Transforming growth factor-beta in benign and malignant prostate

Induction of Reactive Bone Stromal Fibroblasts in 3D Models of Prostate Cancer Bone Metastases

A dynamic interplay between prostate cancer (PCa) cells and reactive bone stroma modulates the growth of metastases within the bone microenvironment. Of the stromal cells, metastasis-associated fibroblasts (MAFs) are known to contribute but are the least studied cell type in PCa tumour progression. It is the aim of the current study to establish a biologically relevant 3D in vitro model that mimics the cellular and molecular profiles of MAFs found in vivo. Using 3D in vitro cell culture models, the bone-derived fibroblast cell line, HS-5, was treated with conditioned media from metastatic-derived PCa cell lines, PC3 and MDA-PCa 2b, or mouse-derived fibroblasts 3T3. Two corresponding reactive cell lines were propagated: HS5-PC3 and HS5-MDA, and evaluated for alterations in morphology, phenotype, cellular behaviour, plus protein and genomic profiles. HS5-PC3 and HS5-MDA displayed distinct alterations in expression levels of N-Cadherin, non-functional E-Cadherin, alpha-smooth muscle actin (α-SMA), Tenascin C, and vimentin, along with transforming growth factor receptor expression (TGF β R1 and R2), consistent with subpopulations of MAFs reported in vivo. Transcriptomic analysis revealed a reversion of HS5-PC3 towards a metastatic phenotype with an upregulation in pathways known to regulate cancer invasion, proliferation, and angiogenesis. The exploitation of these engineered 3D models could help further unravel the novel biology regulating metastatic growth and the role fibroblasts play in the colonisation process.

Regulatory roles of ferroptosis-related non-coding RNAs and their research progress in urological malignancies

Ferroptosis is a new type of cell death characterized by damage to the intracellular microenvironment, which causes the accumulation of lipid hydroperoxide and reactive oxygen species to cause cytotoxicity and regulated cell death. Non-coding RNAs (ncRNAs) play an important role in gene expression at the epigenetic, transcriptional, and post-transcriptional levels through interactions with different DNAs, RNAs, or proteins. Increasing evidence has shown that ferroptosis-related ncRNAs are closely related to the occurrence and progression of several diseases, including urological malignancies. Recently, the role of ferroptosis-associated ncRNAs (long non-coding RNAs, micro RNAs, and circular RNAs) in the occurrence, drug resistance, and prognosis of urological malignancies has attracted widespread attention. However, this has not yet been addressed systematically. In this review, we discuss this issue as much as possible to expand the knowledge and understanding of urological malignancies to provide new ideas for exploring the diagnosis and treatment of urological malignancies in the future. Furthermore, we propose some challenges in the clinical application of ferroptosis-associated ncRNAs.

Crosstalk between miRNA and PI3K/AKT/mTOR signaling pathway in cancer

Phosphoinositide-3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway is one of the most important proliferative signaling pathways with critical undeniable function in various aspects of cancer initiation/progression, including proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. On the other hand, numerous genetic alterations in the key genes involved in the PI3K/AKT/mTOR signaling pathway have been identified in multiple solid and hematological tumors. In addition, accumulating recent evidences have demonstrated a reciprocal interaction between this signaling pathway and microRNAs, a large group of small non-coding RNAs. Therefore, in this review, it was attempted to discuss about the interaction between key components of PI3K/AKT/mTOR signaling pathway with various miRNAs and their importance in cancer biology.

Peri-Prostatic Adipocyte-Released TGFβ Enhances Prostate Cancer Cell Motility by Upregulation of Connective Tissue Growth Factor

Periprostatic adipose tissue (PPAT) has emerged as a key player in the prostate cancer (PCa) microenvironment. In this study, we evaluated the ability of PPAT to promote PCa cell migration, as well as the molecular mechanisms involved.

METHODS

We collected conditioned mediums from in vitro differentiated adipocytes isolated from PPAT taken from PCa patients during radical prostatectomy. Migration was studied by scratch assay.

RESULTS

Culture with CM of human PPAT (AdipoCM) promotes migration in two different human androgen-independent (AI) PCa cell lines (DU145 and PC3) and upregulated the expression of CTGF. SB431542, a well-known TGFβ receptor inhibitor, counteracts the increased migration observed in presence of AdipoCM and decreased CTGF expression, suggesting that a paracrine secretion of TGFβ by PPAT affects motility of PCa cells.

CONCLUSIONS

Collectively, our study showed that factors secreted by PPAT enhanced migration through CTGF upregulation in AI PCa cell lines. These findings reveal the potential of novel therapeutic strategies targeting adipocyte-released factors and TGFβ/CTGF axis to fight advanced PCa dissemination.

IMUNOMARCAÇÃO DE TGF-β EM PRÓSTATAS CANINAS NORMAIS E COM LESÕES PROLIFERATIVAS

Resumo O fator de crescimento transformador-β (TGF-β), um mediador do crescimento prostático, induz a angiogênese e inibe a proliferação celular. Neste estudo, esse marcador foi utilizado com o objetivo de avaliar sua imunomarcação no tecido normal e com lesões proliferativas benignas, pré-neoplásicas e neoplásicas da próstata canina. Para isso, foram selecionadas 54 glândulas com histomorfologia normal, hiperplasia prostática benigna (HPB) epitelial, HPB estromal, atrofia inflamatória proliferativa (PIA), neoplasia intraepitelial prostática (PIN) e carcinoma, utilizadas para a confecção de um bloco de microarranjo tecidual (Tissue Microarray - TMA). As lâminas de TMA foram submetidas à técnica de imunoistoquímica com o anticorpo anti-TGF-β, sendo avaliada a intensidade de imunomarcação nas células epiteliais e estromais. Houve imunomarcação de TGF-β no tecido normal e naqueles com lesões proliferativas. Maior imunomarcação de TGF-β foi constatada nas células do tecido prostático normal e com HPB, enquanto as células prostáticas com PIA, PIN e carcinoma exibiram menor imunomarcação dessa citocina, o que sugere a ação do TGF-β na manutenção da homeostase do tecido normal e com lesão proliferativa benigna e na progressão das lesões proliferativas pré-malignas e malignas da próstata canina.

Specific expression pattern of tissue cytokines analyzed through the Surface Acoustic Wave technique is associated with age-related spontaneous benign prostatic hyperplasia in rats

The aim of the study reported herein was to evaluate the suitability of the Surface Acoustic Wave (SAW) technique as a possible diagnostic tool in benign prostatic hyperplasia (BPH). Moreover, for the first time, the BPH model was a totally physiological using naturally aged rats with spontaneous, age-related BPH instead of the pharmacologically induced models usually used. Eighteen male Wistar rats were distributed according to their age: 6 weeks (young), 12 weeks (adult) and 12 months (old) old. Prostate gland was removed and analyzed by mini-arrays, Western blotting (WB) and SAW techniques. Mini-arrays indicated that there were significant differences in the expression of 29/34 inflammation-related cytokines. WB was carried out to confirm the results after selection of 4 cytokines from which one showed no changes, namely PDGF-AA, and the other three, which significantly increase in older animals, were CD86, β-NGF and VEGF. Notwithstanding, WB of old rats yielded confusing results due to an anomalous migration of proteins, dismissing this technique as an useful tool in these animals. Accurate results in old rats were uniquely obtained by using the SAW technique. Thus, SAW analysis showed that there were not differences among groups in the amount of PDGF-AA. On the contrary, SAW analysis showed that amounts of CD86, β-NGF and VEGF in old rats were 2.0, 1.9 and 5.7-fold higher than that from young ones, respectively. These results indicate that SAW is a highly accurate technique for determining changes in the cytokines expression in BPH.

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Diagnosis of prostate alterations can be improved by using the SAW technique.

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Study of prostate alterations can be optimized by using an age-related animal model.

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VEGF is a sensitive marker of bening prostatic hyperplasia.

TGF-β1 stimulates migration of type II endometrial cancer cells by down-regulating PTEN via activation of SMAD and ERK1/2 signaling pathways

PTEN acts as a tumor suppressor primarily by antagonizing the PI3K/AKT signaling pathway. PTEN is frequently mutated in human cancers; however, in type II endometrial cancers its mutation rate is very low. Overexpression of TGF-β1 and its receptors has been reported to correlate with metastasis of human cancers and reduced survival rates. Although TGF-β1 has been shown to regulate PTEN expression through various mechanisms, it is not yet known if the same is true in type II endometrial cancer. In the present study, we show that treatment with TGF-β1 stimulates the migration of two type II endometrial cancer cell lines, KLE and HEC-50. In addition, TGF-β1 treatment down-regulates both mRNA and protein levels of PTEN. Overexpression of PTEN or inhibition of PI3K abolishes TGF-β1-stimulated cell migration. TGF-β1 induces SMAD2/3 phosphorylation and knockdown of common SMAD4 inhibits the suppressive effects of TGF-β1 on PTEN mRNA and protein. Interestingly, TGF-β1 induces ERK1/2 phosphorylation and pre-treatment with a MEK inhibitor attenuates the suppression of PTEN protein, but not mRNA, by TGF-β1. This study provides important insights into the molecular mechanisms mediating TGF-β1-induced down-regulation of PTEN and demonstrates an important role of PTEN in the regulation of type II endometrial cancer cell migration.

The Role of Testosterone in the Treatment of Castration-Resistant Prostate Cancer

Most men with metastatic prostate cancer who are treated with androgen deprivation therapy will eventually develop castration-resistant disease. In this review, we examine the molecular mechanisms that constitute castration resistance and how these processes may be exploited using testosterone-based therapies. We detail how the utilization of superphysiologic doses of testosterone at regular intervals, followed by a rapid clearance of testosterone through continued chemical castration, also known as bipolar androgen therapy, offers an especially promising therapeutic approach. We investigate the historical basis for this modality, detail recent early-phase clinical trials that have demonstrated the feasibility and efficacy of this treatment, and describe an ongoing clinical trial comparing this modality to a currently accepted standard of care, enzalutamide, for castration-resistant prostate cancer. Finally, we explore how this treatment modality will continue to be refined in the future.

Loss of SPDEF and gain of TGFBI activity after androgen deprivation therapy promote EMT and bone metastasis of prostate cancer

Androgen deprivation therapy (ADT) targeting the androgen receptor (AR) is a standard therapeutic regimen for treating prostate cancer. However, most tumors progress to metastatic castration-resistant prostate cancer after ADT. We identified the type 1, 2, and 4 collagen-binding protein transforming growth factor-β (TGFβ)-induced protein (TGFBI) as an important factor in the epithelial-to-mesenchymal transition (EMT) and malignant progression of prostate cancer. In prostate cancer cell lines, AR signaling stimulated the activity of the transcription factor SPDEF, which repressed the expression of TGFBI ADT, AR antagonism, or overexpression of TGFBI inhibited the activity of SPDEF and enhanced the proliferation rates of prostate cancer cells. Knockdown of TGFBI suppressed migration and proliferation in cultured cells and reduced prostate tumor growth and brain and bone metastasis in xenograft models, extending the survival of tumor-bearing mice. Analysis of prostate tissue samples collected before and after ADT from the same patients showed that ADT reduced the nuclear abundance of SPDEF and increased the production of TGFBI. Our findings suggest that induction of TGFBI promotes prostate cancer growth and metastasis and can be caused by dysregulation or therapeutic inhibition of AR signaling.

A New Oleanolic Acid Derivative against CCl₄-Induced Hepatic Fibrosis in Rats

A novel hepatoprotective oleanolic acid derivative, 3-oxours-oleana-9(11), 12-dien-28-oic acid (Oxy-Di-OA), has been reported. In previous studies, we found that Oxy-Di-OA presented the anti-HBV (Hepatitis B Virus) activity (IC₅₀ = 3.13 µg/mL). Remarkably, it is superior to lamivudine in the inhibition of the rebound of the viral replication rate. Furthermore, Oxy-Di-OA showed good performance of anti-HBV activity in vivo. Some studies showed that liver fibrosis may affiliate with HBV gene mutations. In addition, the anti-hepatic fibrosis activity of Oxy-Di-OA has not been studied. Therefore, we evaluated the protective effect of Oxy-Di-OA against carbon tetrachloride (CCl₄)-induced liver injury in rats. Daily intraperitoneally administration of Oxy-Di-OA prevented the development of CCl₄-induced liver fibrosis, which was evidenced by histological study and immunohistochemical analysis. The entire experimental protocol lasted nine weeks. Oxy-Di-OA significantly suppressed the increases of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (p < 0.05). Furthermore, Oxy-Di-OA could prevent expression of transforming growth factor β1 (TGF-β1). It is worth noting that the high-dose group Oxy-Di-OA is superior to bifendate in elevating hepatic function. Compared to the model group, Oxy-Di-OA in the high-dose group and low-dose group can significantly reduce the liver and spleen indices (p < 0.05). The acute toxicity test showed that LD₅₀ and a 95% confidence interval (CIs) value of Oxy-Di-OA were 714.83 mg/kg and 639.73–798.73 mg/kg via intraperitoneal injection in mice, respectively. The LD₅₀ value of Oxy-Di-OA exceeded 2000 mg/kg via gavage in mice. In addition, a simple and rapid high performance liquid chromatography-ultraviolet (HPLC-UV) method was developed and validated to study the pharmacokinetic characteristics of the compound. After single-dose oral administration, time to reach peak concentration of Oxy-Di-OA (C_max = 8.18 ± 0.66 μg/mL) was 10 ± 2.19 h; the elimination half-life and area under the concentration-time curve from t = 0 to the last time of Oxy-Di-OA was 2.19 h and 90.21 μg·h/mL, respectively.

Seminal plasma transforming growth factor-β, activin A and follistatin fluctuate within men over time

STUDY QUESTION

Do seminal plasma transforming growth factor-β (TGFB) cytokines vary within individuals over time, and does this relate to sperm parameters, age or prior abstinence?

SUMMARY ANSWER

Activin A and follistatin, and to a lesser extent TGFB1, TGFB2 and TGFB3, vary within individuals over time, in association with duration of abstinence.

WHAT IS ALREADY KNOWN

Seminal plasma TGFB cytokines can influence sperm function and reproductive success through interactions with the female reproductive tract after coitus. Over time, individual sperm parameters fluctuate considerably. Whether seminal fluid TGFB cytokines vary similarly, and the determinants of any variance, is unknown.

STUDY DESIGN, SIZE, DURATION

Between two and seven semen samples were collected from each of 14 fertile donors at 6-10 week intervals over the course of 12 months, then seminal plasma cytokines and sperm parameters were measured.

PARTICIPANTS/MATERIALS, SETTING AND METHOD

The concentrations and total amounts per ejaculate of TGFB1, TGFB2, TGFB3, activin A and follistatin were determined using commercial assays. Sperm parameters were assessed according to WHO IV standards. Mixed model analysis was utilised to determine the relative contribution of between- and within-individual factors to the variance. Relationships between cytokines and sperm parameters, as well as effect of age and duration of abstinence, were investigated by correlation analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

Within-individual variability contributed to the total variance for all cytokines and sperm parameters, and was a stronger determinant than between-individual variability for activin A and follistatin as well as for total sperm concentration and sperm motility. Positive correlations between each of the three TGFB isoforms, and activin and follistatin, suggest co-regulation of synthesis. Duration of abstinence influenced total content of TGFB1, TGFB2, activin A and follistatin. TGFB1 correlated inversely with age.

LIMITATIONS, REASONS FOR CAUTION

A limited number of donors from a single clinic were investigated. Clinical information on BMI, nutrition, smoking and other lifestyle factors was unavailable. Further studies are required to determine whether the findings can be generalised to larger populations and different ethnicities.

WIDER IMPLICATIONS OF THE FINDINGS

These data reveal substantial variation over time in seminal fluid cytokines and indicate that repeated analyses are required to gain precise representative data on an individual's status. Within-individual variation in seminal fluid components should be taken into account when investigating seminal fluid cytokines.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the National Health and Medical Research Council of Australia, ID453556 and APP1041332. The authors have no competing interests to disclose.

The relationship of seminal transforming growth factor-β1 and interleukin-18 with reproductive success in women exposed to seminal plasma during IVF/ICSI treatment

It has been proposed that the transforming growth factor (TGF)-β1 present in seminal plasma (SP) triggers a female immune response favorable for implantation. We hypothesize that seminal interleukin (IL)-18, a cytokine that can potentially cause implantation failure, interferes with the beneficial effect of TGF-β1. This study aims to determine whether the levels of seminal TGF-β1 and IL-18 are associated with reproductive outcomes in patients exposed to SP during in vitro fertilization (IVF) or IVF with intracytoplasmic sperm injection (ICSI). A prospective study, which included 71 couples undergoing IVF/ICSI was carried out. Female patients were exposed to their partners' SP via timed intercourse before the day of ovum pick-up (OPU) and also subjected to intravaginal SP application just after OPU. Quantitative measurements of total TGF-β1 (active plus latent) as well as IL-18 were determined by FlowCytomix™ technology in the SP to be used for intravaginal applications. Comparison of SP cytokine profiles between pregnant and non-pregnant groups revealed that pregnancy was correlated with a lower concentration of IL-18 (P=0.018) and lower content per ejaculate for both of IL-18 (P=0.0003) and TGF-β1 (P=0.047). The ratio of TGF-β1-to-IL-18 concentration was significantly higher in the pregnant than in the non-pregnant group (P=0.026). This study supports the notion that two key cytokines TGF-β1 and IL-18, both present in SP are associated with reproductive outcomes in female patients exposed to SP during IVF/ICSI treatment.

JunD Is Required for Proliferation of Prostate Cancer Cells and Plays a Role in Transforming Growth Factor-β (TGF-β)-induced Inhibition of Cell Proliferation

TGF-β inhibits proliferation of prostate epithelial cells. However, prostate cancer cells in advanced stages become resistant to inhibitory effects of TGF-β. The intracellular signaling mechanisms involved in differential effects of TGF-β during different stages are largely unknown. Using cell line models, we have shown that TGF-β inhibits proliferation in normal (RWPE-1) and prostate cancer (DU145) cells but does not have any effect on proliferation of prostate cancer (PC3) cells. We have investigated the role of Jun family proteins (c-Jun, JunB, and JunD) in TGF-β effects on cell proliferation. Jun family members were expressed at different levels and responded differentially to TGF-β treatment. TGF-β effects on JunD protein levels, but not mRNA levels, correlated with its effects on cell proliferation. TGF-β induced significant reduction in JunD protein in RWPE-1 and DU145 cells but not in PC3 cells. Selective knockdown of JunD expression using siRNA in DU145 and PC3 cells resulted in significant reduction in cell proliferation, and forced overexpression of JunD increased the proliferation rate. On the other hand, knockdown of c-Jun or JunB had little, if any, effect on cell proliferation; overexpression of c-Jun and JunB decreased the proliferation rate in DU145 cells. Further studies showed that down-regulation of JunD in response to TGF-β treatment is mediated via the proteasomal degradation pathway. In conclusion, we show that specific Jun family members exert differential effects on proliferation in prostate cancer cells in response to TGF-β, and inhibition of cell proliferation by TGF-β requires degradation of JunD protein.

Growth factors mediated cell signalling in prostate cancer progression: Implications in discovery of anti-prostate cancer agents

Cancer is one of the leading causes of mortality amongst world's population, in which prostate cancer is one of the most encountered malignancies among men. Globally, it is the sixth leading cause of cancer-related death in men. Prostate cancer is more prevalent in the developed world and is increasing at alarming rates in the developing countries. Prostate cancer is mostly a very sluggish progressing disease, caused by the overproduction of steroidal hormones like dihydrotestosterone or due to over-expression of enzymes such as 5-α-reductase. Various studies have revealed that growth factors play a crucial role in the progression of prostate cancer as they act either by directly elevating the level of steroidal hormones or upregulating enzyme efficacy by the active feedback mechanism. Presently, treatment options for prostate cancer include radiotherapy, surgery and chemotherapy. If treatment is done with prevailing traditional chemotherapy; it leads to resistance and development of androgen-independent prostate cancer that further complicates the situation with no cure option left. The current review article is an attempt to cover and establish an understanding of some major signalling pathways intervened through survival factors (IGF-1R), growth factors (TGF-α, EGF), Wnt, Hedgehog, interleukin, cytokinins and death factor receptor which are frequently dysregulated in prostate cancer. This will enable the researchers to design and develop better therapeutic strategies targeting growth factors and their cross talks mediated prostate cancer cell signalling.

Transforming growth factor-β promotes prostate bone metastasis through induction of microRNA-96 and activation of the mTOR pathway

Transforming growth factor-β (TGFβ) is enriched in the bone matrix and serves as a key factor in promoting bone metastasis in cancer. In addition, TGFβ signaling activates mammalian target of rapamycin (mTOR) functions, which is important for the malignant progression. Here, we demonstrate that TGFβ regulates the level of microRNA-96 (miR-96) through Smad-dependent transcription and that miR-96 promotes the bone metastasis in prostate cancer. The enhanced effects in cellular growth and invasiveness suggest that miR-96 functions as an oncomir/and metastamir. Supporting this idea, we identified a downstream target of the TGFβ-miR-96 signaling pathway to be AKT1S1 mRNA, whose translated protein is a negative regulator of mTOR kinase. Our findings provide a novel mechanism accounting for the TGFβ signaling and bone metastasis.

Cooperative effects of EGF, FGF, and TGF-β1 in prostate stromal cells are different from responses to single growth factors

AIMS

Stromal growth is critical for prostate enlargement during benign prostatic hyperplasia (BPH). While responses of prostate cells to single growth factors have been well characterized, responses to multiple growth factors at once are poorly understood. Here, we examined the effects of combinations between epidermal growth factor (EGF), fibroblast growth factor (FGF), and transforming growth factor-β1 (TGF-β1) in human prostate stromal cells.

MAIN METHODS

EGF, FGF, and TGF-β1 were applied to WPMY-1 cells, an immortalized, non-malignant line of stromal cells from the human prostate. Hypertrophic responses were assessed by protein/DNA ratio, and cyclin D1 mRNA by RT-PCR. Expression of EGF, FGF, and TGF-β1 and their receptors in human prostate tissue was analyzed by RT-PCR, Western blot, and fluorescence staining.

KEY FINDINGS

Hypertrophic responses to single growth factors and combinations were similar. Combinations showed additive effects on cyclin D1 mRNA. Combination of EGF with TGF-β1, but not EGF or TGF-β1 alone, caused assembly of cells to a new two-dimensional structure, being characterized by dense aggregates connected by branches of few cells. EGF and TGF-β1 were detected together in human prostates. Receptors for EGF and TGF-β colocalized on stromal cells in human prostates.

SIGNIFICANCE

Responses of prostate stromal cells to combinations of EGF, FGF, and TGF-β1 may be quantitatively different, qualitatively different, or similar to responses to single growth factors. The combination of EGF and TGF-β1, but not EGF or TGF-β1 alone, induces aggregation of prostate stromal cells, which may be relevant for morphogenesis.

Latent TGF-β1 is compartmentalized between blood and seminal plasma of HIV-positive men and its activation in semen is negatively correlated with viral load and immune activation

PROBLEM

Semen is the primary medium for sexual transmission of HIV-1 and contains high concentrations of TGF-β1, but its role in regulating HIV-mediated immune activation is unclear.

METHOD OF STUDY

TGF-β1 and sCD14 were compared in blood plasma (BP) and seminal plasma (SP) from HIV-uninfected and infected, antiretroviral therapy (ART)-naive and ART-treated men and in THP-1 cells following exposure to HIV-1. The relationship between TGF-β1 and sCD14 was determined by Spearman correlation.

RESULTS

Active and latent forms of TGF-β1 were compartmentalized between BP and SP. Highest active TGF-β1 levels were present in SP of ART-naïve chronic-infected men and decreased following ART treatment. Latent TGF-β1 was upregulated in BP following HIV infection, and highest levels were observed in BP of acute-infected men. Similar expression trends were observed between latent TGF-β1 and sCD14 in BP. A significant negative correlation was observed between active TGF-β1, sCD14, and semen viral load in ART-naive men.

CONCLUSION

TGF-β1 is compartmentalized between blood and semen, possibly co-expressed with sCD14 by activated monocytes/macrophages in BP as a result of HIV infection. Conversion of latent TGF-β1 into its active form could contribute to regulation of viral load and immune activation in the male genital tract, but depends on the stage of infection.

Mysteries of TGF-β Paradox in Benign and Malignant Cells

TGF-β regulates a wide range of biological functions including embryonic development, wound healing, organogenesis, immune modulation, and cancer progression. Interestingly, TGF-β is known to inhibit cell growth in benign cells but promote progression in cancer cells; this phenomenon is known as TGF-β paradox. To date, the mechanism of this paradox still remains a scientific mystery. In this review, we present our experience, along with the literature, in an attempt to answer this mystery. First, we observed that, on TGF-β engagement, there is a differential activation of Erk between benign and cancer cells. Since activated Erk is a major mediator in tumor progression and metastasis, a differentially activated Erk represents the answer to this mystery. Second, we identified a key player, PP2A-B56α, which is differentially recruited by the activated type I TGF-β receptor (TBRI) in benign and tumor cells, resulting in differential Erk activation. Finally, TGF-β stimulation leads to suppressed TBRs in tumor cells but not in benign cells. This differentially suppressed TBRs triggers differential recruitment of PP2A-B56α and, thus, differential activation of Erk. The above three events explain the mysteries of TGF-β paradox. Understanding the mechanism of TGF-β paradox will help us to predict indolent from aggressive cancers and develop novel anti-cancer strategies.

TGF-β cascade regulation by PPP1 and its interactors -impact on prostate cancer development and therapy

Protein phosphorylation is a key mechanism by which normal and cancer cells regulate their main transduction pathways. Protein kinases and phosphatases are precisely orchestrated to achieve the (de)phosphorylation of candidate proteins. Indeed, cellular health is dependent on the fine-tune of phosphorylation systems, which when deregulated lead to cancer. Transforming growth factor beta (TGF-β) pathway involvement in the genesis of prostate cancer has long been established. Many of its members were shown to be hypo- or hyperphosphorylated during the process of malignancy. A major phosphatase that is responsible for the vast majority of the serine/threonine dephosphorylation is the phosphoprotein phosphatase 1 (PPP1). PPP1 has been associated with the dephosphorylation of several proteins involved in the TGF-β cascade. This review will discuss the role of PPP1 in the regulation of several TGF-β signalling members and how the subversion of this pathway is related to prostate cancer development. Furthermore, current challenges on the protein phosphatases field as new targets to cancer therapy will be addressed.

The role of prostatic inflammation biomarkers in the diagnosis of prostate diseases

Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are chronic conditions, which are hormone-dependent and epidemiologically associated with prostate inflammation. As a large number of studies have demonstrated, the stimulation of T-cells at the level of prostatic chronic inflammatory infiltrates is followed by stromal and epithelial cell proliferation. The aim of this review is to present the actual level of knowledge in the field of prostatic immune response and chronic inflammation, and to analyze the relationships between chronic inflammation and BPH/PCa. The most studied prostatic inflammation biomarkers detected in biological fluids are also presented, together with their potential roles in the diagnosis and prognosis of prostatic disease.

Prostate cancer: the need for biomarkers and new therapeutic targets

Prostate cancer (PCa) incidence and mortality have decreased in recent years. Nonetheless, it remains one of the most prevalent cancers in men, being a disquieting cause of men's death worldwide. Changes in many cell signaling pathways have a predominant role in the onset, development, and progression of the disease. These include prominent pathways involved in the growth, apoptosis, and angiogenesis of the normal prostate gland, such as androgen and estrogen signaling, and other growth factor signaling pathways. Understanding the foundations of PCa is leading to the discovery of key molecules that could be used to improve patient management. The ideal scenario would be to have a panel of molecules, preferably detectable in body fluids, that are specific and sensitive biomarkers for PCa. In the early stages, androgen deprivation is the gold standard therapy. However, as the cancer progresses, it eventually becomes independent of androgens, and hormonal therapy fails. For this reason, androgen-independent PCa is still a major therapeutic challenge. By disrupting specific protein interactions or manipulating the expression of some key molecules, it might be possible to regulate tumor growth and metastasis formation, avoiding the systemic side effects of current therapies. Clinical trials are already underway to assess the efficacy of molecules specially designed to target key proteins or protein interactions. In this review, we address that recent progress made towards understanding PCa development and the molecular pathways underlying this pathology. We also discuss relevant molecular markers for the management of PCa and new therapeutic challenges.

Re-adapting T cells for cancer therapy: from mouse models to clinical trials

Adoptive T-cell therapy involves the isolation, expansion, and reinfusion of T lymphocytes with a defined specificity and function as a means to eradicate cancer. Our research has focused on specifying the requirements for tumor eradication with antigen-specific T cells and T cells transduced to express a defined T-cell receptor (TCR) in mouse models and then translating these strategies to clinical trials. Our design of T-cell-based therapy for cancer has reflected efforts to identify the obstacles that limit sustained effector T-cell activity in mice and humans, design approaches to enhance T-cell persistence, develop methods to increase TCR affinity/T-cell functional avidity, and pursue strategies to overcome tolerance and immunosuppression. With the advent of genetic engineering, a highly functional population of T cells can now be rapidly generated and tailored for the targeted malignancy. Preclinical studies in faithful and informative mouse models, in concert with knowledge gained from analyses of successes and limitations in clinical trials, are shaping how we continue to develop, refine, and broaden the applicability of this approach for cancer therapy.

Regulatory interactions between androgens, Hoxb5, and TGF β signaling in murine lung development

Androgens enhance airway branching but delay alveolar maturation contributing to increased respiratory morbidity in prematurely born male infants. Hoxb5 protein positively regulates airway branching in developing lung. In other organs, androgen regulation intersects with Hox proteins and TGFβ-SMAD signaling, but these interactions have not been studied in the lung. We hypothesized that androgen alteration of airway branching early in lung development requires Hoxb5 expression and that these androgen-Hoxb5 interactions occur partially through regional changes in TGFβ signaling. To evaluate acute effects of androgen and TGFβ on Hoxb5, E11 whole fetal mouse lungs were cultured with dihydrotestosterone (DHT) with/without Hoxb5 siRNA or TGFβ inhibitory antibody. Chronic in utero DHT exposure was accomplished by exposing pregnant mice to DHT (subcutaneous pellet) from E11 to E18. DHT's ability to enhance airway branching and alter phosphorylated SMAD2 cellular localization was partially dependent on Hoxb5. Hoxb5 inhibition also changed the cellular distribution of SMAD7 protein. Chronic in utero DHT increased Hoxb5 and altered SMAD7 mesenchymal localization. TGFβ inhibition enhanced airway branching, and Hoxb5 protein cellular localization was more diffuse. We conclude that DHT controls lung airway development partially through modulation of Hoxb5 protein expression and that this level of regulation involves interactions with TGFβ signaling.

Autophagy in prostate cancer and androgen suppression therapy

The role of autophagy is known to be highly complex and context-dependent, leading to both cancer suppression and progression in several tumors including melanoma, breast and prostate cancer. In the present review, recent advances in an understanding of the involvement of autophagy in prostate cancer treatment are described. The regulatory effects of androgens on prostate cancer cell autophagy are particularly discussed in order to highlight the effects of autophagy modulation during androgen deprivation. A critical evaluation of the studies examined in the present review suggests the attractive possibility of autophagy inhibition combined with hormonal therapy as a promising approach for prostate cancer treatment.

Cell-intrinsic abrogation of TGF-β signaling delays but does not prevent dysfunction of self/tumor-specific CD8 T cells in a murine model of autochthonous prostate cancer

Adoptive T cell therapy (ACT) for the treatment of established cancers is actively being pursued in clinical trials. However, poor in vivo persistence and maintenance of antitumor activity of transferred T cells remain major problems. TGF-β is a potent immunosuppressive cytokine that is often expressed at high levels within the tumor microenvironment, potentially limiting T cell-mediated antitumor activity. In this study, we used a model of autochthonous murine prostate cancer to evaluate the effect of cell-intrinsic abrogation of TGF-β signaling in self/tumor-specific CD8 T cells used in ACT to target the tumor in situ. We found that persistence and antitumor activity of adoptively transferred effector T cells deficient in TGF-β signaling were significantly improved in the cancerous prostate. However, over time, despite persistence in peripheral lymphoid organs, the numbers of transferred cells in the prostate decreased and the residual prostate-infiltrating T cells were no longer functional. These findings reveal that TGF-β negatively regulates the accumulation and effector function of transferred self/tumor-specific CD8 T cells and highlight that, when targeting a tumor Ag that is also expressed as a self-protein, additional substantive obstacles are operative within the tumor microenvironment, potentially hampering the success of ACT for solid tumors.

Mechanisms of prostate atrophy after LHRH antagonist cetrorelix injection: an experimental study in a rat model of benign prostatic hyperplasia

In the present study, we investigated the roles of TGF-β signaling pathway in a rat benign prostatic hyperplasia (BPH) model treated with cetrorelix. TGF-β1 and c-Myc expression were measured by qRT-PCR and Western blotting in the proximal and distal region of ventral prostatic lobes, respectively. We observed that treatment with cetrorelix led to a significant reduction of ventral prostate weight in a dose-dependent manner. In the proximal region, after cetrorelix treatment, the expression of TGF-β1 was dramatically increased (P<0.05), while the expression of c-Myc was significantly decreased (P<0.05). In comparison with the control group, the cetrorelix groups had more TUNEL-positive cells. Our findings strongly suggest that the TGF-β signaling pathway may be one of the major causes responsible for prostate volume reduction in BPH rats after cetrorelix treatment.

Suppressed prostate epithelial development with impaired branching morphogenesis in mice lacking stromal fibromuscular androgen receptor

Using the cre-loxP system, we generated a new mouse model [double stromal androgen receptor knockout (dARKO)] with selectively deleted androgen receptor (AR) in both stromal fibroblasts and smooth muscle cells, and found the size of the anterior prostate (AP) lobes was significantly reduced as compared with those from wild-type littermate controls. The reduction in prostate size of the dARKO mouse was accompanied by impaired branching morphogenesis and partial loss of the infolding glandular structure. Further dissection found decreased proliferation and increased apoptosis of the prostate epithelium in the dARKO mouse AP. These phenotype changes were further confirmed with newly established immortalized prostate stromal cells (PrSC) from wild-type and dARKO mice. Mechanistically, IGF-1, placental growth factor, and secreted phosphoprotein-1 controlled by stromal AR were differentially expressed in PrSC-wt and PrSC-ARKO. Moreover, the conditioned media (CM) from PrSC-wt promoted prostate epithelium growth significantly as compared with CM from PrSC-dARKO. Finally, adding IGF-1/placental growth factor recombinant proteins into PrSC-dARKO CM was able to partially rescue epithelium growth. Together, our data concluded that stromal fibromuscular AR could modulate epithelium growth and maintain cellular homeostasis through identified growth factors.

Regulation of TGF-β1 expression by androgen deprivation therapy of prostate cancer

In this paper we studied the in vivo neoadjuvant Androgen Deprivation Therapy (ADT) effect on the expression of TGF-β1 and its receptor Tβ-RII. Mechanisms of androgen dependence are critical to understanding prostate cancer progression to androgen independence associated with disease mortality, and TGF-β is thought to support prostatic apoptosis as its expression coincides with androgen ablation in benign and cancer tissues. Increase of both mRNA and protein level were shown for the first time only in the patients who underwent neoadjuvant ADT for 1-month. This transient increase of TGF-β expression after androgen ablation suggested cooperation of the pathways in prostate regression. Since no alteration was observed in the gene transcriptional activity, the molecular mechanism of this cooperation, probably act at the post-transcriptional level. TGF-β1 and Tβ-RII specific signals were co-localized within the neoplastic prostate epithelium. Our results suggests that the androgens deprivation by means of ADT for 1-month, involves a shift of the TGF-β1 mechanism in prostate cancer, suggesting that the TGF-β1 promotes prostate epithelial cell proliferation and inhibits apoptosis in a autocrine way.

Transforming growth factor β1 increase of hydroxysteroid dehydrogenase proteins is partly suppressed by red clover isoflavones in human primary prostate cancer-derived stromal cells

Transforming growth factor β1 (TGF-β1) increases dehydro-epiandrosterone (DHEA) metabolism to androgens and prostate-specific antigen (PSA) in a prostate tissue model where stromal (6S) cells and epithelial (LAPC-4) cells are cocultured. Red clover (RC) isoflavones inhibits transforming growth factor (TGF)-β-induced androgenicity. Mechanisms controlling those activities were explored. Three hydroxysteroid dehydrogenases (HSDs), 3β-HSD, HSD-17β1 and HSD-17β5 involved in metabolizing DHEA to testosterone (TESTO) were investigated. Individual depletion of HSDs in 6S cells significantly reduced TGF-β1/DHEA-induced PSA in LAPC-4 cells in cocultures. Monomer amounts of 3β-HSD were similar without or with TGF-β1 in both cell types but aggregates of 3β-HSD in 6S cells were much higher than those in LAPC-4 cells and were upregulated by TGFβ in 6S cells. Basal and TGF-β1-treated levels of HSD-17β1 and HSD-17β5 in LAPC-4 cells were significantly lower than in 6S cells, whereas levels of HSD-17β1 but not HSD-17β5 were TGFβ inducible. 6S cell HSD genes expression induced by TGFβ or androgen signaling was insignificant to contribute TGF-β1/DHEA-upregulated protein levels of HSDs. RC decreased TGF-β1- upregulation of aggregates of 3β-HSD but not HSD-17β1. Depletion of TGFβ receptors (TGFβ Rs) reduced TGF-β1/DHEA-upregulated HSDs and TESTO. Immunoprecipitation studies demonstrated that TGF-β1 disrupted associations of TGFβ Rs/HSDs aggregates, whereas RC suppressed the dissociations of aggregates of 3β-HSD but not HSD-17β1 from the receptors. Given that TGFβ Rs are recycled with or without ligand, TGF-β1-induced disassociation of the HSDs from TGFβ Rs may increase stability and activity of the HSDs. These data suggest a pathway connecting overproduction of TGFβ with increased PSA in prostate cancer.

Tgf-β1 expression as a biomarker of poor prognosis in prostate cancer

OBJECTIVE

To evaluate the correlation between transforming growth factor beta (TGF-β1) expression and prognosis in prostate cancer.

PATIENTS AND METHODS

TGF-β1 expression levels were analyzed using the quantitative real-time polymerase chain reaction to amplify RNA that had been isolated from fresh-frozen malignant and benign tissue specimens collected from 89 patients who had clinically localized prostate cancer and had been treated with radical prostatectomy. The control group consisted of li patients with benign prostate hyperplasia. The expression levels of TGF-β1 were compared between the groups in terms of Gleason scores, pathological staging, and prostate-specific antigen serum levels.

RESULTS

In the majority of the tumor samples, TGF-β1 was underexpressed 67.0% of PCa patients. The same expression pattern was identified in benign tissues of patients with prostate cancer. Although most cases exhibited underexpression of TGF-β1, a higher expression level was found in patients with Gleason scores ≥ 7 when compared to patients with Gleason scores < 7(p = 0.002). Among the 26 cases of TGF-β1 overexpression, 92.3% had poor prognostic features.

CONCLUSIONS

TGF-β1 was underexpressed in prostate cancers; however, higher expression was observed in tumors with higher Gleason scores, which suggests that TGF-β1 expression may be a useful prognostic marker for prostate cancer. Further studies of clinical specimens are needed to clarify the role of TGF-β1 in prostate carcinogenesis.

Tgf-β1 expression as a biomarker of poor prognosis in prostate cancer

OBJECTIVE

To evaluate the correlation between transforming growth factor beta (TGF-β1) expression and prognosis in prostate cancer.

PATIENTS AND METHODS

TGF-β1 expression levels were analyzed using the quantitative real-time polymerase chain reaction to amplify RNA that had been isolated from fresh-frozen malignant and benign tissue specimens collected from 89 patients who had clinically localized prostate cancer and had been treated with radical prostatectomy. The control group consisted of li patients with benign prostate hyperplasia. The expression levels of TGF-β1 were compared between the groups in terms of Gleason scores, pathological staging, and prostate-specific antigen serum levels.

RESULTS

In the majority of the tumor samples, TGF-β1 was underexpressed 67.0% of PCa patients. The same expression pattern was identified in benign tissues of patients with prostate cancer. Although most cases exhibited underexpression of TGF-β1, a higher expression level was found in patients with Gleason scores ≥ 7 when compared to patients with Gleason scores < 7(p = 0.002). Among the 26 cases of TGF-β1 overexpression, 92.3% had poor prognostic features.

CONCLUSIONS

TGF-β1 was underexpressed in prostate cancers; however, higher expression was observed in tumors with higher Gleason scores, which suggests that TGF-β1 expression may be a useful prognostic marker for prostate cancer. Further studies of clinical specimens are needed to clarify the role of TGF-β1 in prostate carcinogenesis.

Loss of function of e-cadherin in embryonic stem cells and the relevance to models of tumorigenesis

E-cadherin is the primary cell adhesion molecule within the epithelium, and loss of this protein is associated with a more aggressive tumour phenotype and poorer patient prognosis in many cancers. Loss of E-cadherin is a defining characteristic of epithelial-mesenchymal transition (EMT), a process associated with tumour cell metastasis. We have previously demonstrated an EMT event during embryonic stem (ES) cell differentiation, and that loss of E-cadherin in these cells results in altered growth factor response and changes in cell surface localisation of promigratory molecules. We discuss the implication of loss of E-cadherin in ES cells within the context of cancer stem cells and current models of tumorigenesis. We propose that aberrant E-cadherin expression is a critical contributing factor to neoplasia and the early stages of tumorigenesis in the absence of EMT by altering growth factor response of the cells, resulting in increased proliferation, decreased apoptosis, and acquisition of a stem cell-like phenotype.

Transcription alterations of members of the ubiquitin-proteasome network in prostate carcinoma

The purpose of this work was to investigate the role of the ubiquitin-proteasome network (UPN) in prostate cancer (PCA) and to elicit potential markers for this disease. The UPN represents a key factor in the maintenance of cellular homoeostasis as a result of its fundamental function in the regulation of intracellular protein degradation. Members of this network have a role in the biology of haematological and solid tumours. Tumour cells and normal epithelial cells from 22 prostatectomy specimens were isolated by laser microdissection. Prostate biopsy samples from healthy individuals served for technical calibration and as controls. Transcript levels of eight selected genes with E3 ubiquitin ligase activity (labelling target proteins for proteasome degradation) and two genes belonging to the proteasome-multienzyme complex itself were analysed by quantitative real-time RT-PCR. The proteasome genes PSMC4 and PSMB5 and the E3 ubiquitin ligase NEDD4L were significantly and coherently upregulated in PCA cells compared with the corresponding adjacent normal prostate tissue. Transcription of the E3 ubiquitin ligase SMURF2 was significantly higher in organ-confined tumours (pT2) compared with non-organ-confined cancers (pT3). The results indicate a role for PSMC4 and PSMB5 and the E3 ubiquitin ligase NEDD4L in prostate tumourigenesis, whereas SMURF2 downregulation could be associated with clinical progression. NEDD4L and SMURF2 both target transforming growth factor (TGF)-β for degradation. This reflects the pleiotropic role of the TGF-β signalling pathway acting as a tumour suppressor in normal and pre-cancerous cells, but having oncogenic properties in progressing cancer. Further studies have to elucidate whether these alterations could represent clinically relevant PCA-diagnostic and progression markers.

Overexpression of transforming growth factor β1 in malignant prostate cells is partly caused by a runaway of TGF-β1 auto-induction mediated through a defective recruitment of protein phosphatase 2A by TGF-β type I receptor

OBJECTIVES

To elucidate the mechanism of transforming growth factor (TGF)-β1 overexpression in prostate cancer cells.

METHODS

Malignant (PC3, DU145) and benign (RWPE1, BPH1) prostate epithelial cells were used. Phosphatase activity was measured using a commercial kit. Recruitment of the regulatory subunit, Bα, of protein phosphatase 2A (PP2A-Bα) by TGF-β type I receptor (TβRI) was monitored by coimmunoprecipitation. Blockade of TGF-β1 signaling in cells was accomplished either by using TGF-β-neutralizing monoclonal antibody or by transduction of a dominant negative TGF-β type II receptor retroviral vector.

RESULTS

Basal levels of TGF-β1 in malignant cells were significantly higher than those in benign cells. Blockade of TGF-β signaling resulted in a significant decrease in TGF-β1 expression in malignant cells, but not in benign cells. Upon TGF-β1 treatment (10 ng/mL), TGF-β1 expression was increased in malignant cells, but not in benign cells. This differential TGF-β1 auto-induction between benign and malignant cells correlated with differential activation of extracellular signal-regulated kinase (ERK). Following TGF-β1 treatment, the activity of serine/threonine phosphatase and recruitment of PP2A-Bα by TβRI increased in benign cells, but not in malignant cells. Inhibition of PP2A in benign cells resulted in an increase in ERK activation and in TGF-β1 auto-induction after TGF-β1 (10 ng/mL) treatment.

CONCLUSIONS

These results suggest that TGF-β1 overexpression in malignant cells is caused, at least in part, by a runaway of TGF-β1 auto-induction through ERK activation because of a defective recruitment of PP2A-Bα by TβRI.

Transforming growth factor beta1 mediates apoptotic activity of angiotensin II type I receptor blocker on prostate epithelium in vitro

BACKGROUND

The significant association of benign prostatic hyperplasia (BPH) and hypertension indicates a common pathophysiological factor for both diseases. Hyperactivity of the renin-angiotensin system (RAS) has been reported in BPH. Angiotensin II type I (AT1) receptor is the principal mediator of the RAS, and the antagonist, AT1 receptor blocker (ARB), can induce apoptosis in prostate epithelium cells and increase transforming growth factor beta1 (TGF-beta1) expression. We aimed to investigate the mechanism of inhibition of AT1 receptor in prostate epithelium cells and the role of TGF-beta1.

METHODS

Human prostate epithelium cell lines were treated with different concentrations of ARB (losartan) (0, 0.1, 1, 10, 100, and 1,000 microM) for 24-72 hr. Cell proliferation was analyzed by cell proliferation assay. The location of AT1 receptor was shown by immunocytohistochemistry and immunocytofluorescence study. Analysis of apoptosis was by use of terminal transferase TdT-mediated dUTP-biotin end labeling (TUNEL) and caspase 3/7 activity assay. Mitochondrial outer-membrane permeabilization was measured by JC-1 staining. The level of TGF-beta1 was determined by enzyme-linked immunosorbent assay.

RESULTS

Immunohistochemistry and immunofluorescence analysis showed AT1 receptor expressed in epithelium cells. Compared to control cultures, cultures treated with losartan for 24-72 hr showed a dose-dependent significant decrease in cell number, with apoptosis increased by 65.2%. Decreased cell number was reversed on treatment with anti-TGF-beta1 antibody. TUNEL staining showed increased apoptosis in prostate epithelium cells exposed to losartan. Caspase 3/7 activation was increased and mitochondrial membrane potential was downregulated. Expression of TGF-beta1 in cells treated with losartan was higher than that in untreated cells.

CONCLUSIONS

The apoptotic effect of blockade of AT1 receptor on human prostatic epithelium cells may be mediated through an autocrine the production of TGF-beta1. Furthermore, this finding may have implications for medication options. Inc.

Potential role of multiple members of the kallikrein-related peptidase family of serine proteases in activating latent TGF beta 1 in semen

Transforming growth factor beta1 (TGF beta 1) has been implicated as a key contributor of immunosuppression in seminal plasma. The biochemical mechanisms that lead to production of active seminal TGF beta 1 are not fully understood. It is plausible that TGF beta 1 activation is partly induced simultaneously with the release of motile spermatozoa following liquefaction of the semen coagulum. Several members of the kallikrein-related peptidase (KLK) family are involved in the regulation of semen liquefaction. This study examines the involvement of these KLKs in TGF beta 1 activation in vitro and ex vivo, in seminal plasma. Latent TGF beta 1 was rapidly activated by KLK14. The latency-associated propeptide (LAP) was shown to be cleaved by KLK14 into small peptide fragments, providing a possible mechanism for TGF beta 1 activation. KLK14 also cleaved the latent TGFbeta binding protein 1 (LTBP1). KLK1, 2, and 5 might also contribute to TGF beta 1 activation by nicking the LAP motif and inducing conformational changes that aid in subsequent processing of LAP or through LTBP1 cleavage. Our study provides strong evidence for the involvement of multiple members of the seminal KLK cascade in activation of latent TGF beta 1 in seminal plasma. These findings might have clinical implications in infertility treatment of cases with concurrent delayed liquefaction and TGF beta 1-related semen antigenicity.

Both nongenomic and genomic effects are involved in estradiol's enhancing the phenotype of smooth muscle cells in cultured prostate stromal cells

BACKGROUND

Stromal smooth muscle cells (SMCs) play an important role in the pathogenesis and clinical symptom of benign prostatic hyperplasia. We had reported that estrogen enhances the phenotype of SMC in cultured prostate stromal cells (PRSCs). Here we further investigate the mechanism by which estrogen affects the differentiation of PRSCs.

METHODS

Primary cultured PRSCs were stimulated with E2 or BSA-E2. The mRNA level of SMC-specific genes, smoothelin, and SM-MHC were measured by qRT-PCR. The SM-MHC protein was measured by Western blot. The mRNA and protein levels of TGF-beta1 were measured by qRT-PCR and ELISA. The MAPK inhibitor PD98059, the estrogen receptor antagonist ICI182,780 and neutralizing antibody to TGF-beta1 were used to reveal the mechanism of estrogen effect.

RESULTS

E2 and BSA-E2 significantly up-regulate the expression of SMC-specific genes in PRSCs. Both forms of estrogen could increase the expression of TGF-beta1, which can be blocked by pre-treating with PD98059. Moreover, PD98059 and TGF-beta1 neutralizing antibody could abrogate the effect of BSA-E2 on cell differentiation. However, they could only inhibit part of E2-induced SMC phenotype enhancement. ICI182,780 could partially suppress the pro-differentiation effect of E2 but had no influence on the effect of BSA-E2. Combined treatment with ICI182,780 and PD98059 can completely abrogate the effect of E2.

CONCLUSIONS

Estrogen could promote the expression of TGF-beta1 in PRSCs through nongenomic activation of MAPK pathway, and in turn enhance the SMC phenotype. Besides for this nongenomic effect, estrogen can also enhance the SMC phenotype through classical genomic action.

Role of the renin-angiotensin system in prostate cancer

Prostate cancer is highly prevalent in Western society, and its early stages can be controlled by androgen ablation therapy. However, the cancer eventually regresses to an androgen-independent state for which there is no effective treatment. The renin-angiotensin system (RAS), in particular the octapeptide angiotensin II, is now recognised to have important effects on growth factor signalling and cell growth in addition to its well known actions on blood pressure, fluid homeostasis and electrolyte balance. All components of the RAS have been recently identified in the prostate, consistent with the expression of a local RAS system in this tissue. This review focuses on the role of the RAS in the prostate, and the possibility that this pathway may be a potential therapeutic target for the treatment of prostate cancer and other prostatic diseases.

Regulation of growth factors in hormone- and drug-resistant prostate cancer cells by synergistic combination of docetaxel and octreotide

OBJECTIVE To evaluate the effects of combined treatment with docetaxel and octreotide, a somatostatin analogue, on human hormone- and drug-refractory prostate cancer cell lines, PC-3 and DU-145, and on some growth factors related to tumour growth and angiogenesis in prostate cancer. MATERIALS AND METHODS A cell proliferation assay was used to assess the cytotoxicity of the drugs. To verify apoptosis, both DNA fragmentation (by enzyme-linked immunosorbent assay) and caspase 3/7 activity were measured. We also investigated the effect of combined docetaxel and octreotide on growth factors secreted from prostate cancer cells using a human growth factor antibody array. RESULTS The combination of docetaxel and octreotide resulted in significant synergistic cytotoxic activity and apoptosis, which was dose- and time-dependent. The combined treatment also resulted in significantly less secretion of stem cell factor and platelet-derived growth factor-AB in PC-3 cells, and transforming growth factor-beta and basic fibroblast growth factor in DU-145 cells, than in untreated controls. CONCLUSION Octreotide, a somatostatin analogue, combined with docetaxel might provide a rationale treatment option for hormone-refractory prostate cancer cells, not only by direct inhibition of cell proliferation but also by inhibiting the secretion of growth factors.

Transforming growth factor-beta-mediated signaling in T lymphocytes impacts on prostate-specific immunity and early prostate tumor progression

T cells are in general tolerant of prostate-specific tumor antigens. That prostate tumor tissue makes transforming growth factor-beta (TGFbeta) is thought to play a role in the induction of T-cell tolerance within the host and to contribute to tumor progression itself. Here we sought to investigate the influence of TGFbeta signaling on prostate antigen-specific T-cell responses as well as prostate tumorogenesis in an autochthonous murine model of the disease. The response of naive and activated ovalbumin (OVA) antigen-specific T cells, which had been rendered incapable of responding to TGFbeta through T-cell-specific transgenic expression of a dominant-negative variant of the TGFbeta receptor II (dnTGFRII), was analyzed after adoptive transfer into prostate OVA-expressing transgenic (POET) mice. The role of TGFbeta signaling in endogenous T cells in mice, which spontaneously form tumors, was also assessed by monitoring prostate tumor formation and progression in F1 progeny of productive matings between transgenic adenocarcinoma of the mouse prostate (TRAMP) and dnTGFRII mice. TGFbeta-resistant CD8(+) T cells proliferated more and produced IFNgamma more readily after OVA stimulation in vitro. OVA-specific T cells did not damage the prostate gland of POET mice irrespective of TGFbeta responsiveness. However, ex vivo activation facilitated entry of TGFbeta-insensitive T cells into the prostate and was associated with prostate tissue damage. Early tumor progression was delayed in TRAMP mice that carried endogenous TGFbeta-insensitive T cells. Together, these results suggest that TGFbeta-signaling represses CD8(+) T-cell responses to a prostate-specific antigen. TGFbeta-mediated repression of T-cell function may include production of IFNgamma, which is known to contribute to tumor immunosurveillance.

Oxidative stress-related aging: A role for prostate cancer?

Prostate cancer has the highest prevalence of any non-cutaneous cancer in the human body and essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. Aging, considered as an impairment of body functions over time, caused by the accumulation of molecular damage in DNA, proteins and lipids, is also characterized by an increase in intracellular oxidative stress due to the progressive decrease of the intracellular ROS scavenging. The aging damage may eventually appear in age-related health issues, which have a significant impact on the independence, general well-being and morbidity of the elderly. The association of aging with prostate cancer is undisputable as well as the association of aging with oxidative stress. Nevertheless, supportive evidence linking an increase in oxidative stress with prostate cancer is still scarce. This review is a comprehensive, literature-based analysis of the association of human prostate cancer with oxidative stress. The objective was to examine the involvement of reactive oxygen species in the mechanisms of prostatic carcinogenesis since the understanding of risk factors for prostate cancer has practical importance for public health, genetic and nutritional education, and chemoprevention.

Regulation of TGF-beta1 gene transcription in human prostate cancer cells by nitric oxide

BACKGROUND

Overexpression of transforming growth factor (TGF)-beta1 is associated with advanced prostate cancer. Our previous studies showed an inverse correlation between the expressions of TGF-beta1 and inducible nitric oxide synthase (iNOS) in prostatic tumors in mice. The purpose of this study was to investigate regulation of TGF-beta1 expression in human prostate cancer cells by nitric oxide (NO).

METHODS

Expression of TGF-beta1 in the three well-characterized lines of human prostate cancer cells (PC-3MM2, LNCaP, and DU145) was determined by using the enzyme-linked immunoabsorbance assay (ELISA), real-time reverse-transcriptase PCR (RT-PCR), nuclear run-on, and promoter activity analyses.

RESULTS

Expression of both TGF-beta1 protein and mRNA was inhibited in both dose- and time-dependent manners by NO donors sodium nitroprusside (SNP), S-nitroso-N-acetylpenicilamine (SNAP), S-nitrosoglutathione (GSNO), and (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexeneamide (NOR-1) and by transfection of iNOS. The inhibitory effects of SNP and iNOS on TGF-beta1 expression were reduced in cells treated with NO scavengers N-dithiocarboxysarcosine (DTCS), 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), and hemoglobin, or with the iNOS inhibitor N-methyl-arginine (NMA). SNP downregulated the in vitro transcription of TGF-beta1 mRNA, inhibited TGF-beta1 promoter activity, but had no significant effects on TGF-beta1 mRNA stability.

CONCLUSION

These results show that NO downregulates TGF-beta1 expression in prostate cancer cells at transcription level by suppressing the de novo synthesis of TGF-beta1 mRNA.

Prohibitin and cofilin are intracellular effectors of transforming growth factor beta signaling in human prostate cancer cells

A proteomic analysis was pursued to identify new signaling effectors of transforming growth factor beta1 (TGF-beta1) that serve as potential intracellular effectors of its apoptotic action in human prostate cancer cells. The androgen-sensitive and TGF-beta-responsive human prostate cancer cells, LNCaP T beta RII, were used as in vitro model. In response to TGF-beta, significant posttranslational changes in two proteins temporally preceded apoptotic cell death. TGF-beta mediated the nuclear export of prohibitin, a protein involved in androgen-regulated prostate growth, to the cytosol in the LNCaP T beta RII cells. Cofilin, a protein involved in actin depolymerization, cell motility, and apoptosis, was found to undergo mitochondrial translocation in response to TGF-beta before cytochrome c release. Loss-of-function approaches (small interfering RNA) to silence prohibitin expression revealed a modest decrease in the apoptotic response to TGF-beta and a significant suppression in TGF-beta-induced cell migration. Silencing Smad4 showed that the cellular localization changes associated with prohibitin and cofilin action in response to TGF-beta are independent of Smad4 intracellular signaling.

Transforming growth factor-beta promotes invasion in tumorigenic but not in nontumorigenic human prostatic epithelial cells

Transforming growth factor-beta (TGF-beta) is a pleiotropic growth factor with actions that are dependent on circumstances, including dose, target cell type, and context. TGF-beta can elicit both growth-promoting and growth-suppressive activities. In normal tissues, TGF-beta generally acts to restrict growth and maintain differentiation. However, during tumorigenesis, changes in TGF-beta expression and cellular responses can promote tumorigenesis. The present study examines the effects of TGF-beta on the nontumorigenic human prostatic epithelial cell line BPH1 and on three derivative tumorigenic sublines BPH1(CAFTD)1, BPH1(CAFTD)3, and BPH1(CAFTD)5. The data show that TGF-beta has different effects on the nontumorigenic and tumorigenic cells. The nontumorigenic cells are growth inhibited by TGF-beta. In contrast, the tumorigenic sublines are not growth inhibited but instead undergo an epithelial to mesenchymal transformation (EMT) in response to TGF-beta. The tumorigenic lines show constitutively elevated levels of phosphorylated Akt, which modulates their response to TGF-beta by blocking Smad3 and p21 nuclear translocation. On TGF-beta stimulation of the tumorigenic sublines, the activated Akt allows the cell to escape cell cycle arrest. The phosphatidylinositol 3-kinase/Akt pathway is also involved in TGF-beta-induced EMT, defined here by induction of vimentin expression and enhanced cellular motility. In vivo, tumorigenic cells with constitutively active TGF-beta signaling show increased invasion with EMT, which express vimentin, located specifically at the invasive front of the tumor. These data indicate that following malignant transformation TGF-beta can play a direct role in promoting prostatic cancer and further that these responses are context specific in vivo.

Culture requirements of prostatic epithelial cell lines for acinar morphogenesis and lumen formation in vitro: role of extracellular calcium

BACKGROUND

Three-dimensional (3D) culture of benign prostatic epithelial cell lines can recapitulate acinar morphogenesis in vitro, but the broad applicability of this approach has not been described. The present studies examine the culture conditions important for prostatic acinar morphogenesis in vitro and the role of extracellular calcium in this process.

METHODS

With optimized culture conditions, RWPE-1, pRNS-1-1, PZ-HPV-7, PNT1A, BPH-1, and PrEC were analyzed for their ability to undergo acinar morphogenesis in 3D culture and by immunoblotting. RWPE-1 cells were further examined for the effects of calcium on morphology, E-cadherin membrane localization and multicellular layering in 2D culture and for acinar morphogenesis, luminal apoptosis, and luminal filling in 3D.

RESULTS

Cell lines grown in low-calcium medium have the ability to form acinar structures with lumens, which correlates with E-cadherin expression, but low calcium is not required for this process. Adding CaCl(2) to the medium strongly inhibits lumen formation, luminal apoptosis and induces luminal filling, and luminal filling is blocked by an interfering antibody.

CONCLUSIONS

Optimized medium composition allows nearly all seeded RWPE-1 cells to undergo acinar morphogenesis, forming consistent structures representative of normal adult prostate glands. Low-calcium-containing medium appears selective for cells capable of undergoing acinar morphogenesis in vitro, and branching and luminal space within the acini are strongly influenced by extracellular calcium levels, likely through the actions of E-cadherin. These results provide important information about a relevant in vitro model with which to study prostate development and carcinogenesis and highlight the importance of extracellular calcium in regulating 3D morphology.

Effect of castration on extracellular matrix remodeling and angiogenesis of the prostate gland

This study was conducted to evaluate the long term effect of castration on the prostate gland proliferation, extracellular matrix remodeling and angiogenesis. Prostate gland proliferation was assessed by immunolocalization of proliferating cell nuclear antigen (PCNA). The expression level of vascular endothelial growth factor (VEGF), transforming growth factor-beta (TGF-beta) and metaloprotenase-13 (MMP-13) by the prostate gland were assessed by immunohistochemistry and quantitative real-time PCR. The expression of the above mentioned parameters by the prostate gland of mature intact dogs were compared to that of castrated dogs six months post-castration. The results showed that castration induced a remarkable atrophy of the prostate gland which was associated with a highly significant decrease in the PCNA proliferation index. Although TGF-beta protein was immunolocalized to the epithelial and stroma cells of the prostate gland from both intact and castrated dogs, castration induced a significant up-regulation of TGF-beta mRNA expression. VEGF mRNA expression and its encoded protein immunolocalization were decreased significantly by the prostate gland from castrated dogs as compared to that of intact dogs. Castration, on the other hand, resulted in no significant change in MMP-13 mRNA expression despite an effect on its cellular immunolocalization which appeared to be localized to the epithelial and stromal cells of the prostate gland from castrated dogs as compared to epithelial cells of the prostate gland from intact dogs. These results indicated that castration-induced prostate gland regression continued to exert a potent suppressive effect on prostate gland proliferation which might be mediated by the elevated level of TGF-beta. Moreover, the low expression level of VEGF might reflect a reduced blood flow demand by the regressed and growth-dormant prostate after castration.

Vaccination therapy in prostate cancer

Radical prostatectomy and radiation therapy provide excellent localized prostate cancer (PC) control. Although the majority of prostate carcinoma is nowadays diagnosed at early stages with favourable risk features, in patients up to 30-40% it recurs within 10 years. Furthermore, the lack of effective therapies, once prostate carcinoma becomes refractory to androgen deprivation, mandates the development of alternative therapeutic options. There is a growing interest in harnessing the potency and specificity of anti-tumour immunity through the generation of fully competent dendritic cells and tumour reactive effector lymphocytes. Several strategies to treat or prevent the development of metastatic PC have been explored in clinical trials and are summarized in this review, considering also the feasibility and safety of these approaches. In some cases clinical responses were achieved showing that vaccine-primed T cells induced anti-tumour activity in vivo. The present findings and perspectives of the immunologic interventions in PC patients will be discussed.