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.

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.

Bimetallic molecularly imprinted nanozyme: Dual-mode detection platform.

Molecularly imprinted polymer nanozyme (MIL-101(Co,Fe)@MIP) with bimetallic active sites and high-efficiency peroxidase-like (POD-like) activity were synthesized for the ratiometric fluorescence and colorimetric dual-mode detection of vanillin with high selectivity and sensitivity. Compared with the monometallic nanozyme, the POD-like activity of bimetallic nanozyme was greatly enhanced by changing the electronic structure and surface structure. Ratiometric fluorescence and colorimetric dual-mode detection of vanillin in aqueous solution was realized by vanillin entering specific imprinted cavities and blocking the molecular channels on the surface of MIL-101(Co,Fe)@MIP and the dual-mode visual detection was also realized. The limits of detection were as low as 104 nM and 198 nM, respectively. The method proposed in this paper was applied to the real samples of ice cream and candy. And the recoveries were between 93.3% and 105.5%, which also reached a satisfactory degree. The further detection of dexamethasone and prednisone, two drugs belonging to glucocorticoid, proved that the nanozyme analysis method based on MIL-101(Co,Fe)@MIP could be developed into a sensing platform.

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.

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.

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.