Synthetic benzamide derivatives were investigated for their ability to inhibit histone deacetylase (HDA). In this study, one of the most active benzamide derivatives, MS-27-275, was examined with regard to its biological properties and antitumor efficacy. MS-27-275 inhibited partially purified human HDA and caused hyperacetylation of nuclear histones in various tumor cell lines. It behaved in a manner similar to other HDA inhibitors, such as sodium butyrate and trichostatin A; MS-27-275 induced p21 WAF1͞CIP1 and gelsolin and changed the cell cycle distribution, decrease of S-phase cells, and increase of G 1 -phase cells. The in vitro sensitivity spectrum of MS-27-275 against various human tumor cell lines showed a pattern different than that of a commonly used antitumor agent, 5-f luorouracil, and, of interest, the accumulation of p21 WAF1͞CIP1 tended to be faster and greater in the cell lines sensitive to MS-27-275. MS-27-275 administered orally strongly inhibited the growth in seven of eight tumor lines implanted into nude mice, although most of these did not respond to 5-f luorouracil. A structurally analogous compound to MS-27-275 without HDA-inhibiting activity showed neither the biological effects in cell culture nor the in vivo therapeutic efficacy. These results suggest that MS-27-275 acts as an antitumor agent through HDA inhibition and may provide a novel chemotherapeutic strategy for cancers insensitive to traditional antitumor agents.

Treatment of PC12 cells with either nerve growth factor (NGF), a differentiating factor, or epidermal growth factor (EGF), a mitogen, resulted in 7-15-fold activation of a protein kinase activity in cell extracts that phosphorylated microtubule-associated protein (MAP) 2 on serine and threonine residues in vitro. Both the NGFactivated kinase and the EGF-activated kinase could be partially purified by sequential chromatography on DEAE-cellulose, phenyl-Sepharose and hydroxylapatite, and were identical with each other in their chromatographic behavior, apparent molecular mass ( z 40 kDa) on gel filtration, substrate specificity, and phosphopeptide-mapping pattern of MAP2 phosphorylated by each kinase. Moreover, both kinases were found to be indistinguishable from a mitogen-activated MAP kinase previously described in growth-factor-stimulated or phorbol-ester-stimulated fibroblastic cells, based on the same criteria. Kinase assays in gels after SDS/ polyacrylamide gel electrophoresis revealed further that the NGF-or EGF-activated MAP kinase in PC12 cells, as well as the EGF-activated MAP kinase in fibroblastic 3Y1 cells resided in two closely spaced polypeptides with an apparent molecular mass of x 40 kDa. In addition, these MAP kinases were inactivated by either acid phosphatase treatment or protein phosphatase 2A treatment. These results indicate that MAP kinase may be activated through phosphorylation by a differentiating factor as well as by a mitogen. MAP kinase activation by EGF was protein kinase C independent; it reached an almost maximal level 1 min after EGF treatment and subsided rapidly within 30-60 min. On the other hand, NGF-induced activation of MAP kinase was partly protein kinase C dependent and continued for at least 2 -3 h.The PC12 pheochromocytoma cell line is a useful system for studying the mechanism of action of nerve growth factor (NGF). Exposure of PC12 cells to NGF results in differentiation of the cells, i.e. the conversion from a chromaffinlike phenotype into a sympathetic-neuron-like phenotype [I]. Although the detailed biochemical mechanisms of action of NGF are not known, it is well known that treatment with NGF induces the enhanced phosphorylation of a number of proteins in PC12 cells [2 -81.The mechanisms of mitogenic signal transduction evoked by mitogens such as epidermal growth factor (EGF) has been intensively investigated so far, and a phosphorylation cascade is thought to play an essential role in transduction ofmitogenic signals [9, 101. MAP kinase is one of the kinases involved in the phosphorylation cascade 111 -141. We have previously found that treatment with various mitogens including EGF, platelet-derived growth factor, fibroblast growth factor, insuCorrespondence to E. Nishida,

Newly synthesized benzamide derivatives were evaluated for their inhibitory activity against histone deacetylase. The structure of these derivatives was unrelated to the known inhibitors, and IC 50 values of the active compounds were in the range of 2-50 µM. Structure-activity relationship on the benzanilide moiety showed that the 2′-substituent, an amino or hydroxy group, was indispensable for inhibitory activity. Although the electronic influence of the substituent in the anilide moiety showed only a small effect on inhibitory activity, the steric factor in the anilide moiety, especially at positions 3′and 4′, played an important role in interaction with the enzyme. Among these benzamide derivatives, MS-275 (1), which showed significant antitumor activity in vivo, has been selected for further investigation.

Systemic sclerosis (SSc) is manifested by fibrosis, vasculopathy and immune dysregulation. So far, a unifying hypothesis underpinning these pathological events remains unknown. Given that SSc is a multifactorial disease caused by both genetic and environmental factors, we focus on the two transcription factors, which modulate the fibrotic reaction and are epigenetically suppressed in SSc dermal fibroblasts, Friend leukemia integration 1 (Fli1) and Krüppel-like factor 5 (KLF5). In addition to Fli1 silencing-dependent collagen induction, simultaneous knockdown of Fli1 and KLF5 synergistically enhances expression of connective tissue growth factor. Notably, mice with double heterozygous deficiency of Klf5 and Fli1 mimicking the epigenetic phenotype of SSc skin spontaneously recapitulate all the three features of SSc, including fibrosis and vasculopathy of the skin and lung, B cell activation, and autoantibody production. These studies implicate the epigenetic downregulation of Fli1 and KLF5 as a central event triggering the pathogenic triad of SSc.

The incidence of meniscal tear associated with ACL injury is higher in chronic cases; the number of medial meniscal tears is particularly high, many of which require meniscectomy. Early ACL reconstruction is recommended also for the prevention of secondary meniscal tear.

Takahashi et al. find that epithelial cell–conditional knockdown of transcription factor Fli1 in mice drives systemic autoimmunity derived from thymic defects as well as selective tissue fibrosis in the skin and esophagus, mimicking human scleroderma. This study unravels the unanswered question about the origin of autoimmunity and selective tissue fibrosis in this disease.

These results suggest that sPD-1 and sPD-L2 contribute to disease development in SSc via the regulation of cognate interactions with T cells and B cells.

Chemerin is down-regulated in SSc dermal fibroblasts by autocrine TGF-β, while it is up-regulated in SSc dermal blood vessels through endothelial Fli1 deficiency. Increased chemerin expression in dermal blood vessels may be associated with the development of digital ulcers in SSc.