A colon-targeted podophyllotoxin nanoprodrug: synthesis, characterization, and supramolecular hydrogel formation for the drug combination

Bioconjugation of Podophyllotoxin and Nanosystems: Approaches for Boosting Its Biopharmaceutical and Antitumoral Profile

Podophyllotoxin is a natural compound belonging to the lignan family and is well-known for its great antitumor activity. However, it shows several limitations, such as severe side effects and some pharmacokinetics problems, including low water solubility, which hinders its application as an anticancer agent. Over the past few years, antitumor research has been focused on developing nanotechnology-based medicines or nanomedicines which allow researchers to improve the pharmacokinetic properties of anticancer compounds. Following this trend, podophyllotoxin nanoconjugates have been obtained to overcome its biopharmaceutical drawbacks and to enhance its antitumor properties. The objective of this review is to highlight the advances made over the past few years (2017-2023) regarding the inclusion of podophyllotoxin in different nanosystems. Among the huge variety of nanoconjugates of diverse nature, drug delivery systems bearing podophyllotoxin as cytotoxic payload are organic nanoparticles mainly based on polymer carriers, micelles, and liposomes. Along with the description of their pharmacological properties as antitumorals and the advantages compared to the free drug in terms of biocompatibility, solubility, and selectivity, we also provide insight into the synthetic procedures developed to obtain those podophyllotoxin-nanocarriers. Typical procedures in this regard are self-assembly techniques, nanoprecipitations, or ionic gelation methods among others. This comprehensive perspective aims to enlighten the medicinal chemistry community about the tendencies followed in the design of new podophyllotoxin-based drug delivery systems, their features and applications.

Alginate-Chitosan Biodegradable and Biocompatible Based Hydrogel for Breast Cancer Immunotherapy and Diagnosis: A Comprehensive Review

Breast cancer is the most common type of cancer and the second leading cause of cancer-related mortality in females. There are many side effects due to chemotherapy and traditional surgery, like fatigue, loss of appetite, skin irritation, and drug resistance to cancer cells. Immunotherapy has become a hopeful approach toward cancer treatment, generating long-lasting immune responses in malignant tumor patients. Recently, hydrogel has received more attention toward cancer therapy due to its specific characteristics, such as decreased toxicity, fewer side effects, and better biocompatibility drug delivery to the particular tumor location. Researchers globally reported various investigations on hydrogel research for tumor diagnosis. The hydrogel-based multilayer platform with controlled nanostructure has received more attention for its antitumor effect. Chitosan and alginate play a leading role in the formation of the cross-link in a hydrogel. Also, they help in the stability of the hydrogel. This review discusses the properties, preparation, biocompatibility, and bioavailability of various research and clinical approaches of the multipolymer hydrogel made of alginate and chitosan for breast cancer treatment. With a focus on cases of breast cancer and the recovery rate, there is a need to find out the role of hydrogel in drug delivery for breast cancer treatment.

Facile fabrication of temperature/pH dual sensitive hydrogels based on cellulose and polysuccinimide through aqueous amino-succinimide reaction

A temperature/pH dual sensitive hydrogel with a semi-interpenetrating network (semi-IPN) structure was synthesized through an aqueous amino-succinimide reaction between water-soluble polysuccinimide and polyethyleneimine in the presence of thermosensitive cellulose derivatives. Single-factor experiments were carried out to optimize the preparation conditions of the semi-IPN hydrogel. The swelling behavior and cytotoxicity assay of the hydrogel were tested. Finally, taking 5- fluorouracil (5-Fu) as a model drug, the release performance of the 5-Fu-loaded hydrogel was investigated. The results indicated that the swelling ratio (SR) first decreased and then increased when the pH of the solutions ascended from 2 to 10. The SR decreased with the increase in temperature. In addition, the swelling behavior of the hydrogel was reversible and reproducible under different pH values and temperatures. The prepared hydrogels had good cytocompatibility. The release behavior of 5-Fu was most consistent with the Korsmeyer-Peppas model and followed the case II diffusion. The acidic environment was beneficial for the release of 5-Fu. The preparation process of the semi-IPN hydrogel is simple and the reaction can proceed quickly in water. The strategy introduced here has great potential for application in the preparation of drug carriers.

Chemistry and Biology of Podophyllotoxins: An Update

Podophyllotoxin is an aryltetralin lignan lactone derived from different plants of Podophyllum. It consists of five rings with four chiral centers, one trans-lactone and one aryl tetrahydronaphthalene skeleton with multiple modification sites. Moreover, podophyllotoxin and its derivatives showed lots of bioactivities, including anticancer, anti-inflammatory, antiviral, and insecticidal properties. The demand for podophyllotoxin and its derivatives is rising as a result of their high efficacy. As a continuation of our previous review (Chem. Eur. J., 2017, 23, 4467-4526), herein, total synthesis, biotransformation, structural modifications, bioactivities, and structure-activity relationships of podophyllotoxin and its derivatives from 2017 to 2022 are summarized. Meanwhile, a piece of update information on the origin of new podophyllotoxin analogues from plants from 2014 to 2022 was compiled. We hope that this review will provide a reference for future high value-added applications of podophyllotoxin and its analogues in the pharmaceutical and agricultural fields.

Engineered cyclodextrin-based supramolecular hydrogels for biomedical applications

Cyclodextrin (CD)-based supramolecular hydrogels are polymer network systems with the ability to rapidly form reversible three-dimensional porous structures through multiple cross-linking methods, offering potential applications in drug delivery. Although CD-based supramolecular hydrogels have been increasingly used in a wide range of applications in recent years, a comprehensive description of their structure, mechanical property modulation, drug loading, delivery, and applications in biomedical fields from a cross-linking perspective is lacking. To provide a comprehensive overview of CD-based supramolecular hydrogels, this review systematically describes their design, regulation of mechanical properties, modes of drug loading and release, and their roles in various biomedical fields, particularly oncology, wound dressing, bone repair, and myocardial tissue engineering. Additionally, this review provides a rational discussion on the current challenges and prospects of CD-based supramolecular hydrogels, which can provide ideas for the rapid development of CD-based hydrogels and foster their translation from the laboratory to clinical medicine.

A pH-responsive supramolecular hydrogel encapsulating a CuMnS nanoenzyme catalyst for synergistic photothermal-photodynamic-chemodynamic therapy of tumours

Traditional cancer therapies no longer meet the current demand for cancer precision therapy and personalized treatment and it's essential to develop new therapeutic modalities as well as to investigate new combination anti-tumor mechanisms. Therefore, amphiphilic prodrug polymer chains linking methoxy poly(ethylene glycol) (mPEG) and cinnamaldehyde (CA) with adipic acid dihydrazide (ADH) as the pH-responsive center were designed and synthesized, which could self-assemble into PAC micelles in aqueous solution. A supramolecular hydrogel was formed based on the host-guest interaction between α-cyclodextrin (α-CD) and PAC micelles. Polyetherimide (PEI) modified copper manganese sulfide nanoenzyme catalysts (PCMS NPs) were prepared by a solvothermal method, which could be uniformly dispersed in the hydrogel to form a composite supramolecular hydrogel (PCMS@PAC/α-CD Gel). Under an acidic tumor environment, pH-responsive hydrazone bonds were broken, resulting in the slow release of CA and the amplification of hydrogen peroxide (H2O2) levels. PCMS NPs exerted peroxidase (POD)-like activity and catalase (CAT)-like activity, which could convert H2O2 into hydroxyl radicals (˙OH) and oxygen (O2) to alleviate intra-tumor hypoxia and induce apoptosis, while exerting glutathione oxidase (GPX)-like activity to consume glutathione (GSH) to further enhance the effect of chemodynamic therapy (CDT). Under near-infrared light (NIR) irradiation, PCMS NPs exhibited an excellent photothermal conversion performance, which could rapidly increase the temperature of tumor cells to above 42 °C for photothermal therapy (PTT) and convert O2 to a superoxide anion (˙O2-) by exerting oxidase (OXD)-like activity for photodynamic therapy (PDT). It was demonstrated by in vitro and in vivo experiments that the PCMS@PAC/α-CD Gel was highly cytotoxic to cancer cells and could effectively inhibit tumor growth, indicating the potential for applications in the fields of biomedicine and smart materials.

Research progress of colon-targeted oral hydrogel system based on natural polysaccharides

The quality of life is significantly impacted by colon-related diseases. There have been a lot of interest in the oral colon-specific drug delivery system (OCDDS) as a potential carrier to decrease systemic side effects and protect drugs from degradation in the upper gastrointestinal tract (GIT). Hydrogels are effective oral colon-targeted drug delivery carriers due to their high biodegradability, substantial drug loading, and great biocompatibility. Natural polysaccharides give the hydrogel system unique structure and function to effectively respond to the complex environment of the GIT and deliver drugs to the colon. In this paper, the physiological factors of colonic drug delivery and the pathological characteristics of common colonic diseases are summarized, and the latest advances in the design, preparation and characterization of natural polysaccharide hydrogels are reviewed, which are expected to provide new references for colon-targeted oral hydrogel systems using natural polysaccharides as raw materials.

Recent Advances in Polycaprolactones for Anticancer Drug Delivery

Poly(ε-Caprolactone)s are biodegradable and biocompatible polyesters that have gained considerable attention for drug delivery applications due to their slow degradation and ease of functionalization. One of the significant advantages of polycaprolactone is its ability to attach various functionalities to its backbone, which is commonly accomplished through ring-opening polymerization (ROP) of functionalized caprolactone monomer. In this review, we aim to summarize some of the most recent advances in polycaprolactones and their potential application in drug delivery. We will discuss different types of polycaprolactone-based drug delivery systems and their behavior in response to different stimuli, their ability to target specific locations, morphology, as well as their drug loading and release capabilities.

A Hypoxia-Activated Prodrug Conjugated with a BODIPY-Based Photothermal Agent for Imaging-Guided Chemo-Photothermal Combination Therapy

Hypoxia-activated prodrugs (HAPs) have drawn increasing attention for improving the antitumor effects while minimizing side effects. However, the heterogeneous distribution of the hypoxic region in tumors severely impedes the curative effect of HAPs. Additionally, most HAPs are not amenable to optical imaging, and it is difficult to precisely trace them in tissues. Herein, we carefully designed and synthesized a multifunctional therapeutic BAC prodrug by connecting the chemotherapeutic drug camptothecin (CPT) and the fluorescent photothermal agent boron dipyrromethene (BODIPY) via hypoxia-responsive azobenzene linkers. To enhance the solubility and tumor accumulation, the prepared BAC was further encapsulated into a human serum albumin (HSA)-based drug delivery system to form HSA@BAC nanoparticles. Since the CPT was caged by a BODIPY-based molecule at the active site, the BAC exhibited excellent biosafety. Importantly, the activated CPT could be quickly released from BAC and could perform chemotherapy in hypoxic cancer cells, which was ascribed to the cleavage of the azobenzene linker by overexpressed azoreductase. After irradiation with a 730 nm laser, HSA@BAC can efficiently generate hyperthermia to achieve irreversible cancer cell death by oxygen-independent photothermal therapy. Under fluorescence imaging-guided local irradiation, both in vitro and in vivo studies demonstrated that HSA@BAC exhibited superior antitumor effects with minimal side effects.

Bioinspired Hydroxyapatite Coating Infiltrated with a Graphene Oxide Hybrid Supramolecular Hydrogel Orchestrates Antibacterial and Self-Lubricating Performance

Hydroxyapatite (HA) bioceramic coating has been extensively applied for the modification of metallic implants to improve their biocompatibility and service life after implantation. Unfortunately, HA coating often suffers from high friction, severe wear, and bacterial invasion, which restrict its application in artificial joints. According to a bioinspired soft/hard combination strategy, a novel HA composite coating that is infiltrated with a vancomycin-loaded graphene oxide (GO) hybrid supramolecular hydrogel is developed via vacuum infiltration and a subsequent host-guest interaction-induced self-assembly process. The holes of textured HA ceramic coating act just like a "magic pocket", offering a stable container to form and store GO hybrid hydrogels and even to recycle wear debris as well. The drug-loaded hybrid hydrogels stored in textured HA coating possess a unique shear force and/or frictional heat triggered gel-sol transition and sustained drug release behavior, acting like the extrusion of synovial fluid during articular cartilage movement, leading to a remarkable self-lubrication, anti-wear performance, and promising antibacterial property against Staphylococcus aureus. The friction coefficient and wear rate of composite coating reduced by nearly five times and three orders of magnitude compared with textured HA coating, respectively, which benefited from the synergistic lubricate effect of cyclodextrin-based pseudopolyrotaxane supramolecular hydrogel and GO lubricants.

Azobenzene Based Photo-Responsive Hydrogel: Synthesis, Self-Assembly, and Antimicrobial Activity

A new azobenzene-based symmetric amphiphile was synthesized and characterized using ¹H NMR spectroscopy. Its self-assembly behavior as well as photo-responsive behavior in its solution and gel states were investigated. Such a compound can self-assemble into fiber mesophases in water solvent. After irradiation of the gels with UV light, the trans isomer of the compound rapidly photoisomerized to the cis isomer, which resulted in a rapid destruction of the gel. High temperature also caused a rapid drop in viscosity. To verify the antimicrobial activity of the hydrogel, live and death assays of human fibroblasts L929 properties were used for in vitro cell viability studies. The compound was converted to the terminal tertiary amine in a quaternary ammonium salt molecule by using hydrochloric acid. This azobenzene quaternary ammonium salt has a relatively better antimicrobial effect biocidal activity that was demonstrated when challenged against Escherichia coli on in vitro conditions.

Self-Assembly of Podophyllotoxin-Loaded Lipid Bilayer Nanoparticles for Highly Effective Chemotherapy and Immunotherapy via Downregulation of Programmed Cell Death Ligand 1 Production

Low drug delivery efficiency elevates the cost of medication, lowers the therapeutic efficacy, and appears as a leading reason for unmet needs in anticancer therapies. Herein, we report the development of self-assembled podophyllotoxin-loaded lipid bilayer nanoparticles that inhibit the production of programmed cell death ligand 1 in lung cancer cells and promote tumor-specific immune responses, thus offering a strategy for regulating the immunosuppressive microenvironment of tumors. In addition, encapsulation of podophyllotoxin in the nanoparticles reduced its systemic toxicity, enhanced its penetration into tumors, and increased its antitumor efficacy. Systemic injection of the nanoparticles into tumor-bearing mice not only prevented tumor immune escape but also significantly inhibited tumor growth and extended survival. In general, the podophyllotoxin-loaded nanoparticles exhibited both immunological effects and antitumor effects in addition to having better targeting activity and fewer side effects than free podophyllotoxin. We expect our findings to facilitate the development of therapies for lung cancer.

Novel cytotoxic 1,10-phenanthroline–triterpenoid amphiphiles with supramolecular characteristics capable of coordinating 64Cu(ii) labels

Novel 1,10-phenanthroline–triterpenoid amphiphiles formed nano-assemblies in water, coordinated Cu(ii) and 64Cu(ii) salts for potential cancer monitoring and therapy, and displayed cytotoxicity partly dependent on the formation of nano-assemblies.

Supramolecular hydrogel-infiltrated ceramics composite coating with combined antibacterial and self-lubricating performance

Inspired by the structure and dynamic weeping lubricating mechanism of articular cartilage, a novel composite coating composed of a textured Y₂O₃-stabilized ZrO₂ (YSZ) ceramics reservoir and silver nanoparticles (AgNPs) hybrid supramolecular hydrogel was developed on the basis of a soft/hard combination strategy. The precursor solution including the poly(ethylene glycol) (PEG)-modified AgNPs and α-cyclodextrins (α-CDs) could be infiltrated deep into (50-60 μm) the pores of a textured YSZ ceramics substrate by a vacuum infiltration method, in situ forming a supramolecular hydrogel within the pores through host-guest inclusion between α-CDs and PEG chains distributed onto the surface of AgNPs. The AgNPs hybrid hydrogel showed thixotropic and thermoresponsive gel-sol transition behavior, low cytotoxicity, and excellent drug-loading capacity, as well as significant antibacterial properties. The textured YSZ ceramics not only provided a hard supporting skeleton and stable reservoir to protect the supramolecular hydrogel from destruction under load-bearing or shear condition, but also allowed retaining the stimuli-responsive gel-sol transition property and drug-release capability of the infiltrated hydrogel, endowing the composite coating with excellent antibacterial properties, and self-lubrication and wear-resistance performance. The composite coating in this work brings a new insight into the design of antibacterial and self-lubricating ceramic coatings for artificial joint applications.

Novel Oleanolic Acid-Tryptamine and -Fluorotryptamine Amides: From Adaptogens to Agents Targeting In Vitro Cell Apoptosis

Background: Oleanolic acid is a natural plant adaptogen, and tryptamine is a natural psychoactive drug. To compare their effects of with the effect of their derivatives, tryptamine and fluorotryptamine amides of oleanolic acid were designed and synthesized. Methods: The target amides were investigated for their pharmacological effect, and basic supramolecular self-assembly characteristics. Four human cancer cell lines were involved in the screening tests performed by standard methods. Results: The ability to display cytotoxicity and to cause selective cell apoptosis in human cervical carcinoma and in human malignant melanoma was seen with the three most active compounds of the prepared series of compounds. Tryptamine amide of (3β)-3-(acetyloxy)olean-12-en-28-oic acid (3a) exhibited cytotoxicity in HeLa cancer cell lines (IC₅₀ = 8.7 ± 0.4 µM) and in G-361 cancer cell lines (IC₅₀ = 9.0 ± 0.4 µM). Fluorotryptamine amides of (3β)-3-(acetyloxy)olean-12-en-28-oic acid (compounds 3b and 3c) showed cytotoxicity in the HeLa cancer cell line (IC₅₀ = 6.7 ± 0.4 µM and 12.2 ± 4.7 µM, respectively). The fluorotryptamine amide of oleanolic acid (compound 4c) displayed cytotoxicity in the MCF7 cancer cell line (IC₅₀ = 13.5 ± 3.3 µM). Based on the preliminary UV spectra measured in methanol/water mixtures, the compounds 3a–3c were also found to self-assemble into supramolecular systems. Conclusions: An effect of the fluorine atom present in the molecules on self-assembly was observed with 3b. Enhanced cytotoxicity has been achieved in 3a–4c in comparison with the effect of the parent oleanolic acid (1) and tryptamine. The compounds 3a–3c showed a strong induction of apoptosis in HeLa and G-361 cells after 24 h.

Insight Into the Molecular Mechanism of Podophyllotoxin Derivatives as Anticancer Drugs

Podophyllotoxin (PTOX) is a biologically active compound derived from the podophyllum plant, and both it and its derivatives possess excellent antitumor activity. The PTOX derivatives etoposide (VP-16) and teniposide (VM-26) have been approved by the U.S. Food and Drug Administration (FDA) for cancer treatment, but are far from perfect. Hence, numerous PTOX derivatives have been developed to address the major limitations of PTOX, such as systemic toxicity, drug resistance, and low bioavailability. Regarding their anticancer mechanism, extensive studies have revealed that PTOX derivatives can induce cell cycle G2/M arrest and DNA/RNA breaks by targeting tubulin and topoisomerase II, respectively. However, few studies are dedicated to exploring the interactions between PTOX derivatives and downstream cancer-related signaling pathways, which is reasonably important for gaining insight into the role of PTOX. This review provides a comprehensive analysis of the role of PTOX derivatives in the biological behavior of tumors and potential molecular signaling pathways, aiming to help researchers design and develop better PTOX derivatives.

Triterpenoid-PEG Ribbons Targeting Selectivity in Pharmacological Effects

(1) Background: To compare the effect of selected triterpenoids with their structurally resembling derivatives, designing of the molecular ribbons was targeted to develop compounds with selectivity in their pharmacological effects. (2) Methods: In the synthetic procedures, Huisgen 1,3-dipolar cycloaddition was applied as a key synthetic step for introducing a 1,2,3-triazole ring as a part of a junction unit in the molecular ribbons. (3) Results: The antimicrobial activity, antiviral activity, and cytotoxicity of the prepared compounds were studied. Most of the molecular ribbons showed antimicrobial activity, especially on Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis, with a 50–90% inhibition effect (c = 25 µg·mL⁻¹). No target compound was effective against HSV-1, but 8a displayed activity against HIV-1 (EC₅₀ = 50.6 ± 7.8 µM). Cytotoxicity was tested on several cancer cell lines, and 6d showed cytotoxicity in the malignant melanoma cancer cell line (G-361; IC₅₀ = 20.0 ± 0.6 µM). Physicochemical characteristics of the prepared compounds were investigated, namely a formation of supramolecular gels and a self-assembly potential in general, with positive results achieved with several target compounds. (4) Conclusions: Several compounds of a series of triterpenoid molecular ribbons showed better pharmacological profiles than the parent compounds and displayed certain selectivity in their effects.