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ACS Omega Jul 2020The process selection and subsequent development of a reliable, scalable synthesis of the anticancer prodrug tirapazamine (SR259075) is described in this paper. Reaction...
The process selection and subsequent development of a reliable, scalable synthesis of the anticancer prodrug tirapazamine (SR259075) is described in this paper. Reaction of benzofuroxan with cyanamide in acetonitrile in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene at 20-25 °C afforded, after an acidic workup, the targeted molecule in good yield at a kilogram scale. Notable critical parameters and safety enhancements are defined and successfully implemented to produce three consecutive validation batches in a reproducible manner.
PubMed: 32685820
DOI: 10.1021/acsomega.0c01250 -
Theranostics 2020Abnormal tumor microenvironment, such as hypoxia, interstitial hypertension and low pH, leads to unexpected resistance for current tumor treatment. The development of...
Abnormal tumor microenvironment, such as hypoxia, interstitial hypertension and low pH, leads to unexpected resistance for current tumor treatment. The development of versatile drug delivery systems which present responsive characteristics to tumor microenvironment (TME) has been extensively carried out, but remains challenging. In this study, zeolitic imidazolate framework-8 (ZIF-8) coated ZnS nanoparticles have been designed and prepared for co-delivery of ICG/TPZ molecules, denoted as ZSZIT, for HS-amplified synergistic therapy. The ZSZ nanoparticles were characterized using SEM, TEM and XRD. The viabilities of cancer cells cultured with ZSZIT under normoxia/hypoxia conditions were evaluated by cell counting kit-8 (CCK-8) assay. In addition, anti-tumor effect was also performed using male Balb/c nude mice as animal model. ZSZIT shows cascade PDT and hypoxia-activated chemotherapeutic effect under an 808nm NIR irradiation. Meanwhile, ZSZIT degrades under tumor acidic environment, and HS produced by ZnS cores could inhibit the expression of catalase, which subsequently favors the hypoxia and antitumor effect of TPZ drug. Both and studies demonstrate the HS-sensitized synergistic antitumor effect based on cascade PDT/chemotherapy. This cascade HS-sensitized synergistic nanoplatform has enabled more effective and lasting anticancer treatment.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Drug Carriers; Drug Compounding; Drug Synergism; Humans; Hydrogen Sulfide; Indocyanine Green; Male; Metal Nanoparticles; Metal-Organic Frameworks; Mice; Neoplasms; Photochemotherapy; Prodrugs; Tirapazamine; Tumor Hypoxia; Tumor Microenvironment; Xenograft Model Antitumor Assays; Zeolites
PubMed: 32685012
DOI: 10.7150/thno.45079 -
Journal of Pharmacy & Pharmaceutical... 2020The reduction potentials of bioreductively-activated drugs represent an important design parameter to be accommodated in the course of creating lead compounds and...
The reduction potentials of bioreductively-activated drugs represent an important design parameter to be accommodated in the course of creating lead compounds and improving the efficacy of older generation drugs. Reduction potentials are traditionally reported as single-electron reduction potentials, E(1), measured against reference electrodes under strictly defined experimental conditions. More recently, computational chemists have described redox properties in terms of a molecule's highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), in electron volts (eV). The relative accessibility of HOMO/LUMO data through calculation using today's computer infrastructure and simplified algorithms make the calculated value (LUMO) attractive in comparison to the accepted but rigorous experimental determination of E(1). This paper describes the correlations of eV (LUMO) to E(1) for three series of bioreductively-activated benzotriazine di-N-oxides (BTDOs), ring-substituted BTDOs, ring-added BTDOs and a selection of aromatic nitro compounds. The current computational approach is a closed-shell calculation with a single optimization. Gas phase geometry optimization was followed by a single-point DFT (Density Functional Theory) energy calculation in the gas phase or in the presence of polar solvent. The resulting DFT-derived LUMO energies (eV) calculated for BTDO analogues in gas phase and in presence of polar solvent (water) exhibited very strong linear correlations with high computational efficiency (r2 = 0.9925) and a very high predictive ability (MAD = 7 mV and RMSD = 9 mV) when compared to reported experimentally determined single-electron reduction potentials.
Topics: Density Functional Theory; Electrons; Hypoxia; Oxidation-Reduction; Tirapazamine
PubMed: 32574141
DOI: 10.18433/jpps30602 -
Angewandte Chemie (International Ed. in... Sep 2020Tirapazamine (TPZ) has been tested in clinical trials on radio-chemotherapy due to its potential highly selective toxicity towards hypoxic tumor cells. It was suggested...
Tirapazamine (TPZ) has been tested in clinical trials on radio-chemotherapy due to its potential highly selective toxicity towards hypoxic tumor cells. It was suggested that either the hydroxyl radical or benzotriazinyl radical may form as bioactive radical after the initial reduction of TPZ in solution. In the present work, we studied low-energy electron attachment to TPZ in the gas phase and investigated the decomposition of the formed TPZ anion by mass spectrometry. We observed the formation of the (TPZ-OH) anion accompanied by the dissociation of the hydroxyl radical as by far the most abundant reaction pathway upon attachment of a low-energy electron. Quantum chemical calculations suggest that NH pyramidalization is the key reaction coordinate for the reaction dynamics upon electron attachment. We propose an OH roaming mechanism for other reaction channels observed, in competition with the OH dissociation.
PubMed: 32543771
DOI: 10.1002/anie.202006675 -
ACS Omega Feb 2020Triethylphosphinegold(I) complexes [Au(HL1)P(CHCH)]PF (), [Au(HL2)P(CHCH)]PF (), and [Au(HL3)P(CHCH)]PF () were obtained with...
Triethylphosphinegold(I) complexes [Au(HL1)P(CHCH)]PF (), [Au(HL2)P(CHCH)]PF (), and [Au(HL3)P(CHCH)]PF () were obtained with ()-2-(1-(2-methyl-5-nitro-1H-imidazol-1-yl)propan-2-ylidene)hydrazinecarbothioamide (), ()--methyl-2-(1-(2-methyl-5-nitro-1H-imidazol-1-yl)propan-2-ylidene)hydrazinecarbothioamide (), and ()-2-(1-(2-methyl-5-nitro-1H-imidazol-1-yl)propan-2-ylidene)--phenylhydrazinecarbothioamide (). All compounds were assayed for their cytotoxic activities against HCT-116 colorectal carcinoma cells under normoxia and hypoxia conditions and against nonmalignant HEK-293 human embryonic kidney cells under normoxia conditions. The thiosemicarbazone ligands - were inactive against HCT-116 cells under hypoxia but while was inactive, and proved to be cytotoxic to both cell lineages under normoxia conditions. Complexes (-) and the triethylphosphinegod(I) precursor proved to be active against both cell lineages in normoxia as well as in hypoxia. While and revealed to be active against HEK-293 and HCT-116 cells, being approximately as active against HCT-116 cells in normoxia as under hypoxia, complex () proved to be more active against HCT-116 cells under hypoxia than under normoxia conditions, and more active against HCT-116 cells than against the nonmalignant HEK-293 cells, with the selectivity index, calculated as SI = IC/IC, equal to 3.7, similar to the value obtained for the control drug tirapazamine (tirapazamine (TPZ), SI = 4). Although the compounds showed distinct cytotoxic activities, the electrochemical behaviors of - were very similar, as were the behaviors of complexes (-). Complex () deserves special interest since it was significantly more active under hypoxia than under normoxia conditions. Hence, in this case, selective reduction of the nitro group in a low oxygen pressure environment, resulting in toxic reactive oxygen species (ROS) and damage to DNA or other biomolecules, might operate, while for the remaining compounds, other modes of action probably occur.
PubMed: 32095716
DOI: 10.1021/acsomega.9b03778 -
Biomicrofluidics Sep 2019In anticancer drug development, it is important to simultaneously evaluate both the effect of drugs on cell proliferation and their ability to penetrate tissues. To...
In anticancer drug development, it is important to simultaneously evaluate both the effect of drugs on cell proliferation and their ability to penetrate tissues. To realize such an evaluation process, here, we present a compartmentalized tumor spheroid culture system utilizing a thin membrane with a through-hole to conduct localized anticancer treatment of tumor spheroids and monitor spheroid dimensions as an indicator of cell proliferation. The system is based on a commercialized Boyden chamber plate; a through-hole was bored through a porous membrane of the chamber, and the pre-existing 0.4 m membrane pores were filled with parylene C. A HepG2 spheroid was immobilized onto the through-hole, separating the upper and lower compartments. Fluorescein (to verify the isolation between the compartments) and tirapazamine (TPZ; to treat only the lower part of the spheroid) were added to the upper and lower compartments, respectively. Since the transportation of fluorescein was blocked during treatment, i.e., the upper and lower compartments were isolated, it was confirmed that localized TPZ treatment was successfully conducted using the developed system. The effect of localized TPZ treatment on cell proliferation was estimated by measuring the maximum horizontal cross-sectional areas in the upper and lower parts of the spheroid by microscopic observations. This system can, thus, be used to perform localized anticancer drug treatment of tumor spheroids and evaluate the effect of drugs on cell proliferation.
PubMed: 31893010
DOI: 10.1063/1.5125650 -
Molecules (Basel, Switzerland) Oct 2019Benzimidazoles belong to a new class of bioreductive agents with cytotoxic activity towards solid tumor cells, especially in their first stage of growth, which is...
Benzimidazoles belong to a new class of bioreductive agents with cytotoxic activity towards solid tumor cells, especially in their first stage of growth, which is characterized by low oxygen concentration. Bioreductive agents represent a class of prodrugs that target hypoxic tumor cells. Their bioactivity depends on the reactivity of their functional chemical groups. Their efficacy requires metabolic reduction and subsequent generation of toxic prodrugs. Chemoresistance of tumor cells is a major problem for successful antitumor therapy for many types of tumors, especially for breast cancer. The present study was performed to assess the effect of the antiproliferation activity of the tested benzimidazoles by way of NF-κB expression inhibition. The activity of the tested compounds on T47D and MCF7 cells was examined by WST, western blot, NF-κB transactivation assay, and apoptotic cell population analysis. Compound 3 was highly cytotoxically active against T47D cells, especially in hypoxic conditions. Its IC of 0.31 ± 0.06 nM, although weaker than tirapazamine, was significantly higher than the other tested compounds (2.4-3.0 fold). The increased bax protein expression upon exposure to the tested compounds indicated intercellular apoptotic pathway activity, with tumor cell death by way of apoptosis. Increased bax protein synthesis and apoptotic cell dominance upon treatment, especially with N-oxide derivatives (92% apoptotic cells among T47D cell populations during treatment with compound 3), were correlated with each other. Additionally, both increased bax protein and decreased NF-κB protein expression supported antiproliferative activity via NF-κB-DNA binding inhibition associated with the tested compounds. Compound 3 appeared to be the strongest inhibitor of NF-κB expression in hypoxic conditions (the potency against NF-κB expression was about 75% of that of tirapazamine). The present studies involving this class of heterocyclic small molecules proved their potential usefulness in anticancer therapy as compounds be able to limit tumor cell proliferation and reverse drug resistance by NF-κB repression.
Topics: Benzimidazoles; Cell Death; Cell Line, Tumor; Cell Proliferation; Genes, Reporter; Humans; Inhibitory Concentration 50; NF-kappa B; Transcription, Genetic; bcl-2-Associated X Protein
PubMed: 31671914
DOI: 10.3390/molecules24213902 -
International Journal of Molecular... Sep 2019Derivatives of tirapazamine and other heteroaromatic oxides (ArN→O) exhibit promising antibacterial, antiprotozoal, and tumoricidal activities. Their action is...
Derivatives of tirapazamine and other heteroaromatic oxides (ArN→O) exhibit promising antibacterial, antiprotozoal, and tumoricidal activities. Their action is typically attributed to bioreductive activation and free radical generation. In this work, we aimed to clarify the mechanism(s) of aerobic mammalian cell cytotoxicity of ArN→O performing the parallel studies of their reactions with NADPH:cytochrome P-450 reductase (P-450R), adrenodoxin reductase/adrenodoxin (ADR/ADX), and NAD(P)H:quinone oxidoreductase (NQO1); we found that in P-450R and ADR/ADX-catalyzed single-electron reduction, the reactivity of ArN→O ( = 9) increased with their single-electron reduction midpoint potential (), and correlated with the reactivity of quinones. NQO1 reduced ArN→O at low rates with concomitant superoxide production. The cytotoxicity of ArN→O in murine hepatoma MH22a and human colon adenocarcinoma HCT-116 cells increased with their , being systematically higher than that of quinones. The cytotoxicity of both groups of compounds was prooxidant. Inhibitor of NQO1, dicoumarol, and inhibitors of cytochromes P-450 α-naphthoflavone, isoniazid and miconazole statistically significantly ( < 0.02) decreased the toxicity of ArN→O, and potentiated the cytotoxicity of quinones. One may conclude that in spite of similar enzymatic redox cycling rates, the cytotoxicity of ArN→O is higher than that of quinones. This is partly attributed to ArN→O activation by NQO1 and cytochromes P-450. A possible additional factor in the aerobic cytotoxicity of ArN→O is their reductive activation in oxygen-poor cell compartments, leading to the formation of DNA-damaging species similar to those forming under hypoxia.
Topics: Antineoplastic Agents; Biomarkers; Humans; Molecular Structure; NAD(P)H Dehydrogenase (Quinone); NADP; Oxidants; Oxidation-Reduction; Reactive Oxygen Species; Tirapazamine
PubMed: 31533349
DOI: 10.3390/ijms20184602 -
International Journal of Nanomedicine 2019Tumor metastasis is responsible for most cancer death worldwide, which lacks curative treatment. The objective of this study was to eliminate tumor and control the...
Tumor metastasis is responsible for most cancer death worldwide, which lacks curative treatment. The objective of this study was to eliminate tumor and control the development of tumor metastasis. Herein, we demonstrated a smart nano-enabled platform, in which 2-[2-[2-chloro-3-[(1,3-dihydro-3,3-dimethyl-1-propyl-2h-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl]ethenyl]-3,3-dimethyl-1-propylindolium iodide (IR780) and tirapazamine (TPZ) were co-loaded in poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL) to form versatile nanoparticles (PEG-PCL-IR780-TPZ NPs). The intelligence of the system was reflected in the triggered and controlled engineering. Specially, PEG-PCL not only prolonged the circulation time of IR780 and TPZ but also promoted tumor accumulation of nanodrugs through enhanced permeability and retention (EPR) effect. Moreover, reactive oxygen species (ROS) generated by IR780 armed by an 808 nm laser irradiation evoked a cargo release. Meanwhile, IR780, as a mitochondria-targeting phototherapy agent exacerbated tumor hypoxic microenvironment and activated TPZ for accomplishing hypoxia-activated chemotherapy. Most significantly, IR780 was capable of triggering immunogenic cell death (ICD) during the synergic treatment. ICD biomarkers as a "danger signal" accelerated dendritic cells (DCs) maturation, and subsequently activated toxic T lymphocytes. Eventually, antitumor immune responses stimulated by combinational phototherapy and hypoxia-activated chemotherapy revolutionized the current landscape of cancer treatment, strikingly inhibiting tumor metastasis and providing a promising prospect in the clinical application.
Topics: Animals; Antineoplastic Agents; Cell Death; Cell Hypoxia; Cell Line, Tumor; Cell Survival; Humans; Immunotherapy; Indoles; Liposomes; Mice, Inbred BALB C; Nanoparticles; Neoplasms; Photochemotherapy; Phototherapy; Polyethylene Glycols; Reactive Oxygen Species; Temperature; Tirapazamine; Tumor Burden; Tumor Microenvironment
PubMed: 31417257
DOI: 10.2147/IJN.S203383 -
Molecules (Basel, Switzerland) Jul 2019Extracellular acidification is an important feature of tumor microenvironments but has yet to be successfully exploited in cancer therapy. The reversal of the pH...
Extracellular acidification is an important feature of tumor microenvironments but has yet to be successfully exploited in cancer therapy. The reversal of the pH gradient across the plasma membrane in cells that regulate intracellular pH (pHi) has potential to drive the selective uptake of weak acids at low extracellular pH (pHe). Here, we investigate the dual targeting of low pHe and hypoxia, another key feature of tumor microenvironments. We prepared eight bioreductive prodrugs based on the benzotriazine di-oxide (BTO) nucleus by appending alkanoic or aminoalkanoic acid sidechains. The BTO acids showed modest selectivity for both low pHe (pH 6.5 versus 7.4, ratios 2 to 5-fold) and anoxia (ratios 2 to 8-fold) in SiHa and FaDu cell cultures. Related neutral BTOs were not selective for acidosis, but had greater cytotoxic potency and hypoxic selectivity than the BTO acids. Investigation of the uptake and metabolism of representative BTO acids confirmed enhanced uptake at low pHe, but lower intracellular concentrations than expected for passive diffusion. Further, the modulation of intracellular reductase activity and competition by the cell-excluded electron acceptor WST-1 suggests that the majority of metabolic reductions of BTO acids occur at the cell surface, compromising the engagement of the resulting free radicals with intracellular targets. Thus, the present study provides support for designing bioreductive prodrugs that exploit pH-dependent partitioning, suggesting, however, that that the approach should be applied to prodrugs with obligate intracellular activation.
Topics: Cell Hypoxia; Cell Line, Tumor; Chemical Phenomena; Dose-Response Relationship, Drug; Drug Design; Humans; Hydrogen-Ion Concentration; Models, Biological; Molecular Structure; Neoplasms; Oxidation-Reduction; Oxides; Prodrugs; Triazines
PubMed: 31295864
DOI: 10.3390/molecules24142524