Chemoprevention Of Bladder Cancer Research Articles

Omega-3 polyunsaturated fatty acids: a modified approach for chemo-prevention of bladder cancer in a rat model and molecular studies of antineoplastic mechanisms

To test the chemo-preventative effects of omega-3 against bladder cancer (BC) induction in a rat model and its potential antineoplastic mechanisms. Ninety male Fisher rats were divided into three groups during a 22-week protocol: group 1 (control), group 2 (Placebo + N-butyl-N-4- hydroxybutyl nitrosamine (BBN) for induction of BC and group 3 received omega-3 (1200mg/kg/day) + BBN. At the end, blood samples and bladder tissues were collected and checked for the presence of malignancy, markers of angiogenesis (VEGF relative gene expression), inflammation (IL-6), proliferation (KI-67 expressions), oxidative stress (serum MDA and serum SOD) and epigenetic control (miRNA-145 level). At the end of the study, 60% and 86.6% rats survived in group 2 and 3 with significant weight loss among rats in group 2 when compared with other groups. In group 2, all rats developed visible bladder lesions of which five and 13 developed squamous cell carcinoma (SCC) and transitional cell carcinoma (TCC). In omega3-treated group, only one developed low grade SCC and one developed high grade non- invasive TCC. Bladders from omega-3-treated rats showed lower expression ofKI-67 (p < 0.05), VEGF (p < 0.001) and IL-6 (p < 0.001) and significant higher expression of mi-RNA (p < 0.001). Also, omega-3-treated group showed statistically significant lower MDA level (p < 0.001). Omega-3 inhibits bladder tumor growth in the BBN-induced BC rat model, due to anti-inflammatory, antioxidant, anti-proliferative, and anti-angiogenic properties together with epigenetic control.

Vitamin A and Retinoids in Bladder Cancer Chemoprevention and Treatment: A Narrative Review of Current Evidence, Challenges and Future Prospects.

Bladder cancer (BC) is the tenth most common cancer worldwide with a high recurrence rate, morbidity and mortality. Therefore, chemoprevention and improved treatment of BC are of paramount importance. Epidemiological studies suggest that adequate vitamin A intake may be associated with reduced BC risk. In addition, retinoids, natural and synthetic derivatives of vitamin A, are intensively studied in cancer research due to their antioxidant properties and their ability to regulate cell growth, differentiation, and apoptosis. Findings from in vivo and in vitro models of BC show great potential for the use of retinoids in the chemoprevention and treatment of BC. However, translation to the clinical practice is limited. In this narrative review we discuss: (i) vitamin A and retinoid metabolism and retinoic acid signalling, (ii) the pathobiology of BC and the need for chemoprevention, (iii) the epidemiological evidence for the role of dietary vitamin A in BC, (iv) mechanistic insights obtained from in vivo and in vitro models, (v) clinical trials of retinoids and the limitations of retinoid use, (vi) novel systems of retinoid delivery, and (vii) components of retinoid signalling pathways as potential novel therapeutic targets.

Bladder Cancer Chemopreventive Agents: Current Knowledge and Concepts.

Bladder cancer is the most prevalent malignancy of the urinary tract and is associated with significant morbidity and mortality. Preventative efforts to reduce the medical and financial burdens of bladder cancer are highly desirable. However, the utilization of natural and pharmaceutical products for the prevention and treatment of bladder cancer remains largely controversial. Herein, we review the current body of evidence surrounding a number of natural dietary substances and their roles in chemoprevention of bladder cancer. Possible chemopreventative properties of several pharmaceutical agents are also reviewed. Overall, the current body of evidence is insufficient to establish a clear link between these proposed chemopreventive agents and risk of bladder cancer.

Targeting Inflammation for Bladder Cancer Chemoprevention

Cancer of the bladder is a serious health problem with significant mortality once it progresses to advanced stages. Moreover, chronic surveillance and treatments are required to prevent the inherent high recurrence and aggressive nature of these tumors. As a result, not only the quality of life for the patients is affected but it also adds to the treatment cost, making it one of the costliest cancers to treat. Therefore, it is highly imperative to consider preventive options that have been largely neglected. Although smoking prevalence is decreasing, a decline in BC incidence has not been seen, yet suggesting that smoking history and other factors still pose a threat to develop BC. With the increase of diabetic and obese populations, the risk for BC is also increasing. In spite of their modifiable nature, advancement in diagnosis, understanding of the disease, and enormous preclinical chemoprevention data, efforts in that direction for screening and primary or secondary prevention of this disease have been unsatisfactory. Moreover, no new therapeutic were approved for the last three decades; thus, the 5-year survival of BC patients has also not improved for decades. In the current review, we have discussed the central role of inflammation in the major risk factors such as smoking, diabetes, obesity, and infection leading to BC. We summarized the preclinical data of promising anti-inflammatory agents for primary, secondary, as well as tertiary prevention. Thus, we believe that developing chemopreventive strategies for bladder cancer by targeting inflammation is highly desirable.

Sulforaphane for the chemoprevention of bladder cancer: molecular mechanism targeted approach.

The clinical course for both early and late stage Bladder Cancer (BC) continues to be characterized by significant patient burden due to numerous occurrences and recurrences requiring frequent surveillance strategies, intravesical drug therapies, and even more aggressive treatments in patients with locally advanced or metastatic disease. For these reasons, BC is also the most expensive cancer to treat. Fortunately, BC offers an excellent platform for chemoprevention interventions with potential to optimize the systemic and local exposure of promising agents to the bladder mucosa. However, other than smoking cessation, there is a paucity of research that systematically examines agents for chemoprevention of bladder cancers. Adopting a systematic, molecular-mechanism based approach, the goal of this review is to summarize epidemiological, in vitro, and preclinical studies, including data regarding the safety, bioavailability, and efficacy of agents evaluated for bladder cancer chemoprevention. Based on the available studies, phytochemicals, specifically isothiocyanates such as sulforaphane, present in Brassicaceae or “cruciferous” vegetables in the precursor form of glucoraphanin are: (a) available in standardized formulations; (b) bioavailable- both systemically and in the bladder; (c) observed to be potent inhibitors of BC carcinogenesis through multiple mechanisms; and (d) without toxicities at these doses. Based on available evidence from epidemiological, in vitro, preclinical, and early phase trials, phytochemicals, specifically isothiocyanates (ITCs) such as sulforaphane (SFN) represent a promising potential chemopreventitive agent in bladder cancer.

Spray Dried Chitosan Microparticles for Intravesical Delivery of Celecoxib: Preparation and Characterization

Chitosan microparticles containing celecoxib (CB), were developed as chemoprevention of bladder cancer. Furthermore two inclusion complexes of CB with methyl-β-cyclodextrin (C1 and C2) were prepared to improve the solubility of the drug. C1 and C2 were obtained by freeze-drying and characterized in the solid state and in solution. Microparticles loaded with CB or C1 or C2 were prepared by spray drying and fully characterized. The yield and encapsulation efficiencies of microparticles depended by both the viscosity and the presence of the inclusion complex in the feed medium nebulised. Generally, the microparticles exhibited a spherical shape with mean diameter of approximately 2μm which was compatible with local intravesical administration using a catheter. The CB release studies from the microparticles allowed us to identify both immediate release systems (microparticles including the complexes) and prolonged release systems (microparticles including CB alone). The latter exhibited good adhesion to the bladder mucosa, as highlighted by a mucoadhesion study. Histological studies revealed a desquamation of the superficial cells when the bladder mucosa was treated with microparticles loaded with CB, while the morphology of the urothelium did not change when it was treated with microparticles loaded with the inclusion complex. A new CB intravesical formulation than can easily be administered with a catheter and is able to release the drug at the target site for several hours was realized. This new delivery system could be a good alternative to classic oral CB administration.

Inhibition of Bladder Tumor Growth by Chitooligosaccharides in an Experimental Carcinogenesis Model

Urinary bladder cancer is one of the most common cancers worldwide, with the highest incidence in industrialized countries. Patients with cancer commonly use unconventional and complementary therapy including nutraceuticals. In this study we evaluated the efficacy of chitooligosaccharides (in orange juice) in rat bladder cancer chemoprevention and as therapeutic agent, on a rat model of urinary bladder carcinogenesis induced with N-butyl-N-(4-hydroxybutyl) nitrosamine. Results indicate that chitooligosaccharides may have a preventive effect on bladder cancer development and a curative effect upon established bladder tumors, dependent on the concentration ingested 500 mg/kg b.w., every three days, showed capacity to inhibit and prevent the proliferation of bladder cancer; however, this was associated with secondary effects such as hypercholesterolemia and hypertriglyceridemia. The use of lower doses (50 and 250 mg/kg b.w.) showed only therapeutic effects. It is further suggested that this antitumor effect might be due to its expected anti-inflammatory action, as well as by mechanisms not directly dependent of COX-2 inhibition, such as cellular proliferation control and improvement in antioxidant profile.

Arctigenin Anti‐Tumor Activity in Bladder Cancer T24 Cell Line Through Induction of Cell‐Cycle Arrest and Apoptosis

Bladder cancer is the most common neoplasm in the urinary system. This study assesses arctigenin anti-tumor activity in human bladder cancer T24 cells in vitro and the underlying molecular events. The flow cytometry analysis was used to detect cell-cycle distribution and apoptosis. Western blotting was used to detect changes in protein expression. The data showed that arctigenin treatment reduced viability of bladder cancer T24 cells in a dose- and time-dependent manner after treatment with arctigenin (10, 20, 40, 80, and 100 μmol/L) for 24 hr and 48 hr. Arctigenin treatment clearly arrested tumor cells in the G1 phase of the cell cycle. Apoptosis was detected by hoechst stain and flow cytometry after Annexin-V-FITC/PI double staining. Early and late apoptotic cells were accounted for 2.32-7.01% and 3.07-7.35%, respectively. At the molecular level, arctigenin treatment decreased cyclin D1 expression, whereas CDK4 and CDK6 expression levels were unaffected. Moreover, arctigenin selectively altered the phosphorylation of members of the MAPK superfamily, decreasing phosphorylation of ERK1/2 and activated phosphorylation of p38 significantly in a dose-dependent manner. These results suggest that arctigenin may inhibit cell viability and induce apoptosis by direct activation of the mitochondrial pathway, and the mitogen-activated protein kinase pathway may play an important role in the anti-tumor effect of arctigenin. The data from the current study demonstrate the usefulness of arctigenin in bladder cancer T24 cells, which should further be evaluated in vivo before translation into clinical trials for the chemoprevention of bladder cancer.

Abstract 618: Rhodiola rosea L. extract, SHR-5, and metformin exhibit potent activity against bladder carcinogenesis in the UPII-mutant Ha-ras transgenic model.

Abstract The incidence of human urinary bladder cancer increases markedly with age, suggesting a mechanistic connection between aging and bladder carcinogenesis and a potential use of anti-aging agents in bladder cancer chemoprevention. Rhodiola rosea, growing in high altitude or cold regions of the world, has been reported to have anti-aging effects in Drosophila. Metformin, a popular anti-diabetics drug, has also shown anti-aging effect in mice. In addition, both agents have been shown to inhibit the mTOR pathway. Therefore, we examined the effect of SHR-5 and Metformin on bladder carcinogenesis in the UPII-mutant Ha-ras transgenic mouse bladder model. This model mimics human papillary transitional cell carcinoma and exhibits enhanced mTOR activity in the bladder tumors. The homozygous mutant Ha-ras transgenic mice were identified through genotyping using Southern blotting analysis. 0.625% SHR-5 or 0.1% Metformin in drinking water was given to the mice starting at 6 weeks of age and ending at 6 months of age. About 42% of homozygous mutant Ha-ras male transgenic mice which drank normal water died of urinary tract obstruction and hydronephrosis within 6 months of age, while more than 93% and 89% of mice which drank SHR-5 or Metformin containing water survived. The mean bladder weights in male mice drinking SHR-5 or Metformin decreased by 69% and 62%, respectively, compared to control group (Bladder weights for mice drinking normal water versus SHR-5 or Metformin are 0.3382± 0.061versus 0.1278± 0.02 or 0.1053±0.015 gram, P=0.0197 or 0.0082). The mean bladder weights in female mice which drank SHR-5 or Metformin containing water also decreased by about 40% or 39.8 %, respectively, compared to those which drank normal water (Bladder weights for normal water versus SHR-5 or Metformin: 0.07149 ±0.0036 versus 0.04301 ±0.0032 or 0.04295±0.0115 gram, P&amp;lt;0.0001 or =0.0007). Chemstrip tests showed that mice which drank SHR-5 or metformin water developed less hematurine than those which drank normal water. Histological analysis of H&amp;E staining bladder sections from SHR-5 and Metformin treated mice demonstrated more differentiated tumors compared to those from the transgenic mice which drank normal water. Immunohistochemistry staining revealed that SHR-5 and Metformin treatments decreased cell proliferation in the urothelium. Taken together, our results suggest a potential new method for bladder cancer prevention by drinking SHR-5 or Metformin. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 618. doi:1538-7445.AM2012-618

Abstract 620: Chemoprevention of hydroxybutyl(butyl)nitrosamine (OH-BBN)-induced mouse urinary bladder cancer by the kava chalcone flavokawain A

Abstract About 75% of human bladder cancers are associated with cigarette smoking or exposure to industrial carcinogens. Kava roots have been traditionally used to prepare beverage and herb medicine in the South Pacific Island nations (Fiji, Vanutu, Samoa, etc.) for thousands of years. Recently, an epidemiological study has linked high kava consumption to lower incidences of cancers, including lung and bladder cancers, despite the presence of many smokers in the populations of the South Pacific Islands. We therefore examined the potential of flavokawain A, a predominant chalcone isolated from the kava plant for prevention of mouse urinary bladder cancer induced by the organ-specific and tobacco-smoking related nitrosamine OH-BBN. B6D2F1 mice at 8 weeks of age were gavaged 7.5 mg OH-BBN once per week for 12 weeks. In the standard prevention protocol, 0.1% FKA or vehicle food was administered as a dietary supplement to each group of mice beginning 1 week before the first OH-BBN administration and ending 32 weeks after the initial OH-BBN treatment. Dietary feeding of OH-BBN treated mice with 0.1% flavokawain A in the mouse diet decreased bladder wet weight by about 57% (Bladder weights for control versus flavokawain A were 74.18 ± 16.7 versus 32 ± 1.5 mg; P&amp;lt;0.01). In the standard promotion protocol, 0.1% FKA or vehicle food was given 1 week after the final OH-BBN administration for 19 weeks. Flavokawain A also significant reduced the bladder wet weight by about 27% (Bladder weights for control versus flavokawain A were 89.4 ± 23.4 versus 65.5 ± 10.6 mg; p&amp;lt;0.05). To increase the incidence of palpable OH-BBN induced bladder tumors, we extended 7.5mg OH-BBN treatment once per week for one more week up to a total of 13 weeks. In this modified promotion protocol, the percentage of palpable tumors in control group has reached to about 53%, which is similar to that reported by published literatures. Dietary feeding of 0.6% flavokawain A significantly decrease bladder wet weight by 73% (Bladder weights for control versus flavokawain A were 314.9 ± 106.7 versus 87.3 ± 15.2 mg, p=0.0265). In addition, we showed that flavokawain A induced activities of phase II enzyme (i.e. glutathione S-transferase and quinone reductase) in different organs (bladder, liver, prostate, etc.) of mice. Taken together, these results suggest that flavokawain A deserves further investigation for bladder cancer chemoprevention by targeting smoking or carcinogens exposed populations. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 620. doi:1538-7445.AM2012-620

Rhodiola rosea extracts and salidroside decrease the growth of bladder cancer cell lines via inhibition of the mTOR pathway and induction of autophagy

The incidence of human urinary bladder cancer increases markedly with age, suggesting a mechanistic connection between aging and bladder carcinogenesis and a potential use of anti-aging agents in bladder cancer chemoprevention. Rhodiola rosea, growing in high altitude or cold regions of the world, has been reported to have anti-aging effects in Drosophila. We demonstrated that a R. rosea extract and one of its bioactive components, salidroside, inhibited the growth of bladder cancer cell lines with a minimal effect on nonmalignant bladder epithelial cells TEU-2. Interestingly, the R. rosea extract and salidroside component exhibited a selective ability to inhibit the growth of p53 knockout primary mouse embryo fibroblasts (p53-/- MEFs) compared to their wild-type counterparts. The growth inhibitory effects of the R. rosea extract and salidroside were, however, attenuated in TSC2 and p53 double knock MEFs (TSC2-/-, p53-/- MEFs), suggesting that TSC2 protein is, at least in part, required for the growth inhibitory effects of the R. rosea extract and salidroside. The R. rosea extract and salidroside treatment of UMUC3 cells resulted in an increase of AMP-activated protein kinase (AMPK)-α phosphorylation and a decrease of 4E-BP1 phosphorylation, leading to increased binding of 4E-BP1 to m7 GTP. These results indicate that the R. rosea extract and salidroside inhibit translation initiation. Furthermore, both the R. rosea extract and salidroside treatment of UMUC3 cells caused a significant percentage of cells undergoing autophagy. Therefore, the R. rosea extract and salidroside deserve further study as novel agents for chemoprevention of bladder carcinogenesis.

Pathobiology and Chemoprevention of Bladder Cancer

Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.

Abstract 3799: Rhodiola rosea extracts, salidroside, and metformin decrease the growth of bladder cancer cell lines via inhibition of TSC- mediated translation initiation and induction of autophagy

Abstract Bladder cancer well illustrates the association between aging and cancer, with over 71% of first diagnoses and 85.5% of deaths occurring in patients after 65 years of age. Since cancer and aging share a number of disruptions in molecular pathways and regulatory mechanisms, we examined whether agents with potential anti-aging properties could be useful in bladder cancer chemoprevention. Rhodiola rosea has been in use for centuries in many traditional medicinal practices to increase physical and mental performances, and Rhodiola rosea extracts (RRE) has been the agent in many clinical studies with no reported side effects or drug interactions. Metformin, a commonly prescribed oral and well-tolerated antidiabetic drug, is an insulin-sensitizer. Both RRE and metformin have been reported to have anti-aging effects in model organisms such as Drosophila. In bladder cancer prevention studies, we demonstrated that RRE, one of its active components, salidroside, or metformin significantly inhibit the growth of human urinary bladder cancer cell lines (including RT4, 5637, UMUC3, T24, HT1376, TCCSUP, J82, 253J-P, 253J-BV and 5637), with a minimal effect on normal bladder epithelial cells (TEU-2). In addition, RRE, salidroside and metformin are more effective in the reduction of colony formation of UMUC3 cells in soft agar than in two dimension culture, which suggests their potentials for inhibiting in vivo tumor growth. Using the primary mouse embryo fibroblasts tuberous sclerosis (TSC)-1 or TSC2 knockout and wild-type cells, we showed that TSC2 protein was, at least in part, required for the growth inhibitory effect of RRE, salidroside and metformin. Further study showed that RRE, salidroside and metformin reduce the phosphorylation of the S6 kinase and 4EBP1 which increase the binding of 4EBP1 to m7GTP to stop translation initiation in TSC-positive. UMUC3 but not in TSC-negative RT4 cells. In UMUC3 cells with stably overexperessed EGFP-LC3, we also observed that RRE, salidroside and metformin all significantly increase the percentage of cells with punctuate EGFP-LC3 fluorescence within four to eight hours of treatment, suggesting induction of autophagy. The autophagysome formation by these treatments was further confirmed by vital staining with acridine orange and western blotting analysis of LC3-II cleavage. In summary, our results indicate that RRE, salidroside and metformin share some similar molecular mechanisms in their anti-bladder cancer activity in vitro by involvement of TSC tumor suppressors-mediated inhibition of translational initiation, and by induction of autophagy. Further animal experiments are needed to examine the comparative efficacy of these agents in chemoprevention of bladder carcinogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3799.

Abstract 5678: Kavalactone yangonin induces autophagy, inhibits TSC-mediated translation initiation and acts synergistically with a kava chalcone flavokawain A on growth inhibition in bladder cancer UMUC-3 cells

Abstract Autophagy is a tightly regulated lysosomal self-digestion process that has been shown to suppress primary tumor formation. However, the mechanisms and potential usefulness of autophagy induction in cancer prevention remain controversial and largely unknown. To facilitate the study of the potential of autophagy induction as a mechanism for bladder cancer prevention, we have established a bladder cancer cell line with a stably over-expressed EGFP-LC3 gene (a hallmark gene for autophagy). Using this cell line, we screened out kavalactones yangonin and dehydrokawain as strong autophagy inducers in bladder cancer cells, but not the previously defined apoptosis inducers flavokawains also found in kava root extracts. Yangonin treatment at concentrations of 1.25 to 50 μg/ml for eight hours significantly increases the percentage of EGFP-LC3 cells with punctuate EGFP-LC3 fluorescence up to 80%. The induction of autophagy by yangonin treatment was further confirmed by electron microscopy observation of increased autolysosome formation and by western blotting analysis of LC3-II cleavage. The effect of yangonin on autophagy induction corresponds to its anchorage-dependent and independent growth inhibitory effect in a dose and time dependent manner in UM-UC-3 cells. Similarly, yangonin also induces autophagy and inhibits cell growth in another bladder cancer cell line T24. Further study demonstrated that yangonin is less effective in reducing the cell viability of the primary mouse embryo fibroblasts tuberous sclerosis-1 knockout (MEF TSC1−/−) than that of wild-type cells (MEF TSC1+/+) cells. This result suggested that TSC1 may be, at least in part, required for the growth inhibitory effect of yangonin. Immunoprecipitation experiments showed an increased formation of the TSC1/TSC2 immunocomplex after yangonin treatment in UMUC-3 cells. In addition, yangonin treatment of UMUC-3 cells resulted in a decrease in phosphorylation of mTOR and 4E-BP1 with subsequent increased binding of 4E-BP1 to m7GTP, which is responsible for stoppage of translational initiation. Interestingly, yangonin in combination with flavokawain A, an apoptosis inducer, synergistically inhibits the growth of UMUC-3 cells. Taken together, our results may suggest a novel strategy for bladder cancer chemoprevention through combination of autophagy and apoptosis inducers, yangonin and flavokawain A. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5678.

P38 MAPK plays a distinct role in sulforaphane-induced up-regulation of ARE-dependent enzymes and down-regulation of COX-2 in human bladder cancer cells

Sulforaphane, a well-characterised dietary isothiocyanate, has been demonstrated to be a potent anti-carcinogenic agent in numerous cancer models, including in bladder cancer cells. In the present study, sulforaphane up-regulated the expression of two Nrf2-dependent enzymes, glutathione transferase (GSTA1-1) and thioredoxin reductase (TR-1), and down-regulated cyclooxygenase 2 (COX-2) in human bladder cancer T24 cells. This action of sulforaphane was associated with the p38 MAPK activity. When a specific p38 MAPK inhibitor, SB202190, was used, both sulforaphane-induced up-regulation of GSTA1-1 and TR-1 and down-regulation of COX-2 were eliminated; in contrast, an activator of p38 MAPK, anisomycin, enhanced the effect of sulforaphane on modulation of GST, TR-1 and COX-2 expression. Moreover, it was established that anisomycin increased nuclear translocation of Nrf2, whereas SB202190 abrogated sulforaphane-induced Nrf2 translocation into the nucleus. In summary, these data suggest that p38 MAPK activation can regulate Nrf2-antioxidant response element (ARE)-driven enzymes and COX-2 expression, thereby facilitating the role of sulforaphane in cancer prevention. This study strongly supports the contention that p38 MAPK is a pivotal and efficient target of sulforaphane in the chemoprevention of bladder cancer.

Anti-inflammatory, anti-proliferative and antioxidant profiles of selective cyclooxygenase-2 inhibition as chemoprevention for rat bladder carcinogenesis

Purpose: To evaluate the efficacy of a selective cyclooxygenase-2 (COX-2) inhibitor in rat bladder cancer chemoprevention, as well as to assess the relevance of inflammation, proliferation and oxidative stress in tumour growth and in its prevention. Methods: Drug treatments were performed during the first 8 weeks, followed by 12 weeks for tumour expression/prevention, in the following groups: control – vehicle; carcinogen – 0.05% of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN); celecoxib (CEL) – 10 mg/kg/day and preventive CEL+BBN. The bladders were analysed for number and volume of tumour and nature of urothelium lesions. Serum was assessed for markers of inflammation, proliferation and redox status.Results: The main findings were: a) the incidence of carcinoma was: control: 0% (0/8); BBN: 65% (13/20); CEL: 0% (0/8) and BBN+CEL: 12.5% (1/8); b) the mean tumour volume per rat with tumour and per tumour were significantly lower in the BBN+CEL group (21.2 and 5.3±0.4 mm3) vs BBN (138.5±7.5 and 112.5±6.4 mm3); c) the incidence of pre-neoplasic (hyperplasia and dysplasia) and neoplasic (papillary tumours and carcinoma in situ - CIS) lesions were notoriously reduced in the CEL+BBN treatment; d) CEL significantly reduced serum TGF-β1 and CRP and increase TNF-α and IL-1β (P

Sulforaphane down-regulates COX-2 expression by activating p38 and inhibiting NF-κB-DNA-binding activity in human bladder T24 cells

Cyclooxygenase-2 (COX-2) overexpression has been associated with the grade, prognosis and recurrence of transitional cell carcinoma (TCC) of the bladder. In this study, sulforaphane, a dietary isothiocyanate, down-regulated COX-2 expression in human bladder transitional cancer T24 cells at both transcriptional- and translational levels. Sulforaphane (5-20 microM) induced nuclear translocation of NF-kappaB and reduced its binding to the COX-2 promoter, a key mechanism for suppressing COX-2 expression by sulforaphane. Moreover, sulforaphane increased expression of p38 and phosphorylated-p38 protein. A specific inhibitor of p38 MAPK, SB202190, was used to further investigate its pivotal role in sulforaphane-mediated down-regulation of COX-2. Exposure of T24 cells to SB202190 1 hour prior to sulforaphane treatment abolished the effect of sulforaphane on COX-2 mRNA down-regulation, but enhanced COX-2 transcription. Furthermore, SB202190 alone induced NF-kappaB translocation to the nucleus, promoted NF-kappaB binding to the COX-2 promoter and resulted in up-regulation of COX-2 expression. Taken together, these data suggest that p38 is essential in sulforaphane-mediated COX-2 suppression and provide new insights into the molecular mechanisms of sulforaphane in the chemoprevention of bladder cancer.

Effect of sulforaphane on cell growth, G0/G1 phase cell progression and apoptosis in human bladder cancer T24 cells

Isothiocyanates (ITCs) from cruciferous vegetables have been shown to be effective in blocking initiation as well as progression of a range of chemically-induced tumors in animal models. In this study, sulforaphane, the most extensively studied ITC, was found to suppress the growth of T24 bladder cancer cells in vitro in a dose-dependent manner. Sulforaphane inhibited the proliferation of T24 cells with IC(5)0 values 26.9 and 15.9 microM following 24 and 48 h treatments. Sulforaphane (5-20 microM) induced early apoptosis and blocked cell cycle progression at G(0)/G(1) phase which was associated with upregulation of cyclin-dependent kinase inhibitor p27 expression. These results support a role for sulforaphane as an effective agent in the chemoprevention of bladder cancer.

Use of selenium in chemoprevention of bladder cancer

The anticarcinogenic potential of selenium was first identified nearly 40 years ago in geographical studies that reported lower death rates for cancer in regions with high levels of selenium. Cancer of the bladder was one of the body sites found to share this inverse association. Although many subsequent studies have been done on selenium and cancer, only a few have specifically assessed the relation with bladder cancer. However, the high recurrence rate and ability to monitor bladder urothelial-cell carcinoma make selenium a good candidate for chemoprevention. Evidence suggests that selenium is a biologically plausible, safe, and efficacious potential chemoprevention agent for bladder cancer. Large tertiary chemoprevention trials are needed to further investigate the role of selenium in the prevention of bladder cancer. Future studies should assess the best dose and form of selenium, and whether the protective effect of selenium differs between the sexes.

Effect of an epidermal growth factor receptor tyrosine kinase inhibitor on actin remodeling in anin vitrobladder cancer carcinogenesis model

Alteration of actin remodeling is a marker of malignant-associated field defect and a potential surrogate biomarker for chemoprevention trials. We tested erlotinib, a specific tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR), on actin remodeling in a bladder carcinogenic model consisting of untransformed HUC-PC cells and transformed MC-T11 cells, both derived from the same normal human urothelial clone immortalized by SV40. Erlotinib had a selective growth inhibitory and actin remodeling effect on MC-T11 cells over HUC-PC cells, as examined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and immunofluorescence labeling with laser scan cytometer analysis, respectively. The IC(50) of untransformed HUC-PC cells was significantly higher than that of transformed MC-T11 cells (P < 0.05, t test). The actin remodeling effect was more prominent at lower dosage levels (1/8-1/4 of IC(50)), which was accompanied by an increased cell adhesion and decreased motility. At higher dosage levels (1/2 of IC(50)), erlotinib induced a decreased adhesion and anoikis (detachment-associated apoptosis). The transformed MC-T11, but not HUC-PC, showed a weak constitutive EGFR phosphorylation activity, which was inhibited by erlotinib in a dose-response manner. However, on epidermal growth factor stimulation, both cell lines showed a similar dose-response inhibitory effect on phosphorylated EGFR and mitogen-activated protein kinase (MAPK; P44/P42) activities, and MAPK inhibitor PD98059 showed no specific effect on erlotinib-induced actin remodeling, suggesting that pathways other than MAPK (P44/P42) may be responsible for erlotinib-induced actin remodeling. The findings provide evidence to support erlotinib-based bladder cancer chemoprevention and using actin remodeling as a marker for erlotinib-based intervention trials.