Impedimetric Detection of Cancer Markers Based on Nanofiber Copolymers

The sensitive determination of folate receptors (FRs) in the early stages of cancer is of great significance for controlling the progression of cancerous cells. Many folic acid (FA)-based electrochemical biosensors have been utilized to detect FRs with promising performances, but most were complicated, non-reproducible, non-biocompatible, and time and cost consuming. Here, we developed an environmentally friendly and sensitive biosensor for FR detection. We proposed an electrochemical impedimetric biosensor formed by nanofibers (NFs) of bio-copolymers prepared by electrospinning. The biosensor combines the advantages of bio-friendly polymers, such as sodium alginate (SA) and polyethylene oxide (PEO) as an antifouling polymer, with FA as a biorecognition element. The NF nanocomposites were characterized using various techniques, including SEM, FTIR, zeta potential (ZP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). We evaluated the performance of the NF biosensor using EIS and demonstrated FR detection in plasma with a limit of detection of 3 pM. Furthermore, the biosensor showed high selectivity, reliability, and good stability when stored for two months. This biosensor was constructed from 'green credentials' holding polymers that are highly needed in the new paradigm shift in the medical industry.

Evaluation of Folate-Functionalized Nanoparticle Drug Delivery Systems-Effectiveness and Concerns

Targeting folate receptors is a potential solution to low tumor selectivity concerning conventional chemotherapeutics. Apart from antibody-drug conjugates, folate-functionalized nanoparticle drug delivery systems are interesting to be explored due to many advantages, yet currently, none seems to enter the clinical trials. Multiple in vitro evidence is available to support its efficacy compared to the non-targeting carrier and free drug formulation. Additionally, several studies pointed out factors affecting its effectiveness, including surface properties and endosomal trapping. However, in vivo biodistribution studies revealed issues that may arise from folate receptor targeting, including rapid liver uptake, subsequently reducing the nanoparticles' tumor uptake. This issue may be due to the folate receptor β expressed by the activated macrophages in the liver; route of administration and tumor location might also influence the targeting effectiveness. Moreover, it is perplexing to generalize nanoparticles reported from various publications, primarily due to the different formulations, lack of characterization, and experimental settings, making it harder to determine the accurate factor influencing targeting effectiveness.

Folic-Acid-Conjugated Thermoresponsive Polymeric Particles for Targeted Delivery of 5-Fluorouracil to CRC Cells

Colorectal cancer is the fourth most common cancer worldwide and the third most frequently diagnosed form of cancer associated with high mortality rates. Recently, targeted drug delivery systems have been under increasing attention owing to advantages such as high therapeutic effectiveness with a significant depletion in adverse events. In this report, we describe the biocompatible and thermoresponsive FA-conjugated PHEA-b-PNIPAAm copolymers as nanocarriers for the delivery of 5-FU. The block copolymers were obtained using RAFT (Reversible Addition-Fragmentation chain Transfer) polymerization and were characterized by methods such as SEC (Size Exclusion Chromatography), NMR (Nuclear Magnetic Resonance), UV-Vis (Ultraviolet-Visible), FT-IR (Fourier Transform Infrared) spectroscopy, and TGA (Thermogravimetric Analysis). Nanoparticles were formed from polymers with and without the drug-5-fluorouracil, which was confirmed using DLS (Dynamic Light Scattering), zeta potential measurements, and TEM (Transmission Electron Microscopy) imaging. The cloud points of the polymers were found to be close to the temperature of the human body. Eventually, polymeric carriers were tested as drug delivery systems for the safety, compatibility, and targeting of colorectal cancer cells (CRC). The biological evaluation indicated high compatibility with the representative host cells. Furthermore, it showed that proposed nanosystems might have therapeutic potential as mitigators for 5-FU-induced monocytopenia, cardiotoxicity, and other chemotherapy-associated disorders. Moreover, results show increased cytotoxicity against cancer cells compared to the drug, including a line with a drug resistance phenotype. Additionally, the ability of synthesized carriers to induce apoptosis and necrosis in treated CRC cells has been confirmed. Undoubtedly, the presented aspects of colorectal cancer therapy promise future solutions to overcome the conventional limitations of current treatment regimens for this type of cancer and to improve the quality of life of the patients.

Folate Receptor-Mediated Delivery of Cas9 RNP for Enhanced Immune Checkpoint Disruption in Cancer Cells

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system offers great opportunities for the treatment of numerous diseases by precise modification of the genome. The functional unit of the system is represented by Cas9/sgRNA ribonucleoproteins (RNP), which mediate sequence-specific cleavage of DNA. For therapeutic applications, efficient and cell-specific transport into target cells is essential. Here, Cas9 RNP nanocarriers are described, which are based on lipid-modified oligoamino amides and folic acid (FolA)-PEG to realize receptor-mediated uptake and gene editing in cancer cells. In vitro studies confirm strongly enhanced potency of receptor-mediated delivery, and the nanocarriers enable efficient knockout of GFP and two immune checkpoint genes, PD-L1 and PVR, at low nanomolar concentrations. Compared with non-targeted nanoparticles, FolA-modified nanocarriers achieve substantially higher gene editing including dual PD-L1/PVR gene disruption after injection into CT26 tumors in vivo. In the syngeneic mouse model, dual disruption of PD-L1 and PVR leads to CD8+ T cell recruitment and distinct CT26 tumor growth inhibition, clearly superior to the individual knockouts alone. The reported Cas9 RNP nanocarriers represent a versatile platform for potent and receptor-specific gene editing. In addition, the study demonstrates a promising strategy for cancer immunotherapy by permanent and combined immune checkpoint disruption.

A Novel Method of Magnetic Nanoparticles Functionalized with Anti-Folate Receptor Antibody and Methotrexate for Antibody Mediated Targeted Drug Delivery

Therapeutic effects of anticancer medicines can be improved by targeting the specific receptors on cancer cells. Folate receptor (FR) targeting with antibody (Ab) is an effective tool to deliver anticancer drugs to the cancer cell. In this research project, a novel formulation of targeting drug delivery was designed, and its anticancer effects were analyzed. Folic acid-conjugated magnetic nanoparticles (MNPs) were used for the purification of folate receptors through a novel magnetic affinity purification method. Antibodies against the folate receptors and methotrexate (MTX) were developed and characterized with enzyme-linked immunosorbent assay and Western blot. Targeting nanomedicines (MNP-MTX-FR Ab) were synthesized by engineering the MNP with methotrexate and anti-folate receptor antibody (anti-FR Ab). The cytotoxicity of nanomedicines on HeLa cells was analyzed by calculating the % age cell viability. A fluorescent study was performed with HeLa cells and tumor tissue sections to analyze the binding efficacy and intracellular tracking of synthesized nanomedicines. MNP-MTX-FR Ab demonstrated good cytotoxicity along all the nanocomposites, which confirms that the antibody-coated medicine possesses the potential affinity to destroy cancer cells in the targeted drug delivery process. Immunohistochemical approaches and fluorescent study further confirmed their uptake by FRs on the tumor cells' surface in antibody-mediated endocytosis. The current approach is a useful addition to targeted drug delivery for better management of cancer therapy along with immunotherapy in the future.

SI-ATRP Decoration of Magnetic Nanoparticles with PHEMA and Post-Polymerization Modification with Folic Acid for Tumor Cells' Specific Targeting

Targeted nanocarriers could reach new levels of drug delivery, bringing new tools for personalized medicine. It is known that cancer cells overexpress folate receptors on the cell surface compared to healthy cells, which could be used to create new nanocarriers with specific targeting moiety. In addition, magnetic nanoparticles can be guided under the influence of an external magnetic field in different areas of the body, allowing their precise localization. The main purpose of this paper was to decorate the surface of magnetic nanoparticles with poly(2-hydroxyethyl methacrylate) (PHEMA) by surface-initiated atomic transfer radical polymerization (SI-ATRP) followed by covalent bonding of folic acid to side groups of the polymer to create a high specificity magnetic nanocarrier with increased internalization capacity in tumor cells. The biocompatibility of the nanocarriers was demonstrated by testing them on the NHDF cell line and folate-dependent internalization capacity was tested on three tumor cell lines: MCF-7, HeLa and HepG2. It has also been shown that a higher concentration of folic acid covalently bound to the polymer leads to a higher internalization in tumor cells compared to healthy cells. Last but not least, magnetic resonance imaging was used to highlight the magnetic properties of the functionalized nanoparticles obtained.

Folic acid-doxorubicin polymeric nanocapsules: A promising formulation for the treatment of triple-negative breast cancer

Breast cancer is the most common cancers among women and is one of the main causes of morbidity and mortality in this population. In this study, we aimed to conjugate doxorubicin (DOX), a drug widely used in cancer chemotherapy, and folic acid (FA), a ligand targeted for cancer therapy, to lipid-core nanocapsules (LNC), and evaluate the efficacy of the nanoformulation against triple-negative breast cancer (TNBC) MDA-MB-231 cells that overexpress folate receptors (FRs). We performed cell viability assays, quantitative real-time PCR (qRT-PCR), cell migration assay, and clonogenic assay, as well as measured the levels of nitric oxide (NO) generated and cellular uptake. The results showed that the nanoformulation reduced cell viability. The results of qRT-PCR analysis revealed that the nanoformulation induced apoptosis of MDA-MB-231 cells. The mRNA expression levels of Cat and MnSod were increased when the nanoformulation was compared to the doxorubicin solution. Furthermore, the nanoformulation significantly decreased the migration of breast cancer cells in vitro and inhibited colony formation. Additionally, the expression of iNOS in MDA-MB-231 cells was higher when the nanoformulation was used compared to the doxorubicin solution. Cellular uptake was observed after incubating the MDA-MB-231 cells with the fluorescent-labeled nanoformulation. In conclusion, we developed a promising nanoformulation for the treatment of TNBC. Further studies are necessary to demonstrate the in vivo efficacy of this formulation.

The Interplay between Fe3O4 Superparamagnetic Nanoparticles, Sodium Butyrate, and Folic Acid for Intracellular Transport

Combined treatments which use nanoparticles and drugs could be a synergistic strategy for the treatment of a variety of cancers to overcome drug resistance, low efficacy, and high-dose-induced systemic toxicity. In this study, the effects on human colon adenocarcinoma cells of surface modified Fe₃O₄ magnetic nanoparticles (MNPs) in combination with sodium butyrate (NaBu), added as a free formulation, were examined demonstrating that the co-delivery produced a cytotoxic effect on malignant cells. Two different MNP coatings were investigated: a simple polyethylene glycol (PEG) layer and a mixed folic acid (FA) and PEG layer. Our results demonstrated that MNPs with FA (FA-PEG@MNPs) have a better cellular uptake than the ones without FA (PEG@MNPs), probably due to the presence of folate that acts as an activator of folate receptors (FRs) expression. However, in the presence of NaBu, the difference between the two types of MNPs was reduced. These similar behaviors for both MNPs likely occurred because of the differentiation induced by butyrate that increases the uptake of ferromagnetic nanoparticles. Moreover, we observed a strong decrease of cell viability in a NaBu dose-dependent manner. Taking into account these results, the cooperation of multifunctional MNPs with NaBu, taking into consideration the particular cancer-cell properties, can be a valuable tool for future cancer treatment.

New 55Co-labeled Albumin-Binding Folate Derivatives as Potential PET Agents for Folate Receptor Imaging

Overexpression of folate receptors (FRs) on different tumor types (e.g., ovarian, lung) make FRs attractive in vivo targets for directed diagnostic/therapeutic agents. Currently, no diagnostic agent suitable for positron emission tomography (PET) has been adopted for clinical FR imaging. In this work, two ⁵⁵Co-labeled albumin-binding folate derivatives-[⁵⁵Co]Co-cm10 and [⁵⁵Co]Co-rf42-with characteristics suitable for PET imaging have been developed and evaluated. High radiochemical yields (≥95%) and in vitro stabilities (≥93%) were achieved for both compounds, and cell assays demonstrated FR-mediated uptake. Both ⁵⁵Co-labeled folate conjugates demonstrated high tumor uptake of 17% injected activity per gram of tissue (IA/g) at 4 h in biodistribution studies performed in KB tumor-bearing mice. Renal uptake was similar to other albumin-binding folate derivatives, and liver uptake was lower than that of previously reported [⁶⁴Cu]Cu-rf42. Small animal PET/CT images confirmed the biodistribution results and showed the clear delineation of FR-expressing tumors.

Tumor-targeting photodynamic therapy based on folate-modified polydopamine nanoparticles

BACKGROUND

Photodynamic therapy (PDT), a clinical anticancer therapeutic modality, has a long history in clinical cancer treatments since the 1970s. However, PDT has not been widely used largely because of metabolic problems and off-target phototoxicities of the current clinical photosensitizers.

PURPOSE

The objective of the study is to develop a high-efficiency and high-specificity carrier to precisely deliver photosensitizers to tumor sites, aiming at addressing metabolic problems, as well as the systemic damages current clinical photosensitizers are known to cause.

METHODS

We synthesized a polydopamine (PDA)-based carrier with the modification of folic acid (FA), which is to target the overexpressed folate receptors on tumor surfaces. We used this carrier to load a cationic phthalocyanine-type photosensitizer (Pc) and generated a PDA-FA-Pc nanomedicine. We determined the antitumor effects and the specificity to tumor cell lines in vitro. In addition, we established human cancer-xenografted mice models to evaluate the tumor-targeting property and anticancer efficacies in vivo.

RESULTS

Our PDA-FA-Pc nanomedicine demonstrated a high stability in normal physiological conditions, however, could specifically release photosensitizers in acidic conditions, eg, tumor microenvironment and lysosomes in cancer cells. Additionally, PDA-FA-Pc nanomedicine demonstrated a much higher cellular uptake and phototoxicity in cancer cell lines than in healthy cell lines. Moreover, the in vivo imaging data indicated excellent tumor-targeting properties of PDA-FA-Pc nanomedicine in human cancer-xenografted mice. Lastly, PDA-FA-Pc nanomedicine was found to significantly suppress tumor growth within two human cancer-xenografted mice models.

CONCLUSION

Our current study not only demonstrates PDA-FA-Pc nanomedicine as a highly potent and specific anticancer agent, but also suggests a strategy to address the metabolic and specificity problems of clinical photosensitizers.

The synthesis and co-micellization of PCL-P(HEMA/HEMA-LA) and PCL-P(HEMA/HEMA-FA) as shell cross-linked drug carriers with target/redox properties

In order to obtain target/redox shell cross-linked micelles (TCM), copolymers poly(ε-caprolactone)-poly(2-hydroxyethyl methacrylate/methacrylate-alpha lipoic acid) and poly(ε-caprolactone)-poly(2-hydroxyethyl methacrylate/methacrylate-folate, PCL-P(HEMA/HEMA-LA) and PCL-P(HEMA/HEMA-FA) were designed and synthesized. The copolymers PCL-P(HEMA/HEMA-LA) could form reduction-sensitive cross-linked micelles (CM) by using a catalytic amount of DTT. The micelles maintained high stability against dilution but were destroyed in 10 mM dithiothreitol (DTT). The drug loaded content (DLC) of CM was 8.9%, which was almost twice as much as non-cross-linked micelle (NCM). In vitro drug release at pH 7.4 showed that the cumulative release rate of CM in 36 h was less than 30%, while it was about 50% for NCM. When PCL-P(HEMA/HEMA-LA) and PCL-P(HEMA/HEMA-FA) (FA 1%, 3% and 5%) formed target/redox micelles, IC50 of TCM with FA 3% was the lowest (1.4 µg/mL) to Hela cells with excessive expression folate receptors. The cell uptake of TCM by Hela cells is higher than target non-cross-linked micelles (TNCM), while there was not much difference between both micelles uptaken by A549 cells, which are lack of folate receptors. Therefore, the drug carriers of TCM have potential to be explored as shell cross-linked target/redox drug carriers to the cancer cells on the surface with excessive folate receptors.

Autistic traits and components of the folate metabolic system: an explorative analysis in the eastern Indian ASD subjects

Objectives: Proper metabolism of the folate is crucial for maintaining DNA integrity, chromosome structure, methylation, as well as gene expression, and thus, folate is speculated to contribute to the etiology of different disorders. Since the etiology of autism spectrum disorder (ASD) is believed to be influenced by both genetic and environmental factors, we hypothesized that functional single nucleotide polymorphisms (SNPs) affecting folate metabolic pathway may have a causal role in the etiology of ASD. Methods: We analyzed three SNPs, rs2071010, rs2298444 and rs1801198 (in the folate receptor 1, folate receptor 2 and transcobalamin 2, respectively), in 867 ethnically matched subjects including 206 ASD probands and 286 controls. Plasma vitamin B₆ and folate were measured in age-matched probands and controls. Results: ASD probands showed a higher frequency of rs2298444 'A' allele (P = 0.01) and genotypes with 'A' allele (P = 0.03) when compared with the controls. rs1801198 'C' allele and 'CG' genotype also showed higher occurrence in the probands (P = 0.009 and 0.005, respectively). Gender-based stratified analysis revealed a significant higher frequency of rs2298444 'A' allele (P = 0.003), genotypes with rs2298444 'A' allele (P = 0.003) and rs1801198 CG (P = 0.001) in the male probands. Studied variants also showed statistically significant associations with ASD-associated traits measured by the Childhood Autism Rating Scale. ASD subjects exhibited gross deficiency in vitamin B₆ level when compared with age-matched controls (P < 0.001), which correlated with risk genetic variants. Discussion: We infer from this pioneering study on eastern Indian subjects that vitamin B₆ deficiency, along with risk gene variants, may affect ASD-associated symptoms, warranting further investigation in large cohorts.

Mutations in folate transporter genes and risk for human myelomeningocele

The molecular mechanisms linking folate deficiency and neural tube defect (NTD) risk in offspring remain unclear. Folate transporters (SLC19A1, SLC46A1, SLC25A32, and FOLH1) and folate receptors (FOLR1, FOLR2, and FOLR3) are suggested to play essential roles in transporting folate from maternal intestinal lumen to the developing embryo. Loss of function variants in these genes may affect folate availability and contribute to NTD risk. This study examines whether variants within the folate transporter and receptor genes are associated with an increased risk for myelomeningocele (MM). Exons and their flanking intron sequences of 348 MM subjects were sequenced using the Sanger sequencing method and/or next generation sequencing to identify variants. Frequencies of alleles of single nucleotide polymorphisms (SNPs) in MM subjects were compared to those from ethnically matched reference populations to evaluate alleles' associated risk for MM. We identified eight novel variants in SLC19A1 and twelve novel variants in FOLR1, FOLR2, and FOLR3. Pathogenic variants include c.1265delG in SLC19A1 resulting in an early stop codon, four large insertion deletion variants in FOLR3, and a stop_gain variant in FOLR3. No new variants were identified in SLC46A1, SLC25A32, or FOLH1. In SLC19A1, c.80A>G (rs1051266) was not associated with our MM cohort; we did observe a variant allele G frequency of 61.7%, higher than previously reported in other NTD populations. In conclusion, we discovered novel loss of function variants in genes involved in folate transport in MM subjects. Our results support the growing evidence of associations between genes involved in folate transport and susceptibility to NTDs.

Evidence Favoring a Positive Feedback Loop for Physiologic Auto Upregulation of hnRNP-E1 during Prolonged Folate Deficiency in Human Placental Cells

Background: Previously, we determined that heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) functions as an intracellular physiologic sensor of folate deficiency. In this model, l-homocysteine, which accumulates intracellularly in proportion to the extent of folate deficiency, covalently binds to and thereby activates homocysteinylated hnRNP-E1 to interact with folate receptor-α mRNA; this high-affinity interaction triggers the translational upregulation of cell surface folate receptors, which enables cells to optimize folate uptake from the external milieu. However, integral to this model is the need for ongoing generation of hnRNP-E1 to replenish homocysteinylated hnRNP-E1 that is degraded.Objective: We searched for an interrelated physiologic mechanism that could also maintain the steady-state concentration of hnRNP-E1 during prolonged folate deficiency.Methods: A novel RNA-protein interaction was functionally characterized by using molecular and biochemical approaches in vitro and in vivo.Results: l-homocysteine triggered a dose-dependent high-affinity interaction between hnRNP-E1 and a 25-nucleotide cis element within the 5'-untranslated region of hnRNP-E1 mRNA; this led to a proportionate increase in these RNA-protein complexes, and translation of hnRNP-E1 both in vitro and within placental cells. Targeted perturbation of this RNA-protein interaction either by specific 25-nucleotide antisense oligonucleotides or mutation within this cis element or by small interfering RNA to hnRNP-E1 mRNA significantly reduced cellular biosynthesis of hnRNP-E1. Conversely, transfection of hnRNP-E1 mutant proteins that mimicked homocysteinylated hnRNP-E1 stimulated both cellular hnRNP-E1 and folate receptor biosynthesis. In addition, ferrous sulfate heptahydrate [iron(II)], which also binds hnRNP-E1, significantly perturbed this l-homocysteine-triggered RNA-protein interaction in a dose-dependent manner. Finally, folate deficiency induced dual upregulation of hnRNP-E1 and folate receptors in cultured human cells and tumor xenografts, and more selectively in various fetal tissues of folate-deficient dams.Conclusions: This novel positive feedback loop amplifies hnRNP-E1 during prolonged folate deficiency and thereby maximizes upregulation of folate receptors in order to restore folate homeostasis toward normalcy in placental cells. It will also functionally impact several other mRNAs of the nutrition-sensitive, folate-responsive posttranscriptional RNA operon that is orchestrated by homocysteinylated hnRNP-E1.

Rational Design of Targeted Next-Generation Carriers for Drug and Vaccine Delivery

Pattern recognition receptors on innate immune cells play an important role in guiding how cells interact with the rest of the organism and in determining the direction of the downstream immune response. Recent advances have elucidated the structure and function of these receptors, providing new opportunities for developing targeted drugs and vaccines to treat infections, cancers, and neurological disorders. C-type lectin receptors, Toll-like receptors, and folate receptors have attracted interest for their ability to endocytose their ligands or initiate signaling pathways that influence the immune response. Several novel technologies are being developed to engage these receptors, including recombinant antibodies, adoptive immunotherapy, and chemically modified antigens and drug delivery vehicles. These active targeting technologies will help address current challenges facing drug and vaccine delivery and lead to new tools to treat human diseases.

Modular Integration of Upconverting Nanocrystal-Dendrimer Composites for Folate Receptor-Specific NIR Imaging and Light-Triggered Drug Release

Upconversion nanocrystals (UCNs) display near-infrared (NIR)-responsive photoluminescent properties for NIR imaging and drug delivery. The development of effective strategies for UCN integration with other complementary nanostructures for targeting and drug conjugation is highly desirable. This study reports on a core/shell-based theranostic system designed by UCN integration with a folate (FA)-conjugated dendrimer for tumor targeting and with photocaged doxorubicin as a cytotoxic agent. Two types of UCNs (NaYF4:Yb/Er (or Yb/Tm); diameter = ≈50 to 54 nm) are described, each displaying distinct emission properties upon NIR (980 nm) excitation. The UCNs are surface modified through covalent attachment of photocaged doxorubicin (ONB-Dox) and a multivalent FA-conjugated polyamidoamine (PAMAM) dendrimer G5(FA)6 to prepare UCN@(ONB-Dox)(G5FA). Surface plasmon resonance experiments performed with G5(FA)6 dendrimer alone show nanomolar binding avidity (KD = 5.9 × 10(-9) M) to the folate binding protein. This dendrimer binding corresponds with selective binding and uptake of UCN@(ONB-Dox)(G5FA) by FAR-positive KB carcinoma cells in vitro. Furthermore, UCN@(ONB-Dox)(G5FA) treatment of FAR(+) KB cells inhibits cell growth in a light dependent manner. These results validate the utility of modularly integrated UCN-dendrimer nanocomposites for cell type specific NIR imaging and light-controlled drug release, thus serving as a new theranostic system.

High molecular weight chitosan derivative polymeric micelles encapsulating superparamagnetic iron oxide for tumor-targeted magnetic resonance imaging

Magnetic resonance imaging (MRI) contrast agents based on chitosan derivatives have great potential for diagnosing diseases. However, stable tumor-targeted MRI contrast agents using micelles prepared from high molecular weight chitosan derivatives are seldom reported. In this study, we developed a novel tumor-targeted MRI vehicle via superparamagnetic iron oxide nanoparticles (SPIONs) encapsulated in self-aggregating polymeric folate-conjugated N-palmitoyl chitosan (FAPLCS) micelles. The tumor-targeting ability of FAPLCS/SPIONs was demonstrated in vitro and in vivo. The results of dynamic light scattering experiments showed that the micelles had a relatively narrow size distribution (136.60±3.90 nm) and excellent stability. FAPLCS/SPIONs showed low cytotoxicity and excellent biocompatibility in cellular toxicity tests. Both in vitro and in vivo studies demonstrated that FAPLCS/SPIONs bound specifically to folate receptor-positive HeLa cells, and that FAPLCS/SPIONs accumulated predominantly in established HeLa-derived tumors in mice. The signal intensities of T2-weighted images in established HeLa-derived tumors were reduced dramatically after intravenous micelle administration. Our study indicates that FAPLCS/SPION micelles can potentially serve as safe and effective MRI contrast agents for detecting tumors that overexpress folate receptors.

Gefitinib loaded folate decorated bovine serum albumin conjugated carboxymethyl-beta-cyclodextrin nanoparticles enhance drug delivery and attenuate autophagy in folate receptor-positive cancer cells

BACKGROUND

Active targeting endocytosis mediated by the specific interaction between folic acid and its receptor has been a hotspot in biological therapy of many human cancers. Various studies have demonstrated that folate and its conjugates could facilitate the chemotherapeutic drug delivery into folate receptor (FR)-positive tumor cells in vitro and in vivo. In order to utilize FA-FR binding specificity to achieve targeted delivery of drugs into tumor cells, we prepared Gefitinib loaded folate decorated bovine serum albumin conjugated carboxymethyl-β-cyclodextrin nanoparticles for enhancing drug delivery in cancer cells. On this context, the aim of our study was to develop a novel nano-delivery system for promoting tumor-targeting drug delivery in folate receptor-positive Hela cells.

RESULTS

We prepared folic acid (FA)-decorated bovine serum albumin (BSA) conjugated carboxymethyl-β-cyclodextrin (CM-β-CD) nanoparticles (FA-BSA-CM-β-CD NPs) capable of entrapping a hydrophobic Gefitinib. It was observed that nanoparticles are monodisperse and spherical nanospheres with an average diameter of 90.2 nm and negative surface charge of -18.6 mV. FA-BSA-CM-β-CD NPs could greatly facilitate Gefitinib uptake and enhance the toxicity to folate receptor-positive Hela cells. Under the reaction between FA and FR, Gefitinib loaded FA-BSA-CM-β-CD NPs induced apoptosis of Hela cells through elevating the expression of caspase-3 and inhibited autophagy through decreasing the expressing of LC3. It also confirmed that clathrin-mediated endocytosis and macropinocytosis exerted great influence on the internalization of both NPs.

CONCLUSIONS

These results demonstrated that FA may be an effective targeting molecule and FA-BSA-CM-β-CD NPs provided a new strategy for the treatment of human cancer cells which over-expressed folate receptors.

Altered folate receptor 2 expression in uraemic patients on haemodialysis: implications for folate resistance

BACKGROUND

Folate therapy reduces, but does not normalize homocysteine (Hcy) levels, frequently elevated in chronic kidney disease (CKD). The mechanisms of this folate resistance are unknown. Cellular acquisition of folate is mediated by folate receptors (FRs), whose expression is also modulated by folate status, through an Hcy-dependent regulation mechanism involving heterogeneous nuclear ribonucleoprotein-E1 (hnRNP-E1). Our objective was to evaluate whether an alteration of the FR2 (the form present in nucleated blood cells) expression is present in CKD patients on haemodialysis (HD), and its susceptibility to folate treatment.

METHODS

A population of chronic uraemic patients on HD was enrolled, along with a control group, and studies on FR2 receptor expression and related items were performed in plasma and mononuclear cells from peripheral blood. A subgroup of patients was treated with methyltetrahydrofolate for 1 month.

RESULTS

In HD, there was a significant reduction in FR2 protein expression compared with controls, not correlated with Hcy concentrations, while its mRNA levels were significantly increased. After folate treatment, there was a significant mRNA decrease, in the absence of significant changes in receptor protein expression. hnRNP-E1 gene and protein expression levels increased pre-treatment, while decreased post-treatment.

CONCLUSIONS

In HD, FR2 expression is altered in peripheral mononuclear cells, since its levels are decreased and are not responsive to variations in Hcy concentration, while the intracellular machinery (receptor mRNA and hnRNP-E1), possibly triggering its regulation, is conserved. These findings provide insight into the mechanisms of folate resistance in uraemia.

Expression of folate receptors and heterogeneous nuclear ribonucleoprotein E1 in women with human papillomavirus mediated transformation of cervical tissue to cancer

AIMS

Folate receptors (FRs) mediate cellular uptake of folates in many cancer cells and in folate deficiency heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) mediates translational upregulation of FR in cultured cervical cancer cells. hnRNP-E1 can also interfere with human papillomavirus 16 (HPV-16) viral capsid protein synthesis (and thereby HPV proliferation) in vitro. This study aimed to evaluate prospectively the relevance of FR and hnRNP-E1 expression in the normal cervix, cervical dysplasia, and cancer.

METHODS

Cervical tissues from 12 women with normal histology and 69 consecutive women with varying grades of cervical dysplasia and cancer were prospectively evaluated for immunohistochemical expression of FR, hnRNP-E1, proliferating cell nuclear antigen (PCNA), and HPV. There were 22 women with low grade squamous intraepithelial lesions (LGSIL), 22 with high grade squamous intraepithelial lesions (HGSIL), and 25 with invasive cervical carcinoma.

RESULTS

Among normal subjects, 100% and 92% expressed hnRNP-E1 and FR, respectively. FR expression decreased from 91% in LGSIL to 68% and 64% in women with HGSIL and cancer, respectively. Similarly, hnRNP-E1 expression decreased from 86% in LGSIL to 68% and 40% in HGSIL and cancer, respectively. There was a highly significant positive correlation between the extent of FR and hnRNP-E1 expression, and an inverse correlation between HPV infection and hnRNP-E1 expression during progression of cervical dysplasia to cancer.

CONCLUSION

These results are consistent with a hypothesis that reduced hnRNP-E1 expression may be permissive for HPV proliferation and progression to cervical cancer, and support the need for prospective longitudinal studies of hnRNP-E1 expression in HPV-16 infected women.