Development of multiplexing gene silencing system using conditionally induced polycistronic synthetic antisense RNAs in Escherichia coli.

Although efficient methods of gene silencing have been established in eukaryotes, many different techniques are still used in bacteria due to the lack of a standardized tool. Here, we developed a convenient and efficient method to downregulate the expression of a specific gene using ∼140 nucleotide RNA with a 24-nucleotide antisense region from an arabinose-inducible expression plasmid by taking Escherichia coli lacZ and phoA genes encoding ß-galactosidase and alkaline phosphatase, respectively, as target genes to evaluate the model. We examined the antisense RNA (asRNA) design, including targeting position, uORF stability elements at the 5'-end, and Hfq-binding module at the 3'-end, and inducer amount required to obtain effective experimental conditions for gene silencing. Furthermore, we constructed multiplexed dual-acting asRNA genes in the plasmid, which were transcribed as polycistronic RNA and were able to knockdown multiple target genes simultaneously. We observed the highest inhibition level of 98.6% when lacZ was targeted using the pMKN104 asRNA expression plasmid, containing a five times stronger PBAD -10 promoter sequence with no requirement of the Hfq protein for repression. These features allow the system to be utilized as an asRNA expression platform in many bacteria, besides E. coli, for gene regulation.

ß-D-glucan from marine yeast Debaryomyces hansenii BCS004 enhanced intestinal health and glucan-expressed receptor genes in Pacific red snapper Lutjanus peru.

Previous studies have shown that marine yeast Debaryomyces hansenii BCS004 (also known as Dh004) has a potential biotechnological application. The aim of this study was to investigate the structural characterization, antioxidant properties and possible health inductor of dietary ß-D-glucan BCS004. In this study, a glucan BCS004 was obtained containing (1-6)-branched (1-3)-ß-D-glucan with low molecular weight and a high purity of 90 and 91.7% for one and 4 h, respectively. ß-D-glucan BCS004 showed higher antioxidant activity, including DPPH radical and superoxide anion scavenging, ß-carotene bleaching inhibition, and iron chelation activity. An in vitro study showed that ß-D-glucan BCS004 was safe for peripheral blood leukocytes inducing proliferative effects. Moreover, in an in vivo study using ß-D-glucan BCS004 no histopathological damages or intestinal inflammation were observed in fish. The gene expression analysis highlighted that dietary ß-D-glucan BCS004 could also up-regulate glucan and macrophage receptor genes in intestine, such as C-type lectin (CTL) and macrophage mannose receptors (MMR). Overall, the results demonstrated that ß-D-glucan from D. hansenii BCS004 could be an immunostimulant with antioxidant properties and beneficial effects on intestinal health in fish.

DGIdb 3.0: a redesign and expansion of the drug-gene interaction database.

The drug-gene interaction database (DGIdb, www.dgidb.org) consolidates, organizes and presents drug-gene interactions and gene druggability information from papers, databases and web resources. DGIdb normalizes content from 30 disparate sources and allows for user-friendly advanced browsing, searching and filtering for ease of access through an intuitive web user interface, application programming interface (API) and public cloud-based server image. DGIdb v3.0 represents a major update of the database. Nine of the previously included 24 sources were updated. Six new resources were added, bringing the total number of sources to 30. These updates and additions of sources have cumulatively resulted in 56 309 interaction claims. This has also substantially expanded the comprehensive catalogue of druggable genes and anti-neoplastic drug-gene interactions included in the DGIdb. Along with these content updates, v3.0 has received a major overhaul of its codebase, including an updated user interface, preset interaction search filters, consolidation of interaction information into interaction groups, greatly improved search response times and upgrading the underlying web application framework. In addition, the expanded API features new endpoints which allow users to extract more detailed information about queried drugs, genes and drug-gene interactions, including listings of PubMed IDs, interaction type and other interaction metadata.

Novel Psychoactive Phenethylamines: Impact on Genetic Material.

Psychedelic and stimulating phenethylamines belong to the family of new psychoactive substances (NPS). The acute toxicity framework has begun to be investigated, while studies showing genotoxic potential are very limited or not available. Therefore, in order to fill this gap, the aim of the present work was to evaluate the genotoxicity by treating TK6 cells with 2C-H, 2C-I, 2C-B, 25B-NBOMe, and the popular 3,4-Methylenedioxymethylamphetamine (MDMA). On the basis of cytotoxicity and cytostasis results, we selected the concentrations (6.25-35 µM) to be used in genotoxicity analysis. We used the micronucleus (MN) as indicator of genetic damage and analyzed the MNi frequency fold increase by an automated flow cytometric protocol. All substances, except MDMA, resulted genotoxic; therefore, we evaluated reactive oxygen species (ROS) induction as a possible mechanism at the basis of the demonstrated genotoxicity. The obtained results showed a statistically significant increase in ROS levels for all genotoxic phenethylamines confirming this hypothesis. Our results highlight the importance of genotoxicity evaluation for a complete assessment of the risk associated also with NPS exposure. Indeed, the subjects who do not have hazardous behaviors or require hospitalization by using active but still "safe" doses could run into genotoxicity and in the well-known long-term effects associated.

Hydrogen sulfide regulates circadian-clock genes in C2C12 myotubes and the muscle of high-fat-diet-fed mice.

Hydrogen sulfide (H2S) is an endogenous novel gasotransmitter which is implicated in the pathophysiology of the metabolic syndrome. Core clock genes (CCG) and its controlled genes disruption is implicated in the progression of metabolic syndrome. We examined whether H2S has any effect on CCG in the skeletal muscle of mice fed a high-fat diet (HFD) and in myotubes. In the muscle of HFD-mice, the expression of H2S biosynthesis enzyme genes (CSE, CBS, and 3-Mpst) along with antioxidant genes (GCLC, GCLM, GSS, and GSR) involved in GSH biosynthesis and recycling were reduced significantly, but the oxidative stress (OS) increased. Expression of the CCG (Bmal1, Clock, RORα, Cry2, Per2) and clock-controlled genes (PPARγ, PGC-1α, RXRα) was downregulated, whereas the levels of PPARα mRNA were upregulated. Similar to that in the muscle of HFD-mice, in vitro myotubes exposed to high glucose or palmitate to mimic metabolic syndrome, showed an increased OS and decreased in CSE mRNA, H2S production and CCG mRNA levels were also downregulated. TNF and MCP-1 treatment on the myotubes was similar to that observed in HFD-muscle, with that the Rev-erbα mRNA was upregulated. Inhibition (siRNA/pharmacological inhibitors) of both CSE and GCLC (the rate-limiting enzyme in GSH biosynthesis) decreased H2S, and increased OS; Bmal1 and Clock mRNA levels were downregulated, while Rev-erbα increased significantly in these conditions. CSE KD myotubes were post-treated with an H2S donor partially restored the mRNA levels of core clock genes. These findings report that the deficiencies of H2S/GSH impair expression of CCG and treatment with H2S donor or GSH precursor exert a positive effect over CCG. Thus, suggest that H2S as a new endogenous factor for regulating circadian clock, and its donors could provide a novel chrono-pharmacological therapy to manage metabolic disorders.

Characterization of the responses of the caspase 2, 3, 6 and 8 genes to immune challenges and extracellular ATP stimulation in the Japanese flounder (Paralichthys olivaceus).

BACKGROUND: Caspases are a family of conserved intracellular cysteine-dependent aspartate-specific cysteine proteases that play important roles in regulating cell death and inflammation. Our previous study revealed the importance of the inflammatory caspase 1 gene in extracellular ATP-mediated immune signaling in Japanese flounder, Paralichthys olivaceus. To explore the potential roles of other caspases in P. olivaceus innate immunity, we extended our study by characterizing of the responses of four additional P. olivaceus caspase genes, termed JfCaspase 2, 3, 6 and 8, to inflammatory challenge and extracellular ATP stimulation. RESULTS: Sequence analysis revealed that the domain structures of all the Japanese flounder caspase proteins are evolutionarily conserved. Quantitative real-time PCR analysis showed that the JfCaspase 2, 3, 6 and 8 genes were expressed ubiquitously but at unequal levels in all examined Japanese flounder normal tissues. In addition, the basal gene expression levels of JfCaspase 2, 3, 6 and 8 were higher than those of JfCaspase 1 in both Japanese flounder head kidney macrophages (HKMs) and peripheral blood leukocytes (PBLs). Furthermore, immune challenge experiments showed that the inflammatory stimuli LPS and poly(I:C) significantly modulated the expression of the JfCaspase 2, 3, 6 and 8 genes in Japanese flounder immune cells. Finally, DNA fragmentation, associated with increased extracellular ATP-induced JfCaspase 2, 3, 6 and 8 gene expression and enzymatic activity, was inhibited by the caspase inhibitor Z-VAD-FMK in the HKMs. CONCLUSION: Our findings demonstrate broad participation of multiple caspase genes in response to inflammatory stimulation in Japanese flounder immune cells and provide new evidence for the involvement of caspase(s) in extracellular ATP-induced apoptosis in fish.

DGIdb 2.0: mining clinically relevant drug-gene interactions.

The Drug-Gene Interaction Database (DGIdb, www.dgidb.org) is a web resource that consolidates disparate data sources describing drug-gene interactions and gene druggability. It provides an intuitive graphical user interface and a documented application programming interface (API) for querying these data. DGIdb was assembled through an extensive manual curation effort, reflecting the combined information of twenty-seven sources. For DGIdb 2.0, substantial updates have been made to increase content and improve its usefulness as a resource for mining clinically actionable drug targets. Specifically, nine new sources of drug-gene interactions have been added, including seven resources specifically focused on interactions linked to clinical trials. These additions have more than doubled the overall count of drug-gene interactions. The total number of druggable gene claims has also increased by 30%. Importantly, a majority of the unrestricted, publicly-accessible sources used in DGIdb are now automatically updated on a weekly basis, providing the most current information for these sources. Finally, a new web view and API have been developed to allow searching for interactions by drug identifiers to complement existing gene-based search functionality. With these updates, DGIdb represents a comprehensive and user friendly tool for mining the druggable genome for precision medicine hypothesis generation.

Chicken interferome: avian interferon-stimulated genes identified by microarray and RNA-seq of primary chick embryo fibroblasts treated with a chicken type I interferon (IFN-α).

Viruses that infect birds pose major threats-to the global supply of chicken, the major, universally-acceptable meat, and as zoonotic agents (e.g. avian influenza viruses H5N1 and H7N9). Controlling these viruses in birds as well as understanding their emergence into, and transmission amongst, humans will require considerable ingenuity and understanding of how different species defend themselves. The type I interferon-coordinated response constitutes the major antiviral innate defence. Although interferon was discovered in chicken cells, details of the response, particularly the identity of hundreds of stimulated genes, are far better described in mammals. Viruses induce interferon-stimulated genes but they also regulate the expression of many hundreds of cellular metabolic and structural genes to facilitate their replication. This study focusses on the potentially anti-viral genes by identifying those induced just by interferon in primary chick embryo fibroblasts. Three transcriptomic technologies were exploited: RNA-seq, a classical 3'-biased chicken microarray and a high density, "sense target", whole transcriptome chicken microarray, with each recognising 120-150 regulated genes (curated for duplication and incorrect assignment of some microarray probesets). Overall, the results are considered robust because 128 of the compiled, curated list of 193 regulated genes were detected by two, or more, of the technologies.

ZINC 15--Ligand Discovery for Everyone.

Many questions about the biological activity and availability of small molecules remain inaccessible to investigators who could most benefit from their answers. To narrow the gap between chemoinformatics and biology, we have developed a suite of ligand annotation, purchasability, target, and biology association tools, incorporated into ZINC and meant for investigators who are not computer specialists. The new version contains over 120 million purchasable "drug-like" compounds--effectively all organic molecules that are for sale--a quarter of which are available for immediate delivery. ZINC connects purchasable compounds to high-value ones such as metabolites, drugs, natural products, and annotated compounds from the literature. Compounds may be accessed by the genes for which they are annotated as well as the major and minor target classes to which those genes belong. It offers new analysis tools that are easy for nonspecialists yet with few limitations for experts. ZINC retains its original 3D roots--all molecules are available in biologically relevant, ready-to-dock formats. ZINC is freely available at http://zinc15.docking.org.

The anti-tumor drug bleomycin preferentially cleaves at the transcription start sites of actively transcribed genes in human cells.

The genome-wide pattern of DNA cleavage at transcription start sites (TSSs) for the anti-tumor drug bleomycin was examined in human HeLa cells using next-generation DNA sequencing. It was found that actively transcribed genes were preferentially cleaved compared with non-transcribed genes. The 143,600 identified human TSSs were split into non-transcribed genes (82,596) and transcribed genes (61,004) for HeLa cells. These transcribed genes were further split into quintiles of 12,201 genes comprising the top 20, 20-40, 40-60, 60-80, and 80-100 % of expressed genes. The bleomycin cleavage pattern at highly transcribed gene TSSs was greatly enhanced compared with purified DNA and non-transcribed gene TSSs. The top 20 and 20-40 % quintiles had a very similar enhanced cleavage pattern, the 40-60 % quintile was intermediate, while the 60-80 and 80-100 % quintiles were close to the non-transcribed and purified DNA profiles. The pattern of bleomycin enhanced cleavage had peaks that were approximately 200 bp apart, and this indicated that bleomycin was identifying the presence of phased nucleosomes at TSSs. Hence bleomycin can be utilized to detect chromatin structures that are present at actively transcribed genes. In this study, for the first time, the pattern of DNA damage by a clinically utilized cancer chemotherapeutic agent was performed on a human genome-wide scale at the nucleotide level.

Fibroblast growth factor 21 regulates energy metabolism by activating the AMPK-SIRT1-PGC-1alpha pathway.

Fibroblast growth factor 21 (FGF21) has been identified as a potent metabolic regulator. Administration of recombinant FGF21 protein to rodents and rhesus monkeys with diet-induced or genetic obesity and diabetes exerts strong antihyperglycemic and triglyceride-lowering effects and reduction of body weight. Despite the importance of FGF21 in the regulation of glucose, lipid, and energy homeostasis, the mechanisms by which FGF21 functions as a metabolic regulator remain largely unknown. Here we demonstrate that FGF21 regulates energy homeostasis in adipocytes through activation of AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1), resulting in enhanced mitochondrial oxidative function. AMPK phosphorylation levels were increased by FGF21 treatment in adipocytes as well as in white adipose tissue from ob/ob mice. FGF21 treatment increased cellular NAD(+) levels, leading to activation of SIRT1 and deacetylation of its downstream targets, peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) and histone 3. Activation of AMPK and SIRT1 by FGF21 in adipocytes enhanced mitochondrial oxidative capacity as demonstrated by increases in oxygen consumption, citrate synthase activity, and induction of key metabolic genes. The effects of FGF21 on mitochondrial function require serine/threonine kinase 11 (STK11/LKB1), which activates AMPK. Inhibition of AMPK, SIRT1, and PGC-1alpha activities attenuated the effects of FGF21 on oxygen consumption and gene expression, indicating that FGF21 regulates mitochondrial activity and enhances oxidative capacity through an AMPK-SIRT1-PGC1alpha-dependent mechanism in adipocytes.

A systematic, genome-wide, phenotype-driven mutagenesis programme for gene function studies in the mouse.

As the human genome project approaches completion, the challenge for mammalian geneticists is to develop approaches for the systematic determination of mammalian gene function. Mouse mutagenesis will be a key element of studies of gene function. Phenotype-driven approaches using the chemical mutagen ethylnitrosourea (ENU) represent a potentially efficient route for the generation of large numbers of mutant mice that can be screened for novel phenotypes. The advantage of this approach is that, in assessing gene function, no a priori assumptions are made about the genes involved in any pathway. Phenotype-driven mutagenesis is thus an effective method for the identification of novel genes and pathways. We have undertaken a genome-wide, phenotype-driven screen for dominant mutations in the mouse. We generated and screened over 26,000 mice, and recovered some 500 new mouse mutants. Our work, along with the programme reported in the accompanying paper, has led to a substantial increase in the mouse mutant resource and represents a first step towards systematic studies of gene function in mammalian genetics.

Comparative gene expression profiles induced by PPARγ and PPARα/γ agonists in rat hepatocytes.

Species-differential toxic effects have been described with PPARα and PPARγ agonists between rodent and human liver. PPARα agonists (fibrates) are potent hypocholesterolemic agents in humans while they induce peroxisome proliferation and tumors in rodent liver. By contrast, PPARγ agonists (glitazones) and even dual PPARα/γ agonists (glitazars) have caused idiosyncratic hepatic and nonhepatic toxicities in human without evidence of any damage in rodent during preclinical studies. The mechanisms involved in such differences remain largely unknown. Several studies have identified the major target genes of PPARα agonists in rodent liver while no comprehensive analysis has been performed on gene expression changes induced by PPARγ and dual PPARα/γ agonists. Here, we investigated transcriptomes of rat hepatocytes after 24h treatment with two PPARγ (troglitazone and rosiglitazone) and two PPARα/γ (muraglitazar and tesaglitazar) agonists. Although, hierarchical clustering revealed a gene expression profile characteristic of each PPAR agonist class, only a limited number of genes was specifically deregulated by glitazars. Functional analyses showed that many genes known as PPARα targets were also modulated by both PPARγ and PPARα/γ agonists and quantitative differences in gene expression profiles were observed between these two classes. Moreover, most major genes modulated in rat hepatocytes were also found to be deregulated in rat liver after tesaglitazar treatment. Taken altogether, these results support the conclusion that differential toxic effects of PPARα and PPARγ agonists in rodent liver do not result from transcriptional deregulation of major PPAR target genes but rather from qualitative and/or quantitative differential responses of a small subset of genes.

Molecular identification of genes involved in testicular steroid synthesis and characterization of the response to gonadotropic stimulation in the Senegalese sole (Solea senegalensis) testis.

In male teleosts, testicular steroids are essential hormones for the regulation of spermatogenesis and their production is regulated by pituitary gonadotropins. In the Senegalese sole (Solea senegalensis), an economically important flatfish with semi-cystic and asynchronous spermatogenesis, the gonadotropic regulation of spermatogenesis, particularly regarding the production and regulation of testicular steroids, are not well understood. For this reason, we first cloned and characterized the response of several key genes for the production and action of testicular steroids to the in vivo administration of human chorionic gonadotropin (hCG) and, second, we investigated the transcriptomic effects of hCG in the Senegalese sole testis. We succeeded in cloning the full-length cDNAs for Steroidogenic Acute Regulatory protein (StAR), 3ß-hydroxysteroid dehydrogenase (3ß-HSD), 17ß-HSD and 20ß-HSD and a partial cDNA for the nuclear progesterone receptor. In this study we also identified a transcript encoding a protein with homology to StAR, which we named StAR-like, that could represent a new member of the StAR-related lipid transfer (START) family. All the cloned genes were expressed in the testis and their expression levels were significantly increased by the in vivo administration of hCG. The plasma levels of testosterone and 11-ketotestosterone also increased in response to hCG administration, likely as a result of the induction of the expression of steroidogenic enzymes by hCG. Furthermore, gene expression analysis by microarray identified 90 differentially expressed genes in the testis in response to hCG administration, including genes potentially involved in steroidogenesis, progression of spermatogenesis and germ cell maturation and cytoskeletal organization. Our results have identified for the first time a number of key genes involved in the regulation of steroid production and spermatogenesis in the Senegalese sole testis that are under gonadotropic control.

Nanomedicine-based delivery strategies for nucleic acid gene inhibitors in inflammatory diseases.

Thanks to their abilities to modulate the expression of virtually any genes, RNA therapeutics have attracted considerable research efforts. Among the strategies focusing on nucleic acid gene inhibitors, antisense oligonucleotides and small interfering RNAs have reached advanced clinical trial phases with several of them having recently been marketed. These successes were obtained by overcoming stability and cellular delivery issues using either chemically modified nucleic acids or nanoparticles. As nucleic acid gene inhibitors are promising strategies to treat inflammatory diseases, this review focuses on the barriers, from manufacturing issues to cellular/subcellular delivery, that still need to be overcome to deliver the nucleic acids to sites of inflammation other than the liver. Furthermore, key examples of applications in rheumatoid arthritis, inflammatory bowel, and lung diseases are presented as case studies of systemic, oral, and lung nucleic acid delivery.

Plasminogen activator inhibitor 1 and 2 are tumor necrosis factor/cachectin-responsive genes.

Human rTNF/Cachectin was shown to stimulate gene transcription of plasminogen activator inhibitor (PA1)-1 and PAI-2, and simultaneously suppress constitutive gene expression of tissue-type plasminogen activator (t-PA) in human fibrosarcoma cells. We propose that a TNF-mediated reprogramming of gene transcription induces, in appropriate target cells, an anti-fibrinolytic state, which may cooperate with the induction of procoagulant activity (tissue factor) to stabilize the fibrin deposits commonly found in inflamed tissue. PAI genes also provide a model system for a study of the molecular pathways underlying TNF-mediated signal transduction.

Alloantiserum-induced inhibition of migration inhibition factor production in immune response gene-controlled immune systems.

We have previously demonstrated that alloantisera prepared by reciprocal immunization of strain 2 and strain 13 guinea pigs specifically block stimulation of in vitro DNA synthesis in genetically controlled systems. In order to determine whether this blockade extends to other T-lymphocyte functions, we examined the effect of alloantisera on the production of migration inhibition factor (MIF). (2 x 13)F(1) guinea pigs were immunized with a DNP derivative of the copolymer of L-glutamic acid and L-lysine (DNP-GL) and with DNP guinea pig albumin (GPA). The response to the former is controlled by a 2-linked Ir gene while that to the latter is mainly controlled by a 13-linked Ir gene. MIF production was assayed by an indirect procedure in which the migrating cell population lacked the histocompatibility antigen against which the alloantiserum was directed. Our results showed that anti-2 serum blocked MIF production by F(1) cells in response to DNP-GL but not DNP-GPA while anti-13 serum had the opposite effect. These experiments show that expression of a second major T-cell function is specifically blocked by alloantisera and suggest that Ir-gene products may act as antigen recognition substances on more than one type of T cell.

Kappa B-type enhancers are involved in lipopolysaccharide-mediated transcriptional activation of the tumor necrosis factor alpha gene in primary macrophages.

We have explored the cis-acting elements necessary for the LPS-mediated activation of the mouse TNF-alpha promoter by transfecting a set of 5' deletion mutants linked to the CAT reporter gene into primary bone marrow-derived macrophages. A major drop in inducibility by LPS was seen upon deletion of a region mapping between nt -655 and nt -451. Gel retardation assays revealed that LPS induced the appearance in this region of several specific DNA-protein complexes mapping to sequence motifs with strong homology to the kappa B enhancer. Constructs containing two or more copies of one of the kappa B enhancer motifs linked to a heterologous promoter were inducible by LPS. Additional deletion of a region between nt -301 and nt -241, which contains a MHC class II-like "Y box" and formed a Y box-specific complex with a protein whose concentration was increased by LPS, caused a nearly complete loss of inducibility by LPS. We speculate that NF-kappa B and/or related proteins are involved in the LPS-induced transcriptional activation of the TNF-alpha gene, and that factors interacting with the Y box can additionally modulate the activity of the gene in macrophages.

Alloantiserum-mediated suppression of histocompatibility-linked Ir-gene-controlled immune responses. Suppressive effects of IgG fragments derived from alloantisera.

Fab, Fc, and F(ab)'(2) fragments were prepared by enzymatic hydrolysis of the IgG fraction of strain 13 antistrain 2 alloantisera. These fragments were not cytotoxic to lymphocytes bearing strain 2 histocompatibility antigens, but the Fab and F(ab)'(2) fragments retained functional combining sites as indicated by their ability to suppress the cytotoxicity mediated by the intact antistrain 2 antibodies. The F(ab)'(2) fragments were much more efficient as inhibitors in this system than the Fab fragments. F(ab)'(2) at 0.06 mg/ml and 0.45 mg/ml Fab produced comparable degrees of suppression. The F(ab)'(2) at 0.06 mg/ml completely suppressed DNP copolymer of L-glutamic acid and L-lysine (GL)-stimulated tritiated thymidine incorporation. The monovalent Fab at 0.45 mg/ml, however, had no significant effect on the in vitro responses to DNP-GL. Addition of the intact alloantisera can be delayed 3 h after initiation of the antigen-stimulated cultures with no loss of suppression. After a delay of 6 h 45% suppression was observed. The requirement for the divalent molecule and the observation that effective suppression of the in vitro responses is still obtained when the alloantiserum is added several hours after initiation of the cultures both suggest that the immunosuppression results from an active process affecting the lymphocyte membrane that renders the cell refractory to the antigenic stimulus.

Finasteride treatment alters MMP-2 and -9 gene expression and activity in the rat ventral prostate.

The safety of using finasteride as a prevention of prostate cancer is still under debate. In this study, we investigated the effects of finasteride on the location, gene expression and activities of matrix metalloproteinases -2 and -9, which are involved in the degradation of extracellular matrix components during tissue remodelling and prostate cancer progression, invasion and metastasis. Ventral prostates (VP) from Wistar rats treated with finasteride (25 mg/kg/day) for 7 and 30 days and age-matched controls were evaluated using histology, immunohistochemistry, semi-quantitative RT-PCR and gelatin zymography. Finasteride treatment reduced the epithelial immunostaining of MMP-2 but increased MMP-9 immunostaining in the epithelial cells and in the stroma. The mRNA expression of both MMP-2 and MMP-9 were significantly increased on day 7 of finasteride treatment, mainly for MMP-9 and returned to the control levels by day 30. However, gelatin zymography showed that MMP-9 activity was significantly increased on day 7 of finasteride treatment and remained elevated on day 30 (p < 0.05), while MMP-2 activity was reduced after 30 days of treatment. Finasteride increases MMP-9 and reduces MMP-2 activities in the prostate, which may affect negatively and positively both normal and tumoural prostatic cell behaviour during the treatment. Studies on expression of MMPs in the prostate during different androgen manipulation or cancer chemoprevention strategies can contribute to understand the tissue's overall response and clinical data.