A versatile strategy to create an active tumor-targeted chemo-photothermal therapy nanoplatform: A case of an IR-780 derivative co-assembled with camptothecin prodrug

Recent advances of novel targeted drug delivery systems based on natural medicine monomers against hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the most prevalent type of liver cancer, is often diagnosed at an advanced stage. Surgical interventions are often ineffective, leading HCC patients to rely on systemic chemotherapy. Unfortunately, commonly used chemotherapeutic drugs have limited efficacy and can adversely affect vital organs, causing significant physical and psychological distress for patients. Natural medicine monomers (NMMs) have shown promising efficacy and safety profiles in HCC treatment, garnering attention from researchers. In recent years, the development of novel targeted drug delivery systems (TDDS) combining NMMs with nanocarriers has emerged. These TDDS aim to concentrate drugs effectively in HCC cells by manipulating the characteristics of nanomedicines, leveraging receptor and ligand interactions, and utilizing endogenous stimulatory responses to promote specific nanomedicines distribution. This comprehensive review presents recent research on TDDS for HCC treatment using NMMs from three perspectives: passive TDDS, active TDDS, and stimuli-responsive drug delivery systems (SDDS). It consolidates the current state of research on TDDS for HCC treatment with NMMs and highlights the potential of these innovative approaches in improving treatment outcomes. Moreover, the review also identifies research gaps in the related fields to provide references for future targeted therapy research in HCC.

HER2-targeting two-dimensional black phosphorus as a nanoplatform for chemo-photothermal therapy in breast cancer

Trastuzumab (Tmab) targeted therapy or its combination with chemotherapy is normally insufficient to elicit a comprehensive therapeutic response owing to the inherent or acquired drug resistance and systemic toxicity observed in highly invasive HER2-positive breast cancer. In this study, we propose a novel approach that integrates photothermal therapy (PTT) with targeted therapy and chemotherapy, thereby achieving additive or synergistic therapeutic outcomes. We utilize PEGylated two-dimensional black phosphorus (2D BP) as a nanoplatform and photothermal agent to load chemotherapeutic drug mitoxantrone (MTO) and conjugate with Tmab (BP-PEG-MTO-Tmab). The in vitro and in vivo experiments demonstrated that the HER2-targeting BP-PEG-MTO-Tmab complexes exhibited desirable biocompatibility, safety and enhanced cancer cell uptake efficiency, resulting in increased accumulation and prolonged retention of BP and MTO within tumors. Consequently, the complex improved photothermal and chemotherapy treatment efficacy in HER2-positive cells in vitro and a subcutaneous tumor model in vivo, while minimized harm to normal cells and showed desirable organ compatibility. Collectively, our study provides compelling evidence for the remarkable efficacy of targeted and synergistic chemo-photothermal therapy utilizing all-in-one nanoparticles as a delivery system for BP and chemotherapeutic drug in HER2-positive breast cancer.

Camptothecin-based prodrug nanomedicines for cancer therapy

Camptothecin (CPT) is a cytotoxic alkaloid that attenuates the replication of cancer cells via blocking DNA topoisomerase 1. Despite its encouraging and wide-spectrum antitumour activity, its application is significantly restricted owing to its instability, low solubility, significant toxicity, and acquired tumour cell resistance. This has resulted in the development of many CPT-based therapeutic agents, especially CPT-based nanomedicines, with improved pharmacokinetic and pharmacodynamic profiles. Specifically, smart CPT-based prodrug nanomedicines with stimuli-responsive release capacity have been extensively explored owing to the advantages such as high drug loading, improved stability, and decreased potential toxicity caused by the carrier materials in comparison with normal nanodrugs and traditional delivery systems. In this review, the potential strategies and applications of CPT-based nanoprodrugs for enhanced CPT delivery toward cancer cells are summarized. We appraise in detail the chemical structures and release mechanisms of these nanoprodrugs and guide materials chemists to develop more powerful nanomedicines that have real clinical therapeutic capacities.

The recent developments of camptothecin and its derivatives as potential anti-tumor agents

This review article focuses on the research progress made in the structural modifications of camptothecin (CPT), a potent cytotoxic natural alkaloid. CPT possesses a unique 5-fused ring structure and exhibits various beneficial activities such as anti-proliferative, anti-fungal, insecticidal, and anti-SARS-CoV-2 properties. CPT and its analogs, including Topotecan and Irinotecan, have been successfully developed and marketed as topoisomerase I inhibitors. To enhance the therapeutic potential of CPT, researchers have undertaken structural modifications primarily on the A, B, and E rings of the CPT core structure. These modifications aim to improve the efficacy, selectivity, and pharmacokinetic properties of CPT derivatives. The article reviews the advancements in hybridizing CPT with other bioactive compounds, the synthesis of novel CPT analogs, and their associated biological activities. Moreover, the structure-activity relationship (SAR) of these modified CPT derivatives is summarized to gain insights into their structure-function correlations. In addition to discussing the modifications and biological activities of CPT derivatives, the article also touches upon the mechanism of parent drug release. Many CPT derivatives are prodrugs, meaning they require metabolic activation to generate the active form of the drug. It is a resource for researchers interested in developing novel anti-tumor agents based on CPT, addressing the limitations associated with the parent drug, and exploring various aspects of CPT modifications.

Hyaluronic Acid-Conjugated Fluorescent Probe-Shielded Polydopamine Nanomedicines for Targeted Imaging and Chemotherapy of Bladder Cancer

Bladder cancer is one of the most common malignancies in the urinary system, with high risk of recurrence and progression. However, the difficulty in detecting small tumor lesions and the lack of selectivity of intravesical treatment seriously affect the prognosis of patients with bladder cancer. In the present work, a nanoparticle-based delivery system with tumor targeting, high biocompatibility, simple preparation, and the ability to synergize imaging and therapy was fabricated. Specifically, this nanosystem consisted of the core of doxorubicin (DOX)-loaded polydopamine nanoparticles (PDD NPs) and the shell of hyaluronic acid (HA)-conjugated IR780 (HA-IR780). The HA-IR780-covered PDD NPs (HR-PDD NPs) demonstrated tumor targeting and visualization both in vitro and in vivo with properties of promoted cancer cell endocytosis and lysosomal escape, efficiently delivering drugs to the target site and exerting a killing effect on tumor cells. Encouragingly, intravesical instillation of HR-PDD NPs improved drug retention in the bladder and promoted its accumulation in tumor tissue, resulting in better tumor proliferation inhibition and apoptosis in an orthotopic bladder cancer model in rats. This study provides a promising strategy for the diagnosis and therapy of bladder cancer.

Recent progress on near-infrared fluorescence heptamethine cyanine dye-based molecules and nanoparticles for tumor imaging and treatment

Recenly, near-infrared fluorescence heptamethine cyanine dyes have shown satisfactory values in bioengineering, biology, and pharmacy especially in cancer diagnosis and treatment, owing to their excellent fluorescence property and biocompatibility. In order to achieve broad application prospects, diverse structures, and chemical properties of heptamethine cyanine dyes have been designed to develop novel functional molecules and nanoparticles over the past decade. For fluorescence and photoacoustic tumor imaging properties, heptamethine cyanine dyes are equipped with good photothermal performance and reactive oxygen species production properties under near-infrared light irradiation, thus holding great promise in photodynamic and/or photothermal cancer therapies. This review offers a comprehensive scope of the structures, comparisons, and applications of heptamethine cyanine dyes-based molecules as well as nanoparticles in tumor treatment and imaging in current years. Therefore, this review may drive the development and innovation of heptamethine cyanine dyes, significantly offering opportunities for improving tumor imaging and treatment in a precise noninvasive manner. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Light-initiated aggregation of gold nanoparticles for synergistic chemo-photothermal tumor therapy

The combination of chemotherapy with photothermal therapy (PTT) has attracted extensive attention due to its excellent synergetic effect attributing to the fact that hyperthermia can effectively promote the tumor uptake of chemotherapeutic drugs. Herein, we propose a light-initiated gold nanoparticle (AuNP) aggregation boosting the uptake of chemotherapeutic drugs for enhanced chemo-photothermal tumor therapy. Novel light-responsive AuNPs (tm-AuNPs) were rationally designed and fabricated by conjugating both 2,5-diphenyltetrazole (Tz) and methacrylic acid (Ma) onto the surface of AuNPs with small size (∼20 nm). Upon the irradiation of 405 nm laser, AuNPs could be initiated to form aggregates specifically within tumors through the covalent cycloaddition reaction between Tz and Ma. Taking advantage of the controllable photothermal effect of Au aggregates under NIR excitation, improved enrichment of doxorubicin (DOX) in tumor tissues was realized, combined with PTT, resulting in outstanding synergetic anti-tumor efficacy in living mice. We thus believe that this light-initiated AuNP aggregation approach would offer a valuable and powerful tool for precisely synergistic chemo-photothermal tumor therapy.

Multicomponent carrier-free nanodrugs for cancer treatment

Nanocarriers can be used to deliver insoluble anticancer drugs to optimize therapeutic efficacy. However, the potential toxicity of nanocarriers cannot be ignored. Carrier-free nanodrugs are emerging safe drug delivery systems, which are composed of multiple components, such as drugs, bioactive molecules and functional ingredients, avoiding the usage of inert carrier materials and offering advantages that include high drug loading, low toxicity, synergistic therapy, versatile design, and easy surface functionalization. Therefore, how to design multicomponent carrier-free nanodrugs is becoming a priority. In this review, the common strategies for rapid construction of multicomponent carrier-free nanodrugs are briefly explored from the perspective of methodology. The properties of organic-organic, organic-inorganic and inorganic-inorganic multiple carrier-free nanosystems are analyzed according to wettability and in-depth understanding is provided. Further advances in the applications of multiple carrier-free nanodrugs are outlined in anticipation of grasping the intrinsic nature for the design and development of carrier-free nanodrugs.

Tailoring carrier-free nanocombo of small-molecule prodrug for combinational cancer therapy

The outcomes of monotherapy could not satisfy clinical cancer treatment owing to the challenges of tumor heterogeneity, multi-drug resistance, tumor metastasis and relapse. In response, the significance of combinational cancer therapy has been highlighted. Traditional combinational schemes usually utilize "free" drug for multi drug administration, independently. The diverse pharmacokinetics and biodistribution greatly hinder the antitumor effects and cause systematic toxicity. To tackle the hinderance, various nanoparticulate drug delivery systems (Nano-DDSs) have been developed. However, conventional Nano-DDSs encapsulate drugs into carrier materials through noncovalent interactions, resulting in low drug loading, fixed multi drug encapsulation ratio, chemical instability and carrier-associated toxicity. Recently, carrier-free nanocombos based on self-assembling small-molecule prodrugs (SPNCs) have emerged as a versatile Nano-DDSs for multiple drug delivery. Benefited by the self-assembly capability, SPNCs could be facilely fabricated with distinct merits of ultra-high drug loading, adjustable drug ratio and negligible carrier-associated toxicity. Herein, we summarize the latest trends of SPNCs. First, a basic review on self-assembling small-molecule prodrugs is presented. Additionally, facile techniques to prepare SPNCs are introduced. Furthermore, advanced combinational therapies based on SPNCs are spotlighted with special emphasis on synergistic mechanisms. Finally, future prospects and challenges are discussed.

NIR/MRI-Guided Oxygen-Independent Carrier-Free Anti-Tumor Nano-Theranostics

Imaging-guided photothermal therapy (PTT)/photodynamic therapy (PDT) for cancer treatment are beneficial for precise localization of the malignant lesions and combination of multiple cell killing mechanisms in eradicating stubborn thermal-resistant cancer cells. However, overcoming the adverse impact of tumor hypoxia on PDT efficacy remains a challenge. Here, carrier-free nano-theranostic agents are developed (AIBME@IR780-APM NPs) for magnetic resonance imaging (MRI)-guided synergistic PTT/thermodynamic therapy (TDT). Two IR780 derivatives are synthesized as the subject of nanomedicine to confer the advantages for the nanomedicine, which are by feat of amphiphilic IR780-PEG to enhance the sterical stability and reduce the risk from reticuloendothelial system uptake, and IR780-ATU to chelate Mn²⁺ for T₁ -weighted MRI. Dimethyl 2,2'-azobis(2-methylpropionate) (AIBME), acting as thermally decomposable radical initiators, are further introduced into nanosystems with the purpose of generating highly cytotoxic alkyl radicals upon PTT launched by IR780 under 808 nm laser irradiation. Therefore, the sequentially generated heat and alkyl radicals synergistically induce cell death via synergistic PTT/TDT, ignoring tumor hypoxia. Moreover, these carrier-free nano-theranostic agents present satisfactory biocompatibility, which could be employed as a powerful weapon to hit hypoxic tumors via MRI-guided oxygen-independent PTT and photonic TDT.

Poly-l-lysine derivative-coated black phosphorus as a nanoplatform for photothermal chemotherapy to enhance anti-tumor efficiency

Severe systemic toxicity and side effects are major obstacles to the success of chemotherapy for tumors. Regardless of the choice of chemotherapy drugs, the safety of drug delivery materials is crucial, and therefore, there have been various efforts to improve the therapeutic effect and the biological safety of drug delivery systems (DDSs). In this study, a dual stimulus-response DDS (PLL-SS@DOX-BP) was constructed based on the biomaterials of black phosphorus (BP) nanosheets and poly-l-lysine (PLL) to enhance the treatment of doxorubicin hydrochloride (DOX) for breast cancer. The PLL derivative was nano-coated on the surface of drug-loaded BP nanosheets, and it prevented premature leakage of the drug and maintained the stability of the DDS. The introduced disulfide bonds and photothermal agent BP enabled the redox and near-infrared responsive drug release of the DDS, and the coated PLL derivative on the nanocarrier decreased premature leakage of the drug before the DDS reached the tumor tissues. The in vitro and in vivo experiments showed that the combination of biomaterial (PLL) and photothermal material (BP nanosheets) exhibited excellent biological safety and remarkable drug delivery capacity. Moreover, the pharmacodynamic studies indicated that PLL-SS@DOX-BP is a powerful vehicle for photothermal therapy in combination with chemotherapy. Compared with chemotherapy alone, the developed DDS displayed enhanced anti-tumor efficiency with decreased systemic toxicity, and thus, it has the potential to be a promising anti-tumor treatment strategy.

Injectable and Temperature-Sensitive Titanium Carbide-Loaded Hydrogel System for Photothermal Therapy of Breast Cancer

Recently, organic–inorganic hybrid materials have gained much attention as effective photothermal agents for cancer treatment. In this study, Pluronic F127 hydrogel-coated titanium carbide (Ti₃C₂) nanoparticles were utilized as an injectable photothermal agent. The advantages of these nanoparticles are their green synthesis and excellent photothermal efficiency. In this system, lasers were mainly used to irradiate Ti₃C₂ nanoparticles to produce a constant high temperature, which damaged cancer cells. The nanoparticles were found to be stable during storage at low temperatures for at least 2 weeks. The Ti₃C₂ nanoparticles exhibited a shuttle-shaped structure, and the hydrogels presented a loosely meshed structure. In addition, Ti₃C₂ nanoparticles did not affect the reversible temperature sensitivity of the gel, and the hydrogel did not affect the photothermal properties of Ti₃C₂ nanoparticles. The in vitro and in vivo results show that this hydrogel system can effectively inhibit tumor growth upon exposure to near-infrared irradiation with excellent biocompatibility and biosafety. The photothermal agent-embedded hydrogel is a promising photothermal therapeutic strategy for cancer treatment by enhancing the retention in vivo and elevating the local temperature in tumors.

A disulfide-induced supra-amphiphilic co-assembly for glycosylated pro-drug-photosensitizer nanoparticles in combination therapies

We reported an intermolecular chalcogen bonding interaction (S⋯S contacts) induced supra-amphiphilic co-assembly strategy to construct glycosylated pro-drug-photosensitizer nanoparticles (BG-L NPs) in combination therapies.

Small-Molecule Prodrug Nanoassemblies: An Emerging Nanoplatform for Anticancer Drug Delivery

The antitumor efficiency and clinical translation of traditional nanomedicines is mainly restricted by low drug loading, complex preparation technology, and potential toxicity caused by the overused carrier materials. In recent decades, small-molecule prodrug nanoassemblies (SMP-NAs), which are formed by the self-assembly of prodrugs themselves, have been widely investigated with distinct advantages of ultrahigh drug-loading and negligible excipients-trigged adverse reaction. Benefited from the simple preparation process, SMP-NAs are widely used for chemotherapy, phototherapy, immunotherapy, and tumor diagnosis. In addition, combination therapy based on the accurate co-delivery behavior of SMP-NAs can effectively address the challenges of tumor heterogeneity and multidrug resistance. Recent trends in SMP-NAs are outlined, and the corresponding self-assembly mechanisms are discussed in detail. Besides, the smart stimuli-responsive SMP-NAs and the combination therapy based on SMP-NAs are summarized, with special emphasis on the structure-function relationships. Finally, the outlooks and potential challenges of SMP-NAs in cancer therapy are highlighted.

An MRI-guided targeting dual-responsive drug delivery system for liver cancer therapy

The targeting dual-responsive drug delivery system was employed for cancer treatment as a positive strategy. Herein, Lactobionic acid (LA)-modified and non-modified UV/reduction dual-responsive molecules (10,10-NB-S-S-P-LA and 10,10-NB-S-S-P-OMe) were synthesized. Functional magnetic resonance imaging (MRI) contrast agent (12,12-NB-DTPA-Gd) was mixed with 10,10-NB-S-S-P-LA or 10,10-NB-S-S-P-OMe in the optimal ratio (3:1) to develop targeted empty liposomes (GNSPL) or non-targeted empty liposomes (GNSPM) with superior UV/reduction dual-responsiveness, biocompatibility and magnetic resonance imaging (MRI) performance. The drug-loaded liposomes (GNSPLD and GNSPMD) can keep stable in two weeks, and the drug cumulative release rate reached to the maximum under dual stimulation of ultraviolet (UV) and reducing agent (TCEP). The treatment with GNSPLD + UV significantly inhibited the growth and migration of cancer cells in vitro. The GNSPLD liposomes were more effectively accumulated in tumor site than GNSPMD liposomes, due to the targeting property of GNSPLD liposomes. The treatment with GNSPLD + UV showed a better therapeutic efficacy than Doxorubicin (DOX) in vivo, and almost no side effects during the treatment period. Thus, the MRI-guided targeting dual-responsive drug delivery system provided a reliable therapeutic strategy for treating liver cancer.

IR780-based nanomaterials for cancer imaging and therapy

IR780, a small molecule with a strong optical property and excellent photoconversion efficiency following near infrared (NIR) irradiation, has attracted increasing attention in the field of cancer treatment and imaging. This review is focused on different IR780-based nanoplatforms and the application of IR780-based nanomaterials for cancer bioimaging and therapy. Thus, this review summarizes the overall aspects of IR780-based nanomaterials that positively impact cancer biomedical applications.

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.

Preparation of ROS active and photothermal responsive hydroxyapatite nanoplatforms for anticancer therapy

Photothermal responsive nanoplatforms are attracting for photothermal therapy (PTT) of cancer. Herein, we propose a strategy to prepare IR-780 modified hydroxyapatite (HAP) nanorods as photothermic agents (HAP@IR-780). The results demonstrated that the obtained HAP@IR-780 was photothermal responsive under near-infrared laser irradiation the photothermal conversion efficiency was 69.3%, and it remained photostability after 4 cycles of irradiation. This advantage overcomes the optical instability of IR780. MTT and cellular uptake research proved that HAP@IR-780 was biocompatible in appropriate concentration range (0-20 μg/mL) without laser irradiation. Concentration-dependent internalization and reactive oxygen species (ROS) related apoptosis of HAP@IR-780 for MCF-7 cells were observed. Animal experiments showed that the gathered HAP@IR-780 at the tumor site reached a photothermal responsive temperature up to 57.9 °C, which could almost ablate the tumor with volumes as large as 1500 mm³. In general, our photothermal material has good photothermal conversion characteristics, and may have the least safety problems while showing excellent therapeutic effects. Therefore, HAP@IR-780 has a brilliant prospect in the field of tumor photothermal therapy.

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.

Prototypic Heptamethine Cyanine Incorporating Nanomaterials for Cancer Phototheragnostic

Developing technologies that allow the simultaneous diagnosis and treatment of cancer (theragnostic) has been the quest of numerous interdisciplinary research teams. In this context, nanomaterials incorporating prototypic near infrared (NIR)-light responsive heptamethine cyanines have been showing very promising results for cancer theragnostic. The precisely engineered features of these nanomaterials endow them with the ability to achieve a high tumor accumulation, enabling a tumor's visualization by NIR fluorescence and photoacoustic imaging modalities. Upon interaction with NIR light, the tumor-homed heptamethine cyanine-incorporating nanomaterials can also produce a photothermal/photodynamic effect with a high spatio-temporal resolution and minimal side effects, leading to an improved therapeutic outcome. This progress report analyses the application of nanomaterials incorporating prototypic NIR-light responsive heptamethine cyanines (IR775, IR780, IR783, IR797, IR806, IR808, IR820, IR825, IRDye 800CW, and Cypate) for cancer photothermal therapy, photodynamic therapy, and imaging. Overall, the continuous development of nanomaterials incorporating the prototypic NIR absorbing heptamethine cyanines will cement their phototheragnostic capabilities.

Redox-sensitive lipophilic prodrugs: delivering unstable chemotherapeutant for improved cancer therapy

Therapeutic application of unmodified camptothecin (CPT) is severely restricted by its extremely low water solubility and the instability of active lactone ring. In this study, a redox-sensitive CPT-OA conjugate containing the disulfide bond (CPT-SS-OA) was used to deliver the lactone-stabilized CPT for the improved antitumor efficacy. A non-sensitive CPT-OA was used as control to illuminate the role of disulfide bond. Both CPT-SS-OA and CPT-OA formulated in cremophor EL micelles (CM) displayed multiple therapeutic advantages: small diameter (∼14 nm), efficient cellular internalization, prolonged blood circulation, and favorable biodistribution. However, only CPT-SS-OA/CM achieved the superior chemotherapeutic efficacy over CPT solution in the Lewis lung carcinoma (LLC) cancer xenograft, which was ascribed to the accelerated release of the active lactone CPT responding to the elevated reductive glutathione in tumor cells. Such redox-sensitive lipophilic prodrugs represent an effective alternative strategy for the delivery of CPT in the active lactone form. This strategy can be used for other chemically unstable chemotherapeutant for the improved therapeutic efficacies.

Redox-sensitive dimeric camptothecin phosphatidylcholines-based liposomes for improved anticancer efficacy

Aim: A redox-triggered camptothecin (CPT) liposomal system was developed for an improved clinical potential in tumor therapy. Materials & methods: CPT–phosphorylcholine conjugates (CPT–SS–GPCs: CPT–SS–3–GPC and CPT–SS–11–GPC) were synthesized by conjugating CPT to glycerylphosphorylcholine via disulfide bond linker. CPT–SS–GPCs could be assembled into liposomes. Different in vitro and in vivo analyses were used to evaluate the anticancer activities of CPT–SS–GPCs. Results: CPT–SS–GPCs liposomes exhibited extremely high drug loading and uniform size of 150–200 nm. Moreover, the rapid release of parent CPT in reductive condition and high cellular uptake of CPT–SS–GPCs liposomes were observed. At last, in vitro and in vivo anticancer assay showed the enhanced efficacy of CPT–SS–GPCs liposomes. Conclusion: Redox-triggered CPT–SS–GPC liposomes have great potential in tumor therapy.

Prodrugs in combination with nanocarriers as a strategy for promoting antitumoral efficiency

Prodrug entrapment into nanocarriers for tumor delivery is a strategy to achieve a valid therapy with high efficiency. The prodrug contains anticancer agents conjugating with functional moieties or ligands so that the active component is released after metabolism in the body or tumor. The advantages of nanosystems for loading prodrugs include high loading, increased prodrug stability, improved bioavailability and enhanced targeting to tumor cells. In the present article, we introduce the prodrug delivery approaches according to nanomedicine and the recent advances in prodrug-loaded nanocarriers. First, we discuss the conceptional design of combined prodrugs and nanocarriers in response to the obstruction in anticancer therapy. Then we describe the cases of prodrug-loaded nanoparticles for cancer treatment during the past 5 years.