Chloroquine-Modified Hydroxyethyl Starch as a Polymeric Drug for Cancer Therapy

Exploring starch-based excipients in pharmaceutical formulations: Versatile applications and future perspectives

Starch, a naturally abundant and biocompatible polysaccharide, serves as a key excipient in pharmaceutical formulations, enhancing drug stability, efficacy, and manufacturability. This review explores the properties, modifications, and diverse applications of starch-based excipients. Native starches from corn, potato, rice, and wheat are commonly used as disintegrants, binders, and fillers. Physical (e.g., pre-gelatinization), chemical (e.g., cross-linking, acetylation), and enzymatic modifications improve their functionality, such as enhanced stability and colon-specific drug delivery. Starch excels as a binder, improving tablet cohesion and strength, and as a disintegrant, promoting rapid drug release. It also supports controlled and sustained-release systems and advanced drug delivery methods, like nanoparticles and microparticles. Compared to other natural and synthetic excipients, starch offers advantages in biodegradability, non-toxicity, and cost-effectiveness, despite challenges like stability and batch variability. Innovations such as starch nanocrystals show promise in boosting drug solubility and bioavailability. Looking ahead, starch-based excipients hold potential for sustainable pharmaceutical development, personalized medicine, and 3D printing.

Suppression of hypoxia-induced CAV1 autophagic degradation enhances nanoalbumin-paclitaxel transcytosis and improves therapeutic activity in pancreatic cancer

Nanoalbumin-paclitaxel (nab-paclitaxel) is a standard chemotherapy for pancreatic cancer but has shown limited efficacy. However, the mechanism through which circulating nab-paclitaxel passes through the tumour vascular endothelium has not been determined. In our study, a new nonradioactive and highly sensitive method for analysing nab-paclitaxel transcytosis was established. Based on these methods, we found that hypoxia significantly enhanced the autophagic degradation of CAV1 and therefore attenuated caveolae-mediated nab-paclitaxel transcytosis across endothelial cells (ECs). In a proof-of-concept experiment, higher levels of CAV1, accompanied by lower levels of LC3B, were observed in the vascular endothelium of pancreatic cancer tissues collected from patients who showed a good response to nab-paclitaxel compared with those from patients who showed a poor response to nab-paclitaxel. Furthermore, both in vivo and in vitro studies confirmed that suppressing the autophagic degradation of CAV1 via EC-specific ATG5 knockdown or hydroxychloroquine sulfate (HCQ) treatment significantly enhanced nab-paclitaxel translocation across the endothelial barrier into pancreatic cancer cells and amplified the inhibitory effect of nab-paclitaxel on pancreatic tumour growth. The stimulation of CAV1 expression by EC-specific overexpression of exogenous CAV1 or administration of gemcitabine hydrochloride (GE) had the same effect. These results demonstrated that suppressing CAV1 autophagic degradation is a novel translatable strategy for enhancing nab-paclitaxel chemotherapeutic activity in the treatment of pancreatic cancer.

A review on advancements in the application of starch-based nanomaterials in biomedicine: Precision drug delivery and cancer therapy

The burgeoning field of starch-based nanomaterials in biomedical applications has perceived notable progressions, with a particular emphasis on their pivotal role in precision drug delivery and the inhibition of tumor growth. The complicated challenges in current biomedical research require innovative approaches for improved therapeutic outcomes, prompting an exploration into the possible of starch-based nanomaterials. The conceptualization of this review emerged from recognizing the need for a comprehensive examination of the structural attributes, versatile properties, and mechanisms underlying the efficiency of starch-based nanomaterials in inhibiting tumor growth and enabling targeted drug delivery. This review delineates the substantial growth in utilizing starch-based nanomaterials, elucidating their small size, high surface-volume ratio, and biocompatibility, predominantly emphasizing their possible to actively recognize cancer cells, deliver anticancer drugs, and combat tumors efficiently. The investigation of these nanomaterials encompasses to improving biocompatibility and targeting specific tissues, thereby contributing to the evolving landscape of precision medicine. The review accomplishes by highlighting the auspicious strategies and modern developments in the field, envisioning a future where starch-based nanomaterials play a transformative role in molecular nanomaterials, evolving biomedical sciences. The translation of these advancements into clinical applications holds the potential to revolutionize targeted drug delivery and expand therapeutic outcomes in the realm of precision medicine.

Hydroxychloroquine: Key therapeutic advances and emerging nanotechnological landscape for cancer mitigation

Hydroxychloroquine (HCQ) is a unique class of medications that has been widely utilized for the treatment of cancer. HCQ plays a dichotomous role by inhibiting autophagy induced by the tumor microenvironment (TME). Preclinical studies support the use of HCQ for anti-cancer therapy, especially in combination with conventional anti-cancer treatments since they sensitize tumor cells to drugs, potentiating the therapeutic activity. However, clinical evidence has suggested poor outcomes for HCQ due to various obstacles, including non-specific distribution, low aqueous solubility and low bioavailability at target sites, transport across tissue barriers, and retinal toxicity. These issues are addressable via the integration of HCQ with nanotechnology to produce HCQ-conjugated nanomedicines. This review aims to discuss the pharmacodynamic, pharmacokinetic and antitumor properties of HCQ. Furthermore, the antitumor performance of the nanoformulated HCQ is also reviewed thoroughly, aiming to serve as a guide for the HCQ-based enhanced treatment of cancers. The nanoencapsulation or nanoconjugation of HCQ with nanoassemblies appears to be a promising method for reducing the toxicity and improving the antitumor efficacy of HCQ.

Para-Methoxybenzylidene Acetal-Protected D-Glucosamine Derivatives as pH-Responsive Gelators and Their Applications for Drug Delivery

Carbohydrate-based low molecular weight gelators (LMWGs) are compounds with the capability to self-assemble into complex molecular networks within a solvent, leading to solvent immobilization. This process of gel formation depends on noncovalent interactions, including Van der Waals, hydrogen bonding, and π-π stacking. Due to their potential applications in environmental remediation, drug delivery, and tissue engineering, these molecules have emerged as an important area of research. In particular, various 4,6-O-benzylidene acetal-protected D-glucosamine derivatives have shown promising gelation abilities. In this study, a series of C-2-carbamate derivatives containing a para-methoxy benzylidene acetal functional group were synthesized and characterized. These compounds exhibited good gelation properties in several organic solvents and aqueous mixtures. Upon removal of the acetal functional group under acidic conditions, a number of deprotected free sugar derivatives were also synthesized. Analysis of these free sugar derivatives revealed two compounds were hydrogelators while their precursors did not form hydrogels. For those protected carbamates that are hydrogelators, removal of the 4,6-protection will result in a more water-soluble compound that produces a transition from gel to solution. Given the ability of these compounds to form gels from solution or solution from gels in situ in response to acidic environments, these compounds may have practical applications as stimuli-responsive gelators in an aqueous medium. In turn, one hydrogelator was studied for the encapsulation and release of naproxen and chloroquine. The hydrogel exhibited sustained drug release over a period of several days, with the release of chloroquine being faster at lower pH due to the acid lability of the gelator molecule. The synthesis, characterization, gelation properties, and studies on drug diffusion are discussed.

Novel amphiphilic hydroxyethyl starch-based nanoparticles loading camptothecin exhibit high anticancer activity in HepG2 cells and zebrafish

Camptothecin is a naturally occurred anticancer drug but exhibits limitations including poor aqueous solubility, low bioavailability, and high level of adverse drug reactions on normal organs. To overcome these problems, this paper developed a novel amphiphilic Lau-Leu-HES carrier using hydroxyethyl starch, lauric acid, and L-leucine as starting materials. The carrier was successfully applied to prepare Lau-Leu-HES nanoparticles loading camptothecin. The drug loading efficiency and encapsulation efficiency of the nanoparticles were calculated to be 29.04% and 81.85%, respectively. The nanoparticles exhibited high zeta potential (-15.51 mV) and small hydrodynamic diameter (105.4 nm). Camptothecin in nanoparticles could be rapidly released under acidic condition (pH = 4.5), thereby indicating the high sensitivity under cancer microenvironments. Anticancer investigation revealed that the nanoparticles could inhibit the proliferation of HepG2 cells in vitro. Compared with commercial available drug doxorubicin, the nanoparticles could significantly inhibit the expression of kras^v12 oncogene in transgenic Tg (EGFP-kras^V12) zebrafish. These results indicate that the camptothecin-loaded Lau-Leu-HES nanoparticles are expected to be a potential candidate for cancer therapy.

Recent advances in pH/enzyme-responsive polysaccharide-small-molecule drug conjugates as nanotherapeutics

Now-a-days, the polysaccharides are extensively employed for the delivery of small-molecule drugs ascribed to their excellent biocompatibility, biodegradability and modifiability. An array of drug molecules is often chemically conjugated with different polysaccharides to augment their bio-performances. As compared to their therapeutic precursors, these conjugates could typically demonstrate an improved intrinsic solubility, stability, bioavailability and pharmacokinetic profiles of the drugs. In current years, various stimuli-responsive particularly pH and enzyme-sensitive linkers or pendants are also exploited to integrate the drug molecules into the polysaccharide backbone. The resulting conjugates could experience a rapid molecular conformational change upon exposure to the microenvironmental pH and enzyme changes of the diseased states, triggering the release of the bioactive cargos at the targeted sites and eventually minimize the systemic side effects. Herein, the recent advances in pH and enzyme -responsive polysaccharide-drug conjugates and their therapeutic benefits are systematically reviewed, following a brief description on the conjugation chemistry of the polysaccharides and drug molecules. The challenges and future perspectives of these conjugates are also precisely discussed.

Enhanced Sensitivity of Tumor Cells to Autophagy Inhibitors Using Fasting-Mimicking Diet and Targeted Lysosomal Delivery Nanoplatform

Autophagy is one of the key pathways for tumor cell survival and proliferation. Therefore, inhibition of autophagy has been extensively studied for cancer therapy. However, current autophagy inhibitors lack specificity and are ineffective in limiting tumor progression. Herein, we report a nanoplatform for tumor-site-targeted delivery of hydroxychloroquine (HCQ) using insulin-like growth factors 2 receptor (IGF2R)-targeted liposomes (iLipo-H). A fasting-mimicking diet (FMD) is used to increase the autophagy levels in tumor cells, thereby increasing the sensitivity of tumor cells to HCQ. In addition, FMD treatment upregulates the expression of IGF2R in tumor cells, but not normal cells. Consequently, iLipo-H nanoparticles efficiently accumulate at the tumor site under FMD condition. In vivo studies demonstrate that iLipo-H nanoparticles efficiently inhibit 4T1 tumor growth without obvious side effects, especially under FMD condition. This study provides a promising strategy to increase the sensitivity of tumor cells to autophagy inhibitors for effective cancer therapy.

Fabrication of a magnetic nanocarrier for doxorubicin delivery based on hyperbranched polyglycerol and carboxymethyl cellulose: An investigation on the effect of borax cross-linker on pH-sensitivity

A new core-shell pH-responsive nanocarrier was prepared based on magnetic nanoparticle (MNP) core. Magnetic nanoparticles were first modified with hyperbranched polyglycerol as the first shell. Then the magnetic core was decorated with doxorubicin anticancer drug (DOX) and covered with PEGylated carboxymethylcellulose as the second shell. Borax was used to partially cross-link organic shells in order to evaluate drug loading content and pH-sensitivity. The structure of nanocarrier, organic shell loadings, magnetic responsibility, morphology, size, dispersibility, and drug loading content were investigated by IR, NMR, TG, VSM, XRD, DLS, HR-TEM and UV-Vis analyses. In vitro release investigations demonstrated that the use of borax as cross-linker between organic shells make the nanocarrier highly sensitive to pH so that more that 70% of DOX is released in acidic pH. A reverse pH-sensitivity was observed for the nanocarrier without borax cross-linker. The MTT assay determined that the nanocarrier exhibited excellent biocompatibility toward normal cells (HEK-293) and high toxicity against cancerous cells (HeLa). The nanocarrier also showed high hemocompatibility. Cellular uptake revealed high ability of nanocarrier toward HeLa cells comparable with free DOX. The results also suggested that low concentration of nanocarrier has a great potential for use as contrast agent in magnetic resonance imaging (MRI).

A Review of Modifications of Quinoline Antimalarials: Mefloquine and (hydroxy)Chloroquine

Late-stage modification of drug molecules is a fast method to introduce diversity into the already biologically active scaffold. A notable number of analogs of mefloquine, chloroquine, and hydroxychloroquine have been synthesized, starting from the readily available active pharmaceutical ingredient (API). In the current review, all the modifications sites and reactivity types are summarized and provide insight into the chemistry of these molecules. The approaches include the introduction of simple groups and functionalities. Coupling to other drugs, polymers, or carriers afforded hybrid compounds or conjugates with either easily hydrolyzable or more chemically inert bonds. The utility of some of the compounds was tested in antiprotozoal, antibacterial, and antiproliferative assays, as well as in enantiodifferentiation experiments.

Magnetic graphene oxide-lignin nanobiocomposite: a novel, eco-friendly and stable nanostructure suitable for hyperthermia in cancer therapy

In this research, a novel magnetic nanobiocomposite was designed and synthesized in a mild condition, and its potential in an alternating magnetic field was evaluated for hyperthermia applications. For this purpose, in the first step, graphene oxide was functionalized with a natural lignin polymer using epichlorohydrin as the cross-linking agent. In the second step, the designed magnetic graphene oxide-lignin nanobiocomposite was fabricated by the in situ preparation of magnetic Fe3O4 nanoparticles in the presence of graphene oxide functionalized with lignin. The resultant magnetic nanobiocomposite possessed certain main properties, including stability and homogeneity in aqueous solutions, making it suitable for hyperthermia applications. The chemical and structural properties of the synthesized magnetic graphene oxide-lignin composite were characterized using FT-IR, EDX, FE-SEM, TEM, TG and VSM analyses. The saturation magnetization value of this magnetic nanocomposite was recorded as 17.2 emu g-1. Further, the maximum specific absorption rate was determined to be 121.22 W g-1. Given these results, this newly fabricated magnetic nanobiocomposite may achieve considerable performance under the alternating magnetic field in fluid hyperthermia therapy.

Smart drug delivery of p-Coumaric acid loaded aptamer conjugated starch nanoparticles for effective triple-negative breast cancer therapy

The nano-drug delivery system utilizing the ligand functionalized nanoparticles have a tremendous application in cancer therapeutics. The present study was aimed to fabricate the p-Coumaric acid-loaded aptamer (ligand) conjugated starch nanoparticles (Apt-p-CA-AStNPs) for effective treatment of triple-negative breast cancer (MDA-MB-231). The FT-IR spectrum showed the presence of functional groups associated with para-Coumaric acid (p-CA) and amino starch (AS) in p-CA-AStNPs. Further, the conjugation of aptamer in p-CA-AStNPs was confirmed by agarose gel electrophoresis. Transmission electron microscopic analysis revealed that the synthesized Apt-p-CA-AStNPs were less agglomerated. The zeta size analyzer displayed the average particle size of 218.97 ± 3.07 nm with ȥ-potential -29.2 ± 1.35 mV, and PDI 0.299 ± 0.05 for Apt-p-CA-AStNPs. The drug encapsulation and loading efficiencies were 80.30 ± 0.53% and 10.35 ± 0.85% respectively for Apt-p-CA-AStNPs. Apt-p-CA-AStNPs showed a rapid and bursting release in the initial five hours of the experiment in pH 5.4. A significant change was found in their cytotoxic efficacy between the samples: p-CA, p-CA-AStNPs, and Apt-p-CA-AStNPs. Among the tested samples, Apt-p-CA-AStNPs caused higher cytotoxicity in MDA-MB-231 cells through ROS regulation, nuclear damage, mitochondrial membrane potential, and apoptosis-related protein expressions. Overall, these results proved that Apt-p-CA-AStNPs were efficiently inhibited the MDA-MB-231 cells by regulating apoptosis.

"Attractive/adhesion force" dual-regulatory nanogels capable of CXCR4 antagonism and autophagy inhibition for the treatment of metastatic breast cancer

Metastasis is refractory systemic disease resulting in low survival rate of breast cancer patients, especially in the late stage. The processes of metastasis are mainly initiated by strong "attractive force" from distant organs and deteriorated by weak "adhesion force" in primary tumor. Here, we reported "attractive/adhesion force" dual-regulatory nanogels (CQ-HF/PTX) for the precise treatment of both primary and metastasis of metastatic breast cancer. Hydroxychloroquine (HCQ) and hydrophobic Fmoc were grafted on hydrophilic hydroxyethyl starch (HES) to obtain amphiphilic CQ-HF polymer, which was assembly with chemotherapy drug paclitaxel (PTX) to form the nanogels for anti-primary tumor. Meanwhile, CQ-HF/PTX nanogels play two roles in anti-metastasis: i) For reducing the "attractive force", it could block the CXCR4/SDF-1 pathway, preventing tumor cells metastasis to the lung; ii) For reinforcing "adhesion force", it could inhibit the excessive autophagy for hindering the degradation of paxillin and enhancing the cell adhesion. As a result, dual-regulatory CQ-HF/PTX nanogels dramatically inhibited tumor and the lung metastasis of mouse breast cancer. Therefore, the fabricating of synergetic dual-regulatory nanogels uncovered the explicit mechanism and provided an efficient strategy for combating malignant metastatic tumors.

Multifunctional applications of natural polysaccharide starch and cellulose: An update on recent advances

The emergence of clinical complications and therapeutic challenges for treating various diseases necessitate the discovery of novel restorative functional materials. Polymer-based drug delivery systems have been extensively reported in the last two decades. Recently, there has been an increasing interest in the progression of natural biopolymers based controlled therapeutic strategies, especially in drug delivery and tissue engineering applications. However, the solubility and functionalisation due to their complex network structure and intramolecular bonding seem challenging. This review explores the current advancement and prospects of the most promising natural polymers such as cellulose, starch and their derivatives-based drug delivery vehicles like hydrogels, films and composites, in combating major ailments such as bone infections, microbial infections, and cancers. In addition, selective drug targeting using metal-drug (MD) and MD-based polymeric missiles have been exciting but challenging for its application in cancer therapeutics. Owing to high biocompatibility of starch and cellulose, these materials have been extensively evaluated in biomedical and pharmaceutical applications. This review presents a detailed impression of the current trends for the construction of biopolymer-based tissue engineering, drug/gene/protein delivery vehicles.

Regulation and function of autophagy in pancreatic cancer

Oncogenic KRAS mutation-driven pancreatic ductal adenocarcinoma is currently the fourth-leading cause of cancer-related deaths in the United States. Macroautophagy (hereafter "autophagy") is one of the lysosome-dependent degradation systems that can remove abnormal proteins, damaged organelles, or invading pathogens by activating dynamic membrane structures (e.g., phagophores, autophagosomes, and autolysosomes). Impaired autophagy (including excessive activation and defects) is a pathological feature of human diseases, including pancreatic cancer. However, dysfunctional autophagy has many types and plays a complex role in pancreatic tumor biology, depending on various factors, such as tumor stage, microenvironment, immunometabolic state, and death signals. As a modulator connecting various cellular events, pharmacological targeting of nonselective autophagy may lead to both good and bad therapeutic effects. In contrast, targeting selective autophagy could reduce potential side effects of the drugs used. In this review, we describe the advances and challenges of autophagy in the development and therapy of pancreatic cancer.Abbreviations: AMPK: AMP-activated protein kinase; CQ: chloroquine; csc: cancer stem cells; DAMP: danger/damage-associated molecular pattern; EMT: epithelial-mesenchymal transition; lncRNA: long noncoding RNA; MIR: microRNA; PanIN: pancreatic intraepithelial neoplasia; PDAC: pancreatic ductal adenocarcinoma; PtdIns3K: phosphatidylinositol 3-kinase; SNARE: soluble NSF attachment protein receptor; UPS: ubiquitin-proteasome system.

Unveiling the Molecular Structure of Antimalarial Drugs Chloroquine and Hydroxychloroquine in Solution through Analysis of 1H NMR Chemical Shifts

Chloroquine (CQ) and hydroxychloroquine (HCQ) have been standard antimalarial drugs since the early 1950s, and very recently, the possibility of their use for the treatment of COVID-19 patients has been considered. To understand the drug mode of action at the submicroscopic level (atoms and molecules), molecular modeling studies with the aid of computational chemistry methods have been of great help. A fundamental step in such theoretical investigations is the knowledge of the predominant drug molecular structure in solution, which is the real environment for the interaction with biological targets. Our strategy to access this valuable information is to perform density functional theory (DFT) calculations of ¹H NMR chemical shifts for several plausible molecular conformers and then find the best match with experimental NMR profile in solution (since it is extremely sensitive to conformational changes). Through this procedure, after optimizing 30 trial distinct molecular structures (ωB97x-D/6-31G(d,p)-PCM level of calculation), which may be considered representative conformations, we concluded that the global minimum (named M24), stabilized by an intramolecular N-H hydrogen bond, is not likely to be observed in water, chloroform, and dimethyl sulfoxide (DMSO) solution. Among fully optimized conformations (named M1 to M30, and MD1 and MD2), we found M12 (having no intramolecular H-bond) as the most probable structure of CQ and HCQ in water solution, which is a good approximate starting geometry in drug-receptor interaction simulations. On the other hand, the preferred CQ and HCQ structure in chloroform (and CQ in DMSO-d₆) solution was assigned as M8, showing the solvent effects on conformational preferences. We believe that the analysis of ¹H NMR data in solution can establish the connection between the macro level (experimental) and the sub-micro level (theoretical), which is not so apparent to us and appears to be more appropriate than the thermodynamic stability criterion in conformational analysis studies.

Polymer-Drug Conjugates as Nanotheranostic Agents

Since the last decade, the polymer-drug conjugate (PDC) approach has emerged as one of the most promising drug-delivery technologies owing to several benefits like circumventing premature drug release, offering controlled and targeted drug delivery, improving the stability, safety, and kinetics of conjugated drugs, and so forth. In recent years, PDC technology has advanced with the objective to further enhance the treatment outcomes by integrating nanotechnology and multifunctional characteristics into these systems. One such development is the ability of PDCs to act as theranostic agents, permitting simultaneous diagnosis and treatment options. Theranostic nanocarriers offer the opportunity to track the distribution of PDCs within the body and help to localize the diseased site. This characteristic is of particular interest, especially among those therapeutic approaches where external stimuli are supposed to be applied for abrupt drug release at the target site for localized delivery to avoid systemic side effects (e.g., Visudyne®). Thus, with the help of this review article, we are presenting the most recent updates in the domain of PDCs as nanotheranostic agents. Different methodologies utilized to design PDCs along with imaging characteristics and their applicability in a wide range of diseases, have been summarized in this article.

Topological Study of Hydroxychloroquine Conjugated Molecular Structure Used for Novel Coronavirus (COVID-19) Treatment

The novel coronavirus disease 2019 (Covid-19) is a mutating and recombining pandemic that potentially spreading through an infected person in droplet-generated forms that have affected more than 200 countries and endanger the entire globe. There is no clear strategy for the care of COVID-19 cases. Moreover, experts across the globe are working actively to develop medicinal or anti-virus drugs. On the basis of recent clinical findings and recommendations, the study examined a variety of new medications that have shown antiviral activity against SARS-CoV-2, among other drugs, antimalarial medications Chloroquine (CQ) and Hydroxychloroquine (HCQ) have gained significant publicity to have promising effects against SARS-CoV-2. Linking a bioactive substance to a biocompatible polymer typically provides various concerns, such as improved drug solubilization, improved modification, precise restriction, and controlled discharge. An enormous number of medical analyses have confirmed that the characteristics of medical drugs have a nearby connection with their atomic structure. Medication properties can be acquired by considering the atomic structure of relating drugs. The calculation of the topological index of a medication structure empowers researchers to have a superior comprehension of the physical science and bio-organic attributes of drugs. Ev-degree and ve-degree based topological indices are two novel degrees based indices as of late defined in graph theory. Ev-degree and ve-degree based topological indices have been defined as corresponding to their relating partners. In this paper, we have computed topological indices based on ev-degree and ve-degree for the Hydroxyethyl Starch and Hydroxychloroquine (HCQ-HEC) bioconjugate molecular structure.

Hydroxyethyl starch and its derivatives as nanocarriers for delivery of diagnostic and therapeutic agents towards cancers

Many types of drugs and agents used for cancer diagnosis and therapy often have low bioavailability and insufficient efficacy, as well as causing various side effects due to their nonspecific delivery. Nanocarriers with purposely-designed compositions and structures have shown varying degrees of abilities to deliver these compounds towards cancers in passive or active manners. Despite the availability of a variety of materials for the construction of nanocarriers, natural polymers with good biocompatibility and biodegradability are preferable for such usage because of their high in vivo safety as well as easy removal of degradation products. Among the natural polymers intended for building nanocarriers, hydroxyethyl starch and its derivatives have gained tremendous attention in the field of drug delivery in the form of nanomedicines over the last decade. There is growing optimism that ever more hydroxyethyl starch-based nanomedicines will be a significant addition to the armoury currently used for cancer diagnosis and therapy.

Inhibition of Cathepsin D (CTSD) enhances radiosensitivity of glioblastoma cells by attenuating autophagy

Postoperative radiotherapy combined with chemotherapy is a commonly used treatment for glioblastoma (GBM) but radiotherapy often fails to achieve the expected results mainly due to tumor radioresistance. In this study, we established a radioresistant subline from human glioma cell line U251 and found that Cathepsin D (CTSD), a gene closely related to the clinical malignancy and prognosis in glioma, had higher expression level in radioresistant clones than that in parental cells, and knocking down CTSD by small interfering RNA (siRNA) or its inhibitor Pepstatin-A increased the radiosensitivity. The level of autophagy was enhanced in the radioresistant GBM cells compared with its parent cells, and silencing autophagy by light chain 3 (LC3) siRNA significantly sensitized GBM cells to ionizing radiation (IR). Moreover, the protein expression level of CTSD was positively correlated with the autophagy marker LC3 II/I and negatively correlated with P62 after IR in radioresistant cells. As expected, through the combination of Western blot and immunofluorescence assays, inhibition of CTSD increased the formation of autophagosomes, while decreased the formation of autolysosomes, which indicating an attenuated autophagy level, leading to radiosensitization ultimately. Our results revealed for the first time that CTSD regulated the radiosensitivity of glioblastoma by affecting the fusion of autophagosomes and lysosomes. In significance, CTSD might be a potential molecular biomarker and a new therapeutic target in glioblastoma.

In Situ Autophagy Disruption Generator for Cancer Theranostics

Cancer remains a serious clinical disease awaiting new effective treatment strategies. Autophagy modulation has emerged as a novel and promising pharmacologic target critical to future drug development and anti-cancer therapy applications. Herein, we constructed an in situ autophagy disruption generator to break the balance of autophagy flow for tumor-targeting therapy. Hollow mesoporous manganese trioxide (Mn₂O₃) nanoparticles (NPs) were synthesized and conjugated with hyaluronic acid (HA) to form tumor-targeting drug carriers. Then, traditional autophagy inhibitor hydroxychloroquine (HCQ) was loaded into the hollow core of HA-Mn₂O₃, to form a multifunctional theranostics platform (HA-Mn₂O₃/HCQ). This nanoplatform displayed specific localization and retention in lysosomes after entering tumor cells. The synchronous release of HCQ and manganese ion (Mn²⁺) induced lysosomal alkalization and osmotic pressure elevation. Significantly greater lysosomal deacidification and autophagy blockade effect emerged after treatment by this nanoplatform, with in vitro tumor inhibition rate of 92.2%. Imaging experiment proved that it could selectively deliver HCQ to tumor sites and further degrade to realize simultaneous release of Mn²⁺ and HCQ. Micromorphological and immunofluorescence analysis demonstrated that in situ high concentrations of these two substances would achieve effective autophagy blockade. Pharmacodynamics test showed that this nanogenerator displayed the best therapeutic efficacy with 5.08-fold tumor inhibition ratio compared with the HCQ group. Moreover, the generated Mn²⁺ can be used as T1 contrast agent for visualizing tumor lesions and monitoring therapeutic effects. Overall, the as-made multifunctional drug-delivery system might provide a promising platform for cancer theranostics upon in situ autophagy disruption.

Transformable nanotherapeutics enabled by ICG: towards enhanced tumor penetration under NIR light irradiation

Tumor penetration is the bottleneck for current cancer nanomedicine, limiting the ultimate antitumor efficacy in the clinic. Herein, by exploiting the well-known instability of indocyanine green (ICG), we report the preparation of near infrared (NIR) light responsive nanoparticles (NP) for enhanced tumor penetration. ICG crosslinks hydroxyethyl starch (HES) and doxorubicin (DOX) conjugates (HES-SS-DOX) via noncovalent interactions, facilitating the formation of ICG@HES-SS-DOX NP. The light triggered degradation of ICG leads to the dissociation of such NP, and the resulting HES-SS-DOX has been shown to penetrate deeper in both H22 tumor spheroids and tumor bearing mice, due to the photothermal effect of ICG. Therefore, the disintegrable ICG@HES-SS-DOX NP have better tumor penetration capacity than their counterparts, which originally cannot dissociate under NIR light stimulation. The reported ICG@HES-SS-DOX NP might be potent in treating malignant tumors with dense extracellular matrices, such as liver and pancreatic cancers. This study opens up a novel functionality of FDA-approved ICG for cancer nanotherapeutics.

Colloidal hydroxyethyl starch for tumor-targeted platinum delivery

Cis-platinum has been widely used as a first-line chemotherapy agent in clinics for more than 40 years. Although considerable efforts have been expended for developing platinum-based nano drug delivery systems (NDDS) to resolve the problems of low water solubility, short half-life, and severe side effects of cis-platinum, it remains challenging to apply these nanoplatforms to cancer treatments in clinics on account of the issues related to safety, complex fabrication procedures, and limited cellular uptake. Herein, we constructed a novel cis-platinum delivery system with hydroxyethyl starch (HES), which is a semisynthetic polysaccharide that has been used worldwide as colloidal plasma volume expanders (PVE) in clinics for several decades. By combining TEM, AFM, and DLS, we have found that HES particles are colloidal nanoparticles in solution, with diameters ranging from 15 to 40 nm as a function of molecular weight. We further revealed that HES adopted a hyperbranched colloidal structure with rather compact conformation. These results demonstrate that HES is a promising nanocarrier to deliver drug molecules. Taking advantage of the poly-hydroxyl sites of HES, we constructed a novel HES-based cis-platinum delivery nanoplatform. HES was directly conjugated with cis-platinum prodrug via an ester bond and decorated with an active targeting molecule, lactobionic acid (LA), contributing toward higher in vitro antitumor activity against hepatoma carcinoma cells as compared to cis-platinum. These results have significant implications for the clinically used plasma volume expander-HES and shed light on the clinical translation of HES-based nano drug delivery systems.

Autophagy therapeutics: preclinical basis and initial clinical studies

Autophagy captures and degrades intracellular components such as proteins and organelles to sustain metabolism and homeostasis. Rapidly accumulating attention is being paid to the role of autophagy in the development of cancer, which makes autophagy attractive tools and targets for novel therapeutic approaches. Functional studies have confirmed that autophagy dysregulation is causal in many cases of cancer, with autophagy acting as tumor suppressors or tumor promoters, and autophagy inhibitor or promoter has shown promise in preclinical studies. The autophagy-targeted therapeutics using chloroquine/hydroxychloroquine have reached clinical development for treating cancer, but these drugs are actually not efficient probably because of a reduced penetration within the tumor. In this review, we first discuss the discoveries related to dual function of autophagy in cancer. Then, we provide an overview of preclinical studies and clinical trials involved in the development of autophagy therapeutics and finally discuss the future of such therapies.

Promise of chemokine network-targeted nanoparticles in combination nucleic acid therapies of metastatic cancer

Chemokines and chemokine receptors play key roles in cancer progression and metastasis. Although multiple chemokines and chemokine receptors have been investigated, inhibition of CXCR4 emerged as one of the most promising approaches in combination cancer therapy, especially when focused on the metastatic disease. Small RNA molecules, such as small interfering RNA (siRNA) and microRNA (miRNA), represent new class of therapeutics for cancer treatment through RNA interference-mediated gene silencing. However, the clinical applicability of siRNA and miRNA is severely limited by the lack of effective delivery systems. There is a significant therapeutic potential for CXCR4-targeted nanomedicines in combination with the delivery of siRNA and miRNA in cancer. Recently developed CXCR4-targeted polymeric drugs and nanomedicines, including cyclam- and chloroquine-based polymeric CXCR4 antagonists are introduced here and their ability to deliver functional siRNA and miRNA is discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

High-yielding continuous-flow synthesis of antimalarial drug hydroxychloroquine

Numerous synthetic methods for the continuous preparation of fine chemicals and active pharmaceutical ingredients (API’s) have been reported in recent years resulting in a dramatic improvement in process efficiencies. Herein we report a highly efficient continuous synthesis of the antimalarial drug hydroxychloroquine (HCQ). Key improvements in the new process include the elimination of protecting groups with an overall yield improvement of 52% over the current commercial process. The continuous process employs a combination of packed bed reactors with continuous stirred tank reactors for the direct conversion of the starting materials to the product. This high-yielding, multigram-scale continuous synthesis provides an opportunity to achieve increase global access to hydroxychloroquine for treatment of malaria.