ABSTRACT
The AAA+ ATPase p97 (valosin-containing protein, VCP) is a master regulator of protein homeostasis and therefore represents a novel target for cancer therapy. Starting from a known allosteric inhibitor, NMS-873, we systematically optimized this scaffold, in particular, by applying a benzene-to-acetylene isosteric replacement strategy, specific incorporation of F, and eutomer/distomer identification, which led to compounds that exhibited nanomolar biochemical and cell-based potency. In cellular pharmacodynamic assays, robust effects on biomarkers of p97 inhibition and apoptosis, including increased levels of ubiquitinated proteins, CHOP and cleaved caspase 3, were observed. Compound (R)-29 (UPCDC-30766) represents the most potent allosteric inhibitor of p97 reported to date.
ABSTRACT
Cisplatin is a platinum-based chemotherapeutic agent widely used in the treatment of various solid tumors. However, a major challenge in the use of cisplatin and in the development of cisplatin derivatives, namely Pt(iv) prodrugs, is their premature reduction in the bloodstream before reaching cancer cells. To circumvent this problem, we designed liposomal nanoparticles coupled with a cholesterol-tethered amphiphilic Pt(iv) prodrug. The addition of cholesterol served to stabilize the formation of the liposome, while selectively incorporating cholesterol as the axial ligand also allowed the Pt(iv) prodrug to readily migrate into the liposomal bilayer. Notably, upon embedding into the nanoparticles, the Pt(iv) prodrug showed marked resistance against premature reduction in human plasma in vitro. Pharmacokinetic analysis in a mouse model also showed that the nanoparticles significantly extend the half-life of the Pt(iv) prodrug to 180 min, which represents a >6-fold increase compared to cisplatin. Importantly, such lipid modification did not compromise the genotoxicity of cisplatin, as the Pt(iv) prodrug induced DNA damage and apoptosis in ovarian cancer cell lines efficiently. Taken together, our strategy provides a novel insight as to how to stabilize a platinum-based compound to increase the circulation time in vivo, which is expected to enhance the efficacy of drug treatment.
Subject(s)
Antineoplastic Agents/pharmacology , Nanoparticles/chemistry , Organoplatinum Compounds/pharmacology , Prodrugs/pharmacology , Surface-Active Agents/pharmacology , Antineoplastic Agents/blood , Antineoplastic Agents/chemistry , Apoptosis/drug effects , Cell Proliferation/drug effects , Cholesterol/blood , Cholesterol/chemistry , Cholesterol/pharmacology , Cisplatin/blood , Cisplatin/chemistry , Cisplatin/pharmacology , DNA Damage , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Humans , Liposomes/blood , Liposomes/chemistry , Molecular Structure , Nanoparticles/metabolism , Organoplatinum Compounds/blood , Organoplatinum Compounds/chemistry , Prodrugs/chemistry , Prodrugs/metabolism , Structure-Activity Relationship , Surface-Active Agents/chemistry , Surface-Active Agents/metabolism , Time Factors , Tumor Cells, CulturedABSTRACT
We developed a spermine-conjugated lipophilic Pt(iv) prodrug that is able to reduce the cancer stem cell population in ovarian cancer. The therapeutic effect is attributed to the hydrophobic tail and cationic spermine head group, the combination of which allows the Pt(iv) prodrug to localize in mitochondria and induce corresponding damage.
Subject(s)
Antineoplastic Agents/pharmacology , Neoplastic Stem Cells/drug effects , Ovarian Neoplasms/pathology , Platinum Compounds/pharmacology , Prodrugs/pharmacology , Spermine/chemistry , Cell Line, Tumor , Female , Flow Cytometry , Humans , Hydrophobic and Hydrophilic Interactions , Prodrugs/chemistry , Spectrophotometry, Atomic , Spermine/pharmacologyABSTRACT
To modulate biological functions, G-quadruplexes in genome are often non-specifically targeted by small molecules. Here, specificity is increased by targeting both G-quadruplex and its flanking duplex DNA in a naturally occurring dsDNA-ssDNA telomere interface using polyamide (PA) and pyridostatin (PDS) conjugates (PA-PDS). We innovated a single-molecule assay in which dissociation constant (Kd) of the conjugate can be separately evaluated from the binding of either PA or PDS. We found Kd of 0.8 nM for PA-PDS, which is much lower than PDS (Kd â¼ 450 nM) or PA (Kd â¼ 35 nM). Functional assays further indicated that the PA-PDS conjugate stopped the replication of a DNA polymerase more efficiently than PA or PDS. Our results not only established a new method to dissect multivalent binding into actions of individual monovalent components, they also demonstrated a strong and specific G-quadruplex targeting strategy by conjugating highly specific duplex-binding molecules with potent quadruplex ligands.
Subject(s)
Aminoquinolines/chemistry , Nylons/chemistry , Picolinic Acids/chemistry , Telomere/chemistry , Base Sequence , DNA/chemical synthesis , DNA/chemistry , DNA/metabolism , Humans , Substrate Specificity , Telomere/metabolismABSTRACT
A long-standing challenge in the treatment of ovarian cancer is drug resistance to standard platinum-based chemotherapy. Recently, increasing attention has been drawn to the use of self-assembled metal-organic complexes as novel therapeutics for cancer treatment. However, high hydrophobicity that is often associated with these structures lowers their solubility and hinders their clinical translation. In this article, we present a proof-of-concept study of using nanoprecipitation to formulate the hydrophobic metal-organic cages and facilitate their use in treating chemoresistant ovarian cancer. The Pt6L4 Cage 1 is an octahedral cage formed by self-assembly of six 1,10-phenanthroline-Pt(II) centers and four 2,4,6-tris(4-pyridyl)-1,3,5-triazine ligands (L). Cage 1 is able to trigger DNA damage and exhibits promising in vitro potency against a panel of human ovarian cancer cell lines. However, due to the large portion of aromatic components, this cage structure has very limited solubility in cell culture media (<20µM). Notably, upon nanoformulation by using fluorescein (2) and a pegylated anionic polymer (3), the concentration of Cage 1 can reach up to 0.4 mM. Production of the nanoparticles of metal-organic cages (nMOC) is driven by the formation of the 1:1 host-guest complex of 1 and 2 in aqueous solution, which then form nanoprecipitation in presence of poly glutamic acid-b-poly ethylene glycol (3). The resulted nMOC are about 100 nm in diameter, and they serve as a delivery platform that slowly releases the therapeutic content. The use of fluorescein facilitates monitoring cell entry of nMOC and drug release using flow cytometry. Finally, comparing to cisplatin, the nMOC exhibit comparable in vitro efficacy against a panel of human cancer cell lines, and notably, it shows a much lower resistance factor against chemoresistant ovarian cancer cell lines.
ABSTRACT
Optimization of the side-chain of a phenyl indole scaffold identified from a high-throughput screening campaign for inhibitors of the AAA+ ATPase p97 is reported. The addition of an N-alkyl piperazine led to high potency of this series in a biochemical assay, activity in cell-based assays, and excellent pharmaceutical properties. Molecular modeling based on a subsequently obtained cryo-EM structure of p97 in complex with a phenyl indole was used to rationalize the potency of these allosteric inhibitors.
ABSTRACT
While mu opioid receptor (MOR) agonists are especially effective as broad-spectrum pain relievers, it has been exceptionally difficult to achieve a clear separation of analgesia from many problematic side effects. Recently, many groups have sought MOR agonists that induce minimal ßarrestin-mediated signaling because MOR agonist-treated ßarrestin2 knockout mice were found to display enhanced antinociceptive effects with significantly less respiratory depression and tachyphylaxis. Substantial data now exists to support the premise that G protein signaling biased MOR agonists can be effective analgesic agents. We recently showed that, within a chemical series, the degree of bias correlates linearly with the magnitude of the respiratory safety index. Herein we describe the synthesis and optimization of piperidine benzimidazolone MOR agonists that together display a wide range of bias (G/ßarr2). We identify structural features affecting potency and maximizing bias and show that many compounds have desirable properties, such as long half-lives and high brain penetration.
Subject(s)
Analgesics, Opioid/pharmacology , Blood-Brain Barrier/metabolism , Drug Discovery/standards , GTP-Binding Proteins/metabolism , Microsomes, Liver/metabolism , Receptors, Opioid, mu/agonists , Analgesics, Opioid/chemistry , Animals , Blood-Brain Barrier/drug effects , Humans , Male , Mice , Mice, Inbred C57BL , Microsomes, Liver/drug effects , Protein Conformation , Structure-Activity Relationship , beta-Arrestins/metabolismABSTRACT
This article presents a new strategy to engage coordination-driven self-assembly for platinum drug delivery. The self-assembled supramolecular hexagon is conjugated with three equivalents of Pt(iv) prodrugs and displays a superior therapeutic index compared to cisplatin against a panel of human cancer cell lines.
Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Macromolecular Substances/chemistry , Organoplatinum Compounds/pharmacology , Prodrugs/chemistry , Prodrugs/pharmacology , Antineoplastic Agents/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Cisplatin/administration & dosage , Cisplatin/chemistry , Cisplatin/pharmacology , Dose-Response Relationship, Drug , Drug Delivery Systems , Drug Screening Assays, Antitumor , Humans , Macromolecular Substances/chemical synthesis , Macromolecular Substances/pharmacology , Models, Molecular , Molecular Structure , Organoplatinum Compounds/chemical synthesis , Organoplatinum Compounds/chemistry , Prodrugs/chemical synthesis , Structure-Activity RelationshipABSTRACT
We present a novel design to use metal-organic cages (MOCs) to encapsulate Pt-based anticancer agents for delivery. A fluorescein-conjugated Pt(iv) prodrug of cisplatin is developed for its encapsulation in a cationic MOC via host-guest interactions, which then forms drug-loaded nanoparticles with an anionic polymer.
Subject(s)
Antineoplastic Agents/chemistry , Cisplatin/chemistry , Drug Carriers/chemistry , Nanoparticles/chemistry , Organometallic Compounds/chemistry , Antineoplastic Agents/metabolism , Apoptosis/drug effects , Capsules , Cisplatin/metabolism , Cisplatin/pharmacology , HeLa Cells , Humans , Prodrugs/metabolismABSTRACT
Biased agonism has been proposed as a means to separate desirable and adverse drug responses downstream of G protein-coupled receptor (GPCR) targets. Herein, we describe structural features of a series of mu-opioid-receptor (MOR)-selective agonists that preferentially activate receptors to couple to G proteins or to recruit ßarrestin proteins. By comparing relative bias for MOR-mediated signaling in each pathway, we demonstrate a strong correlation between the respiratory suppression/antinociception therapeutic window in a series of compounds spanning a wide range of signaling bias. We find that ßarrestin-biased compounds, such as fentanyl, are more likely to induce respiratory suppression at weak analgesic doses, while G protein signaling bias broadens the therapeutic window, allowing for antinociception in the absence of respiratory suppression.
Subject(s)
Analgesics, Opioid/administration & dosage , Analgesics, Opioid/adverse effects , Receptors, Opioid, mu/agonists , Animals , Fentanyl/administration & dosage , GTP-Binding Proteins/metabolism , Mice , Morphine/administration & dosage , Receptors, Opioid, mu/chemistry , Respiratory System/drug effects , Signal Transduction , beta-Arrestins/metabolismABSTRACT
Exploratory SAR studies of a new phenyl indole chemotype for p97 inhibition revealed C-5 indole substituent effects in the ADPGlo assay that did not fully correlate with either electronic or steric factors. A focused series of methoxy-, trifluoromethoxy-, methyl-, trifluoromethyl-, pentafluorosulfanyl-, and nitro-analogues was found to exhibit IC50s from low nanomolar to double-digit micromolar. Surprisingly, we found that the trifluoromethoxy-analogue was biochemically a better match of the trifluoromethyl-substituted lead structure than a pentafluorosulfanyl-analogue. Moreover, in spite of their almost equivalent strongly electron-depleting effect on the indole core, pentafluorosulfanyl- and nitro-derivatives were found to exhibit a 430-fold difference in p97 inhibitory activities. Conversely, the electronically divergent C-5 methyl- and nitro-analogues both showed low nanomolar activities.
ABSTRACT
Two series of novel 2-substituted 5,7-dihydroxyanthra[2,1-d]thiazole-6,11-dione derivatives from natural rhein were designed, synthesized and evaluated for their antitumour activities against human cancer cell lines A549 and HeLa in vitro.
Subject(s)
Anthraquinones/chemical synthesis , Anthraquinones/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Biological Products/chemical synthesis , Biological Products/pharmacology , Drug Design , Thiazoles/chemical synthesis , Thiazoles/pharmacology , Anthraquinones/chemistry , Antineoplastic Agents/chemistry , Biological Products/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , HeLa Cells , Humans , Molecular Structure , Structure-Activity Relationship , Thiazoles/chemistryABSTRACT
A series of pyrido[3,2-α]carbazole derivatives and their analogues have been prepared and evaluated for their antitumour activity against human lung cancer A549 cells and colon cancer HT29 cells. The intermediates 4a-4k are successfully synthesized from 1a-1k and ethyl 2-(3-bromopyridin-2-yl)acetate by Knoevenagel condensation and intramolecular Heck-type reaction, and this is a novel and efficient synthetic approach to the core scaffold of the target compounds. These target compounds have shown an interesting antitumour profile towards the tested cell lines with IC50 values ranging from 0.07 µM to 4.45 µM. Among all the compounds synthesized, 8 compounds show higher potency than R16, 12 compounds are as potent as R16, and 6 compounds are less potent than R16. The best compound 24 is 7 times and approximately 10 times as potent as R16 against A549 and HT29 cells, respectively.
Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Carbazoles/chemical synthesis , Carbazoles/pharmacology , Drug Design , Pyridines/chemical synthesis , Pyridines/pharmacology , Antineoplastic Agents/chemistry , Carbazoles/chemistry , Chemistry Techniques, Synthetic , HT29 Cells , Humans , Hydrogen Bonding , Inhibitory Concentration 50 , Naphthalimides/chemistry , Pyridines/chemistry , SolubilityABSTRACT
The palladium-catalyzed cross-coupling reaction of 3-iodochromones, thiochromones, and quinolones with ethyl bromodifluoroacetate in the presence of a copper mediator is reported. Under optimized conditions, all reactions worked well and provided difluoro-containing products in moderate to excellent yields.