PSMA-targeted combination brusatol and docetaxel nanotherapeutics for the treatment of prostate cancer.

Active targeting to cancer involves exploiting specific interactions between receptors on the surface of cancer cells and targeting moieties conjugated to the surface of vectors such that site-specific delivery is achieved. Prostate specific membrane antigen (PSMA) has proved to be an excellent target for active targeting to prostate cancer. We report the synthesis and use of a PSMA-specific ligand (Glu-NH-CO-NH-Lys) for the site-specific delivery of brusatol- and docetaxel-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles to prostate cancer. The PSMA targeting ligand covalently linked to PLGA-PEG3400 was blended with methoxyPEG-PLGA to prepare brusatol- and docetaxel-loaded nanoparticles with different surface densities of the targeting ligand. Flow cytometry was used to evaluate the impact of different surface densities of the PSMA targeting ligand in LNCaP prostate cancer cells at 15 min and 2 h. Cytotoxicity evaluations of the targeted nanoparticles reveal differences based on PSMA expression in PC-3 and LNCaP cells. In addition, levels of reactive oxygen species (ROS) were measured using the fluorescent indicator, H2DCFDA, by flow cytometry. PSMA-targeted nanoparticles loaded with docetaxel and brusatol showed increased ROS generation in LNCaP cells compared to PC-3 at different time points. Furthermore, the targeted nanoparticles were evaluated in male athymic BALB/c mice implanted with PSMA-producing LNCaP cell tumors. Evaluation of the percent relative tumor volume show that brusatol-containing nanoparticles show great promise in inhibiting tumor growth. Our data also suggest that the dual drug-loaded targeted nanoparticle platform improves the efficacy of docetaxel in male athymic BALB/c mice implanted with PSMA-producing LNCaP cell tumors.

Preparation, Optimization, and In-Vitro Evaluation of Brusatol- and Docetaxel-Loaded Nanoparticles for the Treatment of Prostate Cancer.

Challenges to docetaxel use in prostate cancer treatment include several resistance mechanisms as well as toxicity. To overcome these challenges and to improve the therapeutic efficacy in heterogeneous prostate cancer, the use of multiple agents that can destroy different subpopulations of the tumor is required. Brusatol, a multitarget inhibitor, has been shown to exhibit potent anticancer activity and play an important role in drug response and chemoresistance. Thus, the combination of brusatol and docetaxel in a nanoparticle platform for the treatment of prostate cancer is expected to produce synergistic effects. In this study, we reported the development of polymeric nanoparticles for the delivery of brusatol and docetaxel in the treatment of prostate cancer. The one-factor-at-a-time method was used to screen for formulation and process variables that impacted particle size. Subsequently, factors that had modifiable effects on particle size were evaluated using a 24 full factorial statistical experimental design followed by the optimization of drug loading. The optimization of blank nanoparticles gave a formulation with a mean size of 169.1 nm ± 4.8 nm, in agreement with the predicted size of 168.333 nm. Transmission electron microscopy showed smooth spherical nanoparticles. The drug release profile showed that the encapsulated drugs were released over 24 h. Combination index data showed a synergistic interaction between the drugs. Cell cycle analysis and the evaluation of caspase activity showed differences in PC-3 and LNCaP prostate cancer cell responses to the agents. Additionally, immunoblots showed differences in survivin expression in LNCaP cells after treatment with the different agents and formulations for 24 h and 72 h. Therefore, the nanoparticles are potentially suitable for the treatment of advanced prostate cancer.

The International Fragile X Premutation Registry: building a resource for research and clinical trial readiness.

FMR1 premutation cytosine-guanine-guanine repeat expansion alleles are relatively common mutations in the general population that are associated with a neurodegenerative disease (fragile X-associated tremor/ataxia syndrome), reproductive health problems and potentially a wide range of additional mental and general health conditions that are not yet well-characterised. The International Fragile X Premutation Registry (IFXPR) was developed to facilitate and encourage research to better understand the FMR1 premutation and its impact on human health, to facilitate clinical trial readiness by identifying and characterising diverse cohorts of individuals interested in study participation, and to build community and collaboration among carriers, family members, researchers and clinicians around the world. Here, we describe the development and content of the IFXPR, characterise its first 747 registrants from 32 countries and invite investigators to apply for recruitment support for their project(s). With larger numbers, increased diversity and potentially the future clinical characterisation of registrants, the IFXPR will contribute to a more comprehensive and accurate understanding of the fragile X premutation in human health and support treatment studies.

Corrigendum to "Annexin 2 protein expression is associated with breast cancer subtypes in African American women" [Heliyon Volume 6, Issue 2, February 2020, e03241].

[This corrects the article DOI: 10.1016/j.heliyon.2020.e03241.].

Annexin 2 protein expression is associated with breast cancer subtypes in African American women.

BACKGROUND: A review of literature on the expression of Annexin 2 in cancer has shown that there is very limited research work on the association of this protein with breast cancer aggressiveness in African Americans. In the present study, TMA breast tissues from African American women were stained with Annexin 2 antibody to determine the association between the molecular subtypes and Annexin 2 protein expression. METHOD: An annotated case series of 135 breast cancer tissues archived from 2000 to 2010 was acquired from the Howard University Tumor Registry. The association between ANX2 expression and survival by molecular subtypes Luminal A, Luminal B, HER2, and Triple Negative (TN) was assessed using Multinomial regression, chi-square analysis, and Kaplan-Meir graphs (Stata 11). RESULTS: Our findings show a marked association between ANX2 protein expression in Luminal B and HER2 subtypes unadjusted and when adjusted for age. Borderline differences in tumor grade were found in TN only.Univariately, age (<50, 50 + years) and metastases were highly significant for overall survival, disease-free survival and recurrence-free survival. Stage, tumor size, and nodal involvement were of borderline or greater significance for overall and disease-free survival. ANX2 expression was not significant. Kaplan Meier tests of ANX2 showed significant separation of overall survival by ANX2 protein expression in all breast tumor subtypes. In multivariate analyses comparing TN to Luminal A, ANX2 was not important while controlling for age and grade. CONCLUSION: ANX2 might be a biomarker of aggressiveness and a relevant candidate biomarker in high risk African American women with Luminal B and HER2 breast cancer.

Microarray and pathway analysis of two COMMA-Dß derived clones reveal important differences relevant to their developmental capacity in-vivo.

Microarray technologies were used to analyze transcriptomes from Comma-Dß and clonal derivatives, SP3 (Lobule-competent) and NSP2 (Lobule-incompetent), during different mouse mammary growth phases: in-vitro, in-vivo 5-weeks, and in-vivo 12-weeks. A differentially expressed gene (DEG) algorithm was used to enrich for genes associated with cellular proliferation, differentiation, cell cycle regulation, and carcinogenesis. A pairwise comparison analysis, of SP3 vs. NSP2 in-vitro, revealed a total of 45 DEGs significantly up-regulated in SP3. Of the 45 DEGs, only Ccnd1 (Cyclin D1), Id2 (Inhibitor of DNA binding 2) and Sox9 (SRY Box 9) were identified to be associated with cellular proliferation, regulation of G1/S mitotic cell cycle, mammary gland and alveolar development in SP3. During the regenerative growth phase, in-vivo 5-weeks, we identified a total of 545 DEGs. 308 DEGs, of the 545 DEGs, were significantly up-regulated and 237 DEGs were significantly down-regulated in SP3 vs. NSP2. In addition, we identified 9 DEGs significantly up-regulated, within SP3's cell cycle pathway and a persistent overexpression of Cyclin D1, Id2, and Sox9, consistent with our in-vitro study. During the maintenance phase, in-vivo 12-weeks, we identified 407 DEGs. Of these, 336 DEGs were up-regulated, and 71 were down-regulated in SP3 vs. NSP2. Our data shows 15 DEGs significantly up-regulated, simultaneously, affecting 8 signal transducing carcinogenic pathways. In conclusion, increased expression of Cyclin D1, Id2 and Sox9 appear to be important for lobular genesis in SP3. Also, in-vivo 12 week displays increase expression of genes and pathways, involved in tumorigenesis.

CCAAT-displacement protein/cut homeobox transcription factor (CUX1) represses estrogen receptor-alpha (ER-α) in triple-negative breast cancer cells and can be antagonized by muscadine grape skin extract (MSKE).

Triple-Negative Breast Cancers (TNBCs) are the most difficult to treat subtype of breast cancer and are often associated with high nuclear expression of Snail and Cathepsin L (Cat L) protease. We have previously shown that Snail can increase Cat L expression/activity in prostate and breast cancer cells. This study investigated the role of CUX1 (a downstream substrate of Cat L) in TNBC. We showed that Cat L and CUX1 were highly expressed in TNBC patient tissue/cell lines, as compared to ER-positive samples, using cBioportal data and western blot/zymography analyses. Additionally, luciferase reporter and chromatin immunoprecipitation assays showed that CUX1 directly bound to estrogen receptor-alpha (ER-α) promoter in MDA-MB-468, a representative TNBC cell line, and that CUX1 siRNA could restore ER-α transcription and protein expression. Furthermore, Snail and CUX1 expression in various TNBC cell lines was inhibited by muscadine grape skin extract (MSKE, a natural grape product rich in anthocyanins) or Cat L inhibitor (Z-FY-CHO) leading to decreased cell invasion and migration. MSKE decreased cell viability and increased expression of apoptotic markers in MDA-MB-468 cells, with no effect on non-tumorigenic MCF10A cells. MSKE also decreased CUX1 binding to ER-α promoter and restored ER-α expression in TNBC cells, while both MSKE and CUX1 siRNA restored sensitivity to estradiol and 4-hydoxytamoxifen as shown by increased cell viability. Therefore, CUX1 activated by Snail-Cat L signaling may contribute to TNBC via ER-α repression, and may be a viable target for TNBC using natural products such as MSKE that targets cancer and not normal cells.

Muscadine grape skin extract inhibits prostate cancer cells by inducing cell-cycle arrest, and decreasing migration through heat shock protein 40.

Previously we demonstrated that muscadine grape skin extract (MSKE), a natural product, significantly inhibited androgen-responsive prostate cancer cell growth by inducing apoptosis through the targeting of survival pathways. However, the therapeutic effect of MSKE on more aggressive androgen-independent prostate cancer remains unknown. This study examined the effects of MSKE treatment in metastatic prostate cancer using complementary PC-3 cells and xenograft model. MSKE significantly inhibited PC-3 human prostate cancer cell tumor growth in vitro and in vivo. The growth-inhibitory effect of MSKE appeared to be through the induction of cell-cycle arrest. This induction was accompanied by a reduction in the protein expression of Hsp40 and cell-cycle regulation proteins, cyclin D1 and NF-kBp65. In addition, MSKE induced p21 expression independent of wild-type p53 induced protein expression. Moreover, we demonstrate that MSKE significantly inhibited cell migration in PC-3 prostate cancer cells. Overall, these results demonstrate that MSKE inhibits prostate tumor growth and migration, and induces cell-cycle arrest by targeting Hsp40 and proteins involved in cell-cycle regulation and proliferation. This suggests that MSKE may also be explored either as a neo-adjuvant or therapeutic for castration resistant prostate cancer.

Sex differences in the use of healthcare services among US adults with and without a cancer diagnosis.

OBJECTIVE: Cancer imposes higher burden on men. Sex differences in healthcare utilization may contribute to this problem. We compared healthcare utilization among adults with and without a history of cancer as measured by having at least one physician visit within the previous 12 months. MATERIAL AND METHODS: We analyzed data from 7,229 responders (weighted population size=211,722,892) enrolled in the 2007 Health Information and National Trends Survey (HINTS), a nationally representative sample of non-institutionalized adults in the United States. We used survey weights in all analyses and variance estimation procedures to account for the complex survey design and used logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Study participants consisted of 2808 (48.6%) males and 4421 (51.4%) females. Overall, men were less likely to have seen a physician within the previous 12 months (OR=0.39; 95% CI: 0.31-0.48) regardless of their cancer status. Cancer survivors were more likely to visit a physician within the previous 12 months (OR=2.01; 95% CI: 1.28-3.19) regardless of sex. When stratified by personal history of cancer, men without a history of cancer were less likely to visit a physician (OR=0.38; 95% CI: 0.30-0.47) whereas men with a history of cancer were as likely to have seen a physician in the previous 12 months as women with similar cancer status (OR=1.24; 95% CI: 0.44-3.45). CONCLUSION: Men increase their healthcare utilization to that of women only after they receive diagnosis of cancer. Targeted interventions to promote utilization of preventive care services by men are needed to reduce the burden of chronic illnesses including cancer among men.

Protective Effects of Donepezil Against Alcohol-Induced Toxicity in Cell Culture: Role of Caspase-3.

Ethanol (EtOH) is one of the most frequently abused drugs with heavy health, economic, and societal burdens. Although moderate to low EtOH may have some neuroprotective effects, heavy EtOH consumption associated with high blood alcohol level (BAL) can be quite detrimental. The brain is particularly vulnerable to the damaging effects of high BAL, leading to neuronal loss, cognitive, and behavioral deficits. Although the exact causes of these detriments are not fully elucidated, it is believed that damage to the cholinergic system is at least partially responsible for the cognitive impairment. Thus, high BAL may result in selective apoptotic damage to the cholinergic neurons. Donepezil (DON), a centrally acting, reversible and non-competitive acetylcholinesterase (AChE) inhibitor, approved for use in Alzheimer's disease (AD), may also attenuate EtOH-induced cognitive impairment. Cognitive effects of DON might be due to an anti-apoptotic activity as some AChE inhibitors have been shown to have this property. The aim of this study was to determine whether DON might protect against EtOH-induced toxicity and whether such protection might be apoptotically mediated. We exposed the human neuroblastoma-derived, SH-SY5Y cells to a relatively high concentration of EtOH (500 mM) for 24 h and evaluated the effects of two concentrations of DON (0.1 and 1.0 µM) on alcohol-induced toxicity and caspase-3, an apoptotic marker. We found a dose-dependent protection of DON against EtOH-induced toxicity as well as dose-dependent attenuation of EtOH-induced increases in caspase-3 levels. Thus, DON may inhibit apoptosis as well as alcohol-induced toxicity.

Differential expression of Annexin 2, SPINK1, and Hsp60 predict progression of prostate cancer through bifurcated WHO Gleason score categories in African American men.

BACKGROUND: Although studies have observed several markers correlate with progression of prostate cancer (PCa), no specific markers have been identified that accurately predict the progression of this disease, even in African American (AA) men who are generally at higher risk than other ethnic groups. The primary goal of this study was to explore whether three markers could predict the progression of PCa. METHOD: We investigated protein expression of Annexin 2 (ANX2), serine peptidase inhibitor, kazal type 1(SPINK1)/tumor-associated trypsin inhibitor (TATI), and heat shock protein 60 (Hsp60) in 79 archival human prostate trans-rectal ultrasound (TRUS) biopsy tissues according to a modified World Health Organization (WHO) classification: normal (WHO1a), Gleason Score (GS6 (WHO1b), GS7 subgroups (WHO2 = 3 + 4, WHO3 = 4 + 3), GS8 (WHO4), and GS9-10 (WHO5). AA men aged 41-90 diagnosed from 1990 to 2013 at Howard University were included. Automated staining assessed expression of each biomarker. Spearman correlation assessed the direction and relationship between biomarkers, WHO and modified WHO GS, age, and 5-year survival. A two-tailed t-test and ANOVA evaluated biomarkers expression in relationship to WHO normal and other GS levels, and between WHO GS levels. A logistic and linear regression analysis examined the relationship between biomarker score and WHO GS categories. Kaplan-Meier curves graphed survival. RESULTS: ANX2 expression decreased monotonically with the progression of PCa while expression of SPINK1/TATI and Hsp60 increased but had a more WHO GS-specific effect; SPINK1/TATI differed between normal and GS 2-6 and HSP60 differed between GS 7 and GS 2-6. WHO GS was found to be significantly and negatively associated with ANX2, and positively with SPINK1/TATI and Hsp60 expression. High SPINK1/TATI expression together with the low ANX2 expression at higher GS exhibited a bi-directional relationship that is associated with PCa progression and survival. CONCLUSION: Importantly, the data reveal that ANX2, and SPINK1/TAT1 highly associate with WHO GS and with the transition from one stage of PrCa to the next in AA men. Future research is needed in biracial and larger population studies to confirm this dynamic relationship between ANX2 and SPINK1 as independent predictors of PCa progression in all men.

Muscadine Grape Skin Extract (MPX) in Men with Biochemically Recurrent Prostate Cancer: A Randomized, Multicenter, Placebo-Controlled Clinical Trial.

Purpose: MuscadinePlus (MPX), a commercial preparation of pulverized muscadine grape skin, was evaluated as a therapeutic option for men with biochemically recurrent (BCR) prostate cancer wishing to defer androgen deprivation therapy.Experimental Design: This was a 12-month, multicenter, placebo-controlled, two-dose, double-blinded trial of MPX in 125 men with BCR prostate cancer, powered to detect a PSA doubling time (PSADT) difference of 6 months (low dose) and 12 months (high dose) relative to placebo. Participants were stratified (baseline PSADT, Gleason score) and randomly assigned 1:2:2 to receive placebo, 500 mg MPX (low), or 4,000 mg MPX (high) daily. Correlates included superoxide dismutase-2 (SOD2) genotype, lipid peroxidation, and polyphenol pharmacokinetics.Results: The evaluable population included 112 patients, all treated for at least 6 months and 62% treated for 12 months. No significant difference was found in PSADT change between control and treatment arms (P = 0.81): control 0.9 months (n = 20; range, 6.7-83.1), low dose 1.5 months (n = 52; range, 10.3-87.2), high dose 0.9 months (n = 40; range, 27.3-88.1). One high-dose patient experienced objective response. No drug-related CTCAE grade 3-4 adverse events were seen. In a preplanned exploratory analysis, PSADT pre-to-post increase was significant in the 27 (26%) genotyped patients with SOD2 Alanine/Alanine genotype (rs4880 T>C polymorphism) on MPX (pooled treatment arms; 6.4 months, P = 0.02), but not in control (1.8 months, P = 0.25).Conclusions: Compared with placebo, MPX did not significantly prolong PSADT in BCR patients over two different doses. Exploratory analysis revealed a patient population with potential benefit that would require further study. Clin Cancer Res; 24(2); 306-15. ©2017 AACR.

Muscadine Grape Skin Extract Induces an Unfolded Protein Response-Mediated Autophagy in Prostate Cancer Cells: A TMT-Based Quantitative Proteomic Analysis.

Muscadine grape skin extract (MSKE) is derived from muscadine grape (Vitis rotundifolia), a common red grape used to produce red wine. Endoplasmic reticulum (ER) stress activates the unfolded protein response (UPR) that serves as a survival mechanism to relieve ER stress and restore ER homeostasis. However, when persistent, ER stress can alter the cytoprotective functions of the UPR to promote autophagy and cell death. Although MSKE has been documented to induce apoptosis, it has not been linked to ER stress/UPR/autophagy. We hypothesized that MSKE may induce a severe ER stress response-mediated autophagy leading to apoptosis. As a model, we treated C4-2 prostate cancer cells with MSKE and performed a quantitative Tandem Mass Tag Isobaric Labeling proteomic analysis. ER stress response, autophagy and apoptosis were analyzed by western blot, acridine orange and TUNEL/Annexin V staining, respectively. Quantitative proteomics analysis indicated that ER stress response proteins, such as GRP78 were greatly elevated following treatment with MSKE. The up-regulation of pro-apoptotic markers PARP, caspase-12, cleaved caspase-3, -7, BAX and down-regulation of anti-apoptotic marker BCL2 was confirmed by Western blot analysis and apoptosis was visualized by increased TUNEL/Annexin V staining upon MSKE treatment. Moreover, increased acridine orange, and LC3B staining was detected in MSKE-treated cells, suggesting an ER stress/autophagy response. Finally, MSKE-mediated autophagy and apoptosis was antagonized by co-treatment with chloroquine, an autophagy inhibitor. Our results indicate that MSKE can elicit an UPR that can eventually lead to apoptosis in prostate cancer cells.

Muscadine grape skin extract can antagonize Snail-cathepsin L-mediated invasion, migration and osteoclastogenesis in prostate and breast cancer cells.

To develop new and effective chemopreventive agents against bone metastasis, we assessed the effects of muscadine grape skin extract (MSKE), whose main bioactive component is anthocyanin, on bone turnover, using prostate and breast cancer cell models overexpressing Snail transcription factor. MSKE has been shown previously to promote apoptosis in prostate cancer cells without affecting normal prostate epithelial cells. Snail is overexpressed in prostate and breast cancer, and is associated with increased invasion, migration and bone turnover/osteoclastogenesis. Cathepsin L (CatL) is a cysteine cathepsin protease that is overexpressed in cancer and involved in bone turnover. Snail overexpression in prostate (LNCaP, ARCaP-E) and breast (MCF-7) cancer cells led to increased CatL expression/activity and phosphorylated STAT-3 (pSTAT-3), compared to Neo vector controls, while the reverse was observed in C4-2 (the aggressive subline of LNCaP) cells with Snail knockdown. Moreover, CatL expression was higher in prostate and breast tumor tissue compared to normal tissue. MSKE decreased Snail and pSTAT3 expression, and abrogated Snail-mediated CatL activity, migration and invasion. Additionally, Snail overexpression promoted osteoclastogenesis, which was significantly inhibited by the MSKE as effectively as Z-FY-CHO, a CatL-specific inhibitor, or osteoprotegerin, a receptor activator of nuclear factor kappa B ligand (RANKL) antagonist. Overall, these novel findings suggest that Snail regulation of CatL may occur via STAT-3 signaling and can be antagonized by MSKE, leading to decreased cell invasion, migration and bone turnover. Therefore, inhibition using a natural product such as MSKE could potentially be a promising bioactive compound for bone metastatic cancer.

A phase I study of muscadine grape skin extract in men with biochemically recurrent prostate cancer: Safety, tolerability, and dose determination.

BACKGROUND: New therapies are being explored as therapeutic options for men with biochemically recurrent prostate cancer (BRPC) who wish to defer androgen deprivation therapy. MPX is pulverized muscadine grape (Vitis rotundifolia) skin that contains ellagic acid, quercetin, and resveratrol and demonstrates preclinical activity against prostate cancer cells in vitro. METHODS: In the phase I portion of this phase I/II study, non-metastatic BRPC patients were assigned to increasing doses of MPX (Muscadine Naturals. Inc., Clemmons, NC) in cohorts of two patients, with six patients at the highest dose, using a modified continual reassessment method. Initial dose selection was based on preclinical data showing the equivalent of 500 to 4,000 mg of MPX to be safe in mouse models. The primary endpoint was the recommended phase II dosing regimen. RESULTS: The cohort (n = 14, 71% Caucasian, 29% black) had a median follow-up of 19.2 (6.2-29.7) months, median age of 61 years, and median Gleason score of 7. Four patients had possibly related gastrointestinal symptoms, including grade 1 flatulence, grade 1 soft stools, and grade 1 eructation. No other related adverse events were reported and one patient reported improvement of chronic constipation. Six of 14 patients came off study for disease progression (five metastatic, one rising PSA) after exposure for a median of 15 months. One patient came off for myasthenia gravis that was unrelated to treatment. Seven patients remain on study. The lack of dose-limiting toxicities led to the selection of 4,000 mg/d as the highest dose for further study. Median within-patient PSADT increased by 5.3 months (non-significant, P = 0.17). No patients experienced a maintained decline in serum PSA from baseline. CONCLUSION: These data suggest that 4,000 mg of MPX is safe, and exploratory review of a lengthening in PSADT of a median of 5.3 months supports further exploration of MPX. Both low-dose (500 mg) and high-dose (4,000 mg) MPX are being further investigated in a randomized, multicenter, placebo-controlled, dose-evaluating phase II trial.

Muscadine grape skin extract reverts snail-mediated epithelial mesenchymal transition via superoxide species in human prostate cancer cells.

BACKGROUND: Snail transcription factor can induce epithelial-mesenchymal transition (EMT), associated with decreased cell adhesion-associated molecules like E-cadherin, increased mesenchymal markers like vimentin, leading to increased motility, invasion and metastasis. Muscadine grape skin extract (MSKE) has been shown to inhibit prostate cancer cell growth and induce apoptosis without affecting normal prostate epithelial cells. We investigated novel molecular mechanisms by which Snail promotes EMT in prostate cancer cells via Reactive Oxygen Species (ROS) and whether it can be antagonized by MSKE. METHODS: ARCaP and LNCaP cells overexpressing Snail were utilized to examine levels of reactive oxygen species (ROS), specifically, superoxide, in vitro using Dihydroethidium (DHE) or HydroCy3 dyes. Mitosox staining was performed to determine whether the source of ROS was mitochondrial in origin. We also investigated the effect of Muscadine grape skin extract (MSKE) on EMT marker expression by western blot analysis. Migration and cell viability using MTS proliferation assay was performed following MSKE treatments. RESULTS: Snail overexpression in ARCaP and LNCaP cells was associated with increased concentration of mitochondrial superoxide, in vitro. Interestingly, MSKE decreased superoxide levels in ARCaP and LNCaP cells. Additionally, MSKE and Superoxide Dismutase (SOD) reverted EMT as evidenced by decreased vimentin levels and re-induction of E-cadherin expression in ARCaP-Snail cells after 3 days, concomitant with reduced cell migration. MSKE also decreased Stat-3 activity in ARCaP-Snail cells. CONCLUSIONS: This study shows that superoxide species may play a role in Snail transcription factor-mediated EMT. Therefore, therapeutic targeting of Snail with various antioxidants such as MSKE may prove beneficial in abrogating EMT and ROS-mediated tumor progression in human prostate cancer.

Selenoproteins reduce susceptibility to DMBA-induced mammary carcinogenesis.

Selenium is an essential micronutrient in the diet of humans and other mammals. Based largely on animal studies and epidemiological evidence, selenium is purported to be a promising cancer chemopreventive agent. However, the biological mechanisms by which chemopreventive activity takes place are poorly understood. It remains unclear whether selenium acts in its elemental form, through incorporation into organic compounds, through selenoproteins or any combination of these. The purpose of this study was to determine whether selenoproteins mitigate the risk of developing chemically induced mammary cancer. Selenoprotein expression was ablated in mouse mammary epithelial cells through genetic deletion of the selenocysteine (Sec) tRNA gene (Trsp), whose product, designated selenocysteine tRNA, is required for selenoprotein translation. Trsp floxed and mouse mammary tumor virus (MMTV)-cre mice were crossed to achieve tissue-specific excision of Trsp in targeted mammary glands. Eight- to twelve-week-old second generation Trsp(fl/+);wt, Trsp(fl/+);MMTV-cre, Trsp(fl/fl);wt and Trsp(fl/fl);MMTV-cre female mice were administered standard doses of the carcinogen, 7,12-dimethylbenzylbenz[a]antracene. Our results revealed that heterozygous, Trsp(fl/+);MMTV-cre mice showed no difference in tumor incidence, tumor rate and survival compared with the Trsp(fl/+);wt mice. However, 54.8% of homozygous Trsp(fl/f)(l);MMTV-cre mice developed mammary tumors and exhibited significantly shorter survival than the corresponding Trsp(fl/fl);wt mice, where only 36.4% developed tumors. Loss of the homozygous Trsp alleles was associated with the reduction of selenoprotein expression. The results suggest that mice with reduced selenoprotein expression have increased susceptibility to developing carcinogen-induced mammary tumors and that a major protective mechanism against carcinogen-induced mammary cancer requires the expression of these selenoproteins.

Inhibition of androgen-responsive LNCaP prostate cancer cell tumor xenograft growth by dietary phenethyl isothiocyanate correlates with decreased angiogenesis and inhibition of cell attachment.

Phenethyl isothiocyanate (PEITC) is a candidate anticancer compound found in certain cruciferous vegetables. In our tumor cell xenograft model, dietary administration of PEITC (100-150 mg/kg body weight/d) inhibited androgen-responsive LNCaP human prostate cancer cell tumor growth. We found that dietary treatment with PEITC significantly inhibited tumor platelet/endothelial cell adhesion molecule (PECAM-1/CD31) expression, a marker of angiogenesis. By contrast, we did not find the inhibitory effects of PEITC on tumor growth to be associated with alteration of specific markers for apoptosis, cell proliferation or androgen receptor-mediated pathways. Consistent with in vivo results, PEITC exerted little effects on cell proliferation, cell cycle and androgen-dependent pathways. Interestingly, PEITC significantly attenuated LNCaP cell plating efficiency that correlated with inhibition of integrin family proteins integrin ß1, α2 and α6 mRNA expression. Thus, PEITC may be a dietary factor that inhibits androgen-responsive prostate tumor growth indirectly by selectively targeting factors involved in the tumor microenvironment.

Peroxisome Proliferator-Activated Receptor-α Activation Decreases Mean Arterial Pressure, Plasma Interleukin-6, and COX-2 While Increasing Renal CYP4A Expression in an Acute Model of DOCA-Salt Hypertension.

Peroxisome proliferator-activated receptor-alpha (PPAR-α) activation by fenofibrate reduces blood pressure and sodium retention during DOCA-salt hypertension. PPAR-α activation reduces the expression of inflammatory cytokines, such as interleukin-6 (IL-6). Fenofibrate also induces cytochrome P450 4A (CYP4A) and increases 20-hydroxyeicosatetraenoic acid (20-HETE) production. This study tested whether the administration of fenofibrate would reduce blood pressure by attenuating plasma IL-6 and renal expression of cyclooxygenase-2 (COX-2), while increasing expression of renal CYP4A during 7 days of DOCA-salt hypertension. We performed uni-nephrectomy on 12-14 week old male Swiss Webster mice and implanted biotelemetry devices in control, DOCA-salt (1.5 mg/g) treated mice with or without fenofibrate (500 mg/kg/day in corn oil, intragastrically). Fenofibrate significantly decreased mean arterial pressure and plasma IL-6. In kidney homogenates, fenofibrate increased CYP4A and decreased COX-2 expression. There were no differences in renal cytochrome P450, family 2, subfamily c, polypeptide 23 (CYP2C23) and soluble expoxide hydrolase (sEH) expression between the groups. Our results suggest that the blood pressure lowering effect of PPAR-α activation by fenofibrate involves the reduction of plasma IL-6 and COX-2, while increasing CYP4A expression during DOCA-salt hypertension. Our results may also suggest that PPAR-α activation protects the kidney against renal injury via decreased COX-2 expression.

Differential effects of resveratrol on androgen-responsive LNCaP human prostate cancer cells in vitro and in vivo.

Resveratrol is a phytochemical that has been under consideration for use as a prostate cancer chemopreventive agent. However, the efficacy, as well as the mechanisms of action of resveratrol on prostate cancer prevention, remains largely unknown. This study seeks to address these questions and examine the cancer preventive effects of resveratrol using complementary human LNCaP prostate cancer cell culture and xenograft models. In cultured LNCaP cells, we found that resveratrol inhibited cell growth. The growth inhibitory effects of resveratrol appeared to be through modulation of both androgen- and estrogen-mediated events. Global gene expression analysis using microarrays identified androgen-responsive genes as a group of genes universally affected by resveratrol in LNCaP cells in vitro. The effect of resveratrol on expression of these genes appeared to be through inhibition of both androgen- and estrogen-mediated transcription. In a xenograft model, resveratrol delayed LNCaP tumor growth and inhibited expression of a marker for steroid hormone responses. However, exposure to resveratrol also led to increased angiogenesis and inhibition of apoptosis in the xenograft. In summary, resveratrol may act through modulation of steroid hormone-dependent pathways to inhibit prostate cancer cell growth in both culture and xenografts, but exposure in vivo may be of concern.