ABSTRACT
Prodrugs engineered for preferential activation in diseased versus normal tissues offer immense potential to improve the therapeutic indexes (TIs) of preclinical and clinical-stage active pharmaceutical ingredients that either cannot be developed otherwise or whose efficacy or tolerability it is highly desirable to improve. Such approaches, however, often suffer from trial-and-error design, precluding predictive synthesis and optimization. Here, using bromodomain and extra-terminal (BET) protein inhibitors (BETi)-a class of epigenetic regulators with proven anticancer potential but clinical development hindered in large part by narrow TIs-we introduce a macromolecular prodrug platform that overcomes these challenges. Through tuning of traceless linkers appended to a "bottlebrush prodrug" scaffold, we demonstrate correlation of in vitro prodrug activation kinetics with in vivo tumor pharmacokinetics, enabling the predictive design of novel BETi prodrugs with enhanced antitumor efficacies and devoid of dose-limiting toxicities in a syngeneic triple-negative breast cancer murine model. This work may have immediate clinical implications, introducing a platform for predictive prodrug design and potentially overcoming hurdles in drug development.
Subject(s)
Antineoplastic Agents/pharmacology , Drug Design , Prodrugs/pharmacology , Proteins/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Proliferation/drug effects , Drug Screening Assays, Antitumor , Humans , Macromolecular Substances/chemical synthesis , Macromolecular Substances/chemistry , Macromolecular Substances/pharmacology , Mammary Neoplasms, Experimental/drug therapy , Mammary Neoplasms, Experimental/metabolism , Mammary Neoplasms, Experimental/pathology , Mice , Molecular Structure , Prodrugs/chemical synthesis , Prodrugs/chemistry , Proteins/metabolismABSTRACT
At present there are no drugs for the treatment of chronic liver fibrosis that have been approved by the Food and Drug administration of the United States. Telmisartan, a small-molecule antihypertensive drug, displays antifibrotic activity, but its clinical use is limited because it causes systemic hypotension. Here, we report the scalable and convergent synthesis of macromolecular telmisartan prodrugs optimized for preferential release in diseased liver tissue. We optimized the release of active telmisartan in fibrotic liver to be depot-like (that is, a constant therapeutic concentration) through the molecular design of telmisartan brush-arm star polymers, and show that these lead to improved efficacy and to the avoidance of dose-limiting hypotension in both metabolically and chemically induced mouse models of hepatic fibrosis, as determined by histopathology, enzyme levels in the liver, intact-tissue protein markers, hepatocyte necrosis protection, and gene-expression analyses. In rats and dogs, the prodrugs are retained long-term in liver tissue and have a well-tolerated safety profile. Our findings support the further development of telmisartan prodrugs that enable infrequent dosing in the treatment of liver fibrosis.
Subject(s)
Angiotensin II Type 1 Receptor Blockers/therapeutic use , Drug Design , Liver Cirrhosis/drug therapy , Prodrugs/therapeutic use , Telmisartan/therapeutic use , Angiotensin II Type 1 Receptor Blockers/chemistry , Angiotensin II Type 1 Receptor Blockers/pharmacokinetics , Animals , Carbon Tetrachloride/toxicity , Disease Models, Animal , Female , Gene Expression Regulation/drug effects , Half-Life , Liver/metabolism , Liver Cirrhosis/chemically induced , Liver Cirrhosis/pathology , Male , Mice , Mice, Inbred BALB C , Polymers/chemistry , Prodrugs/chemistry , Prodrugs/pharmacokinetics , Rats , Rats, Sprague-Dawley , Telmisartan/chemistryABSTRACT
In the version of this Article originally published, the author Peter Blume-Jensen was not denoted as a corresponding author; this has now been amended and the author's email address has been added. The 'Correspondence and requests for materials' statement was similarly affected and has now been updated with the author's initials 'P.B-J.'
ABSTRACT
The human genome contains thousands of regions, including that of the telomere, that have the potential to form quadruplex structures. Many of these regions are potential targets for therapeutic intervention. There are many different folding patterns for quadruplex DNAs and the loops exhibit much more variation than do the quartets. The successful targeting of a particular quadruplex structure requires distinguishing that structure from all of the other quadruplex structures that may be present. A mix and measure fluorescent screening method has been developed, that utilizes multiple reporter molecules that bind to different features of quadruplex DNA. The reporter molecules are used in combination with DNAs that have a variety of quadruplex structures. The screening is based on observing the increase or decrease in the fluorescence of the reporter molecules. The selectivity of a set of test molecules has been determined by this approach.
Subject(s)
DNA/chemistry , Fluorescent Dyes/chemistry , G-Quadruplexes , Benzothiazoles/chemistry , Binding, Competitive , Carbocyanines/chemistry , Circular Dichroism , Ligands , Mesoporphyrins/chemistry , Spectrometry, FluorescenceABSTRACT
Circular dichroism, CD, spectra can be used to gain information about quadruplex structures of DNAs as well as the effects of sequence, cations, chemical modification and ligand binding on quadruplex structure. There is not yet a validated approach to calculate a CD spectrum from a quadruplex structure nor is their one to go from a CD spectrum to a structure. However, it is possible to empirically correlate CD spectra features with quadruplex structural type in many cases. In this article four case studies are presented to indicate the strengths and limitations of CD in investigations of the properties of quadruplex structures formed by telomere repeat sequences. The case studies include determination of the quadruplex structural type present as a function of potassium concentration, the effect of sequence on the equilibrium between quadruplex structural types as a function of potassium concentration, the effect of ligand binding on quadruplex structure and the effect of 5' phosphorylation on quadruplex structural type.