Levels Of Folate Receptor Expression Research Articles

Appraisal of folate functionalized bosutinib cubosomes against hepatic cancer cells: In-vitro, In-silico, and in-vivo pharmacokinetic study

Targeted therapies enhance the efficacy of tumour screening and management while lowering side effects. Multiple tumours, including liver cancer, exhibit elevated levels of folate receptor expression. This research attempted to develop surface-functionalised bosutinib cubosomes against hepatocellular carcinoma. The novelty of this work is the anti-hepatic action of bosutinib (BST) and folic acid-modified bosutinib cubosomes (BSTMF) established through proto-oncogene tyrosine-protein kinase (SrC)/ focal adhesion kinase(FAK), reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and cell cytotoxicity. Later, the in-vivo pharmacokinetics of BSTMF were determined for the first time. The strong affinity of folic acid (FA) for folate receptors allows BSTMF to enter cells via FA receptor-mediated endocytosis. The particle size of the prepared BSTMF was 188.5 ± 2.25 nm, and its zeta potential was −20.19 ± 2.01 mV, an encapsulation efficiency of 90.31 ± 3.15 %, and a drug release rate of 76.70 ± 2.10 % for 48 h. The surface architecture of BSTMF was identified using transmission electron microscopy (TEM) and Atomic force microscopy (AFM). Cell-line studies demonstrated that BSTMF substantially lowered the viability of Hep G2 cells compared to BST and bosutinib-loaded cubosomes (BSTF). BSTMF demonstrated an elevated BST concentration in tumour tissue than in other organs and also displayed superior pharmacokinetics, implying that they hold potential against hepatic cancers. This is the first study to show that BSTMF may be effective against liver cancer by targeting folate receptors and triggering SrC/FAK-dependent apoptotic pathways. Multiple parameters demonstrated that BSTMF enhanced anticancer targeting, therapeutic efficacy, and safety in NDEA-induced hepatocellular carcinoma.

Anti-tumor Effect of Folate-Binding Protein: In Vitro and In Vivo Studies.

Folate receptor (FR) overexpression in a wide range of solid tumors provides an opportunity to develop novel, targeted cancer therapeutics. In this study, we investigated whether prebinding the chemotherapeutic methotrexate (MTX) to folate-binding protein (FBP), the soluble form of FR, would enable the protein to serve as a targeted therapeutic vector, enhancing uptake into tumor cells and improving therapeutic efficacy. In an in vivo study, using an FR-overexpressing KB xenograft model in SCID mice, modest improvement in inhibiting tumor growth was observed for the MTX/FBP mixtures as compared to saline control and free MTX. Surprisingly, FBP alone inhibited tumor growth compared to saline control, free MTX, and FBP/MTX. In order to better understand this effect, we investigated the cytotoxicity of micromolar concentrations of FBP in vitro using the KB, HeLa, and A549 cancer cell lines. Our results revealed concentration-dependent apoptosis (24 h; 10-50 μM) in all three cell lines accompanied by a time- and concentration-dependent reduction (6, 12, and 24 h; 10-50 μM) in metabolic activity and compromised cell plasma membrane integrity. This study demonstrates an apoptosis pathway for cytotoxicity of FBP, an endogenous serum protein, in cancer cell lines with widely varying levels of FR expression. Furthermore, in vivo tumor growth suppression for xenograft KB tumors in SCID mice was observed. These studies suggest novel strategies for the elimination of cancer cells employing endogenous, serum transport proteins.

Co‐Delivery of Paclitaxel and shMCL‐1 by Folic Acid‐Modified Nonviral Vector to Overcome Cancer Chemotherapy Resistance

Acquired chemoresistance presents a major clinical impediment, which is an urgent problem to be solved. Interestingly, myeloma cell leukemia-1 (MCL-1) and folate receptor expression levels are higher in chemotherapy-resistant patients than in pretreatment patients. In this study, a multifunctional folic acid (FA)-targeting core-shell structure is presented for simultaneous delivery of shMCL-1 and paclitaxel (PTX). The transfection efficiency of shMCL-1 with the FA-targeting delivery system is higher than with a nontargeting delivery system in Skov3 and A2780T cells. The FA-targeting system significantly inhibits cell growth, blocks cell cycles, and promotes apoptosis of cancer cells in vitro. The mechanisms involved in inhibiting growth are related to Bcl-2/Bax and cdc2/Cyclin B1 pathways. An analysis of RNA sequencing suggests that shMCL-1 reverses chemoresistance through regulating genes such as regulator of chromosome condensation 2 (RCC2). The synergetic effect of shMCL-1 and PTX effectively inhibits tumor growth in both PTX-resistant and normal cancer models by inducing tumor apoptosis, inhibiting proliferation, and limiting tumor angiogenesis. The study results indicate that a FA-targeting delivery system combining shMCL-1 with PTX can simultaneously target tumor sites and restore the sensitivity of chemotherapy-resistant cancer to PTX. These findings have important implications for patients with normal or PTX-resistant cancer.

58P - IKS01, a next generation antibody drug conjugate (ADC) designed to be efficacious in tumors with low and moderate levels of folate receptor expression

BackgroundFrequent over-expression of FRA in ovarian and non-small-cell lung cancer (NSCLC), and relative lack of expression in normal tissue, make it an attractive therapeutic target. Ovarian cancer is the ninth most common cancer in women and the leading cause of death in gynaecological cancer. Lung cancer remains a leading cause of cancer-related death with NSCLC accounting for 80 % of cases. ADCs are the focus of intense interest as a means to provide selective tumor killing with increased efficacy and less off-target toxicity than standard of care chemotherapies. Clinical evaluation of mirvetuximab soravtansine in solid tumor indications demonstrated that FRA can be successfully targeted by an ADC. However, anti-tumor activity appears to be generally limited to patients whose tumors express high levels of FRA. IKS01 is an ADC comprised of an FRA-targeting antibody conjugated via Iksuda’s PermaLink conjugation technology to Femtogenix’s highly potent FGX2-62 payload. FGX2-62 is a pyrridinobenzodiazepine DNA mono-alkylating agent with pM potency in a range of tumor cell lines. IKS01 has been designed to be sufficiently potent to have target-dependent efficacy even in tumors with low or moderate expression of the target antigen. MethodsIKS01 was generated with a drug to antibody ratio of 2. Efficacy was evaluated in human cell line derived xenograft models with a range of FRA expression, including the choriocarcinoma Jeg-3 model (high expression), the ovarian adenocarcinoma OV-90 model (low expression) and the lung adenocarcinoma NCI-H2110 model (moderate expression). An FRA-targeting benchmark ADC with a format that has shown clinical efficacy was included for comparison. ResultsIKS01 is highly effective in causing tumor regressions in FRA-expressing tumor models at doses that are well tolerated. IKS01 was significantly more active than benchmark ADC in the high FRA-expressing Jeg-3 model and caused complete or near complete regressions in low/moderate FRA-expressing xenograft models where the benchmark ADC showed limited or no activity. ConclusionsIKS01 shows marked anti-tumor efficacy in pre-clinical models of ovarian and lung cancer, even in models with low or moderate FRA expression. Legal entity responsible for the studyIksuda Therapeutics Ltd. FundingIksuda Therapeutics Ltd. DisclosureJ. Thirlway: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd. A. Lodge: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd. A. Pelava: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd. D.J. Williamson: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd. D. Carta: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd. M. Al Nakeeb: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd. J. Mysliwy: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd. P.J.M. Jackson: Shareholder/Stockholder/Stock options: Femtogenix Ltd. D.E. Thurston: Shareholder/Stockholder/Stock options: Femtogenix Ltd. R.J. Lutz: Shareholder/Stockholder/Stock options: Iksuda Therapeutics Ltd.

Cancer‐Targeting Graphene Quantum Dots: Fluorescence Quantum Yields, Stability, and Cell Selectivity

AbstractFolic acid, due to its high affinity toward folate receptors (FR), is recognized as one of the most promising cancer targeting vectors. However, the inherent defects of low water solubility (1.6 µg mL−1), high sensitivity toward photo‐bleaching, low fluorescent quantum yields (QYs, <0.5%) seriously limit its practical application. Herein, ultrastable, highly luminescent graphene quantum dots (GQDs) that selectively target diverse cancer cells are prepared and tested. The new GQDs present step changes compared to common folic acid through an ≈6250 times increase in water solubility (to ≈10 mg mL−1), more than 150 times in QYs (up to ≈77%), while maintaining luminescence stability up to 98% when subjected to UV, visible light, and heating over 360 min. It is shown that the suppression of nonradiative transitions by amino groups pyrolyzed from pterin plays a key role in the mechanism of high QYs and excellent stability. The functional groups that are likely responsible for the selective targeting of cancer cells with different levels of folate receptor expression on the surface are identified. Collectively with these promising properties, the new functional graphene quantum dots may open a new avenue for cancer diagnosis, drug delivery, and therapies.

Reversal of drug resistance by planetary ball milled (PBM) nanoparticle loaded with resveratrol and docetaxel in prostate cancer

The folate receptor (FR) is a valued target that is highly expressed in various cancers, which will expedite the development of ligand-receptor binding based cancer therapeutics. In the present investigation, through tissue microarray analysis, we report higher levels of folate receptor expression in prostate cancer (PCa) tissue derived from patients, which were minimal in normal tissue. For folate-receptor based targeted therapy of PCa, we generated novel planetary ball milled (PBM) nanoparticles (NPs) encapsulated with resveratrol (RES), and in combination with docetaxel (DTX) and conjugated with folic acid (FA) on the surface. The cytotoxic effect of FA-conjugated DTX-nanoparticles was found effectual that reduced the concentration of free drug (DTX) to 28 times. Flow cytometry analysis showed a significant increase in the number of apoptotic cells by 30.92% and 65.9% in the FA-conjugated RES and in combination with DTX nanoparticle formulation respectively. However, only 8.9% apoptotic cells were found with control (empty NP). The expressions of NF-kB p65, COX-2, pro (BAX, BAK) and anti-apoptotic (BCL-2, BCL-XL) genes were significantly reduced after treatment with FA-RES + DTX-NP. In addition, the FA-conjugated DTX formulation exhibited additional cytotoxic effects with the down-regulation of survivin and an increased expression of Cleaved Caspase-3 in PCa cells. Further, we observed that treating DTX resistant PCa cells with FA-RES + DTX-NP exhibited a reversal of the ABC-transporter markers thereby limiting the multidrug resistance phenotype of the cancer cells. Our results strongly suggested that FA conjugated nanoparticle drugs acted as effective inhibitors of drug efflux that effectually enhances the intracellular concentration of the drug to exhibit their cytotoxic effect.

Design and optimization of novel paclitaxel-loaded folate-conjugated amphiphilic cyclodextrin nanoparticles

As nanomedicines are gaining momentum in the therapy of cancer, new biomaterials emerge as alternative platforms for the delivery of anticancer drugs with bioavailability problems. In this study, two novel amphiphilic cyclodextrins (FCD-1 and FCD-2) conjugated with folate group to enable active targeting to folate positive breast tumors were introduced. The objective of this study was to develop and characterize new folated-CD nanoparticles via 32 factorial design for optimal final parameters. Full physicochemical characterization studies were performed. Blank and paclitaxel loaded FCD-1 and FCD-2 nanoparticles remained within the range of 70–275nm and 125–185nm, respectively. Zeta potential values were neutral and −20mV for FCD-1 and FCD-2 nanoparticles, respectively. Drug release studies showed initial burst release followed by a longer sustained release. Blank nanoparticles had no cytotoxicity against L929 cells. T-47D and ZR-75-1 human breast cancer cells with different levels of folate receptor expression were used to assess anti-cancer efficacy. Through targeting the folate receptor, these nanoparticles were efficiently engulfed by the breast cancer cells. Additionally, breast cancer cells became more sensitive to cytotoxic and/or cytostatic effects of PCX delivered by FCD-1 and FCD-2. In conclusion, these novel folate-conjugated cyclodextrin nanoparticles can therefore be considered as promising alternative systems for safe and effective delivery of paclitaxel with a folate-dependent mechanism.

Characterization and evaluation of a folic acid receptor-targeted cyclodextrin complex as an anticancer drug delivery system

To improve the water solubility and tumor targeting ability of docetaxel (DTX), and thus enhance the drug's antitumor efficacy and safety, a novel folate receptor (FR)-targeted cyclodextrin drug delivery vehicle (FA-CD) was successfully synthesized. The synthesis of the designed cyclodextrin was confirmed by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), and differential scanning calorimetry (DSC). The in vitro cytotoxicity was investigated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the results showed that no significant differences (p>0.05) appeared in cytotoxicity between the different cyclodextrins in the different cell lines. Besides, the DTX/FA-CD inclusion complex was prepared. The cellular uptake and competition assays were examined using the HepG2, HeLa, and KB cell lines, which have different levels of folate receptor expression. Interestingly, the Cy5.5/FA-CD complex had higher uptake in the HepG2, HeLa, and KB cells, compared with non-targeted Cy5.5/CD complex (p<0.001). The time-dependent drug uptake into KB cells observed by LSCM confirmed the drug delivery via endocytic routes. Data from the competition assays, especially in KB cells, showed that a significant inhibitory effect (p<0.001) was obtained when the concentration of FA was increased, and suggested that the Cy5.5/FA-CD was internalized through a FR-mediated mechanism. Moreover, the in vitro bioactivity assay also demonstrated efficient antitumor activity, and the order of the cell viabilities (% of control) was OB>HepG2>HeLa>KB for DTX/FA-CD (p<0.001). For DTX/CD, however, it displayed minimum antitumor behavior in all cell types. An apoptosis study by FCM and LSCM also revealed that the FA-modified complexes were more effective in inducing apoptosis in FR-expressing cells. Finally, an in vivo biodistribution study in KB-bearing healthy mice revealed that the DTX/FA-CD complex has enhanced tumor-targeting efficacy and diminished systemic side effects. These results suggest that the novel FR-targeted cyclodextrin complex is a promising alternative as an anticancer drug delivery system.

Label-free quartz crystal microbalance with dissipation monitoring of resveratrol effect on mechanical changes and folate receptor expression levels of living MCF-7 cells: a model for screening of drugs.

Quartz crystal microbalance with dissipation (QCM-D) monitoring was used for real-time and label-free detection of changes and folate receptor (FR) expression levels on living MCF-7 cells for evaluating the anticancer activity of resveratrol. Here, the mechanical changes of cellular responses to resveratrol were tracked by a poly(l-lysine) (PLL) modified QCM-D sensor, and the inhibition effect of resveratrol on FR expression levels on MCF-7 cells was monitored by chitosan-folic acid (CS-FA) composite membrane functionalized Au substrate for the first time. Changes in morphology and the cellular state of MCF-7 cells stimulated by resveratrol at different concentrations were detected by inverted fluorescence microscopy and flow cytometry. Atomic force microscopy confirmed that resveratrol influenced the cellular mechanical properties. The results indicated that the MCF-7 cells lose their original elasticity and increase their stiffness induced by resveratrol. It was further observed by confocal fluorescence imaging that resveratrol reduced the FR expression levels on the living cells surface. This study established a typical model of the QCM-D biosensor to evaluate the protein biomarker expression levels on the cells surface. QCM-D, which was used to investigate potential targets for an antitumor drug on living cells and realize a better understanding of the drug action mechanism, was expected to be developed into a promising tool for the screening of drugs.

Examining expression of folate receptor in squamous cell carcinoma of the head and neck as a target for a novel nanotherapeutic drug.

Nanotechnology-based drug delivery approaches may help increase therapeutic efficacy and decrease side effects of chemotherapeutics. We investigated expression levels of folate receptor in squamous cell carcinoma of the head and neck (SCCHN) to evaluate folate receptor as a target for nanotherapy. Folate receptor expression levels in archival SCCHN tissues were analyzed by immunohistochemistry and correlated with clinical parameters. Folate receptor was detected in 45% of primary tumors and 40% of corresponding lymph node metastases. Folate receptor expression in primary tumors of the metastatic group strongly correlated with the corresponding lymph node metastases (p = .0002). Folate receptor expression was inversely correlated with disease-free survival in nonmetastatic (p = .0048), metastatic (p = .0127), and lymph node metastases (p <.001) groups, and with overall survival in the lymph node metastases group (p <.0001). Folate receptor is expressed in a significant proportion of primary SCCHN and corresponding lymph node metastases tissues, and correlates with worse clinical outcome. These findings provide support for folate receptor-mediated nanotherapeutics in SCCHN.

Biological characterization of folic acid-conjugated poly(H2NPEGCA-co-HDCA) nanoparticles in cellular models

The folate receptor (FR) is a highly selective tumor marker over expressed in many human cancers and it constitutes a useful target for tumor-specific drug delivery. Thus, the conjugation of folic acid to different drugs or drug carriers may enhance the delivery of the therapeutic agent to FR-positive tumor cells. The aim of this study was to investigate the interactions of folate-conjugated polyalkylcyanoacrylate nanoparticles with tumor cells overexpressing the FR. For this purpose, nanoparticles were prepared by nanoprecipitation of the poly[aminopoly(ethylene glycol) cyanoacrylate-co-hexadecyl cyanoacrylate] [poly(H2NPEGCA-co-HDCA)] copolymer and labeled with the hydrophobic fluorescent dye nile red. Nile red-loaded nanoparticles were then conjugated to folic acid via the PEG terminal amino groups. Four human cancer cell lines were then tested by western blot in order to evaluate the FR expression levels. KB3-1 cell line showed the higher expression level, while MCF-7 cells were taken as a control. After measuring the cytotoxicity of the nanoparticles on these two cell lines, fluorescent folate-nanoparticles were incubated with them and the cellular uptake was evaluated by confocal microscopy and flow cytometry. KB3-1 cells showed a greater nanoparticle internalization, when compared to MCF-7 cells.

In vitro and in vivo targeting of different folate receptor-positive cancer cell lines with a novel 99mTc-radiofolate tracer

For the assessment of folate-based radiopharmaceuticals, human nasopharyngeal KB carcinoma cells are traditionally used although nasopharyngeal cancer is rare. On the other hand, the folate receptor (FR) is frequently overexpressed on diverse cancer types, the highest frequency (>90%) being on ovarian carcinomas. The goal of our study was the in vitro and in vivo assessment of different FR-positive human carcinoma cells. In addition, a murine sarcoma cell line was assessed as a pre-clinical alternative to human xenograft models. FR-positive human nasopharyngeal, cervical, ovarian and colorectal cancer cell lines and the transgenic mouse sarcoma (24JK-FBP) cell line were targeted with a novel 99mTc-tricarbonyl folate derivative 2. Comparative in vitro cell binding studies were carried out under standardised folate-deficient conditions. In vivo studies were performed in nude mice and C6 black mice. The in vitro cell experiments revealed only FR-specific binding (unspecific <0.02%), ranging from 3.5% to 52% of complex 2 owing to variable levels of FR expression of the cell lines. In vivo tumour uptake of radiotracer 2 varied less than in vitro. It ranged from 0.66+/-0.17% ID/g (LoVo) through 1.16+/-0.64% ID/g (IGROV-1) and 1.55+/-0.43% ID/g (24JK-FBP) to 2.33+/-0.36% ID/g (KB) 4 h p.i. These pre-clinical studies indicate that in vitro data obtained in FR-positive cancer cells do not necessarily correspond with or predict in vivo radiofolate uptake in corresponding (xeno)grafts. In addition, the murine 24JK-FBP cell line proved to be a valuable pre-clinical alternative to human tumour models.

Folate receptor expression in carcinomas and normal tissues determined by a quantitative radioligand binding assay

The folate receptor (FR) is a valuable therapeutic target that is highly expressed on a variety of cancers. The current development of folate-targeted cancer therapies has created the need for quantitating functional FRs in clinical specimens. In this article, we report on the creation of a highly sensitive radioactive binding method for quantitatively measuring FR expression in frozen tissue homogenates. Expression was positive in approximately 89% of human ovarian carcinomas but was negligible in both mucinous ovarian carcinomas and normal ovary. Expression was also significant in carcinomas of the kidney, endometrium, lung, breast, bladder, and pancreas. Normal tissues from humans and six different laboratory species were also analyzed; surprisingly, some interspecies variability in FR expression (especially in kidney, spleen, and lung tissue) was found. Interestingly, normal human lung tissue displayed high expression levels, whereas expression in normal lung of the other species was negligible. However, considering that folate–drug conjugates fail to accumulate in the lungs of patients, the consequence of this finding was not considered to be of clinical concern. Overall, this new methodology is reliable for determining functional FR expression levels in tissues, and it could possibly be a useful clinical test to determine patient candidacy for FR-targeted therapeutics.