Preclinical Antitumor Activity of a Novel Folate-Targeted Dual Drug Conjugate (original) (raw)
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A Review on the Folate-Linked Prodrugs for Cancer Chemotherapy
Annals of the Romanian Society for Cell Biology, 2021
During the last few decades, many methods have been developed in order to facilitate the drug design and discovery phases. Most of these methods were devoted to find new chemical entities that provide the most meaningful interaction with the desired receptors or enzymes with the potential to have minimal unwanted interaction. However, this strategy is time consuming, costly and requires screening of thousands of molecules for biological activity of which only one might enter the drug market. One of the most attractive and promising method is the prodrug approach, in which the active drug molecule is masked by a promoiety to alter its undesired properties.It is concluded that These FR-targeted technologies can also pave the way for inspiring further sophisticated drug conjugates, especially as this receptor is being targeted by use of several complementary technologies: small molecule, nanoparticle and protein-based thus providing broad and distinct knowledge in the area.
Cancer chemotherapy and pharmacology, 2017
EC0305 represents a folate-tubulysin B construct capable of specifically eradicating folate receptor (FR)-positive subcutaneous tumors from mice (Leamon et al., Cancer Res 68:9839-9844, 8). Herein we report on the use of multiple polar carbohydrate segments (e.g. 1-amino-1-deoxy-glucitolyl-γ-glutamate) placed in-between the folate and tubulysin B moieties of EC0305 creating a new conjugate, herein referred to as EC0531, with more desirable biological properties. The synthesis of EC0531 and its tritium-labeled counterpart are described. EC0531's affinity for FR binding and specific cytotoxic activity was assessed using standard in vitro assays. Human tumor xenografts were used to directly compare EC0305 and EC0531's antitumor activity. Finally, bile duct cannulated, female Sprague-Dawley rats were used to compare hepatobiliary clearance of these two targeted chemotherapeutic agents. EC0531 tightly binds to the FR with an affinity about half that of folic acid. It was found to...
Bioconjugate Chemistry, 2012
The development of tumor-targeting drug delivery systems, able to selectively transport cytotoxic agents into the tumor site by exploiting subtle morphological and physiological differences between healthy and malignant cells, currently stands as one of the most attractive anticancer strategies used to overcome the selectivity problems of conventional chemotherapy. Owing to frequent overexpression of folate receptors (FRs) on the surface of malignant cells, conjugation of cytotoxic agents to folic acid (FA) via suitable linkers have demonstrated to enhance selective drug delivery to the tumor site. Herein, the chemical synthesis and biological evaluation of two novel folate-conjugates bearing the anticancer agent chlorambucil (CLB) tethered to either an aminoether (4,7,10-trioxa-1,13-tridecanediamine) or a pseudo-β-dipeptide (β-Ala-ED-β-Ala) linker is reported. The two drug delivery systems have been prepared in high overall yields (54% and 34%) through straightforward and versatile synthetic routes. Evaluation of cell specificity was examined using three leukemic cell lines, undifferentiated U937 (not overexpressing FRs, FR −), TPA-differentiated U937 (overexpressing FRs, FR +), and TK6 (FR +) cells. Both conjugates exhibited high specificity only to FR + cells (particularly TK6), demonstrating comparable antitumor activity to CLB in its free form. These data confirm the reliability of folate-based drug delivery systems for targeted antitumor therapy; likewise, they lay the foundations for the development of other folate-conjugates with antitumor potential.
Characterization and Use of Folate Receptor Isoforms for Targeting of Epithelial and Myeloid Cells
2016
Under the Supervision of Professor Douglas A. Steeber Folate receptor (FR) is a GPI-anchored glycoprotein with high binding affinity for folic acid. FR has two membrane-associated isoforms, α and β, that are overexpressed on epithelial and myeloid tumors, respectively. Normal cells may also exhibit FR expression at very low levels but interestingly, FR-α on normal cells is restricted to the apical surface i.e., away from the blood stream. This differential expression and orientation of the FR-α isoform on tumor cells has been exploited to selectively target and deliver conjugates (e.g., drugs, nanoparticles, liposomes) to tumor cells without harming neighboring healthy cells. However, the functions and use of FR-β as a potential target have not been explored, and its functions on myeloid cells remain largely unknown. Therefore, we investigated the functions of FR-β to determine its potential as a target in myeloid malignancies using a human myelomonocytic leukemia cell line, U937. FR-α studies were conducted using a murine epithelial breast carcinoma cell line, 4T1, and tumors harvested from 4T1 tumor-bearing mice. The isoforms were found overexpressed on tumor cells and tissues, both in vitro and in vivo, with no expression observed on corresponding normal cells. Studies conducted using folic acid-fluorochrome conjugates to determine intracellular receptor fate indicated that FR-β was not internalized into cells unlike FR-α. However, both isoforms iii exhibited strong binding to folic acid conjugates (e.g., fluorochromes, nanoparticles) thus indicating that they could be selectively targeted using folic acid-dependent methods. We also determined the potential of a novel histone deacetylase (HDAC) inhibitor (HDACi) as an anti-cancer agent that could be used along with folic acid for achieving better selectivity in targeting tumor cells. Preliminary studies showed that Compound 5 (Cpd5) is stable with strong anti-proliferative activities against human tumor cells. Cpd5 was also able to reduce the rate of 4T1 tumor growth in mice without inducing systemic toxicity in the animals. In addition, Cpd5 exhibited desirable pharmacokinetic properties and showed direct effects on acetylation levels of histone proteins. These studies not only provide insights into the functional differences associated with FR-α and FR-β isoforms, but also highlight the potential of future targeting strategies utilizing these to target both epithelial and myeloid malignancies with improved selectivity.
Utilizing the folate receptor for active targeting of cancer nanotherapeutics
NANO REVIEWS, 2012
The development of specialized nanoparticles for use in the detection and treatment of cancer is increasing. Methods are being proposed and tested that could target treatments more directly to cancer cells, which could lead to higher efficacy and reduced toxicity, possibly even eliminating the adverse effects of damage to the immune system and the loss of quick replicating cells. In this mini-review we focus on recent studies that employ folate nanoconjugates to target the folate receptor. Folate receptors are highly overexpressed on the surface of many tumor types. This expression can be exploited to target imaging molecules and therapeutic compounds directly to cancerous tissues.
Synthesis and Biological Evaluation of EC72: A New Folate-Targeted Chemotherapeutic
Bioconjugate Chemistry, 2005
A novel folate conjugate of mitomycin C, herein referred to as EC72, was designed and evaluated for biological activity against FR-positive cells and tumors. EC72 was produced by coupling folic acid-γcysteine to 7-N-modified MMC via a disulfide bond. This water soluble conjugate was found to retain high affinity for FR-positive cells, and it produced dose responsive activity in vitro against a panel of folate receptor (FR)-positive cell lines. EC72's activity was considered to be targeted and specific for the FR since (i) excess folic acid blocked biological activity, and (ii) FR-negative cell lines were unresponsive to this drug. Initial in vivo tests confirmed EC72's activity in both syngeneic and xenograft models, and this activity occurred in the apparent absence of gross or pathological toxicity. These results are significant, since daily dosing of EC72 for more than 30 consecutive days yielded no evidence of myelosuppression or toxicity to major organs, including the FR-positive kidneys. The latter observation supports published data, indicating that the apically oriented kidney proximal tubule FRs function to salvage folates prior to their excretion and to return these molecules back into systemic circulation. Overall, EC72's performance in vitro and in vivo warrants further preclinical study before this novel targeted chemotherapeutic is considered for clinical investigation. EXPERIMENTAL PROCEDURES Materials. N 10-Trifluoroacetylpteroic acid was purchased from Eprova AG, Schaffhausen, Switzerland. Peptide synthesis reagents were purchased from Nova-Biochem (La Jolla, CA) and Bachem (San Carlos, CA). Folate-free RPMI media (FFRPMI) and PBS were obtained from Gibco, Grand Island, NY. 3 H-Thymidine and N 1a-(3 H-methyl)mitomycin K were purchased from Moravek Biochemicals, Brea, CA. Synthesis, Purification, and Analytical Characterization of EC72 and 3 H-Methyl-EC72. Construction of EC72 began with the synthesis of the thiol containing folate linker, Pte-γGlu-Cys-OH, using a preloaded Fmoc-Cys(Trt) Wang resin and standard solid-phase techniques. The linker was purified on a preparative RP-HPLC system connected to a Novapak HR C18 19 × 300
Macromolecular bioscience, 2017
The conjugation of small molecule drugs to ligand containing carrier systems facilitates receptor targeted delivery. The folate receptor (FR) constitutes an ideal target for tumor selective therapy, being overexpressed on several tumor types. It can be targeted using the vitamin folic acid (FolA) or the structurally related drug methotrexate (MTX). Several sequence-defined oligoamides with mono- and multivalent FolA or MTX ligands and an additional thiol conjugation site are synthesized via solid-phase assisted synthesis. Their structure activity relationships are assessed in respect to dihydrofolate reductase inhibition, receptor mediated endocytosis, and cytotoxicity. Then, the tubulin-binding agent pretubulysin (PT), a highly potent drug exhibiting antitumoral, antiangiogenic, and antimetastatic properties, is conjugated via an activated mercaptane derivative to the set of FR-targeting oligoamides. In a combined PT/MTX cytotoxicity study in FR-overexpressing KB and L1210 cells, a...
In-Silico Study of Novel Folate Analogues as Anticancer which Inhibits Dihydrofolate Reductase
Scientific Journal of PPI - UKM, 2016
Dihydrofolate reductase (DHFR) has an important function in folic analogues biosynthesis which is used as nutrition for cells. In a specific cancer cell, DHFR has bigger expression than normal cells therefore it is good candidates as target to cancer chemotherap. In this research the screening have been done to 10-N-(4’-bromobenzoyl) folic acid and 10-N-(p-toluoyl) folic acid by in silico method. The result of molecular docking shows that those two compounds have more stable interaction than other DHFR inhibitors (methotrexate) but those two compound do not follow the Lipinsky’s rule of 5 which is affected to its bioavailability.
Synthesis and evaluation of a 68Ga labeled folic acid derivative for targeting folate receptors
Applied Radiation and Isotopes, 2016
NOTA-Bn-(3-aminopropyl) folic acid conjugate was synthesized and characterized by 1 H-NMR, ESI-MS and HPLC analysis. NOTA-folic acid conjugate radiolabeled with 68 Ga in 495% yields and high serum stability (Z95%) upto 1 h. In vitro studies in KB cells showed specificity of NOTA-Bn-(3-aminopropyl) folic acid. A maximum cell uptake of 1.770.4% per million KB cells was observed for 68 Ga-NOTA-folic acid.