Anti-tumor Effect of Lycopene2010-02-12
Firstly reported by Ernster and Lindberg in 1959 that lycopene possesses the bioavailability of anti-tumor. They found that by injection of lycopene into abdomen of radiated mice, the survival rate was higher and efficient in lowering the risk of bacterial infection. The details information about their research is included in the publications as followed.
★ Modification of the x-irradiation syndrome by lycopene. Exp Cell Res. 1959 Jan; 16(1): 7-14.
★ The promoting effect of lycopene on the non-specific resistance of animals. Exp Cell Res. 1959 Feb; 16(2):384-93.
In the early 80s, researchers have begun to believe that the potent antioxidant nature of lycopene can reduce the probability of DNA mutations which is associated to the lower risk of developing cancer and cardiovascular diseases. Hence, this concept has initiated many epidemiology studies on the intake of green and yellow color fruits and vegetables in correlation to cancer incidents. In 1985, an American Epidemiology study of elderly has shown that high amounts of tomato intake can significantly lower cancer related deaths.
★ Colditz GA, et al. Increased green and yellow vegetables intake and lowered cancer death in an elderly population. Am.J.Clin.Nutr. 1985；41: 32-36. （http://www.ajcn.org/cgi/reprint/41/1/32.pdf）
Many Epidemiology and clinical studies have proven that consuming tomato based products reduce the risk of cancer incidents; especially prostate cancer and other cancers related to gastrointestinal tract. Large number research findings suggest the correlation of lycopene and cancer; public awareness is slowly growing since then.
The most important finding of lycopene was discovered in 1995. Giovannucci et al. from an American health institute carried forward lycopene studies revealed, that intake of Total Carotene, β-Carotene, α-Carotene, Lutein and β-Cryptoxanthin was not correlated to the risk factor. Lycopene is the only key factor in suppressing the tumor growth.
★ Giovannucci E et al. Intake of Carotenoids and Retinol in Relation to Risk of Prostate Cancer. J. Natl. Cancer Inst. 1995; 87: 1767-1776. （http://jnci.oxfordjournals.org/cgi/content/abstract/87/23/1767）
★ Zhang SHM, et al. Measurement of retinoids and carotenoids in breast adipose tissue and a comparison of concentrations in breast cancer cases and control subjects. Am J Clin Nutr 1997; 66: 626-632. (http://www.ajcn.org/cgi/reprint/66/3/626 )
In 1999, it was concluded by epidemiologic literature that lycopene plays a crucial role in prevention of various cancers.
★ Giovannucci E. Tomatoes, tomato-based products, lycopene, and cancer: Review of the epidemiologic literature. J Natl Cancer Inst 1999; 91: 317–31. (http://jnci.oxfordjournals.org/cgi/reprint/91/4/317)
★ Michaud DS, et al. Intake of specific carotenoids and risk of lung cancer in 2 prospective US cohorts. Am J Clin Nutr 2000; 72: 990–997. (http://www.ajcn.org/cgi/reprint/72/4/990)
Since then, Attention has focused on the investigation of direct inhibitory effect of lycopene on cancer cell and it is continued being a popular topic this decade. There are numerous relevant publications, some are listed below.
★ Kotake-Nara K, et al. Carotenoids affect proliferation of human prostate cancer cells. J Nutr. 2001; 131:3303-3306. (http://jn.nutrition.org/cgi/content/abstract/131/12/3303)
★ Tan LL, et al. Lycopene inhibits the growth of human androgen-independent prostate cancer cells in vitro and in BALB/c nude mice. J. Nutr. 2005; 135:287-290. (http://jn.nutrition.org/cgi/reprint/135/2/287 )
★ Chalabi N, et al. The effects of lycopene on the proliferation of human breast cells and BRCA1 and BRCA2 gene expression. Eur J Cancer 2006; 40: 1768-1775.
★ Hwang ES, et al. Inhibitory effects of lycopene on the adhesion, invasion, and migration of SK-Hep1 human hepatoma cells. Exp. Biol. Med. 2006; 231: 322-327. (http://www.ebmonline.org/cgi/reprint/231/3/322)
★ Salman H, et al. Lycopene affects proliferation and apoptosis of four malignant cell lines. Biomed. & Pharmacother. 2007; 61: 366-369.
★ Forneli F, et al. The influence of lycopene on the proliferation of human breast cell line (MCF-7). Toxicol in vitro 2007; 21: 217-223.
★ Palozza P, et al. The growth-inhibitory effects of tomatoes digested in vitro in colon adenocarcinoma cells occur through down regulation of cyclin D1, Bcl-2 and Bcl-xL. British J. Nut. 2007; 98: 789–795. (http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1343148)
Both in vitro and in vivo test however, the effective concentrations of lycopene were in high doses. The discovery concludes that there might be other factors should be taken into account. In 2008, one of the lycopene studies reported that the anti-tumor effect of lycopene alone was limited and it requires the presence of other constituents to exert its chemopreventive potential.
★ Mossine VV, et al. Interaction of tomato lycopene and ketosamine against rat prostate tumorigenesis. Cancer Res. 2008; 68: 4384-4391. (http://cancerres.aacrjournals.org/cgi/reprint/68/11/4384 )
★ Venkateswaran V, et al. A Combination of micronutrients is beneficial in reducing the incidence of prostate cancer and increasing survival in the lady transgenic model. Cancer Prev Res.2009; 2: 473-483. (http://cancerprevention.aacrjournals.org/cgi/content/abstract/2/5/473 )
Recent researches shown that lycopene possesses the capability in modulating the gene expression in proliferation of cancer cells, consequently to inhibit of tumor growth.
★ Audrey KB, et al. Modulation of gene methylation by genistein or lycopene in breast cancer cells. Environ. Mol. Mutagen. 2008; 49:36-45. (http://www3.interscience.wiley.com/journal/117881784/abstract?CRETRY=1&SRETRY=0 )
★ In 1989, Morris et al. collected the data of serum levels of nutrients in tumor patients, lycopene was included as well. The study indicated the fact that low levels of lycopene have been found to be associated with the subsequent development of cancer. Kathy J, et al. Selenium, lycopene, a-tocopherol, β-carotene, retinol, and subsequent bladder cancer. Cancer Res 1989; 49: 6144-6148. (http://cancerres.aacrjournals.org/cgi/reprint/49/21/6144 )
★ In 1991, Campbell et al. found that plasma concentration of carotenoids is lower in breast cancer patients group than that of in normal group. Potischman N, et al. Breast cancer and dietary and plasma concentrations of carotenoids and vitamin A. Am J Clin Nutr 52:909–915, 1990. (http://www.ajcn.org/cgi/reprint/52/5/909 )
★ In 1992, VanEnwyk, etc. also found that lycopene concentration in serum is inverse associated with risk of cervical intraepithelial neoplasia and bladder cancer. VanEenwyk J, et al. Folate, Vitamin C, and cervical intraepithelial neoplasia. Cancer Epidem Biomar 1992；1：119-124.（http://cebp.aacrjournals.org/cgi/reprint/1/2/119 ）
★ In 1994, Italian researchers reported their studies about the effect of tomatoes on risk of cancers of the digestive tract, which data were analyzed from an integrated series of case-control studies conducted between 1985 and 1991 in northern Italy.Franceschi S, et al. Tomatoes and risk of digestive-tract cancers. Int J Cancer 1994; 59: l8l- l84. (http://www3.interscience.wiley.com/journal/112706964/abstract )