose (60%), mannose (20%) and galactose (20%). The EPS_t showed antioxidant capabilities that significantly improved cell viability. Metal chelation determined that EPS_t could reduce the concentration of transition metals such as iron at the highest concentrations tested. Finally, the emulsification study showed that EPS_t was able to emulsify different natural polysaccharide oils, reaching up to an 80% efficiency (olive and sesame oil), and was a good candidate for the substitution of the most polluting emulsifiers. The EPS_t was found to be suitable for pharmaceutical and industrial applications.

N-Benzyl Benzamide Derivatives as Selective Sub-Nanomolar Butyrylcholinesterase Inhibitors for Possible Treatment in Advanced Alzheimer's Disease

Herein, we report a series of selective sub-nanomolar inhibitors against butyrylcholinesterase (BChE). These compounds, bearing a novel N-benzyl benzamide scaffold, inhibited BChE with IC₅₀ from picomolar to nanomolar. The inhibitory activity was confirmed by the surface plasmon resonance assay, showing a sub-nanomolar K_D value, which revealed that the compounds exert the inhibitory effect through directly binding to BChE. Several compounds showed neuroprotective effects verified by the oxidative damage model. Furthermore, the safety of S11-1014 and S11-1033 was demonstrated by the in vivo acute toxicity test. In the behavior study, 0.5 mg/kg S11-1014 or S11-1033 exhibited a marked therapeutic effect, which was almost equal to the treatment with 1 mg/kg rivastigmine, against the cognitive impairment induced by Aβ_1-42. The pharmacokinetics studies characterized the metabolic stability of S11-1014. Thus, N-benzyl benzamide inhibitors are promising compounds with drug-like properties for improving cognitive dysfunction, providing a potential strategy for the treatment of Alzheimer's disease.

Molecular and Supramolecular Approach to Highly Photocytotoxic Phthalocyanines with Dual Cell Uptake Pathways and Albumin-Enhanced Tumor Targeting

Phototherapy for non-invasive cancer treatment has been extensively studied. An urgent challenge in phototherapy application is to fabricate appropriate targeted agents to achieve efficient therapeutic effect. Herein, a molecular and supramolecular approach for targeting phototherapy was reasonably designed and realized through the axial sulfonate modification of silicon(IV) phthalocyanines (Pcs), followed by supramolecular interaction with albumin. This approach can not only improve the photoactivities (e.g., fluorescence emission and reactive oxygen species production) of the Pcs but also enhance their tumor targeting. Most importantly, one of the deigned Pcs (4) can target HepG2 cells through dual cell pathways, leading to an extremely high phototoxicity with an EC₅₀ (i.e., concentration of Pcs to kill 50% of cells under light irradiation) value of 2.0 nM. This finding presents a feasible strategy to realize efficient targeting phototherapy.

Programmed cell death detection methods: a systematic review and a categorical comparison

Programmed cell death is considered a key player in a variety of cellular processes that helps to regulate tissue growth, embryogenesis, cell turnover, immune response, and other biological processes. Among different types of cell death, apoptosis has been studied widely, especially in the field of cancer research to understand and analyse cellular mechanisms, and signaling pathways that control cell cycle arrest. Hallmarks of different types of cell death have been identified by following the patterns and events through microscopy. Identified biomarkers have also supported drug development to induce cell death in cancerous cells. There are various serological and microscopic techniques with advantages and limitations, that are available and are being utilized to detect and study the mechanism of cell death. The complexity of the mechanism and difficulties in distinguishing among different types of programmed cell death make it challenging to carry out the interventions and delay its progression. In this review, mechanisms of different forms of programmed cell death along with their conventional and unconventional methods of detection of have been critically reviewed systematically and categorized on the basis of morphological hallmarks and biomarkers to understand the principle, mechanism, application, advantages and disadvantages of each method. Furthermore, a very comprehensive comparative analysis has been drawn to highlight the most efficient and effective methods of detection of programmed cell death, helping researchers to make a reliable and prudent selection among the available methods of cell death assay. Conclusively, how programmed cell death detection methods can be improved and can provide information about distinctive stages of cell death detection have been discussed.

Genotoxic effects of the ochratoxin A (OTA), its main metabolite (OTα) per se and in combination with fumonisin B1 in HepG2 cells and human lymphocytes

Ochratoxin A (OTA) and fumonisin B₁ (FB₁) are mycotoxins distributed in a wide variety of foods for human or animal consumption and are classified as possible carcinogens for humans. This study aimed to evaluate the cytotoxic, cytostatic and genotoxic effects of OTA and its main metabolite, ochratoxin α (OTα), FB₁ and three combinations of OTA and FB₁ at moderate and environmental doses. Cell viability was evaluated through MTT assay and the trypan blue exclusion method. The cytostatic and genotoxic effects were evaluated through the cytokinesis-block micronucleus assay. The results showed synergistic time- and concentration-dependent cytotoxic effects of one of the combinations of OTA and FB₁. In contrast, significant differences were observed in the micronuclei (MN) frequency from OTA, OTα and coexposure of OTA + FB₁. Some of these combinations increased the frequency of nuclear buds, nucleoplasmic bridges, donut-shaped nuclei, necrotic and apoptotic cells and MN in mononucleated cells. In conclusion, OTA and its main metabolite OTα, as well as the co-exposure of OTA and FB₁, cause stable DNA damage at environmentally relevant concentrations, which was greater in metabolically competent cells. More studies are needed to understand the chemical interactions that occur due to the joint presence of mycotoxins, which occurs commonly.

EBAG9 controls CD8+ T cell memory formation responding to tumor challenge in mice

Insight into processes that determine CD8⁺ T cell memory formation has been obtained from infection models. These models are biased toward an inflammatory milieu and often use high-avidity CD8⁺ T cells in adoptive-transfer procedures. It is unclear whether these conditions mimic the differentiation processes of an endogenous repertoire that proceed upon noninflammatory conditions prevailing in premalignant tumor lesions. We examined the role of cytolytic capacity on CD8⁺ T cell fate decisions when primed by tumor cells or by minor histocompatibility antigen–mismatched leukocytes. CD8⁺ memory commitment was analyzed in Ebag9-deficient mice that exhibited enhanced tumor cell lysis. This property endowed Ebag9^–/– mice with extended control of Tcl-1 oncogene–induced chronic lymphocytic leukemia progression. In Ebag9^–/– mice, an expanded memory population was obtained for anti-HY and anti–SV-40 T antigen–specific T cells, despite unchanged effector frequencies in the primary response. By comparing the single-cell transcriptomes of CD8⁺ T cells responding to tumor cell vaccination, we found differential distribution of subpopulations between Ebag9^+/+ and Ebag9^–/– T cells. In Ebag9^–/– cells, these larger clusters contained genes encoding transcription factors regulating memory cell differentiation and anti-apoptotic gene functions. Our findings link EBAG9-controlled cytolytic activity and the commitment to the CD8⁺ memory lineage.

ANTITUMOR EFFECTS OF TURMERIC ON OVCAR-3 OVARIAN CANCER CELL LİNES

INTRODUCTION

Ovarian cancer is the deadliest gynecological malignancy, usually not detected until the late stages. In vitro cell culture is a method used to study the behavior of cells in a controlled environment. Turmeric has attracted the attention of scientists due to its anticancer potential.

MATERIAL-METHOD

OVCAR-3 cells were cultured in RPMI medium with 100 units/mL-100 μg/mL of penicillin-streptomycin and 10% foetal bovine serum in a CO2 incubator. Turmeric extract was diluted in DMSO. Different concentrations of turmeric extract were prepared. Annexin-V staining was performed to test the translocation of phosphatidylserine to the outer side of the cell membrane as a clear indicator of apoptosis.

RESULTS

Turmeric extract significantly reduced the viability of OVCAR-3 cells both in 24 and 48 hours of exposure. OVCAR-3 cells treated with IC50 concentration of turmeric extract for 24 hours. 82.60% of cells were viable. The percentages of dead, early apoptotic and late apoptotic cells were detected to be 0.80%, 9.70% and 6.90%, respectively. Untreated OVCAR-3 cells have migration ability. OVCAR-3 cells exposed to an IC50 concentration of turmeric extract for 24 hours did not close the scratch area.

CONCLUSION

In this research anticancer effects of turmeric have been demonstrated by different analysis methods.</p>.

Effect of extracts from eggs of Helix aspersa maxima and Helix aspersa aspersa snails on Caco-2 colon cancer cells

Background

Colorectal cancer is the third most commonly diagnosed cancer. Natural compounds, administered together with conventional chemotherapeutic agent(s) and/or radiotherapy, may be a novel element in the combination therapy of this cancer. Considering the anticancer properties of compounds derived from different tissues of various snail species confirmed earlier, the purpose of the present research was to evaluate the effect of extracts from eggs of Helix aspera maxima and Helix aspersa aspersa snails, and fractions of extracts containing particles of different molecular weights on Caco-2 human epithelial colorectal adenocarcinoma cells.

Methods

The extracts and fractions were analyzed for antioxidant activity, phenols and total carbohydrates using colorimetric methods. Lipid peroxidation products and glutathione in eggs were also examined using these methods. Crude protein and fat in eggs were determined. Molecular weights of egg proteins and glycoproteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Astaxanthin, selected vitamins and amino acids in eggs were measured using liquid chromatography methods, and minerals by emission spectroscopy, mass spectrometry or X-ray fluorescence. The action of extracts on the cell viability was determined by the MTT (methylthiazolyldiphenyl-tetrazolium bromide) test, based on the mitochondrial oxidative activity, after 24 and 72 h of treatment. The influence of fractions on the cell viability was assayed after 24 h. The effect of extracts on the percentage of live and dead cells was evaluated by the trypan blue assay, in which live cells exclude trypan blue, while dead cells take up this dye, after 12, 24, 48 and 72 h of treatment. Their influence on the integrity of cell membranes was determined based on the activity of LDH (lactate dehydrogenase), released from damaged cells, after 24 and 72 h of treatment. Then, the effect of extracts on the content of lipid peroxidation products in cells was examined using colorimetric method, after 24 h of treatment. Their influence on types of cell death was determined by flow cytometry, after this time.

Results

The extracts and their fractions containing molecules <3 kDa decreased the cell viability, after 24 h of treatment. The extracts reduced the percentage of live cells (also after 48 h), increased the degree of cell membrane damage and the amount of lipid peroxidation products, induced apoptosis and reduced necrosis.

Conclusions

Antioxidants, phenols, lipid peroxidation products, anticancer peptides, restriction of methionine, appropriate ratio of essential amino acids to non-essential amino acids, vitamin D₃, Ca, Mg, S, Cu, Mn, Zn, Se and other bioactive compounds comprised in the extracts and their additive and synergistic effects may have influenced Caco-2 cells. Natural extracts or the chemical compounds contained in them might be used in the combination therapy of colorectal cancer, which requires further research.

Antileishmanial Effects of Acetylene Acetogenins from Seeds of Porcelia macrocarpa (Warm.) R.E. Fries (Annonaceae) and Semisynthetic Derivatives

As part of our continuous studies involving the prospection of natural products from Brazilian flora aiming at the discovery of prototypes for the development of new antiparasitic drugs, the present study describes the isolation of two natural acetylene acetogenins, (2S,3R,4R)-3-hydroxy-4-methyl-2-(n-eicos-11′-yn-19′-enyl)butanolide (1) and (2S,3R,4R)-3-hydroxy-4-methyl-2-(n-eicos-11′-ynyl)butanolide (2), from the seeds of Porcelia macrocarpa (Warm.) R.E. Fries (Annonaceae). Using an ex-vivo assay, compound 1 showed an IC₅₀ value of 29.9 μM against the intracellular amastigote forms of Leishmania (L.) infantum, whereas compound 2 was inactive. These results suggested that the terminal double bond plays an important role in the activity. This effect was also observed for the semisynthetic acetylated (1a and 2a) and eliminated (1b and 2b) derivatives, since only compounds containing a double bond at C-19 displayed activity, resulting in IC₅₀ values of 43.3 μM (1a) and 23.1 μM (1b). In order to evaluate the effect of the triple bond in the antileishmanial potential, the mixture of compounds 1 + 2 was subjected to catalytic hydrogenation to afford a compound 3 containing a saturated side chain. The antiparasitic assays performed with compound 3, acetylated (3a), and eliminated (3b) derivatives confirmed the lack of activity. Furthermore, an in-silico study using the SwissADME online platform was performed to bioactive compounds 1, 1a, and 1b in order to investigate their physicochemical parameters, pharmacokinetics, and drug-likeness. Despite the reduced effect against amastigote forms of the parasite to the purified compounds, different mixtures of compounds 1 + 2, 1a + 2a, and 1b + 2b were prepared and exhibited IC₅₀ values ranging from 7.9 to 38.4 μM, with no toxicity for NCTC mammalian cells (CC₅₀ > 200 μM). Selectivity indexes to these mixtures ranged from >5.2 to >25.3. The obtained results indicate that seeds of Porcelia macrocarpa are a promising source of interesting prototypes for further modifications aiming at the discovery of new antileishmanial drugs.

Optimization of physicochemical properties is a strategy to improve drug-likeness associated with activity: novel active and selective compounds against Trypanosoma cruzi

Trypanosoma cruzi is the causing agent of Chagas disease, a parasitic infection without efficient treatment for chronic patients. Despite the efforts, no new drugs have been approved for this disease in the last 60 years. Molecular modifications based on a natural product led to the development of a series of compounds (LINS03 series) with promising antitrypanosomal activity, however previous chemometric analysis revealed a significant impact of excessive lipophilicity and low aqueous solubility on potency of amine and amide derivatives. Therefore, this work reports different modifications in the core structure to achieve adequate balance of the physicochemical properties along with biological activity. A set of 34 analogues were designed considering predicted properties related to lipophilicity/hydrosolubility and synthesized to assess their activity and selective toxicity towards the parasite. Results showed that this strategy contributed to improve the drug-likeness of the series while considerable impacts on potency were observed. The rational analysis of the obtained data led to the identification of seven active piperazine amides (28-34, IC₅₀ 8.7 to 35.3 µM against intracellular amastigotes), devoid of significant cytotoxicity to mammalian cells. The addition of water-solubilizing groups and privileged substructures such as piperazines improved the physicochemical properties and overall drug-likeness of these compounds, increased potency and maintained selectivity towards the parasite. The obtained results brought important structure-activity relationship (SAR) data and new lead structures for further modifications were identified to achieve improved antitrypanosoma compounds.

Glutathione-degradable polydopamine nanoparticles as a versatile platform for fabrication of advanced photosensitisers for anticancer therapy

A series of glutathione (GSH)-responsive polydopamine (PDA) nanoparticles (NPs) were prepared using a disulfide-linked dopamine dimer as starting material, of which the size could be tuned systematically by adjusting the amount of ammonia solution used. Molecules of a phthalocyanine (Pc)-based photosensitiser and an epidermal growth factor receptor (EGFR)-targeting peptide were then sequentially immobilised on the surface of the NPs through coupling with the surface functionalities of PDA. The immobilised Pc molecules in the resulting nanosystem were photodynamically inactive due to the strong self-quenching effect and the quenching by the PDA core. Upon exposure to GSH in phosphate-buffered saline or EGFR-positive cancer cells, namely A549 and A431 cells, the NPs were disassembled through cleavage of the disulfide linkages to release the Pc molecules, thereby restoring their fluorescence emission and singlet oxygen generation. The NPs with the smallest size (ca. 200 nm in diameter) exhibited the highest cellular uptake and high photocytotoxicity with IC₅₀ values as low as 0.05 μM based on Pc. These NPs could also accumulate and be activated in the tumour of A431 tumour-bearing nude mice, lighting up the tumour with fluorescence over a period of 72 h and completely eradicating the tumour through laser irradiation for 10 min (675 nm, 20 J cm^-2). The results suggest that these biodegradable and versatile PDA-based NPs can serve as a promising nanoplatform for fabrication of advanced photosensitisers for targeted photodynamic therapy.

Challenges and Tools for In Vitro Leishmania Exploratory Screening in the Drug Development Process: An Updated Review

Leishmaniases are a group of vector-borne diseases caused by infection with the protozoan parasites Leishmania spp. Some of them, such as Mediterranean visceral leishmaniasis, are zoonotic diseases transmitted from vertebrate to vertebrate by a hematophagous insect, the sand fly. As there is an endemic in more than 90 countries worldwide, this complex and major health problem has different clinical forms depending on the parasite species involved, with the visceral form being the most worrying since it is fatal when left untreated. Nevertheless, currently available antileishmanial therapies are significantly limited (low efficacy, toxicity, adverse side effects, drug-resistance, length of treatment, and cost), so there is an urgent need to discover new compounds with antileishmanial activity, which are ideally inexpensive and orally administrable with few side effects and a novel mechanism of action. Therefore, various powerful approaches were recently applied in many interesting antileishmanial drug development programs. The objective of this review is to focus on the very first step in developing a potential drug and to identify the exploratory methods currently used to screen in vitro hit compounds and the challenges involved, particularly in terms of harmonizing the results of work carried out by different research teams. This review also aims to identify innovative screening tools and methods for more extensive use in the drug development process.

Structure-activity relationship, in vitro and in vivo evaluation of novel dienyl sulphonyl fluorides as selective BuChE inhibitors for the treatment of Alzheimer's disease

To discover novel scaffolds as leads against dementia, a series of δ-aryl-1,3-dienesulfonyl fluorides with α-halo, α-aryl and α-alkynyl were assayed for ChE inhibitory activity, in which compound A10 was identified as a selective BuChE inhibitor (IC50 = 0.021 μM for eqBChE, 3.62 μM for hBuChE). SAR of BuChE inhibition showed: (i) o- > m- > p-; -OCH3 > -CH3 > -Cl (-Br) for δ-aryl; (ii) α-Br > α-Cl, α-I. Compound A10 exhibited neuroprotective, BBB penetration, mixed competitive inhibitory effect on BuChE (Ki = 29 nM), and benign neural and hepatic safety. Treatment with A10 could almost entirely recover the Aβ1-42-induced cognitive dysfunction to the normal level, and the assessment of total amount of Aβ1-42 confirmed its anti-amyloidogenic profile. Therefore, the potential BuChE inhibitor A10 is a promising effective lead for the treatment of AD.

(-)-T-Cadinol-a Sesquiterpene Isolated From Casearia sylvestris (Salicaceae)-Displayed In Vitro Activity and Causes Hyperpolarization of the Membrane Potential of Trypanosoma cruzi

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects 6-8 million people worldwide, mainly from developing countries. The treatment is limited to two approved nitro-derivatives, nifurtimox and benznidazole, with several side effects and reduced efficacy. Casearia sylvestris has been used in folk medicine as an antiseptic and cicatrizing in skin diseases. In the present work, the hexane phase from the MeOH extract from the leaves of Casearia sylvestris afforded a fraction composed by the sesquiterpene T-cadinol, which was chemically characterized by NMR and HRMS. The activity of T-cadinol was evaluated against T. cruzi, and IC₅₀ values of 18 (trypomastigotes) and 15 (amastigotes) µM were established. The relation between the mammalian toxicity and the antiparasitic activity resulted in a selectivity index >12. Based on this promising activity, the mechanism of action was investigated by different approaches using fluorescent-based techniques such as plasma membrane permeability, plasma membrane electric potential, mitochondrial membrane electric potential, reactive oxygen species, and the intracellular calcium (Ca²⁺) levels. The obtained results demonstrated that T-cadinol affected neither the parasite plasma membrane nor the electric potential of the membrane. Nevertheless, this compound induced a mitochondrial impairment, resulting in a hyperpolarization of the membrane potential, with decreased levels of reactive oxygen species. No alterations in Ca²⁺ levels were observed, suggesting that T-cadinol may affect the single mitochondria of the parasite. This is the first report about the occurrence of T-cadinol in C. sylvestris, and our data suggest this sesquiterpene as an interesting hit compound for future optimizations in drug discovery studies for Chagas disease.

Kaempferol-3-O-α-(3,4-di-E-p-coumaroyl)-rhamnopyranoside from Nectandra oppositifolia releases Ca2+ from intracellular pools of Trypanosoma cruzi affecting the bioenergetics system

Phytochemical analysis of EtOH extract from leaves of Nectandra oppositifolia afforded three flavonoids: kaempferol (1), kaempferol-3-O-α-rhamnopyranoside (2) and kaempferol-3-O-α-(3,4-di-E-p-coumaroyl)-rhamnopyranoside (3), which were characterized by NMR and ESI-HRMS. When tested against the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, flavonoids 1 and 3 were effective to kill the trypomastigotes with IC₅₀ values of 32.0 and 6.7 μM, respectively, while flavonoid 2 was inactive. Isolated flavonoids 1-3 were also tested in mammalian fibroblasts and showed CC₅₀ values of 24.8, 48.7 and 153.1 μM, respectively. Chemically, these results suggested that the free aglycone plays an important role in the bioactivity while the presence of p-coumaroyl unities linked in the rhamnoside unity is important to enhance the antitrypanosomal activity and reduce the mammalian cytotoxicity. The mechanism of cellular death was investigated for the most potent flavonoid 3 in the trypomastigotes using fluorescent and luminescent-based assays. It indicated that this compound induced neither permeabilization of the plasma membrane nor depolarization of the membrane electric potential. However, early time incubation (20 min) with flavonoid 3 resulted in a constant elevation of the Ca²⁺ levels inside the parasite. This effect was followed by a mitochondrial imbalance, leading to a hyperpolarization and depolarization of the mitochondrial membrane potential, with reduction of the ATP levels. During this time, the levels of reactive oxygen species levels (ROS) were unaltered. The leakage of Ca²⁺ from the intracellular pools can affect the bioenergetics system of T. cruzi, leading to the parasite death. Therefore, flavonoid 3 can be a useful tool for future studies against T. cruzi parasites.

Nutrient Scarcity in a New Defined Medium Reveals Metabolic Resistance to Antibiotics in the Fish Pathogen Piscirickettsia salmonis

Extensive use of antibiotics has been the primary treatment for the Salmonid Rickettsial Septicemia, a salmonid disease caused by the bacterium Piscirickettsia salmonis. Occurrence of antibiotic resistance has been explored in various P. salmonis isolates using different assays; however, P. salmonis is a nutritionally demanding intracellular facultative pathogen; thus, assessing its antibiotic susceptibility with standardized and validated protocols is essential. In this work, we studied the pathogen response to antibiotics using a genomic, a transcriptomic, and a phenotypic approach. A new defined medium (CMMAB) was developed based on a metabolic model of P. salmonis. CMMAB was formulated to increase bacterial growth in nutrient-limited conditions and to be suitable for performing antibiotic susceptibility tests. Antibiotic resistance was evaluated based on a comprehensive search of antibiotic resistance genes (ARGs) from P. salmonis genomes. Minimum inhibitory concentration assays were conducted to test the pathogen susceptibility to antibiotics from drug categories with predicted ARGs. In all tested P. salmonis strains, resistance to erythromycin, ampicillin, penicillin G, streptomycin, spectinomycin, polymyxin B, ceftazidime, and trimethoprim was medium-dependent, showing resistance to higher antibiotic concentrations in the CMMAB medium. The mechanism for antibiotic resistance to ampicillin in the defined medium was further explored and was proven to be associated to a decrease in the bacterial central metabolism, including the TCA cycle, the pentose-phosphate pathway, energy production, and nucleotide metabolism, and it was not associated with decreased growth rate of the bacterium or with the expression of any predicted ARG. Our results suggest that nutrient scarcity plays a role in the bacterial antibiotic resistance, protecting against the detrimental effects of antibiotics, and thus, we propose that P. salmonis exhibits a metabolic resistance to ampicillin when growing in a nutrient-limited medium.

Targeted Delivery and Site-Specific Activation of β-Cyclodextrin-Conjugated Photosensitizers for Photodynamic Therapy through a Supramolecular Bio-orthogonal Approach

Targeted delivery of photosensitizers using hydrophilic and tumor-directing carriers and site-specific activation of their photocytotoxicity are two common strategies to enhance the specificity of anticancer photodynamic therapy. We report herein a novel supramolecular bio-orthogonal approach to integrate these two functions. A β-cyclodextrin-substituted aza-boron-dipyrromethene-based photosensitizer was first complexed with a ferrocene-substituted black-hole quencher to inhibit its photosensitizing ability. Upon encountering the adamantane moieties that had been delivered to target cancer cells through specific binding of the conjugated peptide to the overexpressed epidermal growth factor receptor, the ferrocene-based guest species were displaced due to the stronger binding interactions between β-cyclodextrin and adamantane, thereby restoring the photodynamic activity of the photosensitizer. Hence, this two-step process enabled targeted delivery and site-specific activation of the photosensitizer, as demonstrated through a series of experiments in aqueous media, in a range of cancer cell lines and in tumor-bearing nude mice.

Nanoparticles for Triple Drug Release for Combined Chemo- and Photodynamic Therapy

A pH-responsive drug delivery system (DDS) based on mesoporous silica nanoparticles (MSNs) has been prepared for the delivery of three anticancer drugs with different modes of action. The novelty of this system is its ability to combine synergistic chemotherapy and photodynamic therapy. A photoactive conjugate of a phthalocyanine (Pc) and a topoisomerase I inhibitor (topo-I), namely camptothecin (CPT), linked by a poly(ethylene glycol) (PEG) chain has been synthesized and then loaded into the mesopores of MSNs. Doxorubicin (DOX), which is a topoisomerase II inhibitor (topo-II), has also been covalently anchored to the outer surface of the MSNs through a dihydrazide PEG linker. In the acidic environment of tumor cells, selective release of the three drugs takes place. In vitro studies have demonstrated the endocytosis of the system into HeLa and HepG2 cells, and the subsequent release of the three drugs into the cytoplasm and nucleus. Furthermore, the cytotoxic effect of DOX, CPT and Pc has been assessed in vitro before and upon light irradiation.

Apoptotic Effects of a Thioether Analog of Vitamin K3 in a Human Leukemia Cell Line

Research suggests that thioether analogs of vitamin K₃ (VK₃) can act to preserve the phosphorylation of epidermal growth factor receptors by blocking enzymes (phosphatases) responsible for their dephosphorylation. Additionally, these derivatives can induce apoptosis via mitogen-activated protein kinase and caspase-3 activation, inducing reactive oxygen species (ROS) production, and apoptosis. However, vitamin K₁ exhibits only weak inhibition of phosphatase activity, while the ability of VK₃ to cause oxidative DNA damage has raised concerns about carcinogenicity. Hence, in the current study, we designed, synthesized, and screened a number of VK₃ analogs for their ability to enhance phosphorylation activity, without inducing off-target effects, such as DNA damage. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay revealed that each analog produced a different level of cytotoxicity in the Jurkat human leukemia cell line; however, none elicited a cytotoxic effect that differed significantly from that of the control. Of the VK₃ analogs, CPD5 exhibited the lowest EC₅₀, and flow cytometry results showed that apoptosis was induced at final concentrations of ≥10 μM; hence, only 0.1, 1, and 10 μM were evaluated in subsequent assays. Furthermore, CPD5 did not cause vitamin K-attributed ROS generation and was found to be associated with a significant increase in caspase 3 expression, indicating that, of the synthesized thioether VK₃ analogs, CPD5 was a more potent inducer of apoptosis than VK₃. Hence, further elucidation of the apoptosis-inducing effect of CPD5 may reveal its efficacy in other neoplastic cells and its potential as a medication.

Reactive oxygen species-responsive polydopamine nanoparticles for targeted and synergistic chemo and photodynamic anticancer therapy

A thioketal-linked dimer of 3,4-dihydroxy-L-phenylalanine was prepared which underwent self-polymerisation in the presence of doxorubicin (Dox) in an ethanol/water (1 : 4, v/v) mixture with ammonia. The resulting Dox-encapsulated polydopamine (PDA) nanoparticles were further conjugated with molecules of a zinc(II) phthalocyanine (Pc)-based photosensitiser and a peptide containing the heptapeptide QRHKPRE sequence (labelled as QRH) that can target the epidermal growth factor receptor (EGFR) overexpressed in cancer cells. Upon internalisation into these cells through receptor-mediated endocytosis, these nanoparticles labelled as PDA-Dox-Pc-QRH were disassembled gradually via cleavage of the thioketal linkages by the intrinsic intracellular reactive oxygen species (ROS). The stacked Pc molecules were then disaggregated, resulting in activation of their photosensitising property upon irradiation. The ROS generated by the activated Pc promoted further degradation of the nanoparticles and release of Dox, thereby enhancing cell death by synergistic chemo and photodynamic therapy. Systemic injection of PDA-Dox-Pc-QRH into EGFR-overexpressed tumour-bearing nude mice led to targeted delivery to the tumour, and subsequent light irradiation caused complete tumour ablation without inducing notable toxicity.

Genetic overlap between type 1 diabetes and other autoimmune diseases

Type 1 diabetes (T1D) is a chronic disease caused by the destruction of pancreatic β cells, which is driven by autoreactive T lymphocytes. It has been described that a high proportion of T1D patients develop other autoimmune diseases (AIDs), such as autoimmune thyroid disease, celiac disease, or vitiligo, which suggests the existence of common etiological factors among these disorders. In this regard, genetic studies have identified a high number of loci consistently associated with T1D that also represent established genetic risk factors for other AIDs. In addition, studies focused on identifying the shared genetic component in autoimmunity have described several common susceptibility loci with a potential role in T1D. Elucidation of this genetic overlap has been useful in identifying key molecular pathways with a pathogenic role in multiple disorders. In this review, we summarize recent advances in understanding the shared genetic component between T1D and other AIDs and discuss how the identification of common pathogenic mechanisms can help in the development of new therapeutic approaches as well as in improving the use of existing drugs.

Simplified Derivatives of Dibenzylbutyrolactone Lignans from Hydrocotyle bonariensis as Antitrypanosomal Candidates

The search for the pharmacophore of a bioactive compound, crucial for drug discovery studies, involves the adequate arrangement of different atoms in the molecule. As part of a continuous work aiming discovery of new drug candidates against the protozoan parasite Trypanosoma cruzi, the hexane extract of Hydrocotyle bonariensis was subjected to a bioactivity-guided fractionation to afford two chemically related dibenzylbutyrolactone lignans - hinokinin (1) and hibalactone (2). Compounds 1 and 2 showed activity against trypomastigote with EC₅₀ values of 17.0 and 69.4 μM, respectively. Compound 1 was also active against the clinically relevant form of the parasite, amastigotes, displaying an EC₅₀ value of 34.4 μM. The structure-activity relationship (SAR) indicated that the absence of the double bond at C-7 is a crucial feature for the increment of the antiparasitic activity. The lethal action of the most potent compound 1 was investigated in the trypomastigotes. The fluorescent-based assay with SYTOX Green demonstrated a significant alteration of the plasma membrane permeability of the parasite. Additionally, compound 1 demonstrated no significant hemolytic activity in mice erythrocytes at 200 μM. To search the pharmacophore, three different simplified compounds - 3,4-methylenedioxydihydrocinnamic acid (3), 3,4-methylenedioxydihydrocinnamic alcohol (4) and 3,4-methylenedioxycinnamic acid (5) - were prepared and tested against T. cruzi. These derivatives displayed EC₅₀ values of 37.2 (3), 25.8 (4) and 73.5 (5) μM against trypomastigotes, and 41.3 (3) and 48.2 (4) μM against amastigotes, whereas compound 5 was inactive. Except for compound 2, which resulted in a CC₅₀ value of 114.5 μM, all compounds showed no mammalian cytotoxicity at 200 μM. An in silico ADMET study was performed and predicted values demonstrated an acceptable drug-likeness profile for compounds 1-5. Despite the minor reduction in the potency, the simplified derivatives retained the antitrypanosomal activity against the intracellular amastigotes, even with 95 % reduction of their molecular weight. Additionally, in silico studies suggested them as more soluble compounds, making these simplified structures promising scaffolds for optimization studies in Chagas disease.

Class A scavenger receptor-1/2 facilitates the uptake of bovine milk exosomes in murine bone marrow-derived macrophages and C57BL/6J mice

Bovine milk exosomes (BMEs) are being explored in drug delivery despite their rapid elimination by macrophages. We aimed at identifying the BME transporter in murine bone marrow-derived macrophages (BMDMs). Fluorophore-labeled BMEs were used in transport studies in BMDMs from C57BL/6J and class A scavenger receptor type 1/2 (CASR-1/2) knockout mice and tissue accumulation in macrophage-depleted C57BL/6J mice. Parametric and non-parametric statistics tests for pairwise and multiple comparisons were used. Chemical inhibitors of phagocytosis by cytochalasin D led to a 69 ± 18% decrease in BME uptake compared to controls (P ˂ 0.05), whereas inhibitors of endocytic pathways other than phagocytosis had a modest effect on uptake (P > 0.05). Inhibitors of class A scavenger receptors (CASRs) including CASR-1/2 caused a 70% decrease in BME uptake (P ˂ 0.05). The uptake of BMEs by BMDMs from CASR-1/2 knockout mice was smaller by 58 ± 23% compared to wild-type controls (P ˂ 0.05). Macrophage depletion by clodronate caused a more than 44% decrease in BME uptake in the spleen and lungs (P ˂ 0.05) whereas the decrease observed in liver was not statistically significant. In conclusion, CASR-1/2 facilitates the uptake of BMEs in BMDMs and C57BL/6J mice.

Advanced Nanoparticle-Based Drug Delivery Systems and Their Cellular Evaluation for Non-Small Cell Lung Cancer Treatment

Lung cancers, the number one cancer killer, can be broadly divided into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), with NSCLC being the most commonly diagnosed type. Anticancer agents for NSCLC suffer from various limitations that can be partly overcome by the application of nanomedicines. Nanoparticles is a branch within nanomedicine that can improve the delivery of anticancer drugs, whilst ensuring the stability and sufficient bioavailability following administration. There are many publications available in the literature exploring different types of nanoparticles from different materials. The effectiveness of a treatment option needs to be validated in suitable in vitro and/or in vivo models. This includes the developed nanoparticles, to prove their safety and efficacy. Many researchers have turned towards in vitro models that use normal cells or specific cells from diseased tissues. However, in cellular works, the physiological dynamics that is available in the body could not be mimicked entirely, and hence, there is still possible development of false positive or false negative results from the in vitro models. This article provides an overview of NSCLC, the different nanoparticles available to date, and in vitro evaluation of the nanoparticles. Different types of cells suitable for in vitro study and the important precautions to limit the development of false results are also extensively discussed.

Encapsulating an acid-activatable phthalocyanine-doxorubicin conjugate and the hypoxia-sensitive tirapazamine in polymeric micelles for multimodal cancer therapy

A zinc(ii) phthalocyanine (ZnPc) was conjugated to doxorubicin (Dox) via an acid-labile hydrazone linker. The resulting ZnPc-Dox conjugate was then encapsulated into polymeric micelles formed through self-assembly of a block copolymer of poly(ethylene glycol) and poly(d,l-lactide) both in the absence and presence of the hypoxia-activated prodrug tirapazamine (TPZ) to give ZnPc-Dox@micelles and ZnPc-Dox/TPZ@micelles respectively. These polymeric micelles exhibited an excellent stability in aqueous media, but underwent disassembly in an acidic environment. Upon internalisation into HT29 human colorectal carcinoma cells, fluorescence due to ZnPc and Dox could be observed in the cytoplasm and nucleus respectively for both nanosystems. This observation suggested the disassembly of the polymeric micelles and the cleavage of the hydrazone linker in ZnPc-Dox in the acidic intracellular compartments. These micelles were slightly cytotoxic against HT29 cells in the dark due to the chemotherapeutic effect of Dox and/or TPZ. Upon light irradiation, ZnPc-Dox@micelles showed higher cytotoxicity. The IC50 value under a normoxic condition (0.35 μM based on ZnPc-Dox) was significantly lower than that under hypoxia (>1 μM). With an additional therapeutic component, ZnPc-Dox/TPZ@micelles exhibited higher photocytotoxicity with IC50 values of 0.20 μM and 0.78 μM under normoxia and hypoxia respectively. It is believed that the photodynamic action of this nanosystem consumed the intracellular oxygen and hence triggered the hypoxia-mediated chemotherapeutic action of TPZ. The multimodal antitumor effects of these polymeric micelles were also validated on HT29 tumour-bearing nude mice.

Chemical Constituents from Aerial Parts of Baccharis sphenophylla and Effects against Intracellular Forms of Trypanosoma cruzi

The hexane extract from aerial parts Baccharis sphenophylla Dusén ex Malme (Asteraceae) displayed activity against amastigote forms of Trypanossoma cruzi and was subjected to chromatographic steps to afford one unreported - 7α-hydroxy-ent-abieta-8(14),13(15)-dien-16,12β-olide (1) and three known diterpenes - ent-kaur-16-en-19-oic acid, (2), grandifloric acid (3), and 15β-tiglinoyloxy-ent-kaur-16-en-19-oic acid (4), two sesquiterpenes - spathulenol (5) and oplopanone (6) - as well as hexacosyl p-coumarate (7). Isolated compounds were characterized by NMR and ESI-HR-MS spectra and were evaluated in vitro for activity against amastigote forms of the parasite T. cruzi - the relevant clinical form in the chronic phase of Chagas disease. In addition, the activity of compounds 1-7 against NCTC cells was evaluated. Compounds 1 and 7 showed effectiveness with EC₅₀ values of 21.3 and 16.9 μM, respectively. Both compounds also exhibited reduced toxicity against NCTC cells (CC₅₀ >200 μM) with SI values higher than 9.4 and 11.9. Obtained results suggest that the new ent-abietane diterpene 1 and alkyl coumarate 7 could be used as prototypes for the development of novel and selective semisynthetic derivatives against intracellular forms of T. cruzi.

γ-Lactones from Persea americana and Persea fulva - in Vitro and in Silico Evaluation of Trypanosoma cruzi Activity

In the present study, five known γ-lactones (majoranolide B - 1, majorenolide - 2, majorynolide - 3, lincomolide D - 4, and isolinderanolide E - 5), as well as a new one (perseanolide - 6), were isolated from Persea fulva and P. americana. All isolated compounds exhibited potential activity against trypomastigote forms of Trypanosoma cruzi, whereas compounds 2 (EC₅₀ of 4.8 μM) and 6 (EC₅₀ of 3.6 μM) displayed superior activity than the positive control benznidazole (EC₅₀ of 16.4 μM), with selectivity index (SI) values of 17.8 and >55.6, respectively (benznidazole, SI>12.2). Molecular docking studies were performed for 1-6 against six T. cruzi molecular targets. Using this approach, we observed that, even though perseanolide (6) showed favorable docking to several studied targets, the results were especially promising for hypoxanthine phosphoribosyl transferase (PDB 1TC1). As PDB 1TC1 is associated to the transference of a monophosphorylated ribose from phosphoribosylpyrophosphate (PRPP) in the ribonucleotide synthesis pathway, this interaction may affect the survival of T. cruzi in mammalian cells. The data herein also indicate that possible intermolecular interactions between 6 and PDB 1TC1 derive from (i) hydrogen bonds in the α,β-unsaturated-γ-lactone unity and (ii) hydrophobic interactions in the long-chain alkyl group. Based on our results, perseanolide (6), reported for the first time in this work, can auspiciously contribute to future works regarding new trypanocidal agents.

Discovery of New Hits as Antitrypanosomal Agents by In Silico and In Vitro Assays Using Neolignan-Inspired Natural Products from Nectandra leucantha

In the present study, the phytochemical study of the n-hexane extract from flowers of Nectandra leucantha (Lauraceae) afforded six known neolignans (1–6) as well as one new metabolite (7), which were characterized by analysis of NMR, IR, UV, and ESI-HRMS data. The new compound 7 exhibited potent activity against the clinically relevant intracellular forms of T. cruzi (amastigotes), with an IC₅₀ value of 4.3 μM and no observed mammalian cytotoxicity in fibroblasts (CC₅₀ > 200 μM). Based on the results obtained and our previous antitrypanosomal data of 50 natural and semi-synthetic related neolignans, 2D and 3D molecular modeling techniques were employed to help the design of new neolignan-based compounds with higher activity. The results obtained from the models were important to understand the main structural features related to the biological response of the neolignans and to aid in the design of new neolignan-based compounds with better biological activity. Therefore, the results acquired from phytochemical, biological, and in silico studies showed that the integration of experimental and computational techniques consists of a powerful tool for the discovery of new prototypes for development of new drugs to treat CD.

Antitrypanosomal Lactones from Nectandra barbellata

Twigs of Nectandra barbellata were extracted using a solution of the ionic liquid 1-butyl-3-methylimidazolium bromide (BMImBr) in H₂O, assisted by microwave (MAE). After successive chromatographic steps, one sesquiterpene, costic acid, and three new related lactones, (R)-3(7)-Z-3-hexadec-21-enylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (1), (R)-3(7)-Z-3-hexadecylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (2), and (R)-3(7)-Z-3-docosylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (3), were isolated. After structural elucidation using IR, UV, HRESIMS, NMR, ECD, and VCD, compounds 1-3 were tested against trypomastigote forms of Trypanosoma cruzi. The mechanism of action of bioactive isolated compounds was studied using different fluorescent-based approaches to investigate alterations of the plasma membrane, permeability/electric potential (ΔΨ_p), reactive oxygen species levels, mitochondria (electric membrane potential, ΔΨ_m/ATP levels), Ca²⁺ levels, and pH of the acidocalcisomes. In addition, in silico studies predicted no resemblance to pan assay interference compounds (PAINS).

Novel pyridine-containing sultones: Structure-activity relationship and biological evaluation as selective AChE inhibitors for the treatment of Alzheimer's disease

Novel pyridine-containing sultones were synthesized and evaluated for their cholinesterase (ChE) inhibitory activity. Most of compounds showed selective acetylcholinesterase (AChE) inhibitory activity. The structure-activity relationship (SAR) showed: (i) the fused pyridine-containing sultones increase AChE inhibition, series B>series A; (ii) for series A, the effect of the 4-substituent on AChE activity, p->m- or o-; (iii) for series B, a halophenyl group increase activity. Compound B4 (4-(4-chlorophenyl)-2,2-dioxide-3,4,5,6-tetrahydro-1,2-oxathiino[5,6-h]quinoline) was identified as a selective AChE inhibitor (IC₅₀ =8.93 μM), and molecular docking studies revealed a good fit into TcAChE via hydrogen interactions between the δ-pyridylsultone scaffold with Asp72, Ser122, Phe288, Phe290 and Trp84. Compound B4 showed reversible and non-competitive (K_i =7.67 μM) AChE inhibition, nontoxicity and neuroprotective activity. In vivo studies confirmed that compound B4 could ameliorate the cognitive performance of scopolamine-treated C57BL/6 J mice, suggesting a significant benefit of AChE inhibition for a disease-modifying treatment of AD.

Preparation of glutathione loaded nanoemulsions and testing of hepatoprotective activity on THLE-2 cells

To improve bioavailability and stability of hydrophobic and hydrophilic compounds, nanoemulsions are good alternatives as delivery systems because of their nontoxic and nonirritant nature. Glutathione (GSH) suffers from low stability in water, where its encapsulation in nanoemulsions is a powerful strategy to its stability in aqueous systems. The aim of this study was to obtain nanoemulsions from the hydrophobic/hydrophilic contents of N. sativa seed oil so as to improve GSH stability along with bioavailability of N. sativa seed oil. Then, the prepared nanoemulsions were tested for in vitro hepatoprotective activity against ethanol toxicity. To the best of our knowledge, there is no study on the test of nanoemulsions by the combination of Nigella sativa seed oils and GSH in hepatoprotective activity. Here, nanoemulsions with different contents were prepared using Nigella sativa seed oils. Content analyses and characterisation studies of prepared nanoemulsions were carried out. In order to investigate the protective effects against to ethanol exposure, THLE-2 cells were pretreated with nanoemulsions for 2 h with the maximum benign dose (0.5 mg/mL of nanoemulsions). Ethanol (400 mM) was introduced to pretreated cells and nontreated cells for 48- or 72-h periods, followed by cell viability assay was carried out. Fluorescence microscopy tests revealed the introduction of the nanoemulsions into THLE-2 cells. The findings show that nanoformulations have promising in vitro hepatoprotective effects on the THLE-2 cell line against ethanol exposure.

Culture strategy as a modulator of target assessments: Functionality of suspension versus hanging drop-derived choriocarcinoma spheroids as in vitro model of embryo implantation

The choriocarcinoma spheroid model has been amply applied to study the underlying molecular mechanism of implantation. Reproducibility and functionality of spheroid tumor models were addressed precisely. To mimic embryo-endometrium crosstalk, no functional characteristics of spheroids have been provided based on culture strategies. In this study, choriocarcinoma spheroids were provided as suspension culture (SC) or hanging drop culture (HDC). Primary assessments were performed based on morphology, cellular density, and hormonal secretion. Spheroid-endometrial cross talk was assessed as coculture procedures. Further, alkaline phosphatase (ALP) activity and expression of genes involved in attachment, invasion, and inducing migration were quantified. We found HDC spheroids provided a homogenous-shaped aggregate with a high grade of viability, cellular integration, hormonal secretion, and the dominant role of WNTs expression in their microarchitecture. SC spheroids showed a higher level of ALP activity and the expression of integrated genes in modulating attachment, invasion, and migration abilities. Spheroid confrontation assays clearly clarified the superiority of SC spheroids to crosstalk with epithelial and stromal cells of endometrium in addition to motivating an ideal endometrial response. Conclusively, culture strategies by affecting various molecular signaling pathways should be chosen precisely according to specific target assessments. Specifically, SC assumed as an ideal model in spheroid-endometrial cross talk.

Aporphine Alkaloids from Ocotea puberula with Anti-Trypanosoma Cruzi Potential - Activity of Dicentrine-β-N-Oxide in the Plasma Membrane Electric Potentials

One new aporphine, dicentrine-β-N-oxide (1), together with five related known alkaloids dehydrodicentrine (2), predicentrine (3), N-methyllaurotetanine (4), cassythicine (5), and dicentrine (6) were isolated from the leaves of Ocotea puberula (Lauraceae). Antiprotozoal activity of the isolated compounds was evaluated in vitro against trypomastigote forms of Trypanosoma cruzi. Among the tested compounds, alkaloid 1 exhibited higher potential with EC₅₀ value of 18.2 μM and reduced toxicity against NCTC cells (CC₅₀ >200 μM - SI>11.0), similar to positive control benznidazole (EC₅₀ of 17.7 μM and SI=10.7). Considering the promising results of dicentrine-β-N-oxide (1) against trypomastigotes, the mechanism of parasite death caused by this alkaloid was investigated. As observed, this compound reached the plasma membrane electric potential directly after 2 h of incubation and triggered mitochondrial depolarization, which probably leads to trypomastigote death. Therefore, dicentrine-β-N-oxide (1), reported for the first time in this work, can contribute to future works for the development of new trypanocidal agents.

Metabolite profile of Nectandra oppositifolia Nees & Mart. and assessment of antitrypanosomal activity of bioactive compounds through efficiency analyses

EtOH extracts from the leaves and twigs of Nectandra oppositifolia Nees & Mart. shown activity against amastigote forms of Trypanosoma cruzi. These extracts were subjected to successive liquid-liquid partitioning to afford bioactive CH2Cl2 fractions. UHPLC-TOF-HRMS/MS and molecular networking were used to obtain an overview of the phytochemical composition of these active fractions. Aiming to isolate the active compounds, both CH2Cl2 fractions were subjected to fractionation using medium pressure chromatography combined with semi-preparative HPLC-UV. Using this approach, twelve compounds (1-12) were isolated and identified by NMR and HRMS analysis. Several isolated compounds displayed activity against the amastigote forms of T. cruzi, especially ethyl protocatechuate (7) with EC50 value of 18.1 μM, similar to positive control benznidazole (18.7 μM). Considering the potential of compound 7, protocatechuic acid and its respective methyl (7a), n-propyl (7b), n-butyl (7c), n-pentyl (7d), and n-hexyl (7e) esters were tested. Regarding antitrypanosomal activity, protocatechuic acid and compound 7a were inactive, while 7b-7e exhibited EC50 values from 20.4 to 11.7 μM, without cytotoxicity to mammalian cells. These results suggest that lipophilicity and molecular complexity play an important role in the activity while efficiency analysis indicates that the natural compound 7 is a promising prototype for further modifications to obtain compounds effective against the intracellular forms of T. cruzi.

Facile Synthesis of Cyclic Peptide-Phthalocyanine Conjugates for Epidermal Growth Factor Receptor-Targeted Photodynamic Therapy

A facile procedure for in situ peptide cyclization and phthalocyanine conjugation was developed by utilizing a bifunctional linker incorporated with a bis(bromomethyl)benzene unit and a cyclopentadiene moiety. These functional groups facilitated the nucleophilic substitution with the two cysteine residues of the linear peptides followed by the Diels-Alder reaction with the maleimide moiety attached to a zinc(II) phthalocyanine. With this approach, three cyclic peptide-phthalocyanine conjugates were prepared in 20-26% isolated yield via a one-pot procedure. One of the conjugates containing a cyclic form of the epidermal growth factor receptor (EGFR)-binding peptide sequence CMYIEALDKYAC displayed superior features as an advanced photosensitizer. It showed preferential uptake by two EGFR-positive cancer cell lines (HT29 and HCT116) compared with two EGFR-negative counterparts (HeLa and HEK293), resulting in significantly higher photocytotoxicity. Intravenous administration of this conjugate into HT29 tumor-bearing nude mice resulted in selective localization in tumor and effective inhibition of tumor growth upon photodynamic treatment.

Bioenergetics impairment of Trypanosoma cruzi by the antihypertensive manidipine: A drug repurposing strategy

Considering the lack of effective and safe therapy for the treatment of Chagas disease, the antihypertensive drug manidipine (MDP) was in vitro evaluated against Trypanosoma cruzi. The bioenergetics of trypomastigotes was studied in the presence of the drug using fluorimetric and luminescent assays. Manidipine showed a potent antiparasitic activity, with IC₅₀ values of 0.1 μM (intracellular amastigotes) and 3 μM (trypomastigotes), resulting in a promising selectivity index against the amastigotes (>1459). Using fluorimetric analysis, the drug showed depolarisation of the electric potential of the plasma membrane with no alteration of the permeability. A decrease in ATP levels suggested a bioenergetic alteration of the mitochondria, which was confirmed by the depolarisation of the mitochondrial membrane potential and a slight increase of the ROS levels. This is the first study to show the promising in vitro effectiveness of the antihypertensive MDP against T. cruzi, which may represent a candidate for future investigations in animal models.