A self-assembled pH/enzyme dual-responsive prodrug with PEG deshielding for multidrug-resistant tumor therapy

ROS-responsive oridonin and dihydroartemisinin hetero-polymeric prodrug NPs for potentiating ferroptosis in gastric cancer by disrupting redox balance

Gastric cancer presents a significant global health concern, with conventional therapies often limited in effectiveness. The abnormal redox balance in gastric cancer cells may represent a breakthrough in the treatment of gastric cancer. In this study, we report for the first time the development of reactive oxygen species (ROS)-sensitive hetero-polymeric prodrug nanoparticles (NPs) designed for the co-delivery of the Chinese herbal extract oridonin (ORI) and dihydroartemisinin (DHA) in combination therapy for gastric cancer. This strategy aims to disrupt the intracellular redox balance and ultimately induce ferroptosis in gastric cancer cells. The ROS-responsive ORI and DHA polymeric prodrug were synthesised by conjugating ORI or DHA to poly(ethylene glycol)-block-poly(L-lysine) (PEG-b-PLL) via a ROS-sensitive linker thioketal (TK). The resulting polymeric prodrugs self-assemble in water to form NPs OD-M. After internalization by gastric cancer cells, OD-M released ORI and DHA in response to high ROS conditions within cancer cells. The released ORI reacts with GSH to induce GSH depletion while DHA amplifies intracellular ROS levels, ultimately inducing ferroptosis in gastric cancer cells. Experimental results demonstrate that OD-M acts as both a GSH scavenger and ROS generator, effectively disrupting intracellular redox balance, inducing ferroptosis, and exhibiting effective anticancer efficacy in vitro and in vivo, offering a departure from traditional methods.

Progress in Research of Nanotherapeutics for Overcoming Multidrug Resistance in Cancer

Chemotherapy has been widely applied in oncotherapy. However, the development of multidrug resistance (MDR) has diminished the effectiveness of anticancer drugs against tumor cells. Such resistance often results in tumor recurrence, metastasis, and patient death. Fortunately, nanoparticle-based drug delivery systems provide a promising strategy by codelivery of multiple drugs and MDR reversal agents and the skillful, flexible, smart modification of drug targets. Such systems have demonstrated the ability to bypass the ABC transporter biological efflux mechanisms due to drug resistance. Hence, how to deliver drugs and exert potential antitumor effects have been successfully explored, applied, and developed. Furthermore, to overcome multidrug resistance, nanoparticle-based systems have been developed due to their good therapeutic effect, low side effects, and high tumor metastasis inhibition. In view of this, we systematically discuss the molecular mechanisms and therapeutic strategies of MDR from nanotherapeutics. Finally, we summarize intriguing ideas and future trends for further research in overcoming MDR.

LIFU/MMP-2 dual-responsive release of repurposed drug disulfiram from nanodroplets for inhibiting vasculogenic mimicry and lung metastasis in triple-negative breast cancer

BACKGROUND

Vasculogenic mimicry (VM), when microvascular channels are formed by cancer cells independent of endothelial cells, often occurs in deep hypoxic areas of tumors and contributes to the aggressiveness and metastasis of triple-negative breast cancer (TNBC) cells. However, well-developed VM inhibitors exhibit inadequate efficacy due to their low drug utilization rate and limited deep penetration. Thus, a cost-effective VM inhibition strategy needs to be designed for TNBC treatment.

RESULTS

Herein, we designed a low-intensity focused ultrasound (LIFU) and matrix metalloproteinase-2 (MMP-2) dual-responsive nanoplatform termed PFP@PDM-PEG for the cost-effective and efficient utilization of the drug disulfiram (DSF) as a VM inhibitor. The PFP@PDM-PEG nanodroplets effectively penetrated tumors and exhibited substantial accumulation facilitated by PEG deshielding in a LIFU-mediated and MMP-2-sensitive manner. Furthermore, upon exposure to LIFU irradiation, DSF was released controllably under ultrasound imaging guidance. This secure and controllable dual-response DSF delivery platform reduced VM formation by inhibiting COL1/pro-MMP-2 activity, thereby significantly inhibiting tumor progression and metastasis.

CONCLUSIONS

Considering the safety of the raw materials, controlled treatment process, and reliable repurposing of DSF, this dual-responsive nanoplatform represents a novel and effective VM-based therapeutic strategy for TNBC in clinical settings.

A review of matrix metalloproteinase-2-sensitive nanoparticles as a novel drug delivery for tumor therapy

Matrix metalloproteinase-2 (MMP-2)-responsive nanodrug vehicles have garnered significant attention as antitumor drug delivery systems due to the extensive research on matrix metalloproteinases (MMPs) within the tumor extracellular matrix (ECM). These nanodrug vehicles exhibit stable circulation in the bloodstream and accumulate specifically in tumors through various mechanisms. Upon reaching tumor tissues, their structures are degraded in response to MMP-2 within the ECM, resulting in drug release. This controlled drug release significantly increases drug concentration within tumors, thereby enhancing its antitumor efficacy while minimizing side effects on normal organs. This review provides an overview of MMP-2 characteristics, enzyme-sensitive materials, and current research progress regarding their application as MMP-2-responsive nanodrug delivery system for anti-tumor drugs, as well as considering their future research prospects. In conclusion, MMP-2-sensitive drug delivery carriers have a broad application in all kinds of nanodrug delivery systems and are expected to become one of the main means for the clinical development and application of nanodrug delivery systems in the future.

Stimuli responsiveness of recent biomacromolecular systems (concept to market): A review

Stimuli responsive delivery systems, also known as smart/intelligent drug delivery systems, are specialized delivery vehicles designed to provide spatiotemporal control over drug release at target sites in various diseased conditions, including tumor, inflammation and many others. Recent advances in the design and development of a wide variety of stimuli-responsive (pH, redox, enzyme, temperature) materials have resulted in their widespread use in drug delivery and tissue engineering. The aim of this review is to provide an insight of recent nanoparticulate drug delivery systems including polymeric nanoparticles, dendrimers, lipid-based nanoparticles and the design of new polymer-drug conjugates (PDCs), with a major emphasis on natural along with synthetic commercial polymers used in their construction. Special focus has been placed on stimuli-responsive polymeric materials, their preparation methods, and the design of novel single and multiple stimuli-responsive materials that can provide controlled drug release in response a specific stimulus. These stimuli-sensitive drug nanoparticulate systems have exhibited varying degrees of substitution with enhanced in vitro/in vivo release. However, in an attempt to further increase drug release, new dual and multi-stimuli based natural polymeric nanocarriers have been investigated which respond to a mixture of two or more signals and are awaiting clinical trials. The translation of biopolymeric directed stimuli-sensitive drug delivery systems in clinic demands a thorough knowledge of its mechanism and drug release pattern in order to produce affordable and patient friendly products.

A mitochondria-targeting self-assembled carrier-free lonidamine nanodrug for redox-activated drug release to enhance cancer chemotherapy

Mitochondria play a vital role in maintaining cellular homeostasis. In recent years, studies have found that mitochondria have an important role in the occurrence and development of tumors, and targeting mitochondria has become a new strategy for tumor treatment. Lonidamine (LND), as a hexokinase inhibitor, can block the energy supply and destroy mitochondria. However, poor water solubility and low mitochondrial selectivity limit its clinical application. To overcome these obstacles, we report redox-activated self-assembled carrier-free nanoparticles (Cy-TK-LND NPs) based on a small molecule prodrug, in which photosensitizer IR780 (Cy) which targets mitochondria is conjugated to LND via a sensitive thioketal (TK) linker. Intracellular oxidative stress induced by laser radiation leads to the responsive cleavage of Cy-TK-LND NPs, facilitating the release of free LND into mitochondria. Subsequently, LND damages mitochondria, triggering the apoptosis pathway. The results show the effective killing effect of Cy-TK-LND NPs on cancer cells in vitro and in vivo. The IC50 value of irradiated Cy-TK-LND NPs is 5-fold lower than that of free LND. Moreover, tumor tissue section staining results demonstrate that irradiated Cy-TK-LND NPs induce necrosis and apoptosis of tumor cells, upregulate cytochrome C and pro-apoptotic Bax, and downregulate anti-apoptotic Bcl-2. Generally, Cy-TK-LND NPs exhibit efficient mitochondria-targeted delivery to improve the medicinal availability of LND. Accordingly, such a carrier-free prodrug-based nanomedicine holds promise as an effective cancer chemotherapy strategy.

Enhancing Photothermal Therapy Efficacy by In Situ Self-Assembly in Glioma

The residence time of some small molecular imaging and therapeutic agents in tumor tissue is short and the molecules can be easily dispersed, which decreases treatment efficacy. Therefore, methods that enhance oncotherapy performance are of significant importance. Here, we report an in situ self-assembly strategy aimed at enhancing the photothermal therapy of glioblastomas. The probe, ICG-PEP-c(RGD)fk, consisted of a glutathione-reactive self-assembling polypeptide as the skeleton, indocyanine green (ICG) as a theranostic agent, and cyclic Arg-Gly-Asp [c(RGD)fk] peptides as the targeting group. ICG-PEP-c(RGD)fk was synthesized and found to be assembled in the glutathione environment at 9.446 μM in vitro. Human glioblastoma cell line U87MG-luc with high integrin αvβ3 expression was applied to invivo experiments. ICG-PEP-c(RGD)fk provided clearer tumor imaging and had a tumor retention time of 6.12 times longer than that of ICG-c(RGD)fk. In therapeutic experiments, ICG-PEP-c(RGD)fk significantly suppressed glioblastoma growth and the tumor volume was 2.61 times smaller than in the ICG-c(RGD)fk group at the end of the observation period. Moreover, the median survival time of ICG-PEP-c(RGD)fk group was significantly improved by 2.78 times compared with that of the control group. In conclusion, glutathione-reactive self-assembling peptides are capable of increasing the tumor retention time and improving the photothermal therapeutic effect. The in situ self-assembly strategy is a potential and feasible method to enhance oncotherapy.

Nanoparticle based medicines: approaches for evading and manipulating the mononuclear phagocyte system and potential for clinical translation

For decades, nanomedicines have been reported as a potential means to overcome the limitations of conventional drug delivery systems by reducing side effects, toxicity and the non-ideal pharmacokinetic behaviour typically exhibited by small molecule drugs. However, upon administration many nanoparticles prompt induction of host inflammatory responses due to recognition and uptake by macrophages, eliminating up to 95% of the administered dose. While significant advances in nanoparticle engineering and consequent therapeutic efficacy have been made, it is becoming clear that nanoparticle recognition by the mononuclear phagocyte system (MPS) poses an impassable junction in the current framework of nanoparticle development. Hence, this has negative consequences on the clinical translation of nanotechnology with respect to therapeutic efficacy, systemic toxicity and economic benefit. In order to improve the translation of nanomedicines from bench-to-bedside, there is a requirement to either modify nanomedicines in terms of how they interact with intrinsic processes in the body, or modulate the body to be more accommodating for nanomedicine treatments. Here we provide an overview of the current standard for design elements of nanoparticles, as well as factors to consider when producing nanomedicines that have minimal MPS-nanoparticle interactions; we explore this landscape across the cellular to tissue and organ levels. Further, rather than designing materials to suit the body, a growing research niche involves modulating biological responses to administered nanomaterials. We here discuss how developing strategic methods of MPS 'pre-conditioning' with small molecule or biological drugs, as well as implementing strategic dosing regimens, such as 'decoy' nanoparticles, is essential to increasing nanoparticle therapeutic efficacy. By adopting such a perspective, we hope to highlight the increasing trends in research dedicated to improving nanomedicine translation, and subsequently making a positive clinical impact.

Legumain-mediated self-assembly of 131I-labelled agent for targeted radiotherapy of tumor

Targeted radionuclide therapy (TRT) has been a promising strategy for cancer therapy, which can inhibit or kill cancer cells by selectively delivering radionuclide to target tissues. Herein, a legumain-targeted therapeutic...

Enhancement of anticancer drug sensitivity in multidrug resistance cells overexpressing ATP-binding cassette (ABC) transporter ABCC10 by CP55, a synthetic derivative of 5-cyano-6-phenylpyrimidin

ATP-binding cassette (ABC) transporter C10 (ABCC10), also named multidrug resistance protein 7 (MRP7), is a member of ABC transporter superfamily and has been revealed to transport a wide range of chemotherapeutic agents including taxanes, epothilone B, Vinca alkaloids, and anthracyclines. In our previous study, a 5-cyano-6-phenylpyrimidin derivative CP55 was synthesized and found significantly reversal effect of multidrug resistance (MDR) mediated by ABCB1. In this study, we found CP55 also efficiently reversed MDR mediated by ABCC10. Our in vitro study showed that co-treatment with CP55 significantly increased the efficacy of ABCC10-substrate anticancer drugs in MDR cells overexpressing ABCC10. Furthermore, we showed that treatment with CP55 increased the intracellular accumulation of [3H]-labeled anticancer drugs and in-turn decreasing drug efflux by inhibiting the transport activity, without altering ABCC10 protein ex-pression level or cellular localization. Potential CP55-ABCC10 interactions were predicted via docking analysis using human ABCC10 homology model and obtained high docking score. Therefore, CP55 represents a promising therapeutic agent in the combinational treatment of chemo-resistant cancer related to ABCC10.

Stimuli-responsive polypeptide nanoassemblies: Recent progress and applications in cancer nanomedicine

Stimuli-responsive polypeptide nanoassemblies exhibit great potentials for cancer nanomedicines because of desirable biocompatibility and biodegradability, unique secondary conformations, varying functionalities, and especially the stimuli-enhanced therapeutic efficacy and reduced side effect. This review introduces the design and fabrication of stimuli-responsive polypeptide nanoassemblies that exhibit endogenous stimuli (e.g., pH, reduction, reactive oxygen species, adenosine triphosphate and enzyme, etc.) and exogenous light stimuli (e.g., UV and near-infrared light), which are biologically related or applied in the clinic. We also discuss the applications and prospects of those stimuli-responsive polypeptide nanoassemblies that might overcome the biological barriers of cancer nanomedicines for in vivo administration. Much more effort is needed to accelerate the second-generation stimuli-responsive polypeptide nanomedicines for clinical transition and applications. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Recent advances in peptide-targeted micelleplexes: Current developments and future perspectives

The decoding of the human genome revolutionized the understanding of how genetics influence the interplay between health and disease, in a multidisciplinary perspective. Thus, the development of exogenous nucleic acids-based therapies has increased to overcome hereditary or acquired genetic-associated diseases. Gene drug delivery using non-viral systems, for instance micelleplexes, have been recognized as promising options for gene-target therapies. Micelleplexes are core-shell structures, at a nanometric scale, designed using amphiphilic block copolymers. These can self-assemble in an aqueous medium, leading to the formation of a hydrophilic and positively charged corona - that can transport nucleic acids, - and a hydrophobic core - which can transport poor water-soluble drugs. However, the performance of these types of carriers usually is hindered by several in vivo barriers. Fortunately, due to a significant amount of research, strategies to overcome these shortcomings emerged. With a wide range of structural features, good stability against proteolytic degradation, affordable characteristic, easy synthesis, low immunogenicity, among other advantages, peptides have increasingly gained popularity as target ligands for non-viral carriers. Hence, this review addresses the use of peptides with micelleplexes illustrating, through the analysis of in vitro and in vivo studies, the potential and future perspectives of this combination.

The Fate of Nanoparticles In Vivo and the Strategy of Designing Stealth Nanoparticle for Drug Delivery

Nano-drug delivery systems (Nano-DDS) offer powerful advantages in drug delivery and targeted therapy for diseases. Compared to the traditional drug formulations, Nano-DDS can increase solubility, biocompatibility, and reduce off-targeted side effects of free drugs. However, they still have some disadvantages that pose a limitation in reaching their full potential in clinical use. Protein adsorption in blood, activation of the complement system, and subsequent sequestration by the mononuclear phagocyte system (MPS) consequently result in nanoparticles (NPs) to be rapidly cleared from circulation. Therefore, NPs have low drug delivery efficiency. So, it is important to develop stealth NPs for reducing bio-nano interaction. In this review, we first conclude the interaction between NPs and biological environments, such as blood proteins and MPS, and factors influencing each other. Next, we will summarize the new strategies to reduce NPs protein adsorption and uptake by the MPS based on current knowledge of the bio-nano interaction. Further directions will also be highlighted for the development of biomimetic stealth nano-delivery systems by combining targeted strategies for a better therapeutic effect.

Dual TTK/CLK2 inhibitor, CC-671, selectively antagonizes ABCG2-mediated multidrug resistance in lung cancer cells

One pivotal factor that leads to multidrug resistance (MDR) is the overexpression of ABCG2. Therefore, tremendous effort has been devoted to the search of effective reversal agents to overcome ABCG2‐mediated MDR. CC‐671 is a potent and selective inhibitor of both TTK (human protein kinase monopolar spindle 1 [hMps1]) and CDC like kinase 2 (CLK2). It represents a new class of cancer therapeutic drugs. In this study, we show that CC‐671 is an effective ABCG2 reversal agent that enhances the efficacy of chemotherapeutic drugs in ABCG2‐overexpressing lung cancer cells. Mechanistic studies show that the reversal effect of CC‐671 is primarily attributed to the inhibition of the drug efflux activity of ABCG2, which leads to an increased intracellular level of chemotherapeutic drugs. In addition, CC‐671 does not alter the protein expression or subcellular localization of ABCG2. The computational molecule docking analysis suggests CC‐671 has high binding affinity to the drug‐binding site of ABCG2. In conclusion, we reveal the interaction between CC‐671 and ABCG2, providing a rationale for the potential combined use of CC‐671 with ABCG2 substrate to overcome MDR.