Suppression of prostate carcinogenesis by dietary supplementation of celecoxib in transgenic adenocarcinoma of the mouse prostate model

Differential effects of jaboticaba peel extract administration on PCa progression in TRAMP mice depend on the androgenic status of the prostatic milieu and are driven by angiogenesis regulation

Jaboticaba peel extract (JPE) has demonstrated chemopreventive effects on the development of prostatic lesions in experimental systems, including the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP). However, its influence over castration-resistant prostate cancer (CRPC) and the androgenic dependence of its actions in this model remain unknown. Therefore, we aimed to evaluate JPE effects on TRAMP mice tumorigenesis under different androgen reliance settings. Mice were submitted to short- or long-term JPE administration, associated or not with androgen deprivation therapy (ADT) by surgical and chemical castration. Prostate, periaortic lymph nodes and lung samples were harvested to determine the incidence of primary and metastatic lesions. Protein expression of proliferative, hormonal and angiogenesis markers was evaluated. Results showed that JPE administration in a hormone naive setting restricted poorly-differentiated tumors to the ventral prostate. Additionally, treatment extension improved the proportion of tumor-free individuals and the timeline for the development of palpable tumors. These results were paralleled by significant increment on VE-Cadherin expression. Furthermore, JPE-treated groups demonstrated significantly lower incidences of lymphatic metastasis. Conversely, JPE plus ADT resulted in poor outcomes, especially upon the extension of this association. In this setting, decreased survival, lower tumor-free mice proportion and increment of proliferative epithelial areas were registered. Altogether, such effects were attributed to a time-dependent up- (VEGF, latent TGF-β2 and TGFβ-RI) or downregulation (VEGFR-2 and VE-Cadherin) of angiogenic mediators expression. Therefore, we conclude that long-term ADT in TRAMP mice drives the prostatic microenvironment dynamics towards a proangiogenic state, which negatively impacts or even abolishes the otherwise beneficial effects of JPE.

The Potential Preventive and Therapeutic Roles of NSAIDs in Prostate Cancer

Prostate cancer (PC) is the second most common type of cancer and the leading cause of death among men worldwide. Preventing the progression of cancer after treatments such as radical prostatectomy, radiation therapy, and hormone therapy is a major concern faced by prostate cancer patients. Inflammation, which can be caused by various factors such as infections, the microbiome, obesity and a high-fat diet, is considered to be the main cause of PC. Inflammatory cells are believed to play a crucial role in tumor progression. Therefore, nonsteroidal anti-inflammatory drugs along with their effects on the treatment of inflammation-related diseases, can prevent cancer and its progression by suppressing various inflammatory pathways. Recent evidence shows that nonsteroidal anti-inflammatory drugs are effective in the prevention and treatment of prostate cancer. In this review, we discuss the different pathways through which these drugs exert their potential preventive and therapeutic effects on prostate cancer.

Lobe-specific responses of TRAMP mice dorsolateral prostate following celecoxib and nintedanib therapy

Delayed cancer progression in the ventral prostate of the Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP) model has been previously reported upon celecoxib and nintedanib co-administration. Herein, we sought to further investigate the effects of these drugs association in some of their direct molecular targets (COX-2, VEGF and VEGFR-2) and in reactive stroma markers (TGF-β, αSMA, vimentin and pro-collagen 1) in the dorsolateral prostate, looking for lobe-specific responses. Male TRAMP mice were treated with celecoxib (10 mg/Kg, i.o.) and/or nintedanib (15 mg/Kg, i.o.) for 6 weeks and prostate was harvested for morphological and protein expression analyses. Results showed that combined therapy resulted in unique antitumor effects in dorsolateral prostate, especially due to the respective stromal or epithelial antiproliferative actions of these drugs, which altogether led to a complete inversion in high-grade (HGPIN) versus low-grade (LGPIN) premalignant lesion incidences in relation to controls. At the molecular level, this duality in drug action was paralleled by the differential down/upregulation of TGF-β signaling by celecoxib/nintedanib, thus leading to associated changes in stroma composition towards regression or quiescence, respectively. Additionally, combined therapy was able to promote decreased expression of inflammatory (COX-2) and angiogenesis (VEGF/VEGFR-2) mediators. Overall, celecoxib and nintedanib association provided enhanced antitumor effects in TRAMP dorsolateral as compared to former registers in ventral prostate, thus demonstrating lobe-specific responses of this combined chemoprevention approach. Among these responses, we highlight the ability in promoting TGF-β signaling and its associated stromal maturation/stabilization, thus yielding a more quiescent stromal milieu and resulting in greater epithelial proliferation impairment.

Acidic Exo-Polysaccharide Obtained from Bacillus sp. NRC5 Attenuates Testosterone-DMBA-Induced Prostate Cancer in Rats via Inhibition of 5 α-Reductase and Na+/K+ ATPase Activity Mechanisms

Bacillus sp. NRC5 is a new strain that grows in Egyptian beaches. This strain produces acidic exo-polysaccharide that have excellent antioxidant, anti-inflammatory and anti-tumor properties. The current study aimed to introduce a new natural product feasible for prostate cancer therapies. The anti-prostate cancer of acidic exo-polysaccharide produced from marine Bacillus sp. NRC5 (EBPS) was determined using 7,12-dimethylbenz-(a)-anthracene; DMBA-induced prostate cancer in male Sprague Dawley rats. Rats were subcutaneously injected with testosterone (3 mg/kg/day for 3 months) and a single dose of DMBA (65 mg/kg) for induction of prostate cancer. EBPS was administrated orally at dose 200 mg/kg/day for 3 months. To study protective effect of EBPS, animals received EBPS before cancer induction, meanwhile in therapeutic effect animals received EBPS after cancer induction. EBPS debug oxidative stress and inflammatory conditions associated with prostate cancer. EBPS either protective or therapeutic material considerably reduced cancer growth rate-limiting enzyme-i.e., 5-α-reductase (46.89 ± 1.72 and 44.86 ± 2.56 µg Eq/mL) and Na⁺/K⁺ ATPase (0.44 ± 0.03 and 0.42 ± 0.02 µg Eq/mL), compared to cancer control (69.68 ± 3.46 µg Eq/mL). In addition, both cancer biomarkers-i.e., prostate-specific antigen and carcinoembryonic antigen were significantly lowered as evidence of the ability of EBPS to protect and treat prostate cancer in chemically induced rats. EBPS showed protective and therapeutic efficacy on testosterone-DMBA-induced prostate cancer rats with a good safety margin. This study may go to clinical trials after a repeated study on another type of small experimental animal, their offspring, and one big experimental animal.

Suppression of prostate cancer and amelioration of the immunosuppressive tumor microenvironment through selective immunoproteasome inhibition

New treatment options to battle hormone-refractory prostate carcinoma (PC) are a pressing medical need. Chronic inflammation has been implicated in PC etiology. The pro-inflammatory cytokines IL-6, IL-23 and IL-17 are key mediators to promote growth of PC. Here, we evaluate the potential of immunoproteasome inhibition for anti-inflammatory and direct anti-tumorigenic therapy of PC. The anti-tumor effect of immunoproteasome inhibitor ONX 0914 was tested in mouse and human PC cells and the in vivo therapeutic efficacy of immunoproteasome inhibition was analyzed in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice in preventive and therapeutic settings and in castration-resistant (CR)PC after castration. Inhibition of the immunoproteasome subunit LMP7 induced apoptotic cell death in PC cell lines. In TRAMP mice, ONX 0914-treatment resulted in significant inhibition of PC growth with a decreased frequency of malignant prostatic lesions and inhibition of metastasis formation. The number of immunosuppressive myeloid cells in PC was greatly reduced in response to ONX 0914. Thus, immunoproteasome inhibition shows remarkable efficacy against PC progression in vivo and impedes tumor recurrence in CRPC-TRAMP mice by blocking the immunosuppressive inflammatory response in the tumor microenvironment. In conclusion, we show that the immunoproteasome is a promising drug target for the treatment of PC.

Aspirin use and prostate tumor angiogenesis

PURPOSE

Aspirin use has been shown to be associated with reduced risk of aggressive prostate cancer, although the mechanisms are not fully understood.

METHODS

We examined associations between regular aspirin use and prostate tumor angiogenesis among 572 men from the Health Professionals Follow-up Study. Participants reported aspirin use on biennial questionnaires. Prostatectomy tumor blocks were immunostained for CD34 to assess microvessel size and irregularity. Multivariable linear regression was used to calculate percent differences in biomarker measures comparing use vs nonuse, and by duration and tablets per day.

RESULTS

Current aspirin users had larger vessel area (14.5%) and diameter (6.5%), and lower vessel irregularity (- 8.1%) compared to non-users, indicating a less angiogenic profile. Duration of use and current tablets per day were also associated with larger vessel diameter. Similar patterns were seen for low- and high-grade prostate cancers.

CONCLUSION

Our findings suggest that aspirin use, particularly current use, can lower prostate cancer carcinogenesis through angiogenic mechanisms.

Nutritional Risk and Assessment for Patients with Cancer Pain

BACKGROUND

The incidence of nutritional risk and malnutrition are high in patients with cancer pain. It is very important to choose an effective tool to identify these patients promptly. However, few studies have discussed this issue. The primary objective of this study is to clarify the similarities and differences between the two nutritional screening and assessment tools, and to estimate the anthropometry and biochemical indicators of the patients with cancer pain, with a view to provide help for treatment of these patients.

METHOD

Data of 146 patients with cancer pain were collected from August 2018 to May 2019 in the Pain Therapy Department of Tianjin Cancer Hospital. The information of numerical rating scale (NRS), nutritional risk screening-2002 (NRS-2002), patient-generated subjective global assessment (PG-SGA), anthropometry and biochemical indicators were collected for pain assessment, nutritional risk screening, and nutritional status assessment.

RESULTS

NRS scores had a positive correlation with NRS-2002 (R = 0.273, P = 0.001) and PG-SGA (R = 0.341, P = 0.000) separately. NRS-2002 and PG-SGA had a significant positive correlation with each other (R = 0.468, P = 0.000). NRS-2002 was finished in a shorter time period (4.2 ± 0.8 min vs. 12.8 ± 0.8 min, P = 0.001), while PG-SGA had a higher detection rate of malnutrition (86.3% vs. 65.8%). In the stepwise multiple regression analysis, NRS (0.258, P = 0.001), PA (-0.297, P = 0.000), TP (0.178, P = 0.030) are the indicators of NRS-2002; and NRS (0.317, P = 0.000), PA (β = 0.288, P = 0.000) and BMI (-0.281, P = 0.000) are the related variables of PG-SGA. The kappa coefficient was lower than 0.4 (kappa value = 0.396) when choosing the score of NRS-2002 ≥ 3 and PG-SGA ≥ 9 as the diagnostic criteria. If choosing the score of NRS-2002 ≥ 2 and PG-SGA ≥ 9, both the correlation coefficient (R = 0.699, P = 0.000) and the kappa coefficient (kappa value = 0.698, P = 0.000) became more coefficient.

CONCLUSIONS

Both NRS-2002 and PG-SGA could identify patients with nutritional risk and malnutrition accurately. NRS-2002 is simpler and takes less time to finish, while PG-SGA is more cumbersome with a higher detection rate of malnutrition. NRS, PA, TP and BMI are the most important reference indicators predicting on nutritional risk index and malnutrition status. We recommend NRS-2002 ≥ 2 as the diagnostic criteria in order to avoid missing the patients with nutritional risk.

Long chain omega-3 fatty acids and their oxidized metabolites are associated with reduced prostate tumor growth

INTRODUCTION

Cancer has been associated with increased oxidative stress and deregulation of bioactive oxylipins derived from long-chain polyunsaturated fatty acids (LC-PUFA) like arachidonic acid (AA). There is a debate whether ω-3 LC-PUFA could promote or prevent prostate tumor growth through immune modulation and reduction of oxidative stress. Our aim was to study the association between enzymatically or non-enzymatically produced oxidized-LC-PUFA metabolites and tumor growth in an immune-competent eugonadal and castrated C57BL/6 male mice injected with TRAMP-C2 prostate tumor cells, fed with ω-3 or ω-6 LC-PUFA-rich diets.

MATERIALS AND METHODS

Tumor fatty acids were profiled by gas chromatography and 26 metabolites derived from either AA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were assessed by liquid chromatography-mass spectrometry.

RESULTS

The enriched ω-3 diet did not reduce oxidative stress overall in tumors but favored the formation of ω-3 rather than ω-6 derived isoprostanoids. We discovered that EPA and its oxidized-derivatives like F₃-isoprostanes and prostaglandin (PG)F_3α, were inversely correlated with tumor volume (spearman correlations and T-test, p<0.05). In contrast, F₂-isoprostanes, adrenic acid, docosapentaenoic acid (DPA_ω-6) and PGE₂ were positively correlated with tumor volume. Interestingly, F₄-neuroprostanes, PGD₂, PGF_2α, and thromboxane were specifically increased in TRAMP-C2 tumors of castrated mice compared to those of eugonadal mice.

DISCUSSION

Decreasing tumor growth under ω-3 diet could be attributed in part to increased levels of EPA and its oxidized-derivatives, a reduced level of pro-angiogenic PGE₂ and increased levels of F₄-neuroprostanes and resolvins content in tumors, suspected of having anti-proliferative and anti-inflammatory effects.

Application of Anti-Inflammatory Agents in Prostate Cancer

Chronic inflammation is a major cause of human cancers. The environmental factors, such as microbiome, dietary components, and obesity, provoke chronic inflammation in the prostate, which promotes cancer development and progression. Crosstalk between immune cells and cancer cells enhances the secretion of intercellular signaling molecules, such as cytokines and chemokines, thereby orchestrating the generation of inflammatory microenvironment. Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) play pivotal roles in inflammation-associated cancer by inhibiting effective anti-tumor immunity. Anti-inflammatory agents, such as aspirin, metformin, and statins, have potential application in chemoprevention of prostate cancer. Furthermore, pro-inflammatory immunity-targeted therapies may provide novel strategies to treat patients with cancer. Thus, anti-inflammatory agents are expected to suppress the “vicious cycle” created by immune and cancer cells and inhibit cancer progression. This review has explored the immune cells that facilitate prostate cancer development and progression, with particular focus on the application of anti-inflammatory agents for both chemoprevention and therapeutic approach in prostate cancer.

Decreased biochemical progression in patients with castration-resistant prostate cancer using a novel mefenamic acid anti-inflammatory therapy: A randomized controlled trial

Prostate cancer (PCa) is the second most common non-dermatological cancer in men and is a growing public health problem. Castration-resistant disease (CRD) is the most advanced stage of the disease and is difficult to control. Patients with CRD may no longer accept conventional therapies as they are not in appropriate clinical conditions or they refuse to receive it. Given that inflammation is an essential component of CRD origin and progression, anti-inflammatory agents could be a therapeutic option with fenamates as one of the proposed choices. A prospective, randomized, double-blinded, 2-arm, parallel group, phase II-III clinical trial was performed involving 20 patients with CRD-PCa (with a prostate specific antigen level <100 ng/ml) that were undergoing androgen deprivation therapy (ADT) and did not accept any established treatment for that disease stage. In addition to ADT, 10 patients received placebo and 10 received mefenamic acid (500 mg orally every 12 h) for 6 months. The primary endpoint was the change in serum prostate-specific antigen (PSA) at 6 months. The PSA levels decreased significantly with mefenamic acid (an average 42% decrease), whereas there was an average 55% increase in the placebo group (P=0.024). In the patients treated with the placebo, 70% had biochemical disease progression (an increase of ≥25% in PSA levels), which did not occur in any of the patients treated with mefenamic acid (relative risk=0.12; 95% confidence interval, 0.01-0.85; P=0.033). There was a significant increase in quality of life (EQ-5D-5L score) and body mass index (BMI) with the experimental treatment. In conclusion, mefenamic acid administration decreased biochemical progression in patients with castration resistant PCa, improved their quality of life and increased their BMI. Future studies are required in order to strengthen the findings of the present clinical trial. Trial registration, Cuban Public Registry of Clinical Trials Database RPCEC00000248, August 2017.

Endoplasmic Reticulum Stress-Induced Resistance to Doxorubicin Is Reversed by Mulberry Leaf Polyphenol Extract in Hepatocellular Carcinoma through Inhibition of COX-2

Mulberry (Morus alba L.) leaves are used in Chinese medicine to treat metabolic disorders. Mulberry leaf polyphenol extracts (MLPE) have recently been shown to exhibit anticancer properties. Endoplasmic reticulum (ER) stress represents a pivotal obstacle in solid tumors, resulting in the antiapoptosis of tumor cells and drug resistance. In this study, pretreatment with the ER stress inducer tunicamycin (TM) attenuated the percentage of apoptosis induced by doxorubicin (DOX). Cotreatment with tunicamycin and MLPE reversed apoptosis induced by DOX. Simultaneously, induction of ER stress with tunicamycin resulted in an increased expression of Cyclooxygenase 2 (COX-2) and Glucose-regulated protein (GRP78) concomitant with the activation of p38 MAPK/PI3K/Akt in HepG2 cells. Furthermore, the suppression of ER stress with celecoxib or p38 MAPK inhibitor successfully recovered DOX-induced apoptosis. Consistent with the inhibition of COX-2 or p38 MAPK, copretreatment with TM and MLPE drastically recovered cytotoxicity and caspase-3 activation in the presence of DOX. These results reveal that MLPE reduces ER stress-induced resistance to DOX in hepatocellular carcinoma (HCC) cells through downregulation of COX-2- or p38 MAPK-mediated PI3K/Akt pathway.

Iodine Bonded with Milk Protein Inhibits Benign Prostatic Hyperplasia Development in Rats

BACKGROUND

There is some evidence that Benign Prostatic Hyperplasia (BPH) may increase the risk of developing prostate cancer, so conducting research on effective BPH inhibitors is important.

OBJECTIVE

This research studied the inhibitory effect of Iodized Serum Milk Protein (ISMP) on BPH in rats. ISMP is a concentrate of lactic protein containing 2.2% iodine.

METHODS

Male Wistar rats, aged 18 months, were used. In the intact control group, sunflower oil was administered intragastrically by gavage. In 36 rats, BPH was induced by surgical castration, followed by subcutaneous injections of prolonged testosterone - omnadren, 25mg/kg every other day (7 administrations). One group of rats served as BPH-control. ISMP and finasteride (positive control), dissolved in sunflower oil, were administered to rats intragastrically daily at a dose of 200μg/kg and 5mg/kg, respectively, for 4 weeks starting immediately after castration.

RESULTS

ISMP inhibited the development of BPH in rats, significantly reducing the mass of the prostate and its parts (except for the anterior lobes) by 1.1-1.3 times and the prostatic index (the ratio of prostate weight to the body weight) - by 1.3-1.4 times. Finasteride inhibited the development of BPH, and its activity was higher (by 1.1-1.3 times) than in ISMP. Histological analysis of the prostate showed fewer pronounced morphological hyperplasia signs in animals treated with ISMP or finasteride.

CONCLUSION

The iodine-containing preparation ISMP has the ability to inhibit the development of BPH in rats although its activity is somewhat lower than that of finasteride.

Aspirin Exposure and Mortality Risk among Prostate Cancer Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Prostate cancer (PCa) is the ninth most common cause of cancer death globally. Many studies have investigated aspirin exposure and mortality risk among PCa patients, returning inconsistent results. We conducted a comprehensive meta-analysis to explore the association between aspirin exposure and mortality risk among PCa patients and to investigate potential dose/duration/frequency-response relationships.

METHODS AND RESULTS

Studies published from 1980 to 2018 of PubMed and EMBASE databases were searched. We included 14 studies with 110,000 participants. Multivariate-adjusted odds ratios (ORs) were pooled using random-effect models. Potential dose/duration/frequency-response relationships were evaluated for aspirin exposure and prostate cancer-specific mortality (PCSM) risk. We did not detect an association between the highest aspirin exposure and mortality risk (PCSM of prediagnostic aspirin exposure, OR: 0.96, 95% confidence interval [CI]: 0.87-1. 07, I2= 0%; PCSM of postdiagnostic aspirin exposure, OR:0.92, 95% CI: 0.77-1.10, I2 = 56.9%; all-cause mortality [ACM] of prediagnostic aspirin exposure, OR: 0.96, 95% CI: 0.88-1.04, I2 = 9.4%; ACM of postdiagnostic aspirin exposure, OR: 0.95, 95% CI: 0.73-1.23, I2 = 88.9%). There was no significant dose/frequency-response association observed for aspirin exposure and PCSM risk. On duration-response analysis, we found that short-term postdiagnostic aspirin exposure (shorter than 2.5 years) increased the risk of PCSM.

CONCLUSIONS

Our meta-analysis suggests that there is no association between aspirin exposure and PCSM risk. Nor is there an association between the highest aspirin exposure and ACM risk among PCa patients. More studies are needed for a further dose/duration/frequency-response meta-analysis.

Association of anti-inflammatory and antiangiogenic therapies negatively influences prostate cancer progression in TRAMP mice

BACKGROUND

Chronic inflammation has been implicated in cancer etiology and angiogenesis is stimulated in this disease. In prostate, the crosstalk between malignant epithelial cells and their microenvironment is an essential step of tumorigenesis during which glandular stroma undergo changes designated as reactive stroma. Thus, the aim herewith was to evaluate the effects of associating anti-inflammatory and antiangiogenic therapies on cancer progression, correlating them with steroid hormone receptor (AR and ERα), reactive stroma (vimentin, αSMA, and TGF-β), and cell proliferation (PCNA) markers expression in the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model.

METHODS

TRAMP mice (12-week old) were divided into the groups: Control (TRCON): received the vehicles used for drug dilution; Celecoxib (TRCEL): received oral doses of the anti-inflammatory drug celecoxib (15 mg/kg) twice daily; Nintedanib (TRNTB): received oral doses of the antiangiogenic drug nintedanib (10 mg/kg) daily; Nintedanib+Celecoxib (TRNTCEL): received the combination of drugs. After 6 weeks, mice were euthanized and ventral prostate samples were harvested for morphological, immunohistochemical, and Western blotting analyses.

RESULTS

While celecoxib led to fibromuscular hypertrophy attenuation, nintedanib significantly reduced the incidence of well-differentiated adenocarcinoma (WDAC) foci in relation to controls, both when administered per se or in association to celecoxib. Furthermore, drug combination was associated with unique effects, including lower incidence of HGPIN lesions; lower AR stromal distribution; changes in ERα localization from epithelial nuclei to stroma as well as significant decrease of TGF-β levels and associated angiogenesis. In parallel, all treatments applied resulted in reduced inflammatory marker and vimentin (VIM) expression.

CONCLUSIONS

Celecoxib plus nintedanib is an effective antitumor combination against prostate cancer progression in TRAMP mice, showing remarkable efficacy in relation to isolated therapies. Importantly, this efficacy might be due to drug association effect on driving AR and mainly ERα distribution in the prostatic tissue towards benign patterns. In addition, celecoxib and nintedanib impaired the development of a stromal reaction by reducing the recruitment of reactive stroma cells and maintaining a normal smooth muscle cell-rich prostate stroma in TRAMP mice. Collectively, these findings pointed to the beneficial effects of combining anti-inflammatory and antiangiogenic strategies to prevent or delay prostatic tumorigenesis.

Contribution of Nrf2 Modulation to the Mechanism of Action of Analgesic and Anti-inflammatory Drugs in Pre-clinical and Clinical Stages

Despite the progress that has occurred in recent years in the development of therapies to treat painful and inflammatory diseases, there is still a need for effective and potent analgesics and anti-inflammatory drugs. It has long been known that several types of antioxidants also possess analgesic and anti-inflammatory properties, indicating a strong relationship between inflammation and oxidative stress. Understanding the underlying mechanisms of action of anti-inflammatory and analgesic drugs, as well as essential targets in disease physiopathology, is essential to the development of novel therapeutic strategies. The Nuclear factor-2 erythroid related factor-2 (Nrf2) is a transcription factor that regulates cellular redox status through endogenous antioxidant systems with simultaneous anti-inflammatory activity. This review summarizes the molecular mechanisms and pharmacological actions screened that link analgesic, anti-inflammatory, natural products, and other therapies to Nrf2 as a regulatory system based on emerging evidences from experimental disease models and new clinical trial data.

Preventative effect of celecoxib in dimethylbenz[a]anthracene-induced ovarian cancer in rats

PURPOSE

The present study investigated the preventive effect of the cyclooxygenase (COX)-2 inhibitor, celecoxib, in 7,12-dimethylbenz[a]anthracene (DMBA)-induced ovarian cancer in a rat model.

METHODS

A diet containing celecoxib (1500 ppm) was started 2 weeks before the introduction of DMBA. DMBA-soaked cotton threads were surgically applied to induce ovarian cancer in female Wistar rats. Tumor growth and survival were observed for 24 weeks.

RESULTS

During the study period, an overall tumor incidence of 97.5% was observed and 65% of tumors were ovarian adenocarcinoma. The celecoxib diet significantly reduced the incidence and size of DMBA-induced ovarian cancers and significantly improved survival of tumor-bearing rats. The preventive effect of celecoxib was associated with increased apoptosis.

CONCLUSION

DMBA-induced ovarian cancer in rats recapitulates many pathophysiological features of the human counterpart. Our results provide supportive evidence that celecoxib has a preventive effect on development of ovarian cancer in a rat model.

COX-2 mediates pro-tumorigenic effects of PKCε in prostate cancer

The pro-oncogenic kinase PKCε is overexpressed in human prostate cancer and cooperates with loss of the tumor suppressor Pten for the development of prostatic adenocarcinoma. However, the effectors driving PKCε-mediated phenotypes remain poorly defined. Here, using cellular and mouse models, we showed that PKCε overexpression acts synergistically with Pten loss to promote NF-κB activation and induce cyclooxygenase-2 (COX-2) expression, phenotypic traits which are also observed in human prostate tumors. Targeted disruption of PKCε from prostate cancer cells impaired COX-2 induction and PGE2 production. Notably, COX-2 inhibitors selectively killed prostate epithelial cells overexpressing PKCε, and this ability was greatly enhanced by Pten loss. Long-term COX-2 inhibition markedly reduced adenocarcinoma formation, as well as angiogenesis in a mouse model of prostate-specific PKCε expression and Pten loss. Overall, our results provide strong evidence for the involvement of the canonical NF-κB pathway and its target gene COX2 as PKCε effectors, and highlight the potential of PKCε as a useful biomarker for the use of COX inhibition for chemopreventive and/or chemotherapeutic purposes in prostate cancer.

Do Aspirin and Other NSAIDs Confer a Survival Benefit in Men Diagnosed with Prostate Cancer? A Pooled Analysis of NIH-AARP and PLCO Cohorts

Prostate cancer is one of the leading causes of cancer-related death in U.S. men. There is an unmet need to identify modifiable risk factors for prostate cancer survival. Experimental studies have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) may improve prostate cancer survival through antithrombotic and anti-inflammation mechanisms. Results from previous observational studies have been equivocal, and few have assessed whether an etiologically relevant time window of exposure exists. We sampled incident prostate cancer cases from two large U.S. prospective cohorts, NIH-AARP Diet and Health Study and PLCO Cancer Screening Trial, to investigate whether pre- and postdiagnostic aspirin and non-aspirin NSAID use were associated with prostate cancer-specific and all-cause mortality. Cox proportional hazards regression models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). Study-specific results were meta-analyzed using fixed-effects models. Pre- and postdiagnostic aspirin or non-aspirin NSAID use were not statistically significantly associated with prostate cancer-specific mortality. However, occasional (less than daily) and daily aspirin users five years or more before prostate cancer diagnosis had 18% (HR = 0.82; 95% CI = 0.75-0.90) and 15% (HR = 0.85; 95% CI = 0.77-0.94) reduced all-cause mortality versus nonusers. Similarly, postdiagnostic occasional and daily aspirin use were associated with 17% (HR = 0.83; 95% CI=0.72-0.95) and 25% (HR = 0.75; 95% CI = 0.66-0.86) reduced all-cause mortality, independent of prediagnostic aspirin use. This study suggests that aspirin or non-aspirin NSAIDs are not associated with prostate cancer survival. However, aspirin use both before and after prostate cancer diagnosis was associated with longer overall survival, highlighting the importance of comorbidity prevention among prostate cancer survivors. Cancer Prev Res; 10(7); 410-20. ©2017 AACR.

Goniothalamin and Celecoxib Effects During Aging: Targeting Pro-Inflammatory Mediators in Chemoprevention of Prostatic Disorders

BACKGROUND

Prostate is highly affected by aging, which lead to inflammatory disorders that can predispose to cancer development. Chemoprevention has emerged as a new therapeutic approach, intensifying studies evaluating the biological properties of new compounds. The aim of this study was to characterize the inflammatory responses in the prostate ventral lobe from senile mice treated with Goniothalamin (GTN), a promising natural compound with anti-inflammatory and antiproliferative properties. Its activity was compared to Celecoxib, an established nonsteroidal anti-inflammatory drug (NSAID).

METHODS

The animals were divided into: Control groups; Young (18-week-old FVB), Senile (52-week-old FVB). Treated groups: Senile-Goniothalamin (150 mg/kg orally), Senile-Celecoxib (10 mg/kg orally). The ventral lobe was collected after 4 weeks for light microscopy, immunohistochemistry, ELISA, and Western blotting analysis.

RESULTS

Both treatments were efficient in controlling the inflammatory process in the prostate from senile mice, maintaining the glandular morphology integrity. GTN reduced all inflammatory mediators evaluated (TNF-α, COX-2, iNOS) and different from Celecoxib, it also decreased the protein levels of NF-kB and p-NF-kB.

CONCLUSIONS

Finally, GTN and Celecoxib controlled inflammation in the prostate, and sensitized the senescent microenvironment to anti-inflammatory stimuli. Thus, both treatments are indicated as potential drugs in the prostatic diseases prevention during senescence. Prostate 77:838-848, 2017. © 2017 Wiley Periodicals, Inc.

Oral administration of withaferin A inhibits carcinogenesis of prostate in TRAMP model

We previously reported that withaferin A (WA), a natural compound, deters prostate cancer by inhibiting AKT while inducing apoptosis. In the current study, we examined its chemopreventive efficacy against carcinogenesis in the prostate using the transgenic adenocarcinoma of mouse prostate (TRAMP) model. Two distinct sets of experiments were conducted. To determine whether WA delays tumor progression, it was given before cancer onset, at week 6, and until week 44. To determine its effect after the onset of prostate cancer, it was given from weeks 12 to 35. In both strategies, oral administration of WA effectively suppressed tumor burden when compared to vehicle-treated animals. No toxicity was seen in treated animals at gross pathological examination. Western blot analysis and immunohistochemistry of tumor sections revealed that in TRAMP controls, AKT and pAKT were highly expressed while nuclear FOXO3a and Par-4 were downregulated. On the contrary, treated mice showed inhibition of AKT signaling and activation of FOX03a-Par-4-induced cell death. They also displayed inhibition of mesenchymal markers such as β-catenin, vimentin, and snail as well as upregulation of E-cadherin. Because expressions of the angiogenic markers factor VIII and retic were downregulated, an anti-angiogenic role of WA is suggested. Overall, our results suggest that WA could be a promising anti-cancer agent that effectively inhibits carcinogenesis of the prostate.

Optimizing mouse models for precision cancer prevention

As cancer has become increasingly prevalent, cancer prevention research has evolved towards placing a greater emphasis on reducing cancer deaths and minimizing the adverse consequences of having cancer. 'Precision cancer prevention' takes into account the collaboration of intrinsic and extrinsic factors in influencing cancer incidence and aggressiveness in the context of the individual, as well as recognizing that such knowledge can improve early detection and enable more accurate discrimination of cancerous lesions. However, mouse models, and particularly genetically engineered mouse (GEM) models, have yet to be fully integrated into prevention research. In this Opinion article, we discuss opportunities and challenges for precision mouse modelling, including the essential criteria of mouse models for prevention research, representative success stories and opportunities for more refined analyses in future studies.

Obesity and cancer: mechanistic insights from transdisciplinary studies

Obesity is associated with a range of health outcomes that are of clinical and public health significance, including cancer. Herein, we summarize epidemiologic and preclinical evidence for an association between obesity and increased risk of breast and prostate cancer incidence and mortality. Moreover, we describe data from observational studies of weight change in humans and from calorie-restriction studies in mouse models that support a potential role for weight loss in counteracting tumor-promoting properties of obesity in breast and prostate cancers. Given that weight loss is challenging to achieve and maintain, we also consider evidence linking treatments for obesity-associated co-morbidities, including metformin, statins and non-steroidal anti-inflammatory drugs, with reduced breast and prostate cancer incidence and mortality. Finally, we highlight several challenges that should be considered when conducting epidemiologic and preclinical research in the area of obesity and cancer, including the measurement of obesity in population-based studies, the timing of obesity and weight change in relation to tumor latency and cancer diagnosis, and the heterogeneous nature of obesity and its associated co-morbidities. Given that obesity is a complex trait, comprised of behavioral, epidemiologic and molecular/metabolic factors, we argue that a transdisciplinary approach is the key to understanding the mechanisms linking obesity and cancer. As such, this review highlights the critical need to integrate evidence from both epidemiologic and preclinical studies to gain insight into both biologic and non-biologic mechanisms contributing to the obesity-cancer link.

Nonsteroidal anti-inflammatory drugs and prostatic diseases

Prostatic diseases are characterized by increased activity of cytokines, growth factors, and cyclooxygenases- (COX-) 1 and 2. Activation of COX-1 and COX-2 results in increased levels of prostaglandins and the induction of angiogenic, antiapoptotic and inflammatory processes. Inhibition of COX enzymes by members of the widely used nonsteroidal anti-inflammatory drug (NSAID) class of drugs decreases prostaglandin production, and exerts a variety of anti-inflammatory, antipyretic, and antinociceptive effects. While numerous in vitro, in vivo, and clinical studies have shown that NSAIDs inhibit the risk and progression of prostatic diseases, the relationship between NSAIDs and such diseases remains controversial. Here we review the literature in this area, critically analyzing the benefits and caveats associated with the use of NSAIDs in the treatment of prostatic diseases.

Antitumor effects of celecoxib in COX-2 expressing and non-expressing canine melanoma cell lines

Cyclooxygenase-2 (COX-2) is a potential target for chemoprevention and cancer therapy. Celecoxib, a selective COX-2 inhibitor, inhibits cell growth of various types of human cancer including malignant melanoma. In dogs, oral malignant melanoma represents the most common oral tumor and is often a fatal disease. Therefore, there is a desperate need to develop additional therapeutic strategies. The purpose of this study was to investigate the anticancer effects of celecoxib on canine malignant melanoma cell lines that express varying levels of COX-2. Celecoxib induced a significant anti-proliferative effect in both LMeC and CMeC-1 cells. In the CMeC cells, treatment of 50 μM celecoxib caused an increase in cells in the G0/G1 and a decreased proportion of cells in G-2 phase. In the LMeC cells, 50 μM of celecoxib led to an increase in the percentage of cells in the sub-G1 phase and a significant activation of caspase-3 when compared to CMeC-1 cells. In conclusion, these results demonstrate that celecoxib exhibits antitumor effects on canine melanoma LMeC and CMeC-1 cells by induction of G1-S cell cycle arrest and apoptosis. Our data suggest that celecoxib might be effective as a chemotherapeutic agent against canine malignant melanoma.

SNAI1 is critical for the aggressiveness of prostate cancer cells with low E-cadherin

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 E-cadherin (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 E-cadherin 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 E-cadherin 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.

Iodine uptake and prostate cancer in the TRAMP mouse model

Iodine supplementation exerts antitumor effects in several types of cancer. Iodide (I⁻) and iodine (I₂) reduce cell proliferation and induce apoptosis in human prostate cancer cells (LNCaP and DU-145). Both chemical species decrease tumor growth in athymic mice xenografted with DU-145 cells. The aim of this study was to analyze the uptake and effects of iodine in a preclinical model of prostate cancer (transgenic adenocarcinoma of the mouse prostate [TRAMP] mice/SV40-TAG antigens), which develops cancer by 12 wks of age. ¹²⁵I⁻ and ¹²⁵I₂ uptake was analyzed in prostates from wild-type and TRAMP mice of 12 and 24 wks in the presence of perchlorate (inhibitor of the Na⁺/I⁻ symporter [NIS]). NIS expression was quantified by quantitative polymerase chain reaction (qPCR). Mice (6 wks old) were supplemented with 0.125 mg I⁻ plus 0.062 mg I₂/mouse/day for 12 or 24 wks. The weight of the genitourinary tract (GUT), the number of acini with lesions, cell proliferation (levels of proliferating cell nuclear antigen [PCNA] by immunohistochemistry), p53 and p21 expression (by qPCR) and apoptosis (relative amount of nucleosomes by enzyme-linked immunosorbent assay) were evaluated. In both age-groups, normal and tumoral prostates take up both forms of iodine, but only I⁻ uptake was blocked by perchlorate. Iodine supplementation prevented the overexpression of NIS in the TRAMP mice, but had no effect on the GUT weight, cell phenotype, proliferation or apoptosis. In TRAMP mice, iodine increased p53 expression but had no effect on p21 (a p53-dependent gene). Our data corroborate NIS involvement in I⁻ uptake and support the notion that another transporter mediates I₂ uptake. Iodine did not prevent cancer progression. This result could be explained by a strong inactivation of the p53 pathway by TAG antigens.

Lack of high-dose radiation mediated prostate cancer promotion and low-dose radiation adaptive response in the TRAMP mouse model

Cancer of the prostate is a highly prevalent disease with a heterogeneous aetiology and prognosis. Current understanding of the biological mechanisms underlying the responses of prostate tissue to ionizing radiation exposure, including cancer induction, is surprisingly limited for both high- and low-dose exposures. As population exposure to radiation increases, largely through medical imaging, a better understanding of the response of the prostate to radiation exposure is required. Low-dose radiation-induced adaptive responses for increased cancer latency and decreased cancer frequency have been demonstrated in mouse models, largely for hematological cancers. This study examines the effects of high- and low-dose whole-body radiation exposure on prostate cancer development using an autochthonous mouse model of prostate cancer: TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP). TRAMP mice were exposed to single acute high (2 Gy), low (50 mGy) and repeated low (5 × 50 mGy) doses of X rays to evaluate both the potential prostate cancer promoting effects of high-dose radiation and low-dose adaptive response phenomena in this prostate cancer model. Prostate weights and histopathology were examined to evaluate gross changes in cancer development and, in mice exposed to a single 2 Gy dose, time to palpable tumor was examined. Proliferation (Ki-67), apoptosis, DNA damage (γ-H2AX) and transgene expression (large T-antigen) were examined within TRAMP prostate sections. Neither high- nor low-dose radiation-induced effects on prostate cancer progression were observed for any of the endpoints studied. Lack of observable effects of high- or low-dose radiation exposure suggests that modulation of tumorigenesis in the TRAMP model is largely resistant to such exposures. However, further study is required to better assess the effects of radiation exposure using alternative prostate cancer models that incorporate normal prostate and in those that are not driven by SV40 large T antigen.

Nonsteroidal anti-inflammatory drugs and prostate cancer: a systematic review of the literature and meta-analysis

Prostate cancer is the most common visceral cancer in men. Many studies have shown that nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the risk of prostate cancer. We systematically searched all relevant databases (MEDLINE, EMBASE, The Cochrane Collaboration, CINAHL, Database of Abstracts of Review of Effects and ACP Journal Club) to March 2008. We also explored bibliographies of the articles, pertinent journals and conferences. We selected relevant articles according to predefined inclusion criteria by 2 independent reviewers. We used both fixed and random-effect models for meta-analysis. We performed subgroup and sensitivity analysis based on predefined variables. From 962 extracted articles, 20 met the inclusion criteria with a total of 25 768 participants. All the studies had an observational design. There was a statistically significant protective effect for NSAIDs on risk of prostate cancer (odds ratio [OR] 0.92, 95% confidence interval [CI] 0.86-0.97). Subgroup analysis did not show any effect of study design or quality score on the results. There was a small but statistically significant protective effect for acetylsalicylic acid (ASA) (OR 0.95, 95% CI 0.91-1.00). Exposure to non-ASA NSAIDs was associated with a slightly reduced likelihood of prostate cancer (OR 0.92, 95% CI 0.85-1.00). With the available data, we were not able to determine an optimum dosage for NSAIDs. We conclude that taking NSAIDs may reduce the risk of prostate cancer. Nevertheless, the effect is small.

The Prostate Cancer Patient Had Higher C-Reactive Protein Than BPH Patient

Purpose

C-reactive protein (CRP) is a general marker for inflammation and it has been associated with prostate cancer. We hypothesized that a correlation may exist between CRP and prostate cancer in patients undergoing transrectal biopsy of the prostate because of rising prostate-specific antigen (PSA) levels.

Materials and Methods

From January 2009 to March 2012, we retrospectively reviewed 710 patients who visited our urology department and were diagnosed as having a PSA value over 4.0 ng/mL. Patients with acute infections, rheumatoid arthritis, gout, asthma, chronic lung disease, myocardial infarction, or apoplexy and those who had taken nonsteroidal anti-inflammatory drugs were exempted from the research because these variables could have impacted CRP. After we applied the exclusion criteria, we selected 63 patients with prostate cancer and 140 patients with benign prostatic hyperplasia (BPH).

Results

A total of 203 patients were observed: 140 patients had BPH, and 63 patients had prostate cancer. Prostate cancer patients were divided into two groups by tumor-node-metastasis classification. The patients below T2 were group A, and those above T3 were group B. The natural logarithm of C-reactive protein (lnCRP) differed between the BPH group and the prostate cancer group. The lnCRP also differed between the BPH group and prostate cancer groups A and B (p<0.05).

Conclusions

The serum CRP level of the prostate cancer group was higher than that of the BPH group. Inflammation may be correlated with prostate cancer according to the serum CRP level.

Anastrozole and celecoxib for endometriosis treatment, good to keep them apart?

Endometriosis is a benign gynecological disease. Cyclooxygenase-2 (COX-2) and aromatase proteins have been shown to be overexpressed in eutopic endometrium from women suffering from this disease compared to disease-free women. Furthermore, inhibition of these molecules individually was demonstrated to have antiproliferative and proapoptotic effects both in vitro and in vivo in several models. In this study, the effect of combining celecoxib, a selective COX-2 inhibitor, and anastrozole, an aromatase inhibitor, on the implantation and growth of endometriotic like lesions in a murine model of endometriosis was evaluated. Endometriosis was surgically induced in female BALB/c mice. After 28 days of treatment with celecoxib, anastrozole, or their combination, animals were killed and lesions were counted, measured, excised, and fixed. Immunohistochemistry for proliferating cell nuclear antigen and CD34 was performed for assessment of cell proliferation and vascularization. TUNEL technique was performed for apoptosis evaluation. Celecoxib was the only treatment to significantly reduce the number of lesions established per mouse, their size and vascularized area. In addition, cell proliferation was significantly diminished and apoptosis was significantly enhanced by both individual treatments. When the therapies were combined, they reversed their effects. These results confirm that celecoxib and anastrozole separately decrease endometriotic growth, but when combined they might have antagonizing effects.

11β-Hydroxysteroid Dehydrogenase Type II is a Potential Target for Prevention of Colorectal Tumorigenesis

Colorectal cancer (CRC) is a leading cause of cancer death, yet primary prevention remains the best approach to reducing overall morbidity and mortality. There is a clear molecular link between cyclooxygenase-2 (COX-2)-derived prostaglandin E₂ (PGE₂) production and CRC progression. Although selective COX-2 inhibitors as well as non-steroidal anti-inflammatory drugs (NSAIDs) reduce the number and sizes of colonic adenomas, increased cardiovascular risks of selective COX-2 inhibitors and increased gastrointestinal side-effects of NSAIDs limit their use in chemoprevention of CRC. Glucocorticoids induce apoptosis and are endogenous, potent COX-2 inhibitors. Glucocorticoids have been used for the treatment of hematologic malignancies, but not for solid tumors due to adverse side-effects such as immunosuppression and osteoporosis. In tissues, glucocorticoid actions are down-regulated by t y p e 2 1 1 β-hydroxysteroid dehydrogenase (11βHSD2), and inhibition of 11βHSD2 activity will elevate intracellular active glucocorticoid to levels that effectively suppress COX-2 expression. Both COX-2 and 11βHSD2 increase in Apc^+/min mouse intestinal adenomas and human colonic adenomas and either pharmacologic or genetic 11βHSD2 inhibition leads to decreases in COX-2-mediated PGE₂ production in tumors and prevents adenoma formation, tumor growth, and metastasis. 11βHSD2 inhibition may represent a novel approach for CRC chemoprevention by increasing tumor cell intracellular glucocorticoid activity, which in turn inhibits tumor growth by suppressing the COX-2-derived PGE₂ pathway, as well as other pathways, without potential side-effects relating to chronic application of COX-2 inhibitors, NSAIDs and glucocorticoids.

The role of vitamin D in cancer prevention and treatment

Considerable data described in the first part of this review suggest that there is a role for vitamin D in cancer therapy and prevention. Although the preclinical data are persuasive and the epidemiologic data intriguing, no well-designed clinical trial of optimal administration of vitamin D as a cancer therapy has ever been conducted. Had there been the opportunity and insight to develop calcitriol as any other cancer drug, the following studies would have been completed: 1. Definition of the MTD. 2. Definition of a phase II dose, as a single agent and in combination with cytotoxic agents. 3. Studies to define a biologically optimal dose. 4. Phase II (probably randomized phase II) studies of calcitriol alone and chemotherapy ± calcitriol. 5. Then, randomized phase III trials would be conducted and designed such that the only variable was the administration of calcitriol. Prerequisites 1 to 5 have not been completed for calcitriol. Preclinical data provide considerable rationale for continued development of vitamin D analogue-based cancer therapies. However, design of future studies should be informed by good clinical trials design principles and the mistakes of the past not repeated. Such studies may finally provide compelling data to prove whether or not there is a role for vitamin D analogues in cancer therapy.

A high-fat diet containing whole walnuts (Juglans regia) reduces tumour size and growth along with plasma insulin-like growth factor 1 in the transgenic adenocarcinoma of the mouse prostate model

Prostate cancer (PCa) has been linked to fat intake, but the effects of both different dietary fat levels and types remain inconsistent and incompletely characterised. The effects on PCa in the transgenic adenocarcinoma of the mouse prostate (TRAMP) cancer model of an elevated fat (20 % of energy as fat) diet containing 155 g of whole walnuts were compared to those of an elevated fat (20 % of energy as soyabean oil) diet with matched macronutrients, tocopherols as well as a low-fat (8 % of energy as soyabean oil) diet. Mice, starting at 8 weeks of age, consumed one of the three different diets ad libitum; and prostates, livers and blood were obtained after 9, 18 or 24 weeks of feeding. No differences were observed in whole animal growth rates in either high-fat (HF) diet group, but prostate tumour weight and growth rate were reduced in the walnut diet group. Walnut diet group prostate weight, plasma insulin-like growth factor 1, resistin and LDL were lower at 18 weeks, while no statistically significant prostate weight differences by diet were seen at 9 or 24 weeks. Multiple metabolites in the livers differed by diet at 9 and 18 weeks. The walnut diet's beneficial effects probably represent the effects of whole walnuts' multiple constituents and not via a specific fatty acid or tocopherols. Moreover, as the two HF diets had dissimilar effects on prostate tumour growth rate and size, and yet had the same total fat and tocopherol composition and content, this suggests that these are not strongly linked to PCa growth.

Vitamin D metabolism and action in the prostate: implications for health and disease

Prostate cancer (PCa) is the second most common cancer in men worldwide. Epidemiological, molecular, and cellular studies have implicated vitamin D deficiency as a risk factor for the development and/or progression of PCa. Studies using cell culture systems and animal models suggest that vitamin D acts to reduce the growth of PCa through regulation of cellular proliferation and differentiation. However, although preclinical studies provide a strong indication for anti-cancer activity, proof of therapeutic benefits in men is still lacking. The anti-proliferative and pro-differentiating properties of vitamin D have been attributed to calcitriol [1,25(OH)(2)D(3)], the hormonally active form of vitamin D, acting through the vitamin D receptor (VDR). Metabolism of vitamin D in target tissues is mediated by two key enzymes: 1α-hydroxylase (CYP27B1), which catalyzes the synthesis of calcitriol from 25(OH)D and 24-hydroxylase (CYP24), which catalyzes the initial step in the conversion of calcitriol to less active metabolites. Many factors affect the balance of calcitriol synthesis and catabolism and several maneuvers, like combination therapy of calcitriol with other drugs, have been explored to treat PCa and reduce its risk. The current paper is an overview addressing some of the key factors that influence the biological actions of vitamin D and its metabolites in the treatment and/or prevention of PCa.

The in vivo expression of radiation-induced chromosomal instability has an inflammatory mechanism

Ionizing radiation is unequivocally leukemogenic and carcinogenic, and this is generally attributed to DNA damage arising as a consequence of deposition of energy in the cell nucleus at the time of exposure. However, nontargeted effects, in which DNA damage is produced in nonirradiated cells as a consequence of cell signaling processes, indicate additional mechanisms. Radiation-induced chromosomal instability, a nontargeted effect with the potential to produce pathological consequences, is characterized by an increased rate of chromosome aberrations many generations after the initial insult. In this study, using a mouse model that has been well characterized with respect to its susceptibility to both radiation-induced chromosomal instability and acute myeloid leukemia, we investigated whether the underlying signaling mechanism was an inflammatory process by studying the effects of a nonsteroidal anti-inflammatory drug. Treated mice showed significant reduction in expression of the chromosomal instability phenotype 100 days postirradiation associated with reduced expression of inflammatory markers. The data support the hypothesis that the radiation-induced chromosomal instability phenotype is not an intrinsic property of the cells but a consequence of inflammatory processes having the potential to contribute secondary damage expressed as nontargeted and delayed radiation effects.

Regulation of inflammation in cancer by eicosanoids

Inflammation in the tumor microenvironment is now recognized as one of the hallmarks of cancer. Endogenously produced lipid autacoids, locally acting small molecule lipid mediators, play a central role in inflammation and tissue homeostasis, and have recently been implicated in cancer. A well-studied group of autacoid mediators that are the products of arachidonic acid metabolism include: the prostaglandins, leukotrienes, lipoxins and cytochrome P450 (CYP) derived bioactive products. These lipid mediators are collectively referred to as eicosanoids and are generated by distinct enzymatic systems initiated by cyclooxygenases (COX 1 and 2), lipoxygenases (5-LOX, 12-LOX, 15-LOXa, 15-LOXb), and cytochrome P450s, respectively. These pathways are the target of approved drugs for the treatment of inflammation, pain, asthma, allergies, and cardiovascular disorders. Beyond their potent anti-inflammatory and anti-cancer effects, non-steroidal anti-inflammatory drugs (NSAIDs) and COX-2 specific inhibitors have been evaluated in both preclinical tumor models and clinical trials. Eicosanoid biosynthesis and actions can also be directly influenced by nutrients in the diet, as evidenced by the emerging role of omega-3 fatty acids in cancer prevention and treatment. Most research dedicated to using eicosanoids to inhibit tumor-associated inflammation has focused on the COX and LOX pathways. Novel experimental approaches that demonstrate the anti-tumor effects of inhibiting cancer-associated inflammation currently include: eicosanoid receptor antagonism, overexpression of eicosanoid metabolizing enzymes, and the use of endogenous anti-inflammatory lipid mediators. Here we review the actions of eicosanoids on inflammation in the context of tumorigenesis. Eicosanoids may represent a missing link between inflammation and cancer and thus could serve as therapeutic target(s) for inhibiting tumor growth.

Lobe-specific lineages of carcinogenesis in the transgenic adenocarcinoma of mouse prostate and their responses to chemopreventive selenium

BACKGROUND

The transgenic adenocarcinoma of mouse prostate (TRAMP) model is by far the most practical transgenic model for preclinical prostate cancer chemoprevention studies. It is critical to characterize the prostate lobe-specificity of lesion lineages to consolidate the advantages of this model and minimize its limitations for chemoprevention studies.

METHODS

We dissected dorsolateral (DLP), ventral (VP), and anterior prostate (AP) lobes, and macroscopic tumors from 90 male C57BL/6J TRAMP mice at 22-24 weeks of age (WOA) and analyzed lesions by histological, biochemical and proteomic approaches. To determine whether methylseleninic acid (MSeA) led to a deletion of initiated cells, we gave oral MSeA to TRAMP mice from 5 to 23 WOA or from 5 to 15 WOA and analyzed lesions at 23 WOA.

RESULTS

All tumors (n = 18) were T-antigen(+), synaptophysin (SYP)(+), androgen-receptor(-), and E-cadherin(-) poorly differentiated neuroendocrine carcinomas (NE-Ca). They were traceable most frequently to VP (66.7%) and rarely to DLP (11.1%) and AP (5.6%) with an estimated life-time incidence of 1 out of 3 mice. In DLP, epithelial lesions ranged from mild-to-severe atypical hyperplasia, with T-antigen(+), SYP(-), androgen-receptor(+), and E-cadherin(+). Proteomic profiling revealed many molecular differences between VP and DLP. In MSeA experiment, 6 out of 19 (31.5%) mice developed NE-Ca in the control group, only 2 in each MSeA group of 17-18 mice (11.1-11.8%) bore a detectable NE-Ca.

CONCLUSION

The C57BL/6J TRAMP mouse represents at least two lineages of prostate carcinogenesis. Chemoprevention studies should incorporate this knowledge for efficacy assessment and molecular target validations.

Regulation of bombesin-stimulated cyclooxygenase-2 expression in prostate cancer cells

Background

Cyclooxygenase-2 (COX-2) and the bombesin (BBS)-like peptide, gastrin-releasing peptide (GRP), have been implicated in the progression of hormone-refractory prostate cancer; however, a mechanistic link between the bioactive peptide and COX-2 expression in prostate cells has not been made.

Results

We report that BBS stimulates COX-2 mRNA and protein expression, and the release of prostaglandin E₂ from the GRP receptor (GRPR)-positive, androgen-insensitive prostate cancer cell line, PC-3. BBS-stimulated COX-2 expression is mediated, in part, by p38^MAPK and PI3 kinase (PI3K)/Akt pathways, and blocked by a GRPR antagonist. The PI3K/Akt pathway couples GRPR to the transcription factor, activator protein-1 (AP-1), and enhanced COX-2 promoter activity. Although BBS stimulates nuclear factor-kappaB (NF-κB) in PC-3, NF-κB does not regulate GRPR-mediated COX-2 expression. The p38^MAPK pathway increases BBS-stimulated COX-2 expression by slowing the degradation of COX-2 mRNA. Expression of recombinant GRPR in the androgen-sensitive cell line LNCaP is sufficient to confer BBS-stimulated COX-2 expression via the p38^MAPK and PI3K/Akt pathways.

Conclusions

Our study establishes a mechanistic link between GRPR activation and enhanced COX-2 expression in prostate cancer cell lines, and suggests that inhibiting GRPR may, in the future, provide an effective therapeutic alternative to non-steroidal anti-inflammatory drugs for inhibiting COX-2 in patients with recurrent prostate cancer.

Vitamin D and cancer: deciphering the truth

Vitamin D is a hormone-like micronutrient involved not only in calcium metabolism but also in a variety of biological activities (e.g., cell proliferation, apoptosis, angiogenesis, inflammation) that makes it a candidate anticancer agent. Preclinical studies support the therapeutic potential of vitamin D both alone and in combination with other therapeutics. Overall, epidemiological data suggest the existence of a link between vitamin D and cancer risk, whereas the results of clinical trials are quite conflicting. This article is a comprehensive and balanced overview of the current evidence in an attempt to critically interpret the wealth of scientific data thus far produced on this research field and to rationally envisage the next steps necessary to define the role of vitamin D in the therapeutic management of cancer.

Serum phospholipid fatty acids and prostate cancer risk: results from the prostate cancer prevention trial

Inflammation may be involved in prostate cancer development and progression. This study examined the associations between inflammation-related phospholipid fatty acids and the 7-year-period prevalence of prostate cancer in a nested case-control analysis of participants, aged 55-84 years, in the Prostate Cancer Prevention Trial during 1994-2003. Cases (n = 1,658) were frequency matched to controls (n = 1,803) on age, treatment, and prostate cancer family history. Phospholipid fatty acids were extracted from serum, and concentrations of ω-3, ω-6, and trans-fatty acids (TFAs) were expressed as proportions of the total. Logistic regression models estimated odds ratios and 95% confidence intervals of associations of fatty acids with prostate cancer by grade. No fatty acids were associated with low-grade prostate cancer risk. Docosahexaenoic acid was positively associated with high-grade disease (quartile 4 vs. 1: odds ratio (OR) = 2.50, 95% confidence interval (CI): 1.34, 4.65); TFA 18:1 and TFA 18:2 were linearly and inversely associated with risk of high-grade prostate cancer (quartile 4 vs. 1: TFA 18:1, OR = 0.55, 95% CI: 0.30, 0.98; TFA 18:2, OR = 0.48, 95% CI: 0.27, 0.84). The study findings are contrary to those expected from the pro- and antiinflammatory effects of these fatty acids and suggest a greater complexity of effects of these nutrients with regard to prostate cancer risk.

Mechanisms of the anti-cancer and anti-inflammatory actions of vitamin D

Calcitriol, the hormonally active form of vitamin D, is being evaluated in clinical trials as an anti-cancer agent. Calcitriol exerts multiple anti-proliferative, pro-apoptotic, and pro-differentiating actions on various malignant cells and retards tumor growth in animal models of cancer. Calcitriol also exhibits several anti-inflammatory effects including suppression of prostaglandin (PG) action, inhibition of p38 stress kinase signaling, and the subsequent production of pro-inflammatory cytokines and inhibition of NF-κB signaling. Calcitriol also decreases the expression of aromatase, the enzyme that catalyzes estrogen synthesis in breast cancer, both by a direct transcriptional repression and indirectly by reducing PGs, which are major stimulators of aromatase transcription. Other important effects include the suppression of tumor angiogenesis, invasion, and metastasis. These calcitriol actions provide a basis for its potential use in cancer therapy and chemoprevention. We summarize the status of trials involving calcitriol and its analogs, used alone or in combination with known anti-cancer agents.

Optimization of the balanced steady state free precession (bSSFP) pulse sequence for magnetic resonance imaging of the mouse prostate at 3T

INTRODUCTION

MRI can be used to non-invasively monitor tumour growth and response to treatment in mouse models of prostate cancer, particularly for longitudinal studies of orthotopically-implanted models. We have optimized the balanced steady-state free precession (bSSFP) pulse sequence for mouse prostate imaging.

METHODS

Phase cycling, excitations, flip angle and receiver bandwidth parameters were optimized for signal to noise ratio and contrast to noise ratio of the prostate. The optimized bSSFP sequence was compared to T1- and T2-weighted spin echo sequences.

RESULTS

SNR and CNR increased with flip angle. As bandwidth increased, SNR, CNR and artifacts such as chemical shift decreased. The final optimized sequence was 4 PC, 2 NEX, FA 50°, BW ±62.5 kHz and took 14-26 minutes with 200 µm isotropic resolution. The SNR efficiency of the bSSFP images was higher than for T1WSE and T2WSE. CNR was highest for T1WSE, followed closely by bSSFP, with the T2WSE having the lowest CNR. With the bSSFP images the whole body and organs of interest including renal, iliac, inguinal and popliteal lymph nodes were visible.

CONCLUSION

We were able to obtain fast, high-resolution, high CNR images of the healthy mouse prostate with an optimized bSSFP sequence.

Melatonin, a novel Sirt1 inhibitor, imparts antiproliferative effects against prostate cancer in vitro in culture and in vivo in TRAMP model

We recently demonstrated that Sirt1, a NAD(+) -dependent histone deacetylase, was overexpressed in prostate cancer (PCa) and its inhibition resulted in a significant antiproliferative response in human PCa cells. Studies have suggested a link between Sirt1 and circadian rhythms, the disruption of which has been linked to cancer. Interestingly, a decreased production of the pineal melatonin has been shown to deregulate the circadian rhythm machinery and increase cancer risk. Furthermore, disruption in melatonin production and circadian rhythmicity has been associated with aging. Here, we challenged our hypothesis that melatonin will impart antiproliferative response against PCa via inhibiting Sirt1. We demonstrated that melatonin significantly inhibited Sirt1 protein and activity in vitro in multiple human PCa cell lines, and melatonin-mediated Sirt1 inhibition was accompanied with a significant decrease in the proliferative potential of PCa cells, but not of normal cells. Forced overexpression of Sirt1 partially rescued the PCa cells from melatonin's antiproliferative effects, suggesting that Sirt1 is a direct target of melatonin. Employing transgenic adenocarcinoma of mouse prostate (TRAMP) mice, we also demonstrated that oral administration of melatonin, at human-achievable doses, significantly inhibited PCa tumorigenesis as shown by decreases in (i) prostate and genitourinary weight, (ii) serum insulin-like growth factor-1 (IGF-1)/IGF-binding protein-3 (IGFBP3) ratio, (iii) mRNA and protein levels of the proliferation markers (PCNA, Ki-67). This anti-PCa response was accompanied with a significant decrease in Sirt1 in TRAMP prostate. Our data identified melatonin as a novel inhibitor of Sirt1 and suggest that melatonin can inhibit PCa growth via Sirt1 inhibition.

Long-term aspirin use and the risk of total, high-grade, regionally advanced and lethal prostate cancer in a prospective cohort of health professionals, 1988-2006

Experimental studies suggest a role for aspirin in the chemoprevention of prostate cancer and epidemiological evidence supports a modest inverse association between regular aspirin use and prostate cancer risk, especially for advanced disease. In a prospective cohort study of 51,529 health professionals aged 40-75 years at baseline, we evaluated long-term aspirin use and the incidence of total, high-grade (Gleason 8-10, n = 488), regionally advanced (T3b-T4 or N1, n = 228) and lethal prostate cancer (M1, bony metastases or prostate cancer death, n = 580) from 1988-2006. We used Cox proportional hazards regression to evaluate risk associated with frequency (days/week), quantity (tablets/week), recency and duration of aspirin use after multivariable adjustment for confounders and other predictors of prostate cancer risk. A total of 4,858 men were diagnosed with prostate cancer during the 18-year study period. Men taking ≥ 2 adult-strength aspirin tablets a week had a 10% lower risk of prostate cancer (p-for-trend = 0.02). For regionally advanced cancer, we observed no significant associations with aspirin use. For high-grade and lethal disease, men taking ≥ 6 adult-strength tablets/week experienced similar reductions in risk hazard ratio [HR = 0.72 (95% confidence intervals [CI]: 0.54, 0.96) and HR = 0.71 (95% CI: 0.50, 1.00)]. Analytical approaches to address bias from more frequent prostate-specific antigen screening among aspirin users did not yield different conclusions. We observed reductions in the risk of high-grade and lethal prostate cancer associated with higher doses of aspirin, but not with greater frequency or duration, in a large, prospective cohort of health professionals. Our data support earlier observations of modest inverse associations with advanced prostate cancer.

Regulation of NF-E2-related factor 2 signaling for cancer chemoprevention: antioxidant coupled with antiinflammatory

Cancer chemoprevention is a process of using either natural or synthetic compounds to reduce the risk of developing cancer. Observations that NF-E2-related factor 2 (Nrf2)-deficient mice lack response to some chemopreventive agents point to the important role of Nrf2 in chemoprevention. Nrf2 is a member of basic-leucine zipper transcription factor family and has been shown to regulate gene expression by binding to a response element, antioxidant responsive element. It is generally believed that activation of Nrf2 signaling is an adaptive response to the environmental and endogenous stresses. Under homeostatic conditions, Nrf2 is suppressed by association with Kelch-like ECH-associated protein 1 (Keap1), but is stimulated upon exposure to oxidative or electrophilic stress. Once activated, Nrf2 translocates into nuclei and upregulates a group of genes that act in concert to combat oxidative stress. Nrf2 is also shown to have protective function against inflammation, a pathological process that could contribute to carcinogenesis. In this review, we will discuss the current progress in the study of Nrf2 signaling, in particular, the mechanisms of Nrf2 activation by chemopreventive agents. We will also discuss some of the potential caveats of Nrf2 in cancer treatment and future opportunity and challenges on regulation of Nrf2-mediated antioxidant and antiinflammatory signaling in the context of cancer prevention.

Preclinical evaluation of a gene therapy treatment for transitional cell carcinoma

Three drugs were compared for their efficacy in treating murine transitional cell carcinoma (TCC) of the bladder. Intravesical gene therapy treatments utilizing expression-targeted plasmids, where the murine cyclooxygenase-2 (Cox-2) promoter was used to drive the expression of exogenously inducible forms of caspases 3 and 9, were compared with treatment modalities employing Bacille Calmette-Guérin (BCG) and celecoxib. When administered via lavage, only the gene therapy regimen was found to be effective at restricting tumor progression following a 7-day incubation of tumor tissues. Celecoxib was also administered via the diet to allow for systemic delivery of the drug. The most efficacious celecoxib use tested yielded tumors with masses of (18.3±8.4 mg) versus the gene delivery method, which yielded tumors with masses of (3.6±7.7 mg). The difference was significant (t-test, n≥4, P<0.025). The results showed that the Cox-2 expression-targeted gene therapy system could efficiently bypass the bladder permeability barrier and more effectively inhibit tumor growth and development than either BCG or celecoxib treatments. Long-term data further demonstrated that the gene therapy system could effectively inhibit tumor growth and elongate life expectancy.

cPLA2 is protective against COX inhibitor-induced intestinal damage

Cytosolic phospholipase A(2) (cPLA(2)) is the rate-limiting enzyme responsible for the generation of prostaglandins (PGs), which are bioactive lipids that play critical roles in maintaining gastrointestinal (GI) homeostasis. There has been a long-standing association between administration of cyclooxygenase (COX) inhibitors and GI toxicity. GI injury is thought to be induced by suppressed production of GI-protective PGs as well as direct injury to enterocytes. The present study sought to determine how pan-suppression of PG production via a genetic deletion of cPLA(2) impacts the susceptibility to COX inhibitor-induced GI injury. A panel of COX inhibitors including celecoxib, rofecoxib, sulindac, and aspirin were administered via diet to cPLA(2)(-/-) and cPLA(2)(+/+) littermates. Administration of celecoxib, rofecoxib, and sulindac, but not aspirin, resulted in acute lethality (within 2 weeks) in cPLA(2)(-/-) mice, but not in wild-type littermates. Histomorphological analysis revealed severe GI damage following celecoxib exposure associated with acute bacteremia and sepsis. Intestinal PG levels were reduced equivalently in both genotypes following celecoxib exposure, indicating that PG production was not likely responsible for the differential sensitivity. Gene expression profiling in the small intestines of mice identified drug-related changes among a panel of genes including those involved in mitochondrial function in cPLA(2)(-/-) mice. Further analysis of enterocytic mitochondria showed abnormal morphology as well as impaired ATP production in the intestines from celecoxib-exposed cPLA(2)(-/-) mice. Our data demonstrate that cPLA(2) appears to be an important component in conferring protection against COX inhibitor-induced enteropathy, which may be mediated through affects on enterocytic mitochondria.