ABSTRACT
Isolated sternal fractures are very rare in children. Pain management is the method of choice, but surgery may be indicated in selected cases with dislocated fractures. However, the indication for open reduction of sternal fractures is discussed controversially. To the best of our knowledge, we present the first report of a child with displaced isolated sternal fracture who was successfully treated by conservative means using a vacuum bell.
Subject(s)
Closed Fracture Reduction/instrumentation , Fractures, Bone/therapy , Sternum/injuries , Child , Humans , Male , VacuumABSTRACT
AKR1C3 is a novel therapeutic target in castration-resistant prostate cancer (CRPC) and estrogen receptor (ER)-positive breast cancer because of its ability to produce testosterone and 17ß-estradiol intratumorally, thus promoting nuclear receptor signaling and tumor progression. A panel of CRPC, ER-positive breast cancer and high/low AKR1C3-expressing cell lines were treated with SN33638, a selective inhibitor of AKR1C3, in the presence of hormone or prostaglandin (PG) precursors, prior to evaluation of cell proliferation and levels of 11ß-PG F2α (11ß-PGF2α), testosterone, 17ß-estradiol, and prostate-specific antigen (PSA). A meta-analysis of AKR1C3 mRNA expression in patient samples was also conducted, which revealed that AKR1C3 mRNA was upregulated in CRPC, but downregulated in ER-positive breast cancer. 11ß-PGF2α and testosterone levels in the cell line panel correlated with AKR1C3 protein expression. SN33638 prevented 11ß-PGF2α formation in cell lines that expressed AKR1C3, but partially inhibited testosterone formation and subsequently cell proliferation and/or PSA expression only in high (LAPC4 AKR1C3-overexpressing cells) or moderate (22RV1) AKR1C3-expressing cell lines. SN33638 had little effect on 17ß-estradiol production or estrone-stimulated cell proliferation in ER-positive breast cancer cell lines. Although SN33638 could prevent 11ß-PGF2α formation, its ability to prevent testosterone and 17ß-estradiol production and their roles in CRPC and ER-positive breast cancer progression was limited due to AKR1C3-independent steroid hormone production, except in LAPC4 AKR1C3 cells where the majority of testosterone was AKR1C3-dependent. These results suggest that inhibition of AKR1C3 is unlikely to produce therapeutic benefit in CRPC and ER-positive breast cancer patients, except possibly in the small subpopulation of CRPC patients with tumors that have upregulated AKR1C3 expression and are dependent on AKR1C3 to produce the testosterone required for their growth.
ABSTRACT
Inhibitors of the aldo-keto reductase enzyme AKR1C3 are of interest as potential drugs for leukemia and hormone-related cancers. A series of non-carboxylate morpholino(phenylpiperazin-1-yl)methanones were prepared by palladium-catalysed coupling of substituted phenyl or pyridyl bromides with the known morpholino(piperazin-1-yl)methanone, and shown to be potent (IC50â¼100nM) and very isoform-selective inhibitors of AKR1C3. Lipophilic electron-withdrawing substituents on the phenyl ring were positive for activity, as was an H-bond acceptor on the other terminal ring, and the ketone moiety (as a urea) was essential. These structure-activity relationships are consistent with an X-ray structure of a representative compound bound in the AKR1C3 active site, which showed H-bonding between the carbonyl oxygen of the drug and Tyr55 and His117 in the 'oxyanion hole' of the enzyme, with the piperazine bridging unit providing the correct twist to allow the terminal benzene ring to occupy the lipophilic pocket and align with Phe311.
Subject(s)
3-Hydroxysteroid Dehydrogenases/antagonists & inhibitors , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Hydroxyprostaglandin Dehydrogenases/antagonists & inhibitors , 3-Hydroxysteroid Dehydrogenases/chemistry , 3-Hydroxysteroid Dehydrogenases/metabolism , Aldo-Keto Reductase Family 1 Member C3 , Catalytic Domain , Chemistry Techniques, Synthetic , Crystallography, X-Ray , Enzyme Inhibitors/chemical synthesis , Hydrogen Bonding , Hydroxyprostaglandin Dehydrogenases/chemistry , Hydroxyprostaglandin Dehydrogenases/metabolism , Inhibitory Concentration 50 , Models, Molecular , Molecular Structure , Morpholines/chemistry , Structure-Activity RelationshipABSTRACT
High expression of the aldo-keto reductase enzyme AKR1C3 in the human prostate and breast has implicated it in the development and progression of leukemias and of prostate and breast cancers. Inhibitors are thus of interest as potential drugs. Most inhibitors of AKR1C3 are carboxylic acids, whose transport into cells is likely dominated by carrier-mediated processes. We describe here a series of (piperidinosulfonamidophenyl)pyrrolidin-2-ones as potent (<100 nM) and isoform-selective non-carboxylate inhibitors of AKR1C3. Structure-activity relationships identified the sulfonamide was critical, and a crystal structure showed the 2-pyrrolidinone does not interact directly with residues in the oxyanion hole. Variations in the position, co-planarity or electronic nature of the pyrrolidinone ring severely diminished activity, as did altering the size or polarity of the piperidino ring. There was a broad correlation between the enzyme potencies of the compounds and their effectiveness at inhibiting AKR1C3 activity in cells.
