A multiple environment-sensitive prodrug nanomicelle strategy based on chitosan graftomer for enhanced tumor therapy of gambogic acid

Multifunctional Biomimetic Liposomes with Improved Tumor-Targeting for TNBC Treatment by Combination of Chemotherapy, Antiangiogenesis and Immunotherapy

Triple negative breast cancer (TNBC) featuring high relapses and metastasis shows limited clinical therapeutic efficiency with chemotherapy for the extremely complex tumor microenvironment, especially angiogenesis and immunosuppression. Combination of antiangiogenesis and immunotherapy holds promise for effective inhibition of tumor proliferation and invasion, while it remains challenging for specific targeting drug delivery to tumors and metastatic lesions. Here, a multifunctional biomimetic liposome loading Gambogic acid (G/R-MLP) is developed using Ginsenoside Rg3 (Rg3) to substitute cholesterol and cancer cell membrane coating, which is designed to increase long-circulating action by a low immunogenicity and specifically deliver gambogic acid (GA) to tumor site and metastatic lesions by homologous targeting and glucose transporter targeting. After G/R-MLP accumulates in the primary tumors and metastatic nodules, it synergistically enhances the antitumor efficacy of GA, effectively suppressing the tumor growth and lung metastasis by killing tumor cells, inhibiting tumor cell migration and invasion, achieving antiangiogenesis and improving the antitumor immunity. All in all, the strategy combining chemotherapy, antiangiogenesis, and immunotherapy improves therapeutic efficiency and prolonged survival, providing a new perspective for the clinical treatment of TNBC.

Enhancing oral delivery and anticancer efficacy of 7-ethyl-10-hydroxycamptothecin through self-assembled micelles of deoxycholic acid grafted N'-nonyl-trimethyl chitosan

Irinotecan (CPT-11) is used as a first or second-line chemotherapy drug for the treatment and management of colorectal cancers. In vitro studies have shown that 7-ethyl-10-hydroxycamptothecin (SN38), the active metabolite of CPT-11, displays promising anticancer efficacy. However, its poor aqueous solubility and hydrolytic degradation result in its lower oral bioavailability and impracticable clinical application. To overcome these limitations, a novel amphiphilic chitosan derivative, deoxycholic acid decorated N'-nonyl-trimethyl chitosan, was synthesized. Nano-micelles loaded with SN38 were subsequently prepared to enhance the bioavailability and anti-tumor efficacy of the drug through oral administration. The nano-micelles demonstrated improved dilution stability, enhanced greater mucosal adherence, significant P-gp efflux inhibition, and increased drug transport in the intestine by paracellular and transcellular pathways. Consequently, both the in vivo pharmacokinetic profile and therapeutic efficacy of SN38 against cancer were substantially improved via the micellar system. Thus, the developed polymeric micelles can potentially enhance the SN38 oral absorption for cancer therapy, offering prospective avenues for further exploration.

Emerging tendencies for the nano-delivery of gambogic acid: a promising approach in oncotherapy

Despite the advancements in cancer therapies during the past few years, chemo/photo resistance, severe toxic effects, recurrence of metastatic tumors, and non-selective targeting remain incomprehensible. Thus, much effort has been spent exploring natural anticancer compounds endowed with biosafety and high effectiveness in cancer prevention and therapy. Gambogic acid (GA) is a promising natural compound in cancer therapy. It is the major xanthone component of the dry resin extracted from the Garcinia hanburyi Hook. f. tree. GA has significant antiproliferative effects on different types of cancer, and it exerts its anticancer activities through various pathways. Nonetheless, the clinical translation of GA has been hampered, partly due to its water insolubility, low bioavailability, poor pharmacokinetics, rapid plasma clearance, early degradation in blood circulation, and detrimental vascular irritation. Lately, procedures have been invented demonstrating the ability of nanoparticles to overcome the challenges associated with the clinical use of natural compounds both in vitro and in vivo. This review sheds light on the recent emerging trends for the nanodelivery of GA to cancer cells. To the best of our knowledge, no similar recent review described the different nanoformulations designed to improve the anticancer therapeutic activity and targeting ability of GA.

Construction of intelligent drug delivery system based on polysaccharide-derived polymer micelles: A review

Micelles are nanostructures developed via the spontaneous assembly of amphiphilic polymers in aqueous systems, which possess the advantages of high drug stability or active-ingredient solubilization, targeted transport, controlled release, high bioactivity, and stability. Polysaccharides have excellent water solubility, biocompatibility, and degradability, and can be modified to achieve a hydrophobic core to encapsulate hydrophobic drugs, improve drug biocompatibility, and achieve regulated delivery of the loaded drug. Micelles drug delivery systems based on polysaccharides and their derivatives show great potential in the biomedical field. This review discusses the principles of self-assembly of amphiphilic polymers and the formation of micelles; the preparation of amphiphilic polysaccharides is described in detail, and an overview of common polysaccharides and their modifications is provided. We focus on the review of strategies for encapsulating drugs in polysaccharide-derived polymer micelles (PDPMs) and building intelligent drug delivery systems. This review provides new research directions that will help promote future research and development of PDPMs in the field of drug carriers.

Caged Polyprenylated Xanthones in Garcinia hanburyi and the Biological Activities of Them

The previous phytochemical analyses of Garcinia hanburyi revealed that the main structural characteristic associated with its biological activity is the caged polyprenylated xanthones with a unique 4-oxatricyclo [4.3.1.03,7] dec-2-one scaffold, which contains a highly substituted tetrahydrofuran ring with three quaternary carbons. Based on the progress in research of the chemical constituents, pharmacological effects and modification methods of the caged polyprenylated xanthones, this paper presents a preliminary predictive analysis of their drug-like properties based on the absorption, distribution, metabolism, excretion and toxicity (ADME/T) properties. It was found out that these compounds have very similar pharmacokinetic properties because they possess the same caged xanthone structure, the 9,10-double bond in a,b-unsaturated ketones are critical for the antitumor activity. The author believes that there is an urgent need to seek new breakthroughs in the study of these caged polyprenylated xanthones. Thus, the research on the route of administration, therapeutic effect, structural modification and development of such active ingredients is of great interest. It is hoped that this paper will provide ideas for researchers to develop and utilize the active ingredients derived from natural products.

Oral delivery of pectin-chitosan hydrogels entrapping macrophage-targeted curcumin-loaded liposomes for the treatment of ulcerative colitis

The oral delivery of anti-inflammatory drugs has been a promising strategy for enhancing the clinical efficacy of ulcerative colitis (UC) treatment strategies. However, achieving site specific drug delivery to colon tissues and target cells is a challenging task for formulation scientists. In this study, macrophages-targeted liposome-loaded pectin-chitosan hydrogels were developed for UC treatment via oral administration. Folate-functionalized cholesterol was synthesized as lipid membrane materials for the liposomes containing curcumin (CUR). The incorporation of the liposomal CUR within pectin-chitosan hydrogels resulted in a matrix that exhibited considerable sensitivity to colonic enzymes during in vitro release. The targeted delivery of hybrids was able to effectively reach macrophages. They also showed enhanced capability to downregulate TNF-α, IL-6, and IL-1β in the lipopolysaccharide-induced Raw 264.7 cells model. DSS-induced mice modelshowed improved anti-UC effects, including accelerated mucosal repair and decreased inflammation and modulate the immune balance in the intestinal tissue of mice with colitis, which may be attributable to increased drug accumulation in the colonic lumen and improved internalization to target cells. Therefore, the incorporation of folate-modified liposomes containing CUR and pectin-chitosan physical hydrogels could potentially serve as a favorable approach for treating UC through an oral colon-targeted drug delivery system.

Dual functionalized hyaluronic acid micelles loading paclitaxel for the therapy of breast cancer

Although many carriers for the delivery of chemotherapeutic drugs have been investigated, the disadvantages of passive targeting and uncontrolled drug release limit their utility. Herein, hyaluronic acid (HA) was hydrophobically modified to serve as a carrier for binding to cluster determinant 44 (CD44) overexpressed on tumor cell surfaces. Specifically, after deacetylation, HA was grafted to dodecylamine or tetradecylamine to afford amphiphilic zwitterionic polymer micelles, designated dHAD and dHAT, respectively, for the delivery of paclitaxel (PTX). The micelles were negatively charged at pH 7.4 and positively charged at pH 5.6, and this pH sensitivity facilitated PTX release under acidic conditions. The cell uptake efficiencies of the dHAD-PTX and dHAT-PTX micelles by MCF-7 cells after 4 h of incubation were 96.9% and 95.4%, respectively, and their affinities for CD44 were twice that of HA. Furthermore, the micelles markedly inhibited tumor growth both in vitro and in vivo, with IC50 values of 1.943 μg/mL for dHAD-PTX and 1.874 μg/mL for dHAT-PTX for MCF-7 cells; the tumor inhibition rate of dHAD-PTX (92.96%) was higher than that of dHAT-PTX (78.65%). Importantly, dHAD and dHAT micelles showed negligible systemic toxicity. Our findings suggest that these micelles are promising delivery vehicles for antitumor drugs.

Research Progress on Stimulus-Responsive Polymer Nanocarriers for Cancer Treatment

As drug carriers for cancer treatment, stimulus-responsive polymer nanomaterials are a major research focus. These nanocarriers respond to specific stimulus signals (e.g., pH, redox, hypoxia, enzymes, temperature, and light) to precisely control drug release, thereby improving drug uptake rates in cancer cells and reducing drug damage to normal cells. Therefore, we reviewed the research progress in the past 6 years and the mechanisms underpinning single and multiple stimulus-responsive polymer nanocarriers in tumour therapy. The advantages and disadvantages of various stimulus-responsive polymeric nanomaterials are summarised, and the future outlook is provided to provide a scientific and theoretical rationale for further research, development, and utilisation of stimulus-responsive nanocarriers.

The Role of Integrins for Mediating Nanodrugs to Improve Performance in Tumor Diagnosis and Treatment

Integrins are heterodimeric transmembrane proteins that mediate adhesive connections between cells and their surroundings, including surrounding cells and the extracellular matrix (ECM). They modulate tissue mechanics and regulate intracellular signaling, including cell generation, survival, proliferation, and differentiation, and the up-regulation of integrins in tumor cells has been confirmed to be associated with tumor development, invasion, angiogenesis, metastasis, and therapeutic resistance. Thus, integrins are expected to be an effective target to improve the efficacy of tumor therapy. A variety of integrin-targeting nanodrugs have been developed to improve the distribution and penetration of drugs in tumors, thereby, improving the efficiency of clinical tumor diagnosis and treatment. Herein, we focus on these innovative drug delivery systems and reveal the improved efficacy of integrin-targeting methods in tumor therapy, hoping to provide prospective guidance for the diagnosis and treatment of integrin-targeting tumors.

pH/reduction dual-responsive hyaluronic acid-podophyllotoxin prodrug micelles for tumor targeted delivery

Polymer-based prodrug nanocarriers with tumor-targeting and controlled-release properties are in great demand for enhanced cancer treatment. Hyaluronic acid (HA), which has excellent biocompatibility and targeting ability for cluster determinant 44 (CD44), has been proposed for delivering drugs that have poor solubility and high toxicity. Herein, podophyllotoxin (PPT) was conjugated to HA via ester and disulfide linkages to construct a pH- and reduction-responsive prodrug (HA-S-S-PPT). The micelles self-assembled from HA-S-S-PPT prodrug efficiently accumulated at tumor site due to HA receptor-mediated endocytosis. HA-S-S-PPT micelles exhibited 33.1% higher cumulative release than HA-NH-CO-PPT micelles (sensitive only to pH) owing to their dual responsiveness to pH and reduction. HA-S-S-PPT micelles achieved excellent antitumor activity in vivo, with the tumor inhibition rate reaching 92%, significantly higher than that of HA-NH-CO-PPT micelles (65%), and negligible systemic toxicity. This controllable-targeting nanoparticle system provides a potential platform for clinical application of PPT.

Research Progress in the Field of Gambogic Acid and Its Derivatives as Antineoplastic Drugs

Gambogic acid (GA) is a natural product with a wide range of pharmacological properties. It plays an important role in inhibiting tumor growth. A large number of GA derivatives have been designed and prepared to improve its shortcomings, such as poor water solubility, low bioavailability, poor stability, and adverse drug effects. So far, GA has been utilized to develop a variety of active derivatives with improved water solubility and bioavailability through structural modification. This article summarized the progress in pharmaceutical chemistry of GA derivatives to provide a reference and basis for further study on structural modifications of GA and expansion of its clinical applications.

pH-sensitive hyaluronic acid-targeted prodrug micelles constructed via a one-step reaction for enhanced chemotherapy

Although many chemotherapy prodrugs have been developed for tumor therapy, non-targeted delivery, uncontrolled release and tedious construction procedure of prodrugs still limit their clinical application in tumor treatment. In this work, hyaluronic acid (HA) which has tumor-targeting ability was used to conjugate to antitumor drug podophyllotoxin (PPT) to construct a pH-sensitive prodrug named HA-CO-O-PPT just via a one-step esterification reaction. The HA-CO-O-PPT spontaneously assembled into nano spherical micelles in aqueous medium, which had outstanding serum stability and blood compatibility. The obtained prodrug micelles (named HP micelles) exhibited a pH-responsive drug release mode with cumulative release reaching 81.2% due to their dissociation in response to acid stimulus, and had a high cellular uptake efficiency beyond 97% owing to HA receptor-mediated targeting. Furthermore, it was found that the prodrug micelles showed excellent antitumor activities in vivo with the tumor inhibition ratio up to 85% and negligible systemic toxicity. Accordingly, the pH-responsive HP micelles constructed by a simple one-step reaction, could be a promising candidate as a chemotherapeutic agent for cancer therapy.

Recent Advances in Chitosan and its Derivatives in Cancer Treatment

Cancer has become a main public health issue globally. The conventional treatment measures for cancer include surgery, radiotherapy and chemotherapy. Among the various available treatment measures, chemotherapy is still one of the most important treatments for most cancer patients. However, chemotherapy for most cancers still faces many problems associated with a lot of adverse effects, which limit its therapeutic potency, low survival quality and discount cancer prognosis. In order to decrease these side effects and improve treatment effectiveness and patient’s compliance, more targeted treatments are needed. Sustainable and controlled deliveries of drugs with controllable toxicities are expected to address these hurdles. Chitosan is the second most abundant natural polysaccharide, which has excellent biocompatibility and notable antitumor activity. Its biodegradability, biocompatibility, biodistribution, nontoxicity and immunogenicity free have made chitosan become a widely used polymer in the pharmacology, especially in oncotherapy. Here, we make a brief review of the main achievements in chitosan and its derivatives in pharmacology with a special focus on their agents delivery applications, immunomodulation, signal pathway modulation and antitumor activity to highlight their role in cancer treatment. Despite a large number of successful studies, the commercialization of chitosan copolymers is still a big challenge. The further development of polymerization technology may satisfy the unmet medical needs.

A Co-delivery System Based on a Dimeric Prodrug and Star-Shaped Polymeric Prodrug Micelles for Drug Delivery

Chemotherapy is one of the commonly used therapies for the treatment of malignant tumors. Insufficient drug-loading capacity is the major challenge for polymeric micelle-based drug delivery systems of chemotherapy. Here, the redox-responsive star-shaped polymeric prodrug (PSSP) and the dimeric prodrug of paclitaxel (PTX) were prepared. Then the dimeric prodrug of PTX (diPTX, diP) was loaded into the core of the star-shaped polymeric prodrug micelles of PSSP by hydrophobic interaction forming the redox-responsive prodrug micelles of diPTX@PSSP for intracellular drug release in tumor cells. The hydrodynamic diameter of diPTX@PSSP nanoparticles was 114.3 nm ± 2.1 (PDI = 0.219 ± 0.016), and the micelles had long-term colloidal stability and the drug-loading content (DLC) of diPTX and PTX is 16.7 and 46.9%, respectively. The prepared micelles could broke under the reductive microenvironment within tumor cells, as a result, the dimeric prodrug of diP and polymeric prodrug micelles of PSSP were rapidly disassembled, leading to the rapid release of intracellular drugs. In vitro release studies showed that under the condition of reduced glutathione (GSH) (10 mM), the release of PTX was significantly accelerated with approximately 86.6% released within 21 h, and the released PTX in cytoplasm could promote the disintegration of microtubules and induce cell apoptosis. These results indicated that the new type of this reduction-sensitive nanodrug delivery system based on dimeric prodrug@polymeric prodrug micelles would be a promising technology in chemotherapy.