Mitochondria-Targeted Thymidylate Synthase Inhibitor Based on Fluorescent Molecularly Imprinted Polymers for Tumor Antimetabolic Therapy.

Antimetabolites targeting thymidylate synthase (TS), such as 5-fluorouracil and capecitabine, have been widely used in tumor therapy in the past decades. Here, we present a strategy to construct mitochondria-targeted antimetabolic therapeutic nanomedicines based on fluorescent molecularly imprinted polymers (FMIP), and the nanomedicine was denoted as Mito-FMIP. Mito-FMIP, synthesized using fluorescent dye-doped silica as the carrier and amino acid sequence containing the active center of TS as the template peptide, could specifically recognize and bind to the active site of TS, thus inhibiting the catalytic activity of TS, and therefore hindering subsequent DNA biosynthesis, ultimately inhibiting tumor growth. The imprinting factor of FMIP reached 2.9, and the modification of CTPB endowed Mito-FMIP with the ability to target mitochondria. In vitro experiments demonstrated that Mito-FMIP was able to efficiently aggregate in mitochondria and inhibit CT26 cell proliferation by 59.9%. The results of flow cytometric analysis showed that the relative mean fluorescence intensity of Mito-FMIP accumulated in the mitochondria was 3.4-fold that of FMIP. In vivo experiments showed that the tumor volume of the Mito-FMIP-treated group was only one third of that of the untreated group. In addition, Mito-FMIP exibited the maximum emission wavelength at 682 nm, which allowed it to be used for fluorescence imaging of tumors. Taken together, this study provides a new strategy for the construction of nanomedicines with antimetabolic functions based on molecularly imprinted polymers.

Biomaterials promote in vivo generation and immunotherapy of CAR-T cells.

Chimeric antigen receptor-T (CAR-T) cell therapy based on functional immune cell transfer is showing a booming situation. However, complex manufacturing processes, high costs, and disappointing results in the treatment of solid tumors have limited its use. Encouragingly, it has facilitated the development of new strategies that fuse immunology, cell biology, and biomaterials to overcome these obstacles. In recent years, CAR-T engineering assisted by properly designed biomaterials has improved therapeutic efficacy and reduced side effects, providing a sustainable strategy for improving cancer immunotherapy. At the same time, the low cost and diversity of biomaterials also offer the possibility of industrial production and commercialization. Here, we summarize the role of biomaterials as gene delivery vehicles in the generation of CAR-T cells and highlight the advantages of in-situ construction in vivo. Then, we focused on how biomaterials can be combined with CAR-T cells to better enable synergistic immunotherapy in the treatment of solid tumors. Finally, we describe biomaterials' potential challenges and prospects in CAR-T therapy. This review aims to provide a detailed overview of biomaterial-based CAR-T tumor immunotherapy to help investigators reference and customize biomaterials for CAR-T therapy to improve the efficacy of immunotherapy.

A Novel Hexokinases Inhibitor Based on Molecularly Imprinted Polymer for Combined Starvation and Enhanced Photothermal Therapy of Malignant Tumors.

The heat tolerance of tumor cells induced by heat shock proteins (HSPs) is the major factor that seriously hinders further application of PTT, as it can lead to tumor inflammation, invasion, and even recurrence. Therefore, new strategies to inhibit HSPs expression are essential to improve the antitumor efficacy of PTT. Here, we prepared a novel nanoparticle inhibitor by synthesizing molecularly imprinted polymers with a high imprinting factor (3.1) on the Prussian Blue surface (PB@MIP) for combined tumor starvation and photothermal therapy. Owing to using hexokinase (HK) epitopes as the template, the imprinted polymers could inhibit the catalytic activity of HK to interfere with glucose metabolism by specifically recognizing its active sites and then achieve starvation therapy by restricting ATP supply. Meanwhile, MIP-mediated starvation downregulated the ATP-dependent expression of HSPs and then sensitized tumors to hyperthermia, ultimately improving the therapeutic effect of PTT. As the inhibitory effect of PB@MIP on HK activity, more than 99% of the mice tumors were eliminated by starvation therapy and enhanced PTT.

Multimode Sensing Platform Based on Turn-On Fluorescent Silicon Nanoparticles for Monitoring of Intracellular pH and GSH.

Various physiological activities and metabolic reactions of cells need to be carried out under the corresponding pH environment. Intracellular GSH as an acid tripeptide and an important reducing substance also plays an important role in maintaining cellular acid-base balance and redox balance. Therefore, developing a method to monitor pH and GSH and their changes in cells is necessary. Herein, we developed a novel turn-on fluorescent silicon nanoparticles (SiNPs) using N-(2-aminoethyl)-3-aminopropyltrimethoxysilane as the silicon source and dithiothreitol as the reducing agent via a one-pot hydrothermal method. It was worth mentioning that the fluorescence intensity of the SiNPs increased along with the acidity increase, making the SiNPs have excellent pH and GSH sensing capability. Furthermore, the pH and GSH sensing performance of the SiNPs in the cell was verified by confocal imaging and flow cytometry experiment. Based on the above, the prepared SiNPs had the potential to be used as an intracellular pH and GSH multimode fluorescent sensing platform and exhibited the ability to distinguish between normal cells and cancer cells.

Phosphate-Degradable Nanoparticles Based on Metal-Organic Frameworks for Chemo-Starvation-Chemodynamic Synergistic Antitumor Therapy.

Chemodynamic therapy (CDT) was regarded as a promising approach for tumor treatment. However, owing to the insufficient amount of endogenous hydrogen peroxide (H2O2) in tumor cells, the efficacy of CDT was limited. In this study, we designed phosphate-responsive nanoparticles (denoted as MGDFT NPs) based on metal-organic frameworks, which were simultaneously loaded with drug doxorubicin (DOX) and glucose oxidases (GOx). The decorated GOx could act as a catalytic nanomedicine for the response to the abundant glucose in the tumor microenvironment, generating a great deal of H2O2, which would enhance the Fenton reaction and produce toxic hydroxyl radicals (·OH). Meanwhile, the growth of tumors would also be inhibited by overconsuming the intratumoral glucose, which was the "fuel" for cell proliferation. When the nanoparticles entered into tumor cells, a high concentration of phosphate induced structure collapse, releasing the loaded DOX for chemotherapy. Furthermore, the decoration of target agents endowed the nanoparticles with favorable target ability to specific tumor cells and mitochondria. Consequently, the designed MGDFT NPs displayed desirable synergistic therapeutic effects via combining chemotherapy, starvation therapy, and enhanced Fenton reaction, facilitating the development of multimodal precise antitumor therapy.

Targeted Mitochondrial Fluorescence Imaging-Guided Tumor Antimetabolic Therapy with the Imprinted Polymer Nanomedicine Capable of Specifically Recognizing Dihydrofolate Reductase.

As we all know, inhibiting the activity of dihydrofolate reductase (DHFR) has always been an effective strategy for folate antimetabolites to treat tumors. In the past, it mainly relied on chemical drugs. Here, we propose a new strategy, (3-propanecarboxyl)triphenylphosphonium bromide (CTPB)-modified molecularly imprinted polymer nanomedicine (MIP-CTPB). MIP-CTPB prepared by imprinting the active center of DHFR can specifically bind to the active center to block the catalytic activity of DHFR, thereby inhibiting the synthesis of DNA and ultimately inhibiting the tumor growth. The modification of CTPB allows the nanomedicine to be targeted and enriched in mitochondria, where DHFR is abundant. The confocal laser imaging results show that MIP-CTPB can target mitochondria. Cytotoxicity experiments show that MIP-CTPB inhibits HeLa cell proliferation by 42.2%. In vivo experiments show that the tumor volume of the MIP-CTPB-treated group is only one-sixth of that of the untreated group. The fluorescent and paramagnetic properties of the nanomedicine enable targeted fluorescence imaging of mitochondria and T2-weighted magnetic resonance imaging of tumors. This research not only opens up a new direction for the application of molecular imprinting, but also provides a new idea for tumor antimetabolic therapy guided by targeted mitochondrial imaging.

Tumor-Sensitive Biodegradable Nanoparticles of Molecularly Imprinted Polymer-Stabilized Fluorescent Zeolitic Imidazolate Framework-8 for Targeted Imaging and Drug Delivery.

Targeting enrichment of nanocarriers at tumor sites and effective drug release are critical in cancer treatment. Accordingly, we used fluorescent zeolitic imidazolate framework-8 nanoparticles loaded with doxorubicin (FZIF-8/DOX) as the core and a molecularly imprinted polymer (MIP) as the shell to synthesize tumor-sensitive biodegradable FZIF-8/DOX-MIP nanoparticles (FZIF-8/DOX-MIPs). The MIP prepared with the epitope of CD59 cell membrane glycoprotein as the template allowed FZIF-8/DOX-MIPs to be enriched to tumor sites by actively targeting recognition of MCF-7 cancer cells (CD59-positive). Moreover, using N,N'-diacrylylcystamine as the cross-linker and dimethylaminoethyl methacrylate as the main monomer, the MIP's framework will be broken under the stimulation of a tumor microenvironment (high-concentration glutathione and weakly acidic), so that the internal FZIF-8/DOX is exposed to a microacidic environment to release DOX through further degradation. More importantly, the ability of FZIF-8/DOX-MIPs in targeted fluorescence imaging and effective drug release has been validated both in vitro and in vivo. Compared to other cells and nanoparticles, FZIF-8/DOX-MIPs were more capable of being phagocytosed by MCF-7 cells and were more lethal to MCF-7 cells. In the comparative experiments carried out on tumor-bearing mice, FZIF-8/DOX-MIPs had the best inhibitory effect on the growth of MCF-7 tumors. Furthermore, the FZIF-8/DOX-MIPs can serve as a diagnostic agent because of the active targeting of MCF-7 cells and the stronger red fluorescence of the embedded carbon quantum dots. Because of the active targeting ability, good biocompatibility, tumor-sensitive biodegradability, and effective drug release performance, FZIF-8/DOX-MIPs can be widely used in tumor imaging and treatment.

Epitope Molecularly Imprinted Polymer Nanoparticles for Chemo-/Photodynamic Synergistic Cancer Therapy Guided by Targeted Fluorescence Imaging.

It is a still tough task to precisely target cancer cells and efficiently improve the therapeutic efficacy of various therapies at the same time. Here, dual-template imprinting polymer nanoparticles (MIPs) with a core-shell structure were prepared, in which fluorescent silica nanoparticles (FSiO2) were the core and the imprinted polymer layers were the outermost shell. The imprinted layer was designed and constructed via free-radical precipitation approach on the surface of FSiO2, which simultaneously encapsulated gadolinium-doped silicon quantum dots and photosensitizers (Ce6). During the polymerization process, two template molecules were introduced into the mixtures, one was the epitope of CD59 protein (YNCPNPTADCK), which was overexpressed on the surface of a great deal of the solid cancers, and the other was antitumor agent doxorubicin (DOX) to be used for chemotherapy. Furthermore, the embedded Ce6 could generate toxic 1O2 under 655 nm laser irradiation to kill cancer cells, combining with the loaded-DOX to obtain a synergistic cancer therapy. Moreover, owing to the introduction of gadolinium-doped silicon quantum dots, Ce6, and DOX, the MIPs were endowed with targeted fluorescence imaging (FI) and MR imaging (MRI). In vitro and in vivo experiments had been conducted to demonstrate the excellent targeting ability and desirable treatment effect with negligible toxicity to healthy tissues and organs. As a consequence, the designed MIPs can promote the development of targeted recognition against biomarkers and precise treatment guided with cell imaging tools.

Combined Effects of Plant Sterols with Low Ratio of n-6/n-3 Polyunsaturated Fatty Acids against Atherosclerosis in ApoE-/- Mice.

The effects of low ratio of n-6/n-3 polyunsaturated fatty acids (PUFA) have been clarified against atherosclerosis. Increasing evidence indicated that plant sterols (PS) have a significant cholesterol-lowering effect. This study explored the effects of PS combined with n-6/n-3 (2:1) PUFA on atherosclerosis and investigated the possible mechanism. In ApoE-/- mice, the milk fat in high fat diets was replaced with n-6/n-3 (2:1) PUFA alone or supplemented with 6% PS for 16 weeks. Results demonstrated that PS combined with PUFA exerted commentary and synergistic effects on ameliorating atherosclerosis, improving lipid metabolism and lipid deposition in liver, and alleviating inflammatory response. These changes were accompanied with decreased serum TC, TG, LDL-C and increased fecal cholesterol efflux, as well as the lower inflammatory cytokine CRP, IL-6, TNF-α. It is suggested that the underlying mechanism of PS combined with n-6/n-3 (2:1) PUFA promoting the fecal cholesterol efflux may be mediated by liver X receptor α/ATP-binding cassette transporter A1 pathway.

Highly Effective Drug Delivery and Cell Imaging Using Fluorescent Double-Imprinted Nanoparticles by Targeting Recognition of the Epitope of Membrane Protein.

Nanocarriers with both targeting ability and stable loading of drugs can more effectively deliver drugs to precise tumor sites for therapeutic effects. Accordingly, we have rationally designed fluorescent molecularly imprinted polymer nanoparticles (FMIPs), which use N-terminal epitope of P32 membrane protein as the primary template and doxorubicin (DOX) as the secondary template. The DOX imprinted cavity can stably carry the drug and the epitope-imprinted cavity allows FMIPs to actively recognize the P32-positive 4T1 cancer cells. The targeted therapeutic effect of DOX-loaded FMIPs (FMIPs@DOX) is investigated in vitro and in vivo. The FMIPs@DOX only causes apoptosis in 4T1 cancer cells compared to C8161 cells (expressing low level of P32). In addition, highly effective inhibition of 4T1 malignant breast tumors using FMIPs@DOX is achieved in the model of tumor-bearing mice. Importantly, the antitumor effect achieved by intravenous injection of FMIPs@DOX is almost identical to that by intratumoral injection. Furthermore, the FMIPs can serve as a targeted fluorescence imaging agent due to the high specificity of the epitope-imprinted cavity and the stable fluorescence of the embedded silicon nanoparticles. These results demonstrate the effectiveness of the FMIPs for active targeted drug delivery and imaging. Furthermore, the FMIPs provide a direction for drug-loaded nanocarrier.

pH-Responsive Polymer-Stabilized ZIF-8 Nanocomposites for Fluorescence and Magnetic Resonance Dual-Modal Imaging-Guided Chemo-/Photodynamic Combinational Cancer Therapy.

A multifunctional diagnosis and treatment integration platform is crucial in cancer treatments. Here, we show that by integrating Gd-doped silicon nanoparticles (Si-Gd NPs), chlorine e6 (Ce6), doxorubicin (DOX), zeolitic imidazolate framework-8 (ZIF-8), poly(2-(diethylamino)ethyl methacrylate) polymers (HOOC-PDMAEMA-SH), and folic acid-poly(ethylene glycol)-maleimide (MaL-PEG-FA) into one single nanoplatform by a self-assembly method, novel multifunctional MOFs (named FZIF-8/DOX-PD-FA) are synthesized with great biocompatibility and tumor targeting as well as pH responsiveness and no drug leakage for drug delivery. In the design, Si-Gd NPs and Ce6 embedded in the nanocomposites are used for magnetic resonance and fluorescence dual-modal imaging, respectively. DOX loaded by the FZIF-8/DOX-PD-FA porous structure is used for chemotherapy, while Ce6 is excited by near-infrared radiation (NIR) for photodynamic therapy. In addition, the pH-responsive ability of HOOC-PDMAEMA-SH to effectively prevent drug leakage is demonstrated by drug release studies in vitro. From the results of confocal microscopy imaging in vitro and fluorescence/magnetic resonance imaging in vivo, FZIF-8/DOX-PD-FA showed a targeting effect on MCF-7 cancer cells. More importantly, the results of treatment experiments on tumor-bearing mice showed that the tumor volume of the FZIF-8/DOX-PD-FA + NIR group is decreased the most compared to the original volume. Owing to the unique dual-modal imaging capability and excellent chemo-/photodynamic combinational cancer therapy effect, the present hybrid nanocarrier provides a new research platform for a new generation of theranostic nanoparticles.