The Effect of Cucurbit[7]uril on the Antitumor and Immunomodulating Properties of Oxaliplatin and Carboplatin

Supramolecular nanotherapeutics based on cucurbiturils

Polymeric biomaterials have important applications in aiding clinical disease treatment, including drug delivery, bioimaging, and tissue engineering. Currently, conventional tumor chemotherapy faces obstacles such as poor solubility/stability, inability to target, and uncontrolled drug release in clinical trials, for which the emergence of supramolecular material therapeutics combining non-covalent interactions with conventional therapies is a very promising candidate. Due to their molecular recognition abilities with a range of biomolecules, cucurbit[n]uril (CB[n]), a type of macrocyclic receptors with robust backbones, hydrophobic cavities, and carbonyl-binding channels, have garnered a lot of attention. Therefore, this paper reviews recent advances in CB[n] material-based supramolecular therapeutics for clinical treatments, including targeted delivery applications and related imaging and sensing systems. This study also covers the distinctive benefits of CB materials for biological applications, as well as the trends and prospects of this interdisciplinary subject, based on numerous state-of-the-art research findings.

Platinum-based chemotherapy: trends in organic nanodelivery systems

Despite the investment in platinum drugs research, cisplatin, carboplatin and oxaliplatin are still the only Pt-based compounds used as first line treatments for several cancers, with a few other compounds being approved for administration in some Asian countries. However, due to the severe and worldwide impact of oncological diseases, there is an urge for improved chemotherapeutic approaches. Furthermore, the pharmaceutical application of platinum complexes is hindered by their inherent toxicity and acquired resistance. Nanodelivery systems rose as a key strategy to overcome these challenges, with recognized versatility and ability towards improving the safety, bioavailability and efficacy of the available drugs. Among the known nanocarriers, organic systems have been widely applied, taking advantage of their potential as drug vehicles. Researchers have mainly focused on the development of lipidic and polymeric carriers, including supramolecular structures, with an overall improvement of encapsulated platinum complexes. Herein, an overview of recent trends and strategies is presented, with the main focus on the encapsulation of platinum compounds into organic nanocarriers, showcasing the evolution in the design and development of these promising systems. This comprehensive review highlights formulation methods as well as characterization procedures, providing insights that may be helpful for the development of novel platinum nanocarriers aiming at future pharmaceutical applications.

Evaluation of the Immunosafety of Cucurbit[n]uril In Vivo

Cucurbiturils are a family of macrocyclic oligomers capable of forming host-guest complexes with various molecules. Due to noncovalent binding to drug molecules and low toxicity, cucurbiturils has been extensively investigated as potential carriers for drug delivery. However, the immune system's interactions with different drug carriers, including cucurbiturils, are still under investigation. In this study, we focused on cucurbiturils' immunosafety and immunomodulation properties in vivo. We measured blood counts and lymphocyte subpopulations in blood, spleen, and bone marrow, and assessed the in vivo toxicity to spleen and bone marrow cells after intraperitoneal administration to BALB/c mice. When assessing the effect of cucurbit[6]uril on blood parameters after three intraperitoneal injections within a week in laboratory animals, a decrease in white blood cells was found in mice after injections of cucurbit[6]util, but the observed decrease in the number of white blood cells was within the normal range. At the same time, cucurbit[7]uril and cucurbit[8]uril did not affect the leukocyte counts of mice after three injections. Changes in the number of platelets, erythrocytes, and monocytes, as well as in several other indicators, such as hematocrit or erythrocyte volumetric dispersion, were not detected. We show that cucurbiturils do not have immunotoxicity in vivo, with the exception of a cytotoxic effect on spleen cells after сucurbit[7]uril administration at a high dosage. We also evaluated the effect of cucurbiturils on cellular and humoral immune responses. We founded that cucurbiturils in high concentrations affect the immune system in vivo, and the action of various cucurbiturils differs in different homologues, which is apparently associated with different interactions in the internal environment of the body.

Integrating biocomputational techniques for Breast cancer drug discovery via the HER-2, BCRA, VEGF and ER protein targets

Computational modelling remains an indispensable technique in drug discovery. With myriad of high computing resources, and improved modelling algorithms, there has been a high-speed in the drug development cycle with promising success rate compared to the traditional route. For example, lapatinib; a well-known anticancer drug with clinical applications was discovered with computational drug design techniques. Similarly, molecular modelling has been applied to various disease areas ranging from cancer to neurodegenerative diseases. The techniques ranges from high-throughput virtual screening, molecular mechanics with generalized Born and surface area solvation (MM/GBSA) to molecular dynamics simulation. This review focuses on the application of computational modelling tools in the identification of drug candidates for Breast cancer. First, we begin with a succinct overview of molecular modelling in the drug discovery process. Next, we take note of special efforts on the developments and applications of combining these techniques with particular emphasis on possible breast cancer therapeutic targets such as estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), vascular endothelial growth factor (VEGF), breast cancer gene 1 (BRCA1), and breast cancer gene 2 (BRCA2). Finally, we discussed the search for covalent inhibitors against these receptors using computational techniques, advances, pitfalls, possible solutions, and future perspectives.

Modulation of the Fibrillation Kinetics and Morphology of a Therapeutic Peptide by Cucurbit[7]uril

Fibrillation is a challenge commonly encountered in the formulation and development of therapeutic peptides. Cucurbit[7]urils (CB[7]), a group of water soluble macrocycles, have been reported to suppress fibrillation in insulin and human calcitonin through association with Phe and Tyr residues which drive fibril formation. Here, we report the effect of CB[7] on the fibrillation behavior of the HIV fusion inhibitor enfuvirtide (ENF) that contains N-terminal Tyr and C-terminal Phe residues. Thioflavin T fluorescence, CD spectroscopy, and transmission electron microscopy were used to monitor fibrillation behavior. Fibrillation onset showed a strong pH dependency, with pH 6.5 identified as the condition most suitable to monitor the effects of CB[7]. Binding of CB[7] to wild-type ENF was measured by isothermal titration calorimetry and was consistent with a single site (K_a = 2.4 × 10⁵ M^-1). A weaker interaction (K_a = 2.8 × 10³ M^-1) was observed for an ENF mutant with the C-terminal Phe substituted for Ala (ENFm), suggesting that Phe was the specific site for CB[7] recognition. The onset of ENF fibrillation onset was delayed, rather than fully suppressed, in the presence of CB[7]. The ENFm mutant showed a greater delay in fibrillation onset but with no observable effect on fibrillation kinetics in the presence of CB[7]. Interestingly, ENF/CB[7] and ENFm fibrils exhibited comparable morphologies, differing from those observed for ENF alone. The results indicate that CB[7] is capable of modulating fibrillation onset and the resulting ENF fibrils by specifically binding to the C-terminal Phe residue. The work reinforces the potential of CB[7] as an inhibitor of fibrillation and highlights its role in determining fibril morphologies.

Production of reactive oxygen species by neutrophils and macrophages of F1 hybrid mice (C57Bl6xCBA) in response to stimulation with cucurbit(n)urils (n = 6, 7, 8)

   Background. Due to their very small size, nanomaterials, in particular cucurbiturils, have unique physical and chemical properties that find their application in medicine. However, the toxicity of cucurbiturils is not fully understood; in particular, we are interested in the immunological safety of their use. One of the mechanisms of nanotoxicity is the formation of reactive oxygen species (ROS) by macrophages and neutrophils. Hyperproduction of ROS can lead to oxidative stress and further damage to cell DNA with loss of physiological function and development of pathology.   The aim. Evaluation of the effect of cucurbit[n]urils (n = 6, 7, 8) on the production of reactive oxygen species by mice macrophages and neutrophils.   Materials and methods. F1 hybrid mice (CBAxC57Bl/6) aged 2 months (n = 11) were used in the work. Evaluation of superoxide radical production by peritoneal mouse neutrophils and macrophages was carried out by spectrophotometric method for determining the reduction of p-nitroblue tetrazolium (NBT) to formazan.   Results. It was shown that CB[6] and CB[7] at concentrations of 0.5 and 0.3 mM do not have an inhibitory effect on ROS synthesis, but, on the contrary, significantly increase ROS production by macrophages. In addition, CB[6] 0.3 mM increases the level of ROS in neutrophils.   Conclusion. Cucurbiturils can lead to an increase in the production of ROS in immunocompetent cells, depending on the concentration used (0.3 mM and higher).

Effects of artesunate on the malignant biological behaviors of non-small cell lung cancer in human and its mechanism

We aimed to assess the effects of artesunate (ART) on the proliferation, migration, invasion and apoptosis of the non-small cell lung cancer cells A549 and H1299. The effects of ART and carboplatin (CBP) alone or in combination on the viability of A549 and H1299 cells were evaluated by MTT assay. The effects of 30 μg/ml ART on cell invasion, migration and apoptosis were evaluated by Transwell assay, scratch assay and flow cytometry, respectively. The protein expressions of human antigen R (HuR) and MMP-9 after treatment with 30 μg/ml ART for 48 h were detected by Western blotting. After 48 h of treatment, 9 μg/ml ART in combination with 7 μg/ml CBP exerted a mild synergistic effect on cell viability. The migration rates of cells treated with 30 μg/ml ART and number of invasive cells were significantly lower, and the apoptosis rates were higher than those of the DMSO-treated group. HuR and MMP-9 expressions in cells treated with 30 μg/ml ART for 48 h were significantly lower than those of the DMSO-treated group. ART suppresses the proliferation, migration and invasion of A549 and H1299 cells and induces their apoptosis, probably being associated with decreased expressions of HuR and MMP-9 proteins.

Synthesis, Characterization and Host-Guest Complexation of Asplatin: Improved In Vitro Cytotoxicity and Biocompatibility as Compared to Cisplatin

Para-sulfocalix[n]arenes are promising host molecules that can accommodate various chemotherapeutic drugs. Pt(IV)-based complexes, including satraplatin and asplatin, are promising alternatives that overcome the shortcomings of Pt(II) complexes. In this study, asplatin has been synthesized by fusing acetylsalicylic acid (aspirin) and cisplatin. Furthermore, it has been characterized using 1H NMR, mass spectrometry, elemental analysis, and UHPLC. A host-guest complex of asplatin and p-sulfocalix[4]arene (PSC4) has been developed and characterized using UV, Job's plot analysis, HPLC, and density functional theory (DFT) calculations. The experimental and computational investigations propose that a 1:1 complex between asplatin and PSC4 is formed. The stability constant of the designed complex has been determined using Job's plot and UHPLC and computed to be 9.1 × 104 M-1 and 8.7 × 104 M-1, which corresponds to a free energy of complexation of -6.8 kcal mol-1, while the calculated value for the inclusion free energy is -13.2 kcal mol-1. Both experimentally and theoretically estimated complexation free energy show that a stable host-guest complex can be formed in solution. The in vitro drug release study displayed the ability of the complex to release its cargo at a cancerous pH (pH of 5.5). Additionally, the asplatin/PSC4 complex is shown to be biocompatible when tested on human skin fibroblast noncancerous cells, demonstrating the highest in vitro cytotoxic activity against (MCF-7), cervical (HeLa), and lung cancer cells (A-549), with IC50 values of 0.75, 2.15, and 3.60 µg/mL, respectively. This is as compared to either cisplatin (IC50 of 5.47, 5.94 and 9.61 µg/mL, respectively) or asplatin (IC50 of 1.54, 5.05 and 3.91 µg/mL, respectively). On the other hand, the free asplatin exhibited higher cytotoxicity on cancerous cells and lower toxicity on noncancerous cells. The outcomes of the present joint theoretical and experimental investigation reinforce the interest in platinum-based anticancer therapeutics when they are protected from undesired interactions and suggest the use of the PSC4 macromolecule as a promising carrier for Pt(IV) anticancer drugs. The formed asplatin/PSC4 inclusion complex may represent an effective chemotherapeutic agent.

Supramolecular co-encapsulation of a photosensitizer and chemotherapeutic drug in cucurbit[8]uril for potential chemophototherapy

Supramolecular strategies as well as combinatorial approaches have been proposed to improve cancer therapeutics. In this work, we investigated the encapsulation of the photosensitizer acridine orange (AO) and the chemotherapeutic drug oxaliplatin (OxPt) in cucurbit[8]uril (CB[8]), and tested their effect both separate and combined on tumoral cells cultivated in vitro. Binding constants and enthalpies of reaction for the AO@CB[8], (AO)₂@CB[8] and OxPt@CB[8] complexes were determined by isothermal titration calorimetry. In the case of AO, a negative cooperativity for the binding of the second AO molecule was found, in agreement with previous fluorescence titration data. We show herein that the AO@CB[8] complex was effectively incorporated within the cells and showed important phototoxicity, while the OxPt@CB[8] complex was cytotoxic only at long incubation times (24 h). Pre-treatment of the cells with the OxPt@CB[8] complex for 24 h inhibited any photodynamic action by the later treatment with the AO@CB[8] complex. However, when both complexes were co-incubated for 90 min, the combined cytotoxicity/phototoxicity was superior to any of the treatments individually. A cooperative effect was identified that added up to an extra 30% cytotoxicity/phototoxicity. The results point to an interesting system where a photosensitizer and chemotherapeutic drug are co-encapsulated in a macrocycle to develop chemophototherapy applications.