Curcumin Combined with FOLFOX Chemotherapy Is Safe and Tolerable in Patients with Metastatic Colorectal Cancer in a Randomized Phase IIa Trial.

BACKGROUND: Curcumin is the main active ingredient of the spice turmeric, investigated extensively for putative anticancer properties. OBJECTIVES: This phase IIa open-labelled randomized controlled trial aimed to assess safety, efficacy, quality of life, neurotoxicity, curcuminoids, and C-X-C-motif chemokine ligand 1 (CXCL1) in patients receiving folinic acid/5-fluorouracil/oxaliplatin chemotherapy (FOLFOX) compared with FOLFOX + 2 g oral curcumin/d (CUFOX). METHODS: Twenty-eight patients aged >18 y with a histological diagnosis of metastatic colorectal cancer were randomly assigned (1:2) to receive either FOLFOX or CUFOX. Safety was assessed by Common Toxicity Criteria-Adverse Event reporting, and efficacy via progression-free survival (PFS) and overall survival (OS). Quality of life and neurotoxicity were assessed using questionnaires (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30 and Functional Assessment of Cancer Treatment-Gynecologic Oncology Group-Neurotoxicity). Plasma curcuminoids were determined with liquid chromatography (LC) electrospray ionization tandem mass spectrometry and CXCL1 by ELISA. RESULTS: Addition of daily oral curcumin to FOLFOX chemotherapy was safe and tolerable (primary outcome). Similar adverse event profiles were observed for both arms. In the intention-to-treat population, the HR for PFS was 0.57 (95% CI: 0.24, 1.36; P = 0.2) (median of 171 and 291 d for FOLFOX and CUFOX, respectively) and for OS was 0.34 (95% CI: 0.14, 0.82; P = 0.02) (median of 200 and 502 d for FOLFOX and CUFOX, respectively). There was no significant difference between arms for quality of life (P = 0.248) or neurotoxicity (P = 0.223). Curcumin glucuronide was detectable at concentrations >1.00 pmol/mL in 15 of 18 patients receiving CUFOX. Curcumin did not significantly alter CXCL1 over time (P = 0.712). CONCLUSION: Curcumin is a safe and tolerable adjunct to FOLFOX chemotherapy in patients with metastatic colorectal cancer. This trial was registered at clinicaltrials.gov as NCT01490996 and at www.clinicaltrialsregister.eu as EudraCT 2011-002289-19.

Curcumin inhibits cancer stem cell phenotypes in ex vivo models of colorectal liver metastases, and is clinically safe and tolerable in combination with FOLFOX chemotherapy.

In vitro and pre-clinical studies have suggested that addition of the diet-derived agent curcumin may provide a suitable adjunct to enhance efficacy of chemotherapy in models of colorectal cancer. However, the majority of evidence for this currently derives from established cell lines. Here, we utilised patient-derived colorectal liver metastases (CRLM) to assess whether curcumin may provide added benefit over 5-fluorouracil (5-FU) and oxaliplatin (FOLFOX) in cancer stem cell (CSC) models. Combination of curcumin with FOLFOX chemotherapy was then assessed clinically in a phase I dose escalation study. Curcumin alone and in combination significantly reduced spheroid number in CRLM CSC models, and decreased the number of cells with high aldehyde dehydrogenase activity (ALDH(high)/CD133(-)). Addition of curcumin to oxaliplatin/5-FU enhanced anti-proliferative and pro-apoptotic effects in a proportion of patient-derived explants, whilst reducing expression of stem cell-associated markers ALDH and CD133. The phase I dose escalation study revealed curcumin to be a safe and tolerable adjunct to FOLFOX chemotherapy in patients with CRLM (n = 12) at doses up to 2 grams daily. Curcumin may provide added benefit in subsets of patients when administered with FOLFOX, and is a well-tolerated chemotherapy adjunct.

Combining curcumin (C3-complex, Sabinsa) with standard care FOLFOX chemotherapy in patients with inoperable colorectal cancer (CUFOX): study protocol for a randomised control trial.

BACKGROUND: The need for low toxicity adjuncts to standard care chemotherapy in inoperable colorectal cancer, with potential to improve outcomes and decrease the side-effect burden, is well recognised. Addition of the low toxicity diet-derived agent, curcumin (the active ingredient of turmeric), to standard oxaliplatin-based therapy has shown promise in numerous pre-clinical studies. METHODS/DESIGN: This study is the first to combine daily oral curcumin with standard care FOLFOX-based (5-fluorouracil, folinic acid and oxaliplatin) chemotherapy in colorectal cancer patients with inoperable liver metastases: the CUFOX trial. CUFOX comprises a Phase 1 dose-escalation study (3 + 3 + 3 design) to determine an acceptable target dose of curcumin with which to safely proceed to a Phase IIa open-labelled randomised controlled trial. Thirty three participants with histological or cytological confirmation of inoperable colorectal cancer will then be randomised to oxaliplatin-based chemotherapy with the addition of daily oral curcumin at the target dose determined in Phase I, or to standard care oxaliplatin-based chemotherapy alone (recruiting at a ratio of 2:1). DISCUSSION: Primary outcome measures will be the determination of a target dose which is both safe and tolerable for long-term administration to individuals in receipt of first-line oxaliplatin-based chemotherapy for inoperable colorectal cancer. Secondary outcome measures will include observation of any changes in neuropathic side-effects of chemotherapy, improvement to progression-free or overall survival and identification of putative efficacy biomarkers in plasma. The results will be disseminated via presentation at national and international conferences, via publication in appropriate peer-reviewed journals and via the Cancer Research UK/Department of Health Experimental Cancer Medicine Centre Network. This trial has full ethical and institutional approval, and commenced recruitment in February 2012. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT01490996 , registered 7(th) December 2011), European Drug Regulating Authorities (EudraCT 2011-002289-19, registered 13(th) May 2011), UKCRN ID#10672.

Translating curcumin to the clinic for lung cancer prevention: evaluation of the preclinical evidence for its utility in primary, secondary, and tertiary prevention strategies.

Lung cancer is responsible for over one million deaths worldwide each year. Smoking cessation for lung cancer prevention remains key, but it is increasingly acknowledged that prevention strategies also need to focus on high-risk groups, including ex-smokers, and patients who have undergone resection of a primary tumor. Models for chemoprevention of lung cancer often present conflicting results, making rational design of lung cancer chemoprevention trials challenging. There has been much focus on use of dietary bioactive compounds in lung cancer prevention strategies, primarily due to their favorable toxicity profile and long history of use within the human populace. One such compound is curcumin, derived from the spice turmeric. This review summarizes and stratifies preclinical evidence for chemopreventive efficacy of curcumin in models of lung cancer, and adjudges the weight of evidence for use of curcumin in lung cancer chemoprevention strategies.

Dietary intake of rosmarinic acid by Apc(Min) mice, a model of colorectal carcinogenesis: levels of parent agent in the target tissue and effect on adenoma development.

SCOPE: Rosmarinic acid (RA), a constituent of culinary herbs is considered to possess cancer chemopreventive properties. It has been shown to inhibit the development of cancer in preclinical models but data are conflicting and whether it can protect against gastrointestinal malignancies in vivo has not been examined. This study aimed to investigate the effect of RA on the development of intestinal adenomas in the Apc(Min) mouse model of colorectal carcinogenesis, and to correlate efficacy with levels of RA achieved in the plasma and gastrointestinal tract. METHODS AND RESULTS: RA inhibited the growth of APC10.1 cells derived from Apc(Min) mouse adenomas, with an IC50 of 43 µM. Consumption of dietary RA (0.3%) by Apc(Min) mice for 8 weeks post weaning decreased adenoma burden by ∼35%, but the difference from controls was not significant. Although RA significantly decreased the frequency of large adenomas, the number of small ones increased. Using a novel validated HPLC assay, average levels of RA in the plasma and intestinal mucosa of these mice were found to be 1.1 µM and 38 nmol/g, respectively. CONCLUSION: Chronic consumption of RA furnished quantifiable levels of parent compound in the plasma and intestinal tract of Apc(Min) mice and may slow adenoma development.

Resveratrol in human cancer chemoprevention--choosing the 'right' dose.

There is now robust preclinical evidence to suggest that resveratrol possesses cancer chemopreventive properties. A series of clinical pilot studies has provided insights into its pharmacokinetics, and data on its human antineoplastic pharmacodynamics start to emerge. It is likely that resveratrol will be developed further in the clinic as a putative cancer chemopreventive agent. The question that remains unresolved is: What is the most suitable dose of resveratrol for effective cancer preventive intervention? Mechanistic studies in cells in vitro have almost invariably used concentrations of resveratrol in the 10(-5) to 10(-4) M range, which is much higher than those which can be achieved in the human biophase after consumption of doses up to 1 g. Many of the preclinical efficacy studies in rodent models of carcinogenesis have employed doses which are dramatically above those which can be ingested with the diet. New experimental paradigms need to be used to obtain information on pharmacological changes elicited by resveratrol when present at very low concentrations or when administered at dietary-relevant doses.

Curcumin: the potential for efficacy in gastrointestinal diseases.

Curcumin is a naturally occurring phytochemical and an extract of turmeric. Extensive in vitro and in vivo data have paved the way for curcumin to become the subject of clinical trials. Curcumin modulates key signalling pathways important in cellular processes. Numerous mechanisms of action have been elucidated. The potential for clinical efficacy is apparent from benign and malignant disease models. Curcumin has potent anti-inflammatory and anti-neoplastic properties used alone and in combination with standard therapies. Early-phase trials have ascertained pharmacological properties and consistently demonstrate it to be safe and well tolerated. However, bioavailability is limited and efficacious doses have not yet been determined. Evidence of efficacy has been derived from animal models or small clinical trials. There is only finite data supporting the use of curcumin in phase III trials with specific diseases (e.g. ulcerative colitis). However, for the vast majority of conditions additional early-phase studies are required to justify larger trials determining efficacy.

Curcumin ameliorates oxaliplatin-induced chemoresistance in HCT116 colorectal cancer cells in vitro and in vivo.

The aims of this study were to determine potency of oxaliplatin in combination with curcumin in oxaliplatin-resistant cell lines in vitro and to evaluate the efficacy of a novel curcumin formulation (Meriva®) alone and in combination with oxaliplatin in colorectal tumor-bearing mice, exploring relevant pharmacodynamic markers in vivo. Oxaliplatin-resistant HCT116 p53wt and p53(-/-) cell lines were generated, and the effects of oxaliplatin in combination with curcumin on resistance- and proliferation-associated proteins investigated. Eighty nude mice were implanted with HCT116 p53wt colorectal cancer cells before randomization into the following treatment groups: control; Meriva only; oxaliplatin only; Meriva + oxaliplatin. Tumor volume was assessed, as was the expression of Ki-67, cleaved caspase-3 and Notch-1. Curcumin in combination with oxaliplatin was able to decrease proliferative capacity of oxaliplatin-resistant p53 wildtype and p53(-/-) cell lines more effectively than oxaliplatin alone. It also decreased markers associated with proliferation. After 21 days of treatment in the xenograft model, the order of efficacy was combination > Meriva > oxaliplatin > control. The decrease in tumor volume when compared to vehicle-treated animals was 53, 35 and 16%, respectively. Ki-67 and Notch-1 immunoreactivity was decreased by the combination when compared to vehicle-treated animals, with cleaved caspase-3 rising by 4.4-fold. Meriva did not adversely affect the DNA-platinating ability of oxaliplatin. Curcumin enhanced the cytotoxicity of oxaliplatin in models of oxaliplatin resistance in vitro. In vivo, Meriva greatly enhanced oxaliplatin efficacy, without affecting the mode of action of oxaliplatin. Addition of formulated curcumin to oxaliplatin-based chemotherapy regimens has the potential for clinical benefit.

Determination of anthocyanins in the urine of patients with colorectal liver metastases after administration of bilberry extract.

Anthocyanins possess cancer chemopreventive properties in preclinical models. Their clinical pharmacology is only poorly understood. In this pilot study, anthocyanins and their metabolites were analysed in the urine of two patients with colorectal liver metastases. They received a single dose of 1.88 g standardized bilberry extract (mirtoselect) via either nasogastric or nasojejunal tube intra-operatively during liver resection. HPLC-MS/MS and HPLC-UV analysis showed there were more anthocyanins and metabolites in the urine of the patient who received mirtoselect via the stomach than via the jejunum. This result is consistent with information obtained in rodents which suggests the stomach is the predominant site for anthocyanin absorption.

Preclinical colorectal cancer chemopreventive efficacy and p53-modulating activity of 3',4',5'-trimethoxyflavonol, a quercetin analogue.

Some naturally occurring flavonols, exemplified by quercetin, seem to possess experimental cancer chemopreventive efficacy. Modulation of p53 is a mechanism thought to contribute to their activity. The hypothesis was tested that a synthetic flavonol, 3',4',5'-trimethoxyflavonol (TMFol), can interfere with tumor development and p53 expression in two models of colorectal carcinogenesis, Apc(Min) mice and human-derived HCT116 adenocarcinoma-bearing nude mice. Mice received TMFol with their diet (0.2%) from weaning to week 16 in the case of Apc(Min) or from either day 7 before ("TMFol early") or day 7 after ("TMFol late") tumor inoculation in HCT116 mice. The ability of TMFol to affect tumor proliferation or apoptosis, as reflected by staining for Ki-67 or cleaved caspase-3, respectively, was studied in HCT116 tumors. TMFol tumor levels were measured by high-performance liquid chromatography. Consumption of TMFol reduced small intestinal adenoma burden in Apc(Min) mice by 47%, compared with control mice (P < 0.002). The TMFol early regimen approximately halved HCT116 tumor size (P < 0.05), decreased tumor proliferation, and increased apoptosis, whereas the TMFol late regimen had no significant effect when compared with controls. In tumor tissues from mice, in which TMFol reduced tumor development, p53 expression was increased 3-fold in Apc(Min) and 1.5-fold in HCT116 tumor-bearing mice (P = 0.02). TMFol increased p53 also in cells derived from these tumors. TMFol was detected in HCT116 tumors, but levels did not correlate with tumor burden. TMFol was not mutagenic in the Ames test. The results suggest that chemical modification of the flavonol structure may generate safe and efficacious cancer chemopreventive agents.

Plasma metabolic profiling reveals age-dependency of systemic effects of green tea polyphenols in mice with and without prostate cancer.

Green tea polyphenols (GTP) have been widely investigated for their potential to prevent prostate cancer. However, results from epidemiological and clinical studies are equivocal. Studies in the TRAMP (TRansgenic Adenocarcinoma of the Mouse Prostate) mouse suggest that the chemopreventive efficacy of GTP is higher in young animals with early stages of carcinogenesis than in old ones. Here, effects of GTP on prostate carcinogenesis in TRAMP mice were assessed by comparing pathological changes with (1)H-NMR metabolic profiling of plasma and extracts of prostate tissue. Mice received 0.05% GTP in their drinking water for 4 or 25 weeks after weaning. Age-matched wild-type mice were included in the study in order to establish differences in GTP effects between normal and TRAMP mice. Dietary GTP did not markedly alter prostate carcinogenesis as reflected by pathology and prostate tissue metabolic profile. However, a systemic effect of GTP consumption was observed in young mice, regardless of genotype. Plasma lipid signals were decreased in 8 week old mice which received GTP compared to age-matched controls by 19, 61, 27, 34 and 15% (p

Anthocyanin-rich red grape extract impedes adenoma development in the Apc(Min) mouse: pharmacodynamic changes and anthocyanin levels in the murine biophase.

PURPOSE: Red grape pomace extract (oenocyanin) is a cheap and rich source of anthocyanins, the agents suggested to possess cancer chemopreventive properties. Here the hypothesis was tested that oenocyanin added to the diet can interfere with intestinal adenoma development in the Apc(Min) mouse, a model of intestinal carcinogenesis linked to an Apc mutation. METHODS: Mice received oenocyanin (0.3%) in their diet until week 16, when adenoma number and burden were recorded. Expression of Akt and ERK proteins was studied by Western blot in adenomas to discover effects of anthocyanins on cellular signalling via the PI3 and MAP kinase pathways. Levels of anthocyanins were measured by HPLC with visible spectroscopic or mass spectrometric detection. RESULTS: In mice which had consumed oenocyanin, overall adenoma burden was halved and adenoma number was marginally reduced when compared with mice on control diet. The proliferation index in colonic adenomatous crypts, as reflected by Ki-67 staining, was significantly decreased from 88.14% in control mice to 75.6+/-4% in mice on oenocyanin (P=0.014). Expression of Akt in small intestinal adenomas from Apc(Min) mice on oenocyanin was reduced by 54% (P=0.003), when compared to controls. Oenocyanin anthocyanins and glucuronide metabolites were found in the urine and intestine but not in plasma. CONCLUSIONS: The results suggest that oenocyanin may be a viable and economical alternative to anthocyanin-rich berry extracts for chemopreventive intervention. Akt and pErk might be suitable biomarkers of anthocyanin target organ efficacy.

APC10.1 cells as a model for assessing the efficacy of potential chemopreventive agents in the Apc(Min) mouse model in vivo.

Apc(Min) mice are widely used for mechanism and efficacy studies associated with the development of chemopreventive agents. APC10.1 cells have been derived from Apc(Min) mouse adenomas and retain the heterozygous Apc genotype. We tested the hypothesis that this cell type may provide an in vitro model to predict chemopreventive activity of agents in the Apc(Min) mouse in vivo. The growth inhibitory properties of 14 putative colorectal cancer chemopreventive agents, tricin, apigenin, 3',4',5',5,7-pentamethoxyflavone, resveratrol, curcumin, 3,4-methylenedioxy-3',4',5'-trimethoxychalcone (DMU135), 3,4,5,4'-tetramethoxystilbene (DMU212), celecoxib, aspirin, piroxicam, all-trans-retinoic acid, difluoromethylornithine (DFMO), quercetin and cyanidin-3-glucoside, were studied in this cell line, and the IC(50) values were calculated. The IC(50) values were plotted against previously published data of reduction of adenoma numbers caused by these agents in Apc(Min) mice. The correlation co-efficient was 0.678 (p<0.01), suggesting that there was a tentative correlation between the ability to inhibit the growth of APC10.1 cells and the ability to delay adenoma development in vivo. If this relationship is supported by using further agents, APC10.1 cells may serve in the future as an initial screen to prioritise compounds for assessing chemopreventive efficacy in Apc(Min) mice in vivo. Such a screen could reduce the number of animals required to find active agents, help reduce costs and increase throughput.

Flavones as colorectal cancer chemopreventive agents--phenol-o-methylation enhances efficacy.

Flavonoids occur ubiquitously in plants, and some possess preclinical cancer chemopreventive activity. Little is known about molecular features that mediate chemopreventive efficacy of flavonoids. Here, three related flavones, apigenin (4',5,7-trihydroxyflavone), tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone), and 3',4',5',5,7-pentamethoxyflavone (PMF), were compared in terms of their effects on (a) adenoma development in Apc(Min) mice, a model of human gastrointestinal malignancies; (b) growth of APC10.1 mouse adenoma cells in vitro; and (c) prostaglandin E-2 generation in HCA-7 human-derived colorectal cancer cells in vitro. Life-long consumption of PMF with the diet at 0.2% reduced Apc(Min) mouse adenoma number and burden by 43% and 61%, respectively, whereas apigenin was inactive. Tricin has previously shown activity in this model. IC50 values for murine adenoma cell growth inhibition by PMF, tricin, and apigenin were 6, 13, and 18 micromol/L, respectively. In Apc(Min) mice that received flavones (0.2%) for 4 weeks, adenoma cell proliferation as reflected by Ki-67 staining was reduced by PMF and tricin, but not by apigenin. On incubation with HCA-7 cells for 6 hours, PMF reduced prostaglandin E-2 generation with an IC50 of 0.8 micromol/L, a fraction of the respective values reported for tricin or apigenin. In silico PMF docked into the cyclooxygenase active site with greater affinity than tricin or apigenin. The results suggest that the rank order of cancer chemopreventive efficacy in Apc(Min) mice is PMF > tricin > apigenin, supporting the notion that the presence of O-methyl in the flavone molecular scaffold promotes gastrointestinal cancer chemopreventive efficacy.

Pilot study of oral anthocyanins for colorectal cancer chemoprevention.

Naturally occurring anthocyanins possess colorectal cancer chemopreventive properties in rodent models. We investigated whether mirtocyan, an anthocyanin-rich standardized bilberry extract, causes pharmacodynamic changes consistent with chemopreventive efficacy and generates measurable levels of anthocyanins in blood, urine, and target tissue. Twenty-five colorectal cancer patients scheduled to undergo resection of primary tumor or liver metastases received mirtocyan 1.4, 2.8, or 5.6 grams (containing 0.5-2.0 grams anthocyanins) daily for 7 days before surgery. Bilberry anthocyanins were analyzed by high performance liquid chromatography (HPLC) with visible or mass spectrometric detection. Proliferation was determined by immunohistochemistry of Ki-67 in colorectal tumor. Concentrations of insulin-like growth factor (IGF)-I were measured in plasma. Mirtocyan anthocyanins and methyl and glucuronide metabolites were identified in plasma, colorectal tissue, and urine, but not in liver. Anthocyanin concentrations in plasma and urine were roughly dose-dependent, reaching approximately 179 ng/gram in tumor tissue at the highest dose. In tumor tissue from all patients on mirtocyan, proliferation was decreased by 7% compared with preintervention values. The low dose caused a small but nonsignificant reduction in circulating IGF-I concentrations. In conclusion, repeated administration of bilberry anthocyanins exerts pharmacodynamic effects and generates concentrations of anthocyanins in humans resembling those seen in Apc(Min) mice, a model of FAP adenomas sensitive to the chemopreventive properties of anthocyanins. Studies of doses containing <0.5 gram bilberry anthocyanins are necessary to adjudge whether they may be appropriate for development as colorectal cancer chemopreventive agents.

Development of dietary phytochemical chemopreventive agents: biomarkers and choice of dose for early clinical trials.

In view of safety concerns surrounding the use of pharmaceuticals such as nonsteroidal anti-inflammatory drugs and tamoxifen as cancer chemopreventive agents, potentially innocuous phytochemicals derived from the diet are considered attractive alternatives. However, results from cancer chemoprevention trials of dietary agents have been disappointing to date, as promising activities observed in rodent models and cells in vitro have not translated into clinical success. This may be partly due to the development process for these agents, which is complex for a number of reasons; the definitive end point, inhibition of carcinogenesis, requires large numbers of individuals followed-up over many years. Furthermore, whereas biomarkers are frequently used as surrogate efficacy end points to expedite the process, biomarker assessment and validation has proven difficult because dietary agents exert multiple actions with an unknown hierarchy of biological importance. These factors have made determining the dose for clinical investigation extremely challenging, and at present, there are no defined strategies for rationally identifying the most appropriate doses. In this commentary, the complexities involved in the development of dietary chemoprevention agents are discussed, and a tentative route towards selection of the optimal clinical dose is proposed. The approach highlights the need to conduct long-term preclinical studies with realistic concentrations that are achievable in human tissues and the importance of efficacy biomarkers that are intrinsically linked to the key mechanisms of action. A more logical design of studies should increase the likelihood that the encouraging preclinical results observed for many phytochemicals translate into tangible clinical benefit.

Do anthocyanins and anthocyanidins, cancer chemopreventive pigments in the diet, merit development as potential drugs?

Anthocyanins, plant pigments in fruits and berries, have been shown to delay cancer development in rodent models of carcinogenesis, especially those of the colorectal tract. Anthocyanins and anthocyanidins, their aglycons, especially cyanidin and delphinidin, have been subjected to extensive mechanistic studies. In cells in vitro, both glycosides and aglycons engage an array of anti-oncogenic mechanisms including anti-proliferation, induction of apoptosis and inhibition of activities of oncogenic transcription factors and protein tyrosine kinases. Anthocyanins and anthocyanidins exist as four isomers, interconversion between which depends on pH, temperature and access to light. Anthocyanidins are much more prone to avid chemical decomposition than the glycosides, and they only survive for minutes in the biophase. These pharmaceutical issues are very important determinants of the suitability of these flavonoids for potential development as cancer chemopreventive drugs, and they have hitherto not received adequate attention. In the light of their robust cancer chemopreventive efficacy in experimental models and their superior stability as compared to that of the aglycons, the anthocyanins seem much more suitable for further drug development than their anthocyanidin counterparts.

Determination of 8-oxo-2'-deoxyguanosine and creatinine in murine and human urine by liquid chromatography/tandem mass spectrometry: application to chemoprevention studies.

Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) represents a non-invasive biomarker for oxidative stress and may be useful for monitoring chemotherapeutic and chemopreventive interventions associated with cancer-related alterations in oxidative stress. We describe the development and validation of two separate liquid chromatography/tandem mass spectrometry (LC/MS/MS) selected reaction monitoring (SRM) methods for the determination of 8-oxodG and creatinine in both murine and human urine using stable isotope labelled internal standards. Levels of 8-oxodG were normalised to creatinine. The LC/MS/MS methods were applied to two chemoprevention studies utilising tea polyphenols in humans and TRAMP (TRansgenic Adenocarcinoma of the Mouse Prostate) mice. Patients with benign prostatic hyperplasia received 1 g/day of green tea polyphenols (GTP), 1 g/day of black tea theaflavins (BTT) or no treatment for 4 weeks. TRAMP mice received GTP (0.05% in drinking water) for 4 or 25 weeks. Prostate pathology in TRAMP mice was not affected by GTP. Levels of 8-oxodG were not altered by tea polyphenols in either mice or humans. In TRAMP mice, urinary 8-oxodG levels were elevated with increasing age (p < 0.0001) but not changed by the presence of prostate tumours. In conclusion, the LC/MS/MS SRM methods described here are ideally suited for the accurate determination of 8-oxodG and creatinine in urine samples from both clinical and pre-clinical studies.

Evaluation of the cancer chemopreventive efficacy of silibinin in genetic mouse models of prostate and intestinal carcinogenesis: relationship with silibinin levels.

Silibinin, a flavonolignan from milk thistle seeds, possesses cancer chemopreventive properties in rodent models of carcinogenesis. We tested the hypotheses that silibinin or silipide, silibinin formulated with phospholipids, delays tumour development in TRAMP or Apc(Min) mice, genetic models of prostate or intestinal malignancies, respectively. Mice received silibinin or silipide with their diet (0.2% silibinin equivalents) from weaning. Intervention with silipide reduced the size of well differentiated TRAMP adenocarcinomas by 31%. Silipide and silibinin decreased the incidence of poorly differentiated carcinomas by 61% compared to mice on control diet. Silipide decreased plasma levels of insulin-like growth factor (IGF)-1 by 36%. Levels of circulating IGF binding protein (IGFBP)-3 in mice on silipide or silibinin were 3.9- or 5.9-fold, respectively, elevated over those in control TRAMP mice. In Apc(Min) mice silibinin, but not silipide, had only a marginal adenoma number-reducing effect. The results cautiously support the advancement of silipide to the stage of clinical investigation in prostate cancer.

Curcumin in cancer management: recent results of analogue design and clinical studies and desirable future research.

The ability of the curry constituent curcumin to delay the onset of cancer has been the topic of extensive research for many years. Abundant literature is devoted to mechanisms by which curcumin may mediate this activity. These insights have prompted investigations in which curcumin as lead molecule serves as a scaffold for synthetic chemical attempts to optimize pharmacological potency. Among the published analogues with notable efficacy are dimethylcurcumin, 1,5-bis(3-pyridyl)-1,4-pentadien-3-one and 3,5-bis-(2-fluorobenzylidene)-piperidinium-4-one acetate. Results of a small number of clinical pilot studies conducted with curcumin at doses of up to 12 g suggest tentatively that it is safe in humans. Prevention of adenoma recurrence constitutes a clinical paradigm worthy of further investigation for curcumin. Future clinical study should include measurement of mechanism-based pharmacodynamic parameters.