**4.4 Clinical studies in prostate cancer**

A review on clinical trials of resveratrol has already been recently published (Patel et al., 2011), and will not be discussed in detail here. Selected prostate cancer trials are listed in Table 3.

Resveratrol dosing studies have been performed at up to 5 grams per day. However, mild gastrointestinal side effects (abdominal pain, nausea, diarrhea) were common in subjects administered resveratrol at a dose 1g daily (Brown et al., 2010; Elliott et al., 2009; la Porte et al, 2010). A Phase I study of resveratrol in 10 volunteers demonstrated that even at the highest 5 g per day cohort, saturation kinetics were not observed (Boocock et al., 2007) and that plasma concentrations remained quite low, 500 ng/mL. This possibly is considerably less that the 5uM concentration required for *in vitro* activity, but six plasma and urine metabolites were identified; whether these compounds contribute to the anticancer activity of resveratrol remains unknown. Two monoglucuronide metabolites of resveratrol area under the curve concentrations were 23-fold hold higher than that of cis-resveratrol (Boocock et al., 2007). Inter-individual pharmacokinetic variability has been found to be high (Almeida et al., 2009). Complicating the picture is that other phytochemicals ingested in the diet, such as quercetin and to a lesser degree, kaempferol, fisetin, apigenin and myricetin, may inhibit phenol sulfotransferase and in doing so, increase resveratrol absorption (de Santi et al., 2000 a, b).

As the studies in Table 3 have noted, data for resveratrol are not all favourable or particularly convincing. The reasons are not well understood, but could include ineffective plasma concentrations derived from inadequate doses, inter-individual pharmacokinetic

Resveratrol results in dose-dependent inhibition of PI3K and pAkt in LNCaP cells that in turn modulates anti-apoptotic bcl2 family proteins (Aziz et al., 2006). Resveratrol reduces ERK 1/2 activation in PC3 cells (Stewart & O'Brian, 2004) amongst many other targets; some of these are listed in Table 2. For example, resveratrol also reduces the activity of clusterin by functioning as a tyrosine kinase inhibitor (Sallman et al., 2007), phosphoAkt and mTOR (Chen et al., 2010), and NFkB (Benitez et al., 2009). Resveratrol causes growth inhibition in typical prostate cancer cell lines: PC-3, DU145, and LNCaP (Hsieh & Wu, 1999), but interestingly, whole cranberry extract (containing resveratrol) was also effective in inducing apoptosis (Maclean et al., 2011). As in all whole-food extract studies, however, there is no certainty that the molecule of interest is responsible

In a PC3 xenograft study, resveratrol alone inhibited tumour growth, enhanced TRAIL induced apoptosis, and inhibited angiogenenesis (Ganapathy et al., 2010). Resveratrol is also able to reduce or delay prostate cancer in the TRAMP mouse model (Slusarz et al., 2010), possibly via inhibition of HedgeHog signaling. Conflicting evidence was provided by Wang et al., (2008), who found that resveratrol increased angiogenesis and inhibited apoptosis, at

A review on clinical trials of resveratrol has already been recently published (Patel et al., 2011), and will not be discussed in detail here. Selected prostate cancer trials are listed in

Resveratrol dosing studies have been performed at up to 5 grams per day. However, mild gastrointestinal side effects (abdominal pain, nausea, diarrhea) were common in subjects administered resveratrol at a dose 1g daily (Brown et al., 2010; Elliott et al., 2009; la Porte et al, 2010). A Phase I study of resveratrol in 10 volunteers demonstrated that even at the highest 5 g per day cohort, saturation kinetics were not observed (Boocock et al., 2007) and that plasma concentrations remained quite low, 500 ng/mL. This possibly is considerably less that the 5uM concentration required for *in vitro* activity, but six plasma and urine metabolites were identified; whether these compounds contribute to the anticancer activity of resveratrol remains unknown. Two monoglucuronide metabolites of resveratrol area under the curve concentrations were 23-fold hold higher than that of cis-resveratrol (Boocock et al., 2007). Inter-individual pharmacokinetic variability has been found to be high (Almeida et al., 2009). Complicating the picture is that other phytochemicals ingested in the diet, such as quercetin and to a lesser degree, kaempferol, fisetin, apigenin and myricetin, may inhibit phenol sulfotransferase and in doing so, increase resveratrol

As the studies in Table 3 have noted, data for resveratrol are not all favourable or particularly convincing. The reasons are not well understood, but could include ineffective plasma concentrations derived from inadequate doses, inter-individual pharmacokinetic

**4.2** *In vitro* **data** 

for the effect seen.

least in LNCaP xenografts.

**4.4 Clinical studies in prostate cancer** 

absorption (de Santi et al., 2000 a, b).

**4.3** *In vivo* **data** 

Table 3.


Dietary Manipulation for Therapeutic Effect in Prostate Cancer 299

IGF-1 and COX-2 gene expression did not change compared to placebo in men with early stage, low grade

One patient (5%) with complete response, 6 with partial response (30%)

Regression slopes of (log) PSA

26/37 (70%, 95% CI: 53–84%) of

and in eight cases (21%) the

No toxicity, but reduced serum free testosterone and increased total estradiol was noted.

Mean plasma concentration was 3.9, 7.4, 23.1 and 63.8 ng/mL and peaked in 0.8-1.5 hours post dose: Mean area under curve for plasma, post the 13th dose was 3.1, 11.2, 33.0 and 78.9 ng/mL; coefficients of variation

Adverse events were mild and similar between groups, but low plasma concentrations achieved

6/8 has loose stool or mild diarrhea at the start of the study 1 subject developed rash and

Mild adverse events experience d; low plasma concentrations

Decrease in inflammatory

 IL-6, high sensitivity CRP, intercellular adhesion molecule-1 (ICAM-1), monocyte chemo attractant protein 1 (MCP-1)

Phase I "did not cause discomfort" (Wong et al.,

(Chan et al., 2011)

(Ansari & Gupta,2004)

(Barber et al., 2006)

(Kumar et al., 2008)

(Almeida, et al.,

(la Porte et al., 2010)

(Almeida , 2009)

(Soleas et al., 2002)

2010)

2009)

prostate cancer.

vs time decreased in

the patients after supplementation

post-treatment slope was negative

>40%

headache

achieved

markers:

Intervention / Diet Design Outcome Reference

N = 69 (22 on lycopene, 21 on fish oil, 26 placebo). Randomized, Phase II double-blind

N=20, metastatic hormone refractory prostate cancer

cancer on surveillance

N=45, randomized to one of 3 doses of lycopene prior to prostatectomy

Double blind, randomized, placebo controlled Healthy volunteers, N=40, as 4 x 10 per

N=8 Healthy subjects Steady state and pharmacokinetics study Tolerability with food, quercetin and alcohol

N=8 Healthy volunteers

4 men, one per dosing

Healthy volunteers

group 5 males Phase I

Phase I

Phase I

Phase I

N=19

level

Double blind Randomized Placebo-controlled

trial.

10mg daily N=41, localized prostate

3 months of 30mg lycopne per day, 3g fish oil per day, or placebo

10mg daily for 3 months

15mg, 30mg, or 45mg for

Trans-resveratrol at: 0, 25,50,100 and 150 mg, 6 times/d for 13 doses-

2 g resveratrol BID over 8

Up to 975 mg/d as: 25,50,100,150 mg given 6 times per day over 2 days

28 day x 36 µg resveratrol per day- as Chardonnay cava wine containing *trans*-resveratrol, *cis*resveratrol, and *cis*-piceid

270 mg/d resveratrol

over 7 days

30 days

days

**Resveratrol** 


Non – significant decline in testosterone levels, but compensated rise in LH levels

Decline of PSA (not significant) of 14% while on high soy diet

No changes in sex hormones or

Regression modeling showed slowing of the rate of PSA rise, from 56% per year to 20% per

expression were reduced by soy isoflavones. Statistically significant correlation between isoflavone levels and p21 mRNA expression in the treatment group.


 Endpoints included PSA progression rate, QOL, analgesic use. Stable PSA noted

in 29%, but otherwise

Mean Plasma lycopene concentration 0.74 to 1.43 µmol/L (P<0.0001),

Mean Prostate tissue lycopene 0.45 to 0.59 pmol/mg. No significant changes in 8-oxodeoxyguanosine or malondialdehyde was seen.

activity.

no benefit.

95% of patients in lycopene group and 67% of patients in the combined group achieved PSA

stabilization.

PSA over 12 weeks

year while on study

Tissue COX-2 mRNA

(Rannikko et al.,

(Maskarinec et al., 2006)

(Vaishampayan et al., 2007)

(Kumar et al., 2007)

(Pendleton et al.,

(Swami et al., 2009)

(Dalais et al., 2004)

(Schwenke, et al., 2009)

(van Breemen et al., 2011) 

2008)

2006)

Intervention / Diet Design Outcome Reference

N=20, pilot study, placebo controlled.

N=24, randomized crossover to alternative diet after 1 month

N=71, includes hormone sensitive and resistant patients. Randomized

N=50 men with prostate cancer Gleason grad 6 or

treatment. Randomized, placebo controlled, double blind

N=20, open label study observing rate of PSA rise after local therapy

N=25 (12 placebo, 13 soy). Randomized, double blind, placebo

N=29, Pilot study. randomized comparison prior to prostatectomy

N=18, Phase II pilot study in men with advanced hormone refractory disease. 29% withdrew from the study before the end of the 6 month observation period.

N=105. Randomized Phase II, placebo controlled, double blind study in African Americans. 21 day treatment prior to prostate biopsy.

controlled

less completed

washout

trial.

240mg clover

months

months

isoflavones

12 months

Soy isoflavone supplement for 2 -4 weeks prior to prostatectomy

**Lycopene** 

6 months

phytoestrogens daily for 2 weeks prior to prostatectomy

High or low soy diet for 3

Lycopene with or without soy isoflavones for 6

80mg daily, purified

Soy milk 3 times daily for

Soy vs Soy + linseed vs wheat in bread diet

15 mg Lycopene daily for

30 mg/d lycopene supplement tomato oleoresin (LycoRed®)


Dietary Manipulation for Therapeutic Effect in Prostate Cancer 301

bioavailability (Anand et al., 2007). Absorption and transformation occurs at the intestinal wall, where enzymes such as sulfotransferases, UDP-glucoronyltransferase, and P450 ensure its rapid breakdown (Ireson et al., 2002). Pharmacokinetic studies, including Phase I and other trials confirm the poor bioavailability of the compound (Cheng et al, 2001; Sharma et al., 2004; Garcea et al., 2005; Garcea et al., 2004). Data from these studies show that curcumin seems to be absorbed from the gut within 1-2hrs, and doses up to 8000mg have produced minimal toxicity. Nausea and diarrhea have been the principal toxicities encountered. Vareed et al (2008) studied doses of either 10g or 12g in volunteers, and found Cmax to be around 1.7-2.3 ug/mL, with time taken to reach maximum concentration (Tmax) and halflife estimated to be 3.3h and 6.8h, respectively. Sharma et al., (2004) studied escalating doses in a Phase I trial up to 3.6g daily and found no dose-limiting toxicity. Mild nausea and diarrhea was encountered, but plasma concentrations of only around 10nM could be elicited in this study; nevertheless, inducible PGE2 production was reduced by about 50-60% at that

There is a wealth of literature on the potential mechanism of action of curcumin *in vitro* (see Table 2), but it is not clear which is the predominant mode of action. It is highly likely that different mechanisms of action exist for different cell lines. Curcumin can inhibit Akt and mTOR in PC3 cell lines (Yu et al., 2008), and enhance Apo2L/TRAIL induced apoptosis, at least in ovarian cancer cells (Wahl et al., 2007). EF24, a curcumin analogue, and curcumin itself can inhibit HIF1alpha gene transcription in PC3 prostate cancer cells (Thomas et al., 2008). Teiten et al., (2011) showed that curcumin induced cell cycle arrest in G2 phase and could modulate Wnt signaling in androgen-dependent prostate cancer cells, but not in

Apoptotic and growth inhibitory pathways are affected by curcumin in numerous ways (Ravindran et al., 2009). One example is its ability to abrogate survival mechanisms via suppression of constitutive and inducible NF-kappaB activation (Mukhopadhyay et al., 2001). It can also induce apoptosis of DU145 and LNCaP, associated with reduction of

Curcumin inhibits LNCaP xenograft growth, induces apoptosis, and sensitizes tumours to TRAIL induced apoptosis (Shankar et al., 2007). Others have also demonstrated the growth inhibitory properties of curcumin *in vivo* (Barve et al., 2008; Khor et al., 2006), possibly via antiangiogenic mechanisms such as reduction of MMP-2 and MMP-9 expression (Hong et al., 2006). Liposomal encapsulation of curcumin, particularly in combination with resveratrol, significantly reduces prostate cancer tumours *in vivo* (Narayanan et al., 2009).

Despite the intense interest in curcumin as a possible cancer prevention agent, there is a surprising lack of clinical data in prostate cancer. Efforts have focused on improving bioavailability by incorporating curcumin in nanoparticles, or developing more potent analogues. Whilst ongoing trials in prostate cancer are yet to be reported, the only trial we

dose level.

**5.2** *In vitro* **data** 

**5.3** *In vivo* **data** 

**5.4 Clinical studies** 

androgen-independent cells.

expression of Bcl2 and bcl-xL (Mukhopadhyay et al., 2001).


Table 3. Selected clinical trials of phytochemicals in prostate cancer.

and pharmacodynamic variability, and other factors such as drug interaction. For example, resveratrol has been shown to inhibit cytochrome P 450; 3A4, 2D6, 2C9 and alternately induce 1A2 (Chow et al., 2010), a key factor that has not been taken into account in many clinical studies. Theoretically, interactions with concomitant medications whilst on trial may therefore result in either unwanted toxicity or reduced concentrations of resveratrol.
