Effects of vitamin D (calcitriol) on transitional cell carcinoma of the bladder in vitro and in vivo

Integrated evaluation of workplace exposures and biomarkers of bladder cancer among textile dyeing workers

BACKGROUND

The textile industry is the second risk factor for bladder cancer, after smoking. Previous studies focused on the impact of exposure to high concentrations of bladder carcinogenic chemicals in the textile dyeing industry on the elevation of bladder cancer biomarkers. This study aimed to evaluate bladder carcinogenic air pollutants in a textile dyeing factory and investigate its role and the role of serum 25-hydroxyvitamin D (25-OH vit. D) on cancer bladder biomarkers in exposed workers.

METHODS

A cross-sectional study was conducted. Particulate and vapor forms of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) were monitored in the printing, dyeing, and preparing sections of a textile factory. Bladder tumor antigen (BTA), nuclear matrix protein 22 (NMP-22), and 25-OH vit. D were estimated in all the exposed workers (147 exposed workers) and in workers not occupationally exposed to chemicals (130 unexposed workers).

RESULTS

Aromatic bladder carcinogenic compounds were either in low concentrations or not detected in the air samples of working areas. BTA and NMP-22 of exposed workers were not significantly different from the unexposed. However, 25-OH vit. D was significantly lower in the exposed than unexposed workers. There was a significant inverse correlation between 25-OH vit. D and duration of exposure in exposed workers.

CONCLUSION

The mean levels of PAHs and VOCs were within the safe standard levels in the working areas. The non-significant difference in BTA and NMP-22 between the exposed and unexposed groups suggests the presence of occupational exposures to safe levels of bladder carcinogenic aromatics, while the significantly lower 25-OH vit. D levels among the exposed than the unexposed groups could suggest the potential association of 25-OH vit. D with occupational exposures to low levels of PAHs and VOCs, and this association was found to be inversely correlated with the duration of exposures. Accordingly, more specific predictor tests must be applied for early diagnosis of bladder cancer among the exposed workers.

Comparison of serum 25(OH) vitamin D, parathormone and immunity marker concentrations between dogs with transmissible venereal tumour and healthy dogs

BACKGROUND

1,25-Dihydroxyvitamin D (1,25(OH)2 D) is vital in the homeostasis of calcium and bone health as well as in the prevention of many disorders such as neoplasms. Epidemiological data show that low concentrations of both 1,25(OH)2 D and its precursor 25(OH) vitamin D (25(OH)D) are associated with an increased risk of a variety of human tumours.

OBJECTIVES

To investigate 25(OH)D, parathormone (PTH) and immunity marker concentrations in dogs with transmissible venereal tumour (TVT).

METHODS

25(OH)D, PTH and various biochemical and immunity markers were evaluated in dogs with TVT (n = 26) and in healthy (n = 30) dogs.

RESULTS

25(OH)D concentrations were significantly lower in dogs with TVT in comparison with healthy dogs. In contrast, PTH, immunoglobulin G and interleukin (IL)-9 concentrations were higher in the dogs with TVT. Other variables, including IL-10, interferon γ, calcium and inorganic phosphate, were not statistically different between the two groups.

CONCLUSIONS

Decreased serum 25(OH)D concentration may be a risk factor for the development of canine TVT; however, cause-and-effect remains incompletely understood. Further studies are required to elucidate the exact role of 25(OH)D in canine TVT and whether vitamin D supplementation may be useful prophylactically or as an adjunct to chemotherapy.

Vitamin D increases the efficacy of cisplatin on bladder cancer cell lines

BACKGROUND

1,25(OH)2D3(Calcitriol), which is a broad regulatory molecule, plays a role in changing the efficacy of chemotherapeutic drugs. Cisplatin is one of a current standard chemotherapy regimen for bladder cancer. Increasing the effectiveness of the treatment and reducing the side effects to chemotherapeutics are of great importance in bladder cancer. We aimed to investigate the effect of the combination of cisplatin and calcitriol in order to create a possible advantage in treatment of bladder cancer.

METHODS

T24, ECV-304 and HUVEC cell lines were treated with calcitriol and cisplatin individually and in combination. Dose determination and combination treatments of calcitriol and cisplatin were evaluated using the MTT assay for cytotoxicity analysis on the cells. Annexin V-PI staining method was used for apoptosis determination by flow cytometry. Also the P-gp expression levels were determined by flow cytometry.

RESULTS

The combination treatment increased the anti-proliferative efficacy compared to the efficacy in cisplatin alone in T24 cells and reduced the cytotoxicity in the HUVEC healthy cells compared to cisplatin alone. Combination treatment achieved significantly higher apoptosis rate in T24 cells compared with the rates in treatment of cisplatin alone. However apoptosis decreased in HUVEC cell line. P-gp ratios were increased in HUVEC and decreased in T24 cells with combination treatment compared to the numbers in the control cells. The rate of apoptosis and P-gp levels showed no significant change in ECV-304 cells.

CONCLUSION

Our study revealed that the combination of calcitriol and cisplatin allows the use of cisplatin at lower doses in T24 bladder cancer cell line.

Vitamin D and Vitamin D-binding protein and risk of bladder cancer: A nested case-control study in the Norwegian Janus Serum Bank Cohort

Background

 High circulating levels of vitamin D (25(OH)D) are suggested to reduce the risk of urinary bladder cancer (BC), but the evidence is weak, and several studies lack sufficient adjustment for potential confounders (e.g., smoking, body mass index (BMI), and physical activity). Moreover, few studies have investigated the role of vitamin D‐binding protein (DBP) in this context. We conducted a matched nested case–control study including 378 cases and 378 controls within the Norwegian population‐based Janus cohort, using serum collected 5–41 years prior to diagnosis, to study 25(OH)D and BC risk, by taking circulating DBP into account.

Methods

Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), for 25(OH)D, DBP, and the molar ratio of 25(OH)D:DBP, an estimate of unbound (free) 25(OH)D levels. We adjusted for smoking (status and pack‐years), BMI, physical activity, education and (mutually) for 25(OH)D and DBP. Restricted cubic splines were employed to examine nonlinear associations.

Results

High optimal levels of circulating 25(OH)D (≥100 nmol/L) (HR 0.35, 95% CI 0.19–0.64) were associated with decreased BC risk, when compared with insufficient concentrations (50–74 nmol/L). This association was less pronounced for optimal levels (75–99 nmol/L) (HR = 0.69, 95% CI 0.47–1.01). Moreover, estimated free 25(OH)D, was associated with decreased BC risk for molar ratio 17–21 (HR 0.66, 95% CI 0.44–0.97) and ≥22 (HR 0.50, 95% CI 0.29–0.82), compared to molar ratio 11–16. The HR function for BC risk was not linear, rather reversed u‐shaped, with the highest HR at 62.5 nmol/L and 13.5 molar ratio, respectively.

Conclusion

High levels of total and estimated free 25(OH)D were associated with reduced risk of BC, compared with insufficient concentrations. DBP was not associated with BC risk. We did not observe any impact of DBP or any of the studied lifestyle factors on the association between 25(OH)D and BC.

The Role of Steroid Hormone Receptors in Urothelial Tumorigenesis

Preclinical and/or clinical evidence has indicated a potential role of steroid hormone-mediated signaling pathways in the development of various neoplastic diseases, while precise mechanisms for the functions of specific receptors remain poorly understood. Specifically, in urothelial cancer where sex-related differences particularly in its incidence are noted, activation of sex hormone receptors, such as androgen receptor and estrogen receptor-β, has been associated with the induction of tumor development. More recently, glucocorticoid receptor has been implied to function as a suppressor of urothelial tumorigenesis. This article summarizes and discusses available data suggesting that steroid hormone receptors, including androgen receptor, estrogen receptor-α, estrogen receptor-β, glucocorticoid receptor, progesterone receptor and vitamin D receptor, as well as their related signals, contribute to modulating urothelial tumorigenesis.

Low Plasma 25-Hydoxyvitamin D at Diagnosis Predicts Poor Outcomes in Patients with Bladder Cancer: A Prospective Cohort Study

This study aimed to investigate whether plasma 25-hydroxyvitamin D (25-OHD) at diagnosis predicts poor outcomes in patients with urothelial bladder cancer. A total of 177 patients with non-muscle-invasive bladder cancer (NMIBC) were prospectively followed up over a period extending beyond 6 years. Data on poor outcomes (ie., recurrence, progression, and mortality) were collected. Plasma 25-OHD was measured by immunoassay. Cutoff-Finder web application was used to determine the best 25-OHD cutoff point to predict a specific poor outcome. Cox-hazard models were applied to test how plasma 25-OHD affect patients outcome while adjusting for potential confounding factors. During the follow-up period, tumor recurrence and progression occurred in 40.7% and 14.1% of patients, respectively and 11.3% of patients died. Baseline 25-OHD was lower in patients who experienced poor outcome (12.2 ± 7.44 vs. 16.7 ± 10.6 ng/mL; p < 0.001). Multi-adjusted HR (95% CI) for vitamin D deficiency (25-OHD < 12 ng/mL) was 2.09 (1.27-3.44) for recurrence, 2.63 (1.06-6.49) for progression and 2.93 (1.04-8.25) for mortality in patients with NMIBC. Low plasma 25-OHD in NMIBC patients is associated with higher risk of poor outcome. Future work is required to test whether correction of vitamin D deficiency will improve quality of life and extend survival in these patients.

Low serum 25-hydroxyvitamin D is associated with increased bladder cancer risk: A systematic review and evidence of a potential mechanism

The development of some cancers is associated with vitamin D deficiency. We suggest that reduced conversion of 25-hydroxyvitamin D (25(OH)D) to 1,25-dihydroxyvitamin D (1,25(OH)₂D) and the resulting modification of tissue specific immune responses may be key. Non-muscle-invasive bladder cancer is highly immunoresponsive and stimulation of an inflammatory response by intravesical bacillus Calmette-Guerin (BCG) treatment prevents recurrence. To assess the relationship between serum 25(OH)D and bladder cancer risk we conducted a systematic review. To test our hypothesis, the synthesis of 1,25(OH)₂D by human bladder epithelial cell lines (T24/83 and RT4) was examined. Studies were identified from Medline, Web of Science, Embase and Cochrane library (limited to English language, humans and 1990-2018). After removal of duplicates, title and abstract review 6 full papers were appraised. Low vitamin D levels were associated with bladder cancer risk in 5/6 of the studies. Both cell lines express the vitamin D receptor, 25-hydroxyvitamin D 1α-hydroxylase (1α-OHase) and 24-hydroxylase (24-OHase) mRNA, which was induced by 1,25(OH)₂D. 24-OHase mRNA was also increased by 25(OH)D indicating 1α-OHase activity. Both cell types expressed TLR1,2,4 and the TLR partners MyD88 and CD14mRNA. Cathelicidin mRNA was undetectable in both cell lines but was induced by 1,25(OH)₂D and 25(OH)D in RT4 cells. The systematic review demonstrated that bladder cancer risk correlates with serum 25(OH)D levels. In addition, we have shown that transitional epithelial cells express functional vitamin D signaling and can synthesize sufficient 1,25(OH)₂D to stimulate a local immune response. We suggest that in order to maintain optimal immune surveillance within the bladder adequate levels of serum 25(OH)D are required for direct synthesis of 1,25(OH)₂D by bladder epithelial cells.

Differential regulation of intestinal and hepatic CYP3A by 1α,25-dihydroxyvitamin D3 : Effects on in vivo oral absorption and disposition of buspirone in rats

1α,25-Dihydroxyvitamin D₃ (also called 1,25(OH)₂ D₃ or calcitriol) is the biologically active form of vitamin D, which functions as a ligand to the vitamin D receptor (VDR). It was previously reported that intestinal cytochrome P450 3A (CYP3A) expression was altered by 1,25(OH)₂ D₃ -mediated VDR activation. However, to clarify whether the change in CYP3A subfamily expression by VDR activation can affect metabolic function, further evidence is needed to prove the effect of 1,25(OH)₂ D₃ treatment on CYP3A-mediated drug metabolism and pharmacokinetics. Here, we report the effects of 1,25(OH)₂ D₃ on CYP3A activity and in vivo pharmacokinetics of buspirone in Sprague-Dawley rats. CYP3A mRNA expression and CYP3A-mediated testosterone metabolism were enhanced in the intestine but were unaffected in the livers of rats treated with 1,25(OH)₂ D₃ . Notably, the oral pharmacokinetic profile of buspirone (CYP3A substrate drug) and 6'-hydroxybuspirone (major active metabolite of buspirone formed via CYP3A-mediated metabolism) was significantly altered, while its intravenous pharmacokinetic profile was not affected by 1,25(OH)₂ D₃ treatment. To the best of our knowledge, this study provides the first reported data regarding the effects of 1,25(OH)₂ D₃ treatment on the in vivo pharmacokinetics of intravenous and oral buspirone in rats, by the differential modulation of hepatic and intestinal CYP3A activity. Our present results could lead to further studies in clinically significant CYP3A-mediated drug-nutrient interactions with 1,25(OH)₂ D₃ , including 1,25(OH)₂ D₃ -buspirone interaction. Preclinical Research & Development.

Circulating vitamin D in relation to cancer incidence and survival of the head and neck and oesophagus in the EPIC cohort

Experimental and epidemiological data suggest that vitamin D play a role in pathogenesis and progression of cancer, but prospective data on head and neck cancer (HNC) and oesophagus cancer are limited. The European Prospective Investigation into Cancer and Nutrition (EPIC) study recruited 385,747 participants with blood samples between 1992 and 2000. This analysis includes 497 case-control pairs of the head and neck and oesophagus, as well as 443 additional controls. Circulating 25(OH)D3 were measured in pre-diagnostic samples and evaluated in relation to HNC and oesophagus cancer risk and post-diagnosis all-cause mortality. After controlling for risk factors, a doubling of 25(OH)D3 was associated with 30% lower odds of HNC (OR 0.70, 95% confidence interval [95% CI] 0.56-0.88, Ptrend = 0.001). Subsequent analyses by anatomical sub-site indicated clear inverse associations with risk of larynx and hypopharynx cancer combined (OR 0.55, 95CI% 0.39-0.78) and oral cavity cancer (OR 0.60, 95CI% 0.42-0.87). Low 25(OH)D3 concentrations were also associated with higher risk of death from any cause among HNC cases. No clear association was seen with risk or survival for oesophageal cancer. Study participants with elevated circulating concentrations of 25(OH)D3 had decreased risk of HNC, as well as improved survival following diagnosis.

Targeted delivery of vitamin D3-loaded nanoparticles to C6 glioma cell line increased resistance to doxorubicin, epirubicin, and docetaxel in vitro

In recent years, targeted delivery systems have been used along with combinatorial therapy to decrease drug resistance and increase cancer therapy efficacy. The anti-proliferative effects of vitamin D3 (VD3) on cancerous cells, such as C6 glioma, with active hedgehog pathways raised the question as to whether pre-targeting C6 glioma cells with VD3-loaded nanoparticles (VD3NPs) can enhance the anti-tumor effects of doxorubicin, epirobicin, and docetaxel on this drug-resistant cell line. Here, studying at cellular, nuclear, protein, and gene levels we demonstrated that VD3NP-doxorubicin and VD3NP-epirobicin combinations increased the probability of chemotherapy/radiotherapy resistance and cancer stem cell (CSC) properties in C6 glioma significantly (P < 0.05), compared to doxorubicin and epirobicin alone. However, VD3NP-docetaxel combination may have the potential in sensitizing C6 cells to ionizing irradiation, but this combination also increased the CSC properties and the probability of drug resistance significantly (P < 0.05), compared to docetaxel alone. Although our previous study showed that targeted delivery of VD3 reduced the rate of proliferation significantly (P < 0.05) in C6 glioma cells (a drug-resistant cell line), here we concluded that combinatorial therapy of exogenous VD3 with doxorubicin, epirobicin, and docetaxel not only did not lead to the enhancement of cytotoxic effects of the aforementioned drugs but also increased the cancerous characteristics in C6 glioma, in vitro.

Vitamin D and urological cancers

Introduction

Vitamin D controls calcium and phosphate homeostasis. Additionally, it has been proven that vitamin D is an important modulator of cellular differentiation and proliferation in a number of normal and malignant cells. Vitamin D can regulate proliferation, apoptosis, and cell adhesion at the tumor cell level. It also modifies tumor angiogenesis, invasion, and metastasis and also decreases oxidative DNA damage.

Material and methods

The Medline and Web of Science databases were searched without time limit on October 2015 using the terms ‘vitamin D’ in conjunction with ‘kidney cancer’, ‘bladder cancer’, ‘prostate cancer’, and ‘testis cancer’. Autoalerts in Medline were also run and reference lists of original articles, review articles, and book chapters were searched for further eligible articles.

Results

In recent years, vitamin D has received vast attention due to suggestions that it may have a crucial role in the prevention and therapy of various cancers. Many epidemiologic studies have reported the impact of VD3 on preventing several cancers and other pathologies. Assuming that vitamin D status changes cancer risk, enough vitamin D supply would be an easy, economical, and safe cancer incidence and mortality reduction method. However, despite numerous researches, the role of vitamin D in cancer incidence and therapy remains unclear.

Conclusions

The impact of vitamin D is well described in breast, colon, and prostate cancer; yet, there is only little published about other malignancies.

The role of micronutrients in the risk of urinary tract cancer

Prostate, bladder and kidney cancers remain the most common urological malignancies worldwide, and the prevention and treatment of these diseases pose a challenge to clinicians. In recent decades, many studies have been conducted to assess the association between supplementation with selected vitamins and elements and urinary tract tumour initiation and development. Here, we review the relationship between vitamins A, B, D, and E, in addition to calcium, selenium, and zinc, and the risk of developing prostate, kidney and bladder cancer. A relatively consistent body of evidence suggests that large daily doses of calcium (> 2,000 mg/day) increase the risk of prostate cancer. Similarly, supplementation with 400 IU/day of vitamin E carries a significant risk of prostate cancer. However, there have been many conflicting results regarding the effect of these nutrients on kidney and bladder neoplasms. Moreover, the role of other compounds in urinary tract carcinogenesis needs further clarification.

Bladder Cancer is Associated with Low Plasma 25-hydroxyvitamin D Concentrations in Tunisian Population

Little evidence suggests an impact of vitamin D on bladder cancer risk in Caucasians. This study aimed to investigate association of plasma 25-hydroxyvitamin D (25-OHD) with urothelial bladder cancer (UBC) risk in Tunisians. A case-control study included 250 patients with UBC and 250 healthy controls. Plasma 25-OHD was assessed by a competitive chemiluminescence immunoassay. Vitamin D deficiency and insufficiency were defined as 25-OHD <30 nmol/L and 30 to 49.99 nmol/L, respectively. Logistic regression models adjusting for gender, age, smoking status, duration of smoking, occupational exposure, and season were applied. Vitamin D deficiency (50.4% vs. 34.8%; P < 0.001) and insufficiency (40.4% vs. 26.8%; P < 0.001) were more frequent in patients than controls. Multivariate analysis showed that UBC is associated with vitamin D deficiency [odd-ratio (95% confidence interval), 3.71 (1.76-7.80); P = 0.001] and vitamin D insufficiency [2.65 (1.40-5.01); P = 0.003]. Other predictors of UBC were female gender, tobacco use, smoking duration, and occupational exposure. Plasma 25-OHD concentrations are low in Tunisian patients with UBC. These findings support experimental and epidemiological evidence of protective role of vitamin D against UBC but could not ascertain causal relationship. Further prospective studies and clinical trials are warranted to check causality.

Steroid Hormone Receptor Signals as Prognosticators for Urothelial Tumor

There is a substantial amount of preclinical or clinical evidence suggesting that steroid hormone receptor-mediated signals play a critical role in urothelial tumorigenesis and tumor progression. These receptors include androgen receptor, estrogen receptors, glucocorticoid receptor, progesterone receptor, vitamin D receptor, retinoid receptors, peroxisome proliferator-activated receptors, and others including orphan receptors. In particular, studies using urothelial cancer tissue specimens have demonstrated that elevated or reduced expression of these receptors as well as alterations of their upstream or downstream pathways correlates with patient outcomes. This review summarizes and discusses available data suggesting that steroid hormone receptors and related signals serve as biomarkers for urothelial carcinoma and are able to predict tumor recurrence or progression.

Association of FokI polymorphism of vitamin D receptor with urothelial bladder cancer in Tunisians: role of tobacco smoking and plasma vitamin D concentration

The aim of the study was to test whether the VDR FokI polymorphism is associated with the risk of urothelial bladder cancer (UBC) in Tunisians. The study included 200 unrelated patients with UBC and 200 healthy controls. Genotyping of the VDR FokI polymorphism was determined by PCR-RFLP method. Plasma 25-hydroxyvitamin D concentrations were measured by immunoassay. Binary logistic regression model was applied to test how the association of VDR FokI polymorphism is independent of potential confounding factors. Genotype distribution (FF, 45 vs. 55 %; Ff, 52.1 vs. 47.9 %, and ff, 12 vs. 5.5 %, respectively) and allele frequencies (F, 66.5 vs. 74.8 % and f, 33.5 vs. 25.2 %, respectively) were significantly different between UBC patients and controls. The "ff" genotype [OR (95 % CI), 2.66 (1.24-5.73); p = 0.012] and "f" allele [1.49 (1.09-2.02); p = 0.010] were associated with increased risk of UBC. The association remained significant in multivariate analysis. Stratified analyses showed that VDR FokI polymorphism is only associated with UBC risk in ever-smokers, subjects exposed to chemical carcinogens and those with plasma 25-hydroxyvitamin D over 12 μg/L. The "f" allele of VDR FokI polymorphism is associated with a higher risk of UBC in Tunisians, especially in smokers as well as subjects with occupational exposition and subjects without vitamin D deficiency. These results should be replicated in other ethnic groups and the influence of other genetic factors and environments on this association should be investigated.

Association of vitamin C, vitamin D, vitamin E and risk of bladder cancer: a dose-response meta-analysis

A dose-response meta-analysis was conducted to assess the association of vitamin C, D, E with risk of bladder cancer. Pertinent studies were identified in PubMed and Embase. The random-effect model was used. The relative risk (95% confidence interval) of bladder cancer was 0.99 (0.95–1.03) for every 100 IU/day increment in vitamin D from diet plus supplement and 0.95 (0.90–1.00) for every 10 nmol/L increment in circulating vitamin D. The effect for every 10 mg/day increment was 0.96 (0.90–1.02) for vitamin E from diet plus supplement, 0.83 (0.72–0.95) from diet and 0.88 (0.67–1.15) from supplement, and the effect was 0.84 (0.76–0.94) for every 1 mg/dL increment in circulating α-Tocopherol and 1.22 (1.00–1.49) for every 0.1 mg/dL increment in circulating γ-Tocopherol. The observed association for vitamin D and vitamin E was significant among smokers but not among non-smokers. No significant association was found between vitamin C and risk of bladder cancer in the dose-response analysis. Based on the dose-response analysis, the risk of bladder cancer might be inversely associated with vitamin D and E (especially α-Tocopherol), but positively associated with γ-Tocopherol.

1 alpha, 25-dihydroxylvitamin D3 promotes Bacillus Calmette-Guérin immunotherapy of bladder cancer

Bacillus Calmette-Guérin (BCG), a vaccine against tuberculosis(TB), has been used and proven to be one of the most effective treatments for non-muscle invasive bladder cancer (BCa). However, the mechanisms of BCG action have not been completely understood, thereby limiting the improvement of BCG therapy. Vitamin D deficiency has been associated with a high risk of TB infection, and the beneficial effect of UV exposure in TB patients was proven to be mediated via activation of vitamin D signals of innate immune cells. Thus, vitamin D signals might be involved in mediating BCG immunotherapy. To test this hypothesis, we examined the impact of 1 alpha, 25-dihydroxyvitamin D3 (1,25-VD) on BCG-induced response in BCa cells and macrophage cells. Our data revealed that 1,25-VD promotes BCG-induced interleukin 8 (IL-8) secretion by BCa cells, consequently inducing the migration of macrophage, THP-1. This THP-1 cell migration promoted by 1,25-VD can be blocked by IL-8 neutralized antibody. Furthermore, 1,25-VD increased BCG-induced expression of macrophage markers in THP-1 cell, and enhanced the BCG-induced THP-1 cytotoxicity against low-grade BCa cells. Importantly, a pre-clinical trial using the N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced BCa mouse model revealed that intravesical co-treatment of 1,25-VD with BCG can prolong mice survival. These data demonstrate a novel mechanism by which 1,25-VD promotes BCG-mediated anti-BCa pathways and provides a platform for improving BCG efficacy with combination of 1,25-VD.

Effects of 1α,25-dihydroxyvitamin D3 , the natural vitamin D receptor ligand, on the pharmacokinetics of cefdinir and cefadroxil, organic anion transporter substrates, in rat

Evidence in the literature suggests that 1α,25-dihydroxyvitamin D3 [1,25(OH)2 D3 ], the vitamin D receptor ligand, down-regulated the expression of the rat renal organic anion (renal organic anion transporter, rOAT) and oligopeptide (rPEPT) transporters, but increased intestinal rPEPT1 expression. We investigated, in rats, the intravenous and oral pharmacokinetics of 2 mg/kg cefdinir and cefadroxil, two cephalosporins that are eliminated via renal OAT1/OAT3 and are substrates of PEPT1/PEPT2, with and without 1,25(OH)2 D3 treatment. The area under the plasma concentration-time curve (AUC) of cefdinir or cefadroxil after 1,25(OH)2 D3 treatment was increased significantly because of decreased clearance (CL). Both kidney uptake and cumulative urinary recovery were significantly decreased, whereas liver uptake and fecal recovery remained unchanged in 1,25(OH)2 D3 -treated rats. Similar changes in AUC and CL were observed for both drugs upon coadministration of probenecid, the OAT inhibitor. Oral availability of cefdinir and cefadroxil remained unchanged with 1,25(OH)2 D3 treatment, suggesting lack of a role for intestinal rPEPT1. Rather, reduction of rOAT1/rOAT3 mRNA expression in kidney with 1,25(OH)2 D3 -treatment was observed, confirmed by decreased function in MDCKII cells overexpressing human OAT1 and OAT3. These composite results suggest that 1,25(OH)2 D3 treatment reduces cefdinir and cefadroxil clearances by diminution of renal OAT1/OAT3 expression, implicating a role for 1,25(OH)2 D3 in eliciting transporter-based drug interactions.

Low plasma 25-hydroxyvitamin D and risk of tobacco-related cancer

BACKGROUND

Tobacco smoke chemicals may influence vitamin D metabolism and function, and conversely vitamin D may modify the carcinogenicity of tobacco smoke chemicals. We tested the hypothesis that lower plasma 25-hydroxyvitamin D [25(OH)D] is associated with a higher risk of tobacco-related cancer in the general population.

METHODS

A prospective population-based cohort of 9791 individuals from the Copenhagen City Heart Study who were free of cancer at baseline was followed from 1981-1983 until December 2008 with 100% complete follow-up.

RESULTS

During up to 28 years of follow-up, 1081 participants developed a tobacco-related cancer and 1506 developed other cancers. Decreasing 25(OH)D concentrations, subdivided by clinical categories or by seasonally adjusted percentile categories, were associated with increasing cumulative incidence of tobacco-related cancer (log-rank trend P = 2 × 10(-6) and P = 5 × 10(-9)). Multivariable adjusted hazard ratios of tobacco-related cancer were 1.75 (95% CI, 1.33-2.30) for 25(OH)D <5 vs ≥20 ng/mL, and 2.07 (1.63-2.62) for ≤5th vs >66th percentile. Also, multivariable adjusted hazard ratios for a 50% reduction in 25(OH)D were 1.20 (1.13-1.28) for any tobacco-related cancer, 1.19 (95% CI, 1.09-1.31) for lung cancer, 1.44 (1.19-1.73) for head and neck cancer, 1.28 (1.06-1.54) for bladder cancer, 1.34 (1.04-1.73) for kidney cancer, and 0.95 (0.89-1.01) for other cancers.

CONCLUSIONS

Lower plasma 25(OH)D was associated with higher risk of tobacco-related cancers, but not with risk of other cancers.

Plasma 25-hydroxyvitamin D(3) and bladder cancer risk according to tumor stage and FGFR3 status: a mechanism-based epidemiological study

BACKGROUND

Previous evidence suggests that 25-hydroxyvitamin D(3) [25(OH)D(3)] protects against several cancers. However, little is known regarding urothelial bladder cancer (UBC). We analyzed the association between plasma 25(OH)D(3) and overall risk of UBC, as well as according to stage and FGFR3 molecular subphenotypes.

METHODS

Plasma concentrations of 25(OH)D(3) in 1125 cases with UBC and 1028 control subjects were determined by a chemiluminescence immunoassay. FGFR3 mutational status and expression in tumor tissue were assessed. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression adjusting for potential confounders. Analyses were further stratified by tumor invasiveness and grade, FGFR3 expression, and smoking status. Cell proliferation was measured in human UBC cell lines cultured with 1α,25-dihydroxyvitamin D(3).

RESULTS

A statistically significantly increased risk of UBC was observed among subjects presenting the lowest concentrations of 25(OH)D(3) (OR(adj) = 1.83; 95% CI = 1.19 to 2.82; P = .006), showing a dose-response effect (P (trend) = .004). The association was stronger for patients with muscle-invasive tumors, especially among low-FGFR3 expressers (OR(adj) = 5.94; 95% CI = 1.72 to 20.45; P = .005). The biological plausibility of these associations is supported by the fact that, in vitro, 1α,25-dihydroxyvitamin D(3) upregulates FGFR3 expression in UBC cell lines with low levels of wild-type FGFR3.

CONCLUSION

These findings support a role of vitamin D in the pathogenesis of UBC and show that 25(OH)D(3) levels are associated with FGFR3 expression in the tumor. Because FGFR3 mutation and overexpression are markers of better outcome, our findings suggest that individuals with low levels of plasma 25(OH)D(3) may be at high risk of more aggressive forms of UBC.

Influence of vitamin D binding protein on the association between circulating vitamin D and risk of bladder cancer

BACKGROUND

There is little research investigating the role of vitamin D binding protein (DBP) in the association between 25-hydroxyvitamin D (25(OH)D) and disease risk.

METHODS

Within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, 250 bladder cancer cases were randomly sampled and matched 1:1 to controls on age and date of blood collection. Odds ratios (OR) and 95% confidence intervals (CI) of bladder cancer were estimated by quartiles of DBP (measured by ELISA), 25(OH)D and the molar ratio of 25(OH)D:DBP, a proxy for free circulating 25(OH)D. Analyses were also conducted stratifying 25(OH)D by DBP (median split) and vice versa.

RESULTS

We found no direct association between circulating DBP levels and bladder cancer risk (P-trend=0.83). The inverse association between 25(OH)D and bladder cancer risk was unchanged after adjustment for DBP (Q4 vs Q1 OR=0.61, 95% CI=0.36-1.05; P-trend=0.04), and was stronger among men with lower DBP (low DBP: 25(OH)D Q4 vs Q1 OR=0.47, 95% CI=0.23-1.00; high DBP: 25(OH)D Q4 vs Q1 OR=0.83, 95% CI=0.40-1.75; P for interaction=0.11).

CONCLUSION

Our findings provide additional support for an aetiologic role for vitamin D in bladder cancer and suggest that free, rather than total, circulating vitamin D may be a more relevant exposure when examining bladder and, perhaps, other cancers.

Downregulation of Ral GTPase-activating protein promotes tumor invasion and metastasis of bladder cancer

The small GTPase Ral is known to be highly activated in several human cancers, such as bladder, colon and pancreas cancers. It is reported that activated Ral is involved in cell proliferation, migration and metastasis of bladder cancer. This protein is activated by Ral guanine nucleotide exchange factors (RalGEFs) and inactivated by Ral GTPase-activating proteins (RalGAPs), the latter of which consist of heterodimers containing a catalytic α1 or α2 subunit and a common β subunit. In Ras-driven cancers, such as pancreas and colon cancers, constitutively active Ras mutant activates Ral through interaction with RalGEFs, which contain the Ras association domain. However, little is known with regard to the mechanism that governs aberrant activation of Ral in bladder cancer, in which Ras mutations are relatively infrequent. Here, we show that Ral was highly activated in invasive bladder cancer cells due to reduced expression of RalGAPα2, the dominant catalytic subunit in bladder, rather than increased expression of RalGEFs. Exogenous expression of wild-type RalGAPα2 in KU7 bladder cancer cells with invasive phenotype, but not mutant RalGAPα2-N1742K lacking RalGAP activity, resulted in attenuated cell migration in vitro and lung metastasis in vivo. Furthermore, genetic ablation of Ralgapa2 promoted tumor invasion in a chemically-induced murine bladder cancer model. Importantly, immunohistochemical analysis of human bladder cancer specimens revealed that lower expression of RalGAPα2 was associated with advanced clinical stage and poor survival of patients. Collectively, these results are highly indicative that attenuated expression of RalGAPα2 leads to disease progression of bladder cancer through enhancement of Ral activity.

Vitamin D and cancer: clinical aspects

There are substantial preclinical and epidemiologic data that suggest that vitamin D plays a role in the prevention and treatment of cancer. Numerous observational studies have shown that low blood levels of 25(OH) vitamin D (cholecalciferol), estimated by geographical location, diet and activity assessment or measured serum levels are associated with a higher risk of cancer and worse cancer-specific survival as well as numerous morbidities to e.g. cardiovascular disease, stroke, infection, autoimmune disease, and neuromuscular dysfunction among large populations. A considerable number of in vitro and in vivo studies indicate that the most active metabolite of vitamin D--1,25-dihydroxycholecalciferol or calcitriol--has anti-proliferative, pro-apoptotic, pro-differentiating, and anti-angiogenic properties. Combined treatment of calcitriol and many types of cytotoxic agents has synergistic or at least additive effects. However, clinical trials testing these hypotheses have been less encouraging, though a number of methodological, pharmacological, and pharmaceutical issues confound all trials ever conducted. In order to properly assess the clinical value of vitamin D, its metabolites and analogs in cancer prevention and treatment, more studies are needed.

Serum vitamin D and risk of bladder cancer

Vitamin D may protect against several cancers, but data about the association between circulating vitamin D and bladder cancer are limited. Within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a randomized controlled trial conducted to determine the effects of α-tocopherol and β-carotene supplements on cancer incidence in male smokers, 250 bladder cancer cases were randomly sampled by month of blood collection. Controls were matched 1:1 to cases on age at randomization and date of blood collection. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) of bladder cancer by a priori categories of baseline serum 25-hydroxyvitamin D [25(OH)D; i.e., <25, 25 to <37.5, 37.5 to <50, ≥50 nmol/L] and by season-specific quartiles. After multivariable adjustment, we found that lower 25(OH)D was associated with a statistically significantly increased risk of bladder cancer (versus ≥50 nmol/L; <25 nmol/L: OR, 1.73; 95% CI, 1.03-2.91; 25 to <37.5 nmol/L: OR, 1.81; 95% CI, 1.05-3.14; 37.5 to <50 nmol/L: OR, 1.76; 95% CI, 1.02-3.02; P trend=0.04). Similarly, increased risks for the lowest vitamin D category were observed when season-specific quartiles were used (Q1 versus Q4: OR, 1.63; 95% CI, 0.96-2.75; P trend=0.03). In this prospective study of male smokers, lower serum 25(OH)D was associated with an increased risk of bladder cancer. Future studies should examine the association in other populations, especially nonsmokers and women.

1,25D3 enhances antitumor activity of gemcitabine and cisplatin in human bladder cancer models

BACKGROUND

1,25 dihydroxyvitamin D3 (1,25D3) potentiates the cytotoxic effects of several common chemotherapeutic agents. The combination of gemcitabine and cisplatin is a current standard chemotherapy regimen for bladder cancer. The authors investigated whether 1,25D3 could enhance the antitumor activity of gemcitabine and cisplatin in bladder cancer model systems.

METHODS

Human bladder cancer T24 and UMUC3 cells were pretreated with 1,25D3 followed by gemcitabine and cisplatin. Apoptosis was assessed by annexin V staining. Caspase activation was examined by immunoblot analysis and substrate-based caspase activity assay. The cytotoxic effects were examined by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and in vitro clonogenic assay. p73 protein levels were assessed by immunoblot analysis. Knockdown of p73 was achieved by siRNA. The in vivo antitumor activity was assessed by in vivo excision clonogenic assay and tumor regrowth delay in the T24 xenograft model.

RESULTS

1,25D3 pretreatment enhanced gemcitabine and cisplatin-induced apoptosis and the activities of caspases 8, 9, and 3 in T24 and UMUC3 cells. 1,25D3 synergistically reduced gemcitabine and cisplatin-suppressed surviving fraction in T24 cells. 1,25D3, gemcitabine, or cisplatin induced p73 accumulation, which was enhanced by gemcitabine and cisplatin or 1,25D3 and gemcitabine and cisplatin. p73 expression was lower in human primary bladder tumor tissue compared with adjacent normal tissue. Knockdown of p73 increased clonogenic capacity of T24 cells treated with 1,25D3, gemcitabine and cisplatin, or 1,25D3 and gemcitabine and cisplatin. 1,25D3 and gemcitabine and cisplatin combination enhanced tumor regression compared with 1,25D3 or gemcitabine and cisplatin alone.

CONCLUSIONS

1,25D3 potentiates gemcitabine and cisplatin-mediated growth inhibition in human bladder cancer models in vitro and in vivo, which involves p73 induction and apoptosis.

Vitamin D receptor agonists target static, dynamic, and inflammatory components of benign prostatic hyperplasia

The bioactive form of vitamin D, 1,25-dihydroxyvitamin D(3), is a secosteroid hormone that binds to the vitamin D receptor (VDR), a member of the nuclear receptor superfamily, and modulates a variety of biological functions. The VDR is expressed by most cell types, including cells of the urogenital system, such as prostate and bladder cells. In particular, the prostate is a target organ of VDR agonists and represents an extrarenal synthesis site of 1,25-dihydroxyvitamin D(3). We have analyzed the capacity of VDR agonists to treat benign prostatic hyperplasia (BPH), a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic component responsible for urinary irritative symptoms, and an inflammatory component. Data reviewed here demonstrate that VDR agonists, and notably elocalcitol, reduce the static component of BPH by inhibiting the activity of intraprostatic growth factors downstream of the androgen receptor, the dynamic component by targeting the RhoA/ROCK pathway in prostate and bladder cells, and the inflammatory component by targeting the NF-kappaB pathway.

Minerals and vitamins and the risk of bladder cancer: results from the New Hampshire Study

Objective

Although the effect of fruit and vegetables on the risk of bladder cancer has been widely studied, little is known about their micronutrient components. Our aim was to investigate associations between minerals and vitamins and bladder cancer.

Methods

A case–control study was conducted in New Hampshire, USA. Dietary data were collected from 322 cases and 239 controls using a 121-item food frequency questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression adjusting for sex, age, smoking characteristics, and energy intake.

Results

The ORs (95% CI) for highest quartile versus lowest quartile for total intake of vitamin E was 0.66 (0.36–1.20; p trend = 0.09) and 0.49 (0.21–1.17; p trend = 0.13) for dietary phosphorus. The odds of bladder cancer for heavy smokers with the highest total intake of vitamin E, carotenoids, and niacin were 0.58 (0.34–0.99), 0.62 (0.36–1.09), and 0.66 (0.39–1.14), respectively. Higher total intakes of carotenoids, vitamin D, thiamin, niacin, and vitamin E were inversely related to bladder cancer risk among older individuals.

Conclusion

Our findings suggest further investigation of the effect of vitamin E, carotenoids, vitamin D, thiamin, and niacin on bladder cancer risk may be warranted. Future studies should focus on high risk groups such as heavy smokers and older individuals.

Nitric oxide as a target of complementary and alternative medicines to prevent and treat inflammation and cancer

Nitric oxide (NO) and associated reactive nitrogen species (RNS) are involved in many physiological functions. There has been an ongoing debate to whether RNS can inhibit or perpetuate chronic inflammation and associated carcinogenesis. Although the final outcome depends on the genetic make-up of its target, the surrounding microenvironment, the activity and localization of nitric oxide synthase (NOS) isoforms, and overall levels of NO/RNS, evidence is accumulating that in general, RNS drive inflammation and cancers associated with inflammation. To this end, many complementary and alternative medicines (CAMs) that work in chemoprevention associated with chronic inflammation, are inhibitors of excessive NO observed in inflammatory conditions. Here, we review recent literature outlining a role of NO/RNS in chronic inflammation and cancer, and point toward NO as one of several targets for the success of CAMs in treating chronic inflammation and cancer associated with this inflammation.

Shared occupational risks for transitional cell cancer of the bladder and renal pelvis among men and women in Sweden

BACKGROUND

Unlike cancer of the bladder, cancer of the renal pelvis is not considered an occupational cancer and little is known about risks among women.

METHODS

Using the Swedish national census and cancer registry-linked data (1971-1989), we identified transitional cell cancers of the renal pelvis (N = 1,374) and bladder (N = 21,591). Correlation between cancer sites for the standardized incidence ratios (SIR) were determined using Pearson's coefficient of the log SIR. Relative risks of job exposure matrix variables were calculated using Poisson regression.

RESULTS

Both cancer sites were significantly elevated among women and men employed in the machine/electronics industry, sedentary work, and indoor work, and men in the metal industry. The highest proportion of the bladder (12%) and renal pelvis (14%) cancers occurred among men employed in shop and construction metal work. Risks by industry were more correlated among women (r = 0.49, P = 0.002) than men (r = 0.24, P = 0.04). Cancers of the renal pelvis were elevated in several occupational and industry groups for which there was no elevated bladder cancer risk.

CONCLUSION

Cancers of the renal pelvis and bladder share common occupational risk factors that may be more frequent among women. In addition, there may be some jobs that pose an increased risk specifically for cancer of the renal pelvis but not bladder.

Anti-proliferative effects of calcitriol on endothelial cells derived from two different microenvironments

Calcitriol (1,25-dihydroxycholecalciferol), the active form of Vitamin D, is anti-proliferative in tumor cells and tumor-derived endothelial cells (TDEC). However, endothelial cells isolated from normal tissues as cell lines or freshly isolated cells or from implanted Matrigel plugs (MDEC) are relatively resistant. Both TDEC and MDEC express similar amounts of Vitamin D receptor (VDR) protein. Although the VDR from TDEC has higher binding affinity for calcitriol than those from MDEC, VDR in both cell types translocates to the nucleus and transactivates the 24-hydroxylase promoter-luciferase construct. Calcitriol selectively inhibits the growth of TDEC but not MDEC by inducing G(0)/G(1) cell cycle arrest and by promoting apoptosis. This selectivity appears to be related to 24-hydroxylase (CYP24) expression. Calcitriol significantly induced CYP24 expression in MDEC but not in TDEC and inhibition of CYP24 activity in MDEC restores their sensitivity to calcitriol. These findings indicate that the induction of CYP24 expression differs in endothelial cells isolated from different microenvironments (TDEC versus MDEC) and that this distinction contributes to selective calcitriol-mediated growth inhibition in these cell types.

Pre-clinical evidence and clinical translation of benign prostatic hyperplasia treatment by the vitamin D receptor agonist BXL-628 (Elocalcitol)

The active form of vitamin D, 1,25-dihydroxyvitamin D3, is a secosteroid hormone that binds to the vitamin D receptor (VDR), a member of the superfamily of nuclear receptors, and exerts a number of diverse biological functions. The natural hormone and synthetic VDR agonists are well known for their capacity to control calcium and bone metabolism, but they also regulate proliferation and differentiation of many cell types, and possess exquisite immunoregulatory properties, mostly by targeting dendritic cells (DC) and T cells. These properties have been clinically exploited in the treatment of different diseases, from secondary hyperparathyroidism to osteoporosis to psoriasis. The VDR is expressed by most cell types, including cells of the urogenital system such as prostate and bladder cells. In particular, the prostate has been recognized as a target organ of VDR agonists and represents an extra-renal synthesis site of 1,25-dihydroxyvitamin D3, but its capacity to respond to VDR agonists has, so far, been probed only for the treatment of prostate cancer. We have taken a different approach, and have analysed the capacity of VDR agonists to treat benign prostatic hyperplasia (BPH), a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic component responsible for urinary irritative symptoms, and a possible inflammatory component. Pre-clinical data reviewed here demonstrate that VDR agonists, and notably BXL-628 (Elocalcitol), reduce the static component of BPH by inhibiting the activity of intra-prostatic growth factors downstream of the androgen receptor, and the dynamic component by targeting bladder cells. These data have led to a proof-of-concept clinical study that has successfully shown arrest of prostate growth in BPH patients treated with BXL-628. Ongoing clinical studies will assess the capacity of this VDR agonist to reduce symptoms and ameliorate flow parameters in BPH-affected individuals. The pronounced effects of BXL-628 on bladder smooth muscle cells and its anti-inflammatory properties indeed anticipate beneficial effects also on BPH-related lower urinary tract symptoms.

1alpha,25-dihydroxyvitamin D3 inhibits prostate cancer cell invasion via modulation of selective proteases

Inhibition of invasion and metastasis has become a new approach for treatment of advanced prostate cancer in which secondary hormone therapy has failed. Accumulating evidence indicates that 1alpha,25-dihydroxyvitamin D3 (1,25-VD) suppresses prostate cancer progression by inhibition of tumor growth and metastasis. However, the detailed mechanisms underlying these effects remain to be determined. Here, we used the in vitro cell invasion assay to demonstrate that 1,25-VD inhibits the invasive ability of human prostate cancer cell lines, LNCaP, PC-3 and DU 145. Three major groups of proteases, the matrix metalloproteinases (MMPs), the plasminogen activators (PAs) and the cathepsins (CPs), that are involved in tumor invasion were then examined for changes in activity and expression after 1,25-VD treatment. We found that 1,25-VD decreased MMP-9 and CPs, but not PAs activities, while it increased the activity of their counterparts, tissue inhibitors of metalloproteinase-1 (TIMP-1) and cathepsin inhibitors. Mechanistic studies showed that 1,25-VD did not suppress MMP-9 expression at the transcriptional level, but reduced its mRNA stability. In addition, 1,25-VD increased AP-1 complexes binding to TIMP-1 promoter, which contributed to the enhancement of TIMP-1 activity, and thus resulted in inhibition of MMP activity and tumor invasion. These findings support the idea that vitamin D-based therapies might be beneficial in the management of advanced prostate cancer, especially among patients who have higher MMP-9 and CPs activities.

Tolterodine for the treatment of overactive bladder: a review

Overactive bladder (OAB) is a prevalent condition. Numerous clinical trials have demonstrated the efficacy and safety of immediate release tolterodine in the treatment of OAB in different patient populations. This review details the characteristics, clinical efficacy and safety of extended release (ER) tolterodine. This formulation yields a flatter serum concentration profile and provides clinically meaningful symptom improvement as early as week 1 of treatment. Tolterodine ER is effective in diverse patient populations with varying levels of symptom severity, and efficacy is maintained with long-term treatment. Tolterodine is an effective, safe, and convenient treatment option for long-term relief of OAB symptoms.

1,25-Dihydroxy vitamin D3: can it be an effective therapeutic option for aggressive fibromatosis

Aggressive fibromatosis (AF), also known as desmoid tumor is a monoclonal fibroblastic proliferation in a collagen matrix that arises in musculoaponeurotic structures. Though considered as benign, they are locally invasive and their propensity for recurrence after conservative surgery is well documented. Addition of postoperative adjuvant radiotherapy produces higher local control rates, although recurrence rates are still high in patients with positive margins. The antineoplastic activity of vitamin D has been demonstrated both in vitro and in vivo models of several cancers. The proposed mechanisms for antineoplastic activity include inhibition of proliferation associated with cell cycle arrest, induction of apoptosis and reduction in invasiveness and angiogenesis. It has also been shown that vitamin D has a negative impact on collagen homeostasis by inhibiting the formation and increasing its degradation. Since vitamin D has an antineoplastic activity and negative effect on collagen synthesis and deposition, it is proposed that 1,25-dihydroxy vitamin D3 can be a right therapeutic option for the management of desmoid tumors.

Calcitriol in cancer treatment: From the lab to the clinic

1,25-Dihydroxyvitamin D (calcitriol), the most active metabolite of vitamin D, has significant antineoplastic activity in preclinical models. Several mechanisms of activity have been proposed. These include inhibition of proliferation associated with cell cycle arrest and, in some models, differentiation, reduction in invasiveness and angiogenesis, and induction of apoptosis. Proposed mechanisms differ between tumor models and experimental conditions, and no unifying hypothesis about the mechanism of antineoplastic activity has emerged. Synergistic and/or additive effects with cytotoxic chemotherapy, radiation, and other cancer drugs have been reported. Significantly supraphysiological concentrations of calcitriol are required for antineoplastic effects. Such concentrations are not achievable in patients when calcitriol is dosed daily due to predictable hypercalcemia and hypercalcuria; however, phase I trials have demonstrated that intermittent dosing allows substantial dose escalation and has produced potentially therapeutic peak calcitriol concentrations. Recently, a phase II study reported encouraging levels of activity for the combination of high-dose calcitriol and docetaxel administered on a weekly schedule in patients with androgen-independent prostate cancer. This regimen is now under study in a placebo-controlled randomized trial in androgen-independent prostate cancer and in phase II studies in several other tumor types. Further work is needed to elucidate the molecular mechanisms of antineoplastic activity and optimal clinical applications of calcitriol in cancer.

Efficacy of Paclitaxel Released From Bio-Adhesive Polymer Microspheres on Model Superficial Bladder Cancer

PURPOSE

We aimed to promote the efficacy of paclitaxel in intracavitary treatment of superficial transitional cell carcinoma of the bladder by designing bio-adhesive microspheres capable of achieving controlled release of the drug at the urothelium/urine interface.

MATERIALS AND METHODS

Poly(methylidene malonate 2.1.2) microspheres encapsulating paclitaxel were prepared by a single emulsion method. Bioactivity of the released paclitaxel was confirmed by assessing cytotoxicity on MBT-2, a bladder cancer cell line. Biodistribution of particles after bladder instillation was assessed by confocal microscopy and scanning electron microscopy. In vivo studies were performed in Balb/c mice after bladder cancer was induced by BBN (N-n-Butyl-N-butan-4-ol-nitrosamine) in drinking water. The efficacy of intravesical injections of conventional and microsphere paclitaxel was assessed by histology and survival rates.

RESULTS

Spherical 5 microm microspheres with 5% weight per weight paclitaxel loading ensured sustained release of bioactive paclitaxel. After bladder instillation the microspheres adhered to the mucosa and remained in the bladder lumen for at least 48 hours. In the BBN induced bladder cancer model compared with controls the 9-week survival rate was significantly improved by 2 injections of paclitaxel bio-adhesive microparticles. Microscopic evaluation confirmed the lower incidence of carcinoma in situ and high grade transitional cell carcinoma after injections of paclitaxel bio-adhesive microparticles compared with controls and with injections of similar doses of the conventional paclitaxel formulation.

CONCLUSIONS

Intravesical administration of poly(methylidene malonate 2.1.2) paclitaxel microspheres is a promising approach for intracavitary chemotherapy of superficial bladder cancer.

Bladder cancer prevention. Part I: what do I tell my patients about lifestyle changes and dietary supplements?

PURPOSE OF REVIEW

Comprehensive reviews of lifestyle changes and dietary supplements that may prevent bladder cancer are needed in order to facilitate discussions between clinicians and patients.

RECENT FINDINGS

Novel data exist that numerous lifestyle/diet and dietary supplements may lower the risk of this disease. For example, reducing arsenic exposure, incorporating dietary changes, and vitamin E supplements continue to accumulate research that supports their use with some patients at a higher risk for this disease. Regardless, smoking cessation seems to have the largest impact on reducing risk and incorporating these other changes after smoking cessation may reduce an individual's risk to an even greater extent.

SUMMARY

However, a large percentage of cases of individuals diagnosed with this cancer apparently have no known etiology. Diets lower in calories or possibly specific sub-types of fat, and higher in fruits and especially vegetables, seem to provide some protection. Other dietary/supplement options may affect risk, but these benefits could be seriously attenuated by smoking. Dietary selenium, but currently not selenium supplements, may also affect risk, especially in non-smokers. Dietary vitamin E, and vitamin E supplements, may provide some protection. Non-selective (e.g. non-steroidal anti-inflammatory drugs) and selective cyclooxygenase-2 inhibitors are generating interest because bladder tumors seem to contain higher concentrations of this enzyme. Drinking-water quality, especially arsenic concentrations, may seriously affect risk. Providing recommendations for patients with regard to some of these lifestyle modifications is currently recommended because the majority of these alterations are also recommended currently for cardiovascular or general oncology disease reduction.

Development of weekly high-dose calcitriol based therapy for prostate cancer

Calcitriol, the principal biologically active ligand of the Vitamin D receptor (VDR), has been shown to inhibit cancer cell proliferation in in vitro and in vivo models of prostate cancer and a wide range of other neoplasms. In addition, calcitriol's activity appears to be additive, and in some experimental systems, synergistic with dexamethasone and several cytotoxic chemotherapy agents. While effects on progression through the cell cycle, induction of apoptosis, inhibition of angiogenesis, and reduction in tumor invasiveness have been demonstrated, the exact mechanisms of VDR-mediated antineoplastic activity remain incompletely understood. Antineoplastic activity of calcitriol requires substantially supraphysiologic concentrations of this compound. Dose escalation of calcitriol administered daily was severely limited by predictable hypercalcemia and/or hypercalcuria. This limitation has been overcome with intermittent dosing of calcitriol. At Oregon Health & Science University, weekly oral administration of calcitriol allowed the attainment of peak serum calcitriol concentrations well above 1 nM, a concentration that inhibits prostate cancer proliferation by more than 50% in vitro. Weekly high-dose calcitriol was then combined with weekly docetaxel in a Phase II clinical trial carried out in men with metastatic androgen-independent prostate cancer. Treatment resulted in PSA response (defined as a confirmed 50% reduction) in 81% of patients. This level of activity, as well as the median time to progression of 11.4 months and median survival of 19.5 months, compared favorably to results with docetaxel alone and led to the development of a recently initiated randomized trial of docetaxel with calcitriol or placebo in the same patient population.

Weekly high-dose calcitriol and docetaxel in metastatic androgen-independent prostate cancer

PURPOSE

To determine the safety and efficacy of weekly high-dose oral calcitriol (Rocaltrol, Roche Pharmaceuticals, Basel, Switzerland) and docetaxel (Taxotere, Aventis Pharmaceuticals, Bridgewater, NJ) in patients with metastatic androgen-independent prostate cancer (AIPC).

PATIENTS AND METHODS

Thirty-seven patients were treated with oral calcitriol (0.5 micro g/kg) on day 1 followed by docetaxel (36 mg/m(2)) on day 2, repeated weekly for 6 weeks of an 8-week cycle. Patients maintained a reduced calcium diet and increased oral hydration. Prostate-specific antigen (PSA) response was the primary end point, which was defined as a 50% reduction in PSA level confirmed 4 weeks later.

RESULTS

Thirty of 37 patients (81%; 95% confidence interval [CI], 68% to 94%) achieved a PSA response. Twenty-two patients (59%; 95% CI, 43% to 75%) had a confirmed > 75% reduction in PSA. Eight of the 15 patients with measurable disease (53%; 95% CI, 27% to 79%) had a confirmed partial response. Median time to progression was 11.4 months (95% CI, 8.7 to 14 months), and median survival was 19.5 months (95% CI, 15.3 months to incalculable). Overall survival at 1 year was 89% (95% CI, 74% to 95%). Treatment-related toxicity was generally similar to that expected with single-agent docetaxel. Pharmacokinetics of either calcitriol or docetaxel were not affected by the presence of its companion drug in an exploratory substudy.

CONCLUSION

The combination of weekly oral high-dose calcitriol and weekly docetaxel is a well-tolerated regimen for AIPC. PSA and measurable disease response rates as well as time to progression and survival are promising when compared with contemporary phase II studies of single-agent docetaxel in AIPC. Further study of this regimen is warranted.

Influence of vitamin D3 metabolites on cell proliferation and cytotoxicity of adriamycin in human normal and neoplastic cells

The common features of biological activity displayed by vitamin D family members and adriamycin suggest the possibility of synergistic effects of the combination of these compounds. Until now, the mechanisms responsible mainly for adriamycin cytotoxic action have not been indicated. Therefore, observation of the possible common cell targets for adriamycin and vitamin D metabolites could shed more light on the mechanisms of cytotoxic activity of adriamycin. In the present study, the influence of calcidiol (25-hydroxyvitamin D(3)) and calcitriol (1alpha,25-dihydroxyvitamin D(3)) on the proliferation and cytotoxicity of adriamycin was studied. The following cell lines were tested: normal human fibroblasts-CRL 1502, human melanoma cells-ME18 and its subline-ME18/R, resistant to adriamycin. As was shown, 72 h of incubation with calcidiol or calcitriol, both at 10 microM, inhibited growth (to approx. 60%) only of the ME18 cells. Dose and time dependence of this effect has been confirmed. Antiproliferative events did not correlate with an increase of adriamycin cytotoxicity. It was noted that calcidiol and calcitriol had no significant influence on the adriamycin IC(50) values in any cell lines tested. These results point to the divergent mechanisms of action of adriamycin and vitamin D(3) metabolites.

Vitamin D and systemic cancer: is this relevant to malignant melanoma?

1,25-dihydroxyvitamin D3[1,25(OH)2D3] is a well-known potent regulator of cell growth and differentiation and there is recent evidence of an effect on cell death, tumour invasion and angiogenesis, which makes it a candidate agent for cancer regulation. The classical synthetic pathway of 1,25(OH)2D3 involves 25- and 1 alpha-hydroxylation of vitamin D3, in the liver and kidney, respectively, of absorbed or skin-synthesized vitamin D3. There is recent focus on the importance in growth control of local metabolism of 1,25(OH)2D3, which is a function of local tissue synthetic hydroxylases and particularly the principal catabolizing enzyme, 24-hydroxylase. The classical signalling pathway of 1,25(OH)2D3 employs the vitamin D nuclear receptor (VDR), which is a transcription factor for 1,25(OH)2D3 target genes. Effects of this pathway include inhibition of cellular growth and invasion. Cytoplasmic signalling pathways are increasingly being recognized, which similarly may regulate growth and differentiation but also apoptosis. 1,25(OH)2D3 has a major inhibitory effect on the G1/S checkpoint of the cell cycle by upregulating the cyclin dependent kinase inhibitors p27 and p21, and by inhibiting cyclin D1. Indirect mechanisms include upregulation of transforming growth factor-beta and downregulation of the epidermal growth factor receptor. 1,25(OH)2D3 may induce apoptosis either indirectly through effects on the insulin-like growth receptor and tumour necrosis factor-alpha or more directly via the Bcl-2 family system, the ceramide pathway, the death receptors (e.g. Fas) and the stress-activated protein kinase pathways (Jun N terminal kinase and p38). Inhibition of tumour invasion and metastasis potential has been demonstrated and mechanisms include inhibition of serine proteinases, metalloproteinases and angiogenesis. The lines of evidence for an effect of vitamin D3 in systemic cancer are the laboratory demonstration of relevant effects on cellular growth, differentiation, apoptosis, malignant cell invasion and metastasis; epidemiological findings of an association of the occurrence and outcome of cancers with derangements of vitamin D3/1,25(OH)2D3 and the association of functional polymorphisms of the VDR with the occurrence of certain cancers. In addition, vitamin D3 analogues are being developed as cancer chemotherapy agents. There is accumulating evidence that the vitamin D3/1,25(OH)2D3/VDR axis is similarly important in malignant melanoma (MM). MM cells express the VDR, and the antiproliferative and prodifferentiation effects of 1,25(OH)2D3 have been shown in cultured melanocytes, MM cells and MM xenografts. Recently, an inhibitory effect on the spread of MM cells has been demonstrated, low serum levels of 1,25(OH)2D3 have been reported in MM patients and the VDR polymorphisms have been shown to be associated with both the occurrence and outcome of MM. The relationship between solar irradiation and MM is more complex than for the systemic cancers. As in other cancers, there is evidence of a protective effect of vitamin D3 in MM, but ultraviolet radiation, which is a principal source of vitamin D3, is mutagenic. Further work is necessary on the influence of serum vitamin D3 levels on the occurrence and prognosis of MM, the effects of sun protection measures on serum vitamin D3 levels in temperate climates and epidemiological studies on geographical factors and skin type on the prognosis of MM. Meanwhile, it would seem mandatory to ensure an adequate vitamin D3 status if sun exposure were seriously curtailed, certainly in relation to carcinoma of breast, prostate and colon and probably also MM.

Bladder cancer

Bladder cancer is a common and chemotherapy-responsive tumor, related to tobacco smoking, environmental arsenic exposure, industrial dye exposure, and parasitic schistosomiasis exposure. Both reduction of carcinogen exposure and chemoprevention, possibly with cyclooxygenase 2 inhibitors, should reduce the incidence. The search for the ideal screening and monitoring test continues with some promising new candidates, including survivin. Although 10-year survival can be achieved in 87% of early-stage patients with muscle-invasive disease rendered T(0) and 57% of those rendered T(1) at second look after transurethral resection bladder tumor, most still require radical cystectomy. Continued improvements in surgical techniques permit gains in quality of life after the procedure. Ten-year survival can still be achieved with cystectomy in the face of grossly positive lymph nodes in 32% of T(2) and 10% of T(3) patients. A recent meta-analysis indicates that preoperative irradiation is unlikely to be beneficial, but definitive chemoradiation can produce significant 5-year survival rates in nonoperative candidates and those desiring bladder preservation. The Intergroup now has preliminary data from a Southwest Oncology Group-based trial showing a significant benefit for neoadjuvant methotrexate, vinblastine, doxorubicin, and cisplatin. The regimen of gemcitabine and cisplatin is equally efficacious with less toxicity than methotrexate, vinblastine, doxorubicin, and cisplatin. It has been adopted as the standard arm in a phase III trial for advanced bladder cancer, comparing it with the triplet of gemcitabine, paclitaxel, and cisplatin. Other active agents in bladder cancer include ifosfamide, carboplatin, docetaxel, and vinorelbine, and various doublets of these agents are being tested in phase II trials, with promising results.

Potential lifestyle and dietary supplement options for the prevention and postdiagnosis of bladder cancer

Apart from smoking, certain occupational exposures, and schistosomiasis, little is known about other potential lifestyle risk factors for bladder cancer. Other investigations thus far have also been important because of the large number of individuals who are diagnosed with this cancer that apparently have no known risk factors. Preventing the recurrence of bladder cancer has generated some interest because several preliminary trials have found that a combination dietary supplement of vitamins and minerals or a probiotic agent (Lactobacillus casei) may impact this outcome favorably. Advising patients on some of these lifestyle modifications is currently recommended because the majority of them are also currently recommended for cardiovascular disease reduction.

Vitamin D and prostate cancer

The original hypothesis of Schwartz and Hulka (1990) proposing that vitamin D deficiency may be a risk factor for prostate cancer has triggered many studies. Epidemiological studies have supported this hypothesis with findings that sunlight exposure is inversely proportional to prostate cancer mortality and that prostate cancer risk is greater in men with lower levels of vitamin D (Hanchette and Schwartz, 1992; Corder et al, 1993; Ahonen et al, 2000). Prostate cancer cells express receptors for 1,25(OH)2D3 and some cell lines are growth inhibited when treated with 1,25(OH)2D3 (reviewed in Blutt and Weigel, 1999). The mechanism of action of these growth inhibitory effects of 1,25(OH)2D3 in LNCaP cells involves G1 accumulation, induction of quiescence, and an increase in apoptosis of the cancer cells (Blutt et al, 1997, 2000a; Zhuang and Burnstein, 1998). In vivo, 1,25(OH)2D3 and its analogs slow tumor growth and hinder metastasis of prostate tumors in rodent models (Schwartz et al, 1995; Getzenberg et al, 1997; Lokeshwar et al, 1999; Blutt et al, 2000b), and 1,25(OH)2D3 may have clinically relevant effects (Gross et al, 1998). More work is required to elucidate the mechanism of 1,25(OH)2D3 action in prostate cancer cells and to identify optimal 1,25(OH)2D3 analogs in a search for compounds with a better separation of growth inhibitory effects from hypercalcemic effects.