Enzyme-responsive vitamin D-based micelles for paclitaxel-controlled delivery and synergistic pancreatic cancer therapy

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most feared diseases worldwide owing to its poor prognosis, negligible therapeutic advances, and high mortality. Herein, multifunctional enzyme-responsive micelles for the controlled delivery of paclitaxel (PTX) were prepared to circumvent its current clinical challenges. Accordingly, two enzyme-responsive structural units composed of Vitamin D3 (VD3) conjugated with polyethylene glycol of different molecular weights (600 Da and 2000 Da) were synthesized and characterized using different analytical methods. By applying the solvent evaporation method, these bioactive structural units self-assembled into sub-100 nm VD3 micelles with minimal batch-to-batch variation, monomodal particle size distribution, and high encapsulation efficiency. The enzyme-triggered disassembly of PTX-loaded VD3 micelles was demonstrated by release studies in the presence of a high esterase content typically featured by PDAC cells. PTX-loaded VD3 micelles also exhibited prominent cell internalization and induced a considerable cytotoxic synergistic effect against human PDAC cells (BxPC-3 cells) in 2D and 3D cell culture models compared with free PTX. The PTX-loaded VD3 micelles were hemocompatible and stable after long-term storage in the presence of biorelevant media, and showed higher efficiency to inhibit the tumor growth compared to the approved clinical nanoformulation (Abraxane®) in an in ovo tumor model. The findings reported here indicate that VD3S-PEG micelles may have a promising role in PDAC therapy, since VD3 could act not only as a hydrophobic core of the micelles but also as a therapeutic agent that provides synergetic therapeutic effects with the encapsulated PTX.

Mussel-Inspired Polydopamine: The Bridge for Targeting Drug Delivery System and Synergistic Cancer Treatment

Polydopamine (PDA), a mussel-inspired molecule, has been recognized as attractive in cancer therapy due to a number of inherent advantages, such as good biocompatibility, outstanding drug-loading capacity, degradability, superior photothermal conversion efficiency, and low tissue toxicity. Furthermore, due to its strong adhesive property, PDA is able to functionalize various nanomaterials, facilitating the construction of a PDA-based multifunctional platform for targeted or synergistic therapy. Herein, recent PDA research, including targeted drug delivery, single-mode therapy, and diverse synergistic therapies against cancer, are summarized and discussed. For synergistic therapy, advanced developments are highlighted, such as photothermal/radiotherapy, chemo-/photothermal/gene therapy, photothermal/immune therapy, and photothermal/photodynamic/immune therapy. Finally, the challenges and promise of PDA for biomedical applications in the future are discussed.

Towards new nanoporous biomaterials: self-assembly of sulfopillar[5]arenes with vitamin D3 into supramolecular polymers

Novel water-soluble, deca-substituted pillar[5]arenes containing thiasulfate and thiacarboxylate fragments were synthesized and characterized. UV-vis, 2D 1H-1H NOESY and DOSY NMR spectroscopy revealed the ability of pillar[5]arenes containing thiasulfate fragments to form an inclusion complex with cholecalciferol (vitamin D3) in a 1 : 2 ratio (lg Kass = 2.2). Using DLS and SEM it was found that upon concentration and/or evaporation of the solvent, the supramolecular polymer (pillar[5]arene/vitamin D3 (1 : 2)) forms a porous material with an average wall diameter of 53 nm. It was shown that the supramolecular polymer is stable during photolysis by UV radiation (k1 = 1.7 × 10-5 s-1).

An online dual-enzyme co-immobilized microreactor based on capillary electrophoresis for enzyme kinetics assays and screening of dual-target inhibitors against thrombin and factor Xa

In this study, an online capillary electrophoresis (CE) based dual-enzyme (thrombin and factor Xa) co-immobilized microreactor (THR-FXa IMER) was constructed for studying enzyme kinetics and screening dual-target inhibitors against THR and FXa with the aid of the polydopamine/graphene oxide (PDA/GO) coating. Based on the developed THR-FXa IMER, the Michaelis-Menten constants (Km) of THR and FXa were calculated to be 187.26 and 48.80 μM, respectively. The inhibition constants (Ki) for two known inhibitors, argatroban and rivaroxaban, on THR and FXa were determined to be 14.73 and 0.41 nM, respectively. In addition, after 30 consecutive runs, the enzymes' activity was remained 98% of the initial immobilized activity for both THR and FXa, which shows that the constructed IMER has good stability and repeatability. Finally, the developed method was successfully applied to screen dual-target inhibitors against THR and FXa from 30 small molecular compounds. Among them, 10 compounds such as salvianolic acid C and epigallocatechin gallate (EGCG) have dual-enzyme inhibitory activity, and 2 compounds named saikosaponin A and oleuropein have single THR inhibitory activity, 5 compounds such as rosemary acid and salvianolic acid B have single FXa inhibitory activity. Finally, the molecular interactions between enzyme and potential inhibitors were further verified via the molecular docking, and a new compound with a theoretically good coagulation inhibition effect was designed by the scaffold hopping study. In summary, the developed THR-FXa IMER is a reliable method for screening THR and/or FXa inhibitors.

Evaluation of Apoptosis and Autophagy Inducing Potential of Berberis aristata, Azadirachta indica, and Their Synergistic Combinations in Parental and Resistant Human Osteosarcoma Cells

Cancer is a multifactorial disease and hence can be effectively overcome by a multi-constituently therapeutic strategy. Medicinal plant extracts represent a perfect example of such stratagem. However, minimal studies have been done till date that portray the effect of extraction techniques on the phyto-constituent profile of plant extracts and its impact on anticancer activity. In the present study, we have evaluated the anticancer potential of methanolic extracts of Berberis aristata root and Azadirachta indica seeds prepared by various extraction techniques in human osteosarcoma (HOS) cells. Soxhlation extract of B. aristata (BAM-SX) and sonication extract of A. indica (AIM-SO) were most effective in inducing apoptosis in parental drug sensitive, as well as resistant cell type developed by repeated drug exposure. Generation of reactive oxygen species and cell cycle arrest preceded caspase-mediated apoptosis in HOS cells. Interestingly, inhibition of autophagy enhanced cell death suggesting the cytoprotective role of autophagy. Combination studies of different methanolic extracts of BAM and AIM were performed, among which, the combination of BAM-SO and AIM-SO (BAAISO) was found to show synergism (IC₅₀ 10.27 µg/ml) followed by combination of BAM-MC and AIM-MC (BAAIMC) with respect to other combinations in the ratio of 1:1. BAAISO also showed synergism when it was added to cisplatin-resistant HOS cells (HCR). Chromatographic profiling of BAM-SX and AIM-SO by high performance thin layer chromatography resulted in identification of berberine (R_f 0.55), palmitine (R_f 0.50) in BAM-SX and azadirachtin A (R_f 0.36), azadirachtin B (R_f 0.56), nimbin (R_f 0.80), and nimbolide (R_f 0.43) in AIM-SO. The cytotoxic sensitivity obtained can be attributed to the above compounds. Our results highlight the importance of extraction technique and subsequent mechanism of action of multi-constituential B. aristata and A. indica against both sensitive and drug refractory HOS cells.

Biosynthesized Protein-Capped Silver Nanoparticles Induce ROS-Dependent Proapoptotic Signals and Prosurvival Autophagy in Cancer Cells

In recent years, the use of silver nanoparticles (AgNPs) in biomedical applications has shown an unprecedented boost along with simultaneous expansion of rapid, high-yielding, and sustainable AgNP synthesis methods that can deliver particles with well-defined characteristics. The present study demonstrates the potential of metal-tolerant soil fungal isolate Penicillium shearii AJP05 for the synthesis of protein-capped AgNPs. The particles were characterized using standard techniques, namely, UV-visible spectroscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The anticancer activity of the biosynthesized AgNPs was analyzed in two different cell types with varied origin, for example, epithelial (hepatoma) and mesenchymal (osteosarcoma). The biological NPs (bAgNPs) with fungal-derived outer protein coat were found to be more cytotoxic than bare bAgNPs or chemically synthesized AgNPs (cAgNPs). Elucidation of the molecular mechanism revealed that bAgNPs induce cytotoxicity through elevation of reactive oxygen species (ROS) levels and induction of apoptosis. Upregulation of autophagy and activation of JNK signaling were found to act as a prosurvival strategy upon bAgNP treatment, whereas ERK signaling served as a prodeath signal. Interestingly, inhibition of autophagy increased the production of ROS, resulting in enhanced cell death. Finally, bAgNPs were also found to sensitize cells with acquired resistance to cisplatin, providing valuable insights into the therapeutic potential of bAgNPs. To the best of our knowledge, this is the first study that provides a holistic idea about the molecular mechanisms behind the cytotoxic activity of protein-capped AgNPs synthesized using a metal-tolerant soil fungus.

Chimeric Nanoparticle: A Platform for Simultaneous Targeting of Phosphatidylinositol-3-Kinase Signaling and Damaging DNA in Cancer Cells

Phosphatidylinositol-3-kinase (PI3K) signaling has been hijacked in different types of cancers. Hence, PI3K inhibitors have emerged as novel targeted therapeutics in cancer treatment as mono and combination therapy along with other DNA damaging drugs. However, targeting PI3K signaling with small molecules leads to the emergence of drug resistance and severe side effects to the cancer patients. To address these, we have developed a biocompatible, biodegradable cholesterol-based chimeric nanoparticle (CNP), which can simultaneously load PI103, doxorubicin, and cisplatin in a controlled ratiometric manner. Size, shape, and morphology of these CNPs were characterized by dynamic light scattering (DLS), field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Increased amounts of PI103, doxorubicin, and cisplatin were released from CNPs through controlled and continuous manner over 120 h at pH = 5.5 compared to neutral pH. The CNPs showed much enhanced in vitro cytotoxicity in HeLa, HL60, MCF7, and MDA-MB-231 cancer cells compared to a free drug cocktail at 24 and 48 h by inducing apoptosis. Confocal laser scanning microscopy (CLSM) imaging revealed that indeed these CNPs were internalized into subcellular lysosomes through endocytosis in a time dependent mode over 6 h and retained inside for 48 h in HeLa, MDA-MB-231, and MCF7 cells. These CNPs showed their efficacy by damaging DNA and inhibiting Akt as a downstream modulator of PI3K signaling in HeLa cervical cancer cells. These CNPs have the potential to open up new directions in next-generation nanomedicine by simultaneous targeting of multiple oncogenic signaling pathways and inducing DNA damage for augmented therapeutic outcome by reducing toxic side effects and overcoming drug resistance.