Lycopene and Vit E work together to fight prostate cancer

[Guest guest]

New study in Journal of Nutrition says lycopene and vitamin E work

synergistically to fight prostate cancer in mouse study. Each

compound given separately had little effect, but the two given

together reduced prostate tumors by 73%. Two articles with links and

full text below.

Dave

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http://jn.nutrition.org/cgi/content/abstract/136/5/1287

Combined Lycopene and Vitamin E Treatment Suppresses the Growth of PC-

346C Human Prostate Cancer Cells in Nude Mice

Limpens*, Fritz H. Schröder*, Corrina M. A. de Ridder*,

A. Bolder*, Mark F. Wildhagen*, Ute C. Obermüller-Jevic, Klaus

Krämer and Wytske M. van Weerden*,1

* Department of Urology, Erasmus MC, Rotterdam, The Netherlands and

BASF Aktiengesellschaft, Ludwigshafen, Germany

1 To whom correspondence should be addressed. E-mail:

w.vanweerden@....

Epidemiologic studies have repeatedly associated a high intake of

lycopene and vitamin E with reduced prostate cancer risk. The present

study examined the ability of the 2 compounds to reduce tumor growth

and prostate-specific antigen (PSA) plasma levels in the PC-346C

orthotopic mouse model of human prostate cancer. Three days after

intraprostatic tumor injection, NMRI nu/nu mice were administered a

daily oral dose of synthetic lycopene [5 or 50 mg/kg body weight

(BW)], vitamin E in the form of -tocopheryl acetate (5 or 50 mg/kg

BW), a mixture of lycopene and vitamin E (5 mg/kg BW each), or

vehicle. Intraprostatic tumor volume and plasma PSA concentrations

were measured at regular intervals. Mice were killed when the tumor

load exceeded 1000 mm3 or on d 95 when the study was terminated.

Prostate and liver were analyzed by HPLC for lycopene isomers and -

and , -tocopherol concentrations. None of the single treatments

significantly reduced tumor volume. In contrast, combined treatment

with lycopene and vitamin E, at 5 mg/kg BW each, suppressed

orthotopic growth of PC-346C prostate tumors by 73% at d 42 (P <

0.05) and increased median survival time by 40% from 47 to 66 d (P =

0.02). The PSA index (PSA:tumor volume ratio) did not differ between

experimental groups, indicating that PSA levels were not selectively

affected. Lycopene was detected only in mice supplemented with

lycopene. As in humans, most tissue lycopene was in the cis-isomer

conformation, whereas 77% trans-lycopene was used in the dosing

material. Liver -tocopherol concentrations were increased in mice

supplemented with both 50 mg/kg (226%, P < 0.05) and 5 mg/kg vitamin

E (41%, P < 0.05), whereas prostate -tocopherol concentrations were

increased only by the higher dose (83%, P < 0.05). Our data provide

evidence that lycopene combined with vitamin E may inhibit the growth

of prostate cancer and that PSA can serve as a biomarker of tumor

response for this treatment regimen.

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http://www.nutraingredients.com/news/ng.asp?

n=67083 & m=1NIE414 & c=lqeudkujayvvlpc

Prostate tumours shrunk by lycopene, vitamin E combo

14/04/2006- A combination of lycopene and vitamin E suppressed the

growth of prostate cancer in mice, but had no effect when used

independently, say Dutch researchers.

The role of tomato and its extracts to protect against prostate

cancer has been reported in several epidemiological studies, which

lycopene supplement producers have been quick to promote. The new

research, led by Professor Wytske van Weerden from Erasmus MC in

Rotterdam, casts doubt on the effectiveness of lycopene by itself,

and suggests a synergetic effect with vitamin E, another nutrient

naturally found in tomatoes.

The study, published in the May issue of the Journal of Nutrition

(Vol. 136, pp. 1287-1293), followed the effects on differing

supplementation doses and combinations of lycopene and vitamin E on

54 mice inoculated with prostate cancer cells.

The mice were divided into six equal groups. The mice were fed a

standard low vitamin E rodent diet, and three days after inoculation

the diet was supplemented with one of the following: nothing

(placebo); lycopene only (5 milligrams per kilogram of body weight

(mg/kg BW) or 50 mg/kg BW); vitamin E only (5 mg/kg BW or 50 mg/kg

BW); or vitamin E plus lycopene (5 mg/kg BW each).

BASF provided both nutrients: lycopene was provided as LycoVit 10 per

cent, and vitamin E as alpha-tocopherol 50 per cent powder.

The researchers found that, after 95 days of supplementation, none of

the single supplements, regardless of dose, had any effect on the

tumour size.

" Compared with the control, the combined mixture of lycopene and

vitamin E, at five mg/kg BW each, suppressed the growth of the

prostate xenograft by 73 per cent at day 42, " wrote lead author

Limpens.

Consequently, the mice receiving the combined supplement also lived

40 per cent longer than the placebo group.

While the single supplements did not effect tumour size, the group

receiving five mg/kg BW of lycopene did show slower tumour growth and

a 19 per cent longer survival rate.

The researchers also reported that levels of the so-called prostate

specific antigen (PSA), a protein that is used as a marker for the

disease, tended to be lower in the combo supplement group. Plasma PSA

levels were proportional to tumour size for all groups, adding

support for the use of PSA as a marker of the disease.

Previous research has linked the benefits of tomatoes to the lycopene

content of the fruit, conclusions that are not in-line with the

results of Limpens and her colleagues.

Indeed, it appears as if lycopene and vitamin E exert a cooperative

interaction to protect against prostate cancer growth. The mechanism,

say the researchers, remains speculative but could be due to lower

oxidative stress, altered hormone and growth factor signals, or

apoptosis (programmed cell death).

" On the basis of our findings… we are currently assessing the effects

of lycopene-vitamin E supplementation on rising PSA-levels in an

exploratory phase II clinical prostate cancer trial, " said the

researchers.

According to the European School of Oncology, over half a million

news cases of prostate cancer are diagnosed every year world wide,

and the cancer is the direct cause of over 200,000 deaths. More

worryingly, the incidence of the disease is increasing with a rise of

1.7 per cent over 15 years.