Copolymer-Green-Synthesized Copper Oxide Nanoparticles Enhance Folate-Targeting in Cervical Cancer Cells In Vitro

Cervical cancer is fast becoming a global health crisis, accounting for most female deaths in low- and middle-income countries. It is the fourth most frequent cancer affecting women, and due to its complexity, conventional treatment options are limited. Nanomedicine has found a niche in gene therapy, with inorganic nanoparticles becoming attractive tools for gene delivery strategies. Of the many metallic nanoparticles (NPs) available, copper oxide NPs (CuONPs) have been the least investigated in gene delivery. In this study, CuONPs were biologically synthesized using Melia azedarach leaf extract, functionalized with chitosan and polyethylene glycol (PEG), and conjugated to the targeting ligand folate. A peak at 568 nm from UV-visible spectroscopy and the characteristic bands for the functional groups using Fourier-transform infrared (FTIR) spectroscopy confirmed the successful synthesis and modification of the CuONPs. Spherical NPs within the nanometer range were evident from transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The NPs portrayed exceptional binding and protection of the reporter gene, pCMV-Luc-DNA. In vitro cytotoxicity studies revealed cell viability >70% in human embryonic kidney (HEK293), breast adenocarcinoma (MCF-7), and cervical cancer (HeLa) cells, with significant transgene expression, obtained using the luciferase reporter gene assay. Overall, these NPs showed favorable properties and efficient gene delivery, suggesting their potential role in gene therapy.

Full Remission of CAR-Deficient Tumors by DOTAP-Folate Liposome Encapsulation of Adenovirus

Adenovirus (Ad)-based vectors have shown considerable promise for gene therapy. However, Ad requires the coxsackievirus and adenovirus receptor (CAR) to enter cells efficiently and low CAR expression is found in many human cancers, which hinder adenoviral gene therapies. Here, cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-folate liposomes (Df) encapsulating replication-deficient Ad were synthesized, which showed improved transfection efficiency in various CAR-deficient cell lines, including epithelial and hematopoietic cell types. When encapsulating replication-competent oncolytic Ad (TAV255) in DOTAP-folate liposome (TAV255-Df), the adenoviral structural protein, hexon, was readily produced in CAR-deficient cells, and the tumor cell killing ability was 5× higher than that of the non-encapsulated Ad. In CAR-deficient CT26 colon carcinoma murine models, replication-competent TAV255-Df treatment of subcutaneous tumors by intratumoral injection resulted in 67% full tumor remission, prolonged survival, and anti-cancer immunity when mice were rechallenged with cancer cells with no further treatment. The preclinical data shows that DOTAP-folate liposomes could significantly enhance the transfection efficiency of Ad in CAR-deficient cells and, therefore, could be a feasible strategy for applications in cancer treatment.

Stromal Barrier-Dismantled Nanodrill-Like and Cancer Cell-Targeted pH-Responsive Polymeric Micelles for Further Enhancing the Anticancer Efficacy of Doxorubicin

Cancer-associated fibroblasts (CAFs) were believed to establish a tight physical barrier and a dense scaffold for tumor cells to make them maintain immunosuppression and drug resistance, strongly hindering nanoparticles to penetrate into the core of tumor tissues and limiting the performance of tumor cell-targeted nanoparticles. Here, we fabricated the substrate Z-Gly-Pro of fibroblast activation protein α (FAPα) and folic acid-codecorated pH-responsive polymeric micelles (dual ligand-modified PEOz-PLA polymeric micelles, DL-PP-PMs) that possessed nanodrill and tumor cell-targeted functions based on Z-Gly-pro-conjugated poly(2-ethyl-2-oxazoline)-poly(D,l-lactide) (ZGP-PEOz-PLA), folic acid (FA)-conjugated PEOz-PLA (FA-PEOz-PLA), and PEOz-PLA for cancer therapy. The micelles with about 40 nm particle size and a narrow distribution exhibited favorable pH-activated endo/lysosome escape induced by their pH responsibility. In addition, the enhancement of in vitro cellular uptake and cytotoxicity to folate receptors or FAPα-positive cells for doxorubicin (DOX)/DL-PP-PMs compared with DOX/PP-PMs evidenced the dual target ability of DOX/DL-PP-PMs, which was further supported by in vivo biodistribution results. As expected, in the human oral epidermal carcinoma (KB) cells xenograft nude mice model, the remarkable enhancement of antitumor efficacy for DOX/DL-PP-PMs with low toxicity was observed compared with DOX/FA-PP-PMs and DOX/ZGP-PP-PMs. The possible mechanism was elucidated to be the dismantling of the stromal barrier by nanodrill-like DOX/DL-PP-PMs via the deletion of CAFs evidenced by the downregulation of α-SMA and inhibition of their functions proved by the decrease in the microvascular density labeled with CD31 and the reduction in the extracellular matrix detected by the collagen content, thereby promoting tumor penetration and enhancing their uptake by tumor cells. The present research offered an alternative approach integrating anticancer and antifibrosis effects in one delivery system to enhance the delivery efficiency and therapeutic efficacy of anticancer drugs.

Folate-targeting annonaceous acetogenins nanosuspensions: significantly enhanced antitumor efficacy in HeLa tumor-bearing mice

Annonaceous acetogenins (ACGs) are one of the most active constituents isolated from Annona species with potent antitumor activity. However, the poor solubility and severe side effect greatly limit their use in clinic. In this study, folic acid (FA) modified annonaceous acetogenins nanosuspensions (FA-PEG-ACGs-NSps) had been successfully prepared using DSPE-PEG-FA and soybean lecithin (SPC) as stabilizers. The resultant FA-PEG-ACGs-NSps had a mean particle size of 119.7 nm, a zeta potential of -23.0 mV and a high drug payload of 49.68%. The obtained ACGs-NSps had a good stability in various physiological media, and showed sustained drug release. Compared to common ACGs nanoparticles (PEG-ACGs-NSps), FA-PEG-ACGs-NSps showed significantly enhanced in vitro cytotoxicity against folate receptor-positive HeLa cell lines (IC50, 0.483 μg/mL vs. 0.915 μg/mL, p < .05), which could be effectively reversed simply by pretreatment of free FA. In vivo experiments demonstrated that FA-PEG-ACGs-NSps brought more drug molecules into tumors and greatly improved the antitumor efficacy (TIR, 76.45% vs. 25.29%, p < .001). Therefore, DSPE-PEG-FA is considered as a proper stabilizer with active targeting effect for ACGs-NSps to reduce toxicity, enlarge the safe dosage range and apply in clinic for the treatment of folate-positive tumors. Therefore, FA-PEG-ACGs-NSps may be a prospective drug delivery system for ACGs to improve their therapeutic window and find application in clinic to treat FR over-expressed tumors.

Development of fisetin-loaded folate functionalized pluronic micelles for breast cancer targeting

The natural flavonoid fisetin (FS) has shown anticancer properties but its in-vivo administration remains challenging due to its poor aqueous solubility. The aim of the study was to develop FS loaded pluronic127 (PF)-folic acid (FA) conjugated micelles (FS-PF-FA) by the way of increasing solubility, bioavailability and active targetability of FS shall increase its therapeutic efficacy. FA-conjugated PF was prepared by carbodiimide crosslinker chemistry. FS-PF-FA micelles were prepared by thin-film hydration method and evaluated in comparison with free FS and FS loaded PF micelles (FS-PF). The smooth surfaces with spherical in shape of FS-PF-PF micelles displayed smaller in size (103.2 ± 6.1 nm), good encapsulation efficiency (82.50 ± 1.78%), zeta potential (-26.7 ± 0.44 mV) and sustained FS release. Bioavailability of FS from FS-PF-PF micelles was increased by 6-fold with long circulation time, slower plasma elimination and no sign of tissue toxicity as compared to free FS. Further, the FS-PF-FA micelles demonstrated active targeting effect on folate overexpressed human breast cancer MCF-7 cells. The concentration of the drug needed for growth inhibition of 50% of cells in a designed time period (GI50) was 14.3 ± 1.2 µg/ml for FS while it was greatly decreased to 9.8 ± 0.78 µg/ml, i.e. a 31.46% decrease for the FS-PF. Furthermore, the GI50 value for FS-PF-FA was 4.9 ± 0.4 µg/ml, i.e. a 65.737% decrease compared to FS and 50% decrease compare to FS-PF. The results indicate that the FS-PF-FA micelles have the potential to be applied for targeting anticancer drug delivery.

Size of single-wall carbon nanotube affects the folate receptor-mediated cancer cell targeting

Advances in nanobiotechnology and targeting strategy could improve the delivery of therapeutic molecules into cancer cells, leading to improved treatment efficiency with minimal side effects on normal cells. To design an efficient nanocarrier, consideration of parameters that facilitate direct drug delivery into the target cells is important. We studied the effect of single-wall carbon nanotubes (SWNTs) size on their cell internalization level via the folate receptor-mediated pathway through folic acid targeting. Folate-SWNTs were covalently synthesized and characterized. Folate-SWNTs ≤ 450 nm had lower cell internalization level than folate-SWNTs >450 nm with a P value of ≤0.01. This indicated that using folate-SWNT with an average length of ≤450 nm was not suitable for receptor-mediated cancer cell targeting. Receptor-mediated uptake of folate-SWNTs is dependent on the nanoparticle length. However, sub-450 nm SWNTs could serve as a vehicle to transfer nucleic acids into the cells due to direct cell penetrance based on their needle-like structure. We find that SWNTs larger than 450 nm were suitable to target the cells through receptors. These results might provide a promising approach for designing more effective targeted delivery systems based on SWNTs.

Folate-conjugated liposomes target and deliver therapeutics to immune cells in a rat model of rheumatoid arthritis

AIM

We endeavored to create a folate-targeted liposome (Fol-liposome) that could selectively target areas of inflammation.

MATERIALS & METHODS

Fol-liposomes were prepared with encapsulated DiD fluorophore or betamethasone (BM) to image and treat an adjuvant-induced rat model of rheumatoid arthritis.

RESULTS

Fol-liposomes selectively accumulated in arthritic rat paws to a greater extent than nontargeted liposomes. When these Fol-liposomes were used to encapsulate BM and administered to arthritic rats, animals exhibited less paw swelling, lower arthritis scores, a reduction in bone erosion, less splenomegaly and better maintenance of body weight when compared with nontreated or nontargeted BM-containing liposome groups.

CONCLUSION

Fol-liposomes can selectively deliver imaging and therapeutic agents to sites of inflammation in a rat model of rheumatoid arthritis.

Block Copolymer Based Nanoparticles for Theranostic Intervention of Cervical Cancer: Synthesis, Pharmacokinetics, and in Vitro/in Vivo Evaluation in HeLa Xenograft Models

Polymer-based nanoparticles have proven to be viable carriers of therapeutic agents. In this study, we have developed nanoparticles (NPs) from polypeptide-polyethylene glycol based triblock and diblock copolymers. The synthesized block copolymers poly(ethylene glycol)-b-poly(glutamic acid)-b-poly(ethylene glycol) (GEG) and poly(ethylene glycol)-b-poly(glutamic acid) (EG) conjugated with folic acid for targeting specificity (EGFA) have been used to encapsulate methotrexate (MTX) to form M-GEG and M-EGFA NPs aimed at passive and active targeting of cervical carcinoma. In-vitro SRB cytotoxicity and hemolysis assays revealed that these NPs were cytocompatible to healthy human cells and hemocompatible to human RBCs. Cellular uptake by FACS demonstrated their prompt internalization by human cervical carcinoma (HeLa) cells and points toward an apoptotic mechanism of cell kill as confirmed by AO/EB staining as well as histological analysis of explanted HeLa tumors. Pharmacokinetics and biodistribution studies were performed in New Zealand albino rabbits and HeLa xenografted Athymic mice models, respectively, by radiolabeling these NPs with ^99mTc. Passive tumor accumulation and active targeting of MTX-loaded polymeric nanoparticles to folate expressing cells were confirmed by intravenous administration of these ^99mTc-labeled M-GEG and M-EGFA NPs in HeLa tumor bearing nude mice and clearly visualized by whole-body gamma-SPECT images of these mice. Survival studies of these xenografted mice established the antiproliferative effect of these MTX-loaded NPs while corroborating the targeting effect of folic acid. These studies proved that the M-GEG NPs and M-EGFA NPs could be effective alternatives to conventional chemotherapy along with simultaneous diagnostic abilities and thus potentially viable theranostic options for human cervical carcinoma.

Highlighting Cancer Cells with Halochromic Switches

Halochromic coumarin-oxazine prefluorophores and targeting folate ligands can be connected covalently to the side chains of amphiphilic polymers. The resulting macromolecular constructs assemble into nanoparticles in aqueous environments. The prefluorophores do not produce any detectable fluorescence at neutral pH, but are converted into fluorophores with intense visible emission at acidic pH. Protonation opens the oxazine heterocycle to shift bathochromically the coumarin absorption and activate fluorescence with a brightness per nanoparticle approaching 5 × 10⁵ M^-1 cm^-1. This value translates into a 170-fold enhancement relative to the isolated fluorophores dissolved in organic solvent. The folate ligands direct these multicomponent constructs into acidic intracellular compartments of folate-positive cells, where the prefluorophores switch to the corresponding fluorophores and produce fluorescence. The pH-induced activation of the signaling units ensures negligible background fluorescence from the extracellular matrix, which instead limits considerably the contrast accessible with model systems incorporating conventional nonactivatable fluorophores. Furthermore, no intracellular fluorescence can be detected when the very same measurements are performed with folate-negative cells. Nonetheless, control experiments demonstrate that the covalent connection of the prefluorophores to the polymer backbone of the amphiphilic constructs is essential to ensure selectivity. Model systems with prefluorophores noncovalently encapsulated cannot discriminate folate-positive from -negative cells. Thus, our structural design for the covalent integration of activatable signaling units and targeting ligands within the same nanostructured assembly together with the photophysical properties engineered into the emissive components offer the opportunity to highlight cancer cells selectively with high brightness and optimal contrast.

Efficient and Tumor Targeted siRNA Delivery by Polyethylenimine-graft-polycaprolactone-block-poly(ethylene glycol)-folate (PEI-PCL-PEG-Fol)

Efficient delivery of functional nucleic acids into specific cells or tissues is still a challenge for gene therapy and largely depends on targeted delivery strategies. The folate receptor (FR) is known to be overexpressed extracellularly on a variety of human cancers and is therefore an outstanding gate for tumor-targeted Trojan horse-like delivery of therapeutics. In this study, an amphiphilic and biodegradable ternary copolymer conjugated with folate as ligand, polyethylenimine-graft-polycaprolactone-block-poly(ethylene glycol)-folate (PEI-PCL-PEG-Fol) was synthesized and evaluated for targeted siRNA delivery via folate-FR recognition. The amphiphilic character of similar polymers was shown previously to support endosomal release of endocytosed nanocarriers and to promote formation of long circulating micelles. The obtained PEI-PCL-PEG-Fol exhibited less cytotoxicity in comparison with the corresponding ternary copolymer without folate (PEI-PCL-PEG) and with unmodified PEI25kDa. Stable micelle-like polyplexes with hydrodynamic diameters about 100 nm were found to have a zeta potential of +8.6 mV, which was lower than that of micelleplexes without folate-conjugation (+13-16 mV). Nonetheless, increased cellular uptake and in vitro gene knockdown of PEI-PCL-PEG-Fol/siRNA micelleplexes were observed in SKOV-3 cells, an FR overexpressing cell line, in comparison with the nonfolate-conjugated ones. Moreover, PEI-PCL-PEG-Fol/siRNA micelleplexes exhibited excellent stability in vivo during the analysis of 120 min and a longer circulation half life than hyPEI25kDa/siRNA polyplexes. Most interestingly, the targeted delivery system yielded 17% deposition of the i.v. injected siRNA per gram in the tumor after 24 h due to the effective folate targeting and the prolonged circulation.

Theranostic CuS Nanoparticles Targeting Folate Receptors for PET Image-Guided Photothermal Therapy

Copper sulfide nanoparticles (CuS NPs) have been reported as a single-compartment theranostic nanosystem to visualize and treat tumors simultaneously. However, few studies have investigated the in vivo tumor-targeted delivery of this class of nanoparticles. In this study, we introduced a tumor-specific targeting ligand, folic acid (FA), onto the surface of CuS NPs as a model system to demonstrate the feasibility of actively targeted CuS NPs for positron emission tomography (PET) imaging and PET image-guided photothermal therapy (PTT). A one-pot synthetic method was used for introducing FA to CuS NPs to yield FA-CuS NPs. Biodistribution studies in mice bearing folate receptor-expressing KB tumor showed significantly higher tumor uptake of FA-CuS NPs than non-targeted polyethylene glycol (PEG)-coated PEG-CuS NPs after intravenous injection. Moreover, tumor uptake of FA-CuS NPs could be effectively blocked by free FA. Biodistribution and clearance of ⁶⁴Cu-labeled FA-CuS NPs (FA-[⁶⁴Cu]CuS NPs) could be readily visualized by microPET (μPET), which confirmed a significantly higher level of tumor uptake of FA-[⁶⁴Cu]CuS NPs than non-targeted PEG-[⁶⁴Cu]CuS NPs. μPET image-guided PTT with FA-CuS NPs mediated substantially greater tumor damage compared with PTT mediated by PEG-CuS NPs. Thus, FA-CuS NPs is a promising candidate for PTT of folate receptor-positive tumors.

Synergistic effect of pH-responsive folate-functionalized poloxamer 407-TPGS-mixed micelles on targeted delivery of anticancer drugs

BACKGROUND

Doxorubicin (DOX), an anthracycline anticancer antibiotic, is used for treating various types of cancers. However, its use is associated with toxicity to normal cells and development of resistance due to overexpression of drug efflux pumps. Poloxamer 407 (P407) and vitamin E TPGS (D-α-tocopheryl polyethylene glycol succinate, TPGS) are widely used polymers as drug delivery carriers and excipients for enhancing the drug retention times and stability. TPGS reduces multidrug resistance, induces apoptosis, and shows selective anticancer activity against tumor cells. Keeping in view the problems, we designed a mixed micelle system encapsulating DOX comprising TPGS for its selective anticancer activity and P407 conjugated with folic acid (FA) for folate-mediated receptor targeting to cancer cells.

METHODS

FA-functionalized P407 was prepared by carbodiimide crosslinker chemistry. P407-TPGS/FA-P407-TPGS-mixed micelles were prepared by thin-film hydration method. Cytotoxicity of blank micelles, DOX, and DOX-loaded micelles was determined by alamarBlue(®) assay.

RESULTS

The size of micelles was less than 200 nm with encapsulation efficiency of 85% and 73% for P407-TPGS and FA-P407-TPGS micelles, respectively. Intracellular trafficking study using nile red-loaded micelles indicated improved drug uptake and perinuclear drug localization. The micelles show minimal toxicity to normal human cell line WRL-68, enhanced cellular uptake of DOX, reduced drug efflux, increased DOX-DNA binding in SKOV3 and DOX-resistant SKOV3 human ovarian carcinoma cell lines, and enhanced in vitro cytotoxicity as compared to free DOX.

CONCLUSION

FA-P407-TPGS-DOX micelles show potential as a targeted nano-drug delivery system for DOX due to their multiple synergistic factors of selective anticancer activity, inhibition of multidrug resistance, and folate-mediated selective uptake.

Folate receptor-β constitutes a marker for human proinflammatory monocytes

Activated macrophages are commonly involved in the pathogenesis of inflammatory and autoimmune diseases and have been frequently reported to overexpress FR-β. Although FR-targeted therapies aimed at eliminating activated macrophages have shown promise for treating inflammatory diseases, little work has been performed to evaluate whether other hematopoietic cells might also express FR-β. Analysis of peripheral blood cells with a mAb to human FR-β reveals that only monocytes express FR-β. Molecular characterization of these circulating monocytes further demonstrates that solely the classic/proinflammatory subset (CD14(high)CD16(-)) expresses the FR and that only CD14(high)CD16(-) FR-β(+) monocytes also display the ability to bind folate-linked molecules. Confirmation that this subset of monocytes indeed constitutes the proinflammatory subpopulation was obtained by demonstrating coexpression of FR-β with other proinflammatory markers, including CCR2 and HLA-DR. Synovial monocytes from the joints of patients with RA were also shown to express FR-β. As inhibition of the chemotaxis of proinflammatory monocytes into sites of inflammation has been explored frequently as a means of controlling autoimmune diseases, demonstration that FR-β is uniquely expressed on this proinflammatory subpopulation offers a new strategy to suppress migration of inflammatory monocytes into sites of inflammation.