Synergistic antitumor activity of camptothecin-doxorubicin combinations and their conjugates with hyaluronic acid

The Influence of Graphene Oxide-Fe3O4 Differently Conjugated with 10-Hydroxycampthotecin and a Rotating Magnetic Field on Adenocarcinoma Cells

Nanoparticles (e.g., graphene oxide, graphene oxide-Fe3O4 nanocomposite or hexagonal boron nitride) loaded with anti-cancer drugs and targeted at cancerous cells allowed researchers to determine the most effective in vitro conditions for anticancer treatment. For this reason, the main propose of the present study was to determine the effect of graphene oxide (GO) with iron oxide (Fe3O4) nanoparticles (GO-Fe3O4) covalently (c-GO-Fe3O4-HCPT) and non-covalently (nc-GO-Fe3O4-HCPT) conjugated with hydroxycamptothecin (HCPT) in the presence of a rotating magnetic field (RMF) on relative cell viability using the MCF-7 breast cancer cell line. The obtained GO-Fe3O4 nanocomposites demonstrated the uniform coverage of the graphene flakes with the nanospheres, with the thickness of the flakes estimated as ca. 1.2 nm. The XRD pattern of GO-Fe3O4 indicates that the crystal structure of the magnetite remained stable during the functionalization with HCPT that was confirmed with FTIR spectra. After 24 h, approx. 49% and 34% of the anti-cancer drug was released from nc-GO-Fe3O4-HCPT and c-GO-Fe3O4-HCPT, respectively. The stronger bonds in the c-GO-Fe3O4-HCPT resulted in a slower release of a smaller drug amount from the nanocomposite. The combined impact of the novel nanocomposites and a rotating magnetic field on MCF-7 cells was revealed and the efficiency of this novel approach has been confirmed. However, MCF-7 cells were more significantly affected by nc-GO-Fe3O4-HCPT. In the present study, it was found that the concentration of nc-GO-Fe3O4-HCPT and a RMF has the highest statistically significant influence on MCF-7 cell viability. The obtained novel nanocomposites and rotating magnetic field were found to affect the MCF-7 cells in a dose-dependent manner. The presented results may have potential clinical applications, but still, more in-depth analyses need to be performed.

A dual-sensitive nanoparticle-mediated deepening synergistic therapy strategy involving DNA damage and ICD stimuli to treat triple-negative breast cancer

Triple-negative breast cancer (TNBC) is one of the most aggressive cancers with an immunosuppressive microenvironment, and achieving a satisfactory effect from monotherapies, such as chemotherapy, photodynamic therapy (PDT) or immunotherapy, remains difficult. To solve this puzzle, a deepening synergistic therapy strategy of DNA damage and immunogenic cell death (ICD) stimuli was proposed. We engineered a doxorubicin (DOX) and 4-(hydroxymethyl) phenylboronic acid pinacol ester (PBAP) prodrug polymer, and encapsulated chlorin e6 (Ce6) to obtain the hyaluronidase (HAase) and H2O2 dual-sensitive responsive nanoparticles (Ce6/HDP NPs). The NPs displayed efficient intratumoral accumulation and cellular internalization properties due to the active targeting of the hyaluronic acid (HA). The dual DNA damage of the chemotherapy and ROS production directly caused tumor cell apoptosis. The strong ICD stimuli, which were induced by ROS production and GSH depletion, generated an amplified immunogenicity to activate tumor immunotherapy in vivo. In this manner, the NPs could significantly inhibit primary tumor, abscopal tumor, pulmonary metastasis and recurrent tumor in a subcutaneous 4T1 tumor model, with effective biosafety. This study has provided a promising deepening synergistic therapy strategy against TNBC.

Combination of bioaffinity ultrafiltration-UFLC-ESI-Q/TOF-MS/MS, in silico docking and multiple complex networks to explore antitumor mechanism of topoisomerase I inhibitors from Artemisiae Scopariae Herba

BACKGROUND

Artemisiae Scopariae Herba (ASH) has been widely used as plant medicine in East Asia with remarkable antitumor activity. However, the underlying mechanisms have not been fully elucidated.

METHODS

This study aimed to construct a multi-disciplinary approach to screen topoisomerase I (topo I) inhibitors from ASH extract, and explore the antitumor mechanisms. Bioaffinity ultrafiltration-UFLC-ESI-Q/TOF-MS/MS was used to identify chemical constitution of ASH extract as well as the topo I inhibitors, and in silico docking coupled with multiple complex networks was applied to interpret the molecular mechanisms.

RESULTS

Crude ASH extract exhibited toxicogenetic and antiproliferative activities on A549 cells. A series of 34 ingredients were identified from the extract, and 6 compounds were screened as potential topo I inhibitors. Docking results showed that the formation of hydrogen bond and π-π stacking contributed most to their binding with topo I. Interrelationships among the 6 compounds, related targets and pathways were analyzed by multiple complex networks model. These networks displayed power-law degree distribution and small-world property. Statistical analysis indicated that isorhamnetin and quercetin were main active ingredients, and that chemical carcinogenesis-reactive oxygen species was the critical pathway. Electrophoretic results showed a therapeutic effect of ASH extract on the conversion of supercoiled DNA to relaxed forms, as well as potential synergistic effect of isorhamnetin and quercetin.

CONCLUSIONS

The results improved current understanding of Artemisiae Scopariae Herba on the treatment of tumor. Moreover, the combination of multi-disciplinary methods provided a new strategy for the study of bioactive constituents in medicinal plants.

The crosslink between the hyaluronic acid and drugs treated by reactive oxygen species produced in plasma based on the molecular dynamics simulation

Hyaluronic Acid (HA)-based pre-drugs can enable targeted drug delivery to cancer cells with CD44-high expressing, thus, it is essential to design an efficient, target specific drug delivery system based on HA. Plasma, as a simple and clean tool, has been widely used in the modification and crosslinking of biological materials in recent years. In this paper, we used the Reactive Molecular Dynamic (RMD) to explore the reaction between reactive oxygen species (ROS) in plasma and HA with drugs (PTX, SN-38, and DOX), in order to examine possible drug-coupled systems. The simulation results indicated the acetylamino groups in HA could be oxidized to unsaturated acyl groups, which offers the possibility of crosslinking. Three drugs also exposed the unsaturated atoms under the impact of ROS, which can cross-link directly to HA through CO and CN bonds, forming a drug coupling system with better release. This study revealed the exposure of active sites on HA and drugs by ROS impact in plasma, allowing us to study the crosslinking mechanism between HA and drugs at molecular level deeply, and also provided a new light for establishment of HA-based targeted drug delivery system.

Ultrasound-mediated delivery of flexibility-tunable polymer drug conjugates for treating glioblastoma

Effective chemotherapy delivery for glioblastoma multiforme (GBM) is limited by drug transport across the blood-brain barrier and poor efficacy of single agents. Polymer-drug conjugates can be used to deliver drug combinations with a ratiometric dosing. However, the behaviors and effectiveness of this system have never been well investigated in GBM models. Here, we report flexible conjugates of hyaluronic acid (HA) with camptothecin (CPT) and doxorubicin (DOX) delivered into the brain using focused ultrasound (FUS). In vitro toxicity assays reveal that DOX-CPT exhibited synergistic action against GBM in a ratio-dependent manner when delivered as HA conjugates. FUS is employed to improve penetration of DOX-HA-CPT conjugates into the brain in vivo in a murine GBM model. Small-angle x-ray scattering characterizations of the conjugates show that the DOX:CPT ratio affects the polymer chain flexibility. Conjugates with the highest flexibility yield the highest efficacy in treating mouse GBM in vivo. Our results demonstrate the association of FUS-enhanced delivery of combination chemotherapy and the drug-ratio-dependent flexibility of the HA conjugates. Drug ratio in the polymer nanocomplex may thus be employed as a key factor to modulate FUS drug delivery efficiency via controlling the polymer flexibility. Our characterizations also highlight the significance of understanding the flexibility of drug carriers in ultrasound-mediated drug delivery systems.

Recent advances in mesoporous silica nanoparticle-based targeted drug-delivery systems for cancer therapy

Targeted drug-delivery systems are a growing research topic in tumor treatment. In recent years, mesoporous silica nanoparticles (MSNs) have been extensively studied and applied in noninvasive and biocompatible drug-delivery systems for tumor therapy due to their outstanding advantages, which include high surface area, large pore volume, tunable pore size, easy surface modification and stable framework. The advances in the application of MSNs for anticancer drug targeting are covered and highlighted in this review, and the challenges and prospects of MSN-based targeted drug-delivery systems are discussed. This review provides new insights for researchers interested in targeted drug-delivery systems against cancer.

Optimization of the Natural Product Calothrixin A to Discover Novel Dual Topoisomerase I and II Inhibitors with Improved Anticancer Activity

Calothrixin A (CAA) is a dual Topo I and II inhibitor but exhibits poor antiproliferative activities and water solubility. Herein, a library of novel CAA analogues was synthesized. Among them, compound F16 exhibited superior water solubility (>5 mg/mL) as compared to CAA (<5 μg/mL). The mechanism of action studies confirmed that F16 acted as a dual Topo I and II poison. Furthermore, F16 displayed potent antiproliferative activities against high Topo I and II expression cell lines A375 and HCT116, with IC₅₀ values of 20 and 50 nM, respectively. In xenograft models, F16 reduced the tumor growth at a dose of 10 or 20 mg/kg without apparent effect on the mouse weight, while the clinically used Topo II inhibitor VP-16 dramatically reduced the mouse weight. Collectively, our data demonstrated that F16 could be a promising lead for the development of novel dual Topo I and II antitumor agents.

A Novel Hyaluronic Acid-Black Rice Anthocyanins Nanocomposite: Preparation, Characterization, and Its Xanthine Oxidase (XO)-Inhibiting Properties

To promote the normal metabolism of human uric acid, high-performance hyaluronic acid-black rice anthocyanins (HAA) nanocomposite particles were successfully prepared by a simple crosslinking method as a novel xanthine oxidase inhibitor. Its structure and properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), and X-ray diffraction (XRD). SEM and TEM electron microscopy showed an obvious double-layer spherical structure with a particle size of ~298 nm. FT-IR and XRD analysis confirmed that black rice anthocyanins (ATC) had been successfully loaded into the hyaluronic acid (HA) structure. Nanocomposite particles (embedded form) showed higher stability in different environments than free black rice ATC (unembedded form). In addition, the preliminary study showed that the inhibition rate of the nanocomposite particles on Xanthine oxidase (XO) was increased by 40.08%. These results indicate that HAA nanocomposite particles can effectively improve black rice ATC's stability and activity, creating an ideal new material for inhibiting XO activity that has a broad application prospect.

pH-Responsive Polymer Nanomaterials for Tumor Therapy

The complexity of the tumor microenvironment presents significant challenges to cancer therapy, while providing opportunities for targeted drug delivery. Using characteristic signals of the tumor microenvironment, various stimuli-responsive drug delivery systems can be constructed for targeted drug delivery to tumor sites. Among these, the pH is frequently utilized, owing to the pH of the tumor microenvironment being lower than that of blood and healthy tissues. pH-responsive polymer carriers can improve the efficiency of drug delivery in vivo, allow targeted drug delivery, and reduce adverse drug reactions, enabling multifunctional and personalized treatment. pH-responsive polymers have gained increasing interest due to their advantageous properties and potential for applicability in tumor therapy. In this review, recent advances in, and common applications of, pH-responsive polymer nanomaterials for drug delivery in cancer therapy are summarized, with a focus on the different types of pH-responsive polymers. Moreover, the challenges and future applications in this field are prospected.

Hydrogels and Hydrogel Nanocomposites: Enhancing Healthcare through Human and Environmental Treatment

Humans are constantly exposed to exogenous chemicals throughout their life, which can lead to a multitude of negative health impacts. Advanced materials can play a key role in preventing or mitigating these impacts through a wide variety of applications. The tunable properties of hydrogels and hydrogel nanocomposites (e.g., swelling behavior, biocompatibility, stimuli responsiveness, functionality, etc.) have deemed them ideal platforms for removal of environmental contaminants, detoxification, and reduction of body burden from exogenous chemical exposures for prevention of disease initiation, and advanced treatment of chronic diseases, including cancer, diabetes, and cardiovascular disease. In this review, three main junctures where the use of hydrogel and hydrogel nanocomposite materials can intervene to positively impact human health are highlighted: 1) preventing exposures to environmental contaminants, 2) prophylactic treatments to prevent chronic disease initiation, and 3) treating chronic diseases after they have developed.

Hyaluronic Acid Nanoparticles for Immunogenic Chemotherapy of Leukemia and T-Cell Lymphoma

Ratiometric delivery of combination chemotherapy can achieve therapeutic efficacy based on synergistic interactions between drugs. It is critical to design such combinations with drugs that complement each other and reduce cancer growth through multiple mechanisms. Using hyaluronic acid (HA) as a carrier, two chemotherapeutic agents-doxorubicin (DOX) and camptothecin (CPT)-were incorporated and tested for their synergistic potency against a broad panel of blood-cancer cell lines. The pair also demonstrated the ability to achieve immunogenic cell death by increasing the surface exposure levels of Calreticulin, thereby highlighting its ability to induce apoptosis via an alternate pathway. Global proteomic profiling of cancer cells treated with HA-DOX-CPT identified pathways that could potentially predict patient sensitivity to HA-DOX-CPT. This lays the foundation for further exploration of integrating drug delivery and proteomics in personalized immunogenic chemotherapy.

Re-engineering the inner surface of ferritin nanocage enables dual drug payloads for synergistic tumor therapy

Rationale: With the advantages of tumor-targeting, pH-responsive drug releasing, and biocompatibility, ferritin nanocage emerges as a promising drug carrier. However, its wide applications were significantly hindered by the low loading efficiency of hydrophobic drugs. Herein, we redesigned the inner surface of ferritin drug carrier (ins-FDC) by fusing the C- terminus of human H ferritin (HFn) subunit with optimized hydrophobic peptides. Methods: Hydrophobic and hydrophilic drugs were encapsulated into the ins-FDC through the urea-dependent disassembly/reassembly strategy and the natural drug entry channel of the protein nanocage. The morphology and drug loading/releasing abilities of the drug-loaded nanocarrier were then examined. Its tumor targeting character, system toxicity, application in synergistic therapy, and anti-tumor action were further investigated. Results: After optimization, 39 hydrophobic Camptothecin and 150 hydrophilic Epirubicin were encapsulated onto one ins-FDC nanocage. The ins-FDC nanocage exhibited programed drug release pattern and increased the stability and biocompatibility of the loaded drugs. Furthermore, the ins-FDC possesses tumor targeting property due to the intrinsic CD71-binding ability of HFn. The loaded drugs may penetrate the brain blood barrier and accumulate in tumors in vivo more efficiently. As a result, the drugs loaded on ins-FDC showed reduced side effects and significantly enhanced efficacy against glioma, metastatic liver cancer, and chemo-resistant breast tumors. Conclusions: The ins-FDC nanocarrier offers a promising novel means for the delivery of hydrophobic compounds in cancer treatments, especially for the combination therapies that use both hydrophobic and hydrophilic chemotherapeutics.

Gold Nanoclusters: Imaging, Therapy, and Theranostic Roles in Biomedical Applications

For the past two decades, atomic gold nanoclusters (AuNCs, ultrasmall clusters of several to 100 gold atoms, having a total diameter of <2 nm) have emerged as promising agents in the diagnosis and treatment of cancer. Owing to their small size, significant quantization occurs to their conduction band, which leads to emergent photonic properties and the disappearance of the plasmonic responses observed in larger gold nanoparticles. For example, AuNCs exhibit native luminescent properties, which have been well-explored in the literature. Using proteins, peptides, or other biomolecules as structural scaffolds or capping ligands, required for the stabilization of AuNCs, improves their biocompatibility, while retaining their distinct optical properties. This paved the way for the use of AuNCs in fluorescent bioimaging, which later developed into multimodal imaging combined with computer tomography and magnetic resonance imaging as examples. The development of AuNC-based systems for diagnostic applications in cancer treatment was then made possible by employing active or passive tumor targeting strategies. Finally, the potential therapeutic applications of AuNCs are extensive, having been used as light-activated and radiotherapy agents, as well as nanocarriers for chemotherapeutic drugs, which can be bound to the capping ligand or directly to the AuNCs via different mechanisms. In this review, we present an overview of the diverse biomedical applications of AuNCs in terms of cancer imaging, therapy, and combinations thereof, as well as highlighting some additional applications relevant to biomedical research.

Design of Bio-Responsive Hyaluronic Acid-Doxorubicin Conjugates for the Local Treatment of Glioblastoma

Glioblastoma is an unmet clinical need. Local treatment strategies offer advantages, such as the possibility to bypass the blood–brain barrier, achieving high drug concentrations at the glioblastoma site, and consequently reducing systemic toxicity. In this study, we evaluated the feasibility of using hyaluronic acid (HA) for the local treatment of glioblastoma. HA was conjugated to doxorubicin (DOX) with distinct bio-responsive linkers (direct amide conjugation HA-NH-DOX), direct hydrazone conjugation (HA-Hz-DOX), and adipic hydrazone (HA-AdpHz-DOX). All HA-DOX conjugates displayed a small size (less than 30 nm), suitable for brain diffusion. HA-Hz-DOX showed the best performance in killing GBM cells in both 2D and 3D in vitro models and displayed superior activity in a subcutaneous GL261 tumor model in vivo compared to free DOX and other HA-DOX conjugates. Altogether, these results demonstrate the feasibility of HA as a polymeric platform for the local treatment of glioblastoma and the importance of rationally designing conjugates.

Newly developed dual topoisomerase inhibitor P8-D6 is highly active in ovarian cancer

Background:

Ovarian cancer (OvCa) constitutes a rare and highly aggressive malignancy and is one of the most lethal of all gynaecologic neoplasms. Due to chemotherapy resistance and treatment limitations because of side effects, OvCa is still not sufficiently treatable. Hence, new drugs for OvCa therapy such as P8-D6 with promising antitumour properties have a high clinical need. The benzo[c]phenanthridine P8-D6 is an effective inductor of apoptosis by acting as a dual topoisomerase I/II inhibitor.

Methods:

In the present study, the effectiveness of P8-D6 on OvCa was investigated in vitro. In various OvCa cell lines and ex vivo primary cells, the apoptosis induction compared with standard therapeutic agents was determined in two-dimensional monolayers. Expanded by three-dimensional and co-culture, the P8-D6 treated cells were examined for changes in cytotoxicity, apoptosis rate and membrane integrity via scanning electron microscopy (SEM). Likewise, the effects of P8-D6 on non-cancer human ovarian surface epithelial cells and primary human hepatocytes were determined.

Results:

This study shows a significant P8-D6-induced increase in apoptosis and cytotoxicity in OvCa cells which surpasses the efficacy of well-established drugs like cisplatin or the topoisomerase inhibitors etoposide and topotecan. Non-cancer cells were affected only slightly by P8-D6. Moreover, no hepatotoxic effect in in vitro studies was detected.

Conclusion:

P8-D6 is a strong and rapid inductor of apoptosis and might be a novel treatment option for OvCa therapy.

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.

Multiple-therapy strategies via polysaccharides-based nano-systems in fighting cancer

Polysaccharide-based biomaterials (e.g., chitosan, dextran, hyaluronic acid, chondroitin sulfate and heparin) have received great attention in healthcare, particularly in drug delivery for tumor therapy. They are naturally abundant and available, outstandingly biodegradable and biocompatible, and they generally have negligible toxicity and low immunogenicity. In addition, they are easily chemically or physically modified. Therefore, PSs-based nanoparticles (NPs) have been extensively investigated for the enhancement of tumor treatment. In this review, we introduce the synthetic pathways of amphiphilic PS derivatives, which allow the constructs to self-assemble into NPs with various structures. We especially offer an overview of the emerging applications of self-assembled PSs-based NPs in tumor chemotherapy, photothermal therapy (PTT), photodynamic therapy (PDT), gene therapy and immunotherapy. We believe that this review can provide criteria for a rational and molecular level-based design of PS-based NPs, and comprehensive insight into the potential of PS-based NPs used in multiple cancer therapies.

Endogenous reactive oxygen species burst induced and spatiotemporally controlled multiple drug release by traceable nanoparticles for enhancing antitumor efficacy

Reactive oxygen species (ROS) are not only used as a therapeutic reagent in chemodynamic therapy (CDT), to stimulate the release of antineoplastic drugs, they can also be used to achieve a combined effect of CDT and chemotherapy to enhance anticancer effects. Herein, we synthesized a pH-responsive prodrug (PEG2k-NH-N-DOX), ROS-responsive prodrug (PEG2k-S-S-CPT-ROS), organic CDT agents (TPP-PEG2k-LND, TPP-PEG2k-TOS), and T1-enhanced magnetic resonance imaging contrast agents (Gd-DTPA-N16-16), and used them to encapsulate combrestatinA4 (CA4) to prepare traceable pH/ROS dual-responsive multifunctional nanoparticles (TLDCAG NPs) with endogenous ROS burst and spatiotemporally controlled multiple drug release ability. Firstly, TLDCAG NPs were accumulated in the tumor cell microenvironment via an enhanced permeability and retention (EPR) effect. Secondly, CA4 was released and specifically destroyed angiogenesis to facilitate the interaction between the tumor and the remaining TLDCG NPs. After accumulating in tumor cells, the TLDCG NPs could be destroyed under acidic conditions to quickly release doxorubicin (DOX), TPP-PEG2k-LND, and TPP-PEG2k-TOS. Thirdly, TPP-PEG2k-LND and TPP-PEG2k-TOS quickly targeted mitochondria, induced endogenous ROS bursts, reduced the mitochondrial membrane potential, and induced tumor cell apoptosis. Endogenous ROS can not only be used as a therapeutic reagent for CDT, but also can cut off the thioketal bond in PEG2k-S-S-CPT-ROS and release camptothecin (CPT). Finally, TLDCAG NPs were traced by magnetic resonance imaging (MRI). Furthermore, in vitro and vivo results indicate that the TLDCAG NPs have vigorous antitumor activity and negligible systemic toxicity. Therefore, the TLDCAG NPs provide an efficient strategy for enhancing antitumor efficacy.

Hyaluronan-based Multifunctional Nano-carriers for Combination Cancer Therapy

Hyaluronan (HA) is a natural linear polysaccharide that has excellent hydrophilicity, biocompatibility, biodegradability, and low immunogenicity, making it one of the most attractive biopolymers used for biomedical researches and applications. Due to the multiple functional sites on HA and its intrinsic affinity for CD44, a receptor highly expressed on various cancer cells, HA has been widely engineered to construct different drug-loading nanoparticles (NPs) for CD44-targeted anti-tumor therapy. When a cocktail of drugs is co-loaded in HA NP, a multifunctional nano-carriers could be obtained, which features as a highly effective and self-targeting strategy to combat cancers with CD44 overexpression. The HA-based multidrug nano-carriers can be a combination of different drugs, various therapeutic modalities, or the integration of therapy and diagnostics (theranostics). Up to now, there are many types of HA-based multidrug nano-carriers constructed by different formulation strategies, including drug co-conjugates, micelles, nano-gels and hybrid NP of HA and so on. This multidrug nano-carrier takes the full advantages of HA as an NP matrix, drug carriers and targeting ligand, representing a simplified and biocompatible platform to realize the targeted and synergistic combination therapy against the cancers. In this review, recent progress of HA-based multidrug nano-carriers for combination cancer therapy is summarized and the potential challenges for translational applications have been discussed.

Self-targeted polymersomal co-formulation of doxorubicin, camptothecin and FOXM1 aptamer for efficient treatment of non-small cell lung cancer

In spite of huge developments in cancer treatment, versatile combinational formulations of different chemotherapeutic agents to enhance anticancer activity while reducing systemic toxicity still remains a challenge. In this regard, in the current study, an amphiphilic hyaluronic acid-b-polycaprolactone diblock copolymer was synthesized using "click chemistry". The synthesized copolymer was self-assembled to form polymersomal structures for co-encapsulation of hydrophilic doxorubicin (DOX) and hydrophobic camptothecin (CPT) in their interior aqueous compartment and their bilayer, respectively with 1:10 and 1:1 ratios. The prepared polymersomal combinational formulation surrounded by hyaluronic acid brush as hydrophilic segment, could provide active targeting of the system against CD44 marker expressed on the surface of cancerous cells. The hyaluronic acid shell could also provide flexible chemistry for the conjugation of therapeutic FOXM1-specific DNA aptamer (Forkhead Box M1; against transcription factor FOXM1) on the surface of polymersomes in order to further suppress cancerous cell proliferation. The obtained results demonstrated that the prepared co-formulation provided sustained, controlled release of the entrapped drugs during 200 h. In vitro cytotoxicity experiments on non-small cell lung cancer, A549 and SK-MES-1 cell lines, demonstrated that the co-formulation of DOX and CPT provided synergistic effect and significantly higher cytotoxicity in comparison with free drugs. The cytotoxicity experiment also indicated that the aptamer conjugation on the co-formulations surface could significantly increase the cytotoxicity and induce apoptosis in combination therapy on both A549 and SK-MES-1 cell lines while aptamer-conjugated blank NPs did not show any cytotoxicity which emphasizes on the sensitization capability of the FOXM1 DNA aptamer against non-small cell lung cancer. Furthermore, it was shown that the co-formulation with or without aptamer renders the formulation specific tumor accumulation in vivo 24 h post-administration, assisting the combination synergy observed in vitro to be translated to in vivo antitumor efficacy. This combinatorial delivery platform strongly offers a novel approach for the synergistic controlled transportation of several chemotherapeutics for the treatment of non-small cell lung cancer.

A dual macrophage polarizer conjugate for synergistic melanoma therapy

Tumor associated macrophages (TAMs) play a paradoxical role in the fate of aggressive tumors like melanoma. Immune modulation of TAMs from the tumor-permissive M2 phenotype to antitumoral M1 phenotype is an emerging attractive approach in melanoma therapy. Resiquimod is a TLR7/8 agonist that shifts the polarization of macrophages towards M1 phenotype. Bexarotene (BEX) is a retinoid that induce the expression of phagocytic receptors in macrophages besides its ability to downregulate the M2 polarization. However, the clinical use of both agents is hindered by poor pharmacokinetic properties. Here, for the first time we repurposed BEX based on its immunomodulatory properties and combined it with RES by designing hyaluronic acid (HA) conjugates of both drugs that act synergistically as a dual macrophage polarizer to promote the M1 phenotype and suppress the M2 phenotype. This combination enhanced the macrophage secretion of proinflammatory cytokines (IL-6 and TNF-α), while suppressing the production of tumor promoting cytokine CCL22. It enhanced the macrophage phagocytic ability and showed superior inhibitory effects against B16F10 cells. In vivo studies on a mouse melanoma model confirmed the superiority of the dual conjugate compared to the single HA-drug conjugates in suppressing the tumor growth. Immunoprofiling of the excised tumors revealed a significant increase in the M1/M2 ratio of TAMs in mice treated with the dual conjugate. Our intravenously injectable HA conjugate of RES and BEX provides a promising immunotherapeutic combination strategy for resetting the M1/M2 ratio, supporting the tumoricidal activity of TAMs for effective melanoma treatment.

A traceable, GSH/pH dual-responsive nanoparticles with spatiotemporally controlled multiple drugs release ability to enhance antitumor efficacy

Constructing highly efficient and multifunctional nanoparticles to overcome the multiple challenges of targeted drug delivery is a new strategy urgently needed in tumor therapy. Here, we synthesized pH-responsive prodrug (PEG_2K-NH-N-DOX), GSH-responsive prodrug (PEG_2K-S-S-CPT), folate-receptor targeting polymers (FA-PEG_2K-L8, FA-PEG_2K-TOS) and T1-enhanced magnetic resonance imaging contrast agents (Gd-DTPA-N16-16), used to encapsulate combrestatinA4 (CA4) to prepare multifunctional nanoparticles (FTDCAG NPs). Unlike other nanoparticles, FTDCAG NPs contains three drugs with the ability to control the release in time and space, which can maximize the effectiveness of precise cancer chemotherapy. We first confirmed that specific binding between FTDCAG NPs and overexpressed folate-receptor cells by flow cytometry and confocal laser scanning microscopy. We then investigated the spatiotemporally controlled release ability of FTDCAG NPs loaded with doxorubicin (DOX), CA4 and camptothecin (CPT). Relative to pH = 7.4, the release efficiency of CA4 in the pH = 6.5 increased by 63.4 %. The first released CA4 is able to destroy the angiogenesis and help tumor cells to be exposed to the remaining FTDCG NPs. After being internalized into the tumor cells, FTDCG NPs is disassembled and the CPT and DOX were released due to the increase of intracellular GSH concentration and the decrease of pH value. Besides, the relaxation time of FTDCAG NPs is 3.86 times that of clinical Gd-DTPA, and the in vitro and vivo T1-weighted imaging is brighter, which can be used to trace the nanoparticles by MRI. Therefore, FTDCAG NPs provide an efficient strategy for the design of multifunctional drug delivery systems for enhancing antitumor efficacy.

Hyaluronic acid prodrug micelles for tumour therapy

Hyaluronic acid (HA), an important component of the extracellular matrix, has high water solubility and biocompatibility, and good application prospects in biomedicine. Especially in tumour treatment, prodrug polymer micelles prepared from HA and chemotherapeutics can increase water solubility, prolong drug release time, improve organ distribution and therapeutic effects, and show good tumour targeting and biocompatibility. Therefore, this study introduces strategies for using HA to prepare prodrug polymer micelles and discusses recent research on HA prodrug micelles for antitumor applications.

Dual-Drug Backboned Polyprodrug with a Predefined Drug Combination for Synergistic Chemotherapy

The codelivery of drugs at specific optimal ratios to cancer cells is vital for combination chemotherapy. However, most of the current strategies are unable to coordinate the loading and release of drug combinations to acquire precise and controllable synergistic ratios. In this work, we designed an innovative dual-drug backboned and reduction-sensitive polyprodrug PEG-P(MTO-ss-CUR) containing the anticancer drugs mitoxantrone (MTO) and curcumin (CUR) at an optimal synergistic ratio to reverse drug resistance. Due to synchronous drug activation and polymer backbone degradation, drug release at the predefined ratio with a synergistic anticancer effect was demonstrated by in vitro and in vivo experiments. Therefore, the dual-drug delivery system developed in this work provides a novel and efficient strategy for combination chemotherapy.

Hyaluronic acid-doxorubicin nanoparticles for targeted treatment of colorectal cancer

Colorectal cancer, common in both men and women, occurs when tumors form in the linings of the colon. Common treatments of colorectal cancer include surgery, chemotherapy, and radiation therapy; however, many colorectal cancer treatments often damage healthy tissues and cells, inducing severe side effects. Conventional chemotherapeutic agents such as doxorubicin (Dox) can be potentially used for the treatment of colorectal cancer; however, they suffer from limited targeting and lack of selectivity. Here, we report that doxorubicin complexed to hyaluronic acid (HA) (HA-Dox) exhibits an unusual behavior of high accumulation in the intestines for at least 24 hr when injected intravenously. Intravenous administrations of HA-Dox effectively preserved the mucosal epithelial intestinal integrity in a chemical induced colon cancer model in mice. Moreover, treatment with HA-Dox decreased the expression of intestinal apoptotic and inflammatory markers. The results suggest that HA-Dox could effectively inhibit the development of colorectal cancer in a safe manner, which potentially be used a promising therapeutic option.

Glycyrrhetinic Acid-Functionalized Mesoporous Silica Nanoparticles for the Co-Delivery of DOX/CPT-PEG for Targeting HepG2 Cells

A pH-triggered mesoporous silica nanoparticle (MSN)-based nano-vehicle for the dual delivery of doxorubicin (DOX)/camptothecin-PEG (CPT-PEG) has been prepared. To enhance its selectivity, the nanoparticles were decorated with glycyrrhetinic acid (GA) to target HepG2 cells. The highly insoluble CPT was derivatized with a reductive-cleavable PEG chain to improve its loading within the MSN. The preparation of these particles consisted of four steps. First, CPT-PEG was loaded within the pores of the MSN. Then, dihydrazide polyethylene glycol chains were introduced onto the surface of an aldehyde-functionalized MSN by means of a hydrazone bond. Afterwards, DOX was covalently attached to the other end of the dihydrazide polyethylene glycol chains. Finally, the resulting nanoparticles were decorated with GA by formation of an imine bond between the amino group of DOX and a benzaldehyde-GA derivative. The system was stable at physiological conditions and the release of both drugs was negligible. However, at acidic pH, a burst release of DOX and a gradual release of CPT-PEG takes place. GA-decorated drug delivery systems (DDS) selectively internalizes into HepG2. In vitro tests demonstrated that this system shows a great cytotoxicity towards HepG2 cells. Furthermore, glutathione cleavage of CPT prodrug assures the formation of free CPT leading to a synergistic effect in combination with DOX.

A novel cell membrane-cloaked magnetic nanogripper with enhanced stability for drug discovery

Cell membrane-cloaked nanotechnology has attracted increasing attention owing to its unique bionic properties, such as specific recognition and biocompatibility conferred by the integrated membrane structure and receptors. However, this technology is limited by the dissociation of the cell membrane from its carrier. Here, we report a novel type of cell membrane-cloaked modified magnetic nanoparticle with good stability in drug discovery. High α1A-adrenergic receptor (α1A-AR) expressing HEK293 cell membrane-cloaked magnetic nanogrippers (α1A/MNGs) were used as a platform for the specific targeting and binding of α1A-AR antagonists as candidate bioactive compounds from traditional Chinese medicine (TCM). Furthermore, using a dynamic covalent bonding approach, α1A/MNGs showed great stability with positive control drug recoveries of α1A/MNGs showing almost no decline after use in five adsorption-desorption cycles. Moreover, the α1A/MNGs possessed a unilamellar membrane with magnetic features and exhibited good binding capacity and selectivity. Ultimately, TCM and pharmacological studies of the bioactivity of the screened compounds confirmed the considerable targeting and binding capability of α1A/MNGs. Application of aldehyde group modification in this drug-targeting concept further improved biomaterial stability and paves the way for the development of new drug discovery strategies. More importantly, the successful application of α1A/MNGs provides new insights into methodologies to improve the integration of cell membranes with the nanoparticle platform.

Recent advances in composites based on cellulose derivatives for biomedical applications

Cellulose derivatives represent a viable alternative to pure cellulose due to their solubility in water and common organic solvents. This, coupled with their low cost, biocompatibility, and biodegradability, makes them an attractive choice for applications related to the biomedicine and bioanalysis area. Cellulose derivatives-based composites with improved properties were researched as films and membranes for osseointegration, hemodialysis and biosensors, smart textile fibers, tissue engineering scaffolds, hydrogels and nanoparticles for drug delivery. The different preparation strategies of these polymeric composites as well as the most recent available experimental results were described in this review. General aspects such as structure and properties of cellulose extracted from plants or bacterial sources, types of cellulose derivatives and their synthesis methods were also discussed. Finally, the future perspectives related to composites based on cellulose derivatives were highlighted and some conclusions regarding the reviewed applications were drawn.

Modified gaphene oxide (GO) particles in peptide hydrogels: a hybrid system enabling scheduled delivery of synergistic combinations of chemotherapeutics

The scheduled delivery of synergistic drug combinations is increasingly recognized as highly effective against advanced solid tumors. Of particular interest are composite systems that release a sequence of drugs with defined kinetics and molar ratios to enhance therapeutic effect, while minimizing the dose to patients. In this work, we developed a homogeneous composite comprising modified graphene oxide (GO) nanoparticles embedded in a Max8 peptide hydrogel, which provides controlled kinetics and molar ratios of release of doxorubicin (DOX) and gemcitabine (GEM). First, modified GO nanoparticles (tGO) were designed to afford high DOX loading and sustained release (18.9% over 72 h and 31.4% over 4 weeks). Molecular dynamics simulations were utilized to model the mechanism of DOX loading as a function of surface modification. In parallel, a Max8 hydrogel was developed to release GEM with faster kinetics and achieve a 10-fold molar ratio to DOX. The selected DOX/tGO nanoparticles were suspended in a GEM/Max8 hydrogel matrix, and the resulting composite was tested against a triple negative breast cancer cell line, MDA-MB-231. Notably, the composite formulation afforded a combination index of 0.093 ± 0.001, indicating a much stronger synergism compared to the DOX-GEM combination co-administered in solution (CI = 0.396 ± 0.034).

Functionalized mesoporous silica nanoparticles with 2,7,12,17-tetraphenylporphycene

Mesoporous silica nanoparticles decorated with 2,7,12,17-tetraphenylporphycene have been prepared by reaction of aminated nanoparticles with 9-(glutaric [Formula: see text]-succinimidylesteramide)-2,7,12,17-tetraphenylporphycene. The as-prepared nanoparticles were characterized by UV-vis spectroscopy, DLS and TEM.

PVA reinforced gossypolone and doxorubicin π-π stacking nanoparticles towards tumor targeting and ultralow dose synergistic chemotherapy

To improve the tumor synergistic therapeutic effects of carrier-free dual-drug delivery systems and realize ultralow dose administration, we developed a tumor targeting and high-efficiency synergistic chemotherapy system (HA-Gn@DPGn NPs) based on polyvinyl alcohol (PVA) reinforced gossypolone (Gn) and doxorubicin (DOX) π-π stacking nanoparticles (DPGn NPs), in which PVA filled the gaps between Gn and DOX and bridged Gn and DOX tightly. Hyaluronic acid modifier hyaluronic acid-gossypolone (HA-Gn) was covered on the surface of DPGn NPs to form HA-Gn@DPGn NPs that procured active targeting properties. This system presented a spherical shape with a uniform hydrodynamic size of 87 ± 6.8 nm, a high drug loading of 80.31%, and high stability. FTIR and UV spectra demonstrated that HA-Gn was covered on the surface of the system and showed significant π-π stacking properties. A considerably low combination index of Gn and DOX (0.1862) was determined at an ultra-low dose of DOX under a Gn : DOX ratio of 50 : 1. HA-Gn@DPGn NPs also demonstrated excellent tumor synergistic therapeutic efficacy (TIR > 87%) at an ultralow dose of DOX and Gn. This system demonstrates high tumor comprehensive synergistic therapeutic efficacy at an ultralow drug dose with multiple favorable therapeutic characteristics, including negligible side effects, tumor targeting ability and thermal-responsive drug release, and thus has considerable potential for tumor synergistic therapy.

A nanoscale photothermal agent based on a metal-organic coordination polymer as a drug-loading framework for effective combination therapy

Metallic materials are widely emerging as photothermal agents owing to their superior photothermal transduction efficiency and satisfactory photostability. In this study, an iron-based coordination polymer (Fe-CNP) loaded with doxorubicin (DOX) was assessed as a dual-function agent for photothermal therapy (PTT) and tumor-targeted chemotherapy. Fe-CNPs were synthesized by a one-step coordination reaction between Fe³⁺, hydrocaffeic acid, and dopamine-modified hyaluronic acid. A drug-loading method was developed to entrap DOX within Fe-CNPs through the formation of coordination bonds by Fe³⁺ and DOX (Scheme 1). DOX release was rapidly triggered in the cellular acidic environment and further enhanced by hyperpyrexia in the part of tumor, which will kill the remaining tumor cells after PTT. Animal experiments demonstrated complete inhibition of tumor growth without recurrence in 21 days after injection of DOX@Fe-CNPs with NIR laser irradiation. These results confirmed the enhanced anti-tumor efficiency of the chemo-photothermal nanosystem. Our work may reveal a photothermal coordination polymer as a drug-loading framework and highlight the development of metal-organic materials in combined chemo-photothermal therapy. STATEMENT OF SIGNIFICANCE: Photothermal therapy (PTT), which could directly act on tumors, has been considered as a promising treatment method for cancer. The combination of PTT with chemotherapy is attracting tremendous attention because such advanced application can achieve personalized precise medicine. Unfortunately, most PTT materials have photobleaching property, which results in reduced photothermal efficiency. Furthermore, their clinical applications also suffer from low loading capacity of chemotherapeutic drugs or nonbiodegradability in the biological system. In this study, we hypothesized that iron-based coordination polymers (Fe-CNPs) could function dually as agents to deliver both PTT and tumor-targeted chemotherapy by coordination loading of the chemotherapeutic drug doxorubicin (DOX). Our work may open up new avenues to rationally design versatile platforms for photothermal-chemotherapy to obtain synergistically enhanced therapeutic efficacy.

Multifunctional Albumin-Stabilized Gold Nanoclusters for the Reduction of Cancer Stem Cells

Controlled delivery of multiple chemotherapeutics can improve the effectiveness of treatments and reduce side effects and relapses. Here in, we used albumin-stabilized gold nanoclusters modified with doxorubicin and SN38 (AuNCs-DS) as combined therapy for cancer. The chemotherapeutics are conjugated to the nanostructures using linkers that release them when exposed to different internal stimuli (Glutathione and pH). This system has shown potent antitumor activity against breast and pancreatic cancer cells. Our studies indicate that the antineoplastic activity observed may be related to the reinforced DNA damage generated by the combination of the drugs. Moreover, this system presented antineoplastic activity against mammospheres, a culturing model for cancer stem cells, leading to an efficient reduction of the number of oncospheres and their size. In summary, the nanostructures reported here are promising carriers for combination therapy against cancer and particularly to cancer stem cells.

Role of synergy and immunostimulation in design of chemotherapy combinations: An analysis of doxorubicin and camptothecin

Combination chemotherapy is often employed to improve therapeutic efficacies of drugs. However, traditional combination regimens often utilize drugs at or near-their maximum tolerated doses (MTDs), elevating the risk of dose-related toxicity and impeding their clinical success. Further, high doses of adjuvant or neoadjuvant chemotherapies can cause myeloablation, which compromises the immune response and hinders the efficacy of chemotherapy as well as accompanying treatments such as immunotherapy. Clinical outcomes can be improved if chemotherapy combinations are designed to reduce the overall doses without compromising their therapeutic efficacy. To this end, we investigated a combination of camptothecin (CPT) with doxorubicin (DOX) as a low-dose treatment option for breast cancer. DOX-CPT combinations were synergistic in several breast cancer cell lines in vitro and one particular ratio displayed extremely high synergy on human triple negative breast cancer cells (MDA-MB-231). This combination led to excellent long-term survival of mice bearing MDA-MB-231 tumors at doses roughly five-fold lower than the reported MTD values of its constituent drugs. Impact of low dose DOX-CPT treatment on local tumor immune environment was assessed in immunocompetent mice bearing breast cancer (4T1) tumors. The combination was not only superior in inhibiting the disease progression compared to individual drugs, but it also generated a more favorable antitumor immunogenic response. Engineering DOX and CPT ratios to manifest synergy enables treatment at doses much lower than their MTDs, which could ultimately facilitate their translation into the clinic as a promising combination for breast cancer treatment.

The role of nanoparticles in the improvement of systemic anticancer drug delivery

The systemic delivery of drugs to the body via circulation after oral administration is a preferred method of drug administration during cancer treatment given its ease of implementation. However, the physicochemical properties of many current anticancer drugs limit their effectiveness when delivered by systemic routes. The use of nanoparticles (NPs) has emerged as an effective means of overcoming the inherent limitations of systemic drug delivery. We provide herein an overview of various NP formulations that facilitate improvements in the efficacy of various anticancer drugs compared with the free drug. This review will be useful to the reader who is interested in the role NP technology is playing in shaping the future of chemotherapeutic drug delivery and disease treatment.

Polymeric Co-Delivery Systems in Cancer Treatment: An Overview on Component Drugs' Dosage Ratio Effect

Multiple factors are involved in the development of cancers and their effects on survival rate. Many are related to chemo-resistance of tumor cells. Thus, treatment with a single therapeutic agent is often inadequate for successful cancer therapy. Ideally, combination therapy inhibits tumor growth through multiple pathways by enhancing the performance of each individual therapy, often resulting in a synergistic effect. Polymeric nanoparticles prepared from block co-polymers have been a popular platform for co-delivery of combinations of drugs associated with the multiple functional compartments within such nanoparticles. Various polymeric nanoparticles have been applied to achieve enhanced therapeutic efficacy in cancer therapy. However, reported drug ratios used in such systems often vary widely. Thus, the same combination of drugs may result in very different therapeutic outcomes. In this review, we investigated polymeric co-delivery systems used in cancer treatment and the drug combinations used in these systems for synergistic anti-cancer effect. Development of polymeric co-delivery systems for a maximized therapeutic effect requires a deeper understanding of the optimal ratio among therapeutic agents and the natural heterogenicity of tumors.

Synergistic antitumor efficacy of hybrid micelles with mitochondrial targeting and stimuli-responsive drug release behavior

The term synergism means that the overall therapeutic benefits should be greater than the sum of the effects of individual agents and that the optimal therapeutic efficacy can be achieved at reduced doses. Micellar systems usually fail to deliver multiple drugs to target sites at synergistic doses and thus are not able to maximize the antitumor efficacy. In the current study, we demonstrate a strategy to coordinate the release of camptothecin (CPT) and α-tocopheryl succinate (TOS) from hybrid micelles for nucleus and mitochondrion interferences. TOS is decorated with cationic triphenylphosphonium (TPP) to promote the targeting capability of TOS-TPP to mitochondria. The combination of CPT and TOS-TPP shows strong synergistism with a combination index of 0.186. Hyaluronic acid (HA) is conjugated with CPT or TOS-TPP via disulfide linkages for tumor cell targeting and intracellular reduction-triggered release. Both conjugates either separately self-assemble into M_C and M_T micelles, or are blended at different ratios to form M_C-T hybrid micelles. In response to elevated intracellular glutathione levels, the coordinated release of CPT and TOS-TPP from M_C-T results in a combination index of 0.26 and the dose-reduction indexes of CPT and TOS are 7.7 and 3.4, respectively. Compared with M_C and M_T, M_C-T micelles with 5 fold lower doses exhibit higher intracellular reactive oxygen species (ROS) levels, comparable tumor growth inhibition and animal survival, indicating no hematologic and intestinal toxicities. Moreover, the HA conjugates of M_C-T are linked to polylactide via acid-labile linkages and electrospun into short fibers (M_C-T@SF) as an injectable depot to release M_C-T in response to the acidic tumor microenvironment. At a predetermined synergistic ratio, M_C-T@SF with 5 fold lower doses achieves antitumor profiles comparable to those of individual micelle-loaded short fibers. Therefore, the hybrid micelles and micelle-releasing short fibers represent a feasible strategy to synergistically enhance the therapeutic efficacy and enable significant reduction in effective doses of chemotherapeutic agents.

Therapeutic polymeric nanomedicine: GSH-responsive release promotes drug release for cancer synergistic chemotherapy

To obtain an efficient dual-drug release and enhance therapeutic efficiency for combination chemotherapy, a glutathione (GSH)-responsive therapeutic amphiphilic polyprodrug copolymer (mPEG-b-PCPT) is synthesized to load doxorubicin (DOX) via hydrophobic and π–π stacking interaction. In this nanomedicine system (mPEG-b-PCPT/DOX), the ratio of the two drugs can be easily modulated by changing the loading content of DOX. The in vitro drug release curves and laser confocal images suggested that the release of CPT and DOX is induced through a “release promotes release strategy”: after internalization into tumor cells, the disulfide bonds in the nanomedicine are cleaved by glutathione (GSH) in the cytoplasm and then lead to the release of CPT. Meanwhile, the disassembly of nanomedicine immediately promotes the co-release of DOX. The optimum dose ratio of CPT and DOX is evaluated via the combination index (CI) value using HepG-2 cells. The results of cell apoptosis and cell viability prove the better synergistic efficiency of the nanomedicine than free drugs at the optimum dose ratio of 1. Consequently, this stimuli-responsive synergistic chemotherapy system provides a direction for the fabrication of nanomedicines possessing promising potential in clinical trials.

In the GSH-responsive doxorubicin loading camptothecin prodrug nanomedicine, easy modulation of the dose ratio and controlled co-release were achieved, and the synergistic effect was significantly improved.