Preclinical and clinical studies of NK012, an SN-38-incorporating polymeric micelles, which is designed based on EPR effect

High-load nanoparticles with a chemotherapeutic SN-38/FdUMP drug cocktail

[Gd(OH)]2+[(SN-38)0.5(FdUMP)0.5]2- inorganic-organic hybrid nanoparticles (IOH-NPs) with a chemotherapeutic cocktail of ethyl-10-hydroxycamptothecin (SN-38, active form of irinotecan) and 5-fluoro-2'-deoxyuridine-5'-phosphate (FdUMP, active form of 5'-fluoruracil), 40 nm in size, are prepared in water. The IOH-NPs contain a total drug load of 63 wt% with 33 wt% of SN-38 and 30 wt% of FdUMP. Cell-based assays show efficient cellular uptake and promising anti-tumour activity on two pancreatic cancer cell lines of murine origin (KPC, Panc02). Beside the high-load drug cocktail, especially the option to use SN-38, which - although 100- to 1000-times more potent than irinotecan - is usually unsuitable for systemic administration due to poor solubility, low stability, and high toxicity upon non-selective delivery. The [Gd(OH)]2+[(SN-38)0.5(FdUMP)0.5]2- IOH-NPs are a new concept to deliver a drug cocktail with SN-38 and FdUMP directly to the tumour, shielded in a nanoparticle, to reduce side effects.

Position Matters: Pyridine Regioisomers Influence Secondary Structure and Micelle Morphology in Polymer-Homopolypeptide Micelles

Polymer-homopolypeptide block copolymers are a class of bioinspired materials that combine the processability and stability of synthetic polymers with the biocompatibility and unique secondary structures of peptides, such as α-helices and β-sheets. These properties make them ideal candidates for a wide variety of applications, for example, in the pharmaceutical field, where they are frequently explored as building blocks for polymeric micelle drug delivery systems. While homopolypeptide side chains can be furnished with an array of different moieties to impart the copolymers with desirable properties, such as stimulus responsivity, pyridine derivatives represent an underutilized functional group for this purpose. Additionally, the interplay between polypeptide side chain structure, secondary conformation, and micelle morphology is not yet well understood, particularly in the case of structural regioisomers. Therefore, in this work, a series of polymer-homopolypeptide copolymers were prepared from a poly(ethylene glycol)-b-poly(glutamic acid) (PEG-b-PGA) backbone, where the pendant carboxylic acid groups were covalently conjugated to a series of pyridine regioisomers by carbodiimide coupling. These pyridine regioisomers differed only in the position of the nitrogen heteroatom, ortho, meta or para, relative to the linking group, generating a series of PEG-b-poly(pyridinylmethyl glutamate) (PEG-b-PMG) copolymers. Following self-assembly of the copolymers in aqueous solutions, dynamic light scattering (DLS) revealed differences in micelle hydrodynamic diameter (Dh) (ranging from ∼60 to 120 nm), while transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) revealed distinctive morphologies ranging from ellipsoidal, to cylindrical, and disc-like, suggesting that subtle changes in positional isomers in the polypeptide block may influence the micelle structure. Analysis of the PEG-b-PMG copolymer micelles by circular dichroism (CD) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy revealed that differences in the morphology were associated with changes in polypeptide secondary structure, which in turn was influenced by the position of the pyridine heteroatom. Overall, these findings contribute to the broader understanding of the relationship between polypeptide structure and micelle morphology and serve as useful insight for the rational design of polymer-polypeptide nanoparticles.

Ultrasmall Carbon Nanodots as Theranostic Nanoheaters for Precision Breast Cancer Phototherapy: Establishing the Translational Potential in Tumor-in-a-Dish Models

This study investigates the remarkable attributes of sulfur-doped carbon nanodots (CDs) synthesized in high yield and a narrow size distribution (4.8 nm). These CDs exhibit notable features, including potential bioelimination through renal clearance and efficient photothermal conversion in the near-infrared region with multicolor photoluminescence across the visible spectrum. Our research demonstrates high biocompatibility and effective near-infrared (NIR)-triggered photothermal toxicity when targeting mammospheres and patient-derived tumor organoids. Moreover, the study delves into the intricate cellular responses induced by CD-mediated hyperthermia. This involves efficient tumor mass death, activation of the p38-mitogen-activated protein kinase (MAPK) pathway, and upregulation of genes associated with apoptosis, hypoxia, and autophagy. The interaction of CDs with mammospheres reveals their ability to penetrate the complex microenvironment, impeded at 4 °C, indicating an energy-dependent endocytosis mechanism. This observation underscores the CDs' potential for targeted drug delivery, particularly in anticancer therapeutics. This investigation contributes to understanding the multifunctional properties of sulfur-doped CDs and highlights their promising applications in cancer therapeutics. Utilizing 3-D tumor-in-a-dish patients' organoids enhances translational potential, providing a clinically relevant platform for assessing therapeutic efficacy in a context mirroring the physiological conditions of cancerous tissues.

Theranostic nanoparticles for detection and treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most recalcitrant cancers due to its late diagnosis, poor therapeutic response, and highly heterogeneous microenvironment. Nanotechnology has the potential to overcome some of the challenges to improve diagnostics and tumor-specific drug delivery but they have not been plausibly viable in clinical settings. The review focuses on active targeting strategies to enhance pancreatic tumor-specific uptake for nanoparticles. Additionally, this review highlights using actively targeted liposomes, micelles, gold nanoparticles, silica nanoparticles, and iron oxide nanoparticles to improve pancreatic tumor targeting. Active targeting of nanoparticles toward either differentially expressed receptors or PDAC tumor microenvironment (TME) using peptides, antibodies, small molecules, polysaccharides, and hormones has been presented. We focus on microenvironment-based hallmarks of PDAC and the potential for actively targeted nanoparticles to overcome the challenges presented in PDAC. It describes the use of nanoparticles as contrast agents for improved diagnosis and the delivery of chemotherapeutic agents that target various aspects within the TME of PDAC. Additionally, we review emerging nano-contrast agents detected using imaging-based technologies and the role of nanoparticles in energy-based treatments of PDAC. This article is categorized under: Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

A Guanosine-Derived Antitumor Supramolecular Prodrug

The prodrug strategy for its potential to enhance the pharmacokinetic and/or pharmacodynamic properties of drugs, especially chemotherapeutic agents, has been widely recognized as an important means to improve therapeutic efficiency. Irinotecan's active metabolite, 7-ethyl-10-hydroxycamptothecin (SN38), a borate derivative, was incorporated into a G-quadruplex hydrogel (GB-SN38) by the ingenious and simple approach. Drug release does not depend on carboxylesterase, thus bypassing the side effects caused by ineffective activation, but specifically responds to the ROS-overexpressed tumor microenvironment by oxidative hydrolysis of borate ester that reduces serious systemic toxicity from nonspecific biodistribution of SN38. Comprehensive spectroscopy was used to define the structural and physicochemical characteristics of the drug-loaded hydrogel. The GB-SN38 hydrogel's high level of biosafety and notable tumor-suppressive properties were proven in in vitro and in vivo tests.

Paclitaxel prodrug-encapsulated polypeptide micelles with redox/pH dual responsiveness for cancer chemotherapy

Polypeptides are a highly promising carrier for delivering hydrophobic drugs, due to their excellent biocompatibility, non-toxicity, and non-immunogenicity. Herein, a redox and pH dual-responsive poly(ethylene glycol)-SS-b-polypeptide micelles encapsulated with disulfide bridged paclitaxel-pentadecanoic acid prodrug was developed for cancer chemotherapy. First of all, disulfide bridged paclitaxel-pentadecanoic acid prodrug (PTX-SS-COOH) and poly(ethylene glycol)-SS-b-polylysine-b-polyphenylalanine (mPEG-SS-b-PLys-b-PPhe, ESLP) were synthesized and confirmed via NMR, MS, FT-IR or GPC. After that, PTX-SS-COOH (PSH) embedded mPEG-SS-b-PLys-b-PPhe (ESLP/PSH) micelles were prepared by mixing method based on electrostatic interactions and hydrophobic forces. For comparison, mPEG-b-PLys-b-PPhe (ELP) was mixed with PTX-SS-COOH to generate another kind of micelles (ELP/PSH). The characterization of ESLP/PSH micelles through dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed a spherical structure with a diameter of approximately 170 nm. It is noteworthy that ESLP/PSH micelles displayed a high drug-loading rate of 22.84%, and excellent stability, which can be attributed to the specific interactions between the prodrug and copolymer. Drug release analysis demonstrated that the micelles exhibited a substantial release of PTX in the presence of GSH at pH 5.0, indicating a pH and redox dual responsiveness. In vivo pharmacokinetic study revealed the ESLP/PSH micelles had increased bioavailability and an extended circulation time. Ultimately, antitumor efficacy and systemic toxicity evaluation in 4 T1 tumor-bearing mice confirmed that ESLP/PSH micelles achieved the highest level of tumor growth inhibition (ca. 83%) and the lowest systemic toxicity in comparison with ELP/PSH micelles and commercialized Taxol®. Taken together, the dual responsive micelles represent a promising PTX formulation with potential clinical application in cancer chemotherapy.

A Systematic Review of Clinical Trials on the Efficacy and Safety of CRLX101 Cyclodextrin-Based Nanomedicine for Cancer Treatment

CRLX101 is a cyclodextrin-based nanopharmaceutical designed to improve the delivery and efficacy of the anti-cancer drug camptothecin. Cyclodextrins have unique properties that can enhance drug solubility, stability, and bioavailability, making them an attractive option for drug delivery. The use of cyclodextrin-based nanoparticles can potentially reduce toxicity and increase the therapeutic index compared to conventional chemotherapy. CRLX101 has shown promise in preclinical studies, demonstrating enhanced tumor targeting and prolonged drug release. This systematic review followed PRISMA guidelines, assessing the efficacy and toxicity of CRLX101 in cancer treatment using clinical trials. Studies from January 2010 to April 2023 were searched in PubMed, Scopus, Web of Science, and Cochrane Database of Systematic Reviews, using specific search terms. The risk of bias was assessed using ROBINS-I and Cochrane risk-of-bias tools. After screening 6018 articles, 9 were included in the final review. These studies, conducted between 2013 and 2022, focused on patients with advanced or metastatic cancer resistant to standard therapies. CRLX101 was often combined with other therapeutic agents, resulting in improvements such as increased progression-free survival and clinical benefit rates. Toxicity was generally manageable, with common adverse events including fatigue, nausea, and anemia.

Polymeric core-crosslinked particles prepared via a nanoemulsion-mediated process: from particle design and structural characterization to in vivo behavior in chemotherapy

Various polymeric nanoparticles have been used as drug carriers in drug delivery systems (DDSs). Most of them were constructed from dynamic self-assembly systems formed via hydrophobic interactions and from structures that are unstable in an in vivo environment owing to their relatively weak formation forces. As a solution to this issue, physically stabilized core-crosslinked particles (CP) with chemically crosslinked cores have received attention as alternatives to the dynamic nanoparticles. This focused review summarizes recent advances in the construction, structural characterization, and in vivo behavior of polymeric CPs. First, we introduce a nanoemulsion-mediated method to create polyethylene glycol (PEG)-bearing CPs and their structural characterization. The relationship between the PEG chain conformations in the particle shell and the in vivo fate of the CPs is also discussed. After that, the development and advantages of zwitterionic amino acid-based polymer (ZAP)-bearing CPs are presented to address the poor penetration and the internalization of PEG-based CPs into tumor tissues and cells, respectively. Finally, we conclude and discuss prospects for application of polymeric CPs in the DDS field.

Recent advances in SN-38 drug delivery system

DNA topoisomerase I plays a key role in lubricatingthe wheels of DNA replication or RNA transcription through breaking and reconnecting DNA single-strand. It is widely known that camptothecin and its derivatives (CPTs) have inhibitory effects on topoisomerases I, and have obtained some clinical benefits in cancer treatment. The potent cytotoxicity makes 7-ethyl-10-hydroxycamptothecin (SN-38) become a brilliant star among these derivatives. However, some undesirable physical and chemical properties of this compound, including poor solubility and stability, seriously hinder its effective delivery to tumor sites. In recent years, strategies to alleviate these defects have aroused extensive research interest. By focusing on the loading mechanism, basic nanodrug delivery systems with SN-38 loaded, like nanoparticles, liposomes and micelles, are demonstrated here. Additionally, functionalized nanodrug delivery systems of SN-38 including prodrug and active targeted nanodrug delivery systems and delivery systems designed to overcome drug resistance are also reviewed. At last, challenges for future research in formulation development and clinical translation of SN-38 drug delivery system are discussed.

Salmonella-mediated blood‒brain barrier penetration, tumor homing and tumor microenvironment regulation for enhanced chemo/bacterial glioma therapy

Chemotherapy is an important adjuvant treatment of glioma, while the efficacy is far from satisfactory, due not only to the biological barriers of blood‒brain barrier (BBB) and blood‒tumor barrier (BTB) but also to the intrinsic resistance of glioma cells via multiple survival mechanisms such as up-regulation of P-glycoprotein (P-gp). To address these limitations, we report a bacteria-based drug delivery strategy for BBB/BTB transportation, glioma targeting, and chemo-sensitization. Bacteria selectively colonized into hypoxic tumor region and modulated tumor microenvironment, including macrophages repolarization and neutrophils infiltration. Specifically, tumor migration of neutrophils was employed as hitchhiking delivery of doxorubicin (DOX)-loaded bacterial outer membrane vesicles (OMVs/DOX). By virtue of the surface pathogen-associated molecular patterns derived from native bacteria, OMVs/DOX could be selectively recognized by neutrophils, thus facilitating glioma targeted delivery of drug with significantly enhanced tumor accumulation by 18-fold as compared to the classical passive targeting effect. Moreover, the P-gp expression on tumor cells was silenced by bacteria type III secretion effector to sensitize the efficacy of DOX, resulting in complete tumor eradication with 100% survival of all treated mice. In addition, the colonized bacteria were finally cleared by anti-bacterial activity of DOX to minimize the potential infection risk, and cardiotoxicity of DOX was also avoided, achieving excellent compatibility. This work provides an efficient trans-BBB/BTB drug delivery strategy via cell hitchhiking for enhanced glioma therapy.

Critical roles of linker length in determining the chemical and self-assembly stability of SN38 homodimeric nanoprodrugs

Homodimeric prodrug nanoassemblies (HDPNs) have been widely studied for efficient cancer therapy by virtue of their ultra-high drug loading and distinct nanostructure. However, the development of SN38 HDPNs is still a great challenge due to the rigid planar aromatic ring structure. Improving the structural flexibility of homodimeric prodrugs by increasing the linker length may be a potential strategy for constructing SN38 HDPNs. Herein, three SN38 homodimeric prodrugs with different linker lengths were synthesized. The number of carbon atoms from the disulfide bond to the adjacent ester bond is 1 (denoted as α-SN38-SS-SN38), 2 (β-SN38-SS-SN38), and 3 (γ-SN38-SS-SN38), respectively. Interestingly, we found that α-SN38-SS-SN38 exhibited extremely low yield and poor chemical stability. Additionally, β-SN38-SS-SN38 demonstrated suitable chemical stability but poor self-assembly stability. In comparison, γ-SN38-SS-SN38 possessed good chemical and self-assembly stability, thereby improving the tumor accumulation and antitumor efficacy of SN38. We developed the SN38 HDPNs for the first time and illustrated the underlying molecular mechanism of increasing the linker length to enhance the chemical and self-assembly stability of homodimeric prodrugs. These findings would provide new insights for the rational design of HDPNs with superior performance.

Disulfide Bond-Based SN38 Prodrug Nanoassemblies with High Drug Loading and Reduction-Triggered Drug Release for Pancreatic Cancer Therapy

Purpose

Chemotherapy is a significant and effective therapeutic strategy that is frequently utilized in the treatment of cancer. Small molecular prodrug-based nanoassemblies (SMPDNAs) combine the benefits of both prodrugs and nanomedicine into a single nanoassembly with high drug loading, increased stability, and improved biocompatibility.

Methods

In this study, a disulfide bond inserted 7-ethyl-10-hydroxycamptothecin (SN38) prodrug was rationally designed and then used to prepare nanoassemblies (SNSS NAs) that were selectively activated by rich glutathione (GSH) in the tumor site. The characterization of SNSS NAs and the in vitro and in vivo evaluation of their antitumor effect on a pancreatic cancer model were performed.

Results

In vitro findings demonstrated that SNSS NAs exhibited GSH-induced SN38 release and cytotoxicity. SNSS NAs have demonstrated a passive targeting effect on tumor tissues, a superior antitumor effect compared to irinotecan (CPT-11), and satisfactory biocompatibility with double dosage treatment.

Conclusion

The SNSS NAs developed in this study provide a new method for the preparation of SN38-based nano-delivery systems with improved antitumor effect and biosafety.

Polymeric micelles and cancer therapy: an ingenious multimodal tumor-targeted drug delivery system

Since the beginning of pharmaceutical research, drug delivery methods have been an integral part of it. Polymeric micelles (PMs) have emerged as multifunctional nanoparticles in the current technological era of nanocarriers, and they have shown promise in a range of scientific fields. They can alter the release profile of integrated pharmacological substances and concentrate them in the target zone due to their improved permeability and retention, making them more suitable for poorly soluble medicines. With their ability to deliver poorly soluble chemotherapeutic drugs, PMs have garnered considerable interest in cancer. As a result of their remarkable biocompatibility, improved permeability, and minimal toxicity to healthy cells, while also their capacity to solubilize a wide range of drugs in their micellar core, PMs are expected to be a successful treatment option for cancer therapy in the future. Their nano-size enables them to accumulate in the tumor microenvironment (TME) via the enhanced permeability and retention (EPR) effect. In this review, our major aim is to focus primarily on the stellar applications of PMs in the field of cancer therapeutics along with its mechanism of action and its latest advancements in drug and gene delivery (DNA/siRNA) for cancer, using various therapeutic strategies such as crossing blood-brain barrier, gene therapy, photothermal therapy (PTT), and immunotherapy. Furthermore, PMs can be employed as "smart drug carriers," allowing them to target specific cancer sites using a variety of stimuli (endogenous and exogenous), which improve the specificity and efficacy of micelle-based targeted drug delivery. All the many types of stimulants, as well as how the complex of PM and various anticancer drugs react to it, and their pharmacodynamics are also reviewed here. In conclusion, commercializing engineered micelle nanoparticles (MNPs) for application in therapy and imaging can be considered as a potential approach to improve the therapeutic index of anticancer drugs. Furthermore, PM has stimulated intense interest in research and clinical practice, and in light of this, we have also highlighted a few PMs that have previously been approved for therapeutic use, while the majority are still being studied in clinical trials for various cancer therapies.

Tumor vascular heterogeneity and the impact of subtumoral nanoemulsion biodistribution

Aim: Investigate the heterogeneous tumor tissue organization and examine how this condition can interfere with the passive delivery of a lipid nanoemulsion in two breast cancer preclinical models (4T1 and Ehrlich). Materials & methods: The authors used in vivo image techniques to follow the nanoemulsion biodistribution and microtomography, as well as traditional histopathology and electron microscopy to evaluate the tumor structural characteristics. Results & conclusion: Lipid nanoemulsion was delivered to the tumor, vascular organization depends upon the subtumoral localization and this heterogeneous organization promotes a nanoemulsion biodistribution to the highly vascular peripherical region. Also, the results are presented with a comprehensive mathematical model, describing the differential biodistribution in two different breast cancer models, the 4T1 and Ehrlich models.

Sustained Drug Release from Smart Nanoparticles in Cancer Therapy: A Comprehensive Review

Although nanomedicine has been highly investigated for cancer treatment over the past decades, only a few nanomedicines are currently approved and in the market; making this field poorly represented in clinical applications. Key research gaps that require optimization to successfully translate the use of nanomedicines have been identified, but not addressed; among these, the lack of control of the release pattern of therapeutics is the most important. To solve these issues with currently used nanomedicines (e.g., burst release, systemic release), different strategies for the design and manufacturing of nanomedicines allowing for better control over the therapeutic release, are currently being investigated. The inclusion of stimuli-responsive properties and prolonged drug release have been identified as effective approaches to include in nanomedicine, and are discussed in this paper. Recently, smart sustained release nanoparticles have been successfully designed to safely and efficiently deliver therapeutics with different kinetic profiles, making them promising for many drug delivery applications and in specific for cancer treatment. In this review, the state-of-the-art of smart sustained release nanoparticles is discussed, focusing on the design strategies and performances of polymeric nanotechnologies. A complete list of nanomedicines currently tested in clinical trials and approved nanomedicines for cancer treatment is presented, critically discussing advantages and limitations with respect to the newly developed nanotechnologies and manufacturing methods. By the presented discussion and the highlight of nanomedicine design criteria and current limitations, this review paper could be of high interest to identify key features for the design of release-controlled nanomedicine for cancer treatment.

Engineered bioorthogonal POLY-PROTAC nanoparticles for tumour-specific protein degradation and precise cancer therapy

PROteolysis TArgeting Chimeras (PROTACs) has been exploited to degrade putative protein targets. However, the antitumor performance of PROTACs is impaired by their insufficient tumour distribution. Herein, we present de novo designed polymeric PROTAC (POLY-PROTAC) nanotherapeutics for tumour-specific protein degradation. The POLY-PROTACs are engineered by covalently grafting small molecular PROTACs onto the backbone of an amphiphilic diblock copolymer via the disulfide bonds. The POLY-PROTACs self-assemble into micellar nanoparticles and sequentially respond to extracellular matrix metalloproteinase-2, intracellular acidic and reductive tumour microenvironment. The POLY-PROTAC NPs are further functionalized with azide groups for bioorthogonal click reaction-amplified PROTAC delivery to the tumour tissue. For proof-of-concept, we demonstrate that tumour-specific BRD4 degradation with the bioorthogonal POLY-PROTAC nanoplatform combine with photodynamic therapy efficiently regress tumour xenografts in a mouse model of MDA-MB-231 breast cancer. This study suggests the potential of the POLY-PROTACs for precise protein degradation and PROTAC-based cancer therapy.

Proteolysis targeting chimeras (PROTACs) have emerged as promising cancer therapy agents but have suffered from systemic toxicity issues. Here, the authors report on the creation of polymeric PROTAC nanoparticles for tumour targeting delivery and demonstrate protein degradation in vivo, in combination with photodynamic therapy.

Improvements in Drug-Delivery Properties by Co-Encapsulating Curcumin in SN-38-Loaded Anticancer Polymeric Nanoparticles

SN-38 is an immensely potent anticancer agent although its use necessitates encapsulation to overcome issues of poor solubility and stability. Since SN-38 is a notoriously challenging drug to encapsulate, new avenues to increase encapsulation efficiency in polymer nanoparticles (PNPs) are needed. In this paper, we show that nanoprecipitation with curcumin (CUR) increases SN-38 encapsulation efficiencies in coloaded SN-38/CUR-PNPs based on poly(ε-caprolactone)-block-poly(ethylene glycol) (PCL-b-PEG) by up to a factor of 10. In addition, we find a dramatic decrease in PNP polydispersities, from 0.34 to 0.07, as the initial CUR-to-polymer ratio increases from 0 to 10, with only a modest increase in PNP size (from 40 to 55 nm). Compared to coloaded PNP formation using nanoprecipitation in the bulk or in a gas-liquid, a two-phase microfluidic reactor shows similar trends with respect to CUR content, although improvements in SN-38 encapsulation efficiencies both with and without CUR are found using the microfluidic method. Additional precipitation studies without copolymer suggest that CUR increases the dispersion of SN-38 in the solvent medium of micelle formation, which may contribute to the observed encapsulation enhancement. Cytotoxicity studies of unencapsulated SN-38/CUR mixtures show that addition of CUR does not significantly affect SN-38 potency against either U87 (glioblastoma) or A204 (rhabdomyosarcoma) cell lines. However, we find significant differences in the potencies of SN-38/CUR-PNP formulations depending on initial CUR amounts, with an optimized formulation showing subnanomolar cytotoxicity against A204 cells, significantly more potent than either free SN-38 or PNPs containing only SN-38.

Using GPCRs as Molecular Beacons to Target Ovarian Cancer with Nanomedicines

The five-year survival rate for women with ovarian cancer is very poor despite radical cytoreductive surgery and chemotherapy. Although most patients initially respond to platinum-based chemotherapy, the majority experience recurrence and ultimately develop chemoresistance, resulting in fatal outcomes. The current administration of cytotoxic compounds is hampered by dose-limiting severe adverse effects. There is an unmet clinical need for targeted drug delivery systems that transport chemotherapeutics selectively to tumor cells while minimizing off-target toxicity. G protein-coupled receptors (GPCRs) are the largest family of membrane receptors, and many are overexpressed in solid tumors, including ovarian cancer. This review summarizes the progress in engineered nanoparticle research for drug delivery for ovarian cancer and discusses the potential use of GPCRs as molecular entry points to deliver anti-cancer compounds into ovarian cancer cells. A newly emerging treatment paradigm could be the personalized design of nanomedicines on a case-by-case basis.

A nanotherapeutic strategy to overcome chemoresistance to irinotecan/7-ethyl-10-hydroxy-camptothecin in colorectal cancer

Clinical development of 7-ethyl-10‑hydroxy-camptothecin (SN38), the active metabolite of irinotecan (CPT-11), is hindered by its insolubility and poor stability. Another obstacle is that tumors could become resistant to SN38/CPT-11 through multiple mechanisms involving breast cancer resistance protein (BCRP). Herein one of the most potent and selective BCRP inhibitors, Ko143, is encapsulated into a recently constructed prodrug PEG-S-S-SN38 displaying a high and fixed drug loading, multiple intratumoral stimuli (oxidative stress, GSH and esterase)-responsive drug release and significant in vitro and in vivo superiorities over CPT-11. The obtained "combo" for simultaneous delivery of SN38 and Ko143, named as BI@PEG-SN38, has a high SN38 loading efficacy (14.85 wt.%) and a good Ko143 encapsulation efficacy (3.79%). Through generating panels of human colorectal cancer models expressing altered levels of BCRP via lentiviral transfection and CRISPR-Cas9, characteristics of different drug formulations are carefully evaluated. Impressively, BI@PEG-SN38 nanoparticles effectively reverse chemoresistance to CPT-11 (resistance index dropping from ∼274.00-456.00 to ∼1.70-4.68) and PEG-S-S-SN38 (resistance index dropping from ∼5.83-14.00 to ∼1.70-4.68) in three BCRP-overexpressing cancer cell lines. More importantly, reversal of BCRP-mediated chemoresistance to CPT-11 (P values lower than 0.001-0.0001) and PEG-S-S-SN38 (P values lower than 0.01-0.001) by BI@PEG-SN38 nanoparticles are further confirmed with two panels of colorectal cancer xenograft models in vivo. As the first nano-formulation of Ko143 and the first systemic co-delivery vehicle of SN38/CPT-11 and a BCRP inhibitor, BI@PEG-SN38 provides a new approach for resolving the bottlenecks for clinical translation of SN38 and numerous "chemosensitizers" like Ko143, and exhibits promising applicability in precision cancer medicine. STATEMENT OF SIGNIFICANCE: To resolve the bottlenecks in clinical application of anticancer agents SN38/CPT-11 and the most potent breast cancer resistant protein (BCRP) inhibitor Ko143, a "combo" nanotherapeutic simultaneously delivering SN38 and Ko143 was constructed and named as BI@PEG-SN38. By generating panels of colorectal cancer models, we demonstrate that BI@PEG-SN38 nanoparticles effectively and selectively reversed BCRP-mediated tumor resistance to SN38/CPT-11 in vitro and in vivo. As the first nano-formulation of Ko143 and the first systemic co-delivery vehicle of SN38/CPT-11 and a BCRP inhibitor, BI@PEG-SN38 provides a new strategy for clinical development of SN38 and numerous "chemosensitizers", and exhibits promising applicability in precision cancer medicine. Panels of cancer cell lines established here provides a useful platform for BCRP- and cancer-related research and technology development.

A biocompatible superparamagnetic chitosan-based nanoplatform enabling targeted SN-38 delivery for colorectal cancer therapy

7-Ethyl-10-hydroxycamptothecin (SN-38) as a potent anti-tumor candidate, suffers the constraints from its poor water solubility, pH-dependent lactone ring stability and the lack of efficient delivery system without losing its activity. Herein, biocompatible superparamagnetic chitosan-based nanocomplexes complexing with water-soluble polymeric prodrug poly(L-glutamic acid)-SN-38 (PGA-SN-38) was engineered for efficient delivery of SN-38. The manufacturing process of colloidal complexes was green, expeditious and facile, with one-shot addition of PGA-SN-38 into chitosan solution without using any organic solvent or surfactant. Upon introducing ultra-small-size superparamagnetic nanoparticles (~10 nm), the developed magnetic nanocomplexes exhibited significantly boosted tumor-targeted accumulation and efficient cellular internalization under a local magnetic field. Notably, the magnetic nanocomplexes achieved distinctly superior targeting and anti-tumor efficacy in the established xenograft colorectal cancer model of mice, with high tumor suppression rate up to 81%. Therefore, this superparamagnetic chitosan-based nanocomplex system could provide a promising platform for the targeted delivery of SN-38 in colorectal cancer therapy.

SN38-based albumin-binding prodrug for efficient targeted cancer chemotherapy

Developing new therapeutic strategies that damage tumour cells without harming normal tissues is among the primary obstacles in chemotherapy. In this study, a novel β-glucuronidase-sensitive albumin-binding prodrug was designed and synthesized to selectively deliver the drug SN38 to tumour sites and maximize its efficacy. After intravenous administration, the prodrug Mal-glu-SN38 covalently bound to plasma albumin through the Michael addition, enabling it to accumulate in the tumour and release SN38 when triggered by extracellular β-glucuronidase. Compared to irinotecan, Mal-glu-SN38 displayed a slower plasma clearance and increased drug exposure over time. Moreover, Mal-glu-SN38 caused an increase in tumour-site accumulation of both the albumin-prodrug conjugate and free SN38 released from albumin conjugate when compared with irinotecan. After administration of multiple doses, Mal-glu-SN38 also significantly delayed the tumour growth, resulting in an impressive reduction or even disappearance of tumours (67% of mice cured) without causing any observable side effects.

Dynamic nanoassemblies of nanomaterials for cancer photomedicine

Photomedicine has long been used for treating cancerous diseases. With advances in chemical and material sciences, various types of light-activated photosensitizers (PSs) have been developed for effective photodynamic therapy (PDT) and photothermal therapy (PTT). However, conventional organic/inorganic materials-based PSs lack disease recognition capability and show limited therapeutic effects in addition to side effects. Recently, intelligent dynamic nanoassemblies that are activated in a tumor environment have been extensively researched to target diseased tissues more effectively, for increasing therapeutic effectiveness while minimizing side effects. This paper presents the latest dynamic nanoassemblies for effective PDT or PTT and combination phototherapies, including immunotherapy and image-guided therapy. Dynamic self-assembly exhibits great potential for clinical translation in diagnosis and treatment through its integrated versatility. Nanoassemblies based on multidisciplinary technology are a promising technique for treating incurable cancerous diseases in the future.

Comparison of Efficacy and Peripheral Neuropathy of Solvent-based Paclitaxel with Paclitaxel Poliglumex and NK105: A Systematic Review and Metaanalysis

Background and Introduction: Peripheral neuropathy is one of the most common dose-limiting side effects of solvent-based paclitaxel. Paclitaxel poliglumex (PPX) and NK105 were developed to overcome the paclitaxel induced peripheral neuropathy. However, the incidence of peripheral neuropathy induced by PPX and NK105 was reported higher than solvent-based paclitaxel, but evidence remains inconsistent.

METHODS

The article was reported in accordance with PRISMA Guidelines (Registration number: CRD42021245313). We conducted a meta-analysis to compare the incidence and severity of peripheral neuropathy between solvent-based paclitaxel, PPX and NK105 mono-chemotherapy.

RESULTS

Results revealed that no significant difference exists between the incidence of all grade peripheral neuropathy among the solvent-based paclitaxel, PPX and NK105 treated groups. While, the incidence of high grade peripheral neuropathy induced by NK105 was lower than two other groups. Moreover, the overall survival was not improved in PPX compared with other groups. However, NK105 demonstrated significant longer overall survival in patients with cancer.

CONCLUSION

Current evidence suggests more attention should be paid to the paclitaxel poliglumex re-formulation.

Recent trends in bioresponsive linker technologies of Prodrug-Based Self-Assembling nanomaterials

Prodrugs are designed to improve pharmaceutical properties of potent compounds and represent a central approach in drug development. The success of the prodrug strategy relies on incorporation of a reversible linkage facilitating controlled release of the parent drug. While prodrug approaches enhance pharmacokinetic properties over their parent drug, they still face challenges in absorption, distribution, metabolism, elimination, and toxicity (ADMET). Conjugating a drug to a carrier molecule such as a polymer can create an amphiphile that self-assembles into nanoparticles. These nanoparticles display prolonged blood circulation and passive targeting ability. Furthermore, the drug release can be tailored using a variety of linkers between the parent drug and the carrier molecule. In this review, we introduce the concept of self-assembling prodrugs and summarize different approaches for controlling the drug release with a focus on the linker technology. We also summarize recent clinical trials, discuss the emerging challenges, and provide our perspective on the utility and future potential of this technology.

Recent Advances in Improved Anticancer Efficacies of Camptothecin Nano-Formulations: A Systematic Review

Camptothecin (CPT), a natural plant alkaloid, has indicated potent antitumor activities via targeting intracellular topoisomerase I. The promise that CPT holds in therapies is restricted through factors that include lactone ring instability and water insolubility, which limits the drug oral solubility and bioavailability in blood plasma. Novel strategies involving CPT pharmacological and low doses combined with nanoparticles have indicated potent anticancer activity in vitro and in vivo. This systematic review aims to provide a comprehensive and critical evaluation of the anticancer ability of nano-CPT in various cancers as a novel and more efficient natural compound for drug development. Studies were identified through systematic searches of PubMed, Scopus, and ScienceDirect. Eligibility checks were performed based on predefined selection criteria. Eighty-two papers were included in this systematic review. There was strong evidence for the association between antitumor activity and CPT treatment. Furthermore, studies indicated that CPT nano-formulations have higher antitumor activity in comparison to free CPT, which results in enhanced efficacy for cancer treatment. The results of our study indicate that CPT nano-formulations are a potent candidate for cancer treatment and may provide further support for the clinical application of natural antitumor agents with passive targeting of tumors in the future.

Contemporary Mouse Models in Glioma Research

Despite advances in understanding of the molecular pathogenesis of glioma, outcomes remain dismal. Developing successful treatments for glioma requires faithful in vivo disease modeling and rigorous preclinical testing. Murine models, including xenograft, syngeneic, and genetically engineered models, are used to study glioma-genesis, identify methods of tumor progression, and test novel treatment strategies. Since the discovery of highly recurrent isocitrate dehydrogenase (IDH) mutations in lower-grade gliomas, there is increasing emphasis on effective modeling of IDH mutant brain tumors. Improvements in preclinical models that capture the phenotypic and molecular heterogeneity of gliomas are critical for the development of effective new therapies. Herein, we explore the current status, advancements, and challenges with contemporary murine glioma models.

Strategies for the Development of pH-Responsive Synthetic Polypeptides and Polymer-Peptide Hybrids: Recent Advancements

Synthetic polypeptides and polymer-peptide hybrid materials have been successfully implemented in an array of biomedical applications owing to their biocompatibility, biodegradability and ability to mimic natural proteins. In addition, these materials have the capacity to form complex supramolecular structures, facilitate specific biological interactions, and incorporate a diverse selection of functional groups that can be used as the basis for further synthetic modification. Like conventional synthetic polymers, polypeptide-based materials can be designed to respond to external stimuli (e.g., light and temperature) or changes in the environmental conditions (e.g., redox reactions and pH). In particular, pH-responsive polypeptide-based systems represent an interesting avenue for the preparation of novel drug delivery systems that can exploit physiological or pathological pH variations within the body, such as those that arise in the extracellular tumour microenvironment, intracellularly within endosomes/lysosomes, or during tissue inflammation. Here, we review the significant progress made in advancing pH-responsive polypeptides and polymer-peptide hybrid materials during the last five years, with a particular emphasis on the manipulation of ionisable functional groups, pH-labile linkages, pH-sensitive changes to secondary structure, and supramolecular interactions.

Self-assembly delivery system based on small-molecule camptothecin prodrug for treatment of colorectal carcinoma

The aim of this study was to prepare small-molecule camptothecin (CPT) prodrugs and evaluate their effectiveness in colorectal carcinoma therapy. Prodrug nanoparticles (NPs) were physicochemically characterized and evaluated for their cytotoxicity in human colon cancer (HCT116) cell lines. The antitumor efficacy of the NPs was evaluated in HCT116 tumor-bearing mice. The prepared NPs exhibited high drug loading capacity (32% of CPT w/w) and also kept a high active lactone fraction of CPT (>85%) during circulation. The NPs were internalized into tumor cells efficiently compared with free drug and significantly enhanced the drug's therapeutic efficacy. The developed small-molecule CPT prodrug NPs could be a promising strategy in the clinical therapy of colorectal carcinoma.

Efficient Suppression of Abdominal Aortic Aneurysm Expansion in Rats through Systemic Administration of Statin-Loaded Nanomedicine

Abdominal aortic aneurysm (AAA) is a life-threatening disease. However, no systemically injectable drug has been approved for AAA treatment due to low bioavailability. Polymeric micelles are nanomedicines that have the potential to improve therapeutic efficacy by selectively delivering drugs into disease sites, and research has mainly focused on cancer treatments. Here, we developed a statin-loaded polymeric micelle to treat AAAs in rat models. The micelle showed medicinal efficacy by preventing aortic aneurysm expansion in a dose-dependent manner. Furthermore, the micelle-injected group showed decreased macrophage infiltration and decreased matrix metalloproteinase-9 activity in cases of AAA.

Development of Self-Associating SN-38-Conjugated Poly(ethylene oxide)-Poly(ester) Micelles for Colorectal Cancer Therapy

The clinical use of 7-ethyl-10-hydroxy-camptothecin (SN-38), which is the active metabolite of irinotecan, has been hampered because of its practical water-insolubility. In this study, we successfully synthesized two self-associating SN-38-polymer drug conjugates to improve the water-solubility of SN-38, while retaining its anticancer activity. The polymeric micellar SN-38 conjugates were composed of either methoxy-poly(ethylene oxide)-block-poly(α-benzyl carboxylate-ε-caprolactone) conjugated to SN-38 at the PBCL end (mPEO-b-PBCL/SN-38) or mPEO-block-poly(α-carboxyl-ε-caprolactone) attached to SN-38 from the pendent-free carboxyl site (mPEO-b-PCCL/SN-38). The chemical structure of block copolymers was confirmed by ¹H NMR. The physicochemical characterizations of their self-assembled structures including size, surface charge, polydispersity, critical micellar concentration, conjugation content and efficiency, morphology, kinetic stability, and in vitro release of SN-38 were compared between the two formulations. In vitro anticancer activities were evaluated by measuring cellular cytotoxicity and caspase activation by MTS and Caspase-Glo 3/7 assays, respectively. The hemolytic activity of both micellar structures against rat red blood cells was also measured. The results showed the formation of SN-38-polymeric micellar conjugates at diameters < 50 nm with a narrow size distribution and sustained release of SN-38 for both structures. The loading content of SN-38 in mPEO-b-PBCL and mPEO-b-PCCL were 11.47 ± 0.10 and 12.03 ± 0.17 (% w/w), respectively. The mPEO-b-PBCL/SN-38, end-capped micelles were kinetically more stable than mPEO-b-PCCL/SN-38. The self-assembled mPEO-b-PBCL/SN-38 and mPEO-b-PCCL/SN-38 micelles resulted in significantly higher cytotoxic effects than irinotecan against human colorectal cancer cell lines HCT116, HT-29, and SW20. The CRC cells were found to be 70-fold to 330-fold more sensitive to micellar SN-38 than irinotecan, on average. Both SN-38-incorporated micelles showed two-fold higher caspase-3/7 activation levels than irinotecan. The mPEO-b-PBCL/SN-38 micelles were not hemolytic, but mPEO-b-PCCL/SN-38 showed some hemolysis. The overall results from this study uphold mPEO-b-PBCL/SN-38 over mPEO-b-PCCL/SN-38 micellar formulation as an effective delivery system of SN-38 that warrants further preclinical investigation.

A multifunctional SN38-conjugated nanosystem for defeating myelosuppression and diarrhea induced by irinotecan in esophageal cancer

A combination of chemotherapy and phototherapy has been proposed as a promising treatment for esophageal cancer (EC). Irinotecan as a first-line treatment option is widely prescribed for metastatic EC, however, its clinical application is extremely restricted by the low conversion rate to SN38, severe myelosuppression and diarrhea. As a more potent active metabolite of irinotecan, SN38 is a better substitution for irinotecan, but the poor water solubility and the difficulty of encapsulation hindered its medical application. Herein, a multifunctional SN38-conjugated nanosystem (FA-PDA@PZM/SN38@BSA-MnO2, denoted as FA-PPSM) is designed for overcoming the above-mentioned drawbacks and achieving collaborative chemotherapy, photodynamic therapy (PDT) and photothermal therapy (PTT). The tumor acidic microenvironment induces decomposition of BSA-MnO2 nanoparticles into O2 and Mn2+, thus enhancing oxygen-dependent PDT efficacy; meanwhile, Mn2+ can be employed as a magnetic resonance imaging (MRI) contrast agent. Under 650 and 808 nm laser irradiation, the FA-PPSM nanocomposites exhibit superior antitumor efficacy in Eca-109-tumor bearing mice. Notably, there is low gastrointestinal toxicity and myelosuppression in the FA-PPSM treated mice compared with those treated with irinotecan (alone). Taken together, this work highlights the great potential of the FA-PPSM nanocomposites for MRI-guided chemotherapy in combination with endoscopic light therapy for esophageal cancer.

Polymeric micelles for anticancer drug delivery

Polymeric micelles have gained interest as novel drug delivery systems for the treatment and diagnosis of cancer, as they offer several advantages over conventional drug therapies. This includes drug targeting to tumor tissue, in vivo biocompatibility and biodegradability, prolonged circulation time, enhanced accumulation, retention of the drug loaded micelle in the tumor and decreased side effects. This article provides an overview on the current state of micellar formulations as nanocarriers for anticancer drugs and their effectiveness in cancer therapeutics, including their clinical status. The type of copolymers used, their physicochemical properties and characterization as well as recent developments in the design of functional polymeric micelles are highlighted. The article also presents the design and outcomes of various types of stimuli-responsive polymeric micelles.

Polymeric micelles for anticancer drug delivery

Polymeric micelles have gained interest as novel drug delivery systems for the treatment and diagnosis of cancer, as they offer several advantages over conventional drug therapies. This includes drug targeting to tumor tissue, in vivo biocompatibility and biodegradability, prolonged circulation time, enhanced accumulation, retention of the drug loaded micelle in the tumor and decreased side effects. This article provides an overview on the current state of micellar formulations as nanocarriers for anticancer drugs and their effectiveness in cancer therapeutics, including their clinical status. The type of copolymers used, their physicochemical properties and characterization as well as recent developments in the design of functional polymeric micelles are highlighted. The article also presents the design and outcomes of various types of stimuli-responsive polymeric micelles.

Using Polypeptide Bearing Furan Side Chains as a General Platform to Achieve Highly Effective Preparation of Smart Glycopolypeptide Analogue-Based Nano-Prodrugs for Cancer Treatment

Although several synthetic polypeptide-based nano-prodrugs (NPDs) have entered clinical trials for cancer treatment, achieving a highly effective production of the NPDs for clinical translation remains a challenge. Herein, we develop a typical preparation of pH/glutathione (GSH) dual-responsive glycopolypeptide analogue NPDs having a high drug capsulation/loading efficiency of ca. 93% and ca. 27% even based on ring-opening polymerization (ROP) of a novel and general furan-containing N-carboxyanhydride (NCA) monomer, which facilitates the Diels-Alder (D-A) side-chain functionalization by maleimide modified chemotherapy drug without using any reactive additives. High reactivity of the D-A reaction resulting in the high preparation efficiency of the NPDs is confirmed by ¹H NMR and density functional theory (DFT) calculations. The self-assembled properties as well as the dual-responsiveness of the NPDs are systemically studied by particle size and zeta potential assay, transmission electron microscopy and drug-delivery dynamics. The cell uptake mechanism, intracellular drug distribution, in vitro/vivo antitumor activity evaluations and the main organ damages of the NPDs are all investigated. Our work can provide a good solution to solve the inefficient fabrication of the smart synthetic polypeptide-based micelles for cancer treatment by following this general and sophisticated platform.

Sulfur dioxide signaling molecule-responsive polymeric nanoparticles

Stimuli-responsive polymer nano-capsules toward a specific signaling molecule show great potential in the fabrication of smart and efficient controlled/targeted drug vehicles. Herein, we design and synthesize a PEG45-b-PVPOP14 diblock copolymer (PEG = poly(ethylene glycol) and PVPOP = poly(4-vinylphenyl 4-oxopentanoate), the subscripts representing the number of repeat units of each block) with levulinate-protected phenol side groups. The PEG45-b-PVPOP14 diblock copolymer could self-assemble to form large compound micelles in aqueous media. Since the core of the large compound micelles formed contains both hydrophilic PEG and hydrophobic PVPOP domains, this kind of micelle is able to load both hydrophobic and hydrophilic species within the core. The ester moiety of levulinate-protected phenol can be selectively cleaved upon incubation with a sulfite, a derivative of SO2 in aqueous media, to give phenol groups. Thus, the sulfite exhibits the ability to alter the amphiphilicity and further the self-assembled behavior of PEG45-b-PVPOP14. The release of payloads in the core of micelles can be accelerated by triggering of the sulfite. Significantly, the nano-capsule of PEG45-b-PVPOP14 shows specific response to the sulfite (SO2) with slight interference of other bio-species, such as Cys, GSH and Hcy. As far as we are aware, this is the first example of a nano-capsule with sulfite (SO2) specific responsiveness. We envisage that this polymer model could broaden the scope of biological signaling molecule responsive macromolecular systems and provide a new platform to fabricate SO2-responsive biomedicine materials.

Quercetin Loaded Nanoparticles in Targeting Cancer: Recent Development

The spread of metastatic cancer cell is the main cause of death worldwide. Cellular and molecular basis of the action of phytochemicals in the modulation of metastatic cancer highlights the importance of fruits and vegetables. Quercetin is a natural bioflavonoid present in fruits, vegetables, seeds, berries, and tea. The cancer-preventive activity of quercetin is well documented due to its anti-inflammatory, anti-proliferative and anti-angiogenic activities. However, poor water solubility and delivery, chemical instability, short half-life, and low-bioavailability of quercetin limit its clinical application in cancer chemoprevention. A better understanding of the molecular mechanism of controlled and regulated drug delivery is essential for the development of novel and effective therapies. To overcome the limitations of accessibility by quercetin, it can be delivered as nanoconjugated quercetin. Nanoconjugated quercetin has attracted much attention due to its controlled drug release, long retention in tumor, enhanced anticancer potential, and promising clinical application. The pharmacological effect of quercetin conjugated nanoparticles typically depends on drug carriers used such as liposomes, silver nanoparticles, silica nanoparticles, PLGA (Poly lactic-co-glycolic acid), PLA (poly(D,L-lactic acid)) nanoparticles, polymeric micelles, chitosan nanoparticles, etc. In this review, we described various delivery systems of nanoconjugated quercetin like liposomes, silver nanoparticles, PLGA (Poly lactic-co-glycolic acid), and polymeric micelles including DOX conjugated micelles, metal conjugated micelles, nucleic acid conjugated micelles, and antibody-conjugated micelles on in vitro and in vivo tumor models; as well as validated their potential as promising onco-therapeutic agents in light of recent updates.

Helix Self-Assembly Behavior of Amino Acid-Modified Camptothecin Prodrugs and Its Antitumor Effect

For effective antitumor treatment, it is important to increase the water solubility of hydrophobic antitumor drugs and improve their cell absorption efficiency and nuclear transmission capacity. Here, we use endogenous hydrophilic arginine to modify camptothecin (CPT) to increase its water solubility. Surprisingly, the modified CPT can self-assemble into helical nanofibers through intermolecular π-π stacking and hydrophilic-hydrophobic interactions. Prodrug-based nanofibers were better endocytosed into the nucleus than their nonassembled CPT. Moreover, in vivo, such nanofibers had a longer blood circulation time and a better ability to accumulate in the tumor site. Further, we found that the cationic nanofibers can be combined with the anionic cisplatin-polyglutamic acid through electrostatic interaction to achieve a combined antitumor effect. This provides a new idea for achieving more effective cancer chemotherapy effects.

Recent advances in nanotheranostics for triple negative breast cancer treatment

Triple-negative breast cancer (TNBC) is the most complex and aggressive type of breast cancer encountered world widely in women. Absence of hormonal receptors on breast cancer cells necessitates the chemotherapy as the only treatment regime. High propensity to metastasize and relapse in addition to poor prognosis and survival motivated the oncologist, nano-medical scientist to develop novel and efficient nanotherapies to solve such a big TNBC challenge. Recently, the focus for enhanced availability, targeted cellular uptake with minimal toxicity is achieved by nano-carriers. These smart nano-carriers carrying all the necessary arsenals (drugs, tracking probe, and ligand) designed in such a way that specifically targets the TNBC cells at site. Articulating the targeted delivery system with multifunctional molecules for high specificity, tracking, diagnosis, and treatment emerged as theranostic approach. In this review, in addition to classical treatment modalities, recent advances in nanotheranostics for early and effective diagnostic and treatment is discussed. This review highlighted the recently FDA approved immunotherapy and all the ongoing clinical trials for TNBC, in addition to nanoparticle assisted immunotherapy. Futuristic but realistic advancements in artificial intelligence (AI) and machine learning not only improve early diagnosis but also assist clinicians for their workup in TNBC. The novel concept of Nanoparticles induced endothelial leakiness (NanoEL) as a way of tumor invasion is also discussed in addition to classical EPR effect. This review intends to provide basic insight and understanding of the novel nano-therapeutic modalities in TNBC diagnosis and treatment and to sensitize the readers for continue designing the novel nanomedicine. This is the first time that designing nanoparticles with stoichiometric definable number of antibodies per nanoparticle now represents the next level of precision by design in nanomedicine.

Species-specific optimization of PEG~SN-38 prodrug pharmacokinetics and antitumor effects in a triple-negative BRCA1-deficient xenograft

PURPOSE

Optimal efficacy of a macromolecular prodrug requires balancing the rate of drug release with the rate of prodrug elimination. Since circulating macromolecules have different elimination rates in different species, a prodrug optimal for one species will likely not be for another. The objectives of this work were (a) to develop an approach to optimize pharmacokinetics of a PEG~SN-38 prodrug in a particular species, (b) to use the approach to predict the pharmacokinetics of various prodrugs of SN-38 in the mouse and human, and (c) to develop a PEG~SN-38 conjugate that is optimized for mouse tumor models.

METHODS

We developed models that describe the pharmacokinetics of a drug released from a prodrug by the relationship between the rates of drug release and elimination of the prodrug. We tested the model by varying the release rate of SN-38 from PEG~SN-38 conjugates in the setting of a constant prodrug elimination rate in the mouse. Finally, we tested the antitumor efficacy of a PEG~SN-38 optimized for the mouse.

RESULTS

Optimization of a PEG~SN-38 prodrug was achieved by adjusting the rate of SN-38 release such that the ratio of t_1/2,β of released SN-38 to the t_1/2 of prodrug elimination was 0.2-0.8. Using this approach, we could rationalize the efficacy of previous PEGylated SN-38 prodrugs in the mouse and human. Finally, a mouse-optimized PEG~SN-38 showed remarkable antitumor activity in BRCA1-deficient MX-1 xenografts; a single dose gave tumor regression, suppression, and shrinkage of massive tumors.

CONCLUSIONS

The efficacy of a macromolecular prodrug can be optimized for a given species by balancing the rate of drug release from the carrier with the rate of prodrug elimination.

Microfluidic encapsulation of SN-38 in block copolymer nanoparticles: effect of hydrophobic block composition on loading and release properties

A gas–liquid microfluidic reactor was used to prepare polymer nanoparticles (PNPs) containing the drug 7-ethyl-10-hydroxy camptothecin (SN-38) from a series of poly(methyl caprolactone-co-caprolactone)-b-poly(ethylene oxide) (P(MCL-co-CL)-b-PEO) amphiphilic block copolymers with variable MCL content in the hydrophobic block. All three copolymers formed spheres with ∼20 nm core diameters by TEM, although some rigid rod-like aggregates were also formed by the PMCL-50 and PMCL-75 copolymers. SN-38 encapsulation efficiencies (EE = 2.7%–3.0%) and loading levels (DL = 2.0%–2.9%) were similar for the three copolymers. In vitro release kinetics became significantly slower as the MCL content increased, with release half times increasing monotonically from 3.4 to 6.2 h as the MCL content of the hydrophobic block increased from 50% to 100%. The ability to systematically tune release half times via controlled variation in the hydrophobic block composition, while maintaining constant PNP size and loading levels, represents an intriguing chemical handle for the optimization of SN-38 nanomedicines.

Synthesis of a SN38 prodrug grafted to amphiphilic phosphorylcholine polymers and their prodrug miceller properties

Polymer prodrug micelles, combining the advantages of prodrugs and polymer micelles, can greatly improve the solubility, permeability and stability of drugs.

Microfluidic Manufacturing of SN-38-Loaded Polymer Nanoparticles with Shear Processing Control of Drug Delivery Properties

Two-phase gas-liquid microfluidic reactors provide shear processing control of SN-38-loaded polymer nanoparticles (SN-38-PNPs). We prepare SN-38-PNPs from the block copolymer poly(methyl caprolactone- co-caprolactone)- block-poly(ethylene oxides) (P(MCL- co-CL)- b-PEO) using bulk and microfluidic methods and at different drug-to-polymer loading ratios and on-chip flow rates. We show that, as the microfluidic flow rate ( Q) increases, encapsulation efficiency and drug loading increase and release half times increase. Slower SN-38 release is obtained at the highest Q value ( Q = 400 μL/min) than is achieved using a conventional bulk preparation method. For all SN-38-PNP formulations, we find a dominant population (by number) of nanosized particles (<50 nm) along with a small number of larger aggregates (>100 nm). As Q increases, the size of aggregates decreases through a minimum and then increases, attributed to a flow-variable competition of shear-induced particle breakup and shear-induced particle coalescence. IC₂₅ and IC₅₀ values of the various SN-38-PNPs against MCF-7 cells show strong flow rate dependencies that mirror trends in particle size. SN-38-PNPs manufactured on-chip at intermediate flow rates show both minimum particle sizes and maximum potencies with a significantly lower IC₂₅ value than the bulk-prepared sample. Compared to conventional bulk methods, microfluidic shear processing in two-phase reactors provides controlled manufacturing routes for optimizing and improving the properties of SN-38 nanomedicines.