Activin A is an important regulator of testicular and epididymal development and function, as well as inflammation and immunity. In the adult murine reproductive tract, activin A mRNA (Inhba) expression levels are highest in the caput epididymis and decrease progressively towards the distal vas deferens. The activin-binding protein, follistatin (FST), shows the opposite expression pattern, with exceptionally high levels of the Fst288 mRNA variant in the vas deferens. This unique pattern of expression suggests that activin A and follistatin, in particular FST288, play region-specific roles in regulating the epididymis and vas deferens. The cellular distribution of activin and follistatin and structural organization of the male reproductive tract was examined in wild-type and transgenic (TghFST315) mice lacking FST288. Compared to wild-type littermates, TghFST315 mice showed a 50% reduction in serum follistatin and a significant elevation of both activin A and B. Testicular, epididymal and seminal vesicle weights were reduced, but intra-testicular testosterone was normal. A decrease in the epididymal duct diameter in the corpus and thickening of the peritubular smooth muscle in the cauda, together with increased coiling of the proximal vas deferens, were observed in TghFST315 mice. No immune cell infiltrates were detected. Immunohistochemistry indicated that epithelial cells are the main source of activins and follistatin in the epididymis and vas deferens. Activin A, but not activin B, was also localized to sperm heads in the lumen of the epididymis and vas deferens. Expression of Inhba and another immunoregulatory gene, indoleamine-2,3-dioxygenase (Ido-1), was increased approximately twofold in the TghFST315 caput epididymis, but several other genes associated with immunoregulation, inflammation or fibrosis were unaffected. Our novel data indicate that disruption of follistatin expression has significant effects on the testis and epididymis, and suggest an association between activin A and indoleamine-2,3-dioxygenase in the caput epididymis, with implications for the epididymal immunoenvironment.

Abstract. Female mice lacking the follistatin gene but expressing a human follistatin-315 transgene (tghFST315) have reproductive abnormalities (reduced follicles, no corpora lutea and ovarian-uterine inflammation). We hypothesised that the absence of follistatin-288 causes the abnormal reproductive tract via both developmental abnormalities and abnormal ovarian activity. We characterised the morphology of oviducts and uteri in wild type (WT), tghFST315 and follistatinknockout mice expressing human follistatin-288 (tghFST288). The oviducts and uteri were examined in postnatal Day-0 and adult mice (WT and tghFST315 only) using histology and immunohistochemistry. Adult WT and tghFST315 mice were ovariectomised and treated with vehicle, oestradiol-17b (100 ng injection, dissection 24 h later) or progesterone (1 mg  three daily injections, dissection 24 h later). No differences were observed in the oviducts or uteri at birth, but abnormalities developed by adulthood. Oviducts of tghFST315 mice failed to coil, the myometrium was disorganised, endometrial gland number was reduced and oviducts and uteri contained abundant leukocytes. After ovariectomy, tghFST315 mice had altered uterine cell proliferation, and inflammation was maintained and exacerbated by oestrogen. These studies show that follistatin is crucial to postnatal oviductal-uterine development and function. Further studies differentiating the role of ovarian versus oviductal-uterine follistatin in reproductive tract function at different developmental stages are warranted.

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Earlier we generated novel derivatives of the hydroxamate-based histone deacetylase inhibitor (HDACi), Oxamflatin (Ox), which demonstrate considerable HDACi activity. Here the effects of one such derivative, Metacept-1 (MCT-1), alone or in combination with tamoxifen on mammary tumour growth have been assessed in a syngeneic orthotopic model. MCT-1 alone resulted in a trend towards inhibition of growth of 4T1.2 mammary tumours. Since the combination of MCT-1 and tamoxifen up-regulates estrogen receptor expression in 4T1.2 cells in vitro, we tested this combination and found a significant reduction in primary tumour growth over tamoxifen treatment alone. Taken together, these observations suggest that the novel HDACi MCT-1 may warrant further exploration in the treatment of estrogen receptor positive breast carcinoma, particularly when used in combination with conventional agents such as tamoxifen. ' UICCKey words: histone deacetylase inhibitor; breast cancer; tamoxifen Histone deacetylase inhibitors (HDACi) represent a novel, heterogeneous class of compounds that have significant therapeutic activity in the treatment of haematological malignancies, including cutaneous T-cell lymphoma.1-5 Additional pre-clinical and clinical studies support a role for HDACi in the treatment of solid tumours, with animal studies identifying considerable biological activity of HDACi 6,7 and early phase clinical studies indicating acceptable toxicity profiles and significant anti-tumour activity. 8,9 In addition, in vitro and clinical studies in solid tumours, including breast carcinoma, indicate that use of HDACi in combination with conventional chemotherapeutic agents may have significant therapeutic benefits over single agent treatment. 10,11The hydroxamate class of HDACi, including Trichostatin A, Oxamflatin, SAHA and LBH-589, represent one of several structurally diverse groups of HDACi, other structural classes include the cyclic peptides (e.g., depsipeptide), aliphatic acids (e.g., phenyl butyrate) and the benzamides (e.g., MS-275).12 In general, potent HDAC inhibitors of the hydroxamate class consist of a hydroxamic acid group, believed to be required for binding to the zinc active site of the HDAC enzyme, a six carbon linker, and a hydrophobic group (often aromatic) for surface-recognition. 13 We have shown that Metacept-1 (MCT-1), a methyl sulfonamide analogue of the known HDACi Oxamflatin, 14,15 is also a potent inhibitor of histone deacetylase at concentrations in the micromolar range. 16,17The mechanism(s) of action of HDACi either alone or in combination with conventional chemotherapeutic agents remains the subject of intense investigation. Although HDACi are known to modulate histone acetylation status and thus regulate transcription of many genes deemed critical to oncogenic and apoptotic processes, 2 numerous studies identify HDACi mediated modulation of the post-translational acetylation of proteins, including proteins associated with critical cellular and signalling events. 2,3 In the setting of breast cancer, es...