Efficient Cancer Regression by a Thermosensitive Liposome for Photoacoustic Imaging-Guided Photothermal/Chemo Combinatorial Therapy

Advances in liposomes loaded with photoresponse materials for cancer therapy

Cancer treatment is presently a significant challenge in the medical domain, wherein the primary modalities of intervention include chemotherapy, radiation therapy and surgery. However, these therapeutic modalities carry side effects. Photothermal therapy (PTT) and photodynamic therapy (PDT) have emerged as promising modalities for the treatment of tumors in recent years. Phototherapy is a therapeutic approach that involves the exposure of materials to specific wavelengths of light, which can subsequently be converted into either heat or Reactive Oxygen Species (ROS) to effectively eradicate cancer cells. Due to the hydrophobicity and lack of targeting of many photoresponsive materials, the use of nano-carriers for their transportation has been extensively explored. Among these nanocarriers, liposomes have been identified as an effective drug delivery system due to their controllability and availability in the biomedical field. By binding photoresponsive materials to liposomes, it is possible to reduce the cytotoxicity of the material and regulate drug release and accumulation at the tumor site. This article provides a comprehensive review of the progress made in cancer therapy using photoresponsive materials loaded onto liposomes. Additionally, the article discusses the potential synergistic treatment through the combination of phototherapy with chemo/immuno/gene therapy using liposomes.

Stimuli-responsive (nano)architectures for phytochemical delivery in cancer therapy

The use of phytochemicals for purpose of cancer therapy has been accelerated due to resistance of tumor cells to conventional chemotherapy drugs and therefore, monotherapy does not cause significant improvement in the prognosis and survival of patients. Therefore, administration of natural products alone or in combination with chemotherapy drugs due to various mechanisms of action has been suggested. However, cancer therapy using phytochemicals requires more attention because of poor bioavailability of compounds and lack of specific accumulation at tumor site. Hence, nanocarriers for specific delivery of phytochemicals in tumor therapy has been suggested. The pharmacokinetic profile of natural products and their therapeutic indices can be improved. The nanocarriers can improve potential of natural products in crossing over BBB and also, promote internalization in cancer cells through endocytosis. Moreover, (nano)platforms can deliver both natural and synthetic anti-cancer drugs in combination cancer therapy. The surface functionalization of nanostructures with ligands improves ability in internalization in tumor cells and improving cytotoxicity of natural compounds. Interestingly, stimuli-responsive nanostructures that respond to endogenous and exogenous stimuli have been employed for delivery of natural compounds in cancer therapy. The decrease in pH in tumor microenvironment causes degradation of bonds in nanostructures to release cargo and when changes in GSH levels occur, it also mediates drug release from nanocarriers. Moreover, enzymes in the tumor microenvironment such as MMP-2 can mediate drug release from nanocarriers and more progresses in targeted drug delivery obtained by application of nanoparticles that are responsive to exogenous stimulus including light.

Design strategy and research progress of multifunctional nanoparticles in lung cancer therapy

INTRODUCTION

Lung cancer is one of the cancer types with the highest mortality rate, exploring a more effective treatment modality that improves therapeutic efficacy while mitigating side effects is now an urgent requirement. Designing multifunctional nanoparticles can be used to overcome the limitations of drugs and conventional drug delivery systems. Nanotechnology has been widely researched, and through different needs, suitable nanocarriers can be selected to load anti-cancer drugs to improve the therapeutic effect. It is foreseeable that with the rapid development of nanotechnology, more and more lung cancer patients will benefit from nanotechnology. This paper reviews the merits of various multifunctional nanoparticles in the treatment of lung cancer to provide novel ideas for lung cancer treatment.

AREAS COVERED

This review focuses on summarizing various nanoparticles for targeted lung cancer therapy and their advantages and disadvantages, using nanoparticles loaded with anti-cancer drugs, delivered to lung cancer sites, enhancing drug half-life, improving anti-cancer drug efficacy and reducing side effects.

EXPERT OPINION

The delivery mode of nanoparticles with superior pharmacokinetic properties in the in vivo circulation enhances the half-life of the drug, and provides tissue-targeted selectivity and the ability to overcome biological barriers, bringing a revolution in the field of oncology.

pH-responsive upconversion mesoporous silica nanospheres for combined multimodal diagnostic imaging and targeted photodynamic and photothermal cancer therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) have garnered considerable interest as non-invasive cancer treatment modalities. However, these approaches remain limited by low solubility, poor stability and inefficient targeting of many common photosensitizers (PSs) and photothermal agents (PTAs). To overcome these limitations, we have designed biocompatible and biodegradable tumor-targeted upconversion nanospheres with imaging capabilities. The multifunctional nanospheres consist of a sodium yttrium fluoride core doped with lanthanides (ytterbium, erbium and gadolinium) and bismuth selenide (NaYF 4 :Yb/Er/Gd,Bi 2 Se 3 ) within a mesoporous silica shell that encapsulates a PS, Chlorin e6 (Ce6), in its pores. NaYF 4 :Yb/Er converts deeply penetrating near-infrared (NIR) light to visible light, which excites the Ce6 to generate cytotoxic reactive oxygen species (ROS), while the PTA Bi 2 Se 3 efficiently converts absorbed NIR light to heat. Additionally, Gd enables magnetic resonance imaging (MRI) of the nanospheres. The mesoporous silica shell is coated with lipid/polyethylene glycol (DPPC/cholesterol/DSPE-PEG) to ensure retention of the encapsulated Ce6 and minimize interactions with serum proteins and macrophages that impede tumor targeting. Finally, the coat is functionalized with the acidity-triggered rational membrane (ATRAM) peptide, which promotes specific and efficient internalization into cancer cells within the mildly acidic tumor microenvironment. Following uptake by cancer cells in vitro , NIR laser irradiation of the nanospheres caused substantial cytotoxicity due to ROS production and hyperthermia. The nanospheres facilitated tumor MRI and thermal imaging, and exhibited potent NIR laser light-induced antitumor effects in vivo via combined PDT and PTT, with no observable toxicity to healthy tissue, thereby substantially prolonging survival. Our results demonstrate that the ATRAM-functionalized, lipid/PEG-coated upconversion mesoporous silica nanospheres (ALUMSNs) offer multimodal diagnostic imaging and targeted combinatorial cancer therapy.

Stimuli-responsive liposomal nanoformulations in cancer therapy: Pre-clinical & clinical approaches

The site-specific delivery of antitumor agents is of importance for providing effective cancer suppression. Poor bioavailability of anticancer compounds and the presence of biological barriers prevent their accumulation in tumor sites. These obstacles can be overcome using liposomal nanostructures. The challenges in cancer chemotherapy and stimuli-responsive nanocarriers are first described in the current review. Then, stimuli-responsive liposomes including pH-, redox-, enzyme-, light-, thermo- and magneto-sensitive nanoparticles are discussed and their potential for delivery of anticancer drugs is emphasized. The pH- or redox-sensitive liposomes are based on internal stimulus and release drug in response to a mildly acidic pH and GSH, respectively. The pH-sensitive liposomes can mediate endosomal escape via proton sponge. The multifunctional liposomes responsive to both redox and pH have more capacity in drug release at tumor site compared to pH- or redox-sensitive alone. The magnetic field and NIR irradiation can be exploited for external stimulation of liposomes. The light-responsive liposomes release drugs when they are exposed to irradiation; thermosensitive-liposomes release drugs at a temperature of >40 °C when there is hyperthermia; magneto-responsive liposomes release drugs in presence of magnetic field. These smart nanoliposomes also mediate co-delivery of drugs and genes in synergistic cancer therapy. Due to lack of long-term toxicity of liposomes, they can be utilized in near future for treatment of cancer patients.

Listening to drug delivery and responses via photoacoustic imaging

Administrating pharmaceutic agents efficiently to achieve the therapeutic effect is the aim of all drug delivery techniques. Recent drug delivery systems aim to deliver high doses of drugs to disease sites accurately while maximizing therapeutic effects and minimizing potential side effects. Key approaches apply image guidance techniques for the quantification of drug biodistribution and pharmacokinetic parameters during drug delivery. This review highlights recent research on image-guided drug delivery systems based on photoacoustic imaging, which has been attracting attention for its non-invasiveness, non-ionizing radiation, and real-time imaging functions. Photoacoustic imaging based on the photothermal conversion efficiency of agents can be easily combined with various phototherapeutics, making them highly suitable for drug delivery therapy platforms. Here, we summarize and compare the characteristics of various types of photoacoustic imaging systems, focus on contrast-enhanced photoacoustic imaging and controlled release of therapeutics in drug delivery systems for synergistic therapies.

Co-delivery of nanoparticle and molecular drug by hollow mesoporous organosilica for tumor-activated and photothermal-augmented chemotherapy of breast cancer

BACKGROUND

In comparison with traditional therapeutics, it is highly preferable to develop a combinatorial therapeutic modality for nanomedicine and photothermal hyperthermia to achieve safe, efficient, and localized delivery of chemotherapeutic drugs into tumor tissues and exert tumor-activated nanotherapy. Biocompatible organic-inorganic hybrid hollow mesoporous organosilica nanoparticles (HMONs) have shown high performance in molecular imaging and drug delivery as compared to other inorganic nanosystems. Disulfiram (DSF), an alcohol-abuse drug, can act as a chemotherapeutic agent according to its recently reported effectiveness for cancer chemotherapy, whose activity strongly depends on copper ions.

RESULTS

In this work, a therapeutic construction with high biosafety and efficiency was proposed and developed for synergistic tumor-activated and photothermal-augmented chemotherapy in breast tumor eradication both in vitro and in vivo. The proposed strategy is based on the employment of HMONs to integrate ultrasmall photothermal CuS particles onto the surface of the organosilica and the molecular drug DSF inside the mesopores and hollow interior. The ultrasmall CuS acted as both photothermal agent under near-infrared (NIR) irradiation for photonic tumor hyperthermia and Cu2+ self-supplier in an acidic tumor microenvironment to activate the nontoxic DSF drug into a highly toxic diethyldithiocarbamate (DTC)-copper complex for enhanced DSF chemotherapy, which effectively achieved a remarkable synergistic in-situ anticancer outcome with minimal side effects.

CONCLUSION

This work provides a representative paradigm on the engineering of combinatorial therapeutic nanomedicine with both exogenous response for photonic tumor ablation and endogenous tumor microenvironment-responsive in-situ toxicity activation of a molecular drug (DSF) for augmented tumor chemotherapy.

Novel Multifunctional Stimuli-Responsive Nanoparticles for Synergetic Chemo-Photothermal Therapy of Tumors

In this study, a novel class of multifunctional responsive nanoparticles is designed and fabricated as drug nanocarriers for synergetic chemo-photothermal therapy of tumors. The proposed nanoparticles are composed of a thermo-/pH-responsive poly(N-isopropylacrylamide-co-acrylic acid) (PNA) nanogel core, a polydopamine (PDA) layer for photothermal conversion, and an outer folic acid (FA) layer as a targeting agent for the folate receptors on tumor cells. The fabricated nanoparticles show good biocompatibility and outstanding photothermal conversion efficiency. The proposed nanoparticles loaded with doxorubicin (DOX) drug molecules are stable under physiological conditions with low leakage of drugs, while rapidly release drugs in environments with low pH conditions and at high temperature. The experimental results show that the drug release process is mainly governed by Fickian diffusion. In vitro cell experimental results demonstrate that the PNA-DOX@PDA-FA nanoparticles can be phagocytized by 4T1 tumor cells and release drugs in tumor cell acidic environments, and confirm that the combined chemo and photothermal therapeutic efficacy of PNA-DOX@PDA-FA nanoparticles is higher than the photothermal therapeutic efficacy or the chemotherapeutic efficacy alone. The proposed multifunctional responsive nanoparticles in this study provide a novel class of drug nanocarriers as a promising tool for synergetic chemo-photothermal therapy of tumors.

Stimuli-responsive polymer-based systems for diagnostic applications

Stimuli-responsive polymers exhibit properties that make them ideal candidates for biosensing and molecular diagnostics. Through rational design of polymer composition combined with new polymer functionalization and synthetic strategies, polymers with myriad responsivities, e.g., responses to temperature, pH, biomolecules, CO2, light, and electricity can be achieved. When these polymers are specifically designed to respond to biomarkers, stimuli-responsive devices/probes, capable of recognizing and transducing analyte signals, can be used to diagnose and treat disease. In this review, we highlight recent state-of-the-art examples of stimuli-responsive polymer-based systems for biosensing and bioimaging.

Endogenous H2S-Activable Liposomal Nanoplatform for Synergistic Colorectal Tumor Ablation at Mild Apparent Temperature

Photoinduced hyperthermia possesses great potential in photothermal therapy and thermal-responsive chemotherapy of tumors. However, traditional thermal-triggered drug release requires high temperature, which results in unpleasant activation of thermal-induced cellular self-protection. In this work, a Cu-complex modified and drug-loaded liposomal nanoplatform was constructed for endogenous H₂S-activated synergistic ablation of colorectal tumors. In response to H₂S, the incorporated Cu-complex contributed to the formation of semiconductor CuS on the surface of the as-designed liposomal nanoplatform, which led to local heating under near-infrared (NIR) laser irradiation to achieve simultaneous photothermal therapy and drug release. It is noteworthy that although the drug release occurred at a mild apparent temperature, it was actually triggered by the high eigen temperature on the surface of the liposomal nanoplatform. Therefore, efficient and synergistic photothermal and chemotherapy was achieved under mild apparent temperatures. This work provides insights into achieving selective and bioactivated photothermal therapy and therefore thermal-controlled drug release without using excessive hyperthermia.

Highly stable semiconducting polymer nanoparticles for multi-responsive chemo/photothermal combined cancer therapy

Rationale: Structural stability and size controllability are critical issues to semiconducting polymer nanoparticles (SPNs), which currently show great potential for theranostic applications.

Methods: Herein, multi-responsive semiconducting polymer semi-interpenetrating nanoparticles (PDPP3T@PNIPAMAA IPNs) with highly stable structure and uniform size have been successfully designed by semi-interpenetrating technique.

Results: It is proposed for the first time that PDPP3T@PNIPAMAA IPNs were prepared with “reinforced concrete” particle structure, which is even resistant to organic solvent such as ethanol and THF. By adjusting the polymerization time, the obtained PDPP3T@PNIPAMAA IPNs exhibit uniform and controllable particle size with extremely low polydispersity index (~0.037) at 1 h of reaction time. The presence of pH/light/GSH multi-responsive semi-interpenetrating network in PDPP3T@PNIPAMAA IPNs dramatically increase their drug loading efficiency (92.64%), which is significantly higher than previously reported comparable SPNs-based drug delivery systems. Additionally, PDPP3T@PNIPAMAA-DOX IPNs further provide improved therapeutic efficacy by the combination of chemotherapy and photothermal therapy with controllably regulated release of doxorubicin (DOX). In vitro and in vivo results indicate that PDPP3T@PNIPAMAA-DOX IPNs are able to release drugs at controlled rate by pH/light/GSH regulation and offer PAI-guided chemo/photothermal combined therapy with excellent therapeutic efficacy.

Conclusions: The semi-interpenetrating network method may be generally extended for the preparation of a wide range of organic polymer nanoparticles to achieve ultrahigh structural stability, precise particle size controllability and excellent drug loading capacity.

Specific Core-Satellite Nanocarriers for Enhanced Intracellular ROS Generation and Synergistic Photodynamic Therapy

The deficiency of reactive oxygen species (ROS) is the main reason for the current poor efficiency of tumor photodynamic therapy (PDT). To solve this problem, a simple light-triggered core-satellite nanoplatform (UPSD@Au) has been developed by loading Au nanoparticles on the surface of mesoporous silica-coated upconversion nanoparticles. Small molecules DC50 (C₁₇H₁₄BrF₂N₃OS) and photosensitizer (silicon phthalocyanine dihydroxide, SPCD) were loaded into the silica shell to improve ROS production. Meanwhile, PDT can be triggered through facile near-infrared laser irradiation given the occurrence of a moderate photothermal transfer process between upconversion nanoparticles and Au. The reasonable increment in temperature induced by Au resulted in the timely release of DC50. The inhibition of copper transfer by DC50 results in reduced ROS scavenging and thus improves light-triggered ROS accumulation. Notably, the expression levels of the human copper-trafficking proteins Atox1 and CCS in cancerous cells exceed those in normal cells, and thus enhanced ROS accumulation effect was achieved in cancerous cells. In vitro and in vivo results demonstrate that the synergism between DC50 and SPCD coloaded in the UPSD@Au nanoplatform increases the efficiency of PDT. The UPSD@Au platform represents an efficient codelivery method for hydrophobic small molecules and improves sensitization to specific cancer therapy.

Peptidic Monodisperse PEG "Comb" as Multifunctional "Add-On" Module for Imaging-Traceable and Thermo-Responsive Theranostics

Monodisperse polyethylene glycols-modified (M-PEGylated) biomaterials exhibit high structural accuracy, biocompatibility, and fine-tunable physicochemical properties. To develop "smart" drug delivery systems in a controllable and convenient manner, a peptidic M-PEG "comb" with fluorinated L-lysine side chains and a fluorescent N-terminal is conveniently prepared as a ¹⁹ F magnetic resonance imaging (¹⁹ F MRI) and fluorescence dual-imaging traceable and thermo-responsive "add-on" module for liposomal theranostics in cancer therapy. The peptidic M-PEG "comb" has high biocompatibility, thermo-responsivity with a sharp lower critical solution temperature, an aggregation-induced emission fluorescence, and high ¹⁹ F MRI sensitivity. As a highly branched amphiphile, it self-assembles and firmly anchors on the doxorubicin-loaded liposomal nanoparticles, which M-PEGylates the liposomes and facilitates the thermo-responsive drug release and drug tracking with dual-imaging technologies. In a rodent xenograft model of human liver cancer HepG2 cells, the M-PEGylated liposomes exhibit long in vivo half time, low toxicity, high tumor accumulation, "hot spot" ¹⁹ F MRI, and therapeutic efficacy. With accurately programmable chemical structure, fine-tunable physicochemical and biological properties to meet the demands of diagnosis, drug delivery, and therapy, the M-PEG "comb" is promising as a versatile "add-on" module for rapid and convenient formulation of various "smart" theranostics.

Sinomenine hydrochloride loaded thermosensitive liposomes combined with microwave hyperthermia for the treatment of rheumatoid arthritis

The conventional medications are still facing a huge challenge for the treatment of rheumatoid arthritis (RA). Thus, looking for an effective therapy of RA has became an urgent issue nowadays. In this study, a novel thermosensitive liposome loaded with sinomenine hydrochloride (SIN-TSL) was developed by a pH gradient method. The SIN-TSL had a mean particle size of around 100 nm, and an high entrapment efficiency and drug loading capacity. The results also suggested that SIN-TSL had a thermosensitive drug release behaviour, with the drug release rate at 43 °C was much faster than the one at 37 °C. The SIN-TSL could be effectively taken up by lipopolysaccharide-activated HUVECs, without any cytotoxicity was observed. In addition, both in vitro and in vivo studies indicated that the SIN-TSL combined with microwave hyperthermia exhibited superior anti-rheumatoid arthritis effect. Overall, these results suggest that SIN-loaded thermosensitive liposomes combined with microwave hyperthermia could provide an optional strategy for alleviating the clinical symptoms of RA.

Recent Advances in Nanomaterials-Based Chemo-Photothermal Combination Therapy for Improving Cancer Treatment

Conventional chemotherapy for cancer treatment is usually compromised by shortcomings such as insufficient therapeutic outcome and undesired side effects. The past decade has witnessed the rapid development of combination therapy by integrating chemotherapy with hyperthermia for enhanced therapeutic efficacy. Near-infrared (NIR) light-mediated photothermal therapy, which has advantages such as great capacity of heat ablation and minimally invasive manner, has emerged as a powerful approach for cancer treatment. A variety of nanomaterials absorbing NIR light to generate heat have been developed to simultaneously act as carriers for chemotherapeutic drugs, contributing as heat trigger for drug release and/or inducing hyperthermia for synergistic effects. This review aims to summarize the recent development of advanced nanomaterials in chemo-photothermal combination therapy, including metal-, carbon-based nanomaterials and particularly organic nanomaterials. The potential challenges and perspectives for the future development of nanomaterials-based chemo-photothermal therapy were also discussed.

Current developments in drug delivery with thermosensitive liposomes

Thermosensitive liposomes (TSLs) have been an important research area in the field of tumor targeted chemotherapy. Since the first TSLs appeared that using 1,2-dipalmitoyl-sn-glyce-ro-3-phosphocholine (DPPC) as the primary liposomal lipid, many studies have been done using this type of liposome from basic and practical aspects. While TSLs composed of DPPC enhance the cargo release near the phase transition temperature, it has been shown that many factors affect their temperature sensitivity. Thus numerous attempts have been undertaken to develop new TSLs for improving their thermal response performance. The main objective of this review is to introduce the development and recent update of innovative TSLs formulations, including combination of radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), magnetic resonance imaging (MRI) and alternating magnetic field (AMF). In addition, various factors affecting the design of TSLs, such as lipid composition, surfactant, size and serum components are also discussed.

Development of organic semiconducting materials for deep-tissue optical imaging, phototherapy and photoactivation

Recent progress in developing organic semiconducting materials (OSMs) for deep-tissue optical imaging, cancer phototherapy and biological photoactivation is summarized.

A Core-Shell Nanoplatform for Synergistic Enhanced Sonodynamic Therapy of Hypoxic Tumor via Cascaded Strategy

Sonodynamic therapy (SDT) always causes tumor hypoxia aggravation which can induce malignant cell proliferation and drug resistance. To overcome these disadvantages, a cascaded drug delivery system (Lipo/HMME/ACF@MnO2 -AS1411) is constructed for synergistic enhanced sonodynamic therapy. First, hematoporphyrin monomethyl ether (HMME) and acriflavine (ACF) are encapsulated in the lipid layers and the inner aqueous cores of the liposomes, respectively. Then the ultrathin manganese dioxide (MnO2 ) nanosheets are coated on the surface of the liposomes by using KMnO4 and polyethylene glycol through "one step reduction and modification" method. Furthermore, the nanoparticles are decorated with tumor-targeting AS1411 aptamer through the phosphate groups on the DNA strand which can bind to Mn sites to obtain Lipo/HMME/ACF@MnO2 -AS1411 delivery system. Herein, HMME can act as a sonosensitizer, and ACF is used to prevent the formation of HIF-1α/HIF-1β dimerization to overcome the negative effects after SDT. The Lipo/HMME/ACF@MnO2 -AS1411 delivery system has multiple functions, including codelivery of HMME and ACF, pH/glutathione/ultrasound triple responses, synergistic cascaded enhancement of SDT, precise tumor-targeting, and magnetic resonance imaging. The in vitro and in vivo results suggest that the Lipo/HMME/ACF@MnO2 -AS1411 delivery system is a promising core-shell nanoplatform for synergistic enhancement of sonodynamic therapy, which can provide a new approach in the related research fields.

Recent progress in the development of near-infrared organic photothermal and photodynamic nanotherapeutics

Phototherapies including photothermal therapy (PTT) and photodynamic therapy (PDT) have gained considerable attention due to their high tumor ablation efficiency, excellent spatial resolution and minimal side effects on normal tissue. In contrast to inorganic nanoparticles, near-infrared (NIR) absorbing organic nanoparticles bypass the issue of metal-ion induced toxicity and thus are generally considered to be more biocompatible. Moreover, with the guidance of different kinds of imaging methods, the efficacy of cancer phototherapy based on organic nanoparticles has shown to be optimizable. In this review, we summarize the synthesis and application of NIR-absorbing organic nanoparticles as phototherapeutic nanoagents for cancer phototherapy. The chemistry, optical properties and therapeutic efficacies of organic nanoparticles are firstly described. Their phototherapy applications are then surveyed in terms of therapeutic modalities, which include PTT, PDT and PTT/PDT combined therapy. Finally, the present challenges and potential of imaging guided PTT/PDT are discussed.

Rational Design of Multifunctional Polymeric Nanoparticles Based on Poly(l-histidine) and d-α-Vitamin E Succinate for Reversing Tumor Multidrug Resistance

A multifunctional nanoparticulate system composed of methoxy poly(ethylene glycol)-poly(l-histidine)-d-α-vitamin E succinate (MPEG-PLH-VES) copolymers for encapsulation of doxorubicin (DOX) was elaborated with the aim of circumventing the multidrug resistance (MDR) in breast cancer treatment. The MPEG-PLH-VES nanoparticles (NPs) were subsequently functionalized with biotin motif for targeted drug delivery. The MPEG-PLH-VES copolymer exerts no obvious effect on the P-gp expression level of MCF-7/ADR but exhibited a significant influence on the loss of mitochondrial membrane potential, the reduction of intracellular ATP level, and the inhibition of P-gp ATPase activity of MCF-7/ADR cells. The constructed MPEG-PLH-VES NPs exhibited an acidic pH-induced increase on particle size in aqueous solution. The DOX-encapsulated MPEG-PLH-VES/biotin-PEG-VES (MPEG-PLH-VES/B) NPs were characterized to possess high drug encapsulation efficiency of approximate 90%, an average particle size of approximately 130 nm, and a pH-responsive drug release profile in acidic milieu. Confocal laser scanning microscopy (CLSM) investigations revealed that the DOX-loaded NPs resulted in an effective delivery of DOX into MCF-/ADR cells and a notable carrier-facilitated escape from endolysosomal entrapment. Pertaining to the in vitro cytotoxicity evaluation, the DOX-loaded MPEG-PLH-VES/B NPs resulted in more pronounced cytotoxicity to MCF-/ADR cells compared with DOX-loaded MPEG-PLH-VES NPs and free DOX solution. In vivo imaging study in MCF-7/ADR tumor-engrafted mice exhibited that the MPEG-PLH-VES/B NPs accumulated at the tumor site more effectively than MPEG-PLH-VES NPs due to the biotin-mediated active targeting effect. In accordance with the in vitro results, DOX-loaded MPEG-PLH-VES/B NPs showed the strongest inhibitory effect against the MCF-7/ADR xenografted tumors with negligible systemic toxicity, as evidenced by the histological analysis and change of body weight. The multifunctional MPEG-PLH-VES/B nanoparticulate system has been demonstrated to provide a promising strategy for efficient delivery of DOX into MCF-7/ADR cancerous cells and reversing MDR.

Diketopyrrolopyrrole-based semiconducting polymer nanoparticles for in vivo second near-infrared window imaging and image-guided tumor surgery

A diketopyrrolopyrrole-based semiconducting polymer nanoparticle (PDFT1032) has been developed as a NIR-II (near infrared window II, 1000-1700 nm) fluorescent probe. It shows high photostability, a favorable absorption peak at 809 nm, a large Stokes shift of 223 nm, outstanding biocompatibility and minimal in vivo toxicity. More importantly, the versatile use of PDFT1032 for several important biomedical applications in the NIR-II window has been demonstrated, including the NIR-II optical imaging of tumors on a subcutaneous osteosarcoma model, assessing the vascular embolization therapy of tumors, and NIR-II image-guided orthotopic tumor surgery and sentinel lymph node biopsy (SLNB) with high spatial and temporal resolution. Overall, excellent biocompatibility, favorable hydrophilicity, and desirable chemical and optical properties make the semiconducting polymer nanoparticle PDFT1032 a highly promising NIR-II imaging probe with the potential to be widely applicable in clinical imaging and the surgical treatment of malignancy.

Fusion genes: A promising tool combating against cancer

The driving roles of fusion genes during tumorigenesis have been recognized for decades, with efficacies demonstrated in clinical diagnosis and targeted therapy. With advances in sequencing technologies and computational biology, a surge in the identification of fusion genes has been witnessed during the past decade. The discovery and presence of splicing based fusions in normal tissues have challenged our canonical conceptions on fusion genes and offered us novel medical opportunities. The specificity of fusion genes to neoplastic tissues and their diverse functionalities during carcinogenesis foster them as promising tools in the battle against cancer. It is time to re-visit and comb through our cutting-edge knowledge on fusion genes to accelerate clinical translation of these internal markers. Urged as such, we are encouraged to categorize fusion events according to mechanisms leading to their generation, oncological consequences and clinical implications, offer insights on fusion occurrence across tumors from the system level, highlight feasible practices in fusion-related pharmaceutical development, and identify understudied yet important niches that may lead future research trend in this field.