Folate Targeting Research Articles

Targeting Folate Metabolism Is Selectively Cytotoxic to Glioma Stem Cells and Effectively Cooperates with Differentiation Therapy to Eliminate Tumor-Initiating Cells in Glioma Xenografts.

Glioblastoma (GBM) is one of the deadliest of all human cancers. Developing therapies targeting GBM cancer stem cells or glioma stem cells (GSCs), which are deemed responsible for the malignancy of GBM due to their therapy resistance and tumor-initiating capacity, is considered key to improving the dismal prognosis of GBM patients. In this study, we found that folate antagonists, such as methotrexate (MTX) and pemetrexed, are selectively cytotoxic to GSCs, but not to their differentiated counterparts, normal fibroblasts, or neural stem cells in vitro, and that the high sensitivity of GCSs to anti-folates may be due to the increased expression of RFC-1/SLC19A1, the reduced folate carrier that transports MTX into cells, in GSCs. Of note, in an in vivo serial transplantation model, MTX alone failed to exhibit anti-GSC effects but promoted the anti-GSC effects of CEP1347, an inducer of GSC differentiation. This suggests that folate metabolism, which plays an essential role specifically in GSCs, is a promising target of anti-GSC therapy, and that the combination of cytotoxic and differentiation therapies may be a novel and promising approach to effectively eliminate cancer stem cells.

Targeting folate receptor beta on monocytes/macrophages renders rapid inflammation resolution independent of root causes

SummaryProvoked by sterile/nonsterile insults, prolonged monocyte mobilization and uncontrolled monocyte/macrophage activation can pose imminent or impending harm to the affected organs. Curiously, folate receptor beta (FRβ), with subnanomolar affinity for the vitamin folic acid (FA), is upregulated during immune activation in hematopoietic cells of the myeloid lineage. This phenomenon has inspired a strong interest in exploring FRβ-directed diagnostics/therapeutics. Previously, we have reported that FA-targeted aminopterin (AMT) therapy can modulate macrophage function and effectively treat animal models of inflammation. Our current investigation of a lead compound (EC2319) leads to discovery of a highly FR-specific mechanism of action independent of the root causes against inflammatory monocytes. We further show that EC2319 suppresses interleukin-6/interleukin-1β release by FRβ+ monocytes in a triple co-culture leukemic model of cytokine release syndrome with anti-CD19 chimeric antigen receptor T cells. Because of its chemical stability and metabolically activated linker, EC2319 demonstrates favorable pharmacokinetic characteristics and cross-species translatability to support future pre-clinical and clinical development.

Co-Delivery of Doxorubicin and Chloroquine by Polyglycerol Functionalized MoS2 Nanosheets for Efficient Multidrug-Resistant Cancer Therapy.

2D MoS2 has shown a great potential in biomedical applications, due to its superior loading capacity, photothermal property, and biodegradation. In this work, polyglycerol functionalized MoS2 nanosheets with photothermal and pH dual-stimuli responsive properties are used for the co-delivery of doxorubicin and chloroquine and treatment of multidrug-resistant HeLa (HeLa-R) cells. The polyglycerol functionalized MoS2 nanosheets with 80nm average size show a high biocompatibility and loading efficiency (≈90%) for both drugs. The release of drugs from the nanosheets at pH 5.5 is significantly promoted by laser irradiation leading to efficient destruction of incubated HeLa-R cells. In vitro evaluation shows that the designed nanoplatform has a high ability to kill HeLa-R cells. Confocal experiments demonstrate that the synthesized drug delivery system enhances the cellular uptake of DOX via folic acid targeting ligand. Taking advantage of the combined properties including biocompatibility and targeting ability as well as high loading capacity and photothermal release, this multifunctional nanosystem is a promising candidate for anticancer therapy.

Immunogenic camptothesome nanovesicles comprising sphingomyelin-derived camptothecin bilayers for safe and synergistic cancer immunochemotherapy.

Despite the enormous therapeutic potential of immune checkpoint blockade (ICB), it benefits only a small subset of patients. Some chemotherapeutics can switch 'immune-cold' tumours to 'immune-hot' to synergize with ICB. However, safe and universal therapeutic platforms implementing such immune effects remain scarce. We demonstrate that sphingomyelin-derived camptothecin nanovesicles (camptothesomes) elicit potent granzyme-B- and perforin-mediated cytotoxic T lymphocyte (CTL) responses, potentiating PD-L1/PD-1 co-blockade to eradicate subcutaneous MC38 adenocarcinoma with developed memory immunity. In addition, camptothesomes improve the pharmacokinetics and lactone stability of camptothecin, avoid systemic toxicities, penetrate deeply into the tumour and outperform the antitumour efficacy of Onivyde. Camptothesome co-load the indoleamine 2,3-dioxygenase inhibitor indoximod into its interior using the lipid-bilayer-crossing capability of the immunogenic cell death inducer doxorubicin, eliminating clinically relevant advanced orthotopic CT26-Luc tumours and late-stage B16-F10-Luc2 melanoma, and achieving complete metastasis remission when combined with ICB and folate targeting. The sphingomyelin-derived nanotherapeutic platform and doxorubicin-enabled transmembrane transporting technology are generalizable to various therapeutics, paving the way for transformation of the cancer immunochemotherapy paradigm.

A folate-targeted PEGylated cyclodextrin-based nanoformulation achieves co-delivery of docetaxel and siRNA for colorectal cancer

Docetaxel (DTX) is a chemotherapeutic agent used for a range of cancers, but it has little activity against colorectal cancer (CRC). However, combination therapy with other therapeutic agents is a potential strategy to enhance the efficacy of DTX in CRC treatment. The nuclear factor-κB (NF-κB) signaling pathway is implicated in a variety of malignancies (e.g., CRC), and the blockade of NF-κB may increase the sensitivity of cancer cells to chemotherapy. The application of small interference RNA (siRNA) to inhibit the translation of complementary mRNA has demonstrated the potential for cancer gene therapy. In this study, an amphiphilic cationic cyclodextrin (CD) nanoparticle modified with PEGylated folate (FA; a ligand to target folate receptor on CRC) has been developed for co-delivery of DTX and siRNA (against the RelA, a subunit of NF-κB) in the treatment of CRC. The resultant co-formulation (CD.DTX.siRelA.PEG-FA) achieved cell-specific uptake indicating the function of the folate targeting ligand. The CD.DTX.siRelA.PEG-FA nanoparticle enhanced the apoptotic effect of DTX with the downregulation of RelA expression, which significantly retarded the growth of CRC in mice, without causing significant toxicity. These results suggest that the FA-targeted PEGylated CD-based co-formulation provides a promising strategy for combining DTX and siRNA in treating CRC.

Folic Acid-Targeted Paclitaxel-Polymer Conjugates Exert Selective Cytotoxicity and Modulate Invasiveness of Colon Cancer Cells.

Although selective tumor delivery of anticancer drugs has been sought by exploiting either passive targeting or by ligand-mediated targeting, a selective anticancer therapy remains an unmet medical need. Despite the advances which have been achieved by nanomedicines, nanosystems such as polymer-drug conjugates still miss the goal of clinical efficacy. In this study, we demonstrated that polymer-drug conjugates require a thoroughly chemical design and the right targeting agent/polymer ratio to be selective and effective towards cancer cells. In particular, two PEG conjugates carrying paclitaxel and targeted with different folic acid (FA)/PEG ratios (one or three) were investigated. The cytotoxicity study in positive (HT-29) and negative (HCT-15) FA receptor (FR)-cell lines demonstrated that the conjugates with one or three FAs were 4- or 28-fold more active in HT-29 cells, respectively. The higher activity of the 3-FA conjugate was confirmed by its strong impact on cell cycle arrest. Furthermore, FA targeting had a clear effect on migration and invasiveness of HT-29 cells, which were significantly reduced by both conjugates. Interestingly, the 3-FA conjugate showed also an improved pharmacokinetic profile in mice. The results of this study indicate that thorough investigations are needed to optimize and tune drug delivery and achieve the desired selectivity and activity towards cancer cells.

Acid-activated ROS generator with folic acid targeting for bacterial biofilm elimination

Many medical and chemical applications require the precise supply of antimicrobial components in a controlled manner at the location of mature biofilm deposits. This work reports a facile strategy to fabricate nanoscale metal-organic frameworks (NMOFs) coencapsulating the antibacterial ligand (lysine carbon dots, Lys-CDs) and targeted drug (folic acid, FA) in one pot to improve antibiofilm efficiency against established biofilms. The resulting products are characterized by transmission electron microscopy, field-emission scanning electron microscopy, powder x-ray diffraction, and ultraviolet-visible spectroscopy. The results show that Lys-CDs could coordinate with Zn2+ and the adding of FA inhibits the coordination of Lys-CDs with central ions of Zn. The Lys-CDs and FA are successfully exposed with the NMOFs disintegrating in the acid environment of bacterial metabolites. We are surprised to find a sharp increase of reactive oxygen species (ROS) inside the bacterial cells by FA functionalizing NMOFs, which undoubtedly enhance the antibacterial and antibiofilm activity. The as-synthesized ZIF-8-based nanocomposites also show the peroxidase-like activity in an acid environment, and produce extremely active hydroxyl radicals resulting in the improved antibacterial and antibiofilm activity. The possible mechanisms of antibacterial activities indicate that the presence of FA is significant in the sense of targeting bacteria. This study shows a novel approach to construct acid stimulation supply system which may be helpful for the research of antibiofilms.

Phase Ia study of CBP-1008, a bi-specific ligand drug conjugate targeting FRα and TRPV6, in patients with advanced solid tumors.

3077 Background: CBP-1008 is a first-in-class bi-specific ligand drug conjugate targeting folate receptor α (FRα) and vanilloid subfamily member 6 of transient receptor potential channels (TRPV6) with a high potency tublin inhibitor payload, monomethyl auristatin E (MMAE). A first-in-human, multicenter, phase I study of CBP-1008 (NCT 04740398) is ongoing, and we herein report the preliminary result of part A which is to evaluate the safety, tolerability, pharmacokinetics, and antitumor activity of CBP-1008 in solid tumors. Methods: Dose escalation commenced in single-patient cohorts for the first 2 planned dose levels and then followed by a standard 3 + 3 scheme. CBP-1008 was administered as intravenous infusion at escalating doses (0.015, 0.03, 0.12, 0.15, and 0.18 mg/kg). The primary endpoints were to determine the safety and maximum tolerated dose (MTD). Adverse events (AEs) and dose-limiting toxicities (DLTs) were evaluated. Results: Eighteen patients with advanced solid tumors who had failed multiple systemic treatment regimens were enrolled. The diseases include colorectal cancer (n = 7), breast cancer (n = 5), non-small cell lung cancer (n = 2), ovarian cancer (n = 2), adrenocortical carcinoma (n = 1), and follicular dendritic cell sarcoma (n = 1). The DLTs observed included grade 4 hypophosphatemia (0.15 mg/kg), grade 4 neutropenia (0.12, 0.15, and 0.18 mg/kg), grade 4 febrile neutropenia (FN) (0.18 mg/kg), grade 3 hyperglycemia (0.15 mg/kg), and grade 3 alanine aminotransferase (ALT) elevation (0.18 mg/kg). The most common all grade AEs suspected to be drug-related were fever (83.3%, totally limited to grade 1-2), aspartate aminotransferase (AST) elevation (72.2%, 5.6% evaluated as grade 3-4), leukopenia (66.7%, 27.8% as grade 3-4), neutropenia (66.7%, 38.9% as grade 3-4) and hypohemoglobinemia (55.6%, 5.6% as grade 3-4), with no drug-related deaths. MTD is estimated between 0.15 mg/kg and 0.18 mg/kg Q2W. Best overall response was partial response (PR) in 1 patient at 0.18 mg/kg and 4 patients (22.2%) achieved stable disease (SD). Responses occurred in patients with FRα and/or TRPV6 -positive expression advanced solid tumors. Conclusions: CBP-1008 has demonstrated acceptable safety profile. Tumor response correlating with dosing and FRα/TRPV6 receptor expression levels has been well observed. Clinical trial information: 04740398.

Magneto-Plasmonic Nanoparticle Grid Biosensor with Enhanced Raman Scattering and Electrochemical Transduction for the Development of Nanocarriers for Targeted Delivery of Protected Anticancer Drugs.

Safe administration of highly cytotoxic chemotherapeutic drugs is a challenging problem in cancer treatment due to the adverse side effects and collateral damage to non-tumorigenic cells. To mitigate these problems, promising new approaches, based on the paradigm of controlled targeted drug delivery (TDD), and utilizing drug nanocarriers with biorecognition ability to selectively target neoplastic cells, are being considered in cancer therapy. Herein, we report on the design and testing of a nanoparticle-grid based biosensing platform to aid in the development of new targeted drug nanocarriers. The proposed sensor grid consists of superparamagnetic gold-coated core–shell Fe2Ni@Au nanoparticles, further functionalized with folic acid targeting ligand, model thiolated chemotherapeutic drug doxorubicin (DOX), and a biocompatibility agent, 3,6-dioxa-octanethiol (DOOT). The employed dual transduction method based on electrochemical and enhanced Raman scattering detection has enabled efficient monitoring of the drug loading onto the nanocarriers, attaching to the sensor surface, as well as the drug release under simulated intracellular conditions. The grid’s nanoparticles serve here as the model nanocarriers for new TDD systems under design and optimization. The superparamagnetic properties of the Fe2Ni@Au NPs aid in nanoparticles’ handling and constructing a dense sensor grid with high plasmonic enhancement of the Raman signals due to the minimal interparticle distance.

Genetic polymorphism in ATIC is associated with effectiveness and toxicity of pemetrexed in non-small-cell lung cancer

Patients with advanced non-small-cell lung cancer who are treated with pemetrexed display a wide variation in clinical response and toxicity. In this prospective, multicentre cohort study, we investigated the association...

Optimization, Characterization and in vivo Evaluation of Paclitaxel-Loaded Folate-Conjugated Superparamagnetic Iron Oxide Nanoparticles

BackgroundPaclitaxel (PTX) has interesting anticancer activity. However, it is insoluble in water, which seriously hinders its use in clinical. Superparamagnetic iron oxide nanoparticles (SPIONs) are used as an ideal drug delivery system. Therefore, we proposed a folic acid (FA) targeting drug-loaded SPIONs to reduce its adverse reaction.MethodsTo improve the hydrophilicity of PTX, the structure of PTX was modified by succinic anhydride to obtain 2ʹ-succinate paclitaxel (SPTX). FA conjugated Polyethylene glycol (PEG)/polyethyleneimine (PEI)-SPIONs SPTX-loaded nanoparticles (SPTX@FA@PEG/PEI-SPIONs) were prepared by solvent volatilization and hydrogen bond adsorption, and the nano-formulation was optimized by response surface methodology (RSM). The characteristics, antitumor effect in vitro, pharmacokinetics, and biodistribution of SPTX@FA@PEG/PEI-SPIONs were evaluated.ResultsSPTX was successfully loaded on the surface of FA@PEG/PEI-SPIONs. The formation of SPTX@FA@PEG/PEI-SPIONs was exhibited water-dispersive monodispersity with high stability by RSM, and dynamic light scattering (DLS) was 178.1±3.12 nm, particle size observed in the transmission electron microscope (TEM) was 13.01±1.10 nm, and the encapsulation efficiency (EE) and loading efficiency (LE) were 81.1±1.66% and 14.8±1.46%, respectively. It enhanced the stability in normal physiological condition, accelerated drug release at tumorous pH, and preferentially prolonged the circulation time. In vitro, the SPTX@FA@PEG/PEI-SPIONs significantly targeted to folate receptor (FR) positive cancers cell (HNE-1) via the receptor-ligand mediated pathway, resulting in effective cytotoxic activity. Pharmacokinetic results demonstrated that SPTX@FA@PEG/PEI-SPIONs (t1/2=3.41 h) had longer than free SPTX or PTX (t1/2=1.67 h) in rats in vivo. Tissue distribution studies showed that SPTX@FA@PEG/PEI-SPIONs were present at high levels in the liver and help in targeting the folate receptors present on the kidneys.ConclusionThese results suggest that SPTX@FA@PEG/PEI-SPIONs offer a highly promising approach to control drug release, improve drug pharmacokinetics and actively target the nasopharyngeal carcinoma.

Polyamidoamine Dendrimers Decorated Multifunctional Polydopamine Nanoparticles for Targeted Chemo- and Photothermal Therapy of Liver Cancer Model.

The development of multifunctional drug delivery systems combining two or more nanoparticle-mediated therapies for efficient cancer treatment is highly desired. To face this challenge, a photothermally active polydopamine (PDA) nanoparticle-based platform was designed for the loading of chemotherapeutic drug and targeting of cancer cells. PDA spheres were first functionalized with polyamidoamine (PAMAM) dendrimers followed by the conjugation with polyethylene glycol (PEG) moieties and folic acid (FA) targeting ligand. The anticancer drug doxorubicin (DOX) was then absorbed on the particle surface. We performed the physico-chemical characterization of this versatile material and we assessed further its possible application in chemo- and photothermal therapy using liver cancer cell model. These nanoparticles exhibited high near-infrared photothermal conversion efficacy and allowed for loading of the drug, which upon release in specifically targeted cancer cells suppressed their growth. Using cell proliferation, membrane damage, apoptosis, and oxidative stress assays we demonstrated high performance of this nanosystem in cancer cell death induction, providing a novel promising approach for cancer therapy.

A multifunctional nanoplatform based on graphitic carbon nitride quantum dots for imaging-guided and tumor-targeted chemo-photodynamic combination therapy

Graphitic carbon nitride quantum dots (g-CNQDs) have shown great potential in imaging, drug delivery and photodynamic therapy (PDT). However, relevant research on g-CNQDs for PDT or drug delivery has been conducted separately. Herein, we develop a g-CNQDs-based nanoplatform (g-CPFD) to achieve simultaneously imaging and chemo-photodynamic combination therapy in one system. A g-CNQDs-based nanocarrier (g-CPF) is first prepared by successively introducing carboxyamino-terminated oligomeric polyethylene glycol and folic acid onto the surface of g-CNQDs via two-step amidation. The resultant g-CPF possesses good physiological stability, strong blue fluorescence, desirable biocompatibility, and visible light-stimulated reactive oxygen species generating ability. Further non-covalently loaded doxorubicin enables the system with chemotherapy function. Compared with free doxorubicin, g-CPFD expresses more efficient chemotherapy to HeLa cells due to improved folate receptor-mediated cellular uptake and intracellular pH-triggered drug release. Furthermore, g-CPFD under visible light irradiation shows enhanced inhibition on the growth of cancer cells compared to sole chemotherapy or PDT. Thus, g-CPFD exhibits exceptional anti-tumor efficiency due to folate receptor-mediated targeting ability, intracellular pH-triggered drug release and a combined treatment effect arising from PDT and chemotherapy. Moreover, this nanoplatform benefits imaging-guided drug delivery because of inherent fluorescent properties of doxorubicin and g-CPF, hence achieving the goal of imaging-guided chemo-photodynamic combination treatments.

NIR Photoregulated Theranostic System Based on Hexagonal-Phase Upconverting Nanoparticles for Tumor-Targeted Photodynamic Therapy and Fluorescence Imaging.

Although photodynamic therapy (PDT) is an effective, minimally invasive therapeutic modality with advantages in highly localized and specific tumor treatments, large and deep-seated cancers within the body cannot be successfully treated due to low transparency to visible light. To improve the therapeutic efficiency of tumor treatment in deep tissue and reduce the side effects in normal tissue, this study developed a near-infrared (NIR)-triggered upconversion nanoparticle (UCNP)-based photosensitizer (PS) carrier as a new theranostics system. The NaYF4:Yb/Er UCNPs were synthesized by a hydrothermal method, producing nanoparticles of a uniformly small size (≈20 nm) and crystalline morphology of the hexagonal phase. These UCNPs were modified with folic acid-conjugated biocompatible block copolymers through a bidentate dihydrolipoic acid linker. The polymer modified hexagonal phase UCNPs (FA-PEAH-UCNPs) showed an improved dispersibility in the aqueous solution and strong NIR-to-vis upconversion fluorescence. The hydrophobic PS, pheophorbide a (Pha), was then conjugated to the stable vectors. Moreover, these UCNP-based Pha carriers containing tumor targeting folic acid ligands exhibited the significantly enhanced cellular uptake efficiency as well as PDT treatment efficiency. These results suggested that this system could extend the excitation wavelength of PDT to the NIR region and effectively improve therapeutic efficiency of PSs.

Folic acid decorated mesoporous silica nanospheres loaded with gadolinium for breast cancer cell imaging

In cancer cells, some of the transporters are overexpressed. Therefore targeted contrast agent delivery by functionalized nanoparticles is probable to advanced molecular imaging and cancer cell identification in the early stages of cancer. In this research, folic acid-modified mesoporous silica nanospheres, loaded with gadolinium, were prepared and characterized by various techniques. FSG nanoprobe cellular uptake was analyzed quantitatively and qualitatively by ICP-AES, flow cytometry, and fluorescent microscopy in cell lines which expressed different levels of folic acid receptors. The cellular uptake of FSG nanoprobe by cancer cells was about 62% which is 2.6 times higher than cellular uptake of nanoprobe without folic acid targeting group. The average of FSG nanoprobe cellular uptake was 0.6 ± 0.1 pg Gd3+ per cancer cell without any toxicity. The r 1 relaxivity of this nanoprobe in cancer cells was measured at 10.1 ± 6.0 mM−1 s−1 per Gd3+ base. The results demonstrated that the present synthesized nanoprobe is promising one for cancer cell detection and delivering a sufficient amount of Gd3+ as contrast agents into cancer cells.

Screening of Polymer-Based Drug Delivery Vehicles Targeting Folate Receptors in Triple-Negative Breast Cancer

PurposeTo compare cellular uptake and cytotoxicity of fluorescein (FL)-labeled polyethylene glycols (PEGs) carrying 2 folate groups (targeted delivery vehicles [TDVs]) to non-PEGylated molecules with 1 or 2 folate groups. Materials and MethodsThree PEGylated TDVs and 2 non-PEGylated folic acid (FA)–fluorescein (FL) conjugates (FA-FL and FA-FL-FA) were synthesized. Two triple-negative breast cancer cell lines (MDA-MB-231and MDA-MB-468) were cultured to 70% confluency and incubated for 2 h in a folate-depleted medium. Folate receptor (FR) expression was confirmed by immunocytochemistry. Cellular uptake and cytotoxicity of compounds were measured by flow cytometry. Intracellular localization was confirmed using confocal microscopy. ResultsMDA-MB-231 demonstrated 40% more FR staining than MD-MB-468. Intracellular localization of the 2 non-PEGylated molecules (FA-FL and FA-FL-FA) and the 3 PEGylated TDVs was confirmed with confocal microscopy. Cellular uptake was independent of concentration for FA-FL, but there was 26.8% more cytotoxicity at 30 μg/mL compared with no treatment (P ≤ .05). Uptake was > 90% for FA-FL-FA at 10 μg/mL and 30 μg/mL without significant cytotoxicity (P ≤ .005). Cellular uptake was > 80% for all TDVs. The molecule containing monodispersed PEG with Mn = 1,000 g/mol had the highest uptake in both cell lines without cytotoxicity. Maximum toxicity was demonstrated by the molecule containing PEG2,000 only at the highest dose of 30 μg/mL (8.66% ± 3.94% cytotoxicity; cut-off was 20%). ConclusionsThe molecule containing monodispersed PEG with Mn = 1,000 g/mol and 2 FA targeting groups demonstrated better targetability and cellular uptake as a TDV.

Construction and Evaluation of Folic Acid-Modified 3-Bromopyruvate Cubosomes.

BackgroundDirect 3-bromopyruvate chemotherapy often causes side effects. We thus aimed to construct and evaluate folic acid-modified 3-bromopyruvate liquid crystalline nanoparticles (3BP-LCNP-FA) and assess their targeted antitumor effects in tumor-bearing nude mice.Material/MethodsA liquid crystalline nanoparticle formulation was screened, and the structure was characterized using polarizing light- and transmission electron microscopy. The folate target was then synthesized and characterized using differential scanning calorimetry and proton nuclear magnetic resonance spectroscopy. In vitro, human CNE-2Z and MDA-MB-231 tumor cells were used to evaluate 3BP-LCNP-FA effects on tumor cell morphology and proliferation. Different drug formulations were administered to tumor-bearing nude mice to observe the treatment effects. Hepatic and renal toxicities were assessed using hematoxylin and eosin-stained liver, kidney, and lung sections along with serological analysis of liver and kidney injury markers (e.g., aspartate aminotransferase, alanine transaminase, blood urea nitrogen, and creatinine). Tumor tissue was observed for changes using proliferating cell nuclear antigen immunohistochemistry and terminal deoxynucleotidyl transferase dUTP nick end labeling assay.ResultsWe successfully prepared 3BP-LCNP-FA of spherical shape with uniform size using the aforementioned techniques; drug loading did not alter crystal morphology. These cubosomes exhibited more potent antitumor activity than 3-bromopyruvate alone or non-folic acid-conjugated 3-bromopyruvate liquid crystalline nanoparticles in vitro and in vivo without obvious toxic side effects.ConclusionsIt is possible to successfully construct 3BP-LCNP-FA as a drug delivery vehicle that is more efficacious than 3-bromopyruvate and has no obvious toxic effects. Thus, folic acid-modified cubosomes can be used as effective carriers for targeted drug administration.

Abstract 2890: IMGN151 - A next generation folate receptor alpha targeting antibody drug conjugate active against tumors with low, medium and high receptor expression

Abstract Folate Receptor alpha (FRα) is an attractive antibody drug conjugate (ADC) target due to its over expression in multiple epithelial malignancies including ovarian, endometrial, triple negative breast, and non-small cell lung cancer, with limited expression on normal tissues. IMGN853 (i.e., mirvetuximab soravtansine and M9346A-sulfo-SPDB-DM4), a FRα targeting ADC, is currently in phase III (MIRASOL) clinical evaluation as monotherapy in patients with platinum-resistant epithelial ovarian cancer with high levels of FRα expression. The MIRASOL study builds on the results from the prior randomized study, FORWARD I, which demonstrated that improved outcomes with IMGN853 correlated with FRα expression, with the strongest treatment effects for all efficacy endpoints in ovarian cancer patients with FRα-high disease (Moore, ESMO 2019). In order to address the unmet needs of additional patient populations, we sought to develop a next generation FRα-targeting ADC active against tumors with a broad range of FRα expression. Development of a new molecular entity with the desired antitumor properties included optimization of the antibody format and the linker-payload. The resulting lead ADC denoted IMGN151 comprises an asymmetric, bivalent, biparatopic antibody targeting two independent epitopes of FRα, linked to the highly potent maytansinoid derivative DM21 via a stable cleavable peptide linker. The average drug per antibody ratio is 3.5. The binding, internalization and processing of the biparatopic IMGN151 and the parent monospecific antibodies were compared using 3H-antibodies. In tumor cells with medium (JHOS4) and high (KB) FRα expression the biparatopic antibody boosted antibody binding events and processing by 100% and 170%, respectively. The plasma stability of IMGN151 was tested in a cynomolgus monkey pharmacokinetic study. The stable linker increased ADC half-life by 60 hours and conjugate exposure in vivo by 40%, as compared to IMGN853. IMGN151 activity was characterized against cell lines and xenograft models with a wide range of FRα expression and compared to IMGN853. In in vitro studies, both ADCs had similar activity against FRα-high KB cells; IMGN151 was up to 200 times more active against four FRα-medium cell lines. IMGN151 had also notably stronger bystander killing activity in a mixed culture of target-positive and negative cells. In vivo IMGN151 induced complete tumor regressions of human tumor xenograft models with high (KB, H-score of 300), medium (Igrov-1 and Ishikawa, H-score of 140 and 100, respectively) and low (Ov-90, H-score of 30) FRα expression. All tested doses were well tolerated with no body weight loss observed. With a novel biparatopic antibody and linker payload design, IMGN151 has shown potent antitumor activity against ovarian cancer models with a broad range of FRα expression, which warrants further development into the clinic for patients with tumors expressing FRα at a wide range of levels. Citation Format: Olga Ab, Laura M. Bartle, Leanne Lanieri, Jose F. Ponte, Qifeng Qiu, Surina Sikka, Juliet A. Costoplus, Wayne Deats, Nicholas C. Yoder, Wayne C. Widdison, Katherine Mucciarone, Kate Selvitelli, Ying Chen, Neeraj Kohli, Thomas Chittenden, Richard Gregory, Yulius Setiady, Eric H. Westin. IMGN151 - A next generation folate receptor alpha targeting antibody drug conjugate active against tumors with low, medium and high receptor expression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2890.

Targeting folate receptors (α1) to internalize the bleomycin loaded DNA-nanotubes into prostate cancer xenograft CWR22R cells

DNA-nanotechnology based on DNA scaffolding technique is an established approach to formulate water-miscible nano-structural frameworks. We have designed the hydrophilic DNA-nanotubes (D-NTs) as a (water-soluble) vehicle to encapsulate a water-insoluble DNA-intercalating anticancer drug. Bleomycin (BM) is a model hydrophobic anticancer drug used in this study capable to bind with the D-NTs to formulate BM loaded D-NTs. This BM@D-NTs system was evaluated for the improvement of the in vitro anti-cancer effects on the resistant prostate cancer xenograft CWR22R cells, over-expressed with the folate receptors/alpha (FRα). D-NTs were functionalized with the FRα-targeting antibodies to interact with the FRα (receptors) highly expressed on the resistant prostate cancer xenograft CWR22R cells. D-NTs not only increased the aqueous miscibility/dispersibility of BM but also enhanced the therapeutic efficiency as a targeted (site-specific) drug delivery system. D-NTs synthesis was achieved by sticky ends cohesions of DNA triangular tiles. DNA triangles were self-assembled from a freshly circularized short scaffold chain (84-NT) by annealing with the various staple strands. The polymerization of the triangular tiles gave rise to DNA-nanosheet lattices which underwent morphological transition guided by the twists in the DNA duplexes. This DNA double helix curvature caused self-coiling of the DNA 2D nano-sheets to condense into D-NTs morphology. Native-Page gel experiment showed decreased electrophoretic mobility down the gel confirming the successful execution of the polymerized lattices via sticky ends cohesion of the DNA-triangles. The final morphology and self-coiling of 2D DNA nano-sheets were confirmed through atomic force microscopy (AFM) showed the successful synthesis of D-NTs having diameter 3 to 5 μm and length 200 to 600 nm. BM was loaded onto D-NTs via incubation of hydro-alcoholic solution of the BM with the aqueous solution of D-NTs followed by the evaporation of alcohol and intercalation of the BM onto D-NTs. The intercalation of BM onto D-NTs was confirmed by UV-shift analysis. The targeted cytotoxicity of the BM@D-NTs for the CWR22R (resistant prostate cancer xenograft) cells was confirmed through MTT assay and the flow cytometry compared to the highly compatible empty D-NTs. Confocal microscopy revealed the time-dependent transfection of BM@D-NTs into CWR22R cells compared to the control cell line.

Water-Soluble closo-Docecaborate-Containing Pteroyl Derivatives Targeting Folate Receptor-Positive Tumors for Boron Neutron Capture Therapy.

Water-soluble pteroyl-closo-dodecaborate conjugates (PBCs 1–4), were developed as folate receptor (FRα) targeting boron carriers for boron neutron capture therapy (BNCT). PBCs 1–4 had adequately low cytotoxicity with IC50 values in the range of 1~3 mM toward selected human cancer cells, low enough to use as BNCT boron agents. PBCs 1–3 showed significant cell uptake by FRα positive cells, especially U87MG glioblastoma cells, although the accumulation of PBC 4 was low compared with PBCs 1–3 and L-4-boronophenylalanine (L-BPA). The cellular uptake of PBC 1 and PBC 3 by HeLa cells was arrested by increasing the concentration of folate in the medium, indicating that the major uptake mechanisms of PBC 1–3 are primarily through FRα receptor-mediated endocytosis.