Folic Acid Molecules Research Articles

Highly sensitive and specific cytosensing of HT 29 colorectal cancer cells using folic acid functionalized-KCC-1 nanoparticles

Functionalized fibrous nano-silica (KCC-1) was applied to specific electrochemical detection of HT 29 colorectal cancer cells based on folate (FA)/folate receptor (FR) interactions. KCC-1 fibrous materials were synthesized using a hydrothermal method and then functionalized with FA molecules to produce KCC-1-NH2-FA nanoparticles. The KCC-1-NH2-FA fibrous nanoparticles offer favorable bleaching stability and exceptional surface area–to–volume ratio which provide facility to design more sensitive cytosensors. The morphology, size and surface charge of KCC-1, KCC-1-NH2 and KCC-1-NH2-FA were approved by field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential, respectively. The porosity of the negatively charged KCC-1-NH2-FA was also tested with Brunauer-Emmett-Teller (BET) which approves the high surface area–to–volume ratio of the KCC-1 based materials. Flow cytometry and fluorescence imaging were applied to approve quantitative and qualitative attaching of KCC-1-NH2-FA to the HT 29 FR-positive cancer cells. Also, the specific capturing of the nanoparticles were approved by FR-negative HEK 293 normal cells as FR-negative cells through cellular uptake assay which showed the smart differentiation by KCC-1-NH2-FA nanomaterials. The cytotoxicity results revealed the biocompatible nature of KCC-1 based materials, implying that the developed method could be used in in vivo applications under the optimized conditions. The developed cytosensor response is linear from 50 to 1.2 × 104 cells/mL with a lower limit of detection (LLOQ) of 50 cells/mL. As advantage of the developed cytosensor is simple and provides excellent specificity and sensitivity which enables us to design point of care devices for clinical uses.

Multifunctional Oligonucleotide-Functionalized Conjugated Oligomer Nanoparticles for Targeted Cancer Cell Imaging and Therapy.

A novel and multifunctional oligonucleotide-functionalized conjugated oligomer nanoparticle (CON) is developed for effective cancer cell imaging and therapy by integration of fluorescence imaging, target recognition, photodynamic therapy (PDT), and chemotherapy. The CON itself possesses the high fluorescence emission efficiency for imaging and can generate reactive oxygen species for PDT. Due to its excellent biocompatibility, easy functional modification, and efficient drug loading and release ability, oligonucleotides enable the CON to be functionalized in many forms. For the target recognition, the CONs are functionalized with oligonucleotides labeled with folate molecules, which can specifically bind the CONs to the tumor cells overexpressing folate receptors. Moreover, the designed oligonucleotide on the CON hybridizes with its complementary sequence to form double-stranded DNA, which enables a sequence-specific loading with doxorubicin for chemotherapy. For different situations, the therapy of chemotherapy and PDT can be used solely or combinatorially. Therefore, this study provides a facile strategy for the multifunctional modification of CONs with oligonucleotides and opens a new avenue for targeted cell imaging and tumor treatment.

Abstract B013: Site specific conjugation of engineered non-native amino acids in an anti-CD3 Fab-folate bispecific antibody significantly enhances its antitumor properties in gynecologic cancers

Abstract Ovarian cancer is the seventh most commonly diagnosed cancer in women. Standard treatments typically include surgery followed by radiation and/or chemotherapy. However, currently 5-year survival rates are 44%, underlining the need for new effective therapies. The Folate receptor 1 (FOLR1, FRα) is expressed in 80% of ovarian tumors, making it an attractive target for CD3-based bispecific antibody therapies. Bispecific engagement of activated host T-cells in the tumor microenvironment is highly effective at eliminating tumor cells. We have developed an anti-CD3 Fab-folate bispecific antibody by engineering non-native amino acids (NNAAs) at a specific region within the Fab domain and conjugated a PEGylated folate molecule to these sites. Our data demonstrate that Ambrx’s proprietary site-specific conjugation technology provides significant advantages over non-PEGylated proteins. Citation Format: Michael J. Gray, Wisam Barkho, Barbara Tipton, Prathap Shastri, Hyun-Bae Jie, Jeff Steen, Rik Frank, Feng Tian, Dowdy Jackson, Shawn Zhang. Site specific conjugation of engineered non-native amino acids in an anti-CD3 Fab-folate bispecific antibody significantly enhances its antitumor properties in gynecologic cancers [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B013.

Renal Clearable Bi-Bi2S3 Heterostructure Nanoparticles for Targeting Cancer Theranostics.

Recent development of precise nanomedicine has aroused an overwhelming interest in integration of diagnosis and treatment for cancers. Designing renal-clearable and targeting nanoparticles (NPs) has specific cancer theranostic implications and remains a challenging task. In this work, the ultrasmall folic acid (FA) and bovine serum albumin-modified Bi-Bi2S3 heterostructure nanoparticles NPs (Bi-Bi2S3/BSA&FA NPs) with excellent computed tomography (CT) and photoacoustic imaging abilities and outstanding photothermal performances were synthesized in an aqueous phase route via a simple method. Bi-Bi2S3/BSA&FA NPs have the following criteria: (i) Bi-Bi2S3/BSA&FA NPs with heterostructure possess better stability than Bi NPs and higher Bi content than Bi2S3 NPs, which are conducive to the enhancement of CT imaging effect; (ii) Bi-Bi2S3/BSA&FA NPs with FA molecules on the surface could target the tumor site effectively; (iii) Bi-Bi2S3/BSA&FA NPs could inhibit tumor growth effectively under 808 nm laser irradiation; (iv) ultrasmall Bi-Bi2S3/BSA&FA NPs could be cleared through kidney and liver within a reasonable time, avoiding a long-term retention/toxicity. Therefore, the renal clearable Bi-Bi2S3/BSA&FA NPs are a promising agent for targeting cancer theranostics.

Amphiphilic Nanoaggregates with Bimodal MRI and Optical Properties Exhibiting Magnetic Field Dependent Switching from Positive to Negative Contrast Enhancement.

Mixed micelles based on amphiphilic gadolinium(III)-DOTA and europium(III)-DTPA complexes were synthesized and evaluated for their paramagnetic and optical properties as potential bimodal contrast agents. Amphiphilic folate molecule for targeting the folate receptor protein, which is commonly expressed on the surface of many human cancer cells, was used in the self-assembly process in order to create nanoaggregates with targeting properties. Both targeted and nontargeted nanoaggregates formed monodisperse micelles having distribution maxima of 10 nm. The micelles show characteristic europium(III) emission with quantum yields of 2% and 1.1% for the nontargeted and targeted micelles, respectively. Fluorescence microscopy using excitation at 405 nm and emission at 575-675 nm was employed to visualize the nanoaggregates in cultured HeLa cells. The uptake of folate-targeted and nontargeted micelles is already visible after 5 h of incubation and was characterized with the europium(III) emission, which is clearly observable in the cytoplasm of the cells. The very fast longitudinal relaxivity r1 of ca. 26 s-1 mM-1 per gadolinium(III) ion was observed for both micelles at 60 MHz and 310 K. Upon increasing the magnetic field to 300 MHz, the nanoaggregates exhibited a large switching to transversal relaxivity with r2 value of ca. 52 s-1 mM-1 at 310 K. Theoretical fitting of the 1H NMRD profiles indicate that the efficient T1 and T2 relaxations are sustained by the favorable magnetic and electron-configuration properties of the gadolinium(III) ion, rotational correlation time, and coordinated water molecule. These nanoaggregates could have versatile application as a positive contrast agent at the currently used magnetic imaging field strengths and a negative contrast agent in higher field applications, while at the same time offering the possibility for the loading of hydrophobic therapeutics or targeting molecules.

Rod in Tube: A Novel Nanoplatform for Highly Effective Chemo-Photothermal Combination Therapy toward Breast Cancer.

Gold nanorods (GNRs) and doxorubicin (DOX) were loaded into the lumen of halloysite nanotubes (HNTs) via a rapid synthesis process (2 min) and physical adsorption. The targeting molecules of folic acid (FA) are then conjugated to HNTs via reactions with bovine serum albumin (BSA). The formation of GNRs in HNTs was verified by different techniques. Au-HNT-DOX@BSA-FA shows a maximum temperature of 26.8 °C rising after 8 min of 808 nm laser irradiation under 0.8 W cm-2. The functionalized HNTs exhibited stronger chemotherapeutic effect under laser irradiation as the laser could promote the release of DOX and temperature rising. Au-HNT-DOX@BSA-FA-treated MCF-7 cells exhibited a survival rate of 7.4% after laser irradiation. Au-HNT-DOX@BSA-FA treatment does not induce obvious toxicity in blood biochemistry, liver, and kidney function in normal mice. In vivo chemo-photothermal treatment toward 4T1-bearing mice suggested that Au-HNT-DOX@BSA-FA exhibited remarkable tumor-targeted efficiency and good controlled release effect for DOX. Also, the nanoparticles exhibited a rapid photothermal performance and an ability to inhibit the growth of tumors. Because of the synergistic effect of chemical-photothermal therapy, the toxicity of DOX to normal tissues was reduced on the premise of ensuring the same curative effect with a low dosage of 0.32 mg kg-1. This novel chemo-photothermal therapy nanoplatform provided a safe, rapid, effective, and cheap choice for the treatment of breast tumors both in vitro and in vivo.

Conformational analysis and electronic structure of folic acid: A theoretical study

Folic acid decomposes when exposed to UV light so understanding of photochemical behavior of this biomolecule is very important. In this study, sixty conformers of folic acid were investigated by two methods of DFT calculations. The three most stable conformers were selected for study of their electronic structure and photoelectron spectra. The valence photoelectron spectra were simulated by two high level ab initio computational methods: general-R symmetry adapted cluster-configuration interaction (general-R-SAC-CI) method and outer-valence Green's function (OVGF). The SAC-CI computations were performed with two different basis sets: D95 (df,pd) and 6-311G(d,p). Because of the size of the folic acid molecule, OVGF calculations were only performed with 6-311G(d,p) basis set. The simulated photoelectron spectrum of folic acid was obtained by the superposition of weighted photoelectron spectra of individual conformers. natural bonding orbitals (NBO) calculations were performed for the assignment of simulated photoelectron spectra. The lowest energy ionizations occurs mostly from the orbitals localized on p-aminobenzoyl moiety in folic acid. Koopmans' approximation is only valid for describing the five lowest energy orbital ionizations (photoelectron bands). The in-situ molecular structures of two bio-active conformers were extracted from X-ray diffraction data obtained for folic acid bound to folate receptor protein. These molecular structures were then used for calculating ionization energies. We discuss the consequences for ligand-receptor binding of switching from the most stable conformation to bioactive conformation in FA.

Folic Acid Functionalized Zirconium-Based Metal-Organic Frameworks as Drug Carriers for Active Tumor-Targeted Drug Delivery.

Nanoscale metal-organic frameworks (NMOFs) have proven to be a class of promising drug carriers as a result of their high porosity, crystalline nature with definite structure information, and potential for further functionality. However, MOF-based drug carriers with active tumor-targeting function have not been extensively researched until now. Here we show a strategy for constructing active tumor-targeted NMOF drug carriers by anchoring functional folic acid (FA) molecules onto the metal clusters of NMOFs. Two zirconium-based MOFs, MOF-808 and NH2 -UiO-66, were chosen as models to reduce to the nanoscale for application as drug carriers, and then the terminal carboxylates of FA molecules were coordinated to Zr6 clusters on the surfaces of the nanoparticles by substitution of the original formate or terminal -OH ligands. The successful modification with FA was confirmed by solid-state 13 C MAS NMR and UV/Vis spectroscopy and other characterization methods. Drug loading and controlled release behavior at different pH were determined by utilizing the anticancer drug 5-fluorouracil (5-FU) as the model drug. Confocal laser scanning microscopy measurements further demonstrated that 5-FU-loaded FA-NMOFs have excellent targeting ability through the efficient cellular uptake of FA-NMOFs. This work opens up a new avenue to the construction of active tumor-targeted NMOF-based drug carriers with potential for cancer therapies.

Folate receptor-targeted liposomal nanocomplex for effective synergistic photothermal-chemotherapy of breast cancer in vivo.

An effective nanoparticle-based drug delivery platform holds great promise for non-invasive cancer therapy. This study explores the breast tumor regression in vivo by synergistic photothermal-chemotherapy based on liposomal nanocomplex (folic acid-gold nanorods-anticancer drug-liposome). The proposed liposomal nanocomplex can enhance the tumor targeting by functionalizing folic acid (FA) molecules on the surface of liposome that encapsulates both gold nanorods (AuNRs) and the doxorubicin (DOX) to combine the photothermal therapy and the chemotherapy, respectively. Herein, 7-nm gold nanorods were fabricated and co-encapsulated with DOX into nanoliposomes functionalized with FA, with an average diameter of 154 nm, for active targeting to the cancer cells. The experimental results showed that the FA targeting liposomes had better cellular uptake than the non-targeting liposomes (AuNRs-DOX-LPs). Especially, upon 5 min exposure to near infrared (NIR) irradiation (808 nm) triggered DOX release could be achieved to 46.38% in 60 min at pH 5.5. In addition, in vitro cell proliferation assays indicated that, with synergistic photothermal-chemotherapy, the targeting liposomes could significantly enhance the toxicity towards the cancer cells with the IC50 value of 1.90 ± 0.12 μg mL-1. Furthermore, in vivo experiments on the breast tumor-bearing mice showed that the targeting liposomes could effectively inhibit the growth of the tumors using the combined strategy.

The Distribution and Imaging of 99mTc-nGO-PEG-FA in Human Patu8988 Tumor-Bearing Nude Mice.

Background: To study the distribution and imaging of 99mTc-nGO-PEG-FA in human pancreatic cancer Patu8988 tumor-bearing nude mice, and to explore its usefulness as an imaging reagent for pancreatic cancer. Materials and Methods: Natural graphite powder was used as raw material to prepare the nanosized graphene oxide (nGO) by using the modified Hummers method, and then was covalently modified by polyethylene glycol (PEG) on the surface of nGO. The nGO was further optimized by in vitro cell experiment, and then conjugated with the targeting molecule folic acid (FA) to form nGO-PEG-FA system. The nGO-PEG-FA was finally labeled by radioactive nuclide 99mTc by direct labeling method to form the 99mTc-nGO-PEG-FA molecular imaging probe. Nude mice bearing patu8988 pancreatic cancer xenografts were intravenous injection (I.V.) injected with 99mTc-nGO-PEG-FA, and the distribution of 99mTc-nGO-PEG-FA in nude mice at different time course was investigated by determination of tissue uptake of radioactivity (%ID/g), as well as the single photon emission computed tomography (SPECT) imaging at different time course. Results: The labeling rate of nGO-PEG-FA with 99mTc was (90.08 ± 2.34)%, and the highest binding rate of 99mTc-nGO-PEG-FA with Patu8988 cells was (3.15 ± 0.31)%. The radioactive uptake in tumor reached (5.11 ± 1.23)%ID/g at 6 h after I.V. injection of 99mTc-nGO-PEG-FA in nude mice. Meanwhile, the radioactive uptake in liver, spleen, and lung was also high and reached (10.33 ± 1.22)%ID/g, (5.86 ± 0.59)%ID/g, and (3.55 ± 0.93)%ID/g, respectively, whereas less radioactivity uptake was observed in the heart (1.12 ± 0.33)%ID/g and blood (2.76 ± 0.39)%ID/g, respectively. The tumors can be clearly imaged at 4.0-6.0 h after 99mTc-nGO-PEG-FA injection. Conclusions: 99mTc-nGO-PEG-FA can efficiently target pancreatic cancer, which may be developed as an imaging agent for pancreatic cancer.

Biodegradable Nanoglobular Magnetic Resonance Imaging Contrast Agent Constructed with Host-Guest Self-Assembly for Tumor-Targeted Imaging.

Gadolinium-based macromolecular magnetic resonance imaging (MRI) contrast agents (CAs) have attracted increasing interest in tumor diagnosis. However, their practical application is potentially limited because the long-term retention of gadolinium ion in vivo will induce toxicity. Here, a nanoglobular MRI contrast agent (CA) PAMAM-PG- g-s-s-DOTA(Gd) + FA was designed and synthesized on the basis of the facile host-guest interaction between β-cyclodextrin and adamantane, which initiated the self-assembly of poly(glycerol) (PG) separately conjugated with gadolinium chelates by disulfide bonds and folic acid (FA) molecule onto the surface of poly(amidoamine) (PAMAM) dendrimer, finally realizing the biodegradability and targeting specificity. The nanoglobular CA has a higher longitudinal relaxivity ( r1) than commercial gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA), showing a value of 8.39 mM-1 s-1 at 0.5 T, and presents favorable biocompatibility on the observations of cytotoxicity and tissue toxicity. Furthermore, MRI on cells and tumor-bearing mice both demonstrate the obvious targeting specificity, on the basis of which the effective contrast enhancement at tumor location was obtained. In addition, this CA exhibits the ability of cleavage to form free small-molecule gadolinium chelates and can realize minimal gadolinium retention in main organs and tissues after tumor detection. These results suggest that the biodegradable nanoglobular PAMAM-PG- g-s-s-DOTA(Gd) + FA can be a safe and efficient MRI CA for tumor diagnosis.

An analysis of the interactions between folic acid and aromatic guest molecules.

The formation of complexes between folate and therapeutic drug molecules is well known. In this work, we attempted to elucidate the role of the aromatic rings of folate and drug molecules in interactions between both of these molecules. A detailed molecular simulation study was carried out to explore the associative behavior of folic acid with phenylalanine and tyrosine, which show fluorescence emission following the excitation of these molecules at 257nm and 274nm, respectively. Therefore, studies of fluorescence emission from phenylalanine and tyrosine were performed in this work. The results of these studies indicated that folic acid associates with phenylalanine and tyrosine with binding constants ranging from 1.46×104 to 2.66×104M-1. X-ray diffraction studies suggested that folic acid self-assembly is maintained in the presence of associative interactions of the folic acid with guest molecules. These results demonstrate that the aromatic rings in the structures of the folic acid and the therapeutic drug play an important role in the encapsulation of guest molecules through folate self-assembly.

Folic Acid-Functionalized Hybrid Photonic Barcodes for Capture and Release of Circulating Tumor Cells.

Recovery of circulating tumor cells (CTCs) from cancer patients by an efficient CTCs capture and release method can greatly increase their application in diagnostics and treatment of cancers. In this paper, we presented a folic acid (FA)-functionalized hybrid photonic barcode for capture and release of CTCs. The hybrid photonic barcodes were formed by two nano-ordered parts, poly(ethylene glycol) diacrylate (PEGDA) inverse opal structure for sustaining integrity and methacrylated gelatin (GelMA) gel filler for conjugating FA molecules to mediate cell capture. The nano-ordered structures of the hybrid photonic barcodes not only increased contact area, but also decreased steric hindrance among FA molecules. Thus, the topographic interaction between the barcodes and CTCs was greatly enhanced. In addition, GelMA gel was soft and extracellular matrix (ECM) alike, which was beneficial to decrease impairment to CTCs during the CTCs-barcode interaction as well as preserving their viability. Demonstrated by four CTCs types, Hela (epithelial tissue, folate receptor positive, FR+), A02 (bone marrow, FR+), Raji (lymphoid tissue, FR+), and A549 (epithelial tissue, folate receptor negative, FR-), FR+ CTCs could be captured efficiently with reliability and specificity. The captured cells could be controllably released with high viability just by quick trypsinization. The whole processes were simple and efficient. These features indicated that the FA-functionalized hybrid photonic barcodes were promising for full recovery of CTCs from cancer patients, which was important for diagnosis and treatment of cancer.

Reduced graphene oxide coated Cu2−xSe nanoparticles for targeted chemo-photothermal therapy

Recently, copper chalcogenide semiconductors have been reported as new near-infrared (NIR) photothermal agents. However, it is difficult to modify them with recognition molecules, and their photothermal conversion efficiencies are relatively low, making it difficult to achieve the targeted photothermal ablation of cancer cells with a high efficiency. In this study, reduced graphene oxide (rGO) was first coated on the surface of Cu2-xSe nanoparticles (NPs) to provide abundant functional groups for the next modification and to increase the photothermal conversion efficiency. Then, doxorubicin (DOX) was loaded and folic acid (FA) molecules were covalently linked onto the surface of Cu2−xSe/rGO nanocomposites. The formed DOX@Cu2−xSe@rGO-FA nanocomposites were successfully used as chemo-photothermal agents for the targeted killing of cancer cells by utilizing the recognition ability of FA, chemotherapy effect of DOX and photothermal effects of rGO and Cu2−xSe NPs. Under the 980-nm NIR laser irradiation, the nanocomposites showed significantly enhanced chemo-photothermal therapy effect, which can be potentially applied in the nanomedicine field.

Synthesis and Characterization of Folate Conjugated Boron Nitride Nanocarriers for Targeted Drug Delivery

We have developed advanced folate bonded to boron nitride (BN) nanocarriers with a high potential for targeted drug delivery. The folic acid (FA) molecules were successfully conjugated to BN nanoparticles (BNNPs) in three consecutive stages: (i) FA preactivation by N,N′-dicyclohexylcarbodiimide (DCC), (ii) BNNP modification by AgNPs and their further NH2-functionalization with l-cysteine, and (iii) final conjugation of activated FA to modified BNNPs. To shed light on the FA-BNNPs binding mechanism, detailed energetic analysis of the atomic structure and stability of the FA-BNNPs system using density functional theory (DFT) calculations was carried out. The results indicated that the FA was successfully bonded with the BNNPs by a condensation reaction between amino groups of Cyst-Ag/BNNPs and carboxyl groups of FA using DCC. Theoretical analysis also demonstrated that the grafting of FA to the surface of BNNP does not affect FA targeting properties.

Small amounts of ethanol attenuate folic acid stability in acidic beverages during storage.

Folic acid (FA) is an essential compound involved in important biochemical processes and is used to fortify various food products. FA in fortified acidic beverages decomposes during storage due to H+ attack. FA stability in acidic beverages is a serious problem as food fortification should guarantee labeled FA concentrations until the expiry date. In this study, we investigated the influence of ethanol (EtOH) on FA depletion using a model acidic beverage and observed that small amounts of EtOH, derived from added flavor, promoted FA depletion. FA depletion was promoted by only small amounts of EtOH, but not by acetonitrile. This suggested that FA decomposition might be accelerated by EtOH, which surrounds FA molecules in solution due to selective solvation. In the development of FA‐fortified beverages, EtOH content should be decreased or removed altogether, to prevent accelerating FA decomposition.

Design of folic acid based supramolecular hybrid gel with improved mechanical properties in NMP/H2O for dye adsorption

Folic acid (FA) supramolecular gel was prepared in a mixture solvent of N-methylpyrrolidone (NMP)/H2O at a 1/1 volume ratio by using FA as gelator with a concentration of 0.4% (w/v). In the mixture solvent, NMP was first of time used as a good solvent to tune the solvent properties in order to be able to induce formation of FA supramolecular gel. The folic acid-gelatin (FA-GA) hybrid gels were synthesized by adding different amount of gelatin (GA) into FA gelator. The gelation temperature (TGel) of the FA-GA hybrid gel is 30°C which is much higher than that of FA gel (10°C). The gel to sol transition temperature (TGS) is about 58°C, which demonstrates that the hybrid gel has good stability at room temperature. The FT-IR and UV–vis spectra of FA-GA hybrid gel indicate that GA involves in the self-assembly process of FA via hydrogen bonding and π-π interactions with FA molecules. Owing to the π-π interaction happened between FA and GA molecules the fluorescence intensity of FA-GA gel is four times as high as that of FA gel. SEM images shows that the hybrid gel has a helical-fiber network structure which would enhance the gel strength to a great extent. Good stability, large specific surface and porosity in three-dimensional network structure of the FA-GA hybrid gel make it a highly promising adsorbent for dye adsorption. The FA-GA hybrid gel is able to absorb 63.5% of Congo red (CR), 68% of methyl blue (MB) and 44% of methyl orange (MO) respectively from their solutions.

Acid-activatable doxorubicin prodrug micelles with folate-targeted and ultra-high drug loading features for efficient antitumor drug delivery

Stimuli-responsive nanomedicine shows high therapeutic effects and low side effects to tumor cells and tissues, representing a preferable therapeutics for cancer therapy. Herein, we design an acid-stimuli-responsive doxorubicin polymeric prodrug (OM@DOX), and this amphiphilic prodrug has a unique chemical structure with prominent advantages, including high drug loading rate (as high as 61.5 wt%), pH-triggered drug release and targeted access to cells. This smart polymeric prodrug has a preferable size of ~40 nm and strong micellar stability in aqueous solution, which is benefited to the long blood circulation and efficient extravasation from tumor vessel. Moreover, the prodrug micelles showed a higher cytotoxicity against tumor cells (HeLa cells) than normal cells (L929 cells), likely suggesting the potential tumor-specific targeting ability. To render this prodrug micelles with targeting function, folic acid (FA) molecules conjugated prodrug (FA-OM@DOX) further showed selectively higher cytotoxicity to KB tumor cells (FA-receptor-positive) than A549 tumor cells (FA-receptor-negative). Considering the rapidly cell-penetrating ability and aforementioned features, we believe that the present prodrug strategy has the potential as a promising nanomedicine and providing inspired insights to design multifunctional drug delivery nanoplatforms.

Laser Desorption Postionization Mass Spectrometry Imaging of Folic Acid Molecules in Tumor Tissue.

Mass spectrometry imaging (MSI) is an innovative and powerful tool in biomedical research. It is well-known that folic acid (FA) has a high affinity for folic acid receptor (FR), which is overexpressing in epithelial cancer. Herein, we propose a novel method to diagnose cancer through direct mapping of the label-free FA spatial distribution in tissue sections by state-of-the-art laser desorption postionization-mass spectrometry imaging (LDPI-MSI). Compared with other tumor imaging methods, such as fluorescence imaging, photoacoustic imaging (PAI), magnetic resonance imaging (MRI), and micro-SPECT/CT, complicated synthesis and labeling processes are not required. The LDPI-MSI was performed on 30 μm thick sections from a murine model of breast cancer (inoculation of 4T1 cells) that were predosed with 20 mg/kg of FA. The image obtained from the characteristic mass spectrometric signature of FA at m/z 265 illustrated that FA was concentrated primarily in tumor tissue and displayed somewhat lower retention in adjacent normal controls. The results suggest that the proposed method could be used potentially in cancer diagnosis.

Phase 1 dose escalation study of the folate receptor-targeted small molecule drug conjugate EC1456.

2576 Background: The folate receptor (FR) is highly expressed in a variety of cancers including adenocarcinoma of the lung, but is expressed at low levels in most normal tissues, making it a potential target for therapeutic intervention. EC1456 is an FR-targeted small molecule drug conjugate (SMDC) consisting of folic acid chemically attached through a bio-releasable linker system to a potent microtubule inhibitor, tubulysin B hydrazide (TubBH). EC1456 binds to, and is endocytosed by the FR-expressing cancer cell to deliver TubBH. Following endocytosis, the FR recycles back to the membrane surface every 18-24 hours. Therefore alternative EC1456 schedules will be evaluated for safety, pharmacokinetics, and therapeutic benefit. Methods: Part A (dose escalation) is being evaluated in unselected patients (pts) with advanced solid tumors. 4 schedules (3-week cycle) are being evaluated: BIW (twice weekly); QW (once weekly); CWD (continuously weekly); QIW (four times a week). The primary objective of Part A is to determine the RP2 dose and schedule of EC1456. Part B (expansion) will confirm the MTD and RP2 dose and evaluate efficacy of EC1456 in 99mTc-etarfolatide-selected NSCLC patients in up to three schedules. Results: 74 Part A pts are evaluable for toxicity. Median age is 68 (range: 26-88); 53 pts are female. Toxicities are primarily Grade (Gr) 1 and 2. Common treatment-related adverse events (TRAE) are gastrointestinal, fatigue, metabolic changes, alopecia, and headache. 5 Gr 3 DLTs have been observed: infusion reaction (4.5 mg/m2 QW), headache (10.0 mg/m2 QW), and abdominal pain (7.5 mg/m2 BIW, 12.5 mg/m2 QW and 10.0 mg/m2CWD). TRAEs are summarized in the table for each schedule. Durable stable disease of 12 wks or longer has been observed in 12 pts (6 BIW and 6 QW). Conclusions: All Part A EC1456 schedules have been well tolerated. RP2 dose for BIW is 6.0 mg/m2 and QW is 12.5 mg/m2; dose escalation is ongoing for CWD and QIW. Early signs of efficacy in an unselected pt population may be suggested by durable stable disease. Safety and efficacy evaluation in the 99mTc-etarfolatide-selected NSCLC population (Part B) is ongoing. Clinical trial information: NCT01999738. [Table: see text]