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Simple Summary: Disparity in clinical outcome data due to the biological heterogeneity of prostate cancer (PCa) has drawn attention to approaches that stratify homogeneous subsets of patients. In recent years, PCa fusion genes (specifically TMPRSS2-ERG fusion) have been identified as oncogenic drivers with the potential for patient stratification and as targets for effective prevention/intervention strategies in drug efficacy trials. In the present study, employing relevant TMPRSS2-ERG (fusion)-driven and non-TMPRSS2-ERG-driven mouse models of PCa, we report the potential usefulness of the non-steroidal anti-inflammatory drugs (NSAIDs) aspirin and naproxen specifically against TMPSS2-ERG fusion-driven prostate tumorigenesis. These findings are consistent with the clinical observations and warrant further investigation of the molecular mechanisms and utility of NSAID interventions for precision cancer prevention. The consumption of the non-steroidal anti-inflammatory drug (NSAID) aspirin is associated with a significant reduction in the risk of developing TMPRSS2-ERG (fusion)-positive prostate cancer (PCa) compared to fusion-negative PCa in population-based case–control studies; however, no extensive preclinical studies have been conducted to investigate and confirm these protective benefits. Thus, the focus of this study was to determine the potential usefulness of aspirin and another NSAID, naproxen, in PCa prevention, employing preclinical models of both TMPRSS2-ERG (fusion)-driven (with conditional deletion of Pten) and non-TMPRSS2-ERG-driven (Hi-Myc+/− mice) PCa. Male mice (n = 25 mice/group) were fed aspirin- (700 and 1400 ppm) and naproxen- (200 and 400 ppm) supplemented diets from (a) 6 weeks until 32 weeks of Hi-Myc+/− mice age; and (b) 1 week until 20 weeks post-Cre induction in the fusion model. In all NSAID-fed groups, compared to no-drug controls, there was a significant decrease in higher-grade adenocarcinoma incidence in the TMPRSS2-ERG (fusion)-driven PCa model. Notably, there were no moderately differentiated (MD) adenocarcinomas in the dorsolateral prostate of naproxen groups, and its incidence also decreased by ~79–91% in the aspirin cohorts. In contrast, NSAIDs showed little protective effect against prostate tumorigenesis in Hi-Myc+/− mice, suggesting that NSAIDs exert a specific protective effect against TMPRSS2-ERG (fusion)-driven PCa. [ABSTRACT FROM AUTHOR]

Simple Summary: The stage of a tumor during cancer intervention is the most crucial factor that determines the treatment regimen. Several bioactive natural compounds have shown potential to inhibit prostate cancer growth and progression; however, there is a dearth of studies that explore their efficacy at different stages of tumorigenesis. This knowledge gap prevents researchers from fully exploiting the anti-cancer potential of these beneficial compounds. Accordingly, our present study focused on explicating the 'stage-specific' efficacy of the bioactive food component 'inositol hexaphosphate (IP6, phytic acid)' against PCa initiation, growth, and progression in the transgenic adenocarcinoma of the mouse prostate TRAMP model. Results indicated that IP6 feeding during initial stages of cancer development prevents progression of prostatic intraepithelial neoplasia lesions to adenocarcinoma, and IP6 feeding during late stage of the disease reduces tumor growth and prevents its progression to advanced stage of the disease. Thus, IP6 intervention is beneficial during all stages of prostate tumorigenesis. Herein, we assessed the stage-specific efficacy of inositol hexaphosphate (IP6, phytic acid), a bioactive food component, on prostate cancer (PCa) growth and progression in a transgenic mouse model of prostate cancer (TRAMP). Starting at 4, 12, 20, and 30 weeks of age, male TRAMP mice were fed either regular drinking water or 2% IP6 in water for ~8–15 weeks. Pathological assessments at study endpoint indicated that tumor grade is arrested at earlier stages by IP6 treatment; IP6 also prevented progression to more advanced forms of the disease (~55–70% decrease in moderately and poorly differentiated adenocarcinoma incidence was observed in advanced stage TRAMP cohorts). Next, we determined whether the protective effects of IP6 are mediated via its effect on the expansion of the cancer stem cells (CSCs) pool; results indicated that the anti-PCa effects of IP6 are associated with its potential to eradicate the PCa CSC pool in TRAMP prostate tumors. Furthermore, in vitro assays corroborated the above findings as IP6 decreased the % of floating PC-3 prostaspheres (self-renewal of CSCs) by ~90%. Together, these findings suggest the multifaceted chemopreventive-translational potential of IP6 intervention in suppressing the growth and progression of PCa and controlling this malignancy at an early stage. [ABSTRACT FROM AUTHOR]

African American men face a stark prostate cancer (PCa)‐related health disparity, with the highest incidence and mortality rates compared to other races. Additional and innovative measures are warranted to reduce this health disparity. Here, we focused on the identification of a novel serum exosome‐based "protein signature" for potential use in the early detection and better prognosis of PCa in African American men. Nanoparticle tracking analyses showed that compared to healthy individuals, exosome concentration (number/ml) was increased by ~3.2‐fold (P ˂ 0.05) in the sera of African American men with PCa. Mass spectrometry‐based proteomic analysis of serum exosomes identified seven unique and fifty‐five overlapping proteins (up‐ or downregulated) in African Americans with PCa compared to healthy African Americans. Furthermore, ingenuity pathway analyses identified the inflammatory acute‐phase response signaling as the top pathway associated with proteins loaded in exosomes from African American PCa patients. Interestingly, African American PCa E006AA‐hT cells secreted exosomes strongly induced a proinflammatory M2‐phenotype in macrophages and showed calcium response on sensory neurons, suggesting a neuroinflammatory response. Additionally, proteomic analyses showed that the protein Isoform 2 of Filamin A has higher loading (2.6‐fold) in exosomes from African Americans with PCa, but a lesser loading (0.6‐fold) was observed in exosomes from Caucasian men with PCa compared to race‐matched healthy individuals. Interestingly, TCGA and Taylor's dataset as well as IHC analyses of PCa tissue showed a lower Filamin A expression in tissues of PCa patients compared with normal subjects. Overall, these results support the usefulness of serum exosomes to noninvasively detect inflammatory phenotype and to discover novel biomarkers associated with PCa in African American men. In this work, we characterized the proteins loaded in exosomes isolated from the serum of African American prostate cancer patients and identified a novel protein signature. [ABSTRACT FROM AUTHOR]

New silibinin phosphodiester glyco-conjugates were synthesized by efficient phosphoramidite chemistry and were fully characterized by 2D-NMR. A wide-ranging study focused on the determination of their pKa and E ° values as well as on their radical scavenging activities by different assays (DPPH, ABTS + and HRSA) was conducted. The new glyco-conjugates are more water-soluble than silibinin, and their radical scavenging activities are higher than those of silibinin. The conjugation therefore improves both the water solubilities and antioxidant activities of the flavonolignan moieties. The serum stability was evaluated under physiological conditions, and the glyco-conjugates degraded with half-lives of 40–70 h, making them useful in pro-drug approaches. We started by treating androgen-dependent prostate cancer (PCa) LNCaP cells and then expanded our studies to androgen-independent PCa PC3 and DU145 cells. In most cases, the new derivatives significantly reduced both total and live cell numbers, albeit at different levels. Anti-HIV activities were evaluated and the glucosamine-phosphate silibinin derivative showed higher activity (IC 50  = 73 μM) than silibinin. [ABSTRACT FROM AUTHOR]

Background A better molecular understanding of prostate carcinogenesis is warranted to devise novel targeted preventive and therapeutic strategies against prostate cancer (PCA), a major cause of mortality among men. Here, we examined the role of two epithelial-to-mesenchymal transition (EMT) regulators, the adherens junction protein E-cadherin and its transcriptional repressor SNAI1, in regulating the aggressiveness of PCA cells. Methods The growth rate of human prostate carcinoma PC3 cells with stable knock-down of Ecadherin (ShEC-PC3) and respective control cells (Sh-PC3) was compared in MTT and clonogenic assays in cell culture and in nude mouse xenograft model in vivo. Stemness of ShEC-PC3 and Sh-PC3 cells was analyzed in prostasphere assay. Western blotting and immunohistochemistry (IHC) were used to study protein expression changes following Ecadherin and SNAI1 knock-down. Small interfering RNA (siRNA) technique was employed to knock- down SNAI1 protein expression in ShEC-PC3 cells. Results ShEC-PC3 cells exerted higher proliferation rate both in cell culture and in athymic nude mice compared to Sh-PC3 cells. ShEC-PC3 cells also formed larger and a significantly higher number of prostaspheres suggesting an increase in the stem cell-like population with Ecadherin knock-down. Also, ShEC-PC3 prostaspheres disintegration, in the presence of serum and attachment, generated a bigger mass of proliferating cells as compared to Sh-PC3 prostaspheres. Immunoblotting/IHC analyses showed that E-cadherin knock-down increases the expression of regulators/biomarkers for stemness (CD44, cleaved Notch1 and Egr-1) and EMT (Vimentin, pSrc-tyr416, Integrin β3, β-catenin, and NF-κB) in cell culture and xenograft tissues. The expression of several bone metastasis related molecules namely CXCR4, uPA, RANKL and RunX2 was also increased in ShEC-PC3 cells. Importantly, we observed a remarkable increase in SNAI1 expression in cytoplasmic and nuclear fractions, prostaspheres and xenograft tissues of ShEC-PC3 cells. Furthermore, SNAI1 knock-down by specific siRNA strongly inhibited the prostasphere formation, clonogenicity and invasiveness, and decreased the level of pSrc-tyr416, total Src and CD44 in ShEC-PC3 cells. Characterization of RWPE-1, WPE1-NA22, WPE1-NB14 and DU-145 cells further confirmed that low E-cadherin is associated with higher SNAI1 expression and prostasphere formation. Conclusions Together, these results suggest that E-cadherin loss promotes SNAI1 expression that controls the aggressiveness of PCA cells. [ABSTRACT FROM AUTHOR]

The role of neo-angiogenesis in prostate cancer (PCA) growth and metastasis is well established, but the development of effective and non-toxic pharmacological inhibitors of angiogenesis remains an unaccomplished goal. In this regard, targeting aberrant angiogenesis through non-toxic phytochemicals could be an attractive angiopreventive strategy against PCA. The rationale of the present study was to compare the anti-angiogenic potential of four pure diastereoisomeric flavonolignans, namely silybin A, silybin B, isosilybin A and isosilybin B, which we established previously as biologically active constituents in Milk Thistle extract. Results showed that oral feeding of these flavonolignans (50 and 100 mg/kg body weight) effectively inhibit the growth of advanced human PCA DU145 xenografts. Immunohistochemical analyses revealed that these flavonolignans inhibit tumor angiogenesis biomarkers (CD31 and nestin) and signaling molecules regulating angiogenesis (VEGF, VEGFR1, VEGFR2, phospho-Akt and HIF-1α) without adversely affecting the vessel-count in normal tissues (liver, lung, and kidney) of tumor bearing mice. These flavonolignans also inhibited the microvessel sprouting from mouse dorsal aortas ex vivo, and the VEGF-induced cell proliferation, capillary-like tube formation and invasiveness of human umbilical vein endothelial cells (HUVEC) in vitro. Further studies in HUVEC showed that these diastereoisomers target cell cycle, apoptosis and VEGF-induced signaling cascade. Three dimensional growth assay as well as co-culture invasion and in vitro angiogenesis studies (with HUVEC and DU145 cells) suggested the differential effectiveness of the diastereoisomers toward PCA and endothelial cells. Overall, these studies elucidated the comparative anti-angiogenic efficacy of pure flavonolignans from Milk Thistle and suggest their usefulness in PCA angioprevention. [ABSTRACT FROM AUTHOR]

Purpose: The 3,3″-di-O-galloyl ester of procyanidin B2 (B2G2) is a component of grape seed extract that inhibits growth of human prostate carcinoma cell lines. In preparation for studies in mice, its hepatic metabolism was examined in vitro and compared to B2 and the corresponding monomers, epicatechin (EC) and 3-O-galloyl-epicatechin (ECG). Methods: Compounds were incubated with liver microsomes or cytosol containing cofactors for glucuronidation, sulfation or methylation, and products analyzed by liquid chromatography-mass spectrometry (LC-MS). B2G2 was administered orally to mice and plasma analyzed by LC-MS for unmodified procyanidin and metabolites. Results: Glucuronides and methyl ethers of B2 and B2G2 were formed in small amounts. In contrast, EC and ECG were largely or completely converted to glucuronides, sulfates and methyl ethers under the same incubation conditions. B2G2 given orally to mice was partially absorbed intact; no significant metabolites were detected in plasma. Conclusions: Glucuronidation and methylation of procyanidins B2 and B2G2 occurred but were minor processes in vitro. B2G2 was partially absorbed intact in mice after oral dosing and did not undergo significant metabolism. Unlike the flavanol monomers EC and ECG, therefore, B2G2 bioavailability should not be limited by metabolism. These results paved the way for ongoing pharmacokinetic and efficacy studies. [ABSTRACT FROM AUTHOR]

Present study assessed the influence of gallate esterification on the anti-cancer activity of procyanidin B2 (B2) in androgen-dependent human prostate carcinoma LNCaP cells employing B2-3,3′-di-O-gallate (B2-G2), two mono-gallate esters B2-3-O-gallate (B2-3G) and B2-3′-O-gallate (B2-3′G) and the parent compound B2, all isolated from grape seed extract (GSE). Study compounds were isolated from GSE by several chromatographic steps and structures determined by a combination of enzymatic hydrolysis, mass spectrometry and comparisons with standards. Cells, treated with these compounds, were assessed for viability and apoptosis and examined by western blotting. Gallate esters B2-G2, B2-3G and B2-3′G significantly decreased LNCaP cell viability; however, B2 and gallic acid were ineffective. Furthermore, only B2-G2 also significantly decreased cell growth. Decreases in cell viability were largely due to apoptosis induction with B2-G2 and B2-3′G exhibiting comparable effects, whereas B2-3G was less effective. In mechanistic studies, B2-G2 and B2-3′G treatments caused caspases-9 and -3 and PARP cleavage, and down-regulated Bcl-2, Bcl-Xl and androgen receptor levels. Together, our findings demonstrate anti-PCA efficacy of B2-G2 and suggest that a gallate ester moiety at 3′ position of procyanidin B2 contributes more extensively toward the biological activity of the di-gallate ester than esterification of position 3. [ABSTRACT FROM AUTHOR]

Prostate cancer (PCA) is the most common invasive malignancy and the second leading cause of cancer-related deaths in the US male population. One approach to control this malignancy is its preventive intervention by dietary agents. Inositol hexaphosphate (IP6), a dietary constituent, has shown promising efficacy against various cancers; however, limited studies have been performed with IP6 against PCA. Here, we investigated the growth-inhibitory effect and associated mechanisms of IP6 in androgen-dependent human prostate carcinoma LNCaP cells. IP6 treatment of cells resulted in a strong growth inhibition and an increase in G1 cell population. In mechanistic studies, IP6 resulted in an increase in cyclin-dependent kinase inhibitors (CDKIs) Cip1/p21 and Kip1/p27 levels, together with a decrease in cyclin-dependent kinase (CDK) 4 and cyclin D1 protein levels. An increase in CDKI levels by IP6 also led to a concomitant increase in their interactions with CDK2 and CDK4, together with a strong decrease in the kinase activity of both CDKs. Downstream in CDKI-CDK-cyclin cascade, consistent with its inhibitory effect on CDK kinase activity, IP6 treatment of cells increased hypophosphorylated levels of retinoblastoma (Rb) with a decrease in Rb phosphorylation at serine 780, 807, and 811 sites, and caused a moderate to strong decrease in the levels of transcription factors E2F1, E2F4, and E2F5. In other studies, IP6 caused a dose- and a time-dependent apoptotic death of LNCaP cells, and a decrease in BcI2 levels, causing a strong increase in Bax versus BcI2 ratio, as well as an inhibition of constitutively active AKT phosphorylation. Taken together, these molecular alterations provide an insight into IP6-caused growth inhibition, G1 arrest, and apoptotic death of human prostate carcinoma LNCaP cells. Because early clinical PCA growth is an androgen-dependent response, the results of the present study employing androgen-dependent LNCaP cells suggest that IP6 has promise and... [ABSTRACT FROM AUTHOR]

Abstract: Prostate cancer (PCA) is the most commonly diagnosed cancer in men in the United States with growing worldwide incidence. Despite intensive investment in improving early detection, PCA often escapes timely detection and mortality remains high; this malignancy being the second highest cancer-associated mortality in American men. Collectively, health care costs of PCA results in an immense financial burden that is only expected to grow. Additionally, even in cases of successful treatment, PCA is associated with long-term and pervasive effects on patients. A proactive alternative to treat PCA is to prevent its occurrence and progression prior to symptomatic malignancy. This may serve to address the issue of burgeoning healthcare costs and increasing number of sufferers. One potential regimen in service of this alternative is PCA chemoprevention. Here, chemical compounds with cancer preventive efficacy are identified on the basis of their potential in a host of categories: their historical medicinal use, correlation with reduced risk in population studies, non-toxicity, their unique chemical properties, or their role in biological systems. PCA chemopreventive agents are drawn from multiple broad classes of chemicals, themselves further subdivided based on source or potential effect, with most derived from natural products. Many such compounds have shown efficacy, varying from inhibiting deregulated PCA cell signaling, proliferation, epithelial to mesenchymal transition (EMT), invasion, metastasis, tumor growth and angiogenesis and inducing apoptosis. Overall, these chemopreventive agents show great promise in PCA pre-clinical models, though additional work remains to be done in effectively translating these findings into clinical use. [Copyright &y& Elsevier]

Prostate cancer (PCA) is the 2nd leading cause of cancer-related deaths among men in the United States. Preventing or inhibiting metastasis-related events through non-toxic agents could be a useful approach for lowering high mortality among PCA patients. We have earlier reported that natural flavonoid silibinin possesses strong anti-metastatic efficacy against PCA however, mechanism/s of its action still remains largely unknown. One of the major events during metastasis is the replacement of cell–cell interaction with integrins-based cell–matrix interaction that controls motility, invasiveness and survival of cancer cells. Accordingly, here we examined silibinin effect on advanced human PCA PC3 cells’ interaction with extracellular matrix component fibronectin. Silibinin (50–200 μM) treatment significantly decreased the fibronectin (5 μg/ml)-induced motile morphology via targeting actin cytoskeleton organization in PC3 cells. Silibinin also decreased the fibronectin-induced cell proliferation and motility but significantly increased cell death in PC3 cells. Silibinin also inhibited the PC3 cells invasiveness in Transwell invasion assays with fibronectin or cancer associated fibroblasts (CAFs) serving as chemoattractant. Importantly, PC3-luc cells cultured on fibronectin showed rapid dissemination and localized in lungs following tail vein injection in athymic male nude mice; however, in silibinin-treated PC3-luc cells, dissemination and lung localization was largely compromised. Molecular analyses revealed that silibinin treatment modulated the fibronectin-induced expression of integrins (α5, αV, β1 and β3), actin-remodeling (FAK, Src, GTPases, ARP2 and cortactin), apoptosis (cPARP and cleaved caspase 3), EMT (E-cadherin and β-catenin), and cell survival (survivin and Akt) related signaling molecules in PC3 cells. Furthermore, PC3-xenograft tissue analyses confirmed the inhibitory effect of silibinin on fibronectin and integrins expression. Together, these results showed that silibinin targets PCA cells’ interaction with fibronectin and inhibits their motility, invasiveness and survival; thus further supporting silibinin use in PCA intervention including its metastatic progression. [ABSTRACT FROM AUTHOR]

[Display omitted] Curcumin is a bioactive natural compound with a wide range of pharmacological properties, including antitumor activity; however, its clinical application has been limited because of its low solubility, stability, and bioavailability. In this study, a solid phase approach was proposed for the combinatorial synthesis of a mini library of the mimics of curcumin in good purity and yield. The non-effective findings in pancreatic cancer cells switched to strong growth inhibition and cell death efficacy for PC3 prostate cancer cells, and mimic 9 , in which tyrosol (TYR) and homovanillyl alcohol (HVA) units were linked by a phosphodiester bond, was quite effective not only in cell growth inhibition but also in causing strong cell death under the study conditions and treatments that were not effective in PANC1 cells. The results got more exciting when we also consider the findings in SW480 human colorectal carcinoma cell line, where the growth inhibitor effects were more in line with that of the PC3 cells, but the lack of cell death effect was more in line with the PANC1 cells. [ABSTRACT FROM AUTHOR]