A Smart Multifunctional Nanoparticle for Enhanced Near-Infrared Image-Guided Photothermal Therapy Against Gastric Cancer

Fabrication of folic acid-modified bovine serum albumin cloaked dual-drug loaded hollow mesoporous silica nanoparticles for pH-responsive and targeted delivery of gastric cancer therapy

Combination therapy is a highly successful way to address the limitations of using a single treatment method and improve therapy's overall efficacy. In this study, we developed a unique hollow mesoporous silica nanoparticle (HMSN) coated with folic acid (FA)-modified bovine serum albumin (FA-BSA). This nanoparticle, referred to as HFB, was designed to target cancer cells and release dual therapeutic drugs, Indocyanine green (ICG) and Paclitaxel (PTX), in response to specific stimuli termed as HFB@IP. The BSA protein acts as a "gatekeeper" to prevent early drug releases and cargo leakage by detaching from BSA in reaction to GSH. The FA facilitates the targeted transport of the drug into cancer cells that express folate receptors (FR), enhancing the effectiveness of chemo-photodynamic treatment (PDT). The drug nanocarrier demonstrated in vitro pH/redox-triggered drug release from HFB@IP due to breaking the imine bonds between aldehyde-functionalized HMSN (CHO-HMSN) and FA-BSA with the disulfide bond inside BSA. In addition, various biological assessments, including cell uptake experiments, demonstrated that HFB@IP effectively targets SGC-7901 cells and induces apoptosis in vitro. Further, it exhibits remarkable efficiency in synergistically killing cancer cells through chemo-photodynamic therapy, as indicated by a combination index (CI) of 0.328. The results showed that combining HMSN with biodegradable stimuli-responsive BSA molecules could offer a promising approach for precise chemo-photodynamic therapy in treating gastric cancer, allowing for the controlled release of drugs as necessary.

Targeted cancer treatment using folate-conjugated sponge-like ZIF-8 nanoparticles: a review

ZIF-8 (zeolitic imidazolate framework-8) is a potential drug delivery system because of its unique properties, which include a large surface area, a large pore capacity, a large loading capacity, and outstanding stability under physiological conditions. ZIF-8 nanoparticles may be readily functionalized with targeting ligands for the identification and absorption of particular cancer cells, enhancing the efficacy of chemotherapeutic medicines and reducing adverse effects. ZIF-8 is also pH-responsive, allowing medication release in the acidic milieu of cancer cells. Because of its tunable structure, it can be easily functionalized to design cancer-specific targeted medicines. The delivery of ZIF-8 to cancer cells can be facilitated by folic acid-conjugation. Hence, it can bind to overexpressed folate receptors on the surface of cancer cells, which holds the promise of reducing unwanted deliveries. As a result of its importance in cancer treatment, the folate-conjugated ZIF-8 was the major focus of this review.

Photothermal Carbon Dots Chelated Hydroxyapatite Filler: High Photothermal Conversion Efficiency and Enhancing Adhesion of Hydrogel

The synthesis of photothermal carbon/hydroxyapatite composites poses challenges due to the binding modes and relatively low photothermal conversion efficiency. To address these challenges, the calcium ions chelated by photothermal carbon dots (PTC-CDs) served as the calcium source for the synthesis of photothermal carbon dots chelated hydroxyapatite (PTC-HA) filler via the coprecipitation method. The coordination constant K and chelation sites of PTC-HA were 7.20 × 102 and 1.61, respectively. Compared to PTC-CDs, the coordination constant K and chelation sites of PTC-HA decreased by 88 and 35% due to chelating to hydroxyapatite, respectively. PTC-HA possesses fluorescence and photothermal performance with a 62.4% photothermal conversion efficiency. The incorporation of PTC-HA filler significantly enhances as high as 76% the adhesion performance of the adhesive hydrogel. PTC-HA with high photothermal conversion efficiency and enhancing adhesion performance holds promise for applications in high photothermal conversion efficiency, offering tissue adhesive properties and fluorescence capabilities to the hydrogel.

Network pharmacology-based strategy for predicting therapy targets of Ecliptae Herba on breast cancer

Breast cancer is a prevalent malignancy affecting women globally, characterized by significant morbidity and mortality rates. Ecliptae Herba is a traditional herbal medicine commonly used in clinical practice, has recently been found to possess antitumor properties. In order to explore the underlying material basis and molecular mechanisms responsible for the anti-breast cancer effects of Ecliptae Herba, we used network pharmacology and experimental verification. UPLC-MS/MS was utilized to identify compounds present in Ecliptae Herba. The active components of Ecliptae Herba and its breast cancer targets were screened using public databases. Hub genes were identified using the STRING and Metascape database. The R software was utilized for visual analysis of GO and KEGG pathways. The affinity of the hub targets for the active ingredients was assessed by molecular docking analysis, which was verified by experimental assessment. A total of 178 targets were obtained from the 10 active components of Ecliptae Herba, while 3431 targets associated with breast cancer were screened. There were 144 intersecting targets between the components and the disease. Targets with a higher degree, namely EGFR and TGFB1, were identified through the hub subnetwork of PPI. GO and KEGG analyses revealed that Ecliptae Herba plays an important role in multiple cancer therapeutic mechanisms. Moreover, molecular docking results showed that the core components had good binding affinity with key targets. Finally, it was confirmed that TGF-β1 might be a potential crucial target of Ecliptae Herba in the treatment of breast cancer by cytological experiments, and the TGF-β1/Smad signaling pathway might be an important pathway for Ecliptae Herba to exert its therapeutic effects. This study elucidated the active ingredients, key targets, and molecular mechanisms of Ecliptae Herba in the treatment of breast cancer, providing a scientific foundation and therapeutic mechanism for the prevention and treatment of breast cancer with Traditional Chinese medicine.

In vivo near-infrared fluorescence imaging of gastric cancer in an MKN-45 gastric cancer xenograft mouse model using intraoperative ureteral identification agent ASP5354

Accurate intraoperative identification of gastric cancer lesions and determination of the extent of resection are important for curability and function preservation. This study aimed to investigate the potential of the near-infrared fluorescence (NIRF) imaging agent ASP5354 for in vivo fluorescence imaging of gastric cancer. The capability of ASP5354 was evaluated using an MKN-45 human gastric cancer xenograft mouse model. A single dose of ASP5354 was intravenously administered to the mice at a concentration of 120 nmol (0.37 mg)/kg body weight. In vivo NIRF images of the mouse backs were obtained using an NIRF camera system. Moreover, the cancer tissues were dissected, and the NIRF intensity in the tissue sections was measured using the NIRF camera system. ASP5354 uptake in MKN-45 cells was assessed in vitro using the NIRF microscope. The NIRF signal of ASP5354 was selectively detected in gastric cancer tissues immediately after the intravenous administration of ASP5354. The cancer tissues emitted stronger NIRF signals than adjacent normal tissues. The difference in the NIRF intensity between the normal and cancer tissues was clearly observed at the boundary between them in the macrolevel NIRF images. Cancer tissues can be distinguished from normal tissues based on the measurement of the NIRF of ASP5354, using an NIRF camera system. ASP5354 is a promising agent for NIRF imaging of gastric cancer tissues.

In Vivo Anchoring Bis-Pyrene Probe for Molecular Imaging of Early Gastric Cancer by Endoscopic Techniques

With the development of blue laser endoscopy (BLE) technique, it's often used to diagnose early gastric cancer (EGC) by the morphological changes of blood vessels through BLE. However, EGC is still not obvious to identify, resulting in a high rate of missed diagnosis. Molecular imaging can show the changes in early tumors at molecular level, which provides a possibility for diagnosing EGC. Therefore, developing a probe that visually monitors blood vessels of EGC under BLE is particularly necessary. Herein, a bis-pyrene (BP) based nanoprobe (BP-FFVLK-(PEG)-RGD, M₁ ) is designed, which can target angiogenesis and self-assemble into fibers in situ, resulting in stable and long-term retention in tumor. Moreover, M₁ probe can emit yellow-green fluorescence for imaging under BLE. M₁ probe is confirmed to steadily remain in tumor for up to 96 hours in mice transplanted subcutaneously. In addition, the M₁ probe is able to target angiogenesis for molecular imaging of isolated human gastric cancer tissue under BLE. Finally, M₁ probe i.v. injected into primary gastric cancer model rabbits successfully highlighted the tumor site under BLE, which is confirmed by pathological analysis. It's the first time to develop a probe for diagnosing EGC by visualizing angiogenesis under BLE, showing great clinical significance.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

ROS-responsive Galactosylated-nanoparticles with Doxorubicin Entrapment for Triple Negative Breast Cancer Therapy

Background

Triple negative breast cancer (TNBC) is one of the most aggressive tumors with high metastasis and mortality, which constitutes 15~20% of all breast cancers. Chemotherapy remains main therapeutic option in the treatment of patients with TNBC.

Methods

We developed reactive oxygen species (ROS)-responsive galactosylated nanoparticles (DOX@NPs) as an efficiently targeted carrier for doxorubicin (DOX) delivery to inhibit the growth of TNBC in vitro and in vivo. DOX@NPs were composed of polyacrylate galactose and phenylboronic derivatives conjugation. The in vitro cytotoxicity, cellular uptake, cell apoptosis and cycle distribution of tumor cells treated with different formulations were investigated. Meanwhile in vivo biodistribution and antitumor effects were investigated in a 4T1 tumor-bearing mouse model.

Results

DOX@NPs showed good ROS responsiveness and rapid DOX release in the presence of H₂O₂. Furthermore, our data suggested that DOX@NPs could effectively trigger tumor cells apoptosis and cycle arrest, efficiently accumulate into tumor sites, and suppress tumor growth without adverse side effects.

Conclusion

Our results suggested DOX@NP with potent potential as a promising nanocarrier for TNBC therapy, which deserved further investigation for other cancer treatment.

HSA-templated self-generation of gold nanoparticles for tumor vaccine delivery and combinational therapy

Drug delivery systems (DDS) play a vital role in the construction of tumor vaccines and can promote their therapeutic effect. Taking advantage of the versatile binding sites and bioreduction ability of human serum albumin (HSA), Au ions could be absorbed, reduced and nucleated to generate gold nanoparticles (AuNPs) on HSA without complicated intermediates, forming a DDS that can transform light to heat. Here, we designed self-generated AuNPs templated by HSA (HSA@AuNP). The HSA@AuNPs can deliver peptides, amplify the immune response and achieve combined photothermal therapy and immunotherapy. Human melanoma antigen gp100_25-33 (hgp100) peptide, a common hydrophilic tumor vaccine peptide that can be easily encapsulated in HSA, was chosen to be incorporated into the HSA@AuNPs. The in vitro and in vivo studies demonstrated that the nanoparticles can mediate light-to-heat transduction under near-infrared irradiation (NIR), achieving tumor ablation and enhancing antitumor immunity. Our design can insulate toxic agents, streamline flux, increase the transition efficiency of interactants and improve the product yield, contributing a novel modality for facile and green synthesis of nanovaccines.

Poly(2-ethyl-2-oxazoline)-IR780 conjugate nanoparticles for breast cancer phototherapy

Aims: To address the limitations of IR780 by preparing hydrophilic polymer-IR780 conjugates and to employ these conjugates in the assembly of nanoparticles (NPs) intended for cancer photothermal therapy. Materials & methods: The cyclohexenyl ring of IR780 was conjugated for the first time with thiol-terminated poly(2-ethyl-2-oxazoline) (PEtOx). This novel poly(2-ethyl-2-oxazoline)-IR780 (PEtOx-IR) conjugate was combined with D-α-tocopheryl succinate (TOS), leading to the assembly of mixed NPs (PEtOx-IR/TOS NPs). Results: PEtOx-IR/TOS NPs displayed optimal colloidal stability as well as cytocompatibility in healthy cells at doses within the therapeutic range. In turn, the combination of PEtOx-IR/TOS NPs and near-infrared light reduced heterotypic breast cancer spheroid viability to just 15%. Conclusion: PEtOx-IR/TOS NPs are promising agents for breast cancer photothermal therapy.

A highly efficient polydopamine encapsulated clinical ICG theranostic nanoplatform for enhanced photothermal therapy of cervical cancer

Photothermal therapy (PTT) is a safe and efficient anti-tumor treatment. A photothermal agent (PTA) with good biocompatibility and strong photothermal properties is of great importance for PTT. In this study, near-infrared (NIR) excitable clinical indocyanine green (ICG) was utilized as a PTA and further encapsulated by another PTA polydopamine (PDA) to form highly stable and efficient ICG@PDA nanoparticles (NPs). Then the ICG@PDA NPs were modified with methoxy polyethylene glycol amine (mPEG₂₀₀₀-NH₂) to form biocompatible ICG@PDA@PEG NPs. ICG@PDA@PEG NPs showed good water solubility and a spherical shape with an average size of 140 nm. Furthermore, the photothermal properties of ICG@PDA@PEG NPs were studied and excellent photothermal performance with a photothermal conversion efficiency of 43.7% under 808 nm laser irradiation was achieved. Then, the PTT properties of ICG@PDA@PEG NPs were confirmed on HeLa cells with an efficiency of 86.1%. Meanwhile, the in vivo biocompatibility and toxicity of ICG@PDA@PEG NPs were evaluated. No apparent in vivo toxicity was observed in 24 hours and 7 days. Next, in vivo PTT analysis was conducted for cervical tumor-bearing nude mice under 808 nm laser excitation. It showed a good anti-tumor effect in vivo. Thus, ICG@PDA@PEG NPs exhibited great potential for safe and efficient photothermal therapy in anti-tumor therapy.

"Targeting Design" of Nanoparticles in Tumor Therapy

Tumor-targeted therapy based on nanoparticles is a popular research direction in the biomedical field. After decades of research and development, both the passive targeting ability of the inherent properties of NPs and the active targeting based on ligand receptor interaction have gained deeper understanding. Unfortunately, most targeted delivery strategies are still in the preclinical trial stage, so it is necessary to further study the biological fate of particles in vivo and the interaction mechanism with tumors. This article reviews different targeted delivery strategies based on NPs, and focuses on the physical and chemical properties of NPs (size, morphology, surface and intrinsic properties), ligands (binding number/force, activity and species) and receptors (endocytosis, distribution and recycling) and other factors that affect particle targeting. The limitations and solutions of these factors are further discussed, and a variety of new targeting schemes are introduced, hoping to provide guidance for future targeting design and achieve the purpose of rapid transformation of targeted particles into clinical application.

Identification and Validation of an m6A Modification of JAK-STAT Signaling Pathway–Related Prognostic Prediction Model in Gastric Cancer

Background: Gastric cancer (GC) is one of the malignant tumors worldwide. Janus (JAK)–signal transduction and activator of transcription (STAT) signaling pathway is involved in cellular biological process and immune function. However, the association between them is still not systematically described. Therefore, in this study, we aimed to identify key genes involved in JAK-STAT signaling pathway and GC, as well as the potential mechanism.

Methods: The Cancer Genome Atlas (TCGA) database was the source of RNA-sequencing data of GC patients. Gene Expression Omnibus (GEO) database was used as the validation set. The predictive value of the JAK-STAT signaling pathway-related prognostic prediction model was examined using least absolute shrinkage and selection operator (LASSO); survival, univariate, and multivariate Cox regression analyses; and receiver operating characteristic curve (ROC) analyses to examine the predictive value of the model. Quantitative real-time polymerase chain reaction (qRT-PCR) and chi-square test were used to verify the expression of genes in the model and assess the association between the genes and clinicopathological parameters of GC patients, respectively. Then, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment analysis, version 3.0 (GSEA), sequence-based RNA adenosine methylation site predictor (SRAMP) online websites, and RNA immunoprecipitation (RIP) experiments were used to predict the model-related potential pathways, m6A modifications, and the association between model genes and m6A.

Results: A four-gene prognostic model (GHR, PIM1, IFNA8, and IFNB1) was constructed, namely, riskScore. The Kaplan–Meier curves suggested that patients with high riskScore expression had a poorer prognosis than those with low riskScore expression (p = 0.006). Multivariate Cox regression analyses showed that the model could be an independent predictor (p < 0.001; HR = 3.342, 95%, CI = 1.834–6.088). The 5-year area under time-dependent ROC curve (AUC) reached 0.655. The training test set verified these results. Further analyses unveiled an enrichment of cancer-related pathways, m6A modifications, and the direct interaction between m6A and the four genes.

Conclusion: This four-gene prognostic model could be applied to predict the prognosis of GC patients and might be a promising therapeutic target in GC.

Photothermally responsive theranostic nanocomposites for near-infrared light triggered drug release and enhanced synergism of photothermo-chemotherapy for gastric cancer

Near-infrared (NIR) photothermal therapy plays a critical role in the cancer treatment and diagnosis as a promising carcinoma treatment modalities nowadays. However, development of clinical application has been greatly limited due to the inefficient drug release and low tumor accumulation. Herein, we designed a NIR-light triggered indocyanine green (ICG)-based PCL core/P(MEO₂MA-b-HMAM) shell nanocomposites (PPH@ICG) and evaluated their therapeutic effects in vitro and in vivo. The anticancer drug 5-fluorouracil (5Fu) and the photothermal agent ICG were loaded into a thermo-sensitive micelle (PPH@5Fu@ICG) by self-assembly. The nanoparticles formed were characterized using transmission electron microscopy, dynamic light scattering, and fluorescence spectra. The thermo-sensitive copolymer (PPH@5Fu@ICG) showed a great temperature-controlled drug release response with lower critical solution temperature. In vitro cellular uptake and TEM imaging proved that PPH@5Fu@ICG nanoparticles can home into the lysosomal compartments under NIR. Moreover, in gastric tumor-bearing nude mice, PPH@5Fu@ICG + NIR group exhibited excellent improvement in antitumor efficacy based on the NIR-triggered thermo-chemotherapy synergy, both in vitro and in vivo. In summary, the proposed strategy of synergistic photo-hyperthermia chemotherapy effectively reduced the 5Fu dose, toxic or side effect, which could serve as a secure and efficient approach for cancer theranostics.

Poly-β-Cyclodextrin-coated neodymium-containing copper sulfide nanoparticles as an effective anticancer drug carrier

Aim: This study aims at tuning the properties of the nanoparticles by incorporating neodymium, exploring the sustained release of drug, and the anticancer activity on breast cancer cells.Methods: The crystal characteristics of NdCuS₂ nanoparticles are analyzed using X-ray diffraction. The morphology and size of the nanoparticles were characterized using Transmission Electron Microscope and particle size analyzer. The rate of release of the encapsulated camptothecin and anticancer effects on breast cancer cells are investigated.Results: The nanoparticles are rod-shaped, 132 ± 8 nm long and 27 ± 7 nm wide. The band gap of the nanoparticles is 4.85 eV. The drug encapsulation efficiency is 94.76% (w/w). The drug is released in a sustained manner, over a period of 180 hours. The cytotoxicity of the camptothecin-loaded NPs is examined on MDA-MB-231 cells and the IC50 is 4.39 µg mL^-1Conclusion: The NdCuS₂ nanoparticles are promising as theranostic agents considering their material characteristics and anticancer activity.

Chemical Modification of Chitosan for Developing Cancer Nanotheranostics

Cancer is a worldwide public health issue that has not been conquered. Theranostics, the combination of a therapeutic drug and imaging agent in one formulation using nanomaterials, has been developed to better cure cancer in recent years. Although diverse biomaterials have been applied in cancer theranostics, chitosan (CS), a natural polysaccharide bearing easy modification sites with excellent biocompatibility and biodegradability, shows great potential for developing cancer nanotheranostics. In this review, we seek to describe the chemical functionalities of CS used in cancer theranostics and their synthesis methods. We also present recent discoveries and research progresses on how the CS functionalization could improve the delivery efficiency of CS-based nanotheranostics. Finally, we report several case studies about the application of CS-based nanotheranostics. This paper focuses on the strategies to construct CS-based theranostics systems via chemical routes and highlights their applications in cancer treatment, which can provide useful references for further studies.

Hsa_circ_0000081 promotes the function of gastric cancer through sponging hsa-miR-423-5p to influence 3-phosphoinositide-dependent kinase 1 expression

Gastric cancer (GC) is one of the most common malignancies in the world, and effective therapeutic targets need to be identified for this type of cancer. In this study, circular RNA (circRNA) microarray analysis was utilized to screen differentially expressed circRNA in GC. Using quantitative reverse transcription polymerase chain reaction (qRT-PCR), hsa_circ_0000081 (circRNA-0000081) expression was found to be up-regulated in tissues and cells and was negative correlated with patients' survival time. RNase R and Actinomycin D assays indicated that circRNA-0000081 was significantly more resistant to R enzyme and had a longer half-life than linear RNA. Moreover, the knockdown or overexpression of circRNA-000081 could influence the proliferation, migration, and invasion potential of GC. Finally, dual luciferase reporter, RNA immunoprecipitation, qRT-PCR, and western blotting assays were used to verify the targeting relationship between circRNA-000081 and miRNA-423-5p or miRNA-423-5p and 3-phosphoinositide-dependent kinase 1 (PDPK1). In conclusion, circRNA-0000081 promotes the function of GC through sponging hsa-miR-423-5p to influence PDPK1 expression, which has a promising therapeutic potential for treating patients with GC.

Nanoparticles in Clinical Translation for Cancer Therapy

The advent of cancer therapeutics brought a paradigm shift from conventional therapy to precision medicine. The new therapeutic modalities accomplished through the properties of nanomaterials have extended their scope in cancer therapy beyond conventional drug delivery. Nanoparticles can be channeled in cancer therapy to encapsulate active pharmaceutical ingredients and deliver them to the tumor site in a more efficient manner. This review enumerates various types of nanoparticles that have entered clinical trials for cancer treatment. The obstacles in the journey of nanodrug from clinic to market are reviewed. Furthermore, the latest developments in using nanoparticles in cancer therapy are also highlighted.

Versatile and Robust Method for Antibody Conjugation to Nanoparticles with High Targeting Efficiency

The application of antibodies in nanomedicine is now standard practice in research since it represents an innovative approach to deliver chemotherapy agents selectively to tumors. The variety of targets or markers that are overexpressed in different types of cancers results in a high demand for antibody conjugated-nanoparticles, which are versatile and easily customizable. Considering up-scaling, the synthesis of antibody-conjugated nanoparticles should be simple and highly reproducible. Here, we developed a facile coating strategy to produce antibody-conjugated nanoparticles using 'click chemistry' and further evaluated their selectivity towards cancer cells expressing different markers. Our approach was consistently repeated for the conjugation of antibodies against CD44 and EGFR, which are prominent cancer cell markers. The functionalized particles presented excellent cell specificity towards CD44 and EGFR overexpressing cells, respectively. Our results indicated that the developed coating method is reproducible, versatile, and non-toxic, and can be used for particle functionalization with different antibodies. This grafting strategy can be applied to a wide range of nanoparticles and will contribute to the development of future targeted drug delivery systems.

Polymer-Based Nanosystems-A Versatile Delivery Approach

Polymer-based nanoparticles of tailored size, morphology, and surface properties have attracted increasing attention as carriers for drugs, biomolecules, and genes. By protecting the payload from degradation and maintaining sustained and controlled release of the drug, polymeric nanoparticles can reduce drug clearance, increase their cargo's stability and solubility, prolong its half-life, and ensure optimal concentration at the target site. The inherent immunomodulatory properties of specific polymer nanoparticles, coupled with their drug encapsulation ability, have raised particular interest in vaccine delivery. This paper aims to review current and emerging drug delivery applications of both branched and linear, natural, and synthetic polymer nanostructures, focusing on their role in vaccine development.

Indoleamine 2,3-dioxygenase (Ido) inhibitors and their nanomedicines for cancer immunotherapy

Indoleamine 2,3-dioxygenase (IDO) as a principle enzyme in tryptophan (Trp) catabolism, modulates immune responses and promotes cancer progression. In recent decades, the newly emerging IDO inhibitors are regarded as the breakthrough for cancer immunotherapy. Intensified efforts have been increasingly made to, on the one hand, optimize the IDO inhibitors-based combination therapy in clinical trials; on the other hand, develop IDO inhibitors nanomedicines for tumor-targeted delivery in preclinical studies. This review will discuss the types of IDO inhibitors and the relevant clinical trials, especially those of the feasible combined therapeutic modalities. Moreover, it would be the first time to overview the cutting-edge nanomedicines that combine IDO inhibitors with other therapeutic modalities (e.g., chemotherapy, radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT) and immune checkpoint blockade) to effectively improve the effect of cancer therapy. Lastly, the prospects of IDO inhibitors in terms of clinical application and potential breakthroughs will be briefly discussed.

Polymer encapsulated clinical ICG nanoparticles for enhanced photothermal therapy and NIR fluorescence imaging in cervical cancer

Photothermal therapy (PTT) is a popular tumor therapy method, which is based on efficient photothermal nanoagents (PTNs). Clinical Indocyanine Green (ICG), as a Food and Drug Administration (FDA) approved agent, is an often-used PTN, meanwhile it is also a good near-infrared (NIR) fluorescence contrast agent. However, the further applications of ICG in biomedical fields are limited due to its poor stability. In this study, ICG was encapsulated by the amphiphilic polymer poly(styrene-co-maleic anhydride) (PSMA) to form ICG@PSMA nanoparticles. Furthermore, optical and thermal characteristics of ICG@PSMA nanoparticles were studied in detail. Strong NIR fluorescence and excellent photothermal properties of ICG@PSMA nanoparticles under 808 nm laser irradiation were measured. Besides, favorable biocompatibility of ICG@PSMA nanoparticles was demonstrated on a human cervical cancer cell line (HeLa) via cell viability studies. Hence, ICG@PSMA nanoparticles were further applied to enhanced PTT of living HeLa cells under 808 nm excitation, and a high PTT efficiency of ∼70% was obtained. The novel ICG nanoparticles as a promising PTT nanoplatform could offer an opportunity for further tumour treatments.

PSMA encapsulated Clinical ICG to form ICG@PSMA nanoparticles. ICG@PSMA nanoparticles showed strong NIR fluorescence and excellent photothermal properties.