ABSTRACT
BACKGROUND: Growth Differentiation Factor 15 (GDF15), a divergent member of the TGF-ß superfamily, signals via the hindbrain glial-derived neurotrophic factor receptor alpha-like and rearranged during transfection receptor co-receptor (GFRAL-RET) complex. In nonclinical species, GDF15 is a potent anorexigen leading to substantial weight loss. MBL949 is a half-life extended recombinant human GDF15 dimer. METHODS: MBL949 was evaluated in multiple nonclinical species and then in humans in two randomized and placebo-controlled clinical trials. In the Phase 1 first-in-human, single ascending dose trial MBL949 or placebo was injected subcutaneously to overweight and obese healthy volunteers (n=65) at doses ranging from 0.03 to 20 mg. In Phase 2, MBL949 or placebo was administered subcutaneously every other week for a total of 8 doses to obese participants (n=126) in five different dose regimens predicted to be efficacious based on data from the Phase 1 trial. RESULTS: In nonclinical species, MBL949 was generally safe and effective with reduced food intake and body weight in mice, rats, dogs, and monkeys. Weight loss was primarily from reduced fat, and metabolic endpoints improved. A single ascending dose study in overweight or obese healthy adults demonstrated mean terminal half-life of 18-22 days, and evidence of weight loss at the higher doses. In the Phase 2, weight loss was minimal following biweekly dosing of MBL949 for 14 weeks. MBL949 was safe and generally tolerated in humans over the dose range tested, adverse events of the gastrointestinal system were the most frequent observed. CONCLUSION: The prolonged half-life of MBL949 supports biweekly dosing in patients. MBL949 had an acceptable safety profile. The robust weight loss observed in nonclinical species did not translate to weight loss efficacy in humans. TRIAL REGISTRATION: ClinicalTrials.gov NCT05199090.
ABSTRACT
Madagascar periwinkle (Catharanthus roseus) is the sole source of the anticancer drugs vinblastine and vincristine, bisindole alkaloids derived from the dimerization of the terpenoid indole alkaloids vindoline and catharanthine. Full elucidation of the biosynthetic pathways of these compounds is a prerequisite for metabolic engineering efforts that will improve production of these costly molecules. However, despite the medical and commercial importance of these natural products, the biosynthetic pathways remain poorly understood. Here we report the identification and characterization of a C. roseus cDNA encoding an S-adenosyl-L-methionine-dependent N methyltransferase that catalyzes a nitrogen methylation involved in vindoline biosynthesis. Recombinant enzyme produced in Escherichia coli is highly substrate specific, displaying a strict requirement for a 2,3-dihydro bond in the aspidosperma skeleton. The corresponding gene transcript is induced in methyl jasmonate-elicited seedlings, along with the other known vindoline biosynthetic transcripts. Intriguingly, this unique N methyltransferase is most similar at the amino acid level to the plastidic γ-tocopherol C methyltransferases of vitamin E biosynthesis, suggesting an evolutionary link between these two functionally disparate methyltransferases.
Subject(s)
Alkaloids , Antineoplastic Agents, Phytogenic , Catharanthus/enzymology , Methyltransferases , Plant Proteins , Alkaloids/biosynthesis , Alkaloids/chemistry , Antineoplastic Agents, Phytogenic/biosynthesis , Antineoplastic Agents, Phytogenic/chemistry , Base Sequence , Catharanthus/genetics , Escherichia coli/genetics , Methylation , Methyltransferases/chemistry , Methyltransferases/genetics , Methyltransferases/metabolism , Molecular Sequence Data , Plant Proteins/biosynthesis , Plant Proteins/chemistry , Plant Proteins/genetics , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Substrate SpecificityABSTRACT
Strictosidine synthase triggers the formation of strictosidine from tryptamine and secologanin, thereby generating a carbon-carbon bond and a new stereogenic center. Strictosidine contains a tetrahydro-ß-carboline moiety - an important N-heterocyclic framework found in a range of natural products and synthetic pharmaceuticals. Stereoselective methods to produce tetrahydro-ß-carboline enantiomers are greatly valued. We report that strictosidine synthase from Ophiorrhiza pumila utilizes a range of simple achiral aldehydes and substituted tryptamines to form highly enantioenriched (ee >98%) tetrahydro-ß-carbolines via a Pictet-Spengler reaction. This is the first example of aldehyde substrate promiscuity in the strictosidine synthase family of enzymes and represents a first step towards developing a general biocatalytic strategy to access chiral tetrahydro-ß-carbolines.
ABSTRACT
The replacement of a t-butyl group with a trifluoromethyl group has profound effects on the biological profile of 1alpha,25-dihydroxyvitamin D(3) sulfone analogs. Investigation of whether the improved biological activities are due to steric and electronic factors of the trifluoromethyl group led to the design, synthesis and biological evaluation of two analogous alkyl sulfone molecules, methyl sulfone (AU-16-ene-25-SO(2)-CH(3)) and isopropyl sulfone (AU-16-ene-25-SO(2)-i-Pr). These alkyl sulfones are sterically comparable to, but electronically very different from a trifluoromethyl group. The syntheses, antiproliferative activities and calcemic activities of these new alkyl sulfones are presented herein. In comparing the in vitro antiproliferative profiles of the new alkyl sulfone 1alpha,25-dihydroxyvitamin D(3) analogs with the trifluoromethylsulfone and an analogous t-butyl sulfone, the activities increase in the following order: CH(3) < t-Bu approximately = i-Pr < CF(3). In contrast to the calcemic t-butyl sulfone, the novel alkyl sulfones and trifluoromethyl sulfone display desirable low calcemic levels.
Subject(s)
Calcium/metabolism , Cell Proliferation/drug effects , Sulfones/chemistry , Sulfones/pharmacology , Vitamin D/analogs & derivatives , Animals , Calcitriol/pharmacology , Cells, Cultured , Keratinocytes/cytology , Rats , Structure-Activity Relationship , Sulfones/chemical synthesis , Vitamin D/chemical synthesis , Vitamin D/chemistry , Vitamin D/pharmacology , Vitamins/pharmacologyABSTRACT
The biosynthetic pathways of plant natural products offer an abundance of knowledge to scientists in many fields. Synthetic chemists can be inspired by the synthetic strategies that nature uses to construct these compounds. Chemical and biological engineers are working to reprogram these biosynthetic pathways to more efficiently produce valuable products. Finally, biochemists and enzymologists are interested in the detailed mechanisms of the complex transformations involved in the construction of these natural products. Study of biosynthetic enzymes and pathways therefore has a wide-ranging impact. In recent years, many plant biosynthetic pathways have been characterized, particularly the pathways that are responsible for alkaloid biosynthesis. Here we highlight recently studied alkaloid biosynthetic enzymes that catalyze production of numerous complex medicinal compounds, as well as the specifier proteins in glucosinosolate biosynthesis, whose structure and mechanism of action are just beginning to be unraveled.
Subject(s)
Biological Products/metabolism , Plants/enzymology , Alkaloids/metabolism , Glucosinolates/metabolismABSTRACT
In four or five chemical steps from the 1,2,4-trioxane artemisinin, a new series of 23 trioxane dimers has been prepared. Eleven of these new trioxane dimers cure malaria-infected mice via oral dosing at 3 x 30 mg/kg. The clinically used trioxane drug sodium artesunate prolonged mouse average survival to 7.2 days with this oral dose regimen. In comparison, animals receiving no drug die typically on day 6-7 postinfection. At only 3 x 10 mg/kg oral dosing, seven dimers prolong the lifetime of malaria-infected mice to days 14-17, more than double the chemotherapeutic effect of sodium artesunate. Ten new trioxane dimers at only a single oral dose of 30 mg/kg prolong mouse average survival to days 8.7-13.7, and this effect is comparable to that of the fully synthetic trioxolane drug development candidate OZ277, which is in phase II clinical trials.
Subject(s)
Antimalarials/chemical synthesis , Artemisinins/chemical synthesis , Malaria/drug therapy , Animals , Antimalarials/chemistry , Antimalarials/pharmacology , Artemisinins/chemistry , Artemisinins/therapeutic use , Mice , Plasmodium berghei , Structure-Activity RelationshipABSTRACT
Novel fluorinated sulfone analogs of the hormone 1alpha,25-dihydroxyvitamin D(3) have been designed and synthesized in order to study the biological effects of fluorine incorporation at the terminus of the C,D-ring side chain. Although biologically active 26,27-hexafluorinated 1alpha,25-dihydroxyvitamin D(3) analogs have been synthesized previously, this investigation reports the first successful fluorinated series in which trifluoromethyl sulfone analogs present a favorable biological profile. This study shows that two new analogs featuring incorporation of a synthetically simple single trifluoromethyl sulfone group have significantly increased antiproliferative activity while causing desirably low in vivo calciuria relative to that of calcitriol. Incorporation of additional fluorines, as in a perfluorobutyl analog, results in a loss of antiproliferative activity.
Subject(s)
Calcitriol/chemistry , Fluorine/chemistry , Sulfones/chemistry , Vitamin D/analogs & derivatives , Animals , Calcium/urine , Cell Proliferation/drug effects , Molecular Structure , Rats , Vitamin D/chemical synthesis , Vitamin D/chemistry , Vitamin D/pharmacologyABSTRACT
Examination of conjugated ethylenic sulfones, sulfoxides, and esters in Michael-type addition reactions reveals, for the first time, that the size of the heteroatom-attached alkyl group affects the rate of conjugate addition. Molecular modeling strongly suggests that what are generally considered to be "remote" alkyl groups in -CbetaH=CalphaHS(O)n-alkyl systems and -CH2CbetaH=CalphaHCOO-alkyl systems are actually not remote from the beta-carbon atom of the Michael accepting unit. Molecular modeling clearly shows that the alkyl groups in these Michael acceptors shield the beta-carbons in the following order: Et