Breast Cancer-8

Green Tea

As a tumor grows it elicits new capillary growth (angiogenesis) from the surrounding normal tissues and diverts blood supply and nutrients away from the tissue to feed itself. Unregulated tumor angiogenesis can facilitate the growth of cancer throughout the body. Antiangiogenesis agents, including green tea, inhibit this new tumor blood vessel (capillary) growth.

Green tea contains epigallocatechin gallate EGCG, a polyphenol that helps to block the induction of vascular endothelial growth factor (VEGF). Scientists consider VEGF essential in the process of angiogenesis and tumor endothelial cell survival. It is the EGCG fraction of green tea that makes it a potentially effective adjunct therapy in the treatment of breast cancer. In vivo studies have shown green tea extracts to have the following actions on human cancer cells (Jung et al. 2001b; Muraoka et al. 2002):

Inhibition of tumor growth by 58%
Inhibition of activation of nuclear factor-kappa beta
Inhibition of microvessel density by 30%
Inhibition of tumor-cell proliferation in vitro by 27%
Increased tumor-cell apoptosis 1.9-fold
Increased tumor endothelial-cell apoptosis threefold
The most current research shows that green tea may have a beneficial effect in treating cancer. While drinking green tea is a well-documented method of preventing cancer, it is difficult for the cancer patient to obtain a sufficient quantity of EGCG anticancer components in that form. Standardized green tea extract is more useful then green tea itself because the dose of EGCG can be precisely monitored and greater doses can be ingested without excessive intake of liquids. A suggested dose for a person with breast cancer is 5 capsules of 350-mg lightly caffeinated green tea extract 3 times a day with each meal. Each capsule should provide at least 100 mg of EGCG. It may be desirable to take a decaffeinated version of green tea extract in the evening to ensure that the caffeine does not interfere with sleep. Those sensitive to caffeine may also use this decaffeinated form.

However, there are benefits to obtaining some caffeine. Studies show that caffeine potentiates the anticancer effects of tea polyphenols, including the critical EGCG. Caffeine will be discussed in further detail later in this protocol. Green tea extract is available in a decaffeinated form for those sensitive to caffeine or those who want to take the less-stimulating decaffeinated green tea extract capsules for their evening dose.

Conjugated Linoleic Acid (CLA)
Conjugated linoleic acid (CLA) found naturally, as a component of beef and milk, refers to isomers of octadecadienoic acid with conjugated double bonds. CLA is essential for the transport of dietary fat into cells, where it is used to build muscle and produce energy. CLA is incorporated into the neutral lipids of mammary fat (adipocyte) cells, where it serves as a local reservoir of CLA. It has been proposed that CLA may be an excellent candidate for prevention of breast cancer (Ip et al. 2003). Low levels of CLA are found in breast cancer patients but these do not influence survival. Nevertheless, it has been hypothesized that a higher intake of CLA might have a protective effect on the risk of metastasis (Chajes et al. 2003).

CLA was shown to prevent mammary cancer in rats if given before the onset of puberty. CLA ingested during the time of the "promotion" phase of cancer development conferred substantial protection from further development of breast cancer in the rats by inducing cell kill of pre-cancerous lesions (Ip et al. 1999b). It was determined that feeding CLA to female rats while they were young and still developing conferred life-long protection against breast cancer. This preventative action was achieved by adding enough CLA to equal 0.8% of the animal's total diet (Ip et al. 1999a).

CLA inhibits the proliferation of human breast cancer cells (MCF-7), induced by estradiol and insulin (but not EGF). In fact, CLA caused cell kill (cytotoxicity) when tumor cells were induced with insulin (Chujo et al. 2003). The antiproliferative effects of CLA are partly due to their ability to elicit a p53 response that leads to growth arrest (Kemp et al. 2003). CLA elicits cell killing effects in human breast tumor cells through both p53-dependent and p53 independent pathways according to the cell type (Majumder et al. 2002). Refer to Cancer Treatment The Critical Factors, for more information on determining the p53 status of cancer. The effects of CLA are mediated by both direct action (on the epithelium) as well as indirect action through the stroma.

The growth suppressing effect of CLA may be partly due to changes in arachidonic distribution among cellular lipids and an altered prostaglandin profile (Miller et al. 2001). Intracellular lipids may become more susceptible to oxidative stress to the point of producing a cytotoxic effect (Devery et al. 2001). CLA has the ability to suppress arachidonic acid. Since arachidonic acid can produce inflammatory compounds that can promote cancer proliferation, this may be yet another explanation for CLA's anticancer effects.

Life Extension's recommendation for CLA is a dose of 3000-4000 mg daily, which is approximately 1% of the average human diet. The suggested amount required to obtain the overall cancer-preventing effects is only 3000-4000 mg daily in divided doses.

CLA may work via a mechanism similar to that of antidiabetic drugs not only by enhancing insulin-sensitivity but also by increasing plasma adiponectin levels, alleviating hyperinsulinemia (Nagao et al. 2003) protecting against cancer. A number of human cancer cell lines express the PPAR-gamma transcription factor, and agonists for PPAR-gamma can promote apoptosis in these cell lines and impede their clonal expansion both in vitro and in vivo. CLA can activate PPAR-gamma in rat adipocytes, possibly explaining CLA's antidiabetic effects in Zucker fatty rats. A portion of CLA's broad-spectrum anticarcinogenic activity is probably mediated by PPARgamma activation in susceptible tumor (McCarty 2000). However, CLA’s anticarcinogenic effects could not be confirmed in one epidemiologic study in humans (Voorips et al. 2002). (Note: The term PPAR-gamma is an acronym for peroxisome proliferator-activatedreceptor-gamma. A PPAR-gamma agonist such as Avandia, Actos, or CLA activates the PPAR-gamma receptor. This class of drug is being investigated as a potential adjuvant therapy against certain types of cancer.)

Note: A combination product called Super CLA with Guarana may be used instead of CLA alone. Guarana is an herb that contains a form of caffeine called guaranine, which is 2.5 times stronger than the caffeine found in coffee, tea, and caffeinated soft drinks. What makes guaranine a unique source of caffeine is its slower release due to the guarana seed, which is fatty (even in powder form) as opposed to water-soluble. Caffeine has an inhibitory effect on the growth of cancer and is synergistic with other natural anticancer compounds.


Caffeine
Caffeine occurs naturally in green tea and has been shown to potentiate the anticancer effects of tea polyphenols. Caffeine is a model radio-sensitizing agent that is thought to work by abolishing the radiation-induced G2-phase checkpoint in the cell cycle. Caffeine can induce apoptosis of a human lung carcinoma cell line by itself and it can act synergistically with radiation to induce tumor cell kill and cell growth arrest. The cancer cell killing effect of caffeine is dependent on the dose (Qi et al. 2002).

Caffeine enhances the tumor cell killing effects of anticancer drugs and radiation. A preliminary report on radiochemotherapy combined with caffeine for high-grade soft tissue sarcomas in 17 patients, (treated with cisplatin, caffeine, and doxorubicin after radiation therapy) determined complete response in six patients, partial response in six and no change in five patients. The effectiveness rate of caffeine-potentiated radiochemotherapy was therefore 17%, and contributed to a satisfactory local response and the success of function-saving surgery for high-grade soft tissue sarcomas (Tsuchiya et al. 2000).

In a randomized, double blind placebo-controlled crossover study, the effects of caffeine as an adjuvant to morphine in advanced cancer patients was found to benefit the cognitive performance and reduce pain intensity (Mercadente et al. 2001).

Cancer patients should note that one study demonstrated that caffeine reduced the cytotoxic effect of paclitaxel on human lung adenocarcinoma cell lines (Kitamoto et al. 2003).

To ascertain the inhibitory effects of caffeine, mice at high risk of developing malignant and nonmalignant tumors (SKH-1), received oral caffeine as their sole source of drinking fluid for 18-23 weeks. Results revealed that caffeine inhibited the formation and decreased the size of both nonmalignant tumors and malignant tumors (Lou et al. 1999).

In cancer cells, p53 gene mutations are the most common alterations observed (50-60%) and are a factor in both carcinomas and sarcomas. Caffeine has been shown to potentiate the destruction of p53-defective cells by inhibiting p53's growth signal. The effects of this are to inhibit and override the DNA damage-checkpoint and thus kill dividing cells. Caffeine uncouples cell-cycle progression by interfering with the replication and repair of DNA(Sakurai et al. 1999; Ribeiro et al. 1999; Jiang et al. 2000; Valenzuela et al. 2000).

Caffeine inhibits the development of Ehrlich ascites carcinoma in female mice (Mukhopadhyay 2001). Topical application of caffeine inhibits the occurrence of cancer and increases tumor cell death in radiation-induced skin tumors in mice (Lu et al. 2002). Caffeine inhibits solid tumor development and lung experimental metastasis induced by melanoma cells (Gude et al. 2001).

Consumption of coffee, tea, and caffeine was not associated with breast cancer incidence in a study of 59,036 Swedish women (aged 40-76 years) (Michels et al. 2002).


Melatonin
One of the most important supplements for a breast cancer patient is the hormone melatonin. Melatonin inhibits human breast cancer cell growth (Cos et al. 2000) and reduces tumor spread and invasiveness in vitro (Cos et al.1998). Indeed, it has been suggested that melatonin acts as a naturally occurring anti-estrogen on tumor cells, as it down-regulates hormones responsible for the growth of hormone-dependent mammary tumors (Torres-Farfan 2003).

A high percentage of women with estrogen-receptor-positive breast cancer have low plasma melatonin levels (Brzezinski et al. 1997). There have been some studies demonstrating changes in melatonin levels in breast cancer patients; specifically, women with breast cancer were found to have lower melatonin levels than women without breast cancer (Oosthuizen et al. 1989). Normally, women undergo a seasonal variation in the production of certain hormones, such as melatonin. However, it was found that women with breast cancer did not have a seasonal variation in melatonin levels, as did the healthy women (Holdaway et al. 1997).

Low levels of melatonin have been associated with breast cancer occurrence and development. Women who work predominantly at night and are exposed to light, which inhibits melatonin production and alters the circadian rhythm, have an increased risk of breast cancer development (Schernhammer et al. 2003). In contrast, higher melatonin levels have been found in blind and visually impaired people, along with correspondingly lower incidences of cancer compared to those with normal vision, thus suggesting a role for melatonin in the reduction of cancer incidence (Feychting et al. 1998).

Light at night, regardless of duration or intensity, inhibits melatonin secretion and phase-shifts the circadian clock, possibly altering the cell growth rate that is regulated by the circadian rhythm (Travlos et al. 2001). Disruption of circadian rhythm is commonly observed among breast cancer patients (Mormont et al. 1997; Roenneberg et al. 2002) and contributes to cancer development and tumor progression. The circadian rhythm alone is a statistically significant predictor of survival time for breast cancer patients (Sephton et al. 2000).

Melatonin differs from the classic anti-estrogens such as tamoxifen in that it does not seem to bind to the estrogen receptor or interfere with the binding of estradiol to its receptor (Sanchez-Barcelo 2003). Melatonin does not cause side effects, such as those) caused by the conventional anti-estrogen drug tamoxifen. Furthermore, when melatonin and tamoxifen are combined, synergistic benefits occur. Moreover, melatonin can increase the therapeutic efficacy of tamoxifen (Lissoni et al.1995) and biological therapies such as IL-2 (Lissoni et al. 1994).

How melatonin interferes with estrogen signaling is unknown, though recent studies suggest that it acts through a cyclic adenosine monophosphate (cAMP)-independent signaling pathway (Torres-Farfan 2003). It has been proposed that melatonin suppresses the epidermal growth factor receptor (EGF-R) (Blask et al. 2002) and exerts its growth inhibitory effects by inducing differentiation (“normalizing” cancer cells)(Cos et al. 1996). Melatonin directly inhibits breast cancer cell proliferation (Ram et al. 2000) and boosts the production of immune components, including natural killer cells (NK cells) that have an ability to kill metastasized cancer cells.

In tumorigenesis studies, melatonin reduced the incidence and growth rate of breast tumors and slowed breast cancer development (Subramanian et al. 1991). Furthermore, prolonged oral melatonin administration significantly reduced the development of existing mammary tumors in animals (Rao et al. 2000).

In vitro experiments carried out with the ER-positive human breast cancer cells (MCF-7 cells), demonstrated that melatonin, at a physiological concentration (1 nM) and in the presence of serum or estradiol (a) inhibits, in a reversible way, cell proliferation, (b) increases the expression of p53 and p21WAF1 proteins and modulates the length of the cell cycle, and (c) reduces the metastatic capacity of these cells and counteracts the stimulatory effect of estradiol on cell invasiveness. Further, this effect is mediated, at least in part, by a melatonin-induced increase in the expression of the cell surface adhesion proteins E-cadherin and beta (1)-integrin (Sanchez-Barcelo et al. 2003).

Melatonin can be safely taken for an indefinite period of time. The suggested dose of melatonin for breast cancer patients is 3-50 mg at bedtime. Initially, if melatonin is taken in large doses vivid dreams and morning drowsiness may occur. To avoid these minor side effects melatonin may be taken in low doses nightly and the dose slowly increased over a period of several weeks.


Se-Methylselenocysteine
Se-methylselenocysteine (SeMSC), a naturally occurring organic selenium compound found to be an effective chemopreventive agent is a new and better form of selenium. SeMSC is a selenoamino acid that is synthesized by plants such as garlic and broccoli. Methylselenocysteine (MSC) has been shown to be effective against mammary cell growth both in vivo and in vitro (Sinha et al. 1999) and has significant anticancer activity against mammary tumor development (Sinha et al. 1997). Moreover, Se-methylselenocysteine was one of the most effective selenium chemoprevention compounds and induced apoptosis in human leukemia cells (HL-60) in vitro (Jung et al. 2001a). Exposure to MSC blocks expansion of cancer colonies and premalignant lesions at an early stage by simultaneously modulating pathways responsible for inhibiting cell proliferation and enhancing apoptosis (Ip et al. 2000a).

Se-methylselenocysteinehas been shown to:

Produce a 33% better reduction of cancerous lesions than selenite.
Produce a 50% decrease in tumor development.
Induce cell death (apoptosis) in cancer cells.
Inhibit cancer-cell growth (proliferation).
Reduce density and development of tumor blood vessels.
Down-regulate VEGF (vascular endothelial growth factor).
(Ip et al. 1992; Sinha et al. 1997; Sinha et al. 1999; Ip et al. 2000a, b; Dong et al. 2001)

Unlike MSC, which is incorporated into protein in place of methionine, SeMSC is not incorporated into any protein, thereby offering a completely bioavailable compound. In animal studies, SeMSC has been shown to be 10 times less toxic than any other known form of selenium. Breast cancer patients may consider taking 400 mcg of SeSMC daily.