Objective. To characterize the role of histone deacetylase (HDAC) activity in rheumatoid arthritis (RA) and to evaluate the effects of MI192, a novel HDAC-3-selective inhibitor, compared with the established nonselective HDAC inhibitor trichostatin A (TSA), on proinflammatory cytokine production.Methods. Activity of HDAC and histone acetyltransferase was measured in peripheral blood mononuclear cells (PBMCs) from RA patients by spectrophotometric assay, prior to and after 12 weeks of etanercept therapy. The effects of HDAC inhibitor treatment on cytokine production in both RA and healthy PBMCs were assessed by enzyme-linked immunosorbent assay.Results. RA PBMCs exhibited significantly increased HDAC activity (P ‫؍‬ 0.007) compared to PBMCs from healthy individuals, and the increase was unaltered after 12 weeks of etanercept therapy. TSA was a potent inhibitor of tumor necrosis factor (TNF) and interleukin-6 (IL-6) production in both RA and healthy PBMCs and of interferon-␥ (IFN␥) production in healthy PBMCs; IFN␥ was not produced by RA PBMCs. MI192 inhibited TNF production at high concentrations and dose-dependently inhibited IL-6 in RA PBMCs but not healthy PBMCs, across a dose range of 10 M-5 nM.Conclusion. HDAC activity is dysregulated in RA PBMCs and is a potential target for therapeutic intervention, as it is not affected by conventional anti-TNF treatment with etanercept. Both the selective and the nonselective HDAC inhibitors (MI192 and TSA, respectively) were found to regulate cytokine production from PBMCs, but their effects were cell type and compound specific. HDAC inhibitors have potential in the treatment of RA, and HDAC-selective inhibition may improve the therapeutic margin of safety; however, further clinical characterization and evaluation for adverse effects is needed.

Bazedoxifene (BZA) is a third-generation selective estrogen receptor modulator (SERM) that has been approved for the prevention and treatment of postmenopausal osteoporosis. It has antitumor activity; however, its mechanism of action remains unclear. In the present study, we characterized the effects of BZA and several other SERMs on the proliferation of hormone-dependent MCF-7 and T47D breast cancer cells and hormone-independent MCF-7:5C and MCF-7:2A cells and examined its mechanism of action in these cells. We found that all of the SERMs inhibited the growth of MCF-7, T47D, and MCF-7:2A cells; however, only BZA and fulvestrant (FUL) inhibited the growth of hormone-independent MCF-7:5C cells. Cell cycle analysis revealed that BZA and FUL induced G 1 blockade in MCF-7:5C cells; however, BZA down-regulated cyclin D1, which was constitutively overexpressed in these cells, whereas FUL suppressed cyclin A. Further analysis revealed that small interfering RNA knockdown of cyclin D1 reduced the basal growth of MCF-7:5C cells, and it blocked the ability of BZA to induce G 1 arrest in these cells. BZA also down-regulated estrogen receptor-␣ (ER␣) protein by increasing its degradation and suppressing cyclin D1 promoter activity in MCF-7:5C cells. Finally, molecular modeling studies demonstrated that BZA bound to ER␣ in an orientation similar to raloxifene; however, a number of residues adopted different conformations in the induced-fit docking poses compared with the experimental structure of ER␣-raloxifene. Together, these findings indicate that BZA is distinct from other SERMs in its ability to inhibit hormone-independent breast cancer cell growth and to regulate ER␣ and cyclin D1 expression in resistant cells.

The preparation of 21.24-dioxacorroles by condensation of dipyrromethane-5,5'-dicarboxylic acids with 5,5'-diformyl-2.2'-bifuryl or bis-(5-formyl-2-furyl) sulphide is described. It is suggested that the latter reaction involves a non-aromatic meso-thia-macrocyclic intermediate which loses sulphur by a disrotatory cyclisation to a thiiran intermediate followed by cheletropic loss of sulphur. Some evidence for this proposal is provided by the preparation of meso-thiaphlorins and a study of their thermolyses to give corroles. Further examples of sulphur extrusion from a meso-dithiaphlorin, to give a meso-thiacorrole, are given and rate enhancements, in the sulphur extrusion process, which are observed in metal complexes are discussed. Some electrophilic deuteriation studies on the 21,24-dioxacorroles are reported.

Histone deacetylase (HDAC) inhibitors prevent neural cell death in in vivo models of cerebral ischaemia, brain injury and neurodegenerative disease. One mechanism by which HDAC inhibitors may do this is by suppressing the excessive inflammatory response of chronically activated microglia. However, the molecular mechanisms underlying this anti-inflammatory effect and the specific HDAC responsible are not fully understood. Recent data from in vivo rodent studies have shown that inhibition of class I HDACs suppresses neuroinflammation and is neuroprotective. In our study, we have identified that selective HDAC inhibition with inhibitors apicidin, MS-275 or MI-192, or specific knockdown of HDAC1 or 2 using siRNA, suppresses the expression of cytokines interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in BV-2 murine microglia activated with lipopolysaccharide (LPS). Furthermore, we found that in the absence of HDAC1, HDAC2 is up-regulated and these increased levels are compensatory, suggesting that these two HDACs have redundancy in regulating the inflammatory response of microglia. Investigating the possible underlying anti-inflammatory mechanisms suggests an increase in protein expression is not important. Taken together, this study supports the idea that inhibitors selective towards HDAC1 or HDAC2, may be therapeutically useful for targeting neuroinflammation in brain injuries and neurodegenerative disease.

Rhinacanthin-M, -N and -Q, natural products isolated from the medicinal plant Rhinacanthus nasutus, and 39 novel naphthoquinone esters have been synthesized in excellent yield by esterification of naphthoquinone-3-(propan-3'-ols) with benzoic or naphthoic acids. Almost all the naphthoquinone esters that contain a C-3 hydroxy group showed significant cytotoxicities against KB, HeLa, and HepG2 cell lines. In contrast, ester derivatives lacking the C-3 hydroxy group were inactive to the cancer cell lines. Two methyl substituents on the C-2' of propyl chain conferred more potent cytotoxicity than when there is only one or no methyl group. Naphthoate esters exhibited greater cytotoxicity than benzoate esters. Computer modeling has been done to obtain a first look at the mode of action in connection with these observations.